Multiple Comorbidities and Response to Cardiac Resynchronization Therapy: MADIT-CRT Long-Term Follow-Up
Emily P Zeitler1, Daniel J Friedman1, James P Daubert1
1Cardiology Division, Duke University Hospital and Duke Clinical Research Institute, Durham, North Carolina.
Insights
Cardiac resynchronization therapy (CRT) provides benefits for heart failure patients, even with multiple comorbidities. The study found CRT-D offers significant advantages over ICD alone, regardless of patient complexity.
Area of Science:
- Cardiology
- Electrophysiology
- Heart Failure Management
Background:
- Limited data exists on cardiac resynchronization therapy (CRT) efficacy in patients with multiple comorbidities.
- Understanding treatment benefits in complex patient populations is crucial for clinical decision-making.
Purpose of the Study:
- To evaluate the association between multiple comorbidities and the benefits of CRT compared to implantable cardioverter-defibrillator (ICD) alone.
- To assess how comorbidity burden influences reverse remodeling and clinical outcomes in CRT recipients.
Main Methods:
- Analysis of 1,214 patients from the MADIT-CRT trial with left bundle branch block (LBBB) and varying comorbidity counts (0 to ≥3).
- Comorbidities included renal dysfunction, hypertension, diabetes, coronary artery disease, atrial/ventricular arrhythmias, smoking, and cerebrovascular accident.
- Adjusted analyses examined risks of heart failure (HF) events or death and changes in left ventricular volumes, ejection fraction, left atrial volume, and LV dyssynchrony.
Main Results:
- An inverse relationship was observed between comorbidity burden and improvements in left ventricular (LV) remodeling parameters and LV dyssynchrony.
- Increasing comorbidity burden correlated with a higher risk of death or HF events, irrespective of treatment (CRT-D vs. ICD).
- While no significant interaction was found for CRT-D vs. ICD benefit on HF/death risk, absolute risk reduction with CRT-D appeared greater in patients with higher comorbidity burden.
Conclusions:
- Despite variations in reverse remodeling and HF/death risk across comorbidity groups, the overall clinical benefits of CRT-D are not compromised by a higher comorbidity burden.
- Cardiac resynchronization therapy with defibrillator (CRT-D) remains a beneficial treatment option for patients with left bundle branch block and multiple comorbidities compared to ICD alone.
Background:
Data regarding cardiac resynchronization therapy (CRT) in patients with multiple comorbidities are limited.
Objectives:
This study evaluated the association of multiple comorbidities with the benefits of CRT over implantable cardioverter-defibrillator (ICD) alone.
Methods:
We examined 1,214 MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy) study patients with left bundle branch block (LBBB) and 0, 1, 2, or ≥3 comorbidities, including renal dysfunction, hypertension (HTN), diabetes, coronary artery disease, history of atrial arrhythmias, history of ventricular arrhythmias, current smoking, and cerebrovascular accident. In an adjusted analysis, we analyzed risk of heart failure (HF) events or death by comorbidity group in all patients and in patients with CRT with defibrillator (CRT-D) versus ICD. Then we examined percent change in left ventricular (LV) end-diastolic volume, LV end-systolic volume, LV ejection fraction, left atrial volume, and LV dyssynchrony at 1-year in CRT-D patients by comorbidity group.
Results:
There was an inverse relationship between comorbidity burden and improvements in LV end-systolic volume, LV end-diastolic volume, left ventricular ejection fraction, left atrial volume, and LV dyssynchrony. In an adjusted model, there was an increasing risk of death or nonfatal HF events with increasing comorbidity burden regardless of treatment group (p < 0.001). During a mean follow-up of 4.65 years, there was no interaction with respect to comorbidity burden and the benefit of CRT-D versus ICD only for death or nonfatal HF events (interaction p = 0.943). In the groups with greatest comorbidity burden (2 and ≥3), the absolute risk reduction associated with CRT-D over ICD alone appeared greater than that seen for groups with less comorbidity burden (0 and 1).
Conclusions:
During long-term follow-up of MADIT-CRT study patients with LBBB randomized to CRT-D, there were differences in HF or death risk and in the degree of reverse remodeling among comorbidity groups. However, the burden of comorbidity does not appear to compromise the clinical benefits of CRT-D compared with ICD alone.
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