chronic lower limb ischemia

CHRONIC LOWER LIMB ISCHEMIA

Dr Minhajuddin KhurramAl-Ameen Medical College

Bijapur (Karnataka)India

DefinitionPeripheral areterial occlusive disease (PAOD/PAD/PVD) refers to the obstruction or detoriation of ateries other than those supplying the heart and within the brain

Epidemiology & Risk factors

Impairment of circulation Incidence increases with age

0.3%/yr (40 to 55yrs) to 1%/yr (after 75yrs) Quality of life/cost of treatment Non whites> whites Male gender Obesity


Black (hispanic) Increasing age Smoking Hypertension Dyslipidemia Hypercoaguble states Renal insufficiency DM

Younger>aged


Family history of vascular disease or stroke/ heart attack

In study C-reactive protein Homocysteine

Anatomy

Micro Anatomy

Intima Internal elastic membrane

Media Composed of smooth m/s, collagen, elastin and

preteoglycans Blood suply:

Internal half: Direct diffusion External half: vasa vasorum

External elastic membrane Adventitia

• Fibroblasts and collagen

Micro Anatomy

Acute vs Chronic Occlusion Acute

Sudden occlusion of an artery No time for collateral openings Poikilothermia, Pain, Pulseless, Pallor,

Parasthesia and Paralysis Chronic

No sudden obstruction Gradual narrowing of lumen Enough time for collaterals to develop More tolerant to prolonged ischemia

Causes of Chronic Occlusion

Atherosclerosis {lower limb}

TAO (Buerger’s Disease) {lower limb}

Infective

Vasculitis syndromes

Atherosclerosis

Atherosclerosis Atherosclerosis =

Athero + sclerois Plaque composed of

smooth m/s, lipids, connective tissue and macrophages

Atherosclerosis Brief pathophysiology

Lipid deposition calcificationerosive areas and

ulceration prothrombotic cell activity plaque

lipid core becomes necrotic covered by FIBROUS

CAP rupture, perceived as injury laying down of

platelets and formation of a clot.

Atherosclerosis Ischemia may be due to

Narrowing of the lumen Rupture leading to fibrous cap Embolization

Atherosclerosis More shearing

stress/ increased turbulence Infra renal aorta Iliac bifurcation Carotid bifircation Superficaial femoral

arteries Ostia or renal,

coronary and mesenteric arteries.

Buerger’s Disease Inflammatory reaction of the arterial wall

with involvement of neighboring vein and nerves

2nd to 4th decade of life; male>females Specifically linked to smoking Low socio-economic groups Recently, familial disposition and

autoimmune mechanism has also been postulated

Buerger’s Disease

Buerger’s Disease Pathology

smoking (nicotine)

Increased % carboxy hb

vasospasm damage to the vessel wall

TAO fibrosis

Buerger’s Disease Involves medium and small sized vessels;

those distal to the popliteal artery Very rare upper limb involvement Acute Lesion:

Arteritis, periarteritis, acute phlebitis (migratory in 30%) and periphlebitis.

Invasion of wall by polymorphs and giant cells. Thrombus, with microabscesses

Buerger’s Disease Chronic Lesion

Arteries and veins bound together by fibrosis Nerve involvement Fibroblastic activity and endothelial

proliferation in the thrombus Thrombus organized as fibrous tissue

Clinical Manifestation Pain (Intermittent claudication)

“Claudio”= I limp Cramp like pain Brought on by exercise Not present on walking the first step Relieved by standing still Slight variation each day

Due to accumulation of substance P Site of Claudication:

Group of muscles distal to the site of obstruction


Clinical Classificationa) Boyd’s Classification

Grade PainI Pain relieved on continued walkingII Walks in painIII Compelled to take restIV Pain at rest

Clinical Manifestation Claudication distance : distance at which

the pain first appears

Clinical Manifestationb) Fontaine Classification

Clinical Manifestationc) Rutherford Classification


Occlusion and site of claudicationSite of Occlusion Claudication site/ other symptomsAorto-iliac obstruction

