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Late complications of aortic valve replacement with cloth-covered, composite-seat prostheses. A six-year appraisal
Insights
Warfarin significantly reduces thromboembolic complications in patients with cloth-covered aortic prostheses. Antiplatelet drugs have not yet proven sufficient for preventing these adverse events.
Area of Science:
- Cardiovascular Surgery
- Biomaterials Science
Background:
- Cloth-covered composite-seat aortic prostheses are widely used.
- Assessing long-term safety and efficacy is crucial for patient outcomes.
Purpose of the Study:
- To evaluate the early and late results of cloth-covered aortic prostheses.
- To compare thromboembolic complication rates with and without warfarin.
- To investigate the incidence of strut cloth wear.
Main Methods:
- Advanced actuarial techniques applied to a cohort of 396 patients.
- Analysis of postoperative warfarin use versus no warfarin.
- Examination of explanted prostheses for wear at reoperation.
Main Results:
- Warfarin use in 116 patients with Model 2310-2320 prostheses resulted in zero thromboembolic complications over 360 patient-years.
- Patients with the same prosthesis but without warfarin experienced 9 emboli per 100 patient-years.
- Cloth wear was observed in 10 patients, a complication addressed by the Model 2400 composite strut valve.
Conclusions:
- Concomitant anticoagulant therapy, specifically warfarin, significantly enhances the safety of cloth-covered aortic valves.
- The efficacy of antiplatelet agents alone has not been established for these prostheses.
- The Model 2400 valve design mitigates strut cloth wear.
Abstract:
Advanced actuarial techniques are used to analyze early and late results in a closely followed series of 396 patients who received a cloth-covered, composite-seat aortic prosthesis. Late mortality and various complications are carefully assessed, and most late deaths are seen to be unrelated to the prosthesis. One hundred sixteen patients with Model 2310-2320 prostheses who received warfarin postoperatively had no thromboembolic complications in 360 patient-years of follow-up (average, 3.1 years per patient); 134 patients who had the same prosthesis but did not receive warfarin had 9 emboli per 100 patient-years (average follow-up, 1.7 years per patient; total, 228 patient-years). By comparison, in 9 years' experience with non-cloth-covered Model 1200-1260 valves, 132 patients had 4.0 emboli per 100 patient-years (average follow-up, 5.1 years; total, 673 patient-years). The safety of cloth-covered valves is clearly enhanced by concomitant use of anticoagulants; the possibility that antiplatelet drugs may suffice has not yet been demonstrated. Strut cloth wear was found at reoperation in 10 patients. The Model 2400 composite strut ("track") valve with a narrow metal track on the inner surface of each strut prevents this complication.