The effects of cardiopulmonary bypass on systemic and coronary levels of von Willebrand factor.

Abstract

Von Willebrand factor antigen (vWF Ag) is a marker of endothelial injury which has been shown to rise during surgical procedures, including cardiopulmonary bypass (CPB). The aim of this study was to determine whether intermittent aortic cross-clamping during CPB causes the release of vWF Ag from the coronary vascular bed, which would suggest coronary vascular endothelial cell perturbation. Fifteen consecutive patients undergoing CPB with aortic cross-clamping during coronary artery bypass surgery and/or valve replacement by the same surgeon were studied. Paired venous and coronary sinus samples were taken pre- and post-thoracotomy, prior to cross-clamping on CPB, and 1, 5 and 10 minutes after release of the aortic cross-clamp. Plasma vWF Ag (IU/ml) was measured by ELISA. Venous vWF Ag measured prior to skin incision was 0.75 +/- 0.11 IU/ml (mean +/- SEM) and fell to 0.53 +/- 0.07 IU/ml after institution of CPB but prior to aortic cross-clamping (P < 0.01 vs pre-incision sample). Coronary sinus vWF Ag measured prior to aortic cross-clamping was 0.54 +/- 0.06 IU/ml (P = NS vs paired venous sample). At 1, 5 and 10 min after release of the aortic cross-clamp there was a progressive rise in vWF Ag in both venous and coronary sinus samples (1 min: 0.67 +/- 0.05 IU/ml vs 0.75 +/- 0.10 IU/ml, 5 min: 0.73 +/- 0.07 IU/ml vs 0.76 +/- 0.09 IU/ml, 10 min: 0.74 +/- 0.08 IU/ml vs 0.79 +/- 0.09 IU/ml; P = NS venous vs coronary sinus, respectively). Levels of vWF Ag were highest immediately prior to the termination of CPB (venous: 0.95 +/- 0.12 IU/ml; coronary sinus: 0.91 +/- 0.14 IU/ml). We conclude that cardiac surgery using CPB with aortic cross-clamping is associated with a progressive rise in coronary sinus and venous levels of vWF Ag.(ABSTRACT TRUNCATED AT 250 WORDS)