PECAM-1/Thrombus Ratio Correlates with Blood Loss during Off-Pump Coronary Artery Bypass Grafting (OPCAB) Surgery: A Preliminary Study

Abstract

Platelet endothelial cell adhesion molecule 1 (PECAM-1) is considered an antiplatelet molecule. Previously, we introduced a new parameter called the PECAM-1/thrombus ratio, which indicates the proportion of PECAM-1 in the thrombus and provides a precise description of human platelet activity (in vitro). The aim of this study was to determine whether the PECAM-1/thrombus ratio could serve as a predictive factor for bleeding events during off-pump coronary artery bypass grafting (OPCAB). To achieve this, we collected blood samples from 20 patients scheduled to undergo OPCAB surgery. We assessed the PECAM-1/thrombus ratio by evaluating thrombus formation on collagen fibers under flow conditions. Subsequently, we compared the ability of the PECAM-1/thrombus ratio in predicting bleeding risk with other methods that evaluate hemostasis activity. These methods included assessing platelet P-selectin secretion, platelet exposure of phosphatidylserine, plasma coagulation and fibrinolysis system activity, and thrombus formation using the T-TAS assay. Our findings revealed a positive correlation between the PECAM-1/thrombus ratio and the amount of blood component units transfused (BCUT) during the OPCAB surgery. Furthermore, BCUT did not show any significant correlation with other measured hemostasis parameters. This preliminary study suggests that the PECAM-1/thrombus ratio might be a good predictor of bleeding risk during the OPCAB procedure.

Keywords: OPCAB; PECAM-1; bleeding; fibrin; fibrinolysis; platelet; thrombus.

Figure 1

Correlation between MPV and BCUT; n = 20.

Figure 2

Correlation between PECAM−1/thrombus ratio and BCUT; n = 20.

Figure 3

Representative pictures from confocal microscopy of thrombus formed on the collagen fibers in the flow chamber. Left (red): platelet PECAM-1 visualized with human anti-PECAM-1 antibody. Middle (green): thrombus composed of platelets visualized with DiOC6(3). Right (merged): the overlapped pictures of platelet PECAM-1 and thrombus. Bar = 10 µm.

Figure 4

Representative pictures from flow cytometry. The upper panel shows platelets that undergo P−selectin secretion. Before platelet activation (on the left), only one platelet population is seen. After activation (on the right), platelet population with secreted P−selectin appears (indicated with red arrow). The bottom panel shows platelets that undergo PS exposure. Before platelet activation (on the left), only one platelet population is seen. After activation (on the right), platelet population with exposed PS appears (indicated with red arrow).

Figure 5

Representative picture from confocal microscopy of fibrin net in clot formed after recalcification of PPP. Bar = 10 µm.