transesophageal echocardiography during orthotopic liver transplantation: maximizing information...

REVIEW ARTICLE

Transesophageal Echocardiography During Orthotopic Liver Transplantation:Maximizing Information Without the Distraction

Amy C. Robertson, MD, MMHC, and Susan S. Eagle, MD

From the Vanderbilt University School of Medicine, Department ofAnesthesiology, Nashville, TN.

Financial support: Departmental funding.Address reprint requests to Amy C. Robertson, MD, MMHC,

Vanderbilt University School of Medicine, Department of Anesthesiology,1301 Medical Center Drive, 4648 TVC, Nashville, TN 32732-5614.E-mail: [email protected]& 2013 Elsevier Inc. All rights reserved.1053-0770/2601-0001$36.00/0http://dx.doi.org/10.1053/j.jvca.2012.11.016Key words: transesophageal echocardiography examination, liver

transplantation

CARDIOVASCULAR MANIFESTATIONS OF end-stageliver disease (ESLD), coexisting cardiovascular disease

processes, and acute hemodynamic derangements have asignificant effect on the anesthetic management during ortho-topic liver transplantation (OLT). Intraoperative transesopha-geal echocardiography (TEE) has been standard practice forcardiac surgical procedures for more than 2 decades. As aminimally invasive monitor that provides real-time visualinformation on ventricular function and volume status, recentemphasis has been placed on the use of TEE in noncardiacsurgery.1 It naturally follows that TEE can be beneficial duringOLT, specifically for assessment of left and right ventricularvolume status and function and detection of intracardiac air orthrombus, myocardial ischemia, and pulmonary thromboembo-lism.2-6 Although guidelines for the use of perioperative TEEhave been written specifically for skilled examiners, thismanuscript focuses on select views from the comprehensiveTEE examination as defined by the American Society forEchocardiography and the Society of Cardiovascular Anesthe-siologists (ASE/SCA).7-9 These authors propose that a focusedTEE examination with select views will provide helpfulinformation during OLT without detracting from overall patientcare. The goal of this article is to describe advantages forassessment of hemodynamic alterations, diagnosis of potentialcomplications, and initiation of appropriate therapeutic inter-ventions with the utilization of TEE during OLT. A discussionof safety and challenges associated with TEE in patients withESLD also is included.

EVIDENCE-BASED EFFECT OF TEE ON ANESTHETIC

MANAGEMENT DURING OLT

TEE provides real-time visual information regarding dyna-mic function, volume status, overall contractility, regional wallmotion, embolization of large vessels, and pericardial effusion.Several quantitative hemodynamic measurements can beobtained with TEE, including pulmonary artery (PA) pressure,cardiac output, and left atrial pressure. Because chamberpressures may be influenced by factors such as intermittentpositive-pressure ventilation, pulmonary hypertension, valvulardysfunction, and ventricular failure, TEE can provide a moremeaningful interpretation of myocardial wall tension thanpulmonary capillary wedge pressure (PCWP) measurements.10

Evidence supports the inconsistent relationship between PCWPand left ventricular volume (preload) in liver transplantation.11

Decreased left ventricular end-diastolic area (LVEDA) on TEE,consistent with hypovolemia, has been measured in thepresence of normal or even high PCWP values. Further, unlikemeasurements obtained from a PA catheter, TEE allows

Journal of Cardiothoracic and Vascular Anesthesia, Vol ], No ] (Month),

immediate evaluation of systolic function, diastolic function,and preload in critical situations.12-15

Several studies describe the influence of TEE on anestheticmanagement during OLT. Suriani et al12 retrospectivelyevaluated 100 intraoperative TEE examinations performed onOLT recipients. Clinical data that would not have been detectedby other monitoring methods included intracardiac defects,valvular regurgitation, ventricular dysfunction, and occurrenceof air embolization at allograft reperfusion. Unanticipatedfindings during the initial TEE examination and evaluation ofintraoperative events resulted in a significant effect on intra-operative management in 11% of patients. Likewise, in aprospective study by Hofer et al,16 fluid therapy was signifi-cantly influenced by echocardiographic findings in 50% ofpatients during liver and lung transplantation. Ellis et al6

performed TEE to clarify the mechanism of myocardialdysfunction that accompanies OLT. Based upon TEE findings,the authors report that isolated right ventricular failure second-ary to paradoxical emboli may contribute to the hemodynamicinstability seen during OLT.

Numerous case reports also have illustrated the effect ofTEE during OLT. Specifically, several case reports describeearly diagnosis of pulmonary and intracardiac thromboembo-lism through TEE, allowing for initiation of appropriateinterventions and favorable outcome.5,17-20 Fukazawa et al21

describe a case of severe portopulmonary hypertension (POPH)diagnosed at time of OLT. In this situation, TEE was beneficialfor guiding pharmacologic interventions and monitoring rightheart function.

