Acute Thrombotic Obstruction of a Mitral Valve Prosthesis: The Role of Thrombolytic Therapy

An acute thrombotic occlusion of a mitral prosthesis in a hemodynamically compromised patient was successfully lysed with intravenous streptokinase. Unfortunately, the patient had a major cerebral embolus, from which she died several days later. A review of the current literature reveals that thrombolytic therapy successfully relieves the obstructing thrombus in 73% of cases, while it is partially successful in another 16% allowing deferral of surgical repair to a more optimal time. Mortality from thrombolytic therapy is 14% while hemorrhage or cerebral emboli occur in a further 11%. Reports of surgical intervention have shown an operative mortality rate of 25%, in those fit to undergo surgery. If hemodynamically unstable patients unfit for surgery are included on an intention to treat basis, overall mortality is 42%. Thus, thrombolytic therapy should be considered primarily in those compromised patients who have a thrombotic occlusion of a valvular prosthesis with a greater risk of operative mortality. Low dose, prolonged infusions should be favoured over rapid, high concentration infusions currently employed for coronary thrombolysis, as the latter regime could have contributed to the fatal cerebral embolus in our patient.