Noninvasive evaluation of endothelial activity in healthy and diseased individuals.

Background: Diminished endothelial activity (EA) has been associated with an increased risk of incident cardiovascular disease (CAD) events.

Methods: Vasodilatory responses (EA and relative distensibility [RD]) were evaluated noninvasively using iontophoresis of acetylcholine (ACH) and sodium nitroprusside (SNP) and recorded by laser Doppler fluxmetry (LDF) and photoplethysmography (PPG) among 324 patients.

Results: The EA after ACH iontophoresis measured by LDF was significantly higher in the younger (<50 years) group than in the older (>50 years) group, 125.4 versus 103.3 integrated arbitrary unit (P < .005). Compared to the older patients, the EA values recorded by LDF were significantly lower in patients with diabetes mellitus (64.9), hypercholesterolemia (83.3), hypertension (88.7), CAD (61.0), and peripheral artery disease (67.4). The findings of RD were similar.

Conclusions: The results indicate that measuring EA using the iontophoresis of ACH or SNP and combined with either LDF or PPG is a viable approach that can discriminate between different clinical groups.