Peripheral Arterial Disease Westley Smith MD

Vascular Fellow

Background

(per 10,000) Goodney P, et al. Regional intensity of vascular care and lower extremity amputation rates. JVS. 2013; 6: 1471-1480.

Background

Goodney, P. et al. Variation in the Use of Lower Extremity Vascular Procedures for Critical Limb Ischemia. Circulation. 2012;5:94-102

Background

• Approximately 2 million living amputees

• Primary cause being PVD

• Nearly 200,000 new amputations every year

• Amputation associated hospital costs 2009 were $8.3 billion dollars

Classification

• Claudication

• Rest Pain

• Tissue Loss

Classification

• Claudication • Most commonly calf pain ranging from fatigue to aching while walking

• Less commonly thigh or buttock pain with or without impotence (Leriche’s)

• From ischemic neuropathy involving unmyelinated sensory fibers and anaerobic muscular acidosis

• Reproducible

• Alleviated by rest

Classification

• Claudication • Disease Location

• Single level most common from iliac or SFA (MC)

• Inflow disease: Aorto-iliac disease (supra-inguinal)

• Outflow disease: femoral to pedal vessels (infra-inguinal)

• Multi-level disease less common

Classification

• Critical Limb Ischemia • Rest pain

• Burning sensation, uncomfortable coldness, paresthesia improved with dependent positioning of forefoot

• Associated with high risk of limb loss without revascularization

• Tissue loss usually result of repetitive tissue trauma, mild though it may be in the setting of inadequate perfusion to allow healing

• Ischemic Gangrene occurs with resting limb blood flow is insufficient to maintain cellular viability

Classification

• Critical Limb Ischemia • Usually requires presence of two or more levels of disease

• Most commonly two sequential vascular beds i.e. femoral-popliteal & tibial

• Less commonly parallel vascular beds i.e. SFA & PFA

Epidemiology

• Natural History of Disease • Edinburgh Arterial Study: Age matched patients to those with normal ABI >

0.9 had increased risk of mortality. Further augmentation of lifestyle to alleviate symptoms demonstrated a worsened prognostic factor.

• McDermott found women me be more likely to alleviated symptoms with lifestyle changes and ultimately more rapid decline and poorer prognosis

• Cardiovascular Health Study (1993): 4705 participants with depressed ABI’s found to have an increased risk mortality from MI and stroke as MET’s achieved decreased

Epidemiology

• Prevalence Based on Risk Factors

Norgen et al: TASC II Working-Group, Inter-Society Concensus for Management of Peripheral Vascular Disease. JVS 45; S9A, 2007

Epidemiology

• Impact of Claudication on Extremity: • only 1 of 4 claudicants will progress to Critical Limb Ischemia. At risk factors

included insulin dependent DM, and failure to stop smoking. Overall risk of progression to amputation ~5% over a 5 year period

• Impact of Critical Limb Ischemia • 40% Limb loss

• 20% mortality 6 months from onset

Norgen et al: TASC II Working-Group, Inter-Society Concensus for Management of Peripheral Vascular Disease. JVS 45; S9A, 2007

Diagnosis

• History & Physical Exam • Differentiate vascular etiologies and non-vascular / neurogenic etiologies

• Focused pulse exam

• Risk Factors • Age, HTN, DM, CKD, HLD, Smoking

• Atypical presentation consider atypical risk factors • Hypercoagulable disorders, Aneurysms, Embolic sources ,Popliteal

Entrapment

Diagnosis

• Initial Hematologic Studies • Characterize risk factors and identify end organ damage (MC creatinine)

• CBC, glucose, A1c, Creatinine, HLD

• Hypercoagulable Disorders • Coagulation Panel, Protein C & S, Factor V, AT III, Anticardiolipin, fibrinogen,

Lupus assay, homocysteine

• Vascular Lab Studies

Diagnosis

• Vascular Laboratory and Imaging • Ankle Brachial Index and Segmental Pressures with toes pressures

• Pulse Volume Recording

ABI Severity

1.0-1.4 normal

0.9-1.0 abnormal

.6-.9 mild

.4-.6 moderate

.<.4 severe

Diagnosis

• Duplex imaging • B Mode

• Velocities and Waveforms

Gerhard-Herman M, et al. Guidelines for Noninvasive Vascular Laboratory Testing: A Report from the American Society of Echocardiography and the Society of Vascular Medicine and Biology. Journal American Society of Echocardiography;19:955-972. 2006

Diagnosis

• MRI/MRA • Aorto-iliac and femoral-popliteal disease MRA is equal to Digital Subtraction

Angiography

• Infrapopliteal disease Non-contrast MRI superior to MRA because of venous artifact, but DSA superior to non-contrast MRI

Diagnosis

• CTA • Timing bolus dependent

• Generally good Aorto-iliac imaging

• More limited tibial imaging

• Artifacts secondary to Calcified vessels

Diagnosis

• Angiography – The Gold Standard

Diagnosis

Modality Advantages Disadvantages

ABI Quick, no radiation, easily repeated Multilevel disease difficult, poorly localizing, unreliable in calcified vessels

Duplex Some retroperitoneal capabilities, quick, some role for specific delineation

Technically dependent, multilevel disease challenging

MRI Improved RP capabilities, no radiation, contrast and non-contrast capabilities

multilevel disease may be difficult, in stent restenosis limited, expensive, timely

CTA Quick, readily accessible Image quality and artifact limiting, radiation exposure

DSA Treatability Radiation, invasive, expensive

Non-Invasive Treatment

• Considerations of both disease process/symptoms and functionality/health of patient must be considered when deciding on medical management vs revascularization

• Smoking Cessation • Improved by physician assistance at 5 years from 5% to 22% • Buproprion, Varenicline

• Diabetes Management • Each 1% increase in HbA1c may increase risk of PVD by 28% • 2016 American Diabetic Association recommends HbA1c level 6.5

• HTN • Current BP recommendations 140/90 in high risk groups including PAD • Tighter management of 130/80 in DM and CKD patients • ACE inhibitors may provide some cardiovascular protectiveness, but overall BP reduction

seems most beneficial

Non-invasive Treatment

• High Cholesterol levels >200mg/dL, low HDL levels <40, and high LDL levels >130 have demonstrated increased cardiovascular risk • Stabilize existing plaques • Minimize oxidative stress • Reduce vascular inflammation • PAD disease benefits of statins have been limited to sub-group analyses with view

independently designed PAD studies • American Heart Association recommends LDL<100 in PAD patients and <70 in

patients with well known more systemic atherosclerosis

• Hyperhomocysteinemia • Promotes endothelial dysfunction and platelet aggregation • Supplementation with B vitamins and folate • However failure of high dose folate therapy proof to be cardio protective

Non-invasive Treatment

• Antiplatelet Therapy • Antiplatelet Trialist Collaboration: demonstrated fatal and non-fatal absolute

reduction of 2.5% benefit for those on anti-platelet therapy

• CAPRIE trial: ASA vs Plavix demonstrated benefit in secondary prevention in patients with known cardiovascular those taking Plavix over ASA with concomitant PAD (relative risk reduction 24%)

• Other Antiplatelet medications with ongoing studies – some not yet available in US

Non-invasive Treatment

• Exercise Therapy for Claudication

Non-Invasive Treatment

• Medications Specific for Claudication • Several not available in US

• Or no longer approved

Non-Invasive Treatment

• Medications Specific for Claudication

The old and the new