Long-term prognostic value of inducible myocardial ischemia in patients with severe ventricular dysfunction undergoing coronary artery bypass graft surgery

Abstract

The evaluation of inducible myocardial ischemia (IMI) has been used to identify patients in whom revascularization will provide a clinical benefit. This arises largely from studies in patients with normal or slightly reduced left ventricular ejection fraction (LVEF). There is scarce information regarding the search for IMI in patients with severe LVEF undergoing coronary artery bypass graft surgery (CABG) and its relation to long-term survival. Objective: To evaluate the long-term prognostic value of IMI in patients with severe LVEF deterioration under elective isolated CABG. Methods: Comparative retrospective observational study on a database whose information was collected prospectively from 2004 to 2016. Patients with LVEF of less than 35% were included consecutively,
with evaluation of IMI by echo stress (ischemia in ≥2 segments) or gated -SPECT (≥4 segments) prior to an isolated non-urgent CABG. As a primary endpoint, mortality from all causes was analyzed in long-term follow-up. As a secondary point, a combination of in-hospital mortality or low cardiac output syndrome (LCOS) was evaluated. Results: Ninety-two patients were included, of whom 59.7% had IMI (71.8% gated-SPECT, and 28.2% through echo stress). The majority were males, and the mean age was 64.4 ± 8.4 years for the IMI group and 65 ± 6.5 years for the group without IMI (P = 0.07). There were no differences in the baseline characteristics and pharmacological treatment of both groups. The median follow-up was 19 months (PCTL 25-75, 1.2-84.5 months). At follow-up, mortality from all causes was 21.8% in the group of patients with IMI, and 37.8% in those without IMI (Log rank test P=0.034), but after a Cox regression analysis, when in-hospital complications were taken into account, IMI was not an independent variable (HR 0.32 (0.22-1.65)). Regarding the secondary endpoint of in-hospital mortality or low cardiac output syndrome (LCOS), it was also
significantly more frequent in the group without IMI (24.3% vs. 9.1%, respectively, P = 0.046). Conclusions: The presence of IMI prior to surgery in patients with severe impairment of LVEF undergoing CABG allows the identification of a group of patients with a better prognosis, presenting a lower rate of the composite event of in-hospital mortality or LCOS, and also lower mortality in the follow-up,
losing statistical significance when in-hospital complications are taken into account.