Registered Physician in Vascular Interpretation (RPVI) Practice Exam

The key idea is that an ABI can be falsely elevated when the ankle arteries are noncompressible due to medial calcification. This is common in diabetes (and can occur with chronic kidney disease and aging). When the vessels are stiff from calcification, the cuff cannot compress the arteries properly, so the measured ankle systolic pressure is higher than the true pressure. The result is an ABI that looks normal or only mildly elevated even though there could be significant arterial disease. An ABI of 1.2 fits this scenario best in a patient with diabetic calcified vessels, making the elevation suspicious for a false reading. In a normal healthy leg, such a value would be less likely; after exercise, ABI may actually decrease transiently, and in acute arterial occlusion the ABI would be markedly low, not falsely elevated.