Surgery for Isolated Severe Regurgitation Does Not Improve Survival
Key findings
- In a retrospective study of 3,276 patients with isolated severe tricuspid regurgitation, initial analysis showed significantly better long-term survival in those who underwent surgery than in those who received medical therapy alone
- However, in a propensity-matched cohort of 124 patients, there was no survival difference between groups after accounting for immortal time bias
- In the surgical group, there was no survival difference between patients who had tricuspid valve repair versus replacement
- Forthcoming randomized trials of novel percutaneous therapies for tricuspid regurgitation should focus on the optimal timing of intervention
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Isolated tricuspid regurgitation (TR), meaning without left-sided heart disease, pulmonary hypertension or congenital abnormalities, was not recognized until 2004. It is an increasingly common diagnosis, but the role of surgery in these cases is unclear. In the only previous study that compared medical versus surgical treatment, long-term survival was not significantly longer after surgery.
Andrea L. Axtell, MD, clinical surgical fellow, Jason Wasfy, MD, MPhil, medical director, Massachusetts General Hospital Physicians Organization, and Thoralf M. Sundt, MD, chief of Cardiac Surgery at Massachusetts General Hospital Corrigan Minehan Heart Center, and colleagues recently performed a similar retrospective study in patients with isolated severe TR. They found that surgery was not associated with improved survival compared with medical therapy alone, according to their report in the Journal of the American College of Cardiology. This work was supported by the National Institutes of Health through Harvard Catalyst, the American Heart Association, and a SPARK grant from the Corrigan Minehan Heart Center.
The Study Cohort
The researchers analyzed 3,276 patients who underwent echocardiography at Mass General between November 2001 and March 2016 and were diagnosed with isolated severe TR. The type of intervention was chosen at the discretion of the patient's cardiologist and cardiac surgeon.
Only 171 patients (5%) underwent tricuspid valve surgery and the rest were medically managed. The median follow-up time was 2.6 years.
Survival in the Entire Cohort
In an unadjusted comparison of the entire cohort, patients who underwent surgery had an apparent survival benefit (HR, 0.62; 95% CI, 0.49–0.78; P < .001).
Survival in a Propensity-Matched Cohort
The primary outcome measure was survival in a propensity-matched cohort. In this analysis, time from diagnosis of severe TR to surgery was considered a covariate.
Specifically, the researchers matched each of 62 patients who underwent medical therapy with a patient who underwent surgery. Each pair was similar in age, gender, certain comorbidities and left ventricular ejection fraction.
In this analysis, there was no significant difference in overall survival between the medical and surgical treatment groups (HR, 1.34; 95% CI, 0.78–2.30; P = .29).
Immortal Time Bias
The researchers emphasize that the primary analysis accounted for immortal time bias. Accounting for bias related to immortal time is a critical component of many types of comparative effectiveness research with observational data. For example, in the current study, patients waited up to eight years for surgery. If immortal time is not considered, patients who are first medically managed and then ultimately receive surgery would inaccurately have all of their survival attributed to surgery.
Rethinking the Timing of Intervention
Randomized, controlled trials are underway to evaluate novel catheter-based percutaneous techniques for tricuspid valve repair and replacement, which may prove to be associated with lower procedural risk. The current study suggests, though, that these trials may not demonstrate a survival benefit over medical therapy.
Still, changes in the approach to surgery provide an important opportunity. These trials should attempt to redefine the appropriate timing of intervention in patients with TR, with the aims of improving overall survival and quality of life.
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