TEE UTILIZATION AND LIMITATIONS DURING OLT

TEE usage among liver transplantation centers is extreme-ly variable. Wax et al22 surveyed 40 high-volume livertransplantation centers in the United States to evaluate TEEutilization. Among 217 anesthesiologists, 86% performed TEE

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dx.doi.org/10.1053/j.jvca.2012.11.016

dx.doi.org/10.1053/j.jvca.2012.11.016

dx.doi.org/10.1053/j.jvca.2012.11.016

Table 1. Absolute and Relative Contraindications to TEE

Absolute Contraindications Relative Contraindications

Esophageal pathology

(stricture, trauma, tumor,

scleroderma, Mallory-Weiss

tear, diverticulum)

Atlantoaxial joint disease

Perforated viscous Severe cervical arthritis

Esophagogastrectomy,

esophegectomy

Esophagitis, peptic ulcer disease

Recent upper gastrointestinal

surgery

Symptomatic hiatal hernia

Active upper gastrointestinal

bleed

History of GI surgery

Recent upper GI bleed

Thoracoabdominal aneurysm

Barrett esophagus

Dysphagia

Coagulopathy, thrombocytopenia

Prior radiation to the chest

Abbreviation: GI, gastrointestinal.

ROBERTSON AND EAGLE2

in some or all OLT cases, with most performing a limited-scope examination. Of TEE users, 12% were board certified toperform TEE. In addition, only 1 center reported having apolicy pertaining to TEE credentialing requirements. Schu-mann23 also conducted a survey of intraoperative resourceutilization in anesthesia for OLT in the United States. Only11.3% of all liver transplantation centers used TEE. The authorconcluded that the infrequent use might reflect the unavail-ability of TEE equipment and unfamiliarity with its use.Routine TEE use also may be influenced by a center’sacademic or nonacademic status or the underlying etiology ofESLD in the recipient population.

Despite the numerous advantages, challenges exist whenusing TEE as a monitoring device during OLT. The inability toobtain a transgastric (TG) view during the majority of livertransplant surgery, due to posterior retraction of the stomach,requires preload to be determined mainly by the midesophageal(ME) 4-chamber view.12 In addition, hemodynamic instabilitymay persist after surgery, especially with patients who exhibitcirrhotic cardiomyopathy physiology. However, TEE monitor-ing cannot be continued easily in the postoperative period.24

TRAINING AND PROFICIENCY

Despite the widespread availability of TEE equipment in UShospitals, o30% of anesthesiologists are formally trained inTEE techniques.10 Specific guidelines for training and certifica-tion in both basic and advanced perioperative echocardiographyhave been developed by the ASE/SCA in partnership with theNational Board of Echocardiography. The scope of practice forbasic perioperative TEE certification is focused on intraoperativemonitoring rather than specific diagnosis, except in emergentsituations. A clinician with advanced skills in TEE must confirmdiagnoses requiring intraoperative cardiac surgical interventionor postoperative medical/surgical management.25

Two pathways are available for basic TEE certification. Thesupervised training pathway, designed for anesthesiologyresidents, requires completion of 150 basic perioperative TEEexaminations under appropriate supervision with a minimum of50 examinations personally performed and interpreted. Super-vised training must be obtained from the Accreditation Councilfor Graduate Medical Education or another national accredita-tion agency-accredited anesthesiology residency program. Thepractice experience pathway, available to board-certifiedanesthesiologists, requires performance and interpretation ofat least 150 basic intraoperative TEE examinations. In addition,40 hours of continuing medical education devoted to periop-erative TEE is mandatory. A final step for certification isachieving a passing score on the National Board of Echocar-diography standardized examination.26

PREOPERATIVE EVALUATION AND TEE SAFETY

Morbidity from TEE insertion and manipulation rangesfrom lip and dental injury (13%) to mortality (0.2%).27,28

Studies have reported that the overall odds ratio for dysphagiais 7.8 times greater for patients in whom TEE was performedand is associated with increased incidence of aspiration andlength of intensive care unit stay.29,30 Hypopharyngeal oresophageal perforation occurs infrequently (0.4%), but is

associated with a high mortality rate.31 Diagnosis of TEE-associated esophageal perforation can be delayed for severaldays, possibly due to limited gastric intake following anesthesiaand surgery.32 Intraoperative or postoperative pneumothorax,subcutaneous emphysema, orogastric/nasogastric bleeding, orpostoperative mediastinitis all indicate a perforated viscus.33

Although patients with ESLD have a theoretically increasedrisk of TEE-associated complications, few complications aredescribed in the literature. A retrospective study by Surianiet al12 of 100 patients who underwent OLT who receivedintraoperative TEE examinations revealed sinus bradycardia andupper gastrointestinal bleeding in 2 patients. Aniskevich et al34

published a case report describing hemodynamic instability duringthe anhepatic phase due to gastric variceal bleeding. Althoughincrease in portal pressure from surgical clamping of the portalsystem likely led to spontaneous variceal rupture, the authorsconcluded that placement of an oral gastric tube or TEE probealso may have contributed to the variceal bleeding. As such,consensus on whether to list esophageal varices as an absolutecontraindication was equivical among committee members inrecent practice guidelines.8 It is recommended that measures betaken in patients with ESLD prior to TEE examination, includingpreoperative endoscopic surveillance, oropharyngeal examination,limiting probe manipulation, and use of the most experiencedoperator for the examination.35,36 Relative and absolute contra-indications are reviewed in Table 1.37

