Atrial Functional Tricuspid Regurgitation as a Distinct Pathophysiological and Clinical Entity: No Idiopathic Tricuspid Regurgitation Anymore

Abstract

Functional tricuspid regurgitation (FTR) is a strong and independent predictor of patient morbidity and mortality if left untreated. The development of transcatheter procedures to either repair or replace the tricuspid valve (TV) has fueled the interest in the pathophysiology, severity assessment, and clinical consequences of FTR. FTR has been considered to be secondary to tricuspid annulus (TA) dilation and leaflet tethering, associated to right ventricular (RV) dilation and/or dysfunction (the “classical”, ventricular form of FTR, V-FTR) for a long time. Atrial FTR (A-FTR) has recently emerged as a distinct pathophysiological entity. A-FTR typically occurs in patients with persistent/permanent atrial fibrillation, in whom an imbalance between the TA and leaflet areas results in leaflets malcoaptation, associated with the dilation and loss of the sphincter-like function of the TA, due to right atrium enlargement and dysfunction. According to its distinct pathophysiology, A-FTR poses different needs of clinical management, and the various interventional treatment options will likely have different outcomes than in V-FTR patients. This review aims to provide an insight into the anatomy of the TV, and the distinct pathophysiology of A-FTR, which are key concepts to understanding the objectives of therapy, the choice of transcatheter TV interventions, and to properly use pre-, intra-, and post-procedural imaging.

Novel Computed Tomography Variables for Assessing Tricuspid Valve Morphology: Results from the TRIMA (Tricuspid Regurgitation IMAging) Study

“…All patients suffered from TR that was equal to or greater than severe. The mechanism was predominantly functional (atrial 68%, ventricular 14%), whereas four patients (18%) had a mixed etiology (lead-induced and functional) [ 21 , 22 ]. Baseline clinical characteristics of our study population are summarized in Table 1 .…”

Functional Tricuspid Regurgitation: Behind the Scenes of a Long-Time Neglected Disease

“…Atrial FTR (AFTR) was for long time called idiopathic FTR, so categorized due to the absence of any obvious cause; recently, its accurate study has allowed to revise the pathophysiological classification, awarding to the RA a primary role as its main determinant ( 17 , 21 – 23 ).…”

“…The advanced age and the presence of persistent/permanent atrial fibrillation (AF) are typically associated to the AFTR, reflecting as common denominator of the atrial contractile dysfunction ( 21 , 23 ). In particular, the onset of AF may modulate myocytes action potential and calcium release from the sarcoplasmic reticulum; regardless by AF, in the elderly, the frequent diastolic dysfunction may lead to an increase in atrial pressure and atrial stretch ( 25 , 26 ).…”

Reference ranges of tricuspid annulus geometry in healthy adults using a dedicated three-dimensional echocardiography software package

“…The dilation of the tricuspid annulus (TA) is one of the main determinants of the development and the severity of secondary tricuspid regurgitation (STR), particularly in patients with the atrial form of STR (1)(2)(3)(4). Moreover, the size of the TA is critical in determining the need for concomitant tricuspid valve (TV) interventions in patients undergoing left-sided valve surgery (5,6) and in the patient selection for transcatheter procedures to repair the regurgitant TV (7).…”