Winter 2007

Early Mitral Valve Repair Promoted

UCSF cardiac surgeon Scot Merrick, M.D., regularly sees the benefit of performing mitral valve repair early, before the appearance of gross symptoms such as orthopnea or cough becomes manifest.

"Deciding to make the repair early, based solely on diagnostic tests such as echocardiography, has been shown to be associated with far better outcomes," Merrick says.

Performing the surgery early helps preserve heart function by correcting regurgitation before it leads to heart dilation. And because tissue perfusion is still good, recovery from the procedure is quicker.

The push to make mitral valve repairs early is only one of several important changes that have swept the field in recent decades, Merrick says. One of the most important procedural differences between today and years past is that now the existing valve is often repaired, rather than replaced with an artificial or human valve. "Nearly all myxomatous mitral valves are repairable," Merrick says. Very few patients need a prosthetic valve anymore."

Part of the shift to repairing heart valves instead of replacing them has come from research showing the deleterious effect of cutting out the existing valve. "When you repair the valve, you save all those structures that attach the valve to the heart," Merrick says. "We've found that those attachments are important for maintaining the shape of the heart and its efficient function."

Studies have shown that cutting out those structures during valve replacement may not affect heart function immediately. But 10 years after surgery, the heart is demonstrably weaker.

Avoiding the insertion of synthetic materials in the heart severely reduces the risk of infection or thromboembolic complications, he adds. Quicker recovery from surgery is also promoted by the use of less invasive surgical techniques that have been developed in recent years.

When regurgitation has gone on long enough to dilate the heart, the stretched and weakened heart wall can contribute to atrial fibrillation or other heart rhythm problems. UCSF surgeons now commonly create a maze of scars in the myocardium that channel electrophysiological signals through the heart in a specific way, returning the heart to a sinus rhythm.

A specific strength of the UCSF cardiosurgery program is the widespread expertise in echocardiography, Merrick says. Those who staff the echocardiography labs are world-class experts in the technology, and have often been at the forefront of developing new techniques and equipment. The cardiac anesthesia group is also staffed with experts in echocardiography.

"Echocardiography is not only used before surgery to diagnose and plan the prodedure, but also during the procedure," Merrick says. "In a lot of cases, we don't even have to perform a cardiac catheterization" because the echocardiogram tells them all they need to know, he says.

The judicious use of the many advancements in mitral valve repair can produce outcomes that would have been highly unusual 20 year ago. For instance, one recent patient was an amateur athlete in his early 50s who came to UCSF with myxomatous mitral valve disease and no symptoms except for low-grade fatigue. "The valve was repaired, and he was competing again within two months, which was amazing," Merrick says.

To contact Dr. Scot Merrick, call (415) 353-1606.

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