acs surgery: principles and practice

9 SURGICAL TREATMENT OF CAROTID ARTERY DISEASE

The rationale for operating on patients with carotid artery diseaseis to prevent stroke. It has been estimated that in 50% to 80% ofpatients who experience an ischemic stroke, the underlying causeis a lesion in the distribution of the carotid artery, usually in thevicinity of the carotid bifurcation. It would follow, then, thatappropriate identification and intervention could significantlyreduce the incidence of ischemic stroke.

Carotid endarterectomy (CEA) for both symptomatic andasymptomatic carotid artery stenosis has been extensively evaluat-ed in prospective, randomized trials. Symptomatic patients havebeen studied in the North American Symptomatic CarotidEndarterectomy Trial (NASCET),1 the European Carotid StenosisTrial (ECST),2 and the symptomatic carotid stenosis trial from theVeterans Affairs (VA) Cooperative Studies Program.3The results ofall three trials conclusively demonstrate that symptomatic patientswith greater than 50% stenosis on arteriography are at substantial-ly lower risk for stroke after CEA than control subjects receivingmedical management alone. Asymptomatic patients with hemody-namically significant stenosis also benefit from surgical treatment:the Asymptomatic Carotid Atherosclerosis Study (ACAS)4 and theasymptomatic carotid stenosis trial from the VA CooperativeStudies Program5 show that the risk of both transient ischemicattacks (TIAs) and stroke is markedly lower in patients treated withCEA and best medical management than in control subjects treat-ed with best medical management alone. The Medical ResearchCouncil study of the Asymptomatic Carotid Stenosis Trial (ACST)confirmed the findings of these two studies, citing results virtuallyidentical to those originally reported by ACAS.6

Surgical reconstruction of the carotid artery yields the greatestbenefits when done by surgeons who can keep complication ratesto an absolute minimum.The majority of complications associat-ed with carotid arterial procedures are either technical or judg-mental; accordingly, in what follows, I emphasize the proceduraldetails that I consider particularly important for deriving the bestshort- and long-term results from surgical intervention.

Preoperative Evaluation

PATIENT SELECTION

Indications for carotid artery surgery can be divided into twomajor categories: (1) asymptomatic critical stenosis and (2) symp-tomatic hemodynamically significant stenosis.7

Asymptomatic Critical Stenosis

The VA asymptomatic carotid stenosis study, ACAS, and ACSTall found that in patients with diameter-reducing stenosis of 60%or greater on angiography, CEA resulted in fewer fatal and nonfa-tal strokes over a 5-year period than nonoperative treatment withbest medical management alone. It is important to keep in mindthat there are several different ways of measuring stenosis [see 6:2Asymptomatic Carotid Bruit]. The 60% figure cited by ACAS andthe VA study was determined according to the North American

method rather than the European method. Moreover, it was deter-mined by means of contrast angiography rather than duplex ultra-sonography (DUS) or magnetic resonance imaging. If the decisionfor CEA is to be based on DUS, some conversion of values isrequired. A patient who has an 80% to 99% stenosis on DUS cangenerally be assumed to have a diameter-reducing stenosis of atleast 60% on angiography; a stenosis that is less than 80% on DUSmay fall short of a 60% diameter-reducing stenosis on angiography.

Symptomatic Hemodynamically Significant Carotid Stenosis

Both NASCET and ECST found that symptomatic patientswith hemodynamically significant stenoses experienced fewer fataland nonfatal strokes after CEA combined with best medical man-agement than after best medical management alone, provided thatthe perioperative morbidity and mortality from stroke was 6.0%or less. Thus, patients with monocular or hemispheric TIAs aregood candidates for CEA. Global ischemic attacks have also beenused as an indication for CEA.This practice has not been evalu-tated in clinical trials; it is usually justified on the basis of theACAS data alone.

Patients who have previously experienced a hemispheric strokebut who are not disabled and have made a reasonable recovery arealso good candidates for CEA if they have a hemodynamically sig-nificant stenosis.

IMAGING

Identification of a carotid lesion that can be treated with endar-terectomy usually begins with a carotid duplex scan. Indicationsfor carotid duplex scanning fall into three main categories: symp-toms, signs, and risk factors. Symptoms include classic TIAs andstrokes that give rise to clinical suspicion of carotid bifurcation dis-ease.The primary sign is the presence of a carotid bruit on auscul-tation. Risk factors include cigarette smoking, hypertension, dia-betes mellitus, hypercholesterolemia, peripheral vascular disease,and coronary artery disease. As the number of risk factors presentincreases, the likelihood of associated carotid bifurcation diseaseincreases exponentially.

Patients who present with focal ischemic symptoms are likely tohave associated carotid bifurcation disease; however, other patho-logic conditions (e.g., emboli of cardiac origin, aortic arch disease,intracranial vascular disease, coagulopathy, and brain tumors) canalso be responsible for focal symptoms. Accordingly, a completeworkup of a symptomatic patient should include cardiac evalua-tion as well as intracranial imaging.

The accuracy of carotid duplex scanning is highly dependent onthe technician performing it and on the laboratory where it isdone. A carefully performed carotid duplex scan is often the mostaccurate indicator of carotid bifurcation disease; however, a hasti-ly or carelessly performed scan can result in overestimation of theextent of the carotid bifurcation disease. For this reason, addition-al imaging studies (e.g., magnetic resonance angiography, com-puted tomographic angiography, and, when there is serious doubt,contrast angiography) may be indicated.

Wesley S. Moore, M.D., F.A.C.S.

© 2007 WebMD, Inc. All rights reserved.6 VASCULAR SYSTEM

ACS Surgery: Principles and Practice9 SURGICAL TREATMENT OF CAROTID ARTERY DISEASE — 1



Operative Planning

Before operation is scheduled, the general health of the patientmust be assessed, with particular attention paid to cardiac and pul-monary status. Given that many patients with carotid artery diseaseare hypertensive or diabetic, good preoperative control of diabetesmellitus and blood pressure is mandatory. In addition, to reducethe risk of thromboembolic complications, patients should receiveantiplatelet drugs (e.g., aspirin) up to and on the day of operation.Finally, it is well documented that the risk of perioperative cardiaccomplications can be materially reduced by placing patients on acombination regimen that includes a statin and a beta blocker.

ANESTHESIA

Surgery on the cervical portion of the carotid artery may beperformed with the patient under either general or cervical blockanesthesia. Both techniques have their advocates, their advan-tages, and their disadvantages.

The advantages of general anesthesia include a quiet operativefield, maximal patient comfort, and good airway control. In addi-tion, general anesthesia may lead to improved cerebral blood flowand give better protection against reduced blood flow duringcarotid clamping.The disadvantages of general anesthesia includeblood pressure swings during induction and the inability to moni-tor the patient’s conscious response to carotid clamping.Some reportsalso suggest that the incidence of cardiac complications is higherduring general anesthesia than during cervical block anesthesia.

The main advantage of cervical block anesthesia is the ability tomonitor cerebral function during carotid clamping: an awakepatient can be engaged in conversation and can be asked to carryout motor activities of the extremities.The disadvantages of cervi-cal block anesthesia include possible patient discomfort, restless-ness, and intolerance of the longer operations that are sometimesnecessary for technical reasons. Another disadvantage is that onoccasion, a patient cannot tolerate carotid clamping and demon-strates an immediate neurologic deficit with clamp application.Such an occurrence heightens the anxiety level of the surgicalteam, thereby increasing the risk that they will commit technicalerrors in the rush to place an internal shunt.

Besides considering the inherent advantages and disadvan-tages of these two anesthetic techniques with respect to thepatient, it is important to consider their advantages and disad-vantages with respect to individual surgical practice. A given

surgeon may well work better and achieve better results with onetechnique or the other.

Whichever anesthetic approach is used, all patients should havea radial arterial line in place to allow continuous blood pressuremonitoring and to provide access for determining blood gas levels.As a rule, there is no need to place a central venous line or a rightheart catheter, except in patients with marginal cardiac function.

