Concomitant Tricuspid-Mitral Surgery Beneficial but With a Tradeoff

Patrice Wendling

November 13, 2021

Tricuspid valve repair at the time of mitral-valve surgery reduces tricuspid regurgitation progression but at the cost of more than a 5-fold increase in permanent pacemakers, a new Cardiothoracic Surgical Trials Network study shows.

The results were presented during the opening late-breaking science session at the virtual American Heart Association (AHA) Scientific Sessions 2021 and published simultaneously in the New England Journal of Medicine.

Tricuspid regurgitation (TR) is common among patients undergoing mitral valve surgery, and there's broad agreement to intervene when a patient has severe TR. There's uncertainty, however, about the management of moderate or less TR during mitral-valve surgery, which is reflected in current guidelines based on observational data, explained co-primary investigator James Gammie, MD, co-director and surgical director of the Johns Hopkins Heart and Vascular Institute, Baltimore, Maryland. As a result, rates of concomitant tricuspid-mitral surgery range from 5% to 75% at various centers.

To help fill the gap, Gammie and colleagues screened 5208 patients at 29 centers in the United States, Canada, and Germany undergoing surgery for degenerative mitral regurgitation and randomly assigned 401 patients (75% male) to mitral-valve surgery alone or with tricuspid annuloplasty.

Patients had either moderate TR (37%) or less than moderate TR with a dilated tricuspid annulus of at least 40 mm or at least 21 mm/m2 indexed for body surface area. Importantly, there was a uniform surgical approach using undersized (26 mm to 30 mm) rigid nonplanar annuloplasty rings to repair the tricuspid valve, he said.

The study's primary outcome of treatment failure at 2 years was defined as the composite of death, reoperation for TR, or progression of TR from baseline by 2 grades or severe TR.

The primary endpoint occurred in 10.2% of patients who underwent mitral-valve surgery alone and 3.9% who underwent concomitant tricuspid annuloplasty (relative risk, 0.37; 95% CI, 0.16 - 0.86; P = .02).

The endpoint was driven exclusively by less TR progression in the annuloplasty group, with no TR reoperations in either group, observed Gammie. At 2 years, just 0.6% of the annuloplasty group had severe TR compared with 5.6% of the surgery-alone group.

The rate of permanent pacemaker implantations, however, jumped from 2.5% with surgery alone to 14.1% with concomitant tricuspid annuloplasty (rate ratio, 5.75; 95% CI, 2.27 - 14.60). More than half of pacemakers were placed during the first 2 days after surgery.

There was no between-group difference in 2-year rates of all-cause mortality, major adverse cardiac and cerebrovascular events, readmission, quality of life, or functional status.

Less Than Moderate TR

In a post hoc analysis stratified by baseline TR severity, treatment failure was significantly less common with surgery plus tricuspid annuloplasty among patients with moderate TR (4.5% vs 18.1%) but not among those with less than moderate TR and tricuspid annular dilation (3.4% vs 6.1%).

Although the trial was not powered for the subgroup analysis, "these results call into question the idea that less than moderate TR with annular dilation should be an indication for tricuspid valve repair," Gammie told | Medscape Cardiology.

"I did not repair the tricuspid valve in the setting of less than moderate TR before the trial and my practice won't change, but it will be based on much better evidence," he added. "Of course, long-term data from our trial will be of great interest."

Discussant Joseph Woo, MD, chair of surgery at Stanford University in California, congratulated the authors on a "landmark trial" that addresses a highly relevant problem without a clear-cut indication.

In the 2020 AHA/American College of Cardiology (ACC) heart valve disease guideline, tricuspid valve surgery is a class I recommendation when there's severe TR (stages C and D) and left-sided valve surgery but a class 2a recommendation in patients with progressive TR (stage B) with an annular dilation of at least 40 mm.

