Stroke risk is highest in the first month following mitral valve replacement with a bioprosthesis, suggesting a potential need for more aggressive early anticoagulation.
All patients (285) undergoing mitral valve replacement (MVR) with a Carpentier-Edwards (C-E) bioprosthesis +/- coronary bypass grafts (CABG) were reviewed (109 men and 176 women with a median age of 70 years). Overall, the 5-year survival rate was 58.9%, 62.7% for MVR (199 patients) and 50.1% for MVR+CABG (86 patients). Late survival was adversely affected by the operative time variables of NYHA class IV, older (> or = 70 years) age, low (> or = 56%) ejection fraction (EF), and the additional performance of associated procedures+CABG with MVR (P < or = 0.001). The 5-year freedom from stroke rate was 89.2%, 89.1% for MVR and 90.2% for MVR +/- CABG. Advanced heart class was the only significant variable associated with a greater risk of late stroke (P < or = 0.01). Neither chronic preoperative atrial fibrillation nor operative obliteration of the left atrial appendage increased or decreased the late risk of stroke in patients following MVR. Hazard function for stroke occurring in the first postoperative year (first 48 h excluded to discount intraoperative events) demonstrated the highest rate within the first month (40%), rapidly diminishing thereafter. This pattern was reproduced in the 12-year hazard function in that the rate of stroke occurrence was greatest in the first year (6.7%) following implantation. The mean stroke rate over 12 years was 2.5%. Strokes following MVR +/- CABG are more likely to occur in older and more compromised patients, and the higher early rate is not reflected in the mean rate. A more aggressive approach to early anticoagulation with IV heparin, Coumadin, and possibly antiplatelet therapy is advocated to reduce this complication rate.
Orszulak et al. (Sun,) studied this question.