PATIENT POSITIONING

Proper positioning of the patient is necessary to provide opti-mal exposure of the neck from the clavicle up to the mastoidprocess on the side of the proposed operation [see Figure 1].Thepatient is placed in the supine position with a folded sheet underthe shoulders to induce a mild degree of neck extension. Excessiveneck extension should be avoided, however, because it places ten-sion on the artery and actually hinders rather than facilitatesexposure.This potential problem can be addressed by placing oneor more towels under the head to adjust the neck to the optimaldegree of extension.The patient’s head is then turned away fromthe side of the operation to improve cervical exposure further.Finally, the table top may be rotated slightly away from the side ofthe operation so as to provide a flat surgical field.The head of thetable may be elevated slightly if the patient’s blood pressure is ade-quate; this step helps lower venous pressure and reduce venousbleeding during the operation [see Figure 1].

Operative Technique

STEP 1: INITIAL INCISION

Either of two incisions may be used for exposure of the cervi-cal carotid artery.The more common choice is a vertical incisionplaced along an imaginary line that extends from the sternoclav-icular junction to the mastoid process, paralleling the anteriormargin of the sternocleidomastoid muscle as well as the course ofthe carotid artery and the contents of the carotid sheath [see Figure2]. The incision is centered over the presumed location of thecarotid bifurcation. The advantage of this incision is that it pro-

Figure 1 Carotid arterial procedures. Shown is the recommend-ed patient positioning.

Figure 2 Carotid arterial procedures. The incision most com-monly used to expose the cervical carotid artery is a vertical oneplaced along the anterior margin of the sternocleidomastoid mus-cle and centered over the presumed location of the carotid bifur-cation. It may be extended proximally or distally, depending onwhere the carotid bifurcation turns out to be.



vides optimal exposure of the cervical carotid artery and can read-ily be extended either proximally or distally along the aforemen-tioned imaginary line to give additional exposure when needed(e.g., when the carotid bifurcation is unusually high). The disad-vantage of this incision is that it runs against Langer’s lines; thus,if a keloid occurs, it is likely to be in an unsightly position. In mostpatients, the incision heals to a fine line, and it usually is notnoticeable once healing is complete.

The alternative to the vertical incision is a transverse incision thatis placed in a skin crease on the anterior portion of the neck andthen curved toward the mastoid process posteriorly [see Figure 3].

Skin flaps are raised in a subplatysmal layer, and the incision isdeepened along the anterior border of the sternocleidomastoidmuscle.The advantage of this alternative incision is that it may bemore cosmetically acceptable; however, its inferior portion fre-quently crosses the neck anteriorly, which may make it more visiblethan an incision confined to the line of the sternocleidomastoidmuscle would be.The disadvantage of this incision is that it requiresthe raising of skin flaps, which takes additional time and may limitthe extent of any proximal exposure that may be required.

STEP 2: EXPOSURE OF CAROTID ARTERY

Once the incision through the platysmal layer has been com-pleted, an avascular areolar plane is developed along the anteriorborder of the sternocleidomastoid muscle for the full length of theincision so as to expose the carotid sheath. The internal jugularvein is usually the most visible vessel, and the carotid sheath isopened along this vessel’s anterior border. The common facialvein, which drains into the internal jugular vein, is a relatively con-stant landmark. Because the common facial vein is the venousanalogue of the external carotid artery, it can generally be used asa guide to the position of the carotid bifurcation [see Figure 4]. Onoccasion, a patient has several accessory facial veins instead of asingle common facial vein.The common facial vein or the acces-sory facial veins are then divided between ligatures so that thejugular vein can be retracted laterally.The common carotid arteryand the carotid bifurcation lie immediately beneath the dividedfacial veins.

At this point, care must be taken to look for the vagus nerve.This nerve is usually located posterior to the common carotidartery, but it is sometimes rotated into a more superficial posi-tion. Another important neurologic structure in this area is theansa cervicalis, which is formed by the junction of fibers fromthe hypoglossal (12th cranial) nerve and fibers from the first cer-vical nerve and which continues inferiorly as a single trunk, pro-viding innervation to the strap muscles. This nerve should bespared if possible, but it can be divided without significantsequelae if it interferes with optimal exposure of the carotidbifurcation. One convenient method of separating the nervefrom the artery is to divide the fibers running from the first cervical nerve to the ansa cervicalis; when this is done, the nerveis readily mobilized and retracted anteriorly away from thecarotid artery.

The perivascular plane of the common carotid artery is thenentered, and the common carotid artery is circumferentially mobi-lized.The common carotid artery is palpated against a right-angleclamp to determine the proximal extent of the atheroscleroticplaque. If possible, the common carotid artery should be mobi-lized proximal to the plaque until a circumferentially soft portionof that vessel is reached. During mobilization, the vagus nerveshould be identified in its usual location posterior to the vessel andcarefully protected; this nerve sometimes spirals anterior to thecarotid artery as the vessel is dissected distally.

Dissection is then extended distally toward the carotid bifurca-tion and continued along both the internal and external carotidarteries. Excessive manipulation of the area around the carotidbifurcation must be avoided. In particular, it is important to becareful around the bulb of the internal carotid artery: this is wherethe majority of the plaque will be located, and manipulation caneasily dislodge plaque or thromboembolic material.With exposureof the carotid bifurcation, the hypoglossal nerve may come intoview. Care should be taken not to injure this nerve, though it mayhave to be mobilized to permit sufficient distal exposure of theinternal carotid artery.

Figure 3 Carotid arterial procedures. An alternative incision tothe vertical incision is a transverse incision along a skin crease inthe vicinity of the carotid bifurcation.

Common Facial Vein

Internal Jugular Vein

Common Carotid Artery

Figure 4 Carotid arterial procedures. After the sternocleidomas-toid muscle is mobilized off the carotid sheath, the jugular vein isidentified. The perivascular plane along the jugular vein is openeduntil the common facial vein is exposed.



Next, dissection is continued distally beyond the bulb of theinternal carotid artery to a point where the internal carotidartery is normal. At this point, the relevant portion of the vesselis circumferentially mobilized and palpated against a right-angleclamp in at least two planes to confirm that the atheromatousplaque does not reach up to the level of the proposed clamping[see Figure 5]. Once this is accomplished, the external carotidartery is mobilized beyond the end point of plaque extension ina similar manner.

If the patient has a high carotid bifurcation or if the plaquein the internal carotid artery extends further distally thanusual, a more extensive exposure of the carotid bifurcation, theinternal carotid artery, or both is required. To provide suchexposure, the skin incision is extended all the way to the mas-toid process.The sternocleidomastoid muscle is fully mobilizedup to the mastoid process, with care taken to look for the spinalportion of the accessory (11th cranial) nerve as it enters thesternocleidomastoid muscle on the medial surface. With thesternocleidomastoid muscle fully mobilized and retractors inplace, the internal carotid artery can then be further exposed.

The jugular vein is mobilized up toward the base of the skull,with care taken to look for additional accessory facial branches,which must be divided between ligatures so that the jugular veincan be fully mobilized and moved posteriorly. The perivascularplane of the internal carotid artery is carefully defined, and theartery is gently mobilized; the more distal portion of the internalcarotid artery can then be mobilized downward. If the vessel is stillinsufficiently mobile, then the nerve to the carotid body and theascending pharyngeal artery within the crotch between the inter-nal and external carotid arteries are mobilized and dividedbetween ligatures. These two structures often serve as a de factosuspensory ligament for the carotid bulb; dividing them allows thecarotid bifurcation to drop down and permits further downwardtraction of the internal carotid artery as the vessel is gently mobi-lized distally [see Figure 6].

Once the internal carotid artery is further exposed distally andthe hypoglossal nerve is mobilized along its vertical portion andmoved anteriorly, the posterior belly of the digastric muscle isencountered.An areolar plane is developed posteriorly and supe-riorly along the inferior margin of the posterior belly of the digas-tric muscle, allowing the muscle to be mobilized anteriorly toyield additional exposure of the internal carotid artery. If the

Figure 5 Carotid arterial procedures. After the common carotidartery and the internal and external carotid arteries have beenmobilized, the internal carotid artery is palpated against a right-angle clamp in at least two planes (a, b) to confirm that the arteryhas been freed beyond the end point of the plaque.

a

b

a

b

Ascending Pharyngeal Artery Autonomic Nerve

to Carotid Body

Bulb of InternalCarotid Artery

Figure 6 Carotid arterial proce-dures. Once the common, internal,and external carotid arteries arefully mobilized, the structuresbetween the internal and externalcarotid arteries (a) are divided (b)to allow the carotid bifurcation todrop down.

resulting exposure is not sufficient, the muscle may be carefullyencircled with a right-angle clamp and divided [see Figure 7]. Inthose relatively uncommon cases in which even further distalexposure is required, the styloid process is palpated and themuscular and ligamentous attachments to the styloid processdivided, so that the styloid process can be exposed with aperiosteal elevator. Once the styloid process has been complete-ly freed of its muscular and ligamentous attachments and thecranial nerves in the vicinity have been identified and carefullyprotected, the styloid process is cut close to the base of the skull[see Figure 7]. This step yields optimal exposure of the internalcarotid artery all the way to the base of the skull.

