Perioperatieve veranderingen in de microvasculaire perfusie in patiënten die coronaire bypass chirurgie ondergaan.

The endothelial glycocalyx (EGC) is a gel-like layer that acts as a natural coating for endothelial cells, thereby preventing these cells from having direct contact with circulating blood cells. In order to reduce the inflammatory and procoagulant response during cardiopulmonary bypass in patients undergoing cardiac surgery through contact activation, extracorporeal circuits are coated with a biocompatible surface. In VU University Medical Center, cardiopulmonary bypass is mostly performed using a heparin-coated extracorporeal circuit in combination with full anticoagulation by heparin administration. A heparin coated extracorporeal circuit might be more biocompatible with the endothelial glycocalyx, due to its comparable biochemical structure. Alternatively, a phosphorylcholine-coated extracorporeal circuit is used. The present study investigates whether the use of the heparin-coated extracorporeal circuit will contribute to the preservation of the glycocalyx during cardiac surgery, when compared to the phosphorylcholine-coated circuit.

The primary endpoint of this study is the change in perfused boundary region (PBR) during cardiopulmonary bypass (CPB). We assume that a heparin coated extracorporeal circuit, due to its comparable biochemical structure, is more biocompatible with the endothelial glycocalyx. Hence, the increase of PBR will be more pronounced with the use of a phosphorylcholine-coated extracorporeal circuit. Therefore, it is hypothesized that the use of the heparin-coated extracorporeal circuit is associated with less severe disturbances of the perfused boundary region than the phosphorylcholine-coated circuit.

Blood will be drawn and several microcirculatory imaging parameters will be measured before surgery (T0), before (T1) and after administration of heparin (T2), after initiation of CPB (T3), after placement of the side clamp (T4), after administration of protamine (T5), after infusion of concentrated red blood cells (T6), 3 hours after the patient has arrived at the ICU (T7), and 24 hours (T8) and 72 hours (T9) following surgery.

The endothelial glycocalyx (EGC) is a gel-like layer that acts as a natural coating for endothelial cells, thereby preventing these cells from having direct contact with circulating blood cells. In order to reduce the inflammatory and procoagulant response during cardiopulmonary bypass in patients undergoing cardiac surgery through contact activation, extracorporeal circuits are coated with a biocompatible surface. In VU University Medical Center, cardiopulmonary bypass is mostly performed using a heparin-coated extracorporeal circuit in combination with full anticoagulation by heparin administration. Alternatively, a phosphorylcholine-coated extracorporeal circuit is used, but it is unknown how these different biocompatible-coated extracorporeal circuits will contribute to the preservation of the glycocalyx during cardiac surgery.