Minimally Invasive Mitral Valve Surgery Gives Good Outcomes Without Increasing Costs

Minimally invasive surgical approaches for repairing or replacing the mitral valve (mini-MVR) provide short-term outcomes similar to those seen with conventional sternotomy without increasing costs, a multicenter study shows.

The fact that costs were not higher was unexpected, senior author Gorav Ailawadi, MD (University of Virginia, Charlottesville, VA), told TCTMD. But because mini-MVR results in shorter lengths of stay in the ICU and hospital plus a reduced need for blood transfusion, these factors probably offset the upfront costs of using minimally invasive approaches, he explained.

The findings “should provide reassurance to surgeons considering adding this technique to their armamentarium,” Ailawadi, lead author Emily Downs, MD (University of Virginia), and colleagues say in their paper published online March 31, 2016, ahead of print in the Annals of Thoracic Surgery.

“Mini-MVR should be the preferred approach for isolated mitral surgical procedures in appropriately selected patients at centers demonstrating excellence in minimally invasive outcomes,” they write. Ailawadi noted that it probably already is the first-line approach at centers performing a high volume of mitral valve operations.

Mini-MVR started being performed in the early to mid-2000s, Ailawadi said, and a prior study showed that it accounted for about 20% of mitral valve procedures by 2008. But despite positive results from single-center studies, adoption of minimally invasive techniques has been slow. Issues potentially keeping surgeons from embracing mini-MVR include the learning curve, the need for specialized equipment, uncertainty about whether outcomes are truly similar to those achieved with conventional surgery, and concerns about stroke and higher costs.

In recent years, however, there has been an uptick in interest in minimally invasive approaches, driven by the success of TAVR for aortic valve disease and the development of percutaneous techniques for mitral valve disease, Ailawadi said. “As these new technologies have come out and they’re less invasive, I think surgeons have had to reevaluate how [they could] make this easier for the patient to get through.”

To evaluate costs and outcomes with mini-MVR across multiple centers, the researchers looked at the Virginia Cardiac Surgery Quality Initiative database, which has been certified by the Society of Thoracic Surgeons. The database includes information from a consortium of 18 hospitals and 14 cardiac surgery practices. The current study included 1,304 patients undergoing mitral valve surgery with or without A-fib ablation between January 2011 and June 2014, after excluding patients undergoing CABG or other concomitant procedures. Overall, 32.6% of patients underwent mini-MVR.

The investigators used propensity matching to account for baseline differences, yielding 355 pairs of patients undergoing mini-MVR or surgery with a conventional sternotomy.

In matched patients, mini-MVR was associated with longer operative times, including median cross-clamp time (108 vs 85 minutes) and median cardiopulmonary bypass time (137 vs 112 minutes; P < 0.001 for both). Patients undergoing mini-MVR also were more likely to receive concomitant A-fib ablation, repair instead of replacement, and femoral artery cannulation.

Outcomes, however, were similar regardless of surgical approach, with an operative mortality rate of 1.1% and a postoperative stroke rate of 0.9% in both groups.

“To our knowledge, this is the first multi-institutional study to document similar stroke rates with a mini-MVR approach in the modern era after the concerns raised by previous reports from the [Society of Thoracic Surgeons. This] is likely the result of careful patient selection and screening,” the authors write.

Although clinical outcomes did not differ, mini-MVR was associated with shorter median stays in the ICU (24 vs 29.3 hours; P = 0.006) and hospital (4 vs 5 days; P < 0.001) and a lower likelihood of requiring postoperative blood products (11.6% vs 27.9%; P < 0.001).

Median hospital costs were $34,857 with mini-MVR and $38,133 with conventional sternotomy (P = 0.17).

Ailawadi said mini-MVR should be the first-line approach for most patients undergoing mitral valve surgery, but noted that it may not be appropriate for certain subsets. Surgeons should be more cautious about using a minimally invasive approach in patients with a lot of calcification around the valves, poor RV function, prior right chest surgery, morbid obesity, or a need for concomitant CABG, he said.

• Downs EA, Johnston LE, LaPar DJ, et al. Minimally invasive mitral valve surgery provides excellent outcomes without increased cost: a multi-institutional analysis. Ann Thorac Surg. 2016;Epub ahead of print.

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