No evidence for increased intraoperative bleeding in aortic-valve stenosis: A comparative analysis of haemotherapy in 136 patients undergoing aortic-valve replacement

Abstract

Objective — An association of aortic-valve stenosis and abnormal bleeding, particularly from gastrointestinal angiodysplasia, has been reported. In this setting, high-shear stress generated by the transvalvular gradient leads to a conformational change of plasmic von Willebrand factor, making this adhesive protein more susceptible for proteolytic cleavage. Consequently, highest-molecular weight multimers of the von Willebrand factor are degraded through a von Willebrand factor specific protease leading to impaired platelet-related haemostasis.

Methods and results — To assess the role of aortic-valve stenosis as a factor predicting abnormal intraoperative bleeding in patients suffering from aortic-valve stenosis, we compared the number of intraoperatively administered blood components during aortic-valve replacement for aortic-valve stenosis (n = 50), aortic-valve insufficiency (n = 19) and combined aortic-valve defects (n = 67). As a result, the three subgroups did not differ significantly regarding the mean number of transfused red-blood cell units (0.94 ± 1.36, 0.4 ± 0.9, or 0.86 ± 1.3, respectively) and plasma units (0.04 ± 0.28, 0.21 ± 0.71, or 0.15 ± 0.61, respectively). None of the patients received platelet concentrates. A multivariate logistic regression model adjusted for age and gender did not show an influence of the presence and severity of aortic-valve stenosis on intraoperatively applied haemotherapy.

Conclusion — Along with our findings, the presence or severity of aortic-valve stenosis does not predict an increased need for intraoperative transfusion of blood components. Thus, this cardiac defect does not seem to represent a major risk determinant for intraoperative bleeding despite the high prevalence of shear-stress induced von Willebrand factor abnormalities in this setting.

• Aortic-valve stenosis
• acquired von Willebrand syndrome
• intraoperative bleeding
• haemotherapy