Additional adjunctive measures for more extensive exposure ofthe internal carotid artery have been described.These include sub-luxation or dislocation of the mandible,8 wiring of the mandibleinto a subluxed position, and division of the ramus of the mandiblewith rotation of the mandible away from the base of the skull. Inmy view, these measures are unnecessary, provided that the stern-ocleidomastoid muscle and the jugular vein have been adequatelymobilized, the plane around the internal carotid artery has beendeveloped, and the carotid bifurcation has been released.

A significant risk associated with extended exposure of theinternal carotid artery is possible injury to the vagus nerve, theaccessory nerve, or the hypoglossal nerve. Retraction of the vagus



SternocleidomastoidMuscle

SternocleidomastoidMuscle

Common Carotid Artery

Above Digastric1. Superficial Temporal

Artery2. Internal Maxillary

Artery3. Posterior Auricular

Artery

Below Digastric1. Occipital Artery2. Ascending

Pharyngeal Artery3. Facial Artery4. Lingual Artery5. Superior Thyroid Artery

Omohyoid Muscle

Submental Artery

Inferior Alveolar Artery

Exterior Carotid Artery

Interior Carotid Artery

Point of Division ofPosterior Belly of Digastric Muscle

Point of Division ofStyloid Process

Middle Meningeal Artery

Digastric Muscle

First Rib

Vertebral Artery

Figure 7 Carotid arterial procedures. Division of the posterior belly of the digastric muscle yields addi-tional exposure of the internal carotid artery. If the internal carotid artery must be mobilized all the way tothe base of the skull, further distal exposure is obtained by separating the attachments of the ligaments tothe styloid process and dividing the styloid process.

nerve may produce either temporary or permanent vocal cordpalsy, and extensive retraction of or injury to the hypoglossal nervecauses denervation of the ipsilateral side of the tongue, manifest-ed by tongue deviation to the ipsilateral side on protrusion or dif-ficulty with mastication or swallowing. In addition, posterior expo-sure of a high carotid bifurcation may result in injury to branchesof the glossopharyngeal (ninth cranial) nerve.

A common error in carotid artery mobilization is failure to rec-ognize that the plaque in the internal carotid artery extendsbeyond the upper limit of the arterial exposure. It is far better toanticipate this problem before clamping and opening the arterythan to discover it afterward and be forced to mobilize the vesselafter it has been clamped. Once the common carotid and internalcarotid arteries have been mobilized sufficiently, they are encircledwith umbilical tapes; Rumel tourniquets are used if an internalshunt is required or desired.

STEP 3: CEREBRAL CIRCULATORY SUPPORT

Clamping of the carotid artery necessarily results in interruptionof blood flow through the vessel. Patients who have good collateralcirculation via the contralateral carotid artery or the vertebral arter-ies generally (though not always) tolerate the temporary interrup-tion of flow through the clamped artery well.9 Patients who haveinadequate collateral blood flow require cerebral circulatory sup-port, usually in the form of placement of an internal shunt.Thereare three basic approaches to shunt use: (1) routine use of an inter-nal shunt, (2) selective use of an internal shunt, and (3) routineavoidance of shunting in an attempt to minimize clamp time.

Shunting Options

Routine shunting In approximately 10% of patients under-going carotid artery surgery, collateral blood flow is inadequateand temporary use of an indwelling shunt is necessary to preventbrain damage. In the remaining 90%, collateral blood flow is ade-quate and clamping generally well tolerated, and shunting is there-fore unnecessary. Clearly, routine use of an internal shunt takescare of the 10% of patients who require shunts. Its disadvantage isthat it is an additional procedure that carries its own complica-tions, to which not only the 10% of patients who require shuntingbut also the 90% who do not are subjected.The potential compli-cations associated with placement of a shunt include intimal injury(including the raising of an intimal flap), atheroma embolization(if atheromatous material is scooped up during shunt placement),and air embolization (if air bubbles are trapped within the shuntand not recognized).

Selective shunting Selective placement of a shunt has anadvantage over routine placement in that the procedure and itspotential complications are limited to the 10% of patients whoactually require a shunt. Its main disadvantage is that the methodsused to identify patients who require shunting may not be entire-ly reliable.

Selective identification of patients who require shunting can beaccomplished in several ways. The most direct—and perhapssafest—method is to employ local or cervical block anesthesia sothat the effect of temporary carotid clamping can be assessed in aconscious patient; if clamping leads to a neurologic deficit, then thepatient clearly requires an internal shunt. Other methods of identi-fying patients who require a shunt make use of techniques such ascontinuous electroencephalographic monitoring, measurement ofsomatosensory evoked potential, and monitoring of middle cere-bral blood flow with transcranial Doppler ultrasonography.

A useful method of determining the adequacy of collateral cere-

bral blood flow is measurement of back-pressure in the internalcarotid artery.10 Back-pressure has been shown to be a good indexof the adequacy of collateral blood flow, and it correlates well withthe safety of temporary clamping and thus with the necessity ofplacing an internal shunt. Back-pressure is measured by placinginto the common carotid artery a needle that is connected to pres-sure tubing and a pressure transducer.The tip of the needle is bentat a 45° angle. Systemic blood pressure is measured, and clampsare placed on the common carotid artery proximal to the needleand on the external carotid artery. The residual pressure in thecommon carotid artery, which is in continuity with the internalcarotid artery, is then allowed to equilibrate; the resulting pressurereading represents internal carotid artery back-pressure [see Figure8]. It has been determined that patients with back-pressures high-



a

b

Anterior Communicating Artery

Middle Cerebral Artery

Posterior Cerebral Artery

P1

P1 ∝ P2

P2

Basilar Artery

Internal CarotidArtery

Clamp

Figure 8 Carotid arterial procedures. (a) Shown is a graphicrepresentation of the measurement of internal carotid arteryback-pressure. (b) The needle is bent at a 45º angle before beinginserted into the common carotid artery.

er than 25 mm Hg can tolerate temporary clamping withoutincurring brain damage.

The utility of selective shunting in appropriate settings notwith-standing, routine shunting is recommended for patients who havepreviously had a stroke, regardless of the degree of neurologicrecovery. In these patients, a central area of cerebral infarction issurrounded by a zone of relatively ischemic tissue—the so-calledischemic penumbra. The ischemic penumbra is made up of liveand potentially functional brain tissue, but its viability is highlydependent on maximization of cerebral perfusion pressurethrough collateral channels. Accordingly, any interruption ofcarotid circulation, regardless of the degree of collateral circula-tion present, may threaten the ischemic penumbra and extend theinfarct [see Figure 9]. In my opinion, all CEA patients with priorstrokes should receive shunts on a routine basis.

Routine avoidance of shunting The advantage of routine-ly avoiding the use of shunts is that the technical issues and poten-tial complications associated with the additional procedure areavoided entirely.The disadvantage is that unshunted patients withpoor collateral blood flow may sustain ischemic brain damage,particularly if the clamp time turns out to be longer than wasanticipated.

Technique of Shunt Placement

Internal shunts must be placed with great care if shunt-associ-ated complications are to be avoided. Of the various shunts cur-rently available, I prefer the Javid shunt, which is tapered, hassmooth leading edges, and possesses external bulbous circumfer-ential extensions that permit it to be held in place with a circum-ferential Rumel tourniquet, thereby minimizing the chances ofinadvertent dislodgment. Optimal placement of an internal shuntmay be achieved by means of the following steps [see Figure 10].

