Which type of valve should we use in tricuspid position? Long-term comparison between mechanical and biological valves.

Background: Nowadays, tricuspid valve replacement (TVR) is much less common than aortic or mitral valve replacement, since repair is almost always preferable. Prosthetic tricuspid valves are associated with high mortality and morbidity, mostly due to thrombotic or hemorrhagic events. Nevertheless, there is lack of evidence of which is the optimal type of valve (biological versus mechanical) in tricuspid position.
Methods: We analyzed all the patients who underwent TVR in our Institution, from 2005 to 2015. Patient baseline characteristics were recorded (such as functional class, previous cardiac surgery, right ventricular dysfunction or pulmonary hypertension), and a clinical long-term follow-up was conducted. We compared the outcomes between mechanical and biological prostheses: in-hospital mortality, long-term mortality, need for reintervention and adverse events (such as stroke or valve thrombosis).
Results: During the study period 120 tricuspid prosthetic valves were implanted in 111 patients. 81 of them (67.5%) were bioprostheses, and 39 (32.5%) mechanical valves. 73 patients (60.8%) had undergone a previous cardiac surgery (28.4% had previous tricuspid surgery). Most of the patients (87.1%) were in high functional class (grade III-IV of the NYHA classification), and 85% had moderate to severe pulmonary hypertension. Mean logistic EuroSCORE I was 14.80%. Only 37 cases were isolated TVR (30.6%), as most of the cases were TVR concomitant to mitral valve replacement. In-hospital mortality was 21.7%, and during the follow-up (mean follow-up of 7 years) reached 37.5%. Three mechanical tricuspid valves (7.7%) had to be replaced due to thrombosis, while 7 biological valves (8.6%) had to be replaced due to valve deterioration. The incidence of stroke was 7.5%.
Conclusions: Tricuspid valve replacement is an infrequent procedure with a high incidence of perioperative morbidity and mortality. Biological or mechanical valves have similar mortality, and a reasonably low incidence of need for reintervention due to thrombosis or valve deterioration.