Aetiology, prevalence, and prognosis.

Tricuspid regurgitation (TR) is a common yet often overlooked valvular disorder that carries a substantial impact on morbidity and mortality. It is increasingly recognized as a heterogeneous entity with different phenotypes identified (primary, atrial secondary, ventricular secondary, and cardiac implantable electronic device-related). Contemporary population studies and disease-specific registries reveal that secondary TR is highly prevalent in elderly patients, those with heart failure of any phenotype, and in candidates for transcatheter aortic or mitral interventions. Prognosis varies widely according to aetiology, with atrial secondary TR consistently associated with better survival than ventricular secondary TR. Across diverse settings, TR severity is an independent predictor of mortality, and several clinical scores, including the TRI-SCORE, Wang score, and TRIO score, have been developed to refine risk stratification. Recent staging models integrating ventricular function, renal status, and biomarkers suggest that intervention during an intermediate disease phase, before irreversible end-organ damage, may optimize outcomes. Together, these advances underscore the need for accurate phenotyping, structured prognostic assessment, and timely intervention to improve the care of patients with TR.