LONDON – Heart failure patients who are candidates for cardiac resynchronization therapy in a routine clinical practice setting will likely not benefit from the addition of a defibrillator to a pacemaker, according to results of the CERTITUDE cohort study.
In CERTITUDE, most of the deaths in patients fitted with a cardiac resynchronization therapy–pacemaker (CRT-P) device were predominantly from causes other than sudden cardiac death (SCD), which is the main rationale for using a CRT-defibrillator (CRT-D) device, said lead investigator Jean-Yves Le Heuzey at the annual congress of the European Society of Cardiology.
“Our results should not be interpreted as a general lack of benefit from CRT-D vs. CRT-P or vice versa. Rather we demonstrate that given currently selected CRT-P patients in the French population, addition of a defibrillator may not significantly add to survival.” Therefore, patients who may be eligible for CRT should not “automatically” be considered as requiring a CRT-D, suggested Dr. Le Heuzey and his coinvestigators in an article that was published online at the time of the study’s presentation (Eur Heart J. 2015 Sep 1. doi: 10.1093/eurheartj/ehv455).
Current ESC guidelines on cardiac pacing and cardiac resynchronization therapy “leave flexibility for the physician” on the use of CRT-P and CRT-D” because there was no evidence of a superior effect of the latter over CRT alone, said Dr. Le Heuzey of René Descartes University in Paris at the meeting. A randomized, controlled trial would be the only way to determine this, but such a trial is unlikely to ever be conducted, he noted.
Despite the lack of evidence, however, CRT-D is widely used, more so in the United States than in Europe, Dr. Le Heuzey observed, where more than 90% of patients needing CRT would likely have a CRT-D rather than a CRT-P device implanted.
The aims of the CERTITUDE cohort study were to look at the extent to which CRT-P patients differ from CRT-D patients in a real-life setting, and to also see if there were patients in the CRT-P group that might have benefited from CRT-D.
The prospective, observational study involved 1,705 patients who were recruited at 41 centers throughout France over a 2-year period starting in January 2008. Of these, 31% were fitted with a CRT-P device and 69% with a CRT-D.
Results showed that patients who had a CRT-P versus a CRT-D implanted were significantly older, more often female, and more symptomatic. They were also significantly less likely to have coronary artery disease, more likely to have wider QRS intervals and to have atrial fibrillation, and more often had at least two comorbidities.
Analysis of the causes of death was performed at 2 years’ follow-up, which Dr. Le Heuzey conceded was a short period of time. At this point, 267 of 1,611 patients with complete follow-up data had died, giving an overall mortality rate of 8.4% per 100 patient-years for the entire cohort.
The crude mortality rate was found to be higher among CRT-P than CRT-D patients, at 13.1% versus 6.5% per 100 patient-years (relative risk, 2.01; 95% confidence interval, 1.56-2.58; P less than .0001). But when the cause of death was examined more closely, there was no significant difference in the number of SCDs between the groups (RR, 1.57; 95% CI, 0.71-3.46; P = .42) and no significant difference when a specific cause of death analysis was performed.
The main reasons for the almost doubled risk of death in the CRT-P group was an increase in non-SCD cardiovascular mortality, mainly progressive heart failure (RR, 0.27; 95% CI, 1.62-3.18) and other cardiovascular causes (RR, 4.4; 95% CI, 1.29-15.03), Dr. Le Heuzey and associates noted in the article.
“Overall, 95% of the excess mortality among CRT-P recipients was not related to SCD,” they wrote, noting that this “suggests that the presence of a back-up defibrillator would probably not have been beneficial in terms of improving survival for these patients.”
So where does this leave clinicians? Dr. Le Heuzey referred to Table 17 in the European guidelines (Eur Heart J. 2013;34:2281-2329) with guidance on factors favoring CRT-P or CRT-D. For instance, CRT-P might be favorable in a patient with advanced heart failure or one with severe renal insufficiency or on dialysis. Other major comorbidities or frailty or cachexia might veer a decision towards CRT without a defibrillator. On the other hand, factors favoring CRT-D include a life expectancy of more than 1 year; stable, moderate (New York Heart Association class II) disease; or low to moderate–risk ischemic heart disease, with a lack of comorbidities.