Perioperative evaluation of primary hemostasis in patients undergoing mitral valve repair

INTRODUCTION No data exist on the prevalence of primary hemostatic defects and acquired von Willebrand disease in mitral valve prolapse with severe regurgitation. METHODS Primary hemostasis was evaluated by PFA-100, von Willebrand Factor Antigen (vWF:Ag) and Ristocetin cofactor (vWF:RiCof) assays in a prospective observational trial. Sixty-five consecutive patients with mitral regurgitation (study group) or aortic stenosis (control group) who were operated for mitral valve repair or aortic valve replacement were enrolled in the study. RESULTS There were no differences in Closure Time in the two groups at all time points. The concentration of plasma vWF: Ag was within normal limits in all patients preoperatively; after surgery, a significant increase was observed in both groups from baseline (199 +/- 144 mcg/dL vs. 295 +/-141 mcg/dL in the study group, p=0.002; 243 +/- 141 mcg/dLl vs 338 +/- 154 mcg/dL in the control group, p=0.009). The ratio of vWF:RiCof to vWF:Ag was slightly decreased preoperatively in both groups (ratio= 0.91) and showed a marked increase in the postoperative period (ratio=0.22) as, probably, new hemostatically effective large multimeric forms of vWF were released. CONCLUSIONS Patients who present for surgery with a valvular pathology with high shear stress have some degree of primary hemostasis defect; nevertheless, the potent stimulus of surgery and the correction of the underlying disease allow quick restoration of vWF activity and normalization of PFA-100.