Background: The aim of this study was first to compare the widely used flow mediated dilation ( FMD ) method with the iontophoretically induced acetylcholine vasodilation (IAV ) procedure. The ultimate goal was to examine the endothelial activity ( EA ) in patients with various cardiovascular risk factors compared with control subjects. Patients and methods: In the upper extremities of 27 subjects, comparisons of EA by FMD and IAV measured with laser Doppler flux method (LDF) were conducted. IAV-EA was then measured using LDF in an additional 93 subjects with various cardiovascular ( CVD ) risk factors and/or a diagnosis of coronary heart disease (CHD). Results: The mean age of the subjects was 56.2 years and 54% were male. There was a robust and significant correlation between FMD vs IAV endothelial activity (r = 0.87, p = 0.025). After adjustment for age, there were significant differences in LDF-measured, acetylcholine-induced EA by diagnosis of CHD (p = 0.02), hyperlipidemia (p = 0.03) and diabetes (p < 0.01), as well as by sex (p < 0.01). The difference by hypertension status was of borderline significance (p = 0.07). LDF EA was higher in non-smokers compared to smokers but this difference was not statistically significant (p = 0.3). After adjustment for age and gender, a 10-unit increase in LDF-measured EA was associated with a 12% lower odds for a diagnosis of CHD (p = 0.07). Conclusions: Measurement of IAV-EA by LDF is a simple, noninvasive methodology which is highly correlated with post-occlusive FMD EA and is also significantly associated with a diagnosis of CHD.
The impact of cardiovascular risk factors on the age-related excess risk of coronary heart disease
