The five phenotypes of tricuspid regurgitation: insight from cluster analysis of clinical and echocardiographic variables

Abstract Funding Acknowledgements Type of funding sources: None. Background Tricuspid regurgitation (TR) is a prevalent valvular lesion with three broad morphologic subtypes: primary due to intrinsic pathology of the valve or subvalvular apparatus; secondary due to pulmonary hypertension; and isolated TR associated with chronic atrial fibrillation. The complex pathophysiological, clinical and echocardiographic features between these subtypes require further investigation. Purpose We aimed to identify the different phenotypes of TR using cluster analysis, and determine differences (if present) in clinical outcomes associated with these phenotypes. Methods We included 13611 patients with ≥ moderate TR, either primary or secondary, in the final analyses. The demographic, clinical and echocardiographic data of these patients were evaluated using Ward’s minimum variance cluster analysis including a total of 38 variables. Survival analysis for all-cause mortality was performed using the Kaplan-Meier method, and groups were compared using the log-rank test. Results The mean age of patients was 72.5 ± 13.4 years, 7590 (56%) were females. The clustering identified 5 distinct phenotypes. Cluster 1 represented "low-risk TR" with lesser severity likely related to chronic atrial fibrillation. This cluster had less severe TR, normal sized right ventricle and fewer comorbidities. Clusters 2-5 represented "higher severity TR", "TR associated with lung disease", "TR associated with coronary artery disease and ischemic cardiomyopathy" and "TR associated with chronic kidney disease" respectively (Figure 1). Cluster 1 had the best overall survival, followed by clusters 2, 3 and 4, and lastly cluster 5, with the worst outcome (Figure 2). Conclusions Cluster analysis identifies 5 phenotypically distinct novel subgroups of TR with differences in all-cause mortality. This phenotype-based classification improves our understanding of interaction of different co-morbidities with this complex valve lesion and can inform clinical decision making. Abstract Figure. Cluster Dendrogram Abstract Figure. Kaplan-Meier survival curves