Forearm arterial compliance during reactive hyperemia and atherosclerosis risk factors

The arterial compliance increase occurring during reactive hyperemia is impaired when atherosclerosis risk factors, such as hypercholesterolemia, smoke and hypertension, are present. A new non-invasive plethysmographic method for assessing this endothelial dysfunction was developed and validity and clinical applicability explored. Simultaneous recordings of forearm pulse volume (FPV) and blood pressure (BP) were used to establish the FPV/BP relationship. Forearm arterial compliance (FAC) was measured by computing the dV/dP ratio; the area under the FAC/BP curve (FAC(AUC)) was also determined. The arterial occlusive test was performed in 93 subjects by an upper arm pressure cuff inflation, 30 mmHg above the SBP for 3 minutes. The time-course curve of compliance changes during reactive hyperemia was obtained by continuous measurements of F AC(AUC) for 20 seconds before and for 300 seconds after cuff deflation. The technique reliably assesses arterial compliance changes during reactive hyperemia; the analysis of time-course curves also allows to estimate a number of time-dependent parameters. On multivariate analysis, pre-ischemic FAC(AUC) was mainly affected by sex; peak-FAC(AUC) by sex and SBP and percent-changes by plasma levels of HDL-C (directly) and LDL-C (inversely). Peak-time was affected by age and BMI, whereas the descent-time was negatively affected by plasma triglyceride levels. The proposed technique is highly sensitive and can be considered as a useful tool to detect and monitor in vivo the effect of atherosclerosis risk factors on compliance changes induced by arterial occlusion.