MUNICH – Cardiac resynchronization in patients with mild heart failure produced durable benefits during an average 4.5 years of follow-up, with evidence for ongoing cardiac remodeling and reduced disease progression in a series of 419 patients.
"The benefits of CRT [cardiac-resynchronization therapy] persisted, indicating that CRT attenuates disease progression in mildly symptomatic heart failure patients with wide QRS," Dr. Cecilia Linde said at the annual congress of the European Society of Cardiology.
"The results clearly show that the reverse remodeling produced by CRT was sustained over 5 years, and that’s good news for the treatment of patients with heart failure and an indication for cardiac resynchronization," commented Dr. Gerhard Hindricks, professor and director of the department of electrophysiology at the Leipzig (Germany) University Heart Center.
The findings "confirm the results from RAFT [Resynchronization-Defibrillation for Ambulatory Heart Failure Trial (N. Engl. J. Med. 2010;363:2385-95)] with respect to the long-term outcome of CRT in patients with NYHA [New York Heart Association] class II heart failure for survival and heart failure hospitalization, and provide novel, long-term information on reverse remodeling" from CRT in these patients, commented Dr. Angelo Auricchio, director of the cardiac electrophysiology program at the Ticino Cardiac Center in Lugano, Switzerland.
The data analyzed by Dr. Linde and her associates came from 419 patients originally enrolled in the "CRT on" arm of the REVERSE (Resynchronization Reverses Remodeling in Systolic Left Ventricular Dysfunction) trial, which enrolled patients with NYHA class I or II heart failure and a QRS duration or at least 120 msec. The primary end point of the study was the composite of death or heart failure hospitalization during the first 12 months of active CRT use compared with patients who received a CRT device that had not been turned on (J. Am. Coll. Cardiol. 2008;52:1834-43). The new analysis reported by Dr. Linde focused on 419 patients initially randomized to the CRT-on arm who continued on active CRT use for up to 5 years, with an average follow-up of 4.5 years. The researchers collected complete follow-up data for 95% of these patients through 3 years, for 89% through 4 years, and for 85% through 5 years.
At baseline, the patients had an average age of 63 years; 78% were men, and 82% had NYHA class I heart failure, with a average left ventricular ejection fraction of 27%. Their average QRS duration at entry was 153 msec, and 56% of the patients had an ischemic etiology for their heart failure.
Annual follow-up findings showed a consistent, linear rate of death and first heart failure hospitalization throughout follow-up, with an annual mortality rate of 3% and an annual rate of death or first heart-failure hospitalization of 6%, said Dr. Linde, a cardiologist at the Karolinska Institute in Stockholm.
The results also showed a stable pattern of left-ventricular reverse remodeling following the first year on CRT. After 12 months, patients had an average cut in the left ventricular end diastolic volume index of 19 mL/m2; 25 mL/m2 after 24 months; and 23 mL/m2 after 5 years. The average drop in left ventricular end systolic volume index was 18 mL/m2 after 12 months; 24 mL/m2 after 24 months; and 23 mL/m2 at 5 years. Other measures of heart failure severity – the 6-minute walk, the Minnesota Living With Heart Failure score, and the Kansas City Cardiomyopathy Questionnaire score all improved significantly during the first 12 months on CRT therapy, and then held fairly steady during the subsequent 4 years. At 12 months, about 43% of patients had NYHA class I disease, about 53% had class II disease, and the rest had class III disease (which compared with rates of 18% with class I and 82% with class II at baseline). After 5 years, roughly 34% of patients had NYHA class I heart failure, about 56% had class II, about 9% had class III, and about 1% had class IV disease.
The majority of left-ventricular lead complications – the main adverse event of treatment – occurred during the first 12 months, with a cumulative incidence of 9% after 1 year. At 5 years, 13% of patients had experienced a lead complication.
The REVERSE trial was sponsored by Medtronic. Dr. Linde said that she has been a consultant to Medtronic and St. Jude and received research grants from Medtronic. Dr. Hindricks said that he received honoraria from and served on advisory boards for Biosense, Stereotaxis, St. Jude, and Biotronik. Dr. Auricchio said that he was a speaker for, consultant to, and received honoraria from Medtronic, St. Jude, and several other device and drug companies.