Abdominal aortic atherosclerosis MRI measurements predicted MI, stroke

In a study of more than 2,000 adults, MRI measurements of abdominal aortic atherosclerosis were predictive of future adverse CV events.

“This is an important study because it demonstrates that atherosclerosis in an artery outside the heart is an independent predictor of adverse cardiovascular events,” Christopher D. Maroules, MD, a radiology resident at the University of Texas Southwestern Medical Center, Dallas, said in a press release. “MRI is a promising tool for quantifying atherosclerosis through plaque and arterial wall thickness measurements.”

Maroules and colleagues analyzed abdominal aortic MRIs at 1.5 tesla of 2,122 adults (mean age, 44 years; 56% women) who participated in the multi-ethnic, population-based Dallas Heart Study. Two measurements were obtained from the MRIs: mean abdominal aortic wall thickness and aortic plaque burden. Primary endpoints included CV death, nonfatal cardiac events and nonfatal extracardiac vascular events during a mean follow-up period of 7.8 years.

Overall, 143 participants (6.7%) experienced a CV event during follow-up. Of those events, 1.6% were fatal, 3.4% were nonfatal cardiac events, such as MI, and 2.2% were nonfatal extracardiac vascular events, such as stroke.

Using MRI measurements, increased mean aortic wall thickness correlated with all three types of events, and increased aortic plaque burden correlated with nonfatal extracardiac vascular events. When evaluated as a continuous variable, mean aortic wall thickness was associated with increased risk for composite CV events (HR=1.28 per 1 SD increase, equivalent to 0.33-mm increase; P=.001) and nonfatal extracardiac vascular events (HR=1.52 per 1 standard deviation [SD]; P<.001.) Aortic plaque burden was not associated with increased risk for composite events when analyzed as a categorical or continuous variable; however, it was associated with significantly increased risk for nonfatal extracardiac vascular events (HR=1.46 per 1 SD increase, equivalent to 4.2-unit increase; P=.03).

Although aortic atherosclerosis has been previously linked to CV events and mortality, the studies evaluated aortic calcification using spine radiography or CT. However, those methods may expose patients to ionizing radiation and can overlook early atherogenic changes. Using MRI to measure mean arterial wall thickness and aortic plaque burden carries neither of those drawbacks, according to the researchers.

“These MRI measurements may add additional prognostic value to traditional cardiac risk stratification models,” Maroules said in the press release.

For more information:

Maroules CD. Radiology. 2013;doi:10.1148/radiol.13122707.

Disclosure: Maroules reports no relevant financial disclosures.