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CLINICAL STATEMENTS AND GUIDELINES Circulation. 2024;149:e1313–e1410. DOI: 10.1161/CIR.0000000000001251 June 11, 2024 e1325 2a B-NR 10. In patients with CLTI with nonhealing wounds or gangrene, it can be useful to use toe pressure/ TBI with waveforms, TcPO2, SPP, and/or other local perfusion measures to determine the likelihood of wound healing without or after revascularization.13,14,28,33–36,38 Synopsis After the history and physical examination identify patients at risk for PAD and with history of physical examination symptoms or signs of PAD, diagnostic testing to establish the diagnosis of PAD is performed (Figure 2). The ABI, a simple, noninvasive physiological test, remains the cornerstone for initial diagnosis of PAD, although it has multiple limitations, particularly in the setting of diabetes and chronic kidney disease (CKD), which are associated with noncompressible vessels, and for the assessment of CLTI.39,40 The ABI may be performed in a vascular laboratory or in an office-based setting using a blood pressure cuff and a Doppler device. Continuous-wave Doppler waveforms or plethysmographic tracings (ie, PVR) at the ankle are performed. Beyond the ABI, additional physiological testing is performed in the evaluation of PAD to supplement the ABI and includes exercise ABI testing, segmental pressures, leg pressures and (PVR and/or Doppler) waveforms, toe pressure/TBI, and perfusion imaging. Imaging studies (see Section 3.2, “Imaging for PAD”) are performed when further definition of anatomy is required, such as to plan revascularization. The diagnostic approach to ALI is discussed separately in Section 11, “Acute Limb Ischemia.” Recommendation-Specific Supportive Text 1 The resting ABI is measured in each leg using a blood pressure cuff and a Doppler device to detect blood flow and pressure in the pedal and the brachial arteries.3,41 The ABI is the ratio of the higher systolic pressure in the ipsilateral dorsalis pedis and posterior tibial arteries divided by the higher of the left and right brachial artery systolic pressures.3,41 In patients with symptoms of PAD, the resting ABI has a sensitivity of 69% to 79% and a specificity of 83% to 99% compared with imaging studies showing significant arterial stenoses, although the sensitivity is reduced in the presence of diabetes.1–3,42,43 As an adjunct to ABI, Doppler waveforms and/or plethysmographic PVR taken at the ankle can confirm concordance with the presence and severity of PAD and suggest the presence of noncompressible arteries in the setting of discordance. 2 Standardized criteria for reporting the resting ABI allow for comparison between and within patients and from facility to facility and for changes in severity of disease within the same patient over time. These criteria for reporting ABI have been broadly adopted internationally.3,41 3 The ABI test is noninvasive, is simple to perform, and has minimal risks, making it suitable as a screening test for PAD among those at risk (Table 5). Patients with an abnormal ABI who are asymptomatic (asymptomatic PAD) have poorer cardiovascular morbidity and mortality outcomes than do patients with normal ABI.7–9,44–51 Beyond risk stratification, detection of PAD has potential treatment implications for asymptomatic PAD, including application of GDMT (see Section 5, “Medical Therapy and Preventive Foot Care for the Patient With PAD”). In an RCT of a vascular screening program in Denmark that assessed ABI, hypertension, and abdominal aortic aneurysm among men 65 to 74 years of age, the vascular screening program resulted in a small but statistically significant reduction in the overall mortality rate after a median of 4.4 years of followup.52 Because 3 screening tools were used, it is difficult to determine how much of the benefit was related to measuring the ABI. A separate RCT, also conducted in Denmark, of a more extensive cardiovascular screening program in men 65 to 74 years of age, that included ABI along with coronary and aortoiliac calcium CT assessment, cardiac monitoring, and blood cholesterol and glucose levels, did not find a mortality benefit of the screening program at a median of 5.6 years of follow-up.53 In addition to increased cardiovascular risk, asymptomatic patients with an abnormal resting ABI have a poorer functional status and a more rapid rate of functional decline than do patients with a normal ABI.4,54–58 Although physical activity has been shown to be associated with improvement in functional status in patients with asymptomatic PAD,59,60 the benefit of resting ABI testing to identify asymptomatic patients who may benefit from structured exercise programs remains to be determined. 4. The prevalence of PAD among individuals with- out risk factors for atherosclerosis and who are <50 years of age is low. Data from populationbased cohort studies have shown a low prevalence (approximately 1%) of abnormal resting ABI among individuals <50 years of age.10,11 In NHANES (National Health and Nutrition Examination Survey), approximately 95% of participants with an abnormal resting ABI had at least 1 risk factor for atherosclerosis.10 The yield of ABI testing among younger, asymptomatic individuals without risk factors for atherosclerosis is low, and these patients should not be routinely tested for PAD.10,11 Recommendations for Resting ABI and Additional Physiological Testing (Continued) COR LOE Recommendations Downloaded from http://ahajournals.org by on October 7, 2026