The Beneficial Effect of Anticoagulation in Aortic Bioprosthesis is Associated with its Size.

Objective: To evaluate the clinical and echocardiographic outcomes in aortic valve replacement (AVR) patients with aortic bioprosthesis under oral anticoagulation (OA). Methods: Patients who underwent AVR with bioprosthesis were prospectively enrolled. They were classified based on postoperative use of OA. Clinical and operative variables were collected. Echocardiographic and clinical follow-ups were performed two years after surgery. The primary outcome evaluated was change in transprosthetic gradient. Secondary outcomes analyzed were change in New York Heart Association (NYHA) class, major bleeding episodes, hospitalization, stroke, and transient ischemic attack. Results: We included 103 patients (61 without OA and 42 with OA). Clinical characteristics were similar among groups, except for younger age (76 +/- 6.3 vs. 72.4 +/- 8.1 years, P=0.016) and higher prevalence of atrial fibrillation (0% vs. 23.8%, P<0.001) in the OA group. Mean (21.4 +/- 10 mmHg vs. 16.8 +/- 7.7 mmHg, P=0.037) and maximum (33.4 +/- 13.7 mmHg vs. 28.4 +/- 10.2 mmHg, P=0.05) transprosthetic gradients were higher in patients without OA. Improvement in NYHA class was more frequent in patients with OA (73% vs. 45.3%, P=0.032). Major bleeding, stroke, and hospitalization were similar among groups. OA was the only independent predictor for improvement of NYHA class after multivariate logistic regression analysis (odds ratio [OR]: 5.9, 95% confidence interval [CI]: 1.2-29.4; P=0.028). Stratification by prosthesis size showed that patients with <= 21 mm prosthesis benefited from OA. Conclusion: Early anticoagulation after AVR with bioprosthesis was associated with significant decrease of transprosthesis gradient and improvement in NYHA class. These associations were seen mainly in patients with <= 21 mm prosthesis.