Mitral Regurgitation Surgical Repair Rates, Durability Continue to Improve

SAN FRANCISCO, CALIF.—As surgical repair of mitral regurgitation has become more common over the last three decades, operative mortality rates and durability of success have both improved dramatically. However, there is still room for improvement, especially with regard to treatment rates.

“Over the last decade, the relative contribution of valve operations to cardiac surgical practice has substantially increased,” James S. Gammie, MD, of University of Maryland Heart Center in Baltimore, said during a scientific symposia session.

Based on data from the Society of Thoracic Surgeons National Database, Gammie said that “currently over a third of [cardiac] operations in North America have a valve component.” The database — which is thought to cover more than 90% of hospitals that perform cardiac procedures in the United States and Canada — accrues over 100,000 heart valve operations each year, about 40% of which are mitral operations.

Gammie discussed one study using the STS database that looked at 58,370 isolated primary mitral valve operations between 2000 and 2007. Over that period, the rate of mitral regurgitation repair increased from 51% to 69% (P<.0001). There was also a substantial change in the type of mitral valve replacement used: in 2000, mechanical valves accounted for 68%, and in 2007 bioprosthetic valves were used 63% of the time.

Less invasive procedures

There is also a continuing trend toward the use of less invasive surgery for mitral regurgitation. In a 2010 study, 15% of 28,143 isolated primary mitral valve operations performed between 2004 and 2008 were considered less invasive. Of those less invasive procedures, 35% were robotic surgeries. The less invasive operations rose from 11.9% of the total operations performed in 2004 to 20.1% in 2008. Notably, among 709 centers in 2008, only 26% performed at least one less-invasive operation. Of those centers, most perform a very low number of less invasive surgeries; the median was 3 such cases per year.

According to Maurice E. Sarano, MD, of the Mayo Clinic, in Rochcester, Minn., these surgical trends and increasing treatment rates have been accompanied by a drastic reduction in operative mortality, especially among elderly patients, since the early 1980s. Patients undergoing mitral regurgitation surgery who were older than 75 years of age had an operative mortality rate of close to 30% in the early 1980s, but by the mid-1990s it had dropped to about 5%, he said.

Still, there are opportunities for improvement; Sarano noted that recurrent mitral regurgitation is still an issue, with rates most likely at around 10% to 15% within 10 years of surgery. One way to reduce recurrence rates, he added, would be to focus on eliminating any residual mitral regurgitation after surgery. “A little bit of mitral regurgitation is unacceptable,” Sarano said. “We should aim for a perfect repair, if at all possible.”

The durability of the specific treatment is important, Sarano added. “There is a better durability of posterior leaflet prolapse than with putting in a mechanical valve currently,” he said. “The technical issues of surgery have improved to the point that repair has become the paradigm of durability.”

European trends

Alec Vahanian, MD, of Hôpital Bichat in Paris, reported similar trends in Europe with regard to mitral regurgitation treatments. He noted the rapid adoption of percutaneous repair using the MitraClip system (Abbott Vascular); in one recent study, 32 patients with NYHA class III or IV and left ventricular ejection fraction of 25% or less treated with MitraClip saw marked improvements. At 6 months, 23 of them had improved to NYHA class I or II.

The most important issue to improve on with mitral regurgitation, Vahanian said, is that of non-treatment; many reasons can play a role in decisions not to treat, from advanced age to comorbidities. The success of modern surgical techniques, though, should drive more people to treatment than in the past.

“We have to do a better job [of referring to treatment when warranted],” Vahanian said. “We should not be indifferent to whether or not surgery is performed.”