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Thrombotic obstruction of the Björk-Shiley valve: the Glasgow experience
Insights
Thrombotic obstruction is a serious complication of Björk-Shiley tilting disc prostheses, particularly in mitral valve replacements. Inadequate anticoagulation and poor exercise capacity are identified risk factors.
Area of Science:
- Cardiovascular Surgery
- Biomaterials Science
Background:
- The Björk-Shiley tilting disc prosthesis was widely used for heart valve replacement.
- Thrombotic obstruction represents a significant feared complication associated with mechanical heart valves.
Purpose of the Study:
- To investigate the incidence and risk factors of thrombotic obstruction in Björk-Shiley tilting disc prostheses.
- To determine the mortality associated with this complication and reoperation.
Main Methods:
- A retrospective analysis of 1186 Björk-Shiley valves implanted in 900 patients between 1971 and 1982.
- Long-term follow-up of 807 patients for 4146 patient-years, with identification of thrombotic events at autopsy or reoperation.
Main Results:
- Nineteen cases of thrombotic obstruction were identified, with a higher incidence in mitral valve replacements (0.79/100 patient-years).
- The overall incidence was calculated at 0.46/100 patient-years, with a maximum possible incidence of 1.4/100 patient-years.
- Mortality rates were high: 41.7% for reoperation and 63% for the complication itself.
Conclusions:
- Thrombotic obstruction is a critical complication of Björk-Shiley valves, especially in the mitral position.
- Inadequate anticoagulation, poor preoperative exercise capacity, and small prosthesis size are identified risk factors.
- High mortality underscores the need for careful patient selection and management.
Abstract:
Thrombotic obstruction is the most feared complication of the Björk-Shiley tilting disc prosthesis. From 1971 to 1982 1186 Björk-Shiley valves were implanted in 900 patients. There were 93 deaths in hospital. Eight hundred and seven patients have been followed for a total of 4146 patient years; 14 patients were lost to follow up. Nineteen cases of thrombotic obstruction were identified at necropsy or at a repeat operation in the study group. The mitral prosthesis was thrombosed in 16 patients, the aortic in two, and the tricuspid in one. The incidence for this complication has been calculated to be 0.46 per 100 patient years for all valve positions, 0.79 for single mitral valve replacements, 0.18 for aortic replacements, and 0.63/100 for the tricuspid position. The maximum possible incidence of this complication in this population has been calculated to be 1.4 per 100 patient years. The mortality rate was 41.7% for reoperation and 63% for the development of the complication. Risk factors that have been identified are inadequate anticoagulant control, poor preoperative exercise capacity, and possibly also the implantation of small prostheses.