High prevalence of hypercoagulable states in patients with recurrent thrombosis of mechanical heart valves

Background and aims of the study: Thrombosis is one of the most feared and life-threatening complications of mechanical heart valves (MHV), with an in cidence of 1-3 per 100 patient-years. Hypercoagulable states are highly pre valent in the general population and can predispose MHV to thrombus formati on. Thus, we conducted a study to investigate the frequency of hypercoagula ble states in patients with MHV who had recurrent thrombosis at least twice after valve implantation. Methods: Fifteen patients (mean age 42 +/- 11 years; range: 18 to 55 years) with recurrent thrombosis of MHV (2.4 +/- 0.8 recurrences/patient) (group 1) and 15 matched patients (mean age 40 +/- 12 years; range: 18 to 55 years ) with MHV without thrombosis (group 2) were followed up with transthoracic and transesophageal echocardiography. Patients' sera were monitored for an tibodies to cardiolipin (ACLA-IgG and ACLA-IgM), phosphatidylserine (APSA), lupus-type anticoagulant (LA) and lipoprotein(a) (LP(a)). Results: Average values for group 1 versus group 2 were: ACLA-IgG (normal r ange <15 GPLU/ml) 24.7 +/- 14.6 versus 6.2 +/- 2.7 (p<0.001); ACLA-IgM (<12 .5 MPLU/ml) 7.9 +/- 5.0 versus 3.3 +/- 1.7 (u = 185; p<0.001); APSA (<12 RL U/ml) 4.8 +/- 5.7 and 2.9 +/- 1.2 (p = 0.56); and LP(a) (<30 mg/dl) 36.5 +/ - 26.5 and 13.4 +/- 7.1 (p<0.001). The frequency of LA-positive cases was 4 /15 in group 1 and 0/15 in group 2 (p<0.05). The frequency of abnormally hi gh levels of ACLA-IgG was 9/15 in group 1 and 0/15 in group 2 (p<0.001); of ACLA-IgM, 2/15 in group 1 and 0/15 in group 2 (p>0.05); of APSA, 1/15 in g roup 1 and 0/15 in group 2 (p>0.05); and of LP(a), 5/15 in group 1 and 0/15 in group 2 (p<0.05). At least one of the factors included in this study wa s abnormal in 14 of 15 (93%) patients (p<0.0001). Conclusions: Hypercoagulable states are highly prevalent in patients with r ecurrent thrombosis of MHV. All patients evaluated for therapy of obstructi ve thrombosis of MHV should be investigated for hypercoagulable state. More over, in high-risk patients, surgical replacement of the MHV with a biopros thesis should be considered.