The effect of revascularization on mortality and risk of ventricular arrhythmia in patients with ischemic cardiomyopathy

Revascularization and Left Ventricular Dysfunction for ICD Eligibility

Common triggers for sudden cardiac death (SCD) are transient ischemia, hemodynamic fluctuations, neurocardiovascular influences, and environmental factors. SCD occurs rapidly when sinus rhythm degenerates into ventricular tachycardia (VT) and/or ventricular fibrillation (VF), followed by asystole. Such progressive worsening of the cardiac rhythm is in most cases observed in the setting of ischemic heart disease and often associated with advanced left ventricular (LV) impairment. Revascularization prevents negative outcomes including SCD and heart failure (HF) due to LV dysfunction (LVD). The implantable cardioverter-defibrillator (ICD) on top of medical therapy is superior to antiarrhythmic drugs for patients with LVD and VT/VF. The beneficial effects of ICD have been demonstrated in primary prevention of SCD as well. However, yet debated is the temporal management for patients with LVD who are eligible to ICD prior to revascularization, either through percutaneous or surgical approach. Restoration of coronary blood flow has a dramatic impact on adverse LV remodeling, while it requires aggressive long-term antiplatelet therapy, which might increase complication for eventual ICD procedure when percutaneous strategy is pursued; on the other hand, when LV and/or multiorgan dysfunction is present and coronary artery bypass grafting is chosen, the overall risk is augmented, mostly in HF patients. The aims of this review are to describe the pathophysiologic benefits of revascularization, the studies addressing percutaneous, surgical or no revascularization and ICD implantation, as well as emerging defibrillation strategies for patients deemed at transient risk of SCD and/or at higher risk for transvenous ICD implantation.

Impact of revascularization guided by functional testing in ischaemic cardiomyopathy

AIMS

The burden of ischaemia is a risk factor for adverse outcomes in ischaemic cardiomyopathy (ICM) but is not systematically tested when deciding on revascularization. Limited data exists in patients with ICM regarding the interaction between ischaemia and early coronary revascularization (ECR). This study sought to determine if the burden of ischaemia modifies the outcomes of ECR in ICM.

METHODS AND RESULTS

Consecutive patients with ICM (left ventricular ejection fraction < 40%) with a stress-rest gated single-photon emission computed tomography (N = 747) were followed-up for ECR and major cardiovascular events (MACEs, cardiovascular death, myocardial infarction, or heart failure hospitalization). A 1:1 matched population was selected using a propensity score for ECR. The interaction between ischaemia and ECR was evaluated in the matched cohort. In the initial cohort, 131 patients underwent ECR. Of them, 109 were matched to non-ECR patients. After a median follow up of 4.1 years, 102 (46.8%) patients experienced a MACE. The effect of revascularization on MACE was dependent of the percent of ischaemia (P for the interaction at 10% ischaemia = 0.021), so that a trend towards a decreased risk of MACE was seen in patients with >10% of ischaemia [hazard ratio (HR) = 0.59 (0.30-1.18)], whereas a non-significant increase of MACE was observed in those with <10% ischaemia (HR = 1.67 [0.94-2.96]).

CONCLUSIONS

In a contemporary cohort of patients with ICM, the beneficial effects of ECR may be mediated by the percent of ischaemia. This study supports stress testing in ICM and an ischaemia-guided approach for ECR.