After the patient has been adequately heparinized and theartery clamped and opened, the distal portion of the internalshunt is placed into the internal carotid artery. A clamp is placed

on the shunt and briefly opened to allow back-bleeding; goodback-bleeding confirms that the shunt is lying free in the lumen ofthe internal carotid artery. The shunt is then secured by tighten-ing a Rumel tourniquet, and the bulbous portion of the shunt isengaged to prevent dislodgment.

Next, the proximal portion of the shunt is placed into the com-mon carotid artery.As this is done, the clamp is removed from theshunt so that backflow from the shunt will dislodge any loosematerial and air within the common carotid artery. The shunt isthen reclamped, and the clamp is removed from the commoncarotid artery as the proximal portion of the shunt is passed intothat vessel.

When the proximal portion of the shunt is in the proper posi-tion in the common carotid artery, it is secured by tightening aRumel tourniquet on the vessel.The clamp on the shunt is thenslowly opened so that the surgeon can observe flow through thetranslucent device and thus verify that no solid particles or airbubbles are passing through it. Because the shunt is relativelylong, the surgeon has a reasonable amount of time in which toobserve flow. If any particles or air bubbles are identified, theshunt can be quickly clamped, removed from the commoncarotid artery, and back-bled, and the procedure can then berepeated.

Once the shunt is secured in place and open, its length andredundancy allow it to be easily manipulated medially and lateral-ly; endarterectomy can then be performed without the encum-brance of an inlying shunt.

STEP 4: RECONSTRUCTION OPTIONS

There are four principal reconstructions involving the com-mon carotid artery and the carotid bifurcation: (1) convention-al open CEA with either patch angioplasty or primary closure,(2) eversion endarterectomy, (3) reconstruction for proximallesions of the common carotid artery, and (4) reconstructionfor recurrent stenosis with resection of the carotid bifurcationand grafting.



Ischemic Penumbra

Embolusin Artery

Middle Cerebral Arteries

Anterior Cerebral Arteries

Posterior Cerebral Artery

Collateral Blood Supply toIschemic Penumbra

Infarct Zone

Figure 9 Carotid arterial procedures. When a thromboembolic fragment occludes a cortical arterial branch, a centralinfarct zone develops, surrounded by an ischemic zone that derives some residual blood supply from collateral vessels.In this zone, known as the ischemic penumbra, the residual blood supply is sufficient to maintain viability.

Open Carotid Endarterectomy

Once the carotid bifurcation has been fully mobilized both prox-imal and distal to the lesion, systemic anticoagulation with heparinis initiated. I generally give 5,000 units, an amount that is sufficientto produce adequate anticoagulation for the duration of carotid clamp-ing but is not large enough to necessitate heparin reversal on comple-tion of the operation. If the patient has been receiving clopidogrel—particularly if clopidogrel was given in combination with aspirin—the heparin dose must be reduced to allow adequate hemostasis tobe achieved after reconstruction. In these cases, I usually limit theheparin dose to 3,000 units. If internal carotid artery back-pressureis to be used to determine whether the patient requires an internalshunt, then it is measured at this time. If cerebral electrical activityis to be the determinant, then the internal, external, and commoncarotid arteries are clamped and electrical activity is monitored(e.g., via EEG) with the clamps in place. If electrical changes arenoted with clamping, an internal shunt is required.

Arteriotomy The common carotid artery and the carotidbifurcation are rotated so as to be positioned for an arteriotomythat begins on the common carotid artery and extends throughthe bulb of the internal carotid artery to a point 180° opposite theflow divider [see Figure 11]. This incision effectively bivalves thecarotid bulb, thus making possible a more accurate primary orpatch closure.The arteriotomy continues through the plaque andextends well up into the internal carotid artery, beyond the visibleend point of the atherosclerotic plaque.

Plaque removal A dissection plane separating the athero-sclerotic intima from the media and the adventitia is then devel-oped with a sharp-bladed dissector. As a rule, it is easiest to begin

the endarterectomy at the point where the plaque is bulkiest. Atthis point, the medial fibers are usually gone, but as the dissectioncontinues both proximally and distally, more normal medial tissuemay be seen. It is important to develop the dissection planebetween the intima and the media if possible because doing sopermits the creation of a feathered end point distally as dissectionproceeds into a relatively normal portion of the internal carotidartery [see Figure 12]. If the dissection plane is between the mediaand the adventitia, a feathered end point is much harder toachieve. Failure to achieve a feathered end point often results in asharp shelf at the internal carotid artery level, which increases therisk of subsequent intimal dissection when blood flow is restored.

Once the dissection plane is complete on one side of the arteri-otomy at the level of the common carotid artery, a right-angleclamp is gently inserted into the plane and advanced through it tothe opposite side of the arteriotomy, thereby separating the plaquefrom the arterial wall around the entire circumference of the ves-sel. The clamp is then gently spread and brought downward tocomplete the circumferential dissection of the plaque proximally.The proximal end point of plaque dissection is obtained by cuttingthe intima with a No. 15 blade.

With the same depth of dissection now existing on both sides ofthe open common carotid artery, dissection then continues distal-ly up to the carotid bifurcation.At this point, the plaque within theexternal carotid artery is carefully separated in a circumferentialfashion. This is usually done by using a sharp mosquito clampuntil all of the plaque has been separated from the vessel wall anddissection has reached normal intima. The freed plaque is gentlygrasped with the opened mosquito clamp, traction is applied, and



Figure 10 Carotid arterial procedures. Shown is the technique ofshunt placement, first distally (a) and then proximally (b).

a b

Figure 11 Carotid arterial procedures: open endarterectomy.Clamps are applied to the common, internal, and externalcarotid arteries, and the structures are rotated (a) so that anarteriotomy can be made in the common carotid artery 180°opposite the flow divider (b).

a b

the distal end point of plaque dissection in the external carotidartery is obtained.

Dissection then continues up the internal carotid artery, withcare taken to leave normal intima behind. Often, the plaquebecomes a relatively narrow tongue of atheroma on the posteriorwall of the internal carotid artery. If the edge of the atheromatousplaque is followed to its end, a tapered, feathered end point can beachieved.

Irrigation and clearing of debris After removal of the spec-imen, the intimectomized surface is vigorously irrigated withheparinized saline. Any medial debris present is carefully removed.The distal end point is irrigated to determine whether there is aresidual flap that might lead to subsequent intimal dissection; ifthere is a flap, it is carefully removed. If there is a sharp shelf at thedistal end point, it is usually an indication that the endarterectomyhas not been carried far enough distally.When this is the case, thearteriotomy should be lengthened so that the endarterectomy canbe extended to a point where the intima is completely normal. Ifthe patient has a very high carotid bifurcation, very distal plaque,or both and further dissection is impeded by the base of the skull,it may be necessary to secure the distal end point with tackingsutures. Tacking sutures should be used only in exceptional cir-cumstances because their use may lead to healing abnormalities orto the presence of platelet aggregate material that can cause throm-boembolic or occlusive complications.

Once the intimectomized surface is completely clear of debris,the lumen of the external carotid artery should be visually inspect-

ed to confirm that all overlying dissected intima has been cleared.Any residual dissected intima can be gently teased out with a mos-quito clamp. Once the vessel is completely clear, preparation ismade for closure of the arteriotomy.

Closure of arteriotomy If the arteriotomy is relatively shortand extends only up to the central portion of the bulb of the inter-nal carotid artery, it can usually be closed primarily with a contin-uous 6-0 polypropylene suture. Placing very small stitches closetogether in the internal carotid artery should minimize the risk ofvessel narrowing.

If the vessel is relatively small or the arteriotomy was extendedwell up on the internal carotid artery to ensure a completeendarterectomy, the arteriotomy should be closed with a patchangioplasty. Of the several patch options available, the basic choiceis between a prosthetic patch and an autogenous patch composedof a segment of saphenous vein obtained from an extremity.Therelative merits of autogenous and prosthetic patches have beenextensively debated in the literature, but no definitive conclusionshave been reached. One of the disadvantages of an autogenouspatch is that surgeons tend to use the entire open portion of thesaphenous vein, which then dilates further under arterial pressure,leading to an artery of aneurysmal proportions.Another disadvan-tage is the potential for patch blowout, which, though rare, hasbeen reported in several series.The main disadvantage of a pros-thetic patch is the risk of infection, but this is extremely low.

