Atrial functional tricuspid regurgitation (afTR) is a predictor for tricuspid regurgitation (TR) persistence and aggravation in transcatheter aortic valve replacement (TAVR) patients, a study suggests. The investigation also concludes that TR in the presence of aortic stenosis (AS) is not always caused by left-sided heart disease but, rather, can occur as an independent entity. Writing in the Jan. 8 issue of JACC Cardiovascular Interventions, the paper’s authors also suggested that TR persistence after TAVR is associated with a significantly higher 3-year all-cause mortality compared with patients with TR improvement. “This result is in line with previous studies, describing an association between persistent or worsening TR and increased all-cause mortality after TAVR or surgical aortic valve replacement,” the research team said. “However, despite a higher rate of TR persistence and TR aggravation in patients with afTR, no difference in 3-year all-cause mortality was observed when patients were stratified for afTR and non-afTR.” Primary findings The investigative team’s results, which were published Monday online, identified 420 patients with concomitant at least moderate TR out of 3,474 TAVR patients. A total of 363 patients were included in the study, with 178 patients stratified in the afTR and 185 in the non-afTR group. This stratification was based on a receiver-operating characteristic curve cutoff of 1.132 of the right atrial/right ventricular area ratio. The researchers revealed that TR improvement of at least one grade after TAVR was observed in significantly fewer patients with afTR compared with non-afTR (31.1% vs 60.6%; P<0.001). A multivariate regression analysis confirmed afTR as an independent predictor for TR persistence (adjusted odds ratio: 2.80; 95% confidence interval [CI]:1.66-4.76; P<0.001). Additionally, afTR is associated with aggravation of TR after TAVR (17.0% vs 6.8%; P=0.013). Three-year all-cause mortality was also significantly lower in patients whose TR improved than in those with TR persistence (corresponding hazard ratio: 0.50; 95% CI: 0.33-0.74;P<0.001). Left-sided valvular disease not underlying cause? “Because afTR is less likely to improve after TAVR in patients with severe AS, it is probable that left-sided valvular disease may not be the underlying cause, but rather may be an independent entity in these patients,” said the research team, led by Kornelia Löw, MD, from the Medizinische Klinik und Poliklinik I, LMU-Klinikum in Munich. “Particularly, in patients with afTR and left-sided valvular disease, the probability of TR being an independent disease is high, as expressed by the lack of improvement after TAVR.” Antonio Mangieri, MD, and Mauro Gitto, MD, both from the IRCCS Humanitas Research Hospital in Rozzano-Milan, highlighted the study’s afTR definition, which was based on the ratio of right atrial to right ventricular area. In their editorial comment of the investigation, the experts suggested this definition led to the inclusion of mixed fTR etiologies, in which the “atrial component” variably contributes to the pathophysiology of tricuspid valve disease. When placed in the context of recent literature, the commentators acknowledged that the study’s results show two- to fourfold higher afTR prevalence and highlight a huge unmet clinical need. Reclassification “On the basis of the inclusion criteria of previous registries, a consistent proportion of patients with afTR in the study by Löw et al, who had severe aortic stenosis, at least moderate mitral regurgitation in one-half of cases, and a mean systolic pulmonary artery pressure of almost 50 mm Hg, would have been reclassified as having ventricular fTR (vfTR),” the experts wrote. “This justifies the worse prognosis of the newly defined afTR category, the long-term mortality of which was comparable with that of patients with vfTR, and the recently described worsening of TR grade in a significant proportion of patients with fTR after percutaneous correction of left-sided valvular disease.” The commentators concluded that distinguishing between afTR and vfTR might not be straightforward, as both conditions tend to overlap in the advanced stage of their natural course. Study methodology The research team analyzed patients undergoing TAVR for severe AS from January 2013 to December 2020 and concomitant at least moderate TR at baseline. Out of 3,474 patients treated with TAVR, at least moderate TR at baseline was found in 420 patients. Of those, 363 (46.6% male, median age 83.5 years, [interquartile range: 79.0-82.3]) were eligible for this study. A total of 178 patients were stratified in the afTR group, with 185 patients stratified in the non-afTR group based on a receiver operating characteristic curve cutoff of 1.132. afTR was defined as enlargement of the right atrium in relation to the right ventricle. TR development after TAVR and 3-year all-cause mortality were evaluated. The primary outcome of the study was the improvement of TR of at least one grade after TAVR in patients with afTR compared with nonafTR. Sources: Löw K, Steffen J, Lux M, et al. Atrial Functional Tricuspid Regurgitation in Patients Undergoing Transcatheter Aortic Valve Replacement. JACC Cardiovasc Interv. 2023;17:76 –87. Mangieri A, Gitto M. Navigating the Heterogeneous Landscape of Atrial Functional Tricuspid Regurgitation. JACC Cardiovasc Interv. 2023;17:88–90. Image Credit: korawig – stock.adobe.com