Prevalence, Incidence, and Outcomes of Diastolic Dysfunction in Isolated Tricuspid Regurgitation: Perhaps Not Really “Isolated”?

Background: In the absence of left-sided cardiac/pulmonary disease, functional tricuspid regurgitation (FTR) is referred to as isolated or idiopathic. Relationships between left ventricular diastolic dysfunction (DD) and FTR remain unknown. Objectives: The purpose of this study was to investigate the prevalence, incidence, and outcome of DD in patients with idiopathic FTR. Methods: Adults without structural heart disease were identified. Severe DD was defined by ≥3 of 4 abnormal DD parameters (medial e’, medial E/e’, TR velocity, left atrial volume index) and ≥ moderate DD by ≥2. Propensity-score matching was performed (3:1) between each less-than-severe TR group and severe TR based on age, sex, body mass index, and comorbidities. Results: Among 30,428 patients, FTR was absent in 73%, mild in 22%, moderate in 4%, and severe in 0.4%. In the propensity-matched sample, severe DD was present in 2%, 6%, 9%, and 13% patients, and ≥ moderate DD in 11%, 18%, 28%, and 48%, respectively (P < 0.001). The probability of heart failure with preserved ejection fraction using the H₂FPEF score increased with increasing FTR (median 29.7%, 45.5%, 61.4%, and 88.7%, respectively), as did the prevalence of impaired left atrial strain <24% (35%, 48%, and 69% in mild, moderate, and severe TR). Incident severe and ≥ moderate DD developed more frequently with increasing FTR (HR: 8.45 [95% CI: 2.60-27.50] and HR: 2.82 [95% CI: 1.40-5.69], respectively for ≥ moderate vs no FTR) over a median of 3.0 years. Findings were confirmed in patients without lung disease or right ventricular enlargement. Over a median of 5.0 years, patients with ≥ moderate FTR and DD had the greatest risk of worse outcomes (multivariable P < 0.001). The association between TR and adverse outcomes was significantly diminished in the absence of DD. Conclusions: Diastolic dysfunction, increased heart failure with preserved ejection fraction probability, and impaired left atrial strain are commonly present in patients with idiopathic FTR, suggesting that the latter may not be truly isolated. Patients with FTR without DD or heart failure are at increased risk of incident DD. Patients with FTR and DD display worse outcomes.