Association between peripheral endothelial function and myocardial perfusion in patients with coronary artery disease.

Aims: Endothelial dysfunction is a systemic disorder and risk factor for atherosclerosis. Our aim was to assess whether there is a relation between peripheral endothelial function and myocardial perfusion in patients with coronary artery disease (CAD). Methods and results: We prospectively studied 54 patients, who had a positive result for obstructive CAD in coronary CT angiography. Myocardial perfusion (15O)H2O positron emission tomography was imaged at rest and during adenosine-induced maximal vasodilation. Peripheral endothelial function was assessed by measuring flow-mediated dilation (FMD) with ultrasound from the left brachial artery. There was a statistically significant correlation between FMD and global hyperaemic myocardial blood flow (MBF; r = 0.308, P = 0.023). The correlation remained statistically significant when controlling for gender, height, and diastolic blood pressure at rest (r = 0.367, P = 0.008). Receiver operating character analysis, however, yielded an area under curve of only 0.559 (P = 0.492) when FMD was used to predict reduced MBF (below 2.3 mL/g/min). Patients with significantly decreased MBF (n = 14) underwent invasive coronary angiography. FMD showed an inverse correlation with the severity of the most significant stenosis (r = -0.687, P = 0.007). Conclusion: Peripheral endothelial function is related with hyperaemic MBF and with the severity of CAD in invasive coronary angiography. Due to insufficient sensitivity and specificity in the identification of reduced MBF, FMD is not suitable for clinical practice at the individual level. However, it works at the population level as a research tool when assessing endothelial dysfunction in patients with CAD.