Influence of stent implantation on erythrocyte aggregation in human native coronary arteries and saphenous vein grafts.

OBJECTIVE: Stent implantation into atherosclerotic coronary vessels induces the release of particulate debris and soluble vasoactive substances, which impair downstream microvascular function. Microvascular perfusion, however, is also determined by hemorheological parameters. We therefore analyzed now changes in erythrocyte (RBC) aggregation in coronary arterial blood during stent implantation. METHODS: Symptomatic male patients with stable angina pectoris and stenosis in their native right coronary artery (RCA) or saphenous vein graft on right coronary artery (SVG-RCA) were enrolled. Coronary arterial blood was taken before and coronary aspirate during stent implantation with a distal occlusion/aspiration device. RBC aggregation was determined using the erythrocyte adhesiveness/aggregation test. The ratio of clot-free area to whole area of a spread blood drop was quantified (rCFA). To evaluate the impact of soluble factors within aspirate plasma on RBC aggregation, separated RBCs of healthy volunteers were exposed to patients' coronary arterial blood and aspirate samples. RESULTS: rCFA was comparably increased in coronary aspirate of RCAs and SVG-RCAs after stent implantation (RCA: 25.7±2.1% vs 32.2±2.1%; SVG-RCA: 28.9±1.9% vs 33.3±2.0%, P<.01). The rCFA of healthy volunteers was increased after adding coronary aspirate plasma. CONCLUSIONS: Stent implantation into atherosclerotic coronary arteries induces an increase in RBC aggregation, potentially contributing to impaired microvascular perfusion.