At present, it would appear that a prosthetic patch is at least asacceptable as an autogenous patch, and the prosthetic patch has



a b c

Intima Media Adventitia

InternalElastic Lamina

ExternalElastic Lamina

RightDissection Plane

WrongDissection Plane

Figure 12 Carotid arterial procedures: open endarterectomy. (a) Dissection is started where plaque is thickest.Often, medial fibers are completely gone here. Dissection proceeds both proximally and distally along oneside, and more normal medial tissue may be found. Development of a plane between intima and media, ifpossible, is valuable for creating a feathered end point distally. (b) Once dissection is complete on one side,the same plane is established on the opposite side. (c) The end point of proximal dissection is established bysharp division of plaque against the clamp.

an additional advantage in that there is no need to remove a nor-mal saphenous vein segment from an extremity. Prosthetic patch-es can be composed of either fabric or polytetrafluoroethylene(PTFE). Fabric patches now come impregnated with either colla-gen or gelatin to make them leakproof; PTFE patches do not leakon the surface, but they are prone to leakage at suture needlepuncture sites.

Patch size is a crucial consideration: it is important that thepatch be neither too wide nor too narrow. If the patch is too nar-row, it will not provide the additional material needed to restorethe carotid bifurcation to a normal diameter. If the patch is toowide, it will provide too much additional material and create whatvirtually amounts to a carotid aneurysm; this would represent asignificant disadvantage to the patient in terms of flow dynamicsand the risk of producing laminated thrombus in the most dilatedportion of the carotid bulb. My preference is to use a 6.0 mm widecollagen-impregnated fabric patch for patch angioplasty.

Whichever patch is selected is cut to length, beveled at each end,and sewn in place with a continuous 6-0 polypropylene suture.

Before completion of the closure, the internal carotid artery andthe external carotid artery are back-bled and the common carotidartery flushed. The arteriotomy is then completely closed.Removing the clamp on the internal carotid artery allows bloodflow to fill the carotid bulb and permits one last internal flush.Theorigin of the internal carotid artery is then occluded with a vascu-lar forceps, and the clamps are removed first from the externalcarotid artery and then from the common carotid artery to allowresumption of blood flow. After several heartbeats, the forceps onthe origin of the internal carotid artery is removed, and blood flowthrough the internal carotid artery is restored.There may be someleakage of blood along the suture line, which can usually be con-trolled with the placement of thrombin-soaked absorbable gelatin

sponge. If any obvious defect is noted between sutures, an addi-tional stitch should be placed.

Eversion Endarterectomy

Eversion endarterectomy was designed and developed to elim-inate the need for a suture line on the internal carotid artery, in thehope that doing so would reduce the incidence of myointimalhyperplasia and consequent restenosis. There is evidence to sug-gest that the use of eversion endarterectomy has led to somereduction in the incidence of myointimal hyperplasia, but the dataare controversial and certainly are not conclusive. Nonetheless, thetechnique may well have merit, and it should be a part of the vas-cular surgeon’s armamentarium.

Besides the avoidance of a suture line on the internal carotidartery, the advantages of eversion endarterectomy include the sim-ple end-to-side anastomotic closure and the possibility of manag-ing a redundant internal carotid artery by moving it down the com-mon carotid artery. One disadvantage is the potential difficulty ofachieving an end point in cases in which the bifurcation is high orplaque extends well up the internal carotid artery toward the baseof the skull. Another disadvantage arises with patients who requirean internal shunt, in that it is not possible to keep an internal shuntin place for the entire duration of an eversion endarterectomy.Yetanother disadvantage is that the distal end point cannot be viewedas clearly as it can in open endarterectomy. A fourth disadvantageis that eversion endarterectomy is poorly suited to cases in whichthe internal carotid artery is relatively small and contracted andthus better treated with patch angioplasty.

Eversion and plaque dissection After the carotid bifurca-tion is fully mobilized, the internal, external, and common carotidarteries are clamped. A circumferential incision is placed in an



a

c

b d

Line of Division

ArteryEverted

Plaque

Figure 13 Carotid arterial procedures: eversion endarterectomy. (a, b) The internal carotid artery isdivided from the common carotid artery in an oblique line. (c) The divided internal carotid artery iseverted on itself so that it can be separated from the underlying plaque. Eversion proceeds distallyuntil the plaque end point is encountered, and the plaque is removed from the internal carotid artery.Proximal endarterectomy of the common carotid artery and endarterectomy of the external carotidartery are then carried out. (d) Once all of the plaque has been removed, the internal carotid arteryis reverted and an end-to-side anastomosis is fashioned between the common carotid artery openingand the internal carotid artery.

oblique fashion at the junction of the common carotid artery andthe bulb of the internal carotid artery to permit division of the bul-bous portion of the internal carotid artery from the commoncarotid [see Figure 13].The edges of the adventitia of the bulb of theinternal carotid artery are grasped, and the outer layers of the ves-sel wall are gradually everted away from the plaque within theartery. Eversion continues cephalad until it reaches the distal endpoint of the atherosclerotic lesion, which is marked by the presenceof a thin, filmy intima that clearly separates with the specimen, leav-ing normal vessel behind.The plaque in the common carotid arteryand the external carotid artery is then removed in the traditionalmanner; the opening in the common carotid artery may be ex-tended proximally to facilitate this portion of the endarterectomy.

Reversion and reanastomosis The internal carotid arteryis then reverted to its normal anatomic position, and an anasto-mosis between the end of the divided bulb of the internal carotidartery and the common carotid artery is fashioned with a contin-uous 6-0 polypropylene suture. If the internal carotid artery isredundant [see Special Considerations, below], the arteriotomy onthe common carotid artery is extended proximally and the arteri-otomy on the medial aspect of the bulb of the internal carotidartery is extended distally so that the carotid bifurcation may beadvanced between the internal and common carotid arteries toeliminate the redundancy.

Reconstruction for Proximal Lesions of Common Carotid Artery

Lesions at the origin of the common carotid artery, either at thelevel of the aortic arch (in the case of the left common carotidartery) or at the innominate bifurcation (in the case of the rightcommon carotid artery), are relatively rare but do occur. Suchlesions may arise either in isolation or in combination with carotidbifurcation disease. They can be managed by dividing the com-mon carotid artery and transposing it to the adjacent subclavianartery, provided that there is no occlusive disease in the ipsilateralsubclavian artery.

Exposure and mobilization If the lesion at the origin of thecommon carotid artery is the only one being treated, both thecommon carotid artery and the subclavian artery should beexposed through a supraclavicular incision that parallels the clav-icle. If a carotid bifurcation lesion is present in conjunction withthe lesion at the origin of the common carotid artery, the supra-clavicular incision is supplemented with a vertical incision alongthe sternocleidomastoid muscle to permit exposure of the carotidbifurcation. Exposure of the bifurcation has already beenaddressed (see above); accordingly, I focus here on exposure of thesubclavian artery and the proximal common carotid artery.

A supraclavicular incision is placed approximately 1.5 finger-breadths above the clavicle and centered over the lateral head ofthe sternocleidomastoid muscle. The lateral head of the stern-ocleidomastoid muscle is divided, and the scalene triangle isdefined. The scalene fat pad is mobilized off the anterior scalenemuscle.The phrenic nerve is identified, mobilized off the scalenemuscle, and gently retracted. A plane is developed with gentle dis-section between the posterior portion of the anterior scalene mus-cle and the underlying subclavian artery, and the anterior scalenemuscle is divided. Division of the muscle exposes the underlyingsubclavian artery, a sufficient length of which can then be mobi-lized in the perivascular plane to permit an anastomosis.

The jugular vein is identified at the medial aspect of the incisionand mobilized anteriorly and medially to expose the common

carotid artery.The vagus nerve is identified and carefully protect-ed.The common carotid artery is then mobilized both proximallyand distally; proximal mobilization should extend as far behind thesternoclavicular junction as the surgeon can comfortably manage.

