Diagnostic correctness of distal blood pressure measurements in patients with arterial insufficiency.

The value of distal blood pressure measurement by strain gauge technique in arterial insufficiency was analysed by means of the so-called direct method for evaluation of diagnostic tests, and by the calculation of the diagnostic specificity (predictive value of a positive test), the diagnostic sensitivity (predictive value of a negative test), and the diagnostic correctness (the proportion of patients correctly classified by the test). A blood pressure gradient greater than or equal to 20 mmHg from arm to ankle had a high diagnostic correctness as a screening procedure for arterial insufficiency among forty out-patients. Likewise, in sixty-seven patients admitted for arterial reconstruction a toe blood pressure < 30 mmHg had a high diagnostic correctness in deciding whether constant pain was in fact ischaemic rest pain. In contrast, distal blood pressure measurement was of no value as an indicator of the walking distance of claudicants or in locating the arterial obliterations. It is proposed, that similar evaluations are performed on other tests for arterial insufficiency.