Clinical Characteristics and Angioplasty Outcomes in Lower Extremity Artery Disease Patients with Normal Ankle-Brachial Index: A Clinical Conundrum.

Background: The resting ankle-brachial index (ABI) is widely used to diagnose lower extremity artery disease (LEAD). However, some LEAD patients have a normal ABI yet require percutaneous transluminal angioplasty (PTA).

Methods: This was a retrospective study of consecutive LEAD patients who underwent PTA. The patients were classified into two groups based on the ABI of the limb that underwent PTA: the ABI-normal group (ABI 0.91-1.40), and ABI-abnormal group (ABI ≤ 0.90 or > 1.40). The primary endpoints were major adverse cardiovascular and cerebral events (MACCEs) and major adverse limb events (MALEs).

Results: Of the 334 patients (mean age: 70 ± 12 years, 60% male), 69 (21%) had a normal ABI, and 265 (79%) had an abnormal ABI. After a median follow-up of 1.5 (0.6-3.1) years, 84 (25%) patients reached the primary or secondary endpoints. The ABI-normal group had a higher proportion of males (73% vs. 57%, p = 0.02) and a higher prevalence of chronic kidney disease (78% vs. 56%, p < 0.01). Angiography revealed less severe lesions in the femoropopliteal artery (p < 0.01) and a lower rate of stent deployment (15% vs. 31%, p < 0.01) in the ABI-normal group than in the ABI-abnormal group. However, the incidence rates of MACCEs (29% vs. 24%, p = 0.56) and MALEs (23% vs. 28%, p = 0.63) were comparable in the two groups.

Conclusions: LEAD patients with a normal ABI often have less severe above-the-knee artery lesions but similar poor outcomes, highlighting the need for additional hemodynamic assessments and increased clinical attention.