Long-term outcome after upgrade to cardiac resynchronization therapy: A propensity score-matched analysis
Sander Trenson1,2,3,4, Gabor Voros1,4, Pieter Martens5
1Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium.
Insights
Upgrading to cardiac resynchronization therapy (CRT) in heart failure patients is linked to worse long-term outcomes compared to new CRT implants. This difference highlights distinct patient populations rather than a therapy effect.
Area of Science:
- Cardiology
- Electrophysiology
- Heart Failure Management
Background:
- Cardiac resynchronization therapy (CRT) is a key treatment for heart failure patients with wide QRS complexes.
- Limited data exist on the long-term outcomes specifically for patients upgraded to CRT from other devices.
Purpose of the Study:
- To compare the long-term outcomes of patients undergoing de novo CRT implantation versus those upgraded to CRT.
- To investigate the impact of CRT upgrades on mortality, heart transplantation, ventricular assist device implantation, and heart failure admissions.
Main Methods:
- Retrospective analysis of a multicenter registry including 2275 patients with de novo or upgraded CRT.
- Mean follow-up of 3.6 years; primary endpoint: all-cause mortality, heart transplant, or VAD implantation.
- Secondary endpoint: heart failure admission; analyses included multivariable Cox regression and propensity score matching (PSM).
Main Results:
- Patients upgraded to CRT (n=605) had distinct characteristics, including less female representation, more ischemic cardiomyopathy, and worse renal function.
- The composite endpoint incidence was higher in the CRT upgrade group (10.8%/year) vs. de novo CRT (7.1%/year).
- After PSM, CRT upgrade was associated with increased risk for the composite endpoint (HR 1.35) and heart failure admission (HR 1.74), particularly from ICD.
Conclusions:
- Long-term outcomes after CRT upgrade differ significantly from de novo CRT implantation, especially when upgrading from an implantable cardioverter-defibrillator (ICD).
- Observed outcome differences likely reflect baseline patient population disparities rather than a direct causal effect of the upgrade therapy itself.
Aim:
Cardiac resynchronization therapy (CRT) is a cornerstone in the management of chronic heart failure in patients with a broad or paced QRS. However, data on long-term outcome after upgrade to CRT are scarce.
Methods And Results:
This international, multicentre retrospective registry included 2275 patients who underwent a de novo or upgrade CRT implantation with a mean follow-up of 3.6 ± 2.7 years. The primary composite endpoint included all-cause mortality, heart transplantation, or ventricular assist device implantation. The secondary endpoint was first heart failure admission. Multivariable Cox regression and propensity score matching (PSM) analyses were performed. Patients who underwent CRT upgrade (n = 605, 26.6%) were less likely female (19.7% vs. 28.8%, p < 0.001), more often had ischeemic cardiomyopathy (49.8% vs. 40.2%, p < 0.001), and had worse renal function (median estimated glomerular filtration rate 50.3 ml/min/1.73 m2 [35.8-69.5] vs. 59.9 ml/min/1.73 m2 [43.0-76.5], p < 0.001). The incidence rate of the composite endpoint was 10.8%/year after CRT upgrade versus 7.1%/year for de novo implantations (p < 0.001). PSM for the primary endpoint resulted in 488 pairs. After propensity score matching, upgrade to CRT was associated with a higher chance to reach the composite endpoint (multivariable hazard ratio [HR] 1.35, 95% confidence interval [CI] 1.08-1.70), for both upgrade from pacemaker (multivariable HR 1.33, 95% CI 1.03-1.70) and implantable cardioverter-defibrillator (ICD) (multivariable HR 1.40, 95% CI 1.01-1.95). PSM for the secondary endpoint resulted in 277 pairs. After PSM, upgrade to CRT was associated with a higher chance for heart failure admission (HR 1.74, 95% CI 1.26-2.41).
Conclusion:
In this retrospective analysis, the outcome of patients who underwent upgrades to CRT differed significantly from patients who underwent de novo CRT implantation, particularly for upgrades from ICD. Importantly, this difference in outcome does not imply a causal relation between therapy and outcome but rather a difference between two different patient populations.
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