Early revascularization by PCI or CABG in patients with stable coronary artery disease was associated with higher early risks of cardiovascular events, but lower long-term risks, compared with a conservative strategy of initial medical therapy, according to findings from ISCHEMIA presented Nov. 11 at AHA 2023 and simultaneously published in JACC. Researchers noted that early risks were greatest following CABG, due to protocol-defined procedural myocardial infarctions (MIs).

For this ISCHEMIA analysis, researchers separately looked at outcomes of ISCHEMIA patients without preceding primary outcome events who were assigned to the invasive strategy cohort receiving either PCI or CABG. Patients were identified as “INV-PCI” (n=1,500) or “INV-CABG” (n=512) at the time of revascularization. The ISCHEMIA primary outcome – a composite of cardiovascular death, protocol-defined MI or hospitalization for unstable angina, heart failure or resuscitate cardiac arrest – was used for the analysis.

Overall findings showed primary outcome events occurred in 16.4% of INV-CABG patients and in 9.8% of INV-PCI patients over approximately three years of follow-up. Of these, 48 events (57.1%) and 31 events (21.1%) occurred within 31 days after CABG and PCI, respectively. In both cases the majority of early events involved procedural MIs (40 in the INV-CABG group; 23 in the INV-PCI group).

In comparison, primary outcome events occurred in 13.6 percent of patients assigned to the conservative strategy, 6.3% of which occurred within 30 days of randomization. Researchers said adjusted primary outcome risks were higher after both CABG and PCI within 30 days (16.25 and 2.99) and lower after (0.63 and 0.66).

“These observations illustrate the impact of outcome definitions and timing on the perceived risks of different interventions and underscore the need to consider in detail the definitions and clinical importance of individual events that constitute a composite outcome when interpreting clinical trial results,” said Bjorn Redfors, MD, PhD, et al. They added that “more research is required to refine the optimal definition for procedural MI after revascularization, and to determine whether the criteria should be similar or different after PCI and CABG.”