Angiotensin converting enzyme inhibition; a potential new therapy for peripheral arterial disease

Abstract

Introduction: This randomised, double-blind, placebo controlled trial examines the effect of angiotensin converting enzyme (ACE) inhibition with ramipril for 24 weeks on walking ability and quality of life in patients with peripheral arterial disease (PAD).

Hypothesis: Ramipril therapy for 24 weeks will lead to significant improvement in pain free walking time (PFWT) and maximum walking time (MWT) and quality of life in this patient population.

Methods: A total of 343 patients were screened and to date 160 PAD patients have been randomized to receive ramipril, 10mg once daily or placebo for 24 weeks. Clinical walking distance was assessed via a standard exercise treadmill test at a speed of 3.2km/hr and grade of 12% and PFWT and MWT were determined. The ankle-brachial index (ABI) was also measured before and immediately following the exercise test. In addition, the standard Walking Impairment Questionnaire (WIQ) and the SF-36 questionnaire were administered to quantify walking ability (0=inability, 100= no difficulty) and quality of life respectively.

Results: The baseline characteristics of participants are presented below. Values are Mean (SEM) unless specified otherwise. Age , Mean (SD) 65.0 (7.8) Female Sex, No. (%) 31 (19.4) Body Mass Index, kg.m-225.5 (0.4) Diabetes Mellitus, No. (%) 58 (36.3) Statin Therapy, No. (%) 69 (43) Antiplatelet Therapy, No. (%) 57 (35.6) Ex Smokers, No. (%) 93 (58) Current Smokers, No. (%) 30 (18.8) Systolic Blood Pressure, mmHg 135.6 (2.2) Diastolic Blood Pressure, mmHg 78.9 (1.9) Mean Arterial Pressure, mmHg 89.6 (1.4) Heart Rate, beats per min 72.4 (2.0) ABI 0.56 (0.02) PFWT, sec 130.8 (7.7) MWT, sec 229.3 (11.6) Walking Impairment Score Distance 11.2 (1.7) Speed 12.6 (1.4) Stair Climbing 27.2 (2.0) Short-form 36 physical functioning 38.5(10.4) score

Conclusions: Completion of data collection and analysis for this trial is anticipated by June 2011. If positive this trial will validate ramipril as an efficacious new therapy for PAD.