Antistreptokinase antibodies and outcome of fibrinolytic therapy with streptokinase for left-sided prosthetic valve thrombosis.

BACKGROUND: Left-sided prosthetic valve thrombosis (PVT) is a serious complication of valve replacement. In developing countries, fibrinolysis with streptokinase (SK) is often used as the first line of treatment. Anti-streptokinase (anti-SK) antibodies are widely prevalent in the general population, but their effect on the efficacy and outcome of fibrinolysis with SK in patients with PVT is not known. METHODS: Patients with rheumatic heart disease and prosthetic valve replacement presenting with a first episode of left-sided PVT were enrolled. All patients underwent fibrinolysis with SK. An indirect enzyme-linked immunosorbent assay was used to detect anti-SK antibodies before fibrinolysis. Relationship of these antibodies to the outcome of fibrinolysis was evaluated. RESULTS: Forty-four patients treated for left-sided PVT were included. Thrombosis affected 33 mitral and 11 aortic prosthetic valves. On fibrinolysis with SK, 32 (73%) patients achieved complete success, whereas it was unsuccessful in the remaining 12 patients. There were 3 bleeding events, 1 stroke, and 3 deaths. Mean anti-SK antibody levels were not significantly different between patients who had complete success and those who did not (8.81 ± 2.43 vs 7.67 ± 1.26 Au/mL; P = .13) and did not correlate with the outcome after adjustment with other variables. Patients in New York Heart Association class III or IV had a greater chance of failed fibrinolytic therapy, even after adjustment for other prognostic variables (odds ratio 9.0; 95% CI 1.29-63.02; P = .027). CONCLUSION: Anti-SK antibody titers are not associated with success of fibrinolytic therapy using SK in patients with left-sided PVT.