Prior to TEE insertion, the probe should be unlocked,lubricated, and maintained in the neutral or slightly anteflexedposition. Gentle placement over the tongue and into theesophagus should commence. A gentle bilateral jaw thrust bya second provider with slight flexion of the patient’s neck isbeneficial for safe insertion of the probe. Resistance met in theposterior pharynx may be secondary to the probe entering thepyriform fossa. The probe should be withdrawn gently andrepositioned to avoid laceration or perforation. An alternativeinsertion technique employs the use of a rigid laryngoscope tovisualize passage of the probe. Na et al38 recommend thismethod as it may decrease the number of insertion attempts and

TRANSESOPHAGEAL ECHOCARDIOGRAPHY DURING ORTHOTOPIC LIVER TRANSPLANTATION 3

reduce the incidence of oropharyngeal mucosal injury andodynophagia.

Once the probe enters the esophagus, ME views often areobtained at approximately 30 centimeters (cm) distal to theteeth and TG views are obtained at approximately 35 to 40 cm.The majority of views described in this manuscript can beobtained with the probe in the neutral position. To preventsignificant mucosal tears, the tip of the probe always should bereturned to neutral from anteflexion or retroflexion positionsprior to probe manipulation.

PREOPERATIVE TEE ASSESSMENT OF VENTRICULAR

FUNCTION AND VOLUME STATUS

A comprehensive TEE examination is important for baselineassessment and monitoring trends of both volume status andventricular function as the procedure evolves. The authors referto the 20 standard TEE views and standard probe manipulation

Fig 1. Twenty cross-sectional views comprising the recommended com

imate multiplane angle is indicated by the icon adjacent to each view. Repr

aortic valve; asc, ascending; desc, descending; LAX, long axis; ME, mid-es

set forth in the ASE/SCA guidelines (Fig 1).9 To obtainmaximum information from this paper, the reader is encouragedto refer to these guidelines and other TEE-based references.

In the authors’ experience, the most common hemodynamicchanges during OLT are secondary to changes in volume statusand cardiac function. Baseline assessment should includedocumentation of the left ventricular function in all 16 segmentsas outlined in the ASE/SCA guidelines.9 During monitoring,however, the authors focus on a few standard views to improveefficiency and minimize distraction from patient care.

The TG mid-papillary short-axis (TG mid-SAX) view of theleft ventricle (LV) is ideal for evaluating hypovolemia and LVfunction. The TEE probe is inserted gently into the stomach inthe neutral position, with slight anteflexion once in thestomach. The papillary muscles should be visualized in thisview. Inadequate advancement may result in visualization ofmitral leaflets instead of or in addition to the papillary muscles.Papillary muscle proximity at end-systole provides a good

prehensive transesophageal echocardiographic examination. Approx-

oduced with permission. J Am Soc Echocardiogr 12:884-900, 1999. AV,

ophageal; SAX, short axis; TG, transgastric; UE, upper esophageal.

Fig 2. Rapid quantification of volume status or trends by measuring LVEDD. TG SAX of (A) a normal-sized and (B) a dilated LV secondary to

volume overload or decreased ventricular function. Normal left ventricular end-diastolic diameter is approximately 3 to 4 cm. (Color version of

figure is available online.)


visual cue to volume status; the papillary muscles will approachor even touch each other during hypovolemia or decreasedsystemic vascular resistance (SVR).

Quantitative measurements may be useful for monitoringtrends in volume status and ventricular function. Rapidquantification of volume status or trends can be accomplishedby measuring left ventricular end-diastolic diameter (LVEDD).In the TG mid-SAX view, a normal LVEDD is approximately3 to 4 cm. A dilated LV suggests volume overload or decreasedventricular function (Fig 2).

Left ventricle end-diastolic area (LVEDA) is another simplemeasurement of preload. LVEDA can be calculated most easily inthe TG mid-SAX view. The endocardium should be traced at thelevel of the mid-papillary muscles in end-diastole where the LVarea is maximal (Fig 3).39 By convention, the papillary muscles are

Fig 3. Left ventricle volumetric measurements. 2-D measurements fo

Simpson’s rule), in the apical 4-chamber and apical 2-chamber views

muscles should be excluded from the cavity in the tracing. Ejection fra

apical 2-chamber; A4C, apical 4-chamber; EF, ejection fraction; EDV, end

end-diastolic diameter; LV ESD, left ventricular end-systolic diameter. (C

excluded from the tracing. Once traced, ultrasound software cancalculate the LVEDA. Normal LVEDA ranges from 8 to 14 cm2.

Quantitative measurements of left ventricular function canbe obtained by measuring the fractional area of change (FAC).Once LVEDA is obtained, the endocardium is traced during theend of systole for left ventricular end-systolic area (LVESA)(Fig 3).39 FAC (%) ¼ (LVEDA�LVESA)/LVEDA � 100,with normal values ranging from approximately 55% to 65%.Fractional shortening (FS) of EDD and end-systolic diameter(ESD) also can be used to determine ventricular function(Fig 4). FS (%) ¼ (EDD�ESD)/EDD � 100, with normalvalues ranging from 25% to 45%. Obtaining baseline values isprudent for comparison as the procedure evolves.

