Download this article's Factoid in PDF (& PPT for Gold Subscribers)

Coronary computed tomographic angiography (CTA) provides accurate long-term diagnostic information in patients with suspected coronary artery disease (CAD), especially among those with no coronary lesions, according to findings published in the July 2012 issue of JACC: Cardiovascular Imaging.

Daniele Andreini, MD, of the Centro Cardiologico Monzino (Milan, Italy), and colleagues used CTA to prospectively analyze 1,196 patients with suspected CAD from February 2005 to March 2008. Patients were separated into 3 groups:

• Normal: No coronary plaques
• Nonobstructive CAD: Mild (< 50%) lesions
• Obstructive CAD: Obstructive (> 50%) lesions

Accurate Prognostication

After a mean follow-up period of 52 months, there were a total of 475 events recorded in 412 patients, 136 hard events (18 cardiac deaths and 118 nonfatal MIs), and 123 late revascularizations. Multivariate analysis found several CTA characteristics, including multivessel disease and left main CAD, to be predictive of events combined with ≥ 50% obstructive CAD (table 1).

Table 1. Multivariate Predictors of Events on CTA^a

^a P < 0.0001 for all.

No events occurred in patients with normal coronary arteries. In patients with nonobstructive CAD, overall hard- and all-event-free survival were 88% and 72%, respectively; while in patients with obstructive CAD, they were 54% and 31% (P = 0.0001). For all events, cumulative event-free survival was 48% with 1-vessel disease, 14% with 2-vessel disease, 16% with 3-vessel disease, and 25% with left main CAD (P = 0.0001).

Long-term Utility Confirmed

“The main additional value of [this] paper in comparison with the current literature is the follow-up of more than 4 years, versus a mean follow-up of 2 years in other studies,” Dr. Andreini told TCTMD in an e-mail communication. “Our data confirm at long-term follow-up the excellent prognosis of patients with normal CTA, as previously demonstrated by other shorter and smaller studies.”

The authors write that the 100% event-free survival rate among those with no CAD on CTA is an important result. “This diagnostic modality can be used to reassure patients with suspected CAD who have equivocal results of exercise ECG, stress single-photon emission computed tomography imaging, and stress echocardiography without the need of invasive coronary angiography