The relation between endothelial dependent flow mediated dilation of the brachial artery and coronary collateral development - a cross sectional study.

Background: Endothelial dysfunction is thought to be a potential mechanism for the decreased presence of coronary collaterals. The aim of the study was to investigate the association between systemic endothelial function and the extent of coronary collaterals.
Methods: We investigated the association between endothelial function assessed via flow mediated dilation (FMD) of the brachial artery following reactive hyperemia and the extent of coronary collaterals graded from 0 to 3 according to Rentrop classification in a cohort of 171 consecutive patients who had high grade coronary stenosis or occlusion on their angiograms.
Results: Mean age was 61 years and 75% were males. Of the 171 patients 88 (51%) had well developed collaterals (grades of 2 or 3) whereas 83 (49%) had impaired collateral development (grades of 0 or 1). Patients with poor collaterals were significantly more likely to have diabetes (p = 0.001), but less likely to have used statins (p = 0.083). FMD measurements were not significantly different among good and poor collateral groups (11.5 +/- 5.6 vs. 10.4 +/- 6.2% respectively, p = 0.214). Nitroglycerin mediated dilation was also similar (13.4 +/- 5.9 vs. 12.8 +/- 6.5%, p = 0.521).
Conclusion: No significant association was found between the extent of angiographically visible coronary collaterals and systemic endothelial function assessed by FMD of the brachial artery.