ROLE OF SERIAL ANKLE-BRACHIAL PRESSURE INDEX (ABPI) AS A PROGNOSTIC TOOL TO PREDICT SUCCESS OF LOWER LIMB REVASCULARIZATION IN PAD/CLTI

Abstract

Background: Peripheral artery disease (PAD) and chronic limb-threatening ischemia (CLTI) lead to severe, life-threatening conditions, which include ulcers, gangrene, and even the loss of a limb. Although revascularization helps reverse these issues, predicting long-term success is difficult. Ankle-brachial pressure index (ABPI) measurement is a low-cost, risk-free option for detecting healing and predicting limb-saving success following lower limb revascularization.

Objectives: To evaluate the long-term probability of success of lower-limb revascularization and to find early hemodynamic markers associated with improved limb salvage. Focus on serial ankle-brachial pressure index measurements in PAD/CLTI patients.

Methodology: This prospective study was conducted Department of  Vascular Surgery CMH Peshawar from July 2024 to Dec 2024 over a six-month follow-up period. A total of 60 adult patients diagnosed with peripheral artery disease (PAD) or chronic limb-threatening ischemia (CLTI) and scheduled for lower-limb revascularization were enrolled. Inclusion criteria required age ≥18 years, Rutherford class 4–6 disease, and the ability to provide informed consent. Patients with non-compressible arteries (ABPI >1.30), acute limb ischemia, prior major amputation of the target limb, or incomplete hemodynamic data were excluded. All patients underwent standardized clinical evaluation, Doppler assessment, and appropriate imaging such as CT angiography or digital subtraction angiography prior to intervention. Revascularization was performed using endovascular angioplasty, stenting, surgical bypass, or hybrid techniques based on anatomical and clinical findings. Ankle-brachial pressure index (ABPI) was measured using a handheld Doppler and sphygmomanometer at baseline (pre-procedure), 48 hours post-procedure, one month, three months, and six months. The primary study outcome was successful limb salvage, defined as clinical improvement, wound healing, and absence of major amputation at six months. Secondary outcomes included restenosis, re-intervention, and mortality. Data analysis was performed using SPSS 24, employing paired comparisons, group analysis, logistic regression, and ROC curve assessment to identify prognostic ABPI thresholds.

Results: A total of 60 patients were included with a mean age of 60 ± 8.4 years. The baseline mean ABPI was 0.39 ± 0.11, increasing significantly to 0.71 ± 0.16 at 48 hours (p < 0.001), 0.76 ± 0.14 at one month, and 0.82 ± 0.13 at six months. Overall, 76.6% achieved successful limb salvage, while 10% required major amputation and 5% died during follow-up. Patients with successful outcomes demonstrated markedly higher early post-procedure ABPI and greater ΔABPI improvement throughout the follow-up period compared with those who failed revascularization. The mean ABPI at six months in the success group was 0.87 ± 0.10, compared with 0.54 ± 0.12 in the failure group (p < 0.001). Logistic regression identified post-procedure ABPI ≥ 0.70 and ΔABPI ≥ 0.30 as independent predictors of a favorable outcome. ROC analysis yielded an AUC of 0.83, demonstrating good discriminative ability of ABPI in predicting limb-salvage success. These findings confirm that both early and sustained ABPI improvement strongly correlate with healing, symptom relief, and reduced amputation risk after revascularization.

Conclusion: Serial ABPI measurement is a practical, inexpensive, and reliable prognostic indicator following lower-limb revascularization in PAD/CLTI. Early hemodynamic improvement and sustained elevation in ABPI strongly predict successful limb salvage and reduced amputation rates. A post-procedure ABPI ≥ 0.70 emerged as a key threshold associated with favorable outcomes. Incorporating serial ABPI into routine follow-up can enhance risk stratification and guide timely decisions for re-intervention when required.