Role of Tibial Acceleration Time in Predicting Limb Salvage in Critical Limb Ischemia

Introduction: The role of acceleration time in predicting limb salvage in critical limb ischemia is recently well described in the literature. Ankle-brachial index (ABI) is the traditional test for the diagnosis of lower extremity peripheral artery disease (PAD) and assessment of its severity while Duplex ultrasound (DUS) is used to localize the vascular lesion. ABI has a limited role in diabetic patients because of wall calcification, so it gives inaccurate readings. The place of DUS with waveforms (DWs) analysis to estimate distal perfusion remains poorly known even if many consider it a helpful tool to evaluate PAD severity through distal perfusion. Aim: To assess the role of Tibial Arteries Acceleration Time (TAT) measurement in the assessment of distal perfusion and in predicting healing in patients undergoing revascularization of the foot in critical limb ischemia. Methods: Duplex ultrasound was done for 40 consecutive adult patients with critical limb ischemia. All patients underwent a Doppler study with ultrasound. The study includes a color Doppler map and pulse wave Doppler for all lengths of the lower limbs concentrated on CFA, SFA, POPA, ATA, and PTA, the following measurement are recorded included PSV, EDV, and AT for the distal parts of PTA and ATA. The patients were categorized into different groups according to AT; class I AT = 40-120 ms, class II AT= 121- 180 ms, class III AT = 181 – 225, and class 1V AT more than 226 ms. Catheterization was done for those patients. After angioplasty, a second session of Doppler study of the affected limb was done, recording distal arterial PSV, EDV, and AT. Results: In this study, we found a significant correlation between Acceleration Time improvement and the clinical healing of patients. Limb salvage as complete improvement was achieved in 19 of 40 (47.5%), partial improvement was achieved in 8 of 40 (20%), and no improvement was seen in 13 of 40 (32.5%). Complete and partial improvement was seen in class I AT and class II AT and no improvement in class III AT and IV AT. Conclusions: Tibial Acceleration Time demonstrates a high correlation with clinical improvement in patients with critical limb ischemia and can be used as a prognostic predictor for limb salvage after revascularization.