TCT: CCTA can help predict death for symptomatic non-obstructive CAD patients

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SAN FRANCISCO—Plaque morphology, specifically non-calcified and mixed coronary plaques, detected and characterized by coronary CT angiography (CCTA), provides incremental value in predicting all-cause mortality in symptomatic patients with non-obstructive coronary artery disease (CAD), according to a poster presentation at the 2009 Transcatheter Cardiovascular Therapeutics (TCT) scientific symposium this week.

CCTA provides accurate noninvasive diagnosis of CAD, according to Naser Ahmadi, MD, and colleagues from the University of California, Los Angeles. The authors noted that their previous study demonstrated that event-free survival rates of symptomatic patients with CCTA-diagnosed CAD decreased proportionally from normal coronaries (98.3 percent) to non-obstructive CAD (95.2 percent) to obstructive CAD (87.5 percent).

For this study, the researchers analyzed the clinical outcomes of symptomatic patients with non-obstructive (luminal stenosis of less than 50 percent) CAD as determined by CCTA in an outpatient setting.

They prospectively followed 1,102 symptomatic patients (median age, 59 years) with non-obstructive CAD for an average of 78 months.

Overall, Ahmadi and colleagues found that the death rate of patients with non-obstructive CAD was 3.1 percent (34 deaths). However, they found that the death rate increased proportionally from calcified plaque (1.4 percent) to mixed plaque (3.3 percent) to non-calcified plaque (9.1 percent).

They found that non-calcified and mixed plaques were independent predictors of all-cause mortality in patients with non-obstructive CAD.

The authors said that the risk-adjusted hazard ratio of all-cause mortality for CCTA diagnosed non-obstructive CAD was 2.6 percent for non-calcified plaques and 7.5 percent for mixed plaques, as compared with calcified plaques. Also, in patients with non-obstructive CAD, the risk-adjusted event-free survival rate decreased substantially from 98.6 percent for a calcified plaque, to 96.7 percent for mixed plaques to 90.9 percent in subjects with non-calcified plaques.

These results were found consistent regardless of age, gender and conventional risk factors, the authors noted.