Although TG views can provide a great deal of information,ME views add additional information and may be necessary as

r volume calculations using the biplane method of discs (modified

at end-diastole (LVEDD) and at end-systole (LVESD). The papillary

ction (EF) ¼ (EDV�ESV)/EDV. Reproduced with permission.39 A2C,

-diastolic volume; ESV, end-systolic volume; LV EDD, left ventricular

olor version of figure is available online.)

Fig 4. Use of LVEDD to estimate ventricular function. Fractional shortening in (A) end-diastole and (B) end-systole can be used to determine

ventricular function: FS ¼ (EDD�ESD)/EDD � 100 (normal 25%-45%); in this example, FS ¼ (3.8�2)/3.8 � 100 ¼ 47%. The close proximity of the

papillary muscles during end-systole commonly is seen in patients during liver transplantation due to hypovolemia and decreased systemic

vascular resistance. FS, fractional shortening. (Color version of figure is available online.)


the stomach is retracted during the surgical procedure. From theTG mid-SAX view, simply withdrawing the probe approxi-mately 5 cm in the neutral position will bring the ME4-chamber into view. This view is advantageous because,unlike the TG mid-SAX, it allows for simultaneous visualiza-tion of atria and ventricles, as well as the mitral and tricuspidvalves. The ME 2-chamber view is obtained by increasing theangle from 01 to �901 with visualization of the left atrium,commissural view of the mitral valve, and anterior/inferiorwalls of the LV. Further increase in the omniplane angle to�1301 allows visualization of the ME long-axis (LAX) viewfor assessment of the mitral valve, ascending aorta, LAX aorticvalve, anteroseptal/inferolateral LV walls, and a distal portionof the right ventricle (RV).

It is paramount to include the RV in the TEE examinationduring OLT for reasons that will be described in this article.A normal RV has an oblong shape and is approximatelytwo-thirds the size of the LV in the ME 4-chamber and TGmid-SAX views. In the ME 4-chamber view, the RV extends

Fig 5. The TAPSE ratio was obtained by measuring excursion of

the tricuspid valve plane from end-diastole to end-systole. LA, left

atrium; LV, left ventricle; RA, right atrium; RV, right ventricle. Repro-

duced with permission. J Clin Anesth 16:104-110, 2004.

more than halfway to, but does not share, the LV apex undernormal conditions. Due to its oblong shape, calculating RVsystolic function may be challenging. A well-accepted andsimple method is the tricuspid annular plane systolic excursion(TAPSE). TAPSE is a measurement of the longitudinalfunction of the RV (Fig 5).40 It has been compared favorablyto RV fractional area shortening and volumetric analysis,though it should be appreciated that this is 1 value for a3-dimensional structure.41 RV dysfunction is represented by aTAPSE value o1.8 cm.

TEE EXAMINATION AND SURGICAL PHASES OF OLT

As previously mentioned, initial TEE examination shouldinclude documentation of the left ventricular function in all 16segments as outlined in the ASE/SCA guidelines. Pathologicfindings also may be encountered during the initial examina-tion. For example, pleural effusions are a known complicationof portal hypertension, with an estimated frequency of 5% inpatients with cirrhotic ascites.42 The descending aortic SAXview allows for visualization of left-sided pleural effusions. Tovisualize the right pleural space, the probe must be rotated tothe right. Chronic pleural effusion volume in milliliters can beestimated with the formula V ¼ 4.5 �CSAmax3/2. CSAmax isobtained by tracing the largest portion of the effusion (Fig 6).43

The Dissection Phase

The dissection or preanhepatic phase begins with surgicalincision and concludes with occlusion of vascular inflow to theliver. The conventional technique involves clamping of both portalflow and vena cava flow from the lower body. The piggybacktechnique, also known as the caval preservation technique, requiresclamping of portal flow only.44,45 Clamping of the inferior venacava (IVC) and portal vein results in decreased venous return,reduced cardiac output, and portal congestion. These changes maylead to hypotension, increased SVR, venous congestion, criticalhypoperfusion of organs, and bleeding from collateral veins belowthe level of the cross-clamp. Adequate preload must be maintainedto ensure perfusion of vital organs.46 Hypotension also may resultfrom temporary obstruction of venous return as a result of surgicalmanipulation of the liver. Transection of large varices and drainage

Fig 6. Pleural effusions in a patient with hepatic failure. (A) Descending aortic SAX view with large LPE. Chronic pleural effusion volume in

milliliters can be estimated with the formula V ¼ 4.5 �CSAmax3/2. CSAmax is obtained by tracing the largest portion of the effusion. (B) Rotation

of the TEE probe to the patient’s right revealed a right pleural effusion. The arrows outline the parenchyma of the right lung. Ao, aorta; CSAmax,

maximum cross-sectional area; LPE, left pleural effusion; RPE, right pleural effusion. (Color version of figure is available online.)


of large quantities of ascitic fluid will contribute to significanthypovolemia. In addition, there is a potential for significanthemorrhage even at this early stage.13

During this phase, the authors recommend the TG mid-SAXview, with particular attention to changes in volume status.Hypovolemia secondary to hemorrhage or decreased venousreturn may result in close approximation of the papillarymuscles and decreases in LVEDA and LVEDD. Alternatively,increased SVR secondary to venous clamping may result inan increased LVEDA, decreased FAC, and global hypokinesis.

