Anatomic burden better predictor than ischemic burden

Coronary anatomic burden is a better predictor of death, MI and non-ST-segment elevation acute coronary syndromes (NSTE-ACS) than ischemic burden among patients with coronary artery disease and evidence of myocardial ischemia, a study published online Jan. 15 in JACC: Cardiovascular Interventions found.

Investigators led by G.B. John Mancini, MD, of the University of British Columbia in Vancouver, used data from the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial, which evaluated whether the addition of PCI to optimal medical therapy (OMT) in patients with stable coronary artery disease improved outcomes or offered any mortality benefit.

Mancini and colleagues studied 621 COURAGE participants with baseline quantitative nuclear SPECT and quantitative coronary angiography. They used regression analysis to determine what factors predicted death, MI and NSTE-ACS. They also analyzed ischemic burden during stress SPECT, anatomic burden based on angiography, left ventricular ejection fraction (LVEF) and whether participants were assigned to receive either OMT and PCI or OMT alone.

Anatomic burden and LVEF independently predicted death, MI and NSTE-ACS. Ischemic burden and treatment did not. However, neither anatomic burden nor ischemic burden was able to determine which patients would benefit from an invasive therapeutic strategy, even if the burdens were in combination with each other.

The authors explained what could be the reasons for the findings. “It is apparent that OMT has the ability to reduce ischemic burden, but not as rapidly or extensively as PCI in the short term,” they wrote. “OMT may achieve a sizable reduction in ischemia and comparable reduction in angina-free status over the long term.”

Since both strategies are anti-ischemic, they continued, that may affect the prognostic value of baseline, pretreatment inducible ischemia.

Merck & Co., Pfizer, Bristol-Myers Squibb, Fujisawa, Kos Pharmaceuticals, Datascope, AstraZeneca, Key Pharmaceutical, Sanofi-aventis, First Horizon and GE Healthcare provided funding for this research.