• Claudication in in both buttocks, thighs and calf

• Absent femoral, popliteal and DP pulses• Impotence (Leriche’s syndrome)

Iliac obstruction • Unilateral claudication in thigh and calf• Unilateral absence of femoral and distal

pulses

Femoropopliteal obstruction

• Unilateral claudication in the calf• Absent distal pulses

Distal obstruction • Ankle pulses absent• Claudication in calf and foot


Rest pain Grade IV Boyd’s classification Felt in the foot (most distal parts) Due to ischemia of the somatic nerves (cry of the

dying nerves) Exacerbate on lying down or elevation of foot Worse at night; patient sits in “hen-holding” position Pressure of even bed clothes worsens the pain Lessened by hanging the foot down or sleeping on a

chair Patient may commit suicide


Rest pain – “Hen-holding”


Critical limb ischemia Persistently recurring ischemic rest pain

requiring regular, adequate analgesia for more than 2 weeks or ulceration or gangrene of foot or toes with ankle pressure <50mmHg or toe pressure <30mmHg


Differential Diagnosis1. Nerve root compression (eg: herniated disc)

Sharp lacinating painSudden onset on walkingHistory of back problems

2. Spinal stenosisHistory of back problemsMotor weakness more prominentOnset by standing alsoRelived by change in position


Differential Diagnosis3. Arthritic/ inflammatory

Aching painVariable painNot relieved as quickly

4. Baker’s cystSwelling, tendernessRest painSubsides slowlyNot intermittent


Differential Diagnosis5. Venous claudication

Bursting type of painRelief speeded by elevationh/o DVTSigns of venous congestion

6. Chronic compartment syndromeBursting painHeavily muscled legsRelief speeded by elevation

Clinical Manifestation Other symptoms

Ulceration Gangrene Loss of senstion Loss of movements

Clinical Assessment History

Can identify the location and severity of the disease Pain:

Location Precipitating and aggravating factors Frequency, duration and evolution

Rule out other causes of pain in the lower limbs Patients with co- morbid conditions who cannot walk

present late with gangrene and rest pain Drug/Medical history Surgical history Family history : first degree with abdominal aortic

aneurysm

Clinical Assessment History

Vascular review of symptoms TIA Difficulty in speech or swallowing Dizziness/ drop attacks Blurry vision Arm fatigue Pain in abdomen after eating Renal insufficiency (poorly controlled hypertension) Impotence Claudication Rest pain or tissue loss

Clinical Assessment Physical examination

Inspection Change in colour Signs of ischemia Bueger’s test Capillary filling test Venous refilling Pregangrenous/ gangrenous part examination


Palpation Skin temperature Venous refilling Perpheral pulses

Disapperaing pulse Joint movements / muscle strength Sensations

Auscultation: Bruits


Dry vs Wet GangreneDry gangrene Wet gangrene

Dry, shriveled, mummified Odematous, putrified and discoloured

Occurs due to slow and gradual loss of blood supply

Occurs due to sudden loss of blood supply

Clear line of demarcation is present

Vague/ No line of demarcation

No proximal extention Proximal extension

Limited amputation High amputation


Dry vs Wet Gangrene

Investigations ABPI

Investigations ABPI

Physiological testingSBP of PT/PT/PA (higher)--------------------------------- = ABPIHigher of the two brachial SBPs

Normal value =>1 Claudication <0.9 Rest pain <0.5 Imminent necrosis <0.3

Note: Normal value doesn’t rule out ischemia Retest after exercise, ABPI may fall Wrong high readings in calcified arteries, e.g. seen in diabetics

&ESRD

Investigations ABPI Note:

Normal value doesn’t rule out ischemia Retest after exercise, ABPI may fall Post exercise ABPI considered POSITIVE when

ABPI fall => 0.2 and/or Failure to return to baseline in 3 minutes

Wrong high readings in calcified arteries, e.g. seen in diabetics &ESRD

Investigations Segmental pressure

Difference of 20-30 mmHg is indicative of significant lesion

Investigations Photo-Plethysmography

Investigation for segmental flow

Infra-red light emitting source + a photosensor

Light decreases when flow increases

Generates a pressure and waveform of different

arteries

A difference of 20-30 mmHg is significant.

