NEW YORK (Reuters Health) – Among patients with atrial fibrillation undergoing mechanical valve replacement, performing a concomitant Maze procedure during surgery reduces the rate of subsequent thromboembolic events, a Korean study has shown.
However, the benefit was limited to low surgical-risk patients, the researchers found. “These findings suggest that the approach for individual patients should be tailored according to their projected risks of surgical mortality/morbidity,” they conclude in their report in Circulation online March 28.
Dr. Jae Won Lee, at the University of Ulsan College of Medicine in Seoul, and colleagues explain that the Maze procedure to interrupt aberrant conduction pathways is effective for restoring normal sinus rhythm in AF patients and has become a popular adjunct to surgery for structural heart disease.
However, they continue, there is still concern that it may increase surgical risks by prolonging cardiac ischemic time, and benefits may be limited anyway in patients receiving mechanical replacement valves.
The team therefore looked at outcomes in 569 patients with AF-associated valvular heart disease who underwent mechanical valve replacement. A concomitant Maze procedure was performed in 317 of the patients and not in the other 252.
Median follow-up was 63.6 months. After adjustment for baseline characteristics, patients who had undergone a Maze procedure were at significantly lower risk of thromboembolic events (hazard ratio 0.29; p=0.008) than those who had valve replacement only, the investigators report.
On further analysis, the difference in the overall event rate was shown to be significant only in patients with a low-to-intermediate EuroSCORE risk (p=0.049), not in those with a high-risk EuroSCORE (p=0.65).
On echocardiographic assessment at a median of 52.7 months after surgery, tricuspid valve function and left ventricular function were significantly better in the Maze group than in those who did not have the procedure.
However, these benefits did not translate into better overall survival or event-free survival. The risk of death was similar in both groups (hazard ratio 1.15; p=0.63), as was the composite outcome of death, heart failure or valve-related complications (hazard ratio 0.82; p=0.42), Dr. Lee and colleagues found.
In summary, they write, “Conclusions regarding a comparison of ‘valve replacement alone’ and ‘valve replacement plus the Maze procedure’ in these patients await the results of prospective randomized trials.”