JACC: Myocardial perfusion imaging by CMR is efficacious for both sexes

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In addition to avoiding exposure to ionizing radiation, stress cardiac MR (CMR) myocardial perfusion imaging is an effective and robust risk-stratifying tool for patients of either sex presenting with possible ischemia, according to a study in the August issue of JACC: Cardiovascular Imaging.

CMR provides a radiation-free assessment of cardiac function, myocardial ischemia and MI at high spatial resolution and tissue contrast, according to the authors. Recent studies have shown that stress CMR provides effective cardiac prognostication in patients with chest pain, but it is unclear whether this robust association with clinical events can be extended to a similar degree to patients of either sex.

The major aim of the study was to test the hypothesis that stress CMR imaging can provide robust prognostic value in women presenting with suspected ischemia, to the same extent as in men, explained Otavio R. Coelho-Filho, MD, and colleagues of Brigham and Women's Hospital in Boston. 

Compelling evidence indicates that women with coronary artery disease (CAD) experience worse outcomes than men owing to a lack of early diagnosis and management. Numerous clinical studies have shown that stress CMR detects evidence of myocardial ischemia and infarction at high accuracy, the researchers said. Compared with nuclear scintigraphy, CMR is free of ionizing radiation, has high spatial resolution for imaging small hearts, and overcomes breast attenuation artifacts, which are substantial advantages when imaging women for CAD.

Coelho-Filho et al performed stress CMR in 405 patients (168 women, mean age 58 years) referred for ischemia assessment. CMR techniques included cine cardiac function, perfusion imaging during vasodilating stress and late gadolinium-enhancement imaging. All patients were followed for major adverse cardiac events (MACE).

At a median follow-up of 30 months, MACE occurred in 9 percent of patients, including 21 cardiac deaths and 15 acute MIs, the authors wrote. 

In women, CMR evidence of ischemia (ISCHEMIA) demonstrated strong association with MACE. While women with ISCHEMIA(+) had an annual MACE rate of 15 percent, women with ISCHEMIA(–) had very low annual MACE rate (0.3 percent), which was not statistically different from the low annual MACE rate in men with ISCHEMIA(–) (1.1 percent). CMR myocardial ischemia score was the strongest multivariable predictor of MACE in this cohort, for both women and men, indicating robust cardiac prognostication regardless of sex, according to the researchers. 

“CMR myocardial perfusion imaging provides robust prognostication for cardiac events in both women and men,” Coelho-Filho and colleagues wrote. “A CMR study without evidence of myocardial ischemia indicates a very low risk of MACE and cardiac death in women. The prognostic association of CMR myocardial perfusion imaging with MACE appeared to be as strong in women as in men, and CMR offers the advantage of freedom from using ionizing radiation and high image resolution.”