Investigations Doppler Ultrasound

(DU) Continous wave DU with

segmental waveforms Doppler shift converted

to audio signal Normal Triphasic Signal

Sharp systolic upstroke

Reversal of flow in early diastole

Low amplitude forward flow

throughout diastole.

Investigations Doppler Ultrasound (DU)

Obstructive disease Initial Loss of reversal flow in early diastole (Bi-phasic) Severe blunting of arterial waveform with decreased

amplitude Worsening only diastolic flow (Mono-phasic )

In case of a proximal obstruction/ stenosis Assessment downstream is less accurate

Shows moving blood but it may/ may not be sufficient

Investigations Doppler Ultrasound

(DU)

Investigations Duplex Ultrasound

Provides with B mode settings (gray settings)

Pulsed Doppler spectral waveforms

Can even detect very low flow states

Color flow data and waveforms for analysis by a computer.

Shows blood flow and turbulence

Peak systolic velocities (PSV) and End diastolic velocities are

recorded.

Investigations Duplex Ultrasound

Change in waveforms Triphasic biphasic Monophasic

Ratio of PSV proximal and distal to occlusion >2.0 indicates a stenosis of 50% or more

Difficult in aoto-illiac segments, especially in obese individuals

(patient should fast overnight)

Investigations Angiography

Invasive techique of visualising the arterial tree Hypaque 45 (Sodium Diatrazoate) is used as a dye

(75 to 100 ml) Course of arteries, constrictions, and distal “Run

off” To plan interventions

1. Transfemoral2. Trans-lumbar (established bi-lateral obstruction)

Seldinger technique is used


Done in 4 stagesi. Dye released at the level of diaphragm in the aorta

Abdominal aorta Celiac artery Sup mesenteric artery Inferior mesenteric artery

ii. Dye released at aortic bifurcation B/L common iliac arteries Hypogastric arteries External iiliac arteries Common femoral arteries Sup Femoral arteries Profunda femoris


Done in 4 stagesiii. Contralateral common femoral artery

Contralateral Sup Femoral artery Profunda femoris Popliteal artery 3 crural arteries Pedal arteries

iv. Ipsilateral common Femoral artery Sup Femoral artery Profunda femoris Popliteal artery 3 crural arteries Pedal arteries


Site of block in Atherosclerosis


Cork-screw pattern of vessels in TAO

Block at multiple sites in small and medium sized arteries


Risk / Complications:a) Groin hematomab) Retroperitoneal bleedingc) Pseudo-anuerysmd) Arterial dissectione) Contrast nephropathyf) Contrast allergy

Investigations CT angiography

IV contrast followed by Ct imaging Thin slices of 0.625mm Allows 3-D reconstruction Improved speed Lesser contrast material Appreciation of thrombus, calcification, etc. better Disadvantages similar to angiography

Investigations Digital subtraction angiography (DSA)

Angiographic images being digitilised by a computer

With substraction of extrenous background (bone, soft tissues)

Investigations MR angiography

Uses Godalinium as contrast Better sensitivity and specificity Disadvantages:

longer study duration Costlier Metallic implants contra-indication Nephrotoxic contrast Fibrosed nodules of skin, eyes and joints (rare

complication)

Investigations Carbon Dioxide angiography

CO2 as contrast agent In cases of renal insuffieciency CO2 temporarily displaces blood but dissolves in

3-5 minutes Poor detail Significant patient discomfort Gas trapping mesenteric ischemia