Fig 7. ME bicaval view during cannulation for venovenous bypass. (A)

mistaken for thrombus or a cannula. (B) Guidewire placement from the

confirm guidewire placment in the IVC or right atrium, to avoid inadver

arrows) tracks from the IVC through the RA into the SVC, in contrast to

caudad in the direction of the right ventricle. IVC, inferior vena cava; LA,

of figure is available online.)

If this phase is poorly tolerated hemodynamically, venovenousbypass (VVB) might be warranted.

VBB

VVB was developed to facilitate venous blood return fromthe IVC and portal systems to the right heart, with the goal ofminimizing the potential deleterious effects from temporaryclamping of the IVC and portal vein during the conventionaltechnique.3 Advantages associated with VVB include less

Normal bicaval view with arrow pointing to a eustacian valve, often

femoral vein for venovenous bypass cannulation. It is important to

tant arterial cannulation. Note that the guidewire (indicated by the

C, which shows a guidewire from the subclavian vein (arrow) diving

left atrium; RA, right atrium; SVC, superior vena cava. (Color version


hemodynamic instability due to improved cardiac fillingpressures and cardiac output.47 Unintentional decannulation,intracircuit thrombus, and air embolus are potential complica-tions.48 Because the piggyback technique allows for venousreturn to the heart, VVB commonly is not required.44 Clinicalsituations when VVB may be considered include severe portalhypertension, acute liver failure with elevated intracranialpressure, renal dysfunction, and hypotension upon clampingof IVC with the conventional technique.3

The use of TEE has been reported during VVB. Sakai et al49

describe a technique for TEE-guided placement of percuta-neous internal jugular VVB cannula. Specifically, TEE isutilized to confirm the correct location of guidewires in thevenous system and to detect the tip of the cannula inthe superior vena cava (SVC). The TEE probe is placed inthe LAX bicaval view at the ME position. Proper placement ofthe guidewire can be confirmed by visualization from the TEEimage as it passes from the SVC into the right atrium (RA)(Fig 7).50 Viewing the guidewire minimizes the possibility ofinadvertant carotid artery cannulation. Incidentally, the authorscommonly employ this technique when inserting a guidewirefor internal jugular cannulation with a central venous catheter.If the cannula tip is located superiorly within the SVC andcannot be visualized, a bubble test can be performed byinfusing agitated blood or saline through the cannula.Immediate appearance of microbubbles within the RA confirmsthe location of the tip of the cannula in the SVC. VVB alsomay be implemented via femoral venous cannulation. Theguidewire also can be followed from the IVC into the RA. Atthe initiation of the VVB, an ME 4-chamber view is used toensure the immediate and transient visualization of micro-bubble images in the RA. In addition, stable chamber size andwall motion are evaluated to rule out any extravasation of thereturn blood into the thoracic cavity, pericardial space, ormediastinum.49

Fig 8. Intracardiac air during the reperfusion phase via intrapulmona

aorta. Significant amounts of air in the left heart can cause myocardial is

arrows), which is the most anterior coronary artery in the supine patient

right coronary artery. (Color version of figure is available online.)

The Anhepatic Phase

The anhepatic phase occurs with the occlusion of vascularinflow to the liver and terminates with graft reperfusion.46

Hemodynamic alterations encountered during the anhepaticphase primarily are caused by interruption of venous returnfrom the IVC and portal vein. Cardiac output can be reduced by40%-50% with cross-clamping of the IVC and portal vein.3

TEE during this phase primarily is used for distinguishinghypovolemia and decreased SVR from impaired myocardialcontractility. The authors have found that either a TG mid-SAXor an ME 4-chamber view is ideal for continuous monitoring ofright and left ventricular volume status and function during theanhepatic phase. The LV with diminished preload and decreasedSVR will appear to have papillary muscles approximating eachother during systole with a decreased LVEDA (Fig 4). It shouldbe noted that the TG mid-SAX will not be helpful for thedetection of acute mitral or tricuspid regurgitation.

Reperfusion

Graft reperfusion represents the period of greatest hemody-namic disturbance during OLT. Postreperfusion syndromerefers to the significant changes seen in cardiovascular statusfollowing graft reperfusion, and is defined as a decrease inmean arterial pressure of 30% or more from baseline for at least1 minute’s duration and occurring within 5 minutes ofreperfusion.51 The reported incidence of postreperfusion syn-drome ranges between 25% and 50%.51,52 Cardiovascularmanifestations include bradyarrhythmias, decreased mean arter-ial pressure and SVR, and increased mean PA pressure, PCWP,and central venous pressure.51 These cardiovascular alterationsresult from a complex phenomenon likely related to suddenrelease of cold, acidotic, and hyperkalemic preservation fluidalong with vasoactive mediators into the circulation.53

ry shunting. (A) ME LAX view with air in the LA and LV, exiting the

chemia by lodging in coronary arteries, particularly RCA (outlined by

. (B and C in Fig 9). Ao, aorta; LA, left atrium; LV, left ventricle; RCA,

Fig 9. (A) ME RV inflow-outflow view with massively dilated RV following an air embolism. The arrow points to the intra-atrial septum

bowing to the left, a sign of RV failure or RV pressure overload. (B) ME 4-chamber view of severe tricuspid regurgitation, indicated by color

Doppler, secondary to a massively dilated RV and tricuspid valve annulus. AV, aortic valve; LA, left atrium. (Color version of figure is available

online.)


