Young, Katie

Introduction: Severe tricuspid regurgitation (TR) is associated with considerable morbidity/mortality in an elderly population with multiple comorbidities. There is interest in transcatheter interventions to manage severe TR in this population. Understanding right heart (RH) anatomy has implications for patient/device selection for transcatheter intervention. Hypothesis: We analyzed RH anatomy by CT of patients referred for TR therapy to determine transcatheter tricuspid intervention device sizing needs. Methods: Retrospective Mayo Clinic study of 29 patients considered for intervention of severe TR from 3/1/2016-12/15/2020; echocardiogram and CT angiogram obtained in all patients. Results: Mean age was 83±8 (83% female), 100% had atrial fibrillation, and 62% had chronic kidney disease ≥3a. 97% were symptomatic, 93% were prescribed loop diuretics, and 24% had device leads. Mean tricuspid annular plane systolic excursion 16.8±4.5 mm, effective regurgitant orifice area (EROA) 81±33 mm 2 , and cardiac index 2.6±0.6 L/min/m 2 . 41% had at least moderate right ventricular (RV) dysfunction with a mean RV systolic pressure of 46±16 mmHg. Patients receiving intervention had significantly larger EROA (101±33 v. 63±22 mm 2 , P=0.033), shorter tricuspid leaflet tenting length (6.5±3.0 v. 8.9±2.7 mm, P=0.042), and smaller annuloplasty diagnostic perimeter during diastole (120.1±16.6 v. 131.1±7.4 mm, P=0.041). Intervention patients tended to have better right ventricular function, smaller RV and IVC size, and more severe symptoms. Max tricuspid annulus diameter in systole and diastole was 51±5 and 53±7 mm, respectively. Conclusions: Severe TR patients referred for transcatheter intervention present with severe RH enlargement with a large proportion having tricuspid annulus dimensions outside the range for current devices available in clinical trials. These data have implications for device development/selection and procedural feasibility.