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Early and late stroke after mitral valve replacement with a mechanical prosthesis: risk factor analysis of a 24-year
Ko Bando1, Junjiro Kobayashi, Mitsuhiro Hirata
1Department of Cardiovascular Surgery, National Cardiovascular Center, 5-7-1 Fujishirodai, Suita, Osaka, Japan. kobando@hsp.ncvc.go.jp
Insights
Persistent atrial fibrillation significantly increases stroke risk after mechanical mitral valve replacement. The maze procedure to restore sinus rhythm nearly eliminates this risk, outperforming left atrial appendage closure.
Area of Science:
- Cardiovascular Surgery
- Cardiac Electrophysiology
- Medical Statistics
Background:
- Mechanical mitral valve replacement is a critical procedure for severe mitral valve disease.
- Stroke is a significant complication following mechanical mitral valve replacement, impacting patient outcomes.
- Identifying modifiable risk factors is crucial for improving long-term results.
Purpose of the Study:
- To evaluate risk factors for mortality and stroke after mechanical mitral valve replacement.
- To assess the impact of concomitant procedures on stroke risk.
- To determine predictors of long-term survival and freedom from stroke.
Main Methods:
- A retrospective analysis of 812 patients undergoing mechanical mitral valve replacement between 1977 and 2001.
- Cox proportional hazards models were used to identify predictors of mortality and stroke.
- Actuarial survival and freedom from stroke were analyzed using log-rank tests.
Main Results:
- Five-year survival was 91.1%.
- Sinus rhythm was associated with significantly better freedom from stroke compared to atrial fibrillation (P <.001).
- The maze procedure, combined with mitral valve replacement, resulted in 99% freedom from stroke at 8 years, versus 89% for mitral valve replacement alone. Persistent atrial fibrillation (OR, 3.39) and omission of the maze procedure (OR, 3.40) were significant risk factors for late stroke.
Conclusions:
- Persistent atrial fibrillation is the primary risk factor for late stroke post-mechanical mitral valve replacement.
- Implementing the maze procedure to restore sinus rhythm effectively mitigates the risk of late stroke.
- Left atrial appendage closure and anticoagulation did not prevent stroke in this cohort.
Objective:
We evaluated risk factors for mortality and stroke after mechanical mitral valve replacement between May 1977 and December 2001.
Methods:
Early and late mortality and stroke were assessed. Potential predictors of mortality and stroke were entered into a Cox proportional hazards model. Actuarial survival and freedom from stroke were determined by a log-rank test.
Results:
Mitral valve replacement was performed in 812 patients. Concomitant procedures included left atrial appendage closure in 493 (61%) patients, tricuspid annuloplasty-replacement in 348 (43%) patients, maze procedure in 185 (23%) patients, plication of the left atrium in 148 (18%) patients, and other procedures in 151 (19%) patients. Five-year actuarial survival was 91.1% +/- 2.3%. Freedom from stroke at 8 years was significantly better in patients with sinus rhythm versus atrial fibrillation (P <.001). Ninety-nine percent of patients with mitral valve replacement combined with a maze procedure were free from stroke, whereas only 89% of patients with mitral valve replacement alone were free from stroke at 8 years after surgical intervention. Seventy-two patients had late stroke; sixty-five patients (90%) were in atrial fibrillation, and 47 (65%) patients had the left atrial appendage closed. Multivariate analysis showed that late atrial fibrillation (odds ratio, 3.39; 95% confidence interval, 1.72-6.67; P =.0001) and omission of the maze procedure (odds ratio, 3.40; 95% confidence interval, 1.14-10.14; P =.003) were the significant risk factors for late stroke.
Conclusions:
Persistent atrial fibrillation was the most significant risk factor for late stroke after mechanical mitral valve replacement. Restoration of sinus rhythm with a maze procedure nearly eliminated the risk of late stroke, whereas neither closure of the left atrial appendage nor therapeutic anticoagulation prevented this complication.