ASSESSMENT OF STENOSES IN THE AORTOILIAC TRACT BY CALCULATION OF A VASCULAR-RESISTANCE CHANGE RATIO BEFORE AND AFTER EXERCISE

Objectives: Intraarterial pressure measurement is the most reliable me thod to assess haemodynamically significant stenoses in the nortoiliac tract. We have tried to develop a simple and quick, non-invasive meth od to assess stenoses of this type. Design: Prospective semi-blinded c linical study. Methods: It was postulated that a haemodynamically sign ificant aortoiliac tract stenosis would result in a lesser degree of v ascular resistance decrease after vasodilatation, compared to patients only suffering from femorodistal stenoses. We approximated vascular r esistance by: (brachial pressure-ankle pressure)/femoral artery mean D oppler velocity. By dividing vascular resistance at rest by vascular r esistance after exercise, we calculated the Resistance Change Ratio (R CR). Patients and results: In 34 patients (50 legs) with arterial sten oses, the pressure gradient over the aortoiliac segment was compared t o the RCR. Legs were divided in three groups: group 1 consisted of 22 legs that showed a pressure gradient > 10 mmHg at rest; group 2 showed a pressure gradient > 10 mmHg after papaverine; group 3 showed a pres sure gradient of 10 mmHg or less. The median RCR was: 0.74 (range: 0.2 3-4.04) for group 1, 0.71 (range: 0.36-1.80) for group 2 and 0.93 (ran ge 0.36-2.06) for group 3. There was no significant difference between the groups (p = 0.19). Conclusion: The RCR could nor be used to accur ately detect stenoses in the aortoiliac.