Loss of High-Molecular-Weight Multimers Is Not Associated with Increased Postoperative Bleeding after Surgical Aortic Valve Replacement

Background: Patients with severe aortic stenosis (AS) show an association with “von Willebrand factor” (VWF) multimer abnormalities. Especially, the loss of high-molecular-weight multimers (HMWMs) could affect primary hemostasis resulting in postoperative bleeding. Analysis of VWF multimers remains challenging. Thus, the aim of our study was to analyze the incidence of acquired von Willebrand syndrome (aVWS) and to investigate the correlation between echocardiographic parameter and altered VWF multimer structures with respect to postoperative bleeding after surgical aortic valve replacement (SAVR).

Method: We prospectively included 52 patients (age: 67.9 ± 7.2 years; 53.8% male) with severe AS admitted for SAVR. According to VWF abnormalities, patients were divided in two groups (A: abnormal VWF multimer, n = 24; B: normal VWF multimer, n = 28). Blood samples and echocardiographic data were collected one day before SAVR (time point 1), 7 days (time point 2) after SAVR, and 3 months (time point 3) after SAVR. Blood loss and the use of blood and hemostatic agents were evaluated perioperatively.

Results: Baseline and preoperative data were similar in both groups. After SVAR, the level of HMWM was significantly increased. While 20% of all patients still had a loss of HMWM at time point 2, HMWM normalized after 3 months. Postoperative bleeding occurred in nearly 15% (A: 16.7% vs. B: 14.3; p > 0.999) with the need of rethoracotomy in ~10% (A: 8.3% vs. B: 10.7%; p > 0.999). There was no significant difference in postoperative bleeding in the first 24 hours (A: 491.2 mL vs. B: 700.7 mL; p = 0.255). Also, intra- and postoperative need of blood transfusion and hemostatic agents were similar between the groups. Group A showed a higher platelet count on day 7 after surgery (A: 258.8 × 109/L vs. B: 220.9 × 109/L; p = 0.0434). HMWM was inversely correlated with the peak aortic gradient (R = −0.557; p < 0.001) and positively correlated with the aortic valve area (R = 0.292; p = 0.04).

Conclusion: Loss of HMWM was not associated with increased perioperative blood loss in patients with severe AS. Altered VWF multimers were restored three months after SAVR. Echocardiographic parameters could predict the loss of HMWM. The HMWM as a rapid and sensitive assay and echocardiography could therefore contribute to initial screening of VWF multimers in the diagnostic algorithm of aVWS.

Publication History

Article published online:
03 February 2022