DIAGNOSING PERIPHERAL ARTERIAL DISEASE IN PATIENTS WITH KNOWN CORONARY ARTERY DISEASE IN A TERTIARY CARE CENTER IN LAHORE AND ASSESSING DIAGNOSTIC ACCURACY OF ANKLE – BRACHIAL INDEX TAKING DUPLEX ULTRASOUND AS GOLD STANDARD

Abstract

Introduction

It is common for patients with PAD to have concomitant CAD because both are caused by atherosclerosis, a systemic process. This has been well established in international studies. The incidence of PAD in patients with known CAD in our population is unknown. The ankle – brachial index (ABI) can be calculated by taking the ratio of ankle systolic pressure and brachial systolic pressure. It is a simple, easy and cost effective bedside tool to diagnose peripheral arterial disease (PAD).

Objective:  The objective of the study was to:

• Determine the incidence of PAD in patients with known coronary artery disease (CAD) in our population.
• Determine the diagnostic accuracy of ABI in diagnosing PAD in patients with CAD taking dup-lex ultrasound as gold standard in local population.

Study Design:  Cross sectional study.

Setting:  Department of Cardiology (CCU), Jinnah Hospital, Lahore.

Study Duration:  Six months from 01 June 2014 to 31 December 2014.

Subjects and Methods:  310 patients who met the inclusion / exclusion criteria were entered in the study. Mercury sphygmomanometer was used to take the systolic blood pressure of all the four limbs, and the ratio of ankle systolic pressure (higher of systolic pressure taken in both left and right limb was taken) to brachial systolic pressure (higher of systolic pressure taken in both left and right limb was taken) was used to calculate the ABI. An abnormal ABI was conside-red if the ratio was < 0.9. All subjects underwent duplex ultrasound as a gold standard to detect the presence or absence of PAD.

Results:  Out of 310 cases, common age was calcula-ted as 59.21 ± 8.93 years, 53.23% (n = 165) were male while 46.77% (n = 145) were female, frequency of peripheral artery disease (PAD) on gold standard was recorded as 28.71% (n = 89), diagnostic accuracy of Ankle-Brachial Index (ABI) in diagnosing peripheral artery disease (PAD) in patients with coronary artery disease (CAD) was calculated as 93.25%, 94.21%, 86.46%, 97.20% and 93.87% as specificity, sensitivity, negative predictive value, positive predictive value and accuracy rate respectively.

Conclusion:  There is a 28.7% incidence of PAD in patients with known CAD in our study population. The ABI is a simple, easy low cost and yet underutilized tool that can detect PAD with high diagnostic accuracy in this population.

Keywords:  Coronary artery disease (CAD), peripheral artery disease (PAD), diagnosis, ankle – bra-chial index (ABI), accuracy