Investigations General Investigations

ECG ECHO Lipid profile COPD Blood tests to exclude

Anemia DM Deranged RFT High blood viscosity (polycythemia and

thrombocythemia)

Investigations Intravascular

ultrasound (IVUS) Catheter based

intravascular ultrasound

Provides transverse and 360 degree image of the lumen of the vessel

Qualitative data about the wall anatomy

Investigations Brown’s vasomotor index

For Buerger’s disease Test of vasospasm Block the nerves with Local anesthesia to

predict efficacy of Sympathectomy Rise in skin temperature is recorded Index = Rise in skin temperature – Rise of mouth

temperatureRise of mouth temperature

Index =>3.5 is positive for sympethectomy

Management Conservative management

Indications: Ankle pressure >60mmHg Femoral pulse + No rest pain No tissue loss Controlled infection (eg diabetic patient) Unfit for surgery ABPI >0.5 (Relative indication)


Stop smoking Keep walking Reduce weight (obese individuals) Exercise Diabestes and hypertension Care of feet Buerger’s position Buerger’s exercise


Drugs Analgesics- Aspirin Vasodialtors

Cilostazol (phosphodiasterase inhibitors) Pentoxyphylline (phosphodiasterase inhibitors) Prostacycline

Platelet aggregation inhibitors Clopidrogel Aspirin Prostacycline


Drugs To Control

Diabetes Hypertension Dyslipidemia Atherosclerosis Infection

Note: Risk of limb Loss to be explained to the patient (Failure in 25% of patients)

Opening up of collaterals or change of gait with less usage of the affected muscle

Management Indirect surgeries

Sympathectomy Chemical Surgical Indications:

Rest pain Skin ulcerations TAO Elderly patient (senile gangrene)


Sympathectomy Chemical

Produces cutaneous vasodilatation Injection in front of the lumbar fascia which contains

sympathetic trunk; Under C-Arm 5ml phenol in water is inected in front of 2nd, 3rd and

4th lumbar vertebra


Sympathectomy Surgical (pre-ganglionic sympathectomy)

Abdomen opened with oblique incision under genral anasthesia

Dissection through flat abdominal muscles, and peritoneum

The sympathic chain is situated medial to the medial margin of psoas muscle

Rt side overlapped by IVC Lt side overlapped by aorta Sympathetic chain identified by the presence of ganglia First lumbar ganglia is as high as crus of the diaphragm


Sympathectomy Surgical

Sympathectomy from 1 to 4th lumbar ganglion Closed the site in layers

Note: in case of bilateral surgery; preserve L1 of atleast one side causes retrograde ejaculation.

Management

Management Surgical Management

Surgical Revascularization Procedures Open Endo-vascular

Amputation

Management Surgical Revascularization Procedures

Open vs endo-vascular Trans-Atlantic Inter Society Documentation

Management of Peripheral Arterial Disease (TASC) 2000

TASC –II in 2007“Endovascular therapy is the treatment of choice for Type A lesions and surgery is the treatment of choice for Type D lesions. Endovascular treatment is the preferred treatment for Type B lesions and surgery is the preferred treatment for good risk patients with Type C lesions”

Management TASC –II (Aorto-iliac)

Management TASC –II (Femoro-popliteal)

Management Open Surgical Management (Aorto-iliac

disease) Aorto-bifemoral bypass with a prosthetic graft via

transabdominal or retroperitoneal approach. End to end or end to side proximal anastomosis Nervi erigentes should be taken care of (damage

will lead to retrograde ejaculation) in the area of CIA

Mortality 5%

Management Open Surgical Management

Choice of Graft (Conduits) Great Sephanous vein

Preferred for lower limbs with better patency rates (90% First yr and 60% five yrs)

Should preferentially be used in all below knee by-passes Can be used in situ

Better size match Removal of valves with valvulotome

Reversed No need of disruption of valves May be harvested endoscopically

No added advantage of one over the other


Choice of Graft (Conduits) PTFE (Polytetrafluoroethylene)

