NEW YORK (Reuters Health) – When patients with atrial fibrillation receive a prosthetic valve, a simultaneous ‘maze’ procedure during surgery reduces the rate of subsequent thromboembolic events, a Korean study has shown.
In the maze procedure, the surgeon makes an intricate pattern of cuts in the atria, then stitches the incisions to produce scars to block the errant signals that lead to atrial fibrillation.
The benefit of the maze procedure in the new study was limited to low surgical-risk patients, however.
“These findings suggest that the approach for individual patients should be tailored according to their projected risks of surgical mortality/morbidity,” Dr. Jae Won Lee, at the University of Ulsan College of Medicine in Seoul, and colleagues wrote in Circulation online March 28.
They say the maze procedure has become a popular adjunct to surgery for structural heart disease. However, they continue, there is still concern that as an add-on procedure it could increase surgical risks by prolonging cardiac ischemic time, and its benefits may be limited anyway in patients receiving mechanical valves.
The team therefore looked at outcomes in 569 patients with AF-associated valvular heart disease who received new mechanical valves, including 317 who had a maze procedure done at the same time.
Median follow-up was 63.6 months. After adjustment for baseline characteristics, patients who had 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 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.”