Surgery doesn’t improve survival in patients with isolated severe tricuspid regurgitation (TR), researchers have found.
Andrea L. Axtell, MD, MPH, was lead author on a recent study, which drew from a longitudinal echocardiography database to retrospectively analyze more than 3,000 adults with isolated severe TR. The American College of Cardiology and American Heart Association’s most up-to-date guidelines recommend tricuspid valve surgery for patients with severe, symptomatic TR—especially if they also present with annular dilation and right heart failure—but only a handful of candidates go through with the surgery.
“Most patients with significant TR have concomitant left-sided heart disease and heart failure,” Axtell, of Massachusetts General Hospital in Boston, and co-authors wrote in the Journal of the American College of Cardiology. “Historically, these patients often were treated with medical therapy targeting the underlying disease processes and diuretic agents to address volume overload.”
Axtell et al. said it’s unclear whether those therapies alter patients’ prognoses or symptoms in any significant way, especially if they have primary valve disease. But the ACC/AHA’s recommendation of surgery is tenuous, too—it’s based on a Class C level of evidence and is only recommended in patients undergoing concomitant left-sided valve surgery.
Because of the paucity of data on the subject, just 500 people in the U.S. undergo isolated TR surgery each year.
Axtell and her team reviewed data from 3,276 patients who were diagnosed with isolated, severe TR between November 2001 and March 2016. Of those thousands of patients, just 171, or 5%, underwent tricuspid valve surgery.
Surgeries included 143 valve repairs and 28 valve replacements; the remaining 95% of patients were managed medically. The authors found that, when considering surgery as a time-dependent covariate in a propensity-matched sample, there was no difference in overall survival between patients who underwent surgery and those who didn’t (HR 1.34). In the surgery cohort, there wasn’t any difference in survival between surgery types (HR 1.53).
“Whereas an analysis of the entire cohort adjusted for time from diagnosis to tricuspid valve surgery suggested that surgery was associated with a significant long-term survival benefit compared with medical therapy, the same analysis applied to the propensity-matched sample showed no difference in outcome between the groups,” Patrick T. O’Gara, MD, and colleagues wrote in an editorial comment. “Five-year survival rates for both groups in the propensity analysis approximated 50%.”
O’Gara, of Brigham and Women’s Hospital, et al. said that despite the “many techniques” Axtell and her co-authors used to reduce their limitations, observational studies are inherently limited by potential selection bias and other confounders.
“Axtell et al. demonstrate how non-rigorous application of observational data can be misleading and potentially detrimental,” O’Gara and colleagues wrote. “For example, trial design and sample size calculations that rely on estimated effect sizes gleaned from observational studies of unblinded and non-standardized interventions conducted over long time horizons can easily miss their targets.”
The editorialists said there are a number of challenges to conducting randomized controlled studies in the surgical space, but a handful of trials are presently attempting to do so. The experience researchers gained from one particular assessment of edge-to-edge clip repair for mitral regurgitation patients, they noted, just emphasizes that fact that consistently applied, rigorous medical therapy works and is an appropriate standard against which to judge the effectiveness of surgical interventions.