Transection and anastomosis The common carotid arteryis clamped proximally and distally, then divided; the proximal por-tion of the vessel is oversewn. The transected common carotidartery is brought posterior to the jugular vein in the vicinity of thesubclavian artery. The subclavian artery is clamped proximallyand distally, a longitudinal arteriotomy is made, and a small ellipseof subclavian arterial tissue is removed. The end of the commoncarotid artery is then sewn to the side of the subclavian artery witha continuous 6-0 polypropylene suture.

Before completion, the vessels are back-bled and flushed. Oncethe anastomosis is complete, blood flow is restored, first to the dis-tal subclavian artery and then to the common carotid artery.

Reconstruction for Recurrent Carotid Stenosis

For an initial recurrence of carotid stenosis that primarilyresults from myointimal hyperplasia, conversion to a patch angio-plasty is generally the best treatment. For second or third recur-rences or for recurrences that develop in spite of patch angioplas-ty, resection of the carotid bifurcation with interposition graftingbetween the common carotid artery and the normal distal inter-nal carotid artery is the best treatment.

Exposure and mobilization Exposure of a carotid bifur-cation for treatment of recurrent carotid stenosis can be chal-lenging. The initial skin incision is reopened, and dissection iscarried down through the scar tissue to the common carotidartery.The common carotid artery is sharply dissected from thesurrounding scar tissue, with the dissection plane kept close tothe adventitia to minimize the risk of injury to the vagus nerveand the hypoglossal nerve. Once the common carotid artery hasbeen adequately mobilized, dissection is carried distally toinclude the carotid bifurcation and the internal carotid artery. Inthe course of distal dissection, care must be taken to watch forthe hypoglossal nerve, which may be incorporated into the scartissue; this structure must be carefully dissected away from theartery and protected.

Distal dissection continues beyond the end point of the previ-ous closure of the internal carotid artery. Beyond this end point,it is usually possible to enter a previously undissected plane of theinternal carotid artery; from here onward, the artery typically issoft around its circumference and is not involved in the recurrentstenosis.The external carotid artery is then mobilized sufficientlyto allow the surgeon to control back-bleeding.

Conversion to patch angioplasty If the artery was origi-nally closed primarily, an arteriotomy is made through the oldsuture line and carried distally through the area of stenosis andonto a relatively normal area of the internal carotid artery.Exploration of the luminal surface usually reveals a smooth, glis-tening neointima, and observation of the cut section of the arteryreveals an area where a whitish, firm thickening of the intimal wallhas occurred as a result of myointimal hyperplasia. No attemptshould be made to reendarterectomize the stenotic area, becausethe intimal lesion is not, in fact, plaque but scar tissue. If the inti-ma is removed, the cascade of events that led to the myointimalhyperplasia will simply be reinitiated. Accordingly, the healed inti-mal surface should be carefully protected. A patch angioplastyacross the stenotic area, extending from the common carotid



artery proximally to a relatively normal portion of the internalcarotid artery distally, is usually sufficient to treat the lesion.

Resection of carotid bifurcation with interposition graft-ing If the stenosis is recurring for the second or third time or theartery was originally closed with a patch, the surgeon should pro-ceed with resection and interposition grafting. In most cases, it isnecessary to sacrifice the external carotid artery and oversew itsorigin. The internal carotid artery is divided distal to the intimalhyperplastic lesion, the common carotid artery is divided proxi-mally, and the diseased specimen is removed.

I prefer to use 6.0 mm thin-walled PTFE for the interpositiongraft.The internal carotid artery distally and the common carotidartery proximally are spatulated by making vertical incisionsapproximately 6.0 mm in length.The PTFE graft is appropriatelybeveled both proximally and distally, and beveled or spatulatedend-to-end anastomoses are performed, first to the internalcarotid artery and then to the common carotid artery.

Before completion, the vessels are back-bled and flushed; oncethe anastomoses are complete, blood flow is reestablished.

Some surgeons may be tempted to use autogenous saphenousvein for the interposition graft. To use such grafts would appear,on the face of it, to be a good idea; in fact, it is a mistake. For rea-sons not clearly understood, the use of autogenous saphenous veinin the neck has an extremely poor track record, yielding unaccept-ably high rates of recurrent stenosis and occlusion in comparisonwith the use of prosthetic grafts.

Special Considerations

Fibromuscular dysplasia of internal carotid arteryFibromuscular dysplasia of the internal carotid artery is a congeni-tal or acquired lesion that has been subdivided into four pathologicvarieties, of which the most common is medial fibroplasia. On con-trast angiography, medial fibroplasia has a characteristic appear-ance, resembling a string of beads in the extracranial portion of theinternal carotid artery [see Figure 14]. A common initial manifesta-tion is a relatively loud bruit in the neck of a young woman.Fibromuscular dysplasia can cause symptoms of monocular orhemispheric TIAs, or it may go on to cause a stroke, usually as aconsequence of a dissection resulting in thrombotic occlusion. Ifsymptoms develop, they can generally be controlled by means ofantiplatelet drugs. Currently, the only indication for surgical inter-vention is the persistence of symptoms despite antiplatelet therapy.

Treatment of fibromuscular dysplasia has evolved over theyears.The first attempts at surgical repair involved a total resectionof the internal carotid artery coupled with interposition of a graft(usually composed of saphenous vein).This technique has largelybeen abandoned because of the extensive surgical dissectionrequired and the substantial risk of cranial nerve injury; its onlyremaining application is in cases where there is associatedaneurysmal dilatation in the dysplastic segment that calls for resec-tion and graft interposition. At present, the two most popularmodes of therapy both involve intraluminal dilatation with disrup-tion of the small septa within the artery. One mode achieves intra-luminal dilatation via an open approach, and the other achievesthe same end via a percutaneous approach that includes balloonangioplasty. Dilatation and fracturing of the intraluminal septaoften result in the release of particles of septal tissue, which in turncan lead to cerebral embolization and infarction. Consequently, anopen approach, which enables the surgeon to flush out the dis-rupted segments, or balloon angioplasty with cerebral embolic pro-tection is usually favored.

In symptomatic patients with fibromuscular dysplasia, thecarotid bifurcation may be exposed in the usual manner. If thereis significant redundancy of the internal carotid artery, as docu-mented by preoperative imaging, the artery should be mobilizedrelatively extensively so that it can be straightened by downwardtraction before intraluminal dilatation is begun. If, on the otherhand, the artery is relatively straight, only minimal mobilization isrequired. It should be kept in mind that approximately 25% ofpatients with fibromuscular dysplasia have associated atheroma-tous disease of the carotid bifurcation that must be dealt with atthe time of operation. In addition, about the same number of



Figure 14 Carotid arterialprocedures: repair of fibro-muscular dysplasia. Depictedis the so-called string of beadsdeformity of the cervical por-tion of the internal carotidartery, which is characteristicof medial fibroplasia.

Figure 15 Carotid arterial procedures: repair of fibromusculardysplasia. (a) The proximal portion of the internal carotid bulb isclamped, a transverse arteriotomy is made, and a coronary dilatoris passed into the internal carotid artery and advanced up the ves-sel to the base of the skull. (b) The small septa in the internalcarotid artery are disrupted by the advancing probe.

a

b

patients have associated intracranial aneurysms that should bechecked for by means of intracranial imaging studies.

Once the carotid bifurcation has been suitably mobilized and ithas been established that no associated atheromatous plaque ispresent, a small transverse incision is made on the bulb of theinternal carotid artery, with flow being maintained between thecommon and external carotid arteries. Serial intraluminal dilata-tions are then performed with coronary artery dilators of progres-sively increasing diameter [see Figure 15].The first dilator (usually2.5 mm in diameter) is passed up the carotid artery to the base ofthe skull under digital control.The dilator is then withdrawn, andthe artery is back-bled to flush out any fractured segments. Thenext larger dilator (3.0 mm in diameter) is passed in a similar fash-ion. Dilatation is repeated with progressively larger dilators (3.5,4.0, and possibly 4.5 mm in diameter) to complete the procedure.

The transverse arteriotomy is closed with 6-0 polypropylenesuture material and flow is reestablished.A completion angiogramverifies that the dysplastic segment is fully restored.

