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CLINICAL STATEMENTS AND GUIDELINES

June 11, 2024 Circulation. 2024;149:e1313–e1410. DOI: 10.1161/CIR.0000000000001251 e1322

Table 4.  Clinical Subsets of Patients With PAD Clinical Subset Description/Characterization Asymptomatic PAD (may have functional impairment) Depending on the population assessed and method of assessment, 20%-59%1–4 of patients with objectively proven PAD report no leg symptoms.

Patients classified as having asymptomatic PAD may self-limit and adapt their activity to remain below their ischemic threshold to avoid leg pain. A significant percentage of patients with asymptomatic PAD who report no exertional leg symptoms develop symptoms during an objective walking test.5 The prevalence of asymptomatic PAD varies depending on whether patients are recruited from a primary care or community setting (lower %) vs a vascular laboratory (higher %).3 Patients with PAD who are asymptomatic have functional impairment comparable to patients with claudication.1,6,7 Associated with increased risk of MACE, including mortality.8,9

Chronic symptomatic PAD (includes claudication and other ischemia-related exertional leg symptoms) Most common clinically evident subset of PAD; patients report claudication or other nonjoint-related exertional leg symptoms that can limit walking performance.

Exertional leg symptoms (typical claudication or other) reported in up to 80% of patients with objectively proven PAD, depending on case series.1–3 Includes ischemia-related exertional leg symptoms, not present at rest, generally increasing with progressive exercise intensity and quickly relieved by rest (within 10 min).10 Typical claudication symptoms may be described as a pain, aching, cramping, or tired/fatigued feeling located in the buttocks, thigh, calf, or foot that occurs consistently during walking, does not start at rest, does not improve during walking, and is usually relieved within approximately 10 min of rest.1–3,11 Leg symptom descriptors also include tingling, numbness, burning, throbbing, or shooting.12–15 For some patients, exertional leg symptoms due to PAD are not typical of claudication because they may not limit walking or may take >10 min to resolve after rest.11 Chronic symptomatic PAD is associated with significant functional (walking) impairment, regardless of whether symptoms are typical of claudication.1,6,7

CLTI Severe clinical subset of PAD.

Among patients with known PAD, incidence of CLTI estimated to be between 11% and 20%.16–18 Manifests as ischemic rest pain, nonhealing wounds/ulcers, or gangrene with symptoms present for >2 wk.19 Responsible for most major and minor limb amputations related to PAD.16,17 Historically estimated 1-y mortality rate of 25%-35% and 1-y rate of amputation up to 30% among patients presenting with CLTI.20,21 Lower rates of mortality and amputation reported in a recent RCT of patients with CLTI undergoing revascularization.22 Ischemic rest pain often affects the forefoot and is worsened with limb elevation and relieved by dependency. Among vascular specialists, the Fontaine23 and Rutherford24 classification systems are most commonly used to categorize severity of CLTI. The WIfI classification estimates risk of lower extremity amputation according to wound extent, severity of ischemia, and presence of foot infection and has been shown to correlate with clinical outcomes.19,25–28

ALI Severe clinical subset of PAD.

In a contemporary RCT of patients with symptomatic PAD who were observed for a mean of 30 mo, the incidence of ALI was 1.7%, or 0.8/100 patient-y.29 Previous lower extremity revascularization, atrial fibrillation, lower ABI values associated with increased risk of ALI in this population. Sudden decrease in arterial perfusion of the leg that threatens the viability of the limb. Acute clinical symptoms (<2 wk duration) include pain, pallor, pulselessness, poikilothermia (coolness), paresthesias, and potential for paralysis.20,24,30 Causes of ALI include embolism, thrombosis within native artery or at site of previous revascularization (graft or stent), trauma, peripheral aneurysm with distal embolization, or thrombosis (Table 20). Timing of presentation may vary depending on the underlying etiology.20 The status of the leg in ALI is further classified according to the Rutherford classification system.20,24,30 Class I. Viable (limb not immediately threatened)—No sensory loss; no motor loss; audible arterial and venous Doppler signals. Class IIa. Salvageable/marginally threatened (limb salvageable if promptly treated)—Mild-to-moderate sensory loss (limited to toes) but no motor loss, often inaudible arterial Doppler but audible venous Doppler signals. Class IIb. Salvageable/immediately threatened (limb salvageable if urgently treated)—Sensory loss involving more than the toes; mildmoderate motor weakness. Inaudible arterial but audible venous Doppler signals. Class III. Irreversible (major tissue loss or permanent nerve damage inevitable)—Complete sensory loss (anesthetic); complete loss of motor function (paralysis); inaudible arterial and venous Doppler signals.

ALI indicates acute limb ischemia; CLTI, chronic limb-threatening ischemia; PAD, peripheral artery disease; RCT, randomized controlled trial; and WIfI, wound, ischemia, and foot infection.

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