Can be used as a replacement of LSV Poorer results compared to LSV (50% in five yrs) New: with heparin coating

Dacron is a brand name of PTFE


Choice of Graft (Conduits) Small sephanous vein Basillic vein Cephalic vein

All these three veins have very thin walls, hence no good results

veins when joined to increase the length gives poor results

Cryo-preserved arteries Cadevaeric arteries preserved in cold

Bovine pericardial patches


disease) Aorto-bifemoral bypass

Midline or transverse abdominal incision CFA and branches exposed through groin incision Small bowel retracted to right Posterior peritoneum is open Retroperitoneal tunnels are made to groin. Heparin 5000U given iv bolus and vessels clamped


disease) Aorto-bifemoral bypass

Vertical incision on anterior aspect of Aorta Dacron sutured end to side (taking all the layers) The Limbs fed to the groin sutured end to side to

CFA Posterior peritoneum closed over peritoneum

Management Aorto-bifemoral bypass

Management Open Surgical Management (femoro-popliteal)

Open groin surgery CFA endarectomy + profundoplasty/ iliofemoral bypass

In case of added proximal (iliac) occlusion CFA endarectomy + profundoplasty / iliofemoral

bypass + iliac stenting

In case of added distal (SFA)occlusion CFA endarectomy + profundoplasty +SFA stenting/

femoropopliteal bypass


Endarterectomy Open:

When it involves short segment of big arteries Also called “dis-obliteration/ reboring” Heparin 5000U given pre-opeartively Artery is exposed after placing clamps Distal clamp applied first Longitudinal incision taken oven the occlusion till the

plaque is reached

Management Open Surgical

Management Endarterectomy

Open: Plane created

between plaque and media

The plaque is removed with the diseased intima

In case of thrombus, it is removed

Closed with non absorbable fine

sutures directly or a vein graft

Post op anticoagulant therapy with warfarin


Endarterectomy Closed

Artery exposed and clamped Proximal and distal transverse incisions taken Plane created between plaque and tunica media Wire loop passed from distal to lower arteriotomy

insion, stripping the plaque Can be used in relatively longer occlusions


Endarterectomy Balloon

Artery is exposed after clamping Proximal arteriotomy is made Fogarty ballon catheter is passed


Management Endarterectomy

Passed beyond the obstruction

Ballon is inflated Pulling the catheter

removes the atheroma

More commonly used for emboli (as they are comparetively loosely

adherant)


Profundoplasty Repairing of profunda femoris Arises posterior to CFA The vessel is dissected out and clamps are applied Arteriotomy extending from CFA to distal to

occlusion Atherectomy is then performed


Management Profundoplasty

Defect is them closed by a vein patch

On table angiography is then performed to check for patency

May be done in adjunct to bypass

surgeries


Femoro-popliteal bypass In patients with SFA and popliteal artery occlusion with a

distal segment of patent popliteal artery. In continuity with any crural artery Longitudinal groin incision to access the CFA Popliteal artery is exposed medially from thigh or the leg In above knee bypass, incision proximal to the knee to

access popliteal artery In below knee bypass, popliteal fossa is opened

Management Femoro-popliteal

bypass Polpileat vein is held

in Silastic loops Graft is tunnelled

and placed at the anastomotic site

Sephanous vein graft can be used In situ (requires

desruption of valves) Reversed, can be

accessed by a parallel skin incision


Infrapopliteal bypass Disease involving popliteal artery and proximal tibial

arteries. the target artery must have luminal continuity with

the foot Stenosis upto 50% is accepted as patent for surgery Calcification also not considered a contra-indiaction. SFA or Popliteal artery is used for “inflow”


Infrapopliteal bypass Access to PTA with dissection and separation of Soleal

muscle attachment from tibea access to PTA and PA Access to ATA with anterolateral incision on

legseparation of ant tibial muscle and external longus muscle ATA. Separation of interosseus membrane for tunneling of the graft.

