Background: Peripheral arterial disease (PAD) accounts for one of the major clinical manifestation of atherosclerosis. It is strongly associated with increased risk of major cardiovascular events. The easiest accurate non-invasive method for the diagnosis of PAD is the measurement of ankle-brachial index (ABI). However, the standard Doppler method of ABI determination is not readily available.Thus, measuring ABI thru palpation can be considered an alternative method in general practice. This study was done to determine the accuracy of the ABI measured by palpation in comparison with the gold standard ABI measured by Doppler device in determining presence of PAD.
Methods: This is a validity study conducted at Philippine Heart Center (PHC). ABI by palpation method was done by the researcher while ABI by Doppler method was done by another physician. Measurements were done independently. Measures of validity of ABI by palpation in the diagnosis of PAD against the standard of ABI by Doppler method were statistically determined.
Results: There were 125 adult study subjects with at least one atherosclerosis risk factor, with one subject who had an above the knee amputation of the left lower extremity, making 249 extremities available for ABI determination. The diagnosis of PAD by palpation has a high sensitivity of 90.4%, specificity of 86.1 %, positive predictive value of 76.5% and an excellent negative predictive value of 94.7%. There is a weak agreement in the level of severity of PAD as obtained by these two methods. (K=0.466, p=O.OO).
Conclusions: ABI by palpation has been validated as a simple, non invasive means of determining ABI without the use of special equipment. This method is good for detecting the presence of PAD but is limited by the poor correlation of the degree of severity' with that obtained by Doppler method. Systematic evaluation of ABI by palpation can be incorporated to the physical examination list. Identification of patients possibly affected by PAD or those whose ABI cannot be measured by palpation warrants further evaluation by Doppler ultrasound and prompt referral to a vascular specialist.