Heterotopic Caval Valve Implantation for Severe Tricuspid Regurgitation: A Systematic Review and Recommendations for Implantation and Futility

Background: Heterotopic transcatheter caval valve implantation (CAVI) has emerged as a palliative yet promising therapeutic strategy for treating severe tricuspid regurgitation (TR), which aims to reduce systemic venous congestion by implanting bioprosthetic valves in the venae cavae rather than in the native tricuspid annulus. However, despite encouraging procedural success, clinical improvement and survival remain highly variable. Methods: A systematic review of published registries and case series was performed, focusing on the outcomes, procedural success, mortality, and safety of CAVI. Data were extracted from multicenter registries and observational series describing the use of transcatheter stented bioprosthesis or bioprosthesis alone. Results: Across published cohorts and registries, procedural success rates ranged from 90% to 100%, with 30-day mortality ranging from 5% to 25%. The TRICUS EURO study, which included 35 patients across 12 European centers, demonstrated significant improvements in New York Heart Association (NYHA) functional class and Kansas City Cardiomyopathy Questionnaire (KCCQ) scores at 6 months, with minimal device-related complications and adverse events. The ongoing TRICAV-II pivotal trial (NCT06458907) and EuroTR registry (NCT06307262) are expected to provide larger real-world datasets. Smaller case series and individual reports, typically involving ≤10 patients, confirmed feasibility and symptomatic benefits, particularly reductions in peripheral edema and ascites. However, long-term outcome data remain limited. This study highlights right ventricle (RV) dysfunction, severe pulmonary hypertension, advanced end-organ failure, and clinical frailty as major determinants of unfavorable outcomes. Conclusions: Heterotopic CAVI represents a viable alternative for high-risk patients with severe TR, offering symptomatic improvement and reduced venous congestion when conventional surgery or orthotopic repair is not feasible. However, current evidence is derived primarily from non-randomized studies and limited registries. Ongoing prospective registries and pivotal trials are crucial for defining patient selection, procedural optimization, and long-term survival benefit. Early intervention and multidisciplinary patient selection appear crucial for avoiding futile procedures and identifying patients who may derive true symptomatic and prognostic benefit from CAVI.