It is helpful to select and maintain a TEE view whentransitioning from the anhepatic to reperfusion phase, typicallyeither the ME 4-chamber or TG mid-SAX view. This will allowfor timely information in the event of hemodynamic instability.Pertinent echocardiographic findings during the postreperfusionphase may include acute right ventricular systolic dysfunctionor left ventricular systolic dysfunction or both with concomitantincreased ventricular end-diastolic volume, increased LVEDA,decreased FAC, global or focal wall motion abnormalities,intracardiac air, intracardiac thrombosis, mitral or tricuspidvalve regurgitation, and severe diastolic dysfunction.2

Significant amounts of venous air can enter the systemiccirculation via intracardiac shunts (patent foramen ovale) orintrapulmonary shunts. Air can embolize to the coronaryarteries, particularly the anteriorly located right coronary artery,resulting in ventricular fibrillation, acute myocardial ischemia,severe right ventricular hypokinesis, and severe tricuspid

Fig 10. (A) TEE image of transgastric LV short-axis view. (B) Left ven

examination. Reproduced with permission. J Am Soc Echocardiogr 12:88

RCA, right coronary artery.

regurgitation, as seen in the ME RV inflow-outflow view(Figs 8 and 9). Likewise, focal or global wall motion abnor-malities and significant mitral regurgitation can be seen in theME 4-chamber or ME LAX view. Left ventricular failure willappear dilated with thin myocardium, elevated LVEDA (Fig 2),and decreased FAC. Furthermore, increased mitral regurgitationmay be detected in the ME 4-chamber or ME LAX view. In theTG mid-SAX view, LV wall motion corresponding to all 3major coronary arteries can be visualized (Fig 10).9 Table 2summarizes useful TEE views for each phase of OLT.

Finally, TEE can be used to view both donor and preservedrecipient IVC following the piggyback technique (Fig 11).From the ME bicaval view, the IVC can be visualized by slightadvancement and rightward turn of the TEE probe. Color-flowDoppler can assess blood flow through the recipient IVC withan absence of flow through the ligated donor IVC. Thrombosisof the ligated IVC is expected to occur.

tricle wall with corresponding coronary arteries during focused TEE

4-900, 1999. S, septum, LAD, left anterior descending, Cx, circumflex,

Table 2. Useful TEE Views During Phases of OLT

Dissection Phase Venovenous Bypass Anhepatic Phase Reperfusion

ME 4-chamber ME 4-chamber ME 4-chamber ME 4-chamber

TG LV short axis TG LV short axis ME LV outflow tract

TG LV short axis

Abbreviations: LV, left ventricular; ME, midesophageal; TG, transgastric.


TEE FOR SPECIFIC CARDIOVASCULAR CONDITIONS

Pulmonary and Intracardiac Thromboembolism

Although OLT is associated with increased bleeding andaltered coagulation, a prothrombotic state may occur. Impairedhepatic clearance of activated procoagulant and antifibrinolyticfactors, deficiencies of anticoagulant proteins, and activation ofcoagulation factors as a result of venous stasis and tissue ischemiaduring surgical dissection and vascular clamping can generate aprothrombotic environment.54 Intravascular thrombosis formationor intracardiac thrombosis formation or both and subsequentembolization is a potentially fatal complication most oftenoccurring after reperfusion. Venous thrombi can embolize intothe RA, right ventricular outflow tract, and pulmonary arteries,resulting in a clinically significant pulmonary embolus (PE).55

Notably, only 30% obstruction is needed for RV dysfunction tobe present on TEE.56 Risk factors include massive bloodtransfusion, presence of VVB, marginal liver grafts, hypercoagu-lability, intraoperative dialysis, and symptomatic or surgicallytreated portal hypertension.4,5,54 Clinical signs of pulmonary andintracardiac thromboembolism include right ventricular failure,decreased TAPSE, tachycardia, hypotension, acute increases incentral venous pressure, and hemodynamic collapse.4

Rapid diagnosis by direct visualization of intracardiac thrombuswith TEE is ideal. Large, proximal emboli may be seen on TEEeither in the main PA or in the right PA (Fig 12). Visualization ofthe left PA by TEE often is not possible due to shadowing fromthe trachea. The right PA on TEE can be visualized in the upperesophagus at zero degrees with slight rightward rotation. In thisview, the SVC and ascending aorta are visualized simultaneouslyin short axis. In the ME 4-chamber view, right ventricular

