Prosthetic valve obstruction at Tygerberg Hospital between January 1991 and February 2001
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Background: Prosthetic valve obstruction is a relatively rare, but potentially fatal complication in patients with prosthetic heart valves. The diagnosis and appropriate management of these patients present a challenge to both the cardiologist and the cardiac surgeon. Despite efforts over the last 30 years to prevent this complication, it remains a lifelong risk. Obstruction is caused by pannus formation, thrombus formation or a combination of pannus and thrombus. Valve replacement has traditionally been the treatment of choice. Methods: Patients were selected from echocardiography and surgical reports between January 1991 and February 2001. All patients were analysed with regard to demographic information, clinical features, imaging results, treatment and outcome data. INR values on presentation were obtained from haematology archives. Results: A total of 32 patients presented on 34 occasions. There were 25 women and seven men. Obstruction occurred in the mitral position in 56% of cases and in the aortic position in 44% of cases. All but two valves were St Jude bileaflet valves. Patients generally presented with severe dyspnoea (NYHA class IV in 64.7%) and poor anticoagulation control (INR < 2.5 in 75.8%). The initial imaging modality used in all cases was transthoracic echocardiography. Fluoroscopy was used in five cases and transesophageal echocardiography in only two cases. Valve replacement was performed on 20 patients, six patients received thrombolysis and the remaining eight patients did not receive any treatment. Outcome was poor with an overall mortality of 64.7%. Conclusions: Given the extremely high mortality rate with current management, the treatment of prosthetic valve obstruction with thrombolysis in selected patients deserves consideration in a prospective study.