"The interesting findings in this study include that moderate TR was only 37% of the enrolled patients and only 97% of the patients with degenerative MR received a mitral valve repair," Woo said. "This level of mitral valve repair is perhaps lower than what we might expect at these centers and lower, certainly, than what the AHA/ACC guidelines recommend for surgery on asymptomatic severe mitral regurgitation."

Panelist Roxanna Mehran, MD, Icahn School of Medicine at Mount Sinai in New York City, said, "What I was struck by is that we as clinicians believe that if you fix the mitral valve, maybe the tricuspid regurgitation will improve. And it seems like that is not what's happening, and I think that's a big takeaway."

Session co-moderator Joanna Chikwe, MD, head of cardiac surgery at Cedars-Sinai Medical Center, Los Angeles, California, said, "I think we can all agree that severe tricuspid regurgitation is a disaster for patients, and I think the fact the trial is designed for an additional 5 years' follow-up will hopefully give us some insights into the clinical impact of severe tricuspid regurgitation."

For now, "a back of the envelope calculation suggests that for every 20 patients with moderate tricuspid regurgitation that we repair the tricuspid valve in, we would prevent severe tricuspid valve regurgitation in 1 at the price of pacemakers in 2," she said.

Chikwe told | Medscape Cardiology that "transcatheter tricuspid repair is increasingly helping these patients, but if you could avoid it with a technique that doesn't cause incremental harm beyond, perhaps, the need for pacemakers, then this is helpful data that supports that approach."

The pacemaker burden is not negligible, she said, but also not surprising to surgeons. "If you look at national practice of mitral-tricuspid surgery, it's about 15% after that and it's simply because the conduction tissue is so close to the tricuspid annulus."

Pacemaker implantation rates, like those for concomitant tricuspid-mitral surgery, are also highly variable and in some single-center series only around 2%, Chikwe said. "So that suggests there are technical approaches that can minimize the pacemaker rate [like] being extremely careful to avoid suture placement around the area of the conduction tissues."

For some the tradeoff between reduced TR progression and the risk of a permanent pacemaker is worth it "but the fact that the trial didn't show a difference in survival, a difference in symptoms, or quality of life, might suggest that patients you anticipated were high risk for surgery or didn't have a longer projected survival aren't going to benefit from what is quite an aggressive surgical approach," Chikwe said.

In an accompanying editorial, Chikwe and Mario Gaudino, MD, Weill Cornell Medicine, New York, also point out that the "very dynamic nature of tricuspid regurgitation and wide variability in assessing tricuspid annular dilatation are additional compelling reasons to leave lesser regurgitation alone."

Julia Grapsa, MD, PhD, Kings College and tricuspid service lead at Guys and St. Thomas NHS, London, United Kingdom, also pointed to the need for longer-term follow-up but said increased use of imaging markers is also needed to help pinpoint TR progression in these patients. "For the moment, the results should remind imagers and clinicians to refer patients earlier."

"As a valvular heart physician, I see more and more patients coming in with significant severe tricuspid regurgitation post–mitral valve surgery and because of the time that's passed, there's dysfunction of the right heart, the left heart, and it's very hard to suggest an operation because they're at high risk," she said. "So we're discussing with these patients whether to do an intervention or medical management."

"Now with this study, and the pending longer follow-up by the authors, I'm optimistic that the class 2 recommendation will be class 1 in order to help our patients treat tricuspid regurgitation earlier than late," said Grapsa, who is also editor-in-chief of JACC: Case Reports.

The study was funded by the National Heart, Lung, and Blood Institute (NHLBI) and the German Center for Cardiovascular Research. Gammie reports a consultant/stockholder relationship with Edwards Lifesciences. Grapsa reports no conflicts of interest. Chikwe reports that as co-principal investigator/study director of NCT 05051033 (an NHLBI-sponsored Cardiothoracic Surgical Trials Network trial), she collaborates with several of the study authors.

N Engl J Med. Published online November 13, 2021. Abstract, Editorial

American Heart Association (AHA) Scientific Session 2021

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