Ankle Brachial Index as a Screening Test in Suspected Coronary Artery Disease Patients

Abstract

Abstract: The resting ankle- brachial index (ABI) is a non-invasive method to assess the
patency of lower extremity arterial system and to screen for the presence of peripheral occlusive
arterial disease. Diagnostic efficacy of ABI to predict atherosclerosis is well documented and
reduction in index (< 0.9) is indicative of generalized atherosclerosis. Present study was planned
to evaluate the role of ABI as a possible non- invasive marker for coronary atherosclerosis.
Objective: To evaluate the relationship between ABI and the extent of coronary artery disease
estimated by angiography.
Study design: Cross Sectional Study.
Settings: Departments of Medicine & Cardiology, Mayo Hospital, Lahore.
Duration:Six months, from July 2006 to January 2007.
Subjects: One hundred and fifty patients referred for coronary angiography were selected. ABI
was calculated on each patient before undergoing angiography. A single cardiologist using a
computer based quantitative coronary angiography made angiography interpretations.
Results: The mean age of patients was 51.23±10.23 years. There were 147 (98%) patients with
normal ABI (>0.9), 2 (1.3%) with mild reduction in ABI (0.7- 0.89), and 1 (0.7%) with moderate ABI
(0.4- 0.69). In patients with normal ABI 34 (22.7%) patients had normal coronary angiogram, 43
(28.7%) patients had single vessel disease, 33 (22%) patients had two vessels disease, 35
(23.3%) patients had three vessels disease, and 2 (1.3%) patients had four vessel disease. In
patients with mild ABI (0.7- 0.89) there was 1(0.7%) patient who had single vessel disease, and 1
(0.7%) patient with four vessel disease. In the moderate ABI category (0.4 - 0.69) there was 1
(0.7%) patient with two vessel disease.
Conclusion: Ninety eight percent of the studied population with otherwise symptomatic
coronary artery disease had normal ABI. On the other hand 77% of patients with normal ABI had
abnormalities on coronary angiogram. ABI lacks the sensitivity to screen atheromatous CAD and
cannot be recommended as such.