Abstract 2432: The Effects of Revascularization on Survival and VT/VF Frequency in the ICD Population
Background: The MADIT II Investigators reported no benefit of ICD therapy on survival in the subgroup undergoing coronary artery revascularization within 6 months of ICD implantation. Whether the type or completeness of coronary artery revascularization procedure influences ventricular tachycardia/ventricular fibrillation (VT/VF) occurrence following ICD implantation is unknown. We compared the type of coronary artery revascularization procedure and completeness of coronary artery revascularization on VT/VF occurrence and VT/VF frequency following ICD implantation.
Methods: The study population consisted of 389 ICD patients with documented coronary artery disease followed in the Calgary Health Region (CHR). All data on VT/VF occurrence was prospectively collected. Details related to coronary revascularization procedure (type, completeness) were retrieved from institutional databases. Survival free from VT/VF and the frequency of VT/VF were compared between patients not undergoing revascularization (n=172) and patients undergoing coronary artery bypass grafting (CABG)(n=107) or percutaneous coronary intervention (PCI)(n=109).
Results: Survival free from VT/VF was significantly improved in the PCI group (626±805 days) compared to non-revascularized group (390±588 days)( p=0.03). Results were intermediate for the CABG group (515±581 days) compared to the non-revascularized group (p=NS). The mean frequency of VT/VF for PCI patients was significantly lower (0.22±0.78 episodes/month) compared to the non-revascularization group (0.48±1.16 episodes/month, p<0.04). The mean frequency of VT/VF was similar in the CABG (0.60±1.95 episodes/month) and non-revascularization groups (p=0.47). There was a trend for patients undergoing complete revascularization to experience fewer VT/VF episodes (0.22±0.61 episodes per month) compared to those only partially revascularized (0.60±3.79 episodes per month, p=0.06).
Conclusions: Revascularization by PCI is associated with improved survival free from VT/VF following ICD implantation and a significant reduction in the frequency of VT/VF episodes over time.