Small veins can be used for anastomosis Or PTFE graft can be used


Other bypassesA. Axillofemoral graft

Tunnelled subcutaneously between the axillary artery proximally, to reachone or both CFA

Low patency ratesB. Femoro-femoral crossover bypass

Crossover graft by tunnelling a prosthetic graft subcutaneously above the pubis between the groins

Management

Management Endovascular management

Basically involves gaining access into transmural space via percutaneous femoral artery puncture

Balloon angioplasty Subintimal angioplasty Stenting Stent graft Variations of balloon angioplasty


Balloon angioplasty Guide wire is negotiated through the stenosis or

occlusion Then a balloon is inflated to open the occlusion It is kept inflated for approx 1 minutes with high

pressure then deflated May be combined with stenting


Balloon angioplasty Very good results for dilating the iliac and

femporopopliteal segments Below knee procedures are less successful 98% success in CLI (extremely good results) Limb salvage rate of 91% over 5 fyrs Failure in TASC D patients


Subintimal angioplasty Creating an arterial dissection purposely

begenning at the proximal end of the oclusion The guide wire is made to re-enter the lumen at

the diastal end of occlusion Use of balloon angioplasty to increase the

diameter of the false lumen Poor results 3 yrs patency rates being only 30% But good for critical limb ischemia


Subintimal angioplasty


Stenting If the vessel fail to remain dilated use stents Stainless steel stents May be introduced on a balloon catheter and

placed in position Self expanding stents (nitinol), which expand on

withdrawing the sheath Angioplasty (balloon) + stenting > primary

stenting But primary stenting > only angioplasty Poor results in TASC D patients


Stenting


Stent garft Expanded PTFE (ePTFE) with external nitinol stent Inner surface bonded with heparin Extremely flexible Can close conform to the shape of artery (esp: SFA) Self expanding stents Easier with better patency rates than atherectomy. It is easier, with more better technical succes

comapred t o PTA Few studies show similar results comapred to bypass

Management Endovascular

management Cutting balloon

Originally designed for coronary arteries

The balloon has three or four atherotomes or micro-surgical blades

These are mounted longitudinally on the balloon

The blades score the lesion and dilate the lesions


Cryoplasty Apoptosis by cooling Designed by Polar Cath Peripheral Dilatation

System (Boston Scientific) Balloon filled with nitrous oxide gas To cool to -10 degrees C Supposed to prevent restenosis


Endovascular atherectomy Excision atherectomy catheters remove and collect the

atheroma Ablative atherectomy device fragment it Rotational cutters turn at the speed of 8000rpm to shave the

plaque and collect in a storage chamber Laser atherectomy has a cold tipped laser that delivers burst

of ultraviolet Xenon energy in short pulse durations

Results same as balloon angioplasty


Endovascular atherectomy

Rotational cutter Laser tipped

Management Amputation

Indication for amputation Dead Limb

Gangrene Deadly Limb

Wet gangrene Spreading cellulitis

Dead Loss Limb Severe rest pain with Ischemia Paralysis Contracture


Choice of amputation Below knee amp[utation (BKA) Above knee amputation (AKA Ray amputation Transmetatarsal amputation Miscellaneous

Syme’s Chopart’s Lisfranc’s


Level of amputation Skin perfusion pressure >=40 mmhg Transcuatneous oxygen pressure >= 30mmhg

Predictors for Transmetatarsal amputation: Toe Blood Pressure >=30 mmhg Ankle Blood Pressure >= 80 mmHg


Below Knee Amputation Above Knee Amputation

Poor Healing Better Healing

More chances of revision/ healing by secondary intention

Less chances of revision

Better ambualtion Poor ambulation


Ray amputation


A. Syme’s B. Chopart’sC. Lisfranc’sD. Transmetatarsal

THANK YOU

chronic lower limb ischemia

Healthcare

open surgical

intermittent

popliteal

retrograde

phosphodiasterase

plane created

knee bypass

tasc ii