DISCUSSION
sudden death, death, ventricular arrhythmia, nonfatal arrhythmias, ischemia, ventricular arrhythmias, ischemic left ventricular dysfunction, left ventricular dysfunction, arrhythmias, infarction
SUDDEN DEATH, SCAR, IMPAIRED LEFT VENTRICULAR FUNCTION, VENTRICULAR ARRHYTHMIA, ISCHEMIA, EVENT, EVENTS, LEFT VENTRICULAR DYSFUNCTION, NONSUSTAINED VENTRICULAR ARRHYTHMIAS, ARRHYTHMIAS, INFARCTION
In this analysis of the REVIVED-BCIS2 trial, a strategy of PCI in addition to OMT was not associated with a reduction in all-cause mortality or aborted sudden death in patients with ischemic left ventricular dysfunction. Furthermore, PCI was not associated with a reduction in the incidence of sustained ventricular arrhythmias or appropriate ICD therapies. The results suggest that patients with stable ischemic left ventricular dysfunction who are on guideline-directed medical therapy should not undergo PCI with the sole aim of reducing potentially fatal arrhythmias. The findings also challenge the widespread practice of undertaking CABG or PCI in most patients who are candidates for ICD implantationIn the preliminary report of the REVIVED-BCIS2 trial, appropriate ICD therapies tended to be less frequently observed at 2 years in patients assigned to have PCI, in the subgroup who had a device implanted at baseline or within the first 90 days.To the best of our knowledge, ours is the first trial to assess the effect of randomized allocation to PCI on arrhythmic risk in patients with stable ischemic left ventricular dysfunction. In the CABG PATCH trial, patients with ischemic left ventricular dysfunction and no history of ventricular arrhythmia who were undergoing CABG were randomized to receive either a surgically implanted ICD or no ICD; at an average follow-up of 32 months, there was no significant difference in all-cause mortality between groups.Site-reported completeness of revascularization in the REVIVED-BCIS2 trial was high, which would be expected to appreciably reduce the burden of inducible ischemia, particularly because the protocol recommended revascularization of all diseased vessels subtending viable myocardium. In this context, the inability to reduce all-cause mortality or aborted sudden death with PCI may indicate that ischemia is less important in the genesis of ventricular arrhythmias than scar, although the relative importance of these 2 factors cannot be definitively discerned without information on the burden and distribution of each. Furthermore, we cannot discount the possibility that PCI may cause periprocedural infarction, which could partially offset the benefit of reducing ischemic burden.Our findings support those of the ISCHEMIA (International Study of Comparative Health Effectiveness With Medical and Invasive Approaches) investigators, who found no difference in all-cause mortality between patients with documented ischemia who underwent revascularization and those treated with medical therapy alone, although that trial excluded patients with impaired left ventricular function.Our study has some limitations. Because more than half of all patients received an ICD or CRT device, the trial has provided important insights into the potential mechanism of death and aborted sudden death in these cases, however, we had less ability to capture nonfatal arrhythmias in patients without devices and may have underestimated the overall event rate. This may have reduced statistical power, but given that the proportions of patients with devices were similar in the 2 trial groups, our estimation of treatment effect is unlikely to have been affected. The number of events detected provides 85% power to detect or exclude a hazard ratio of 0.70, in line with our initial power calculation, although we cannot exclude a smaller treatment effect with PCI. Second, the decision to implant a device was at the discretion of treating physicians and was based on clinical factors and regional differences in policy. Although there was no significant difference in the overall rates of device implantation over the course of the trial, it should be noted that the timing of implantation was not identical in both groups (Figure 