Fig 11. TEE view of the donor and preserved recipient IVC following th

visualized by slight advancement and rightward turn of the TEE probe.

absence of flow through the ligated donor IVC. Thrombosis of the ligate

figure is available online.)

dysfunction and leftward shift of the interatrial septum orinterventricular septum or both are consistent with elevated right-sided pressures (Fig 13). The LV, however, may appear hyperki-netic and underfilled due to a leftward shift of the interventricularseptum.57 These findings are highly suggestive of a proximal andhemodynamically significant PE. In contrast to patients withpulmonary hypertension, patients with a PE may have apicalsparing of RV dysfunction, or McConnell’s sign, which has a 94%sensitivity and 77% specificity for diagnosing PE.58 These authorsconsistently have noted artifact in the right PA that could easily bemisdiagnosed as a PE. Therefore, right ventricular dilation andfailure with or without McConnell’s sign must be present before aclinically significant PE is diagnosed.

Portopulmonary Hypertension

Portopulmonary hypertension (POPH), a complication ofESLD, has a reported incidence ranging between 5% and8.5%.59,60 Vascular changes associated with POPH includeintimal fibrosis, medial thickening, and hyperproliferation ofsmooth muscle cells and fibroblasts that results in PA occlusion,thrombus formation, and endothelialization of microaneurysmswithin pulmonary arteries. The complex interaction of vasoac-tive, proliferative, and angiogenic mediators leads to endothelialand smooth muscle cell proliferation, vasoconstriction, andthrombosis.61 Diagnostic criteria for POPH include the presenceof mean PA pressure 425 mmHg, pulmonary vascular resis-tance 4240 dynes � s � cm�5, and PCWP o15 mmHg inpatients with advanced liver disease. Patients with systolic PApressures exceeding 80 mmHg have a significantly increasedrisk of perioperative death.62

e piggyback technique. (A) From the ME bicaval view, the IVC can be

(B) Color-flow Doppler indicates blood flow through the IVC and an

d IVC is expected to occur. IVC, inferior vena cava. (Color version of

Fig 12. Pulmonary embolus. TEE of the great vessels, with thrombus visualized in the right pulmonary artery (RPA). SVC, superior vena

cava. (Color version of figure is available online.)


Successful intraoperative treatment of pulmonary hyperten-sion utilizing TEE for monitoring right heart function duringOLT has been described.63 Echocardiographic findings ofsevere pulmonary hypertension include right ventricular dila-tion (Fig 13), right ventricular hypokinesis, decreased TAPSE,and a ‘D-shaped’ interventricular septum. Right ventriculardilation and septal shifting result in a relatively small,hyperdynamic LV. Cardiac output is decreased due to reducedleft ventricular diastolic filling. These findings are similar tothose associated with an acute PE as described previously. TheME 4-chamber view is particularly helpful for assessing theeffects of pulmonary hypertension on the right ventricle.

Hypertrophic Cardiomyopathy/Left VentricularOutflow Tract Obstruction (LVOTO)

Hypovolemia, tachycardia, and increased ventricular contrac-tion can cause apposition of the mitral valve anterior leaflet and

Fig 13. Right ventricular failure. TEE 4-chamber view consistent w

comprises the majority of the apex of the heart in this patient. LA, left a

version of figure is available online.)

the septal wall during systole, resulting in dynamic LVOTO.64

Patients with hypertrophic cardiomyopathy, an inherited disordercharacterized by an abnormally thick LV and acquired leftventricular hypertrophy, are particularly susceptible. Althoughsuccessful liver transplantation has been described in patients withdynamic LVOTO, they are particularly vulnerable for occurrenceof LVOTO during anhepatic and reperfusion phases and itsclinical sequelae.65-67 Dynamic LVOTO can be alleviated byenhancing the distance between the anterior leaflet of the mitralvalve and the septal wall with interventions that increase systemicafterload, reduce ventricular contraction, and decrease heart rate.

TEE is an ideal monitoring technique with which to evaluatecardiac structure and dynamic function associated with hemo-dynamic changes in patients with dynamic LVOTO and toguide therapeutic interventions.68,69 Dynamic LVOTO can beassessed readily in the ME LAX view at an approximately 1301angle. A salient feature to look for is systolic anterior leaflet

ith RV failure, including RV dilation and LV compression. The RV

trium; LV, left ventricle; RA, right atrium; RV, right ventricle. (Color

Fig 14. TEE of hypertrophic cardiomyopathy and left ventricular outflow tract obstruction. Left: Midesophageal left ventricular outflow tract

view. The anterior leaflet of the mitral valve (ALMV) is obstructing the left ventricular outflow tract during systole. Note the hypertrophic

anteroseptal wall of the left ventricle (AS). Right: Same TEE view with color Doppler. Note the turbulent flow through the left ventricular outflow

tract and severe mitral regurgitation; both findings are consistent with systolic anterior motion of the mitral valve. AS, anteroseptal wall; LA, left

atrium; LV, left ventricle; LVOT, left ventricle outflow tract; MR, mitral regurgitation; RV, right ventricle. (Color version of figure is available online.)


motion of the mitral valve (Fig 14). The anterior leaflet andassociated chordae will appear to be perpendicular to theoutflow tract when the aortic valve is opened. Color Doppler,even at a Nyquist limit set at or above 55 cm/s, may reveal amosaic pattern indicating turbulence associated with an ele-vated LVOT gradient. Although this is a rapid qualitativemeasure of obstruction, continuous Doppler through the deepTG LAX view provides a quantitative assessment of theobstruction. Systolic anterior leaflet motion also leads to poorcoaptation of the mitral valve and severe mitral regurgitationwith a posteriorly directed jet on color-flow Doppler. Thedegree of mitral regurgitation correlates to the degree ofoutflow tract obstruction and provides another rapid qualitativemethod of determining the degree of LVOTO.

