Background: Thrombus formation is one of the main pathogeneses of acute coronary syndrome with atherosclerotic rupture. Previous studies have reported that atherosclerosis increases platelet aggregability and that vascular endothelial dysfunction reflects early change of atherosclerosis. However, the relationship between coronary endothelial dysfunction and platelet reactivity remains unclear. Therefore, in this study, we investigated the relationship between them in non-obstructive ischemic heart disease (IHD) patients.
Methods: Three hundred sixty-eight consecutive stable patients with suspected angina presenting non-obstructive coronary arteries (<50% diameter) in coronary angiography were investigated with the intracoronary acetylcholine provocation test and measured adenosine triphosphate-induced coronary flow reserve. Finally, 25 non-obstructive IHD patients who had no anti-platelet agents were assessed for the relationship between coronary blood flow volume (CBFV) change and platelet aggregability as P2Y12 reaction unit (PRU) by VerifyNow P2Y12 assay system.
Results: CBFV change by intracoronary 20 μg/kg per minute acetylcholine provocation showed a significant negative correlation with platelet aggregability as PRU (r = 0.44, P = 0.03). Conversely, there was no significant correlation between PRU and endothelial function as coronary flow reserve. Furthermore, multivariable linear regression analysis indicated that an incremental CBFV change was independently associated with PRU (β = 0.63, P < 0.001) in non-obstructive IHD patients.
Conclusions: In patients with non-obstructive IHD, CBFV change was significantly associated with platelet aggregability, indicating that coronary endothelial dysfunction might mediate higher platelet aggregability.
Keywords: Coronary blood flow volume; Endothelium; Platelet aggregability.
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