Effectiveness of cardiac resynchronization therapy by the frequency of revascularization procedures in ischemic cardiomyopathy patients

Background: It is not known whether the number of revascularizations modifies clinical outcomes in patients with ischemic cardiomyopathy (ICM) implanted with cardiac resynchronization therapy defibrillator (CRT-D) vs. an implantable cardioverter-defibrillator (ICD)-only. Methods: In Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy (MADIT-CRT), we evaluated the effect of CRT-D vs. ICD-only on heart failure (HF) or death, on ventricular tachycardia (VT), ventricular fibrillation (VF) or death, and on reverse remodeling in 592 ICM patients with left bundle branch block, by the number of pre-enrollment revascularizations (0, 1 or >= 2 revascularizations). Results: There was a risk reduction of HF/death with CRT-D vs. ICD-only in all three sub-groups: ICM with no need for revascularization (HR 0.51 [0.26-1.02]; p = 0.055), ICM with 1 revascularization (HR 0.45 [0.30-0.70]; p < 0.001), and ICM with 2 or more revascularizations (HR 0.37 [0.20-0.66]; p < 0.001). Similarly, there was a risk reduction of VT//VF/death with CRT-D vs. ICD-only in patients with no need for revascularization (HR 0.55 [0.31-0.99]; p = 0.044); with 1 revascularization (HR 0.77 [0.51-1.18]; p = 0.23); or with = 2 revascularizations (HR 0.63 [0.34-1.17]; p = 0.14). There was a similar degree of left ventricular reverse remodeling in all three sub-groups (p > 0.05 for LVESV, LVEDV, and LAV percent change at 1-year follow-up). Conclusions: In ICM patients, CRT-D is associated with a reduction in HF or death and VT/VF or death - irrespective of the frequency of pre-enrollment revascularization procedures - and is accompanied by a similar degree of beneficial left ventricular reverse remodeling.