Surgery Does Not Improve Survival in Patients With Isolated Severe Tricuspid Regurgitation

Abstract

Background: Patients with isolated tricuspid regurgitation (TR) in the absence of left-sided valvular dysfunction are often managed nonoperatively.

Objectives: The purpose of this study was to assess the impact of surgery for isolated TR, comparing survival for isolated severe TR patients who underwent surgery with those who did not.

Methods: A longitudinal echocardiography database was used to perform a retrospective analysis of 3,276 adult patients with isolated severe TR from November 2001 to March 2016. All-cause mortality for patients who underwent surgery versus those who did not was analyzed in the entire cohort and in a propensity-matched sample. To assess the possibility of immortal time bias, the analysis was performed considering time from diagnosis to surgery as a time-dependent covariate.

Results: Of 3,276 patients with isolated severe TR, 171 (5%) underwent tricuspid valve surgery, including 143 (84%) repairs and 28 (16%) replacements. The remaining 3,105 (95%) patients were medically managed. When considering surgery as a time-dependent covariate in a propensity-matched sample, there was no difference in overall survival between patients who received medical versus surgical therapy (hazard ratio: 1.34; 95% confidence interval: 0.78 to 2.30; p = 0.288). In the subgroup that underwent surgery, there was no difference in survival between tricuspid repair versus replacement (hazard ratio: 1.53; 95% confidence interval: 0.74 to 3.17; p = 0.254).

Conclusions: In patients with isolated severe TR, surgery is not associated with improved long-term survival compared to medical management alone after accounting for immortal time bias.

Keywords: immortal time bias; isolated severe tricuspid regurgitation; survival analysis.

Central Illustration:. Surgery Versus Medical Therapy for Severe Tricuspid Regurgitation.

Cumulative survival in propensity-matched sample of patients with isolated severe tricuspid regurgitation adjusting for time from diagnosis to surgery as a time-dependent covariate. * Curves generated using an extended Kaplan-Meier estimator which allows the cohorts to vary with time depending on the covariate pattern (surgery vs no surgery.) The time of origin is the first echocardiographic diagnosis of severe TR for all patients, however, each curve does not correspond to a fixed cohort of patients, as surgical patients are allowed to contribute risk to the medical group prior to the time of surgery.

Figure 1:. Graphical Depiction of Immortal Time Bias.

Immortal time bias is the span of time in observational studies when the outcome could not have occurred due to how the exposure was defined. In this case, this was the time from diagnosis of severe TR to surgery. The subject necessarily had to survive until surgery to be classified as having surgery in this analysis.

Figure 2:. Cumulative Survival Adjusting for Time from Diagnosis to Surgery.

Overall survival (A) entire cohort and (B) propensity-matched sample of patients adjusting for time from diagnosis of severe TR to surgery as a time-dependent covariate. Hazard ratio (HR) is for surgery relative to medical management. * Curves generated using an extended Kaplan-Meier estimator which allows the cohorts to vary with time depending on the covariate pattern (surgery vs no surgery.) The time of origin is the first echocardiographic diagnosis of severe TR for all patients, however, each curve does not correspond to a fixed cohort of patients, as surgical patients are allowed to contribute risk to the medical group prior to the time of surgery.

Figure 3:. Cumulative Survival of Surgical Subgroup.

Overall survival for patients who received surgery comparing tricuspid valve repair versus replacement.