Abstract
Abstract
Background
The transradial approach is commonly preferred over the femoral approach for coronary angiography to reduce vascular complications like bleeding, aneurysm formation and all-cause mortality ensuring early ambulation after coronary procedures. However, there is growing evidence that damage to the radial artery endothelium elicits intimal hyperplasia, vascular remodeling and might ultimately lead to total vessel occlusion.
Objective
Our study aimed to investigate the effects of dietary flavanol intervention on (a) early endothelial functional recovery and (b) late structural changes i.e. intimal hyperplasia after mechanical vascular wall injury in the human forearm model during coronary angiography.
Methods
Radial artery flow-mediated vasodilation (RA-FMD), local stiffness (fractional diameter change, Fdc), intima-media thickness (IMT), luminal and external arterial diameter at the site of intervention and the contralateral control artery were measured in 38 male patients (19 flavanol intervention, 19 placebo control) undergoing transradial coronary angiography (TCA) at baseline, after 7 days of 450mg flavanol supplementation BID, directly after TCA and 6 months after TCA. Circulating levels of endothelial microparticle (EMP) subpopulations CD31+/41-, CD62e+and CD144+were analyzed simultaneously as a surrogate for endothelial functional integrity and activation.
Results
One week of flavanol supplementation, not placebo, significantly increased RA-FMD (8.88±2.03% vs. 11.17±2.89%, p<0.01 in flavanol and 8.64±1.87% vs. 8.32±1.63%, p=n.s. in placebo). RA-FMD significantly decreased in the intervention artery directly after TCA, which was partly mitigated by flavanol supplementation (delta to baseline: −2.61±0.82% in flavanol vs. −4.91±0.63% in placebo, p=0.034). TCA induced significant intimal hyperplasia in the radial artery (0.36±0.02mm vs. 0.44±0.04mm, p<0.01) in placebo, but not in the flavanol group (0.36±0.02mm vs. 0.37±0.02mm, p=n.s.) after 6 month. One week of flavanol supplementation increased Fdc (1.94±0.99 vs. 3.07±1.31, p<0.01). No changes occurred in the placebo group (1.99±1.29 vs. 1.96±1.17, p=n.s.). On the contralateral arm, the decrease in RA-FMD was blunted by flavanols (delta to baseline: +0.42±1.05% in flavanol vs. −0.61±1.55% in placebo) along with decreased circulating levels of EMPs.
Conclusions
TCA impairs endothelial function (RA-FMD), vascular physicomechanics (Fdc) and induces intimal hyperplasia (IMT). Periinterventional flavanol supplementation blunts the acute decreases in endothelial function and physicomechanics and prevents chronic negative vascular remodeling.