Obstacles in Screening Below-the-Knee Arterial Lesions in CLTI Patients Using Doppler Ultrasound

Duplex ultrasound (DUS) is a noninvasive imaging modality increasingly used for the evaluation of lower extremity arterial disease. However, its diagnostic accuracy in below-the-knee (BTK) arteries among patients with chronic limb-threatening ischemia (CLTI) remains uncertain. This study aimed to evaluate the diagnoticic accuracy of DUS for detecting BTK artery lesions in patients with CLTI by comparing its findings with angiography.

This study aimed to evaluate the diagnostic accuracy of duplex DUS for detecting BTK arterial lesions in patients with CLTI by comparing its findings with angiography.

We retrospectively analyzed 233 newly diagnosed CLTI patients (Rutherford grades 4-6) treated between 2018 and 2022. DUS findings were compared with angiographic findings in femoropopliteal arteries (FPA) and BTK arteries. The primary outcome was concordance between DUS and angiography. Secondary analyses identified clinical factors influencing concordance.

The concordance rate for FPA was 82.0%, while BTK arteries showed significantly lower concordance: anterior tibial artery 52.9%, posterior tibial artery 58.6%, and peroneal artery 59.9% (all p < 0.001 vs. FPA). Factors associated with reduced concordance included older age, lean BMI, renal failure on dialysis, and FPA stenosis.

DUS demonstrates limited reliability in screening BTK lesions among CLTI patients, particularly in elderly or dialysis-dependent populations. Given these limitations, angiography should be performed to confirm DUS findings in high-risk groups to avoid underestimation of disease severity and inappropriate revascularization strategies. Recognizing key predictors of reduced DUS accuracy may help clinicians identify cases requiring confirmatory imaging and improve individualized diagnostic pathways in CLTI management.