Survival benefit of coronary revascularization after myocardial perfusion SPECT: The role of ischemia

Survival benefit of revascularization over medical therapy (MT) in patients with stable-ischemic-heart-disease (SIHD) is uncertain. We evaluated the prognostic effects of revascularization in patients with SIHD undergoing single-photon-emission-computed-tomography myocardial-perfusion imaging (SPECT-MPI).

Methods: Of 47,894 patients, 7,973 had ischemia ≥5% of the left ventricle. Of these, 1,837 underwent early-revascularization (≤60 days after SPECT-MPI). The rest were MT sub-group. Follow-up period was 4.04±1.86years. Statin-therapy intensity and adherence were assessed. Outcomes were all-cause mortality, death+non-fatal myocardial-infarction (MI) and MACE [major adverse cardiac-event=death+MI+late-revascularization (>60 days after SPECT-MPI)].

Results: Among patients with moderate-severe ischemia (≥10%), death-rate was lower in early-revascularization compared to MT sub-group (1.42%/year vs 3.12%/year, adjusted-hazard-ratio (HR) 0.67(95% CI 0.50-0.90, p=0.008). Death+MI and MACE rates were also lower, adjusted-HR 0.69(0.55-0.88, p=0.003) and 0.80(0.69-0.92, p=0.003). Revascularization was beneficial in optimal-statin-therapy subgroup (death-rate 1.04%/year vs. 2.36%/year, adjusted-HR 0.51(0.30-0.86, p=0.012). In mild ischemia (5%-9%), revascularization did not improve survival or MI-free survival, and was associated with higher MACE-rate (8.86%/year vs. 7.67%/year, adjusted-HR 1.30(1.12-1.52, p<0.001).

Conclusion: Compared to MT, revascularization was associated with reduced risk of death, death+MI and MACE in patients with moderate-severe ischemia, incremental over optimal-statin-therapy. In mild ischemia, revascularization was associated with higher risk of MACE, driven-by late-revascularization, with no impact on death and death+MI.