If both pulses on both feet are normal and there are no femoral bruits, there is a less than 10% chance of an ABI being abnormal in a study population with a prevalence of disease of 28%. I could not make any other conclusions from this article.
1619 patients who has undergone peripheral arterial testing between December 2005 and February 2010. Excluded:
- 228 due to an abnormally high ABI (greater than 1.30) in either leg
- 155 patients because the examination for femoral bruit was not recorded
- 1 patient because the examination for distal pulses was not recorded
- ABI <= 0.9
- 1236 patients (2472 legs)
- API was abnormal in at least on leg of 348 patients (28%)
- 575 patients had a normal clinical examination (no femoral bruits and both pulses on both feet normal) and 546 of these (95%) has normal ABIs. I calculate the confidence interval is 92.75 % to 96.54 %.
- The authors state that a complete clinical examination has a sensitivity and specificity of 58.2% and 98.3%; however, I cannot reproduce these numbers. The problem may be due to the authors inconsistently reporting number of patients versus number of legs and also not clearly stating whether an abnormal examination is when any one finding is abnormal or when all findings are abnormal.
Armstrong DW, Tobin C, & Matangi MF (2010). The accuracy of the physical examination for the detection of lower extremity peripheral arterial disease. The Canadian journal of cardiology, 26 (10) PMID: 21165366