Coiling or kinking of internal carotid artery Redun-dancy of the internal carotid artery, often resulting in a 360° coilof the high cervical portion of the internal carotid artery, is usual-ly thought to be developmental in origin [see Figure 16a]. Elon-gation of the internal carotid artery, which often results in kinkingof the vessel, is believed to be related to the degenerative changesthat occur with aging and atherosclerosis [see Figure 16b]. Both ofthese phenomena, in and of themselves, are usually asymptomatic;exceptions occur when an atheromatous plaque develops at theapex of the coil or when kinking of the internal carotid artery isaccentuated with changes in head position in a patient whodepends on relatively normal blood flow through that vessel.Redundancy of the internal carotid artery often becomes a tech-nical consideration during standard surgical treatment of a carotidbifurcation atheroma.When redundancy occurs, it must be appro-priately dealt with to prevent postoperative complications.

Anticipated redundancy of the internal carotid artery at the timeof carotid bifurcation endarterectomy can usually be managed with

a patch angioplasty. Provided that the arteriotomy extends beyondthe apex of the kink, the patch should smooth out the curvature ofthe redundant vessel and eliminate the kink. If it appears that inter-nal carotid artery redundancy is greater than can be corrected byan elongated patch, then detachment of the internal carotid arteryfollowed by eversion endarterectomy and reimplantation is indicated.

If the arteriotomy has already been closed when it becomesapparent that a kink is present, the problem may be dealt with bymobilizing the external carotid artery sufficiently and then resect-ing a segment of the common carotid artery and pulling down onthe carotid bifurcation with a new end-to-end anastomosis tostraighten the redundant internal carotid artery [see Figure 17].Segmental resection of the internal carotid artery itself combinedwith end-to-end repair has also been described; this approach isless desirable, being more technically demanding and hence moresubject to technical error.

Patients with coiling of the internal carotid artery may presenta more difficult problem. If the atheromatous plaque involves onlythe first portion of the internal carotid artery and the vesselbeyond that first portion is relatively normal up to the point wherecoiling begins, the surgeon can simply avoid the problem by leav-ing the smooth coil in place and not carrying out an extensive dis-tal dissection. If, on the other hand, it appears that there may beplaque in the coil, then the entire coil must be dissected free, andthe patient is left with a very redundant internal carotid artery thatmust be dealt with. Once again, the best method of managing theproblem is to resect the redundant segment of the internal carotidartery, with or without eversion endarterectomy, and to reimplantthe internal carotid artery onto the distal common carotid arteryat the point of transection.



Figure 16 Carotid arterial procedures: repair of coiling or kink-ing of the internal carotid artery. (a, b) Redundancy of the inter-nal carotid artery can result in one or more 360º coils in the ves-sel. (c) Degenerative atheromatous changes of the internal carotidartery can cause elongation with associated kinking or buckling.

Figure 17 Carotid arterial procedures: repair of coiling or kinkingof the internal carotid artery. Kinking or redundancy of the inter-nal carotid artery can be managed by mobilizing the externalcarotid artery, then resecting a segment of the common carotidartery (a). The surgeon can then draw down the carotid bifurcationfor a new primary anastomosis (b).

a b

a b c

Upon completion of the reconstruction, a completion angio-gram should be obtained to verify that the coiling or kinking hasbeen adequately treated.

STEP 5: COMPLETION IMAGING

Given that the majority of neurologic complications aftercarotid artery surgery are attributable to technical error, it isimperative that the technical accuracy of the reconstruction beconfirmed before the incision is closed and the patient is sent tothe recovery room.There are two principal methods of determin-ing the technical quality of the reconstruction: on-table angiogra-phy and direct-contact duplex scanning of the carotid artery. Toperform either of these techniques routinely in all patients addsrelatively little time to the surgical procedure and offers significantadvantages to both the patient and the surgeon.11,12

My preferred method of confirming the quality of the recon-struction is completion angiography using a C-arm with digitalimaging. For this reason, the operation is done on a table that hasangiographic capability, and the radiology technician and theequipment are called for at the beginning of the arteriotomy clo-sure. A 10 ml syringe is connected to flexible tubing, and a 20-gauge needle is attached to the end of the tubing and bent at a 45°angle. Air bubbles are carefully evacuated from the tubing and theneedle. Placing the needle into the artery or, in the case of apatched artery, into the midportion of the patch in a retrogradefashion will provide good stability for the needle, which lies in thelumen of the artery in an axial position. Once the C-arm is in placeand the fluoroscopy unit turned on, the contrast material is inject-ed by hand.The resulting image of the carotid bifurcation can becontinuously replayed until maximal radiographic opacity of thecarotid bifurcation and the intracranial circulation has beenattained. The image is then carefully inspected for defects at theend points in the internal and external carotid arteries.

Intimal defects in the internal carotid artery are unusual,though not rare. Defects in the external carotid artery are morecommon because the endarterectomy is essentially done in a blindor closed manner. Defects in the external carotid artery are mat-ters of concern because they may lead to thrombus formation inthis vessel; if the thrombus propagates proximally, it may embolizeup the internal carotid artery and cause a stroke.13 For this reason,if a defect is found in the external carotid artery, it is repaired atthe time of the operation. To accomplish the repair, clamps areplaced on the external carotid artery proximally at its origin anddistally beyond the intimal flap. A transverse arteriotomy is madein the external carotid artery to permit identification and removalof the intimal flap. Once the flap has been carefully removed, thetransverse arteriotomy is closed with two or three interrupted 6-0polypropylene sutures and flow is restored.

Completion angiography also has the advantage of permittingthe surgeon to image the intracranial circulation. Now that manyoperations are being performed on the basis of preoperativecarotid duplex scanning, intracranial imaging is typically unavail-able beforehand, which means that the status of the intracranialcirculation with respect to atherosclerotic lesions in the area of thesiphon or the middle cerebral artery or with respect to intracranialaneurysms is usually unknown at the start of the procedure. Acompletion angiogram gives the surgeon the opportunity to ruleout these lesions by looking not only at the area around the recon-struction but also at the intracranial circulation.

An alternative to completion angiography is intraoperativeDUS. DUS can be a highly satisfactory way of examining the areaof reconstruction, provided that the operating room has duplexscanning capability and that a technologist is available to operate

the equipment. Standard B-mode imaging, in conjunction withDoppler ultrasonography, can accurately identify patent or com-promised internal and external carotid arteries.

Once the surgeon has confirmed that a good technical recon-struction has been achieved, preparations can be made for closure.

STEP 6: CLOSURE

The dissected area around the reconstructed carotid artery iscarefully irrigated with an antibiotic solution, and the wound ismeticulously inspected for hemostasis. Even when good hemosta-sis has been achieved, it is my practice to place a drain overnight—specifically, a 7.0 mm Jackson-Pratt drain brought out through asmall separate stab wound. The platysmal layer is closed with acontinuous 3-0 absorbable suture, and the skin is closed with acontinuous 4-0 subcuticular absorbable suture. A clear adhesiveplastic dressing is applied to the skin, and the patient is sent to therecovery room.

Postoperative Care

The main patient variables to be evaluated in the postoperativeperiod are neurologic status, blood pressure, and wound stability.

On awakening from anesthesia, the patient is carefully observedwith a view to determining gross cerebral function on the basis ofresponse to commands and movement of extremities. When thepatient is fully awake, vagus nerve and hypoglossal nerve functioncan be tested.

Blood pressure monitoring is of critical importance after CEA.It is essential first to decide on an acceptable blood pressure rangefor the patient and then to ensure that this pressure is maintained:neither hypertension nor hypotension is acceptable. Patients withsevere carotid bifurcation disease who have undergone CEA tem-porarily lose autoregulation on the side of the operation; therefore,hypertension can result in reperfusion injury to that side of thebrain, ranging all the way from simple headache to fatal intracere-bral hemorrhage.

The surgical site should be carefully observed for possiblewound expansion resulting from hematoma formation. Evenwhen good hemostasis is achieved and a drain is in place, there isstill the possibility of delayed bleeding leading to hematoma andairway compromise. If an expanding hematoma is noted, the safestresponse is to return the patient to the OR so that the hematomacan be evacuated and a bleeding site sought. The earlier this isdone, the better.

If the patient is neurologically intact, blood pressure is well con-trolled, and there is no evidence of an expanding hematoma, thenthe remaining postoperative care can be provided in a regular hos-pital room. It is seldom necessary to observe the patient in theintensive care unit, as was once standard practice.

