Impact of functional mitral regurgitation on long-term outcome in heart failure patients treated by cardiac resynchronization therapy

Abstract

Objective To investigate the association of baseline and follow-up changes of functional mitral regurgitation (MR) with long-term outcome in patients undergoing cardiac resynchronization therapy(CRT). Methods A total of 209 consecutive patients undergoing CRT were included in the study.Significant MR (SMR), defined as grading scale≥3, was quantified by color Doppler in all the patients at baseline and in 194 patients 6 months after CRT, respectively.The primary endpoint events included all-cause mortality, heart failure readmission and heart transplantation. Results The mean age of study patients cohort was (60.1±10.5) years old and 137 patients (65.6%) were male.One hundred and fifteen patients (55.0%) presented baseline SMR.After 6 months of CRT, 77 of the 194 patients (39.7%) became SMR.Over a mean follow-up of (23.2±16.8) months, there were 24 patients (11.5%) with all-cause deaths, 40 (19.1%) with heart failure readmissions and 4 (1.9%) with heart transplantations.In a multivariable model, the primary endpoint events were strongly associated with SMR after 6 months of CRT but not with baseline MR severity (P<0.05). Conclusion SMR after CRT rather than before CRT was strongly associated with less favorable long-term survival. Key words: Heart failure; Cardiac resynchronization therapy; Mitral regurgitation; Clinical outcome