18 Oct

Antithrombotic Therapy in Mechanical and Biological Prosthetic Heart Valves and Saphenous Vein Bypass Grafts: Bioprosthetic Valves

Regarding the use of antiplatelet agents alone, in patients with a St. Jude valve, a few studies are completed, and the results are inconsistent (Table 4A). Some showed an incidence of thromboembolic events with antiplatelet agents between 2.1/100 patients/year and 3.2 patients/year, and these values were not different from some reports with anticoagulant ther-apy.37A37B On the other hand, some short case series have shown a high incidence of thromboembolic events (24% in 9 months; 12.5% in 4 years). When more than 1 valve was inserted, a high incidence of thromboembolic events was also shown.
Bioprosthetic Valves
Bioprosthetic valves are generally recognized to be less thrombogenic than mechanical valves. Nevertheless, anticoagulants and antiplatelet agents may be indicated in some instances. Among patients with bioprosthetic valves who received no anticoagulants after the early (3-month) postoperative period, the occurrence of thromboemboli among those with AF was 16% at 36 months, In patients in normal sinus rhythm, the thromboembolic rate was 10% at 36 months. A somewhat lower occurrence of thromboemboli in untreated patients who were in sinus rhythm was observed by others. A thromboembolic incidence of approximately 4% at 36 months and 12% at 108 months was observed in such patients. other

It has been reported that the incidence of thromboemboli in patients with bioprosthetic valves is higher in those who are in AF than in those in sinus rhythm. A 15% incidence of thromboemboli at 108 months has been reported in patients, most of whom were in AF and were treated with anticoagulants. Some, however, found the danger of anticoagulant therapy in patients with AF to exceed the risk of thromboemboli. The risk of thromboembolism in patients with AF seemed to be greatest in those with a history of previous emboli and in those with thrombi in the left atrium. Among patients with AF who did not have an enlarged left atrium or a history of previous embolism, thromboemboli occurred in only 2.4%.

Categories: Antithrombotic Therapy
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