Cardiac Risk in Diabetes Often Overestimated

Cardiac Risk in Diabetes Often Overestimated

DENVER – Diabetes patients with stable symptoms of coronary artery disease appear to have a lower cardiac event risk than previously thought.

The yearly rate of cardiovascular death or nonfatal MI was just 2.4% in a series of 444 consecutive diabetes outpatients with symptoms suggestive of coronary artery disease (CAD) who underwent exercise treadmill or pharmacologic stress single-photon emission computed tomography (SPECT) myocardial perfusion imaging. The cardiovascular death rate of 0.4% per year and the nonfatal MI rate of 2.0% per year were surprisingly low, given that 39% of subjects had known CAD and the rest had symptoms suggestive of CAD, Dr. Jamieson M. Bourque noted at the annual meeting of the American Society of Nuclear Cardiology.

The explanation may be found at least in part in contemporary evidence-based intensive medical management for risk reduction in this traditionally high-risk population, added Dr. Bourque of the University of Virginia, Charlottesville.

Of the 444 symptomatic diabetes patients, 78.5% had no inducible ischemia on stress SPECT myocardial perfusion imaging, 16.5% had 1%-9% left ventricular ischemia, and 5% had left ventricular ischemia of at least 10%. Again, these are lower rates than would be expected based on historical data taken from the era before aggressive risk factor modification in patients with diabetes and CAD symptoms.

During a median 2.4 years of follow-up, the combined rate of cardiovascular death, nonfatal MI, or revascularization more than 4 weeks after myocardial perfusion imaging was 32% in patients with at least 10% left ventricular ischemia on their presenting SPECT study, 14% in those with 1%-9% ischemia, and 8% in those with no ischemia.

Patients who achieved at least 10 METs (metabolic equivalents) on the treadmill during testing had the best prognosis. The sole event that occurred in this subgroup was a late revascularization.

In all, 60% of hard cardiac events occurring in this study were in patients with no perfusion defects. This points to the need for improved patient selection and risk stratification techniques in diabetes patients, according to Dr. Bourque.

He declared having no financial conflicts.