ORLANDO, Florida – CRT – or cardiac resynchronization therapy – works. It works really well.
It works so well that it can revitalize a sick heart, according to John Cleland, head of the department of cardiology at Castle Hill Hospital (Kingston-upon-Hull, UK).
Cleland, also chairman of the steering committee for the CARE-HF trial, reported findings of the CARE-HF study at a late-breaking clinical trials session of the American College of Cardiology (Bethesda, Maryland) annual meeting at the Orange County Convention Center, and he said that the study has demonstrated CRT's regenerative capability.
Sponsored by Medtronic (Minneapolis), the trial is a prospective, multi-center, randomized study of patients with New York Heart Association Class III or Class IV heart failure and showing greatly reduced ejection fraction. The patient pool in the trial had poor left ventricular function and received optimal heart failure drug therapy with ACE inhibitors and beta blockers.
The trial involved implantation of a Medtronic InSync or InSync III CRT device in 409 patients, with 404 patients in a control group. Investigators in the trial followed the 813 patients at 82 centers in 12 European countries for 29 months.
Offering testimonial to the impact of CRT, Cleland said that the resynchronization effect is, thus far, the only strategy he knows of that can not only slow the progress of heart failure – which he referred to as "cancer of the heart" – but can actually reverse that process.
He pointed to the cardiologist's goal of "prolonging life and reducing morbidity in this [heart failure] population" and that "a treatment that does both is the Nirvana of the cardiologist." He noted that after 18 months, "a large proportion [of study patients] have become asymptomatic."
While giving no detailed account of the mechanism of CRT, Cleland generally described it as improving "the teamwork" of the heart by increasing the efficiency of the right ventricle and reducing the volume of the left ventricle. This teamwork provided "a constellation of events," he said, to help the heart return to more normal functioning ability.
As one example, he cited the case of one female study patient, "on the cusp" of NYHA classes III and IV and an ejection fraction of 20%, who had been returned to the Class I/II region and with her ejection fraction improved to 50%.
"For many patients CRT alone [without drug therapy] is the preferred choice," he said, though adding that "obviously, we need more clinical trial evidence" for the technology.
Cleland noted that, unlike previous trials investigating CRT therapy, CARE-HF provided the patient pool size and duration to assess the impact of CRT alone on mortality, without a defibrillator component. He called the 29-month follow-up for the study the longest timeline for looking at this patient group.
"Other shorter trials have shown that CRT improved six-minute walk times and quality of life in these patients," Cleland said. But those "less powered" trials had shown no decreases in mortality. CARE-HF succeeded in demonstrating this, he said.
The study showed that CRT reduced the primary endpoint of the trial, death or hospitalization, for a major cardiovascular event, by 37%. It also showed significant results in the secondary endpoint, reducing all-cause mortality.
"Even if you put all of the previous trials of CRT together, they still don't give a clear message that there is a reduction in mortality," Cleland said. "CARE-HF does, and so it is showing that all the early promise of CRT was not just hype. It's for real."
"CRT should be offered routinely to patients with heart failure and cardiac dysynchrony if their symptoms persist despite optimal drug therapy," he said.
Not unexpectedly, Medtronic was enthusiastic about the trial results and the marketing prospects.
Steve Mahle, president of Medtronic Cardiac Rhythm Management, said that both the lifesaving benefits and the "advantages distinct" from those benefits "will increase the use of both CRT and CRT defibrillator systems in the treatment of many patients suffering from heart failure."
Mahle added: "More than 13 years ago, Medtronic set out to lead the way to improve treatment options and clinical outcomes for the millions of people worldwide who suffer from heart failure symptoms and have a poor prognosis, despite optimal drug therapy."
He noted Medtronic's support for more than 20 heart failure clinical studies following more than 9,000 patients worldwide to evaluate device-based therapies for heart failure.
Medtronic also is the sponsor of the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT), which has demonstrated the efficacy of defibrillators and led to increased reimbursement coverage of those devices by Medicare.