Follow-up

Periodic follow-up examination is essential.There are two majorareas of concern: (1) the possibility of recurrent stenosis on the sidethat was operated on and (2) the possibility of disease developing orprogressing in the contralateral carotid artery. It is my practice tosee the patient approximately 3 weeks after CEA. In that visit, thepatient is examined for quality of wound healing and the presenceor absence of a carotid bruit on both the operated side and the con-tralateral side, and a carotid duplex scan is performed. If at this timethere are no grounds for concern about the contralateral side, scan-ning is done only on the side of the operation.The scan serves toestablish the new baseline and confirms that the carotid reconstruc-



tion is satisfactory. The new baseline is then used as the basis forassessing patient status during subsequent follow-up.

The next patient visit takes place 6 months after operation, atwhich time a bilateral carotid duplex scan is performed. If the oper-ated side continues to be normal and there are no major problemson the contralateral side, the patient is seen again at the 1-yearanniversary of the procedure. If examinations yield satisfactoryresults at this time, the patient may thereafter be seen at 1-yearintervals, with bilateral carotid duplex scanning done at each visit.

Alternatives to Direct Carotid Reconstruction

Carotid angioplasty with stenting (CAS) has been investigatedas a therapeutic alternative to CEA for carotid artery stenosis [see6:10 Carotid Angioplasty and Stenting]. In the Wallstent trial (anindustry-supported prospective, randomized study), patients withstenosis of 60% to 99%, which was angiographically confirmedaccording to the North American method of measurement, wererandomly assigned to undergo either CAS or CEA.14 Initially, itwas proposed that the study would include 700 patients withsymptomatic lesions; however, the trial was stopped by the safety-monitoring committee after 219 patients were randomized. Theresults were reported at the 26th International Stroke Conferencein February 2001.

Of the 219 patients, 107 were entered into the CAS arm and112 into the CEA arm. Patients were well matched with respect toage, gender, symptoms, degree of stenosis, and median follow-up.The primary end point was ipsilateral stroke, procedure-relateddeath, or vascular death within 1 year.At approximately 1 year, theprimary end-point rate was 12.1% in the CAS group and 3.6% inthe CEA group. The 30-day stroke morbidity and mortality was12.1% in the CAS group and 4.5% in the CEA group. Upon ces-sation of the study, the investigators concluded that CAS was notequivalent to CEA for treatment of symptomatic carotid stenosis.

In the SAPPHIRE (Stenting and Angioplasty with Protection inPatients at High-Risk for Endarterectomy) trial, which was also anindustry-sponsored study, CAS with the use of a cerebral antiem-bolism device was compared with CEA.15 Nonrandomizedpatients were entered into either a stent registry or a surgical reg-

istry, but the important part of the study was a randomized, mul-ticenter trial involving 307 patients at 29 investigational sites. Ofthese 307 patients, 156 were entered into the CAS–cerebral pro-tection arm and 151 into the CEA arm. The primary end pointswere (1) death, any stroke, or nonfatal myocardial infarction (MI)within 30 days after the procedure and (2) 30-day major morbidi-ty plus death and ipsilateral stroke between 31 days and 12 monthsafter the procedure. Secondary end points included (1) patency(defined by restenosis < 50%), (2) disabling stroke between 30days and 6 months, and (3) a composite of major adverse clinicalevents at 6 months, 1 year, 2 years, and 3 years.

At 30 days, there were no statistically significant differencesbetween the two study arms when the individual parameters—death, stroke, and nonfatal MI—were considered separately.When these events were viewed in the aggregate, their compositeincidence was 5.8% in the CAS–cerebral protection group and12.6% in the CEA group.When death and stroke were consideredtogether, however, the incidence was 4.5% in the CAS–cerebralprotection group and 6.6% in the CEA group.Thus, it is appar-ent that the major benefit of CAS over CEA lies in reducing theincidence of nonfatal MI.

In November 2006, the results of a large French trial that com-pared CAS with CEA in good-risk symptomatic patients were pub-lished.16 The study design called for the prospective randomiza-tion of 872 patients so as to yield a statistical power of 80%, theaim being to determine whether CAS was not inferior to CEA.After the inclusion of 527 patients, the trial was stopped prema-turely for reasons of unsafety and futility.The 30-day incidence ofany stroke or death was 3.9% after CEA and 9.6% after CAS. At6 months, the incidence of stroke or death was 6.1% after CEAand 11.7% after CAS.16

On the basis of the evidence accumulated to date, the Medicareguidelines are still appropriate. CAS is indicated only for (1)symptomatic patients in whom CEA, in the opinion of a vascularsurgeon, poses unacceptable risks or (2) patients who are willingto participate in an approved clinical trial (e.g., CREST [CarotidRevascularization Endarterectomy versus Stenting Trial]). CEAremains the treatment of choice for patients with suitable lesionsof the carotid bifurcation.



References

1. Beneficial effect of carotid endarterectomy insymptomatic patients with high-grade carotidstenosis. North American Symptomatic CarotidEndarterectomy Trial Collaborators. N Engl J Med325:445, 1991

2. MRC European Carotid Surgery Trial: interimresults for symptomatic patients with severe (70-99%) or with mild (0-29%) carotid stenosis.European Carotid Trialists’ Collaborative Group.Lancet 337:1235, 1991

3. Mayberg MR, Wilson SE, Yatsu F, et al: Carotidendarterectomy and prevention of cerebralischemia in symptomatic carotid stenosis.VeteransAffairs Cooperative Studies Program 309 TrialistGroup. JAMA 266:3332, 1991

4. Endarterectomy for asymptomatic carotid arterystenosis. Executive Committee for theAsymptomatic Carotid Atherosclerosis Study.JAMA 273:1421, 1995

5. Hobson RW II, Weiss DG, Fields WS, et al:Efficacy of carotid endarterectomy for asympto-matic carotid stenosis. The Veterans AffairsAsymptomatic Cooperative Study Group. N EnglJ Med 328:221, 1993

6. Asymptomatic Carotid Surgery TrialCollaborators. The MRC Asymptomatic CarotidSurgery Trial (ACST). Carotid endarterectomyprevents disabling and failed carotid territorystrokes. Lancet 363:1491, 2004

7. Moore WS, Barnett HJM, Beebe HG, et al:Guidelines for carotid endarterectomy—a multi-disciplinary consensus statement from the Ad HocCommittee, American Heart Association.Circulation 91:566, 1995

8. Fisher DF Jr, Clagett GP, Parker JI, et al:Mandibular subluxation for high carotid exposure.J Vasc Surg 1:727, 1984

9. Moore WS, Yee JM, Hall AD: Collateral cerebralblood pressure—an index of tolerance to tempo-rary carotid occlusion. Arch Surg 106:520, 1973

10. Moore WS, Hall AD. Carotid artery back pres-sure—a test of cerebral tolerance to temporarycarotid occlusion. Arch Surg 99:702, 1969

11. Blaisdell FW, Lim R Jr, Hall AD:Technical resultsof carotid endarterectomy: arteriographic assess-ment. Am J Surg 114:239, 1967

12. Schwartz RA, Peterson GJ, Noland KA, et al:Intraoperative duplex scanning after carotid recon-

struction: a valuable tool. J Vasc Surg 7:260, 1988

13. Moore WS, Martello JY, Quiñones-Baldrich WJ, etal: Etiologic importance of the intimal flap of theexternal carotid artery in the development of post-carotid endarterectomy stroke. Stroke 21:1497,1990

14. Alberts MJ: Results of a multicenter prospectiverandomized trial of carotid artery stenting vs.carotid endarterectomy (abstr). Stroke 32:325d,2001

15. Yadav J, for the SAPPHIRE Investigators: Stentingand angioplasty with protection in patients at highrisk for endarterectomy: the SAPPHIRE study(abstr). Circulation 106:2986a, 2002

16. Mas J-L, Chantellier G, Beyssen B, et al:Endarterectomy versus stenting in patients withsymptomatic severe carotid stenosis. N Engl J Med355:1660, 2006

Acknowledgment

Figures 1 through 17 Tom Moore.

acs surgery: principles and practice

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