Thursday, June 24, 2010

Prosthetic-Valve Dehiscence

A 33-year-old man with rheumatic heart disease presented with an acute onset of chest pain. Five years earlier, the patient had undergone replacement of the mitral and aortic valves (Medtronic Hall and ATS Medical, respectively).

On physical examination, he had diaphoresis with normal vital signs and without evidence of congestive heart failure, acute aortic regurgitation, or abnormal prosthetic heart sounds. Electrocardiography that was performed 4 hours after the onset of pain showed ST elevation in left-sided leads V8 and V9, which was suggestive of inferoposterior myocardial injury. Laboratory evaluation revealed an elevated international normalized ratio (>12; normal range, 2.5 to 3.5), a creatine kinase level of 39 U per liter (normal range, 0 to 150), a creatine kinase MB level of 5.5 U per liter (normal range, 0.6 to 6.3), and a troponin I level of 0.24 ng per milliliter (normal range, 0.01 to 0.03).

Cardiac catheterization showed that the prosthetic aortic valve was significantly displaced with each heartbeat (Panels A and B, arrows); no abnormality of the mitral valve was observed. The patient underwent urgent excision and replacement of the dehisced aortic valve, which was found to be infected with Staphylococcus aureus, with associated vasculitis; the mitral valve was not affected. The patient had postoperative mediastinal bleeding and died from irreversible shock 24 hours later.