Transcatheter innovations in tricuspid regurgitation: FORMA device

Abstract

Transcatheter tricuspid valve interventions (TTVIs) have arisen in recent years as an alternative treatment of tricuspid regurgitation (TR) in high risk patients. TTVIs can be classified as annuloplasty devices, caval valve implantation (CAVI), tricuspid valve replacement and coaptation devices. The FORMA repair system (Edwards Lifesciences, Irvine, CA, USA) aims to improve the coaptation of tricuspid leaflets by occupying the regurgitant orifice with a balloon spacer, which reduces the regurgitant orifice area. After the first-in-human reported case back in 2015, data from 18 patients treated under compassionate clinical use conditions and from 29 patients under the US early feasibility (EFS) trial have been published. The two studies included very high-risk surgical patients (Euroscore II >8 in both cohorts). Implantation success was achieved in 16 (89%) and 27 (93%) of patients, respectively. In the US EFS trial, results at 30 days showed improvements in New York Heart Association (NYHA) functional class (NYHA class ≥ III in 28% vs 84% at baseline, p =0.0002), 6-minute walking test (increase by 21 m, p =0.012) and in the Kansas City Cardiomyopathy Questionnaire (increase by 29 points, p < 0001). In addition, the Core Lab evaluation at 30 days showed statistically significant reductions in TR severity grading in the 25 available patients. Regarding the compassionate cohort, 15 patients had available data at long-term follow-up (≥ 2 years). NYHA functional class ≥ III was reduced from 93% to 34% (p <0.001). However, two-thirds of the patients remained with significant TR at last available follow-up, and there were no significant changes in EROA (0.92 vs. 0.77 cm²; p = 0.516). In conclusion, this first experience with the FORMA device showed the feasibility of the procedure. Despite the magnitude of TR reduction was moderate at long-term, significant improvements in heart failure symptoms and quality of life were achieved.

Introduction

Transcatheter tricuspid valve interventions (TTVIs) have emerged in recent years as an alternative treatment of isolated tricuspid regurgitation (TR).¹ Patients with progressive TR have been traditionally managed medically, leading to progressive right ventricular dilation, dysfunction and end-stage chronic heart failure. As a result, late referral to surgical repair or replacement has been associated with the highest surgical risk among all valve procedures in contemporary practice, with operative mortality rates close to 10%.² The etiology of TR is functional >80% of cases³ and often occurs in patients with already surgically-treated left-side valvular disease, implying intrinsically a higher surgical risk. In this regard, several transcatheter systems have been developed in the last decade.¹ TTVIs can be classified according to their mode of action: annuloplasty devices, caval valve implantation (CAVI), tricuspid valve replacement and coaptation devices. Among the latter, the FORMA repair system (Edwards Lifesciences, Irvine, CA, USA) aims to improve the coaptation of tricuspid leaflets by occupying the regurgitant orifice with a balloon spacer, which reduces the regurgitant orifice area. The present document focuses on the FORMA device, describing its design characteristics, main procedural steps and reported outcomes.