Inducible Myocardial Ischemia and Outcomes in Patients with Coronary Artery Disease and Left Ventricular Dysfunction

OBJECTIVES: To test the hypotheses that ischemia during stress testing has prognostic value and that it identifies those coronary artery disease (CAD) patients with left ventricular (LV) dysfunction who derive the greatest benefit from coronary artery bypass graft surgery (CABG) compared to medical therapy. The clinical significance of stress-induced ischemia in patients with CAD and moderately to severely reduced LV ejection fraction (EF) is largely unknown.

METHODS: The Surgical Treatment of IsChemic Heart failure (STICH) trial randomized patients with CAD and EF ≤35% to CABG or medical therapy. In this study, we assessed the outcomes of those STICH patients who underwent either a radionuclide (RN) stress test or a dobutamine stress echocardiogram (DSE). A test was considered positive for ischemia by RN if the summed difference score (difference in tracer activity between stress and rest) was ≥ 4 or if ≥2 of 16 segments were ischemic during DSE. Clinical endpoints were assessed by intention-to-treat during a median follow-up of 56 months.

RESULTS: Of the 399 study patients (51 women, mean EF 26±8%), 197 were randomized to CABG and 202 to medical therapy. Myocardial ischemia was induced during stress testing in 256 patients (64% of the study population). Patients with and without ischemia were similar in age, multi-vessel CAD, previous myocardial infarction, LV EF, LV volumes, and treatment allocation (all p=NS). There was no difference between patients with vs. those without ischemia in all-cause mortality (hazard ratio: 1.08; 95% CI: 0.77-1.50; p=0.66), cardiovascular mortality, or all-cause mortality plus cardiovascular hospitalization. There was no interaction between ischemia and treatment for any clinical endpoint.

CONCLUSIONS: In CAD with severe LV dysfunction, inducible myocardial ischemia does not identify patients with worse prognosis or those with greater benefit from CABG over optimal medical therapy. 

PMID: 23500234

Posted in Nuclear Imaging and tagged , , , , , , .

One Comment

  1. The STICH trial was always difficult to reach concrete conclusions from but it seems even more difficult now!Reversible ischaemia on nuclear scanning or echo didn’t predict benefit from CABG in this analysis.

    Although it is well established in clinical practice, there is actually very little evidence that patients with reversible ischaemia do better with revascularisation. The only evidence is from the COURAGE nuclear substudy which has some serious limitations.

    We need the ISCHEMIA trial!

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