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AAC is a predictor of obstructive coronary disease and all-cause mortality according to research presented at the poster session at the American College of Cardiology 2010

Abdominal aortic calcification (AAC) is a predictor of obstructive coronary disease and all-cause mortality, and the absence of AAC is a predictor of no obstructive coronary disease, according to research presented at the poster session at the American College of Cardiology 2010 Scientific Sessions.

Dr Steven Simpson (Henry Ford Heart and Vascular Institute, Detroit, MI) and colleagues, with senior author Dr Mouaz Al-Mallah (Henry Ford Heart and Vascular Institute) analyzed noncontrast abdominal scans of 367 patients who were asymptomatic for coronary disease but had a coronary angiography within one year of the CT. The abdominal scans had been ordered for a variety of reasons, such as abdominal pain. Exclusion criteria were previous known CAD , acute ST-elevation MI at the time of angiography, or previous abdominal aortic surgery.

After a median follow-up 27 months, 65 of the patients had died. Univariate analysis showed increasing abdominal aortic calcification was associated with increased mortality. Multivariate analysis showed that AAC adds incremental prognostic information over clinical variables, coronary anatomy, and left ventricular function.

"It's free information, so if somebody is looking at the scan, recording it is probably a useful thing to do," Simpson told heartwire. "It's worth it as a cardiologist to [look at a previous abdominal scan]. It can improve your judgment . . . . Obviously, we're not implying we should order a noncontrast CT of the abdomen for the purposes of a CT coronary calcium score, but since it is free information, we might as well use it. It ups my aggressiveness in some patients."

A second analysis found that 134 of the patients had obstructive CAD. The patients with obstructed coronaries were older and more likely to have hypertension, diabetes, and high cholesterol and take aspirin and statin therapy than the group overall.  AAC scores were significantly higher in subjects with obstructive CAD.

On the other end of the AAC range, only seven of the 62 patients with an AAC score of zero showed obstructive coronary disease on angiography.  AAC's ability to predict obstructive coronary disease had a sensitivity of 96% and a specificity of 31%, with positive and negative predictive values of 58% and 89%, respectively. 

However, the authors caution that their findings must be confirmed in larger group, including lower-risk patients, before AAC can be adopted as a method of risk stratification.

Source: ACC

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