Due to the dynamic nature of LVOTO, it may be unrecognizeduntil precipiating events, such as hypovolemia and tachycardiaduring OLT, lead to a significant reduction in cardiac output.Aniskevich et al70 describe a case of refractory hypotensionsecondary to dynamic LVOTO in a patient undergoing OLT with

Table 3. TEE Views and

TEE View TEE Angle Probe Position

Midesophageal 4-chamber 01-201 Midesophageal

Midesophageal LV outflow tract 1201-1501 Midesophageal

Transgastric LV short axis 01-201 Transgastric

Abbreviations: LV, left ventricular; LVOT, left ventricle outflow tract, RV

a normal preoperative cardiac evaluation. When routine pharma-cologic interventions failed in the hemodynamic alteration, TEEplayed a critical role in the diagnosis and proper management.

The authors have found that dynamic LVOTO, as diagnosedby TEE, is associated with systemic hypotension and elevatedPA pressure, typically from increased mitral valve regurgitantflow. In the absence of TEE, these hemodyamics fromintravascular monitoring alone would suggest left ventricularfailure, perhaps prompting inotrope administration and diuresis.These maneuvers will, in fact, only worsen the degree ofdynamic LVOTO. Table 3 summarizes the relevant findingsassociated with the TEE views discussed above.

Uncommon Clinical Conditions

Case reports illustrate the pertinent role of TEE in themanagement of various uncommon clinical conditions. A caseof cardiomyopathy secondary to undiagnosed hemochromatosisthat ultimately resulted in refractory hypotension and

Relevant Findings

Relevant Findings

� RV and LV function and size

� Volume status

� Intracardiac air

� Intra-atrial septal defect or bowing

� Intracardiac air

� LVOT obstruction

� SAM

� Wall motion corresponding to all 3 coronary arteries

� Volume status� Difficult to obtain view due to posterior retraction of the stomach

, right ventricle; SAM, systolic anterior leaflet motion.

Fig 15. Apical Ballooning Syndrome on TEE: 2-chamber midesophageal view of the left ventricle in diastole (left) and systole (right). Note

that during systole, only the basal segment of the anterior wall vigorously contracts (arrow), whereas the mid and apical segments remain

akinetic. (Color version of figure is available online.)


cardiogenic shock during OLT has been reported. Intraopera-tive TEE was critical in confirming a dilated cardiomyopathywith severely depressed contractility.71

Sharma et al72 reported a case of unexplained intraoperativecardiovascular collapse after abdominal closure for a successfulOLT. Rescue TEE revealed a large pericardial effusion withcompression of the cardiac chambers, thus confirming thediagnosis of pericardial tamponade. Exploration of the peri-cardial space demonstrated a suture piercing the pericardiumthrough the right hemidiaphragm.

Boucek et al73 describe a patient presenting for OLT whopreviously underwent repair of transposition of the great arteriesin infancy. Anesthetic care proved to be challenging dueto obstruction of the SVC preventing the intraoperative use ofa PA catheter and limiting the options for venous return duringremoval of the native liver. In the absence of reliable conven-tional monitors of preload, the authors depicted observationof right and left ventricular filling by TEE was exceptionallyhelpful.

Takotsubo cardiomyopathy, also known as idiopathic ortransient left ventricular apical ballooning syndrome, is areversible condition most often triggered by stressful events,such as reperfusion of a transplanted liver and exogenous

administration of vasoactive medications.74 Characteristic clin-ical features include ST-elevation on electrocardiogram withoutangiographic evidence of coronary occlusion.75 This syndromehas been reported in the perioperative setting in liver transplantrecipients.76,77 Characteristic TEE findings in the ME 4-chamber and LAX views include hypokinesis or akinesis inthe mid and apical segments of the LV in the absence ofepicardial coronary lesions. Preserved or hyperdynamic func-tion of the basal myocardial segments results in LV apicalballooning as depicted in Fig 15.

CONCLUSION

Intraoperative management of liver transplant recipients ischallenging and significantly affected by cardiovascular man-ifestations of ESLD, coexisting cardiovascular disease pro-cesses, and acute hemodynamic derangements. Althoughcontroversy exists regarding optimal intraoperative monitoring,TEE is a powerful method for assessing hemodynamic altera-tions, guiding resuscitative and inotropic therapy, and identify-ing potential complications during OLT. The authors agree thatsignificant data can be obtained safely with a focused TEEexamination allowing for enhanced patient care.

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