CRT begets CRT-D: is one better than the other?

Implantable cardioverter-defibrillator use in elderly patients receiving cardiac resynchronization: A meta-analysis

BACKGROUND

Implantable cardioverter-defibrillators (ICDs) and cardiac resynchronization therapy (CRT) reduce sudden cardiac death and all-cause mortality in patients with heart failure with reduced ejection fraction (HFrEF). Current guidelines do not suggest any upper age limit for ICD and CRT but recommend avoidance of ICD and CRT in frail patients with a life expectancy of less than 1 year. It remains unclear whether elderly patients undergoing CRT derive the same additional benefit from ICDs as younger patients. We aimed to assess the use of ICDs in elderly compared to younger patients receiving CRT.

METHODS

We searched electronic databases, up to April 11, 2016, for all studies reporting on ICD use stratified by age in patients who received CRT. We used random-effects meta-analysis models to calculate the summarized baseline characteristics and rates of implantation of ICD among patients enrolled in the studies.

RESULTS

We retained six observational studies enrolling 613 patients ≥75 years old and 2810 patients <75 years old. The aggregate mean age was 82.7 years for the elderly patients compared to 66.3 years in the younger patients. There was a significantly lower use of ICDs in elderly patients compared to that in younger patients (37.9% versus 64.3%) (odds ratio: 0.26; 95% confidence intervals: 0.14-0.46; p < 0.0001).

CONCLUSIONS

In conclusion, ICD was less frequently used in patients ≥75 years old receiving CRT compared to younger patients receiving CRT. Future studies that evaluate the efficacy and effectiveness of ICDs in elderly patients with indications for CRT are needed to guide management of this increasing population.

Geographic and Temporal Variation in Cardiac Implanted Electric Devices to Treat Heart Failure

BACKGROUND

Cardiac implantable electric devices are commonly used to treat heart failure. Little is known about temporal and geographic variation in use of cardiac resynchronization therapy (CRT) devices in usual care settings.

METHODS AND RESULTS

We identified new CRT with pacemaker (CRT-P) or defibrillator generators (CRT-D) implanted between 2008 and 2013 in the United States from a commercial claims database. For each implant, we characterized prior medication use, comorbidities, and geography. Among 17 780 patients with CRT devices (median age 69, 31% women), CRT-Ps were a small and increasing share of CRT devices, growing from 12% to 20% in this study period. Compared to CRT-D recipients, CRT-P recipients were older (median age 76 versus 67), and more likely to be female (40% versus 30%). Pre-implant use of β-blockers and angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers was low in both CRT-D (46%) and CRT-P (31%) patients. The fraction of CRT-P devices among all new implants varied widely across states. Compared to the increasing national trend, the share of CRT-P implants was relatively increasing in Kansas and relatively decreasing in Minnesota and Oregon.

CONCLUSIONS

In this large, contemporary heart failure population, CRT-D use dwarfed CRT-P, though the latter nearly doubled over 6 years. Practice patterns vary substantially across states and over time. Medical therapy appears suboptimal in real-world practice.

Causes-of-death analysis of patients with cardiac resynchronization therapy: an analysis of the CeRtiTuDe cohort study

Aims

The choice of resynchronization therapy between with (CRT-D) and without (CRT-P) a defibrillator remains a contentious issue. Cause-of-death analysis among CRT-P, compared with CRT-D, patients could help evaluate the extent to which CRT-P patients would have additionally benefited from a defibrillator in a daily clinical practice.

Methods and results

A total of 1705 consecutive patients implanted with a CRT (CRT-P: 535 and CRT-D: 1170) between 2008 and 2010 were enrolled in CeRtiTuDe, a multicentric prospective follow-up cohort study, with specific adjudication for causes of death at 2 years. Patients with CRT-P compared with CRT-D were older (P < 0.0001), less often male (P < 0.0001), more symptomatic (P = 0.0005), with less coronary artery disease (P = 0.003), wider QRS (P = 0.002), more atrial fibrillation (P < 0.0001), and more co-morbidities (P = 0.04). At 2-year follow-up, the annual overall mortality rate was 83.80 [95% confidence interval (CI) 73.41–94.19] per 1000 person-years. The crude mortality rate among CRT-P patients was double compared with CRT-D (relative risk 2.01, 95% CI 1.56–2.58). In a Cox proportional hazards regression analysis, CRT-P remained associated with increased mortality (hazard ratio 1.54, 95% CI 1.07–2.21, P = 0.0209), although other potential confounders may persist. By cause-of-death analysis, 95% of the excess mortality among CRT-P subjects was related to an increase in non-sudden death.

Conclusion

When compared with CRT-D patients, excess mortality in CRT-P recipients was mainly due to non-sudden death. Our findings suggest that CRT-P patients, as currently selected in routine clinical practice, would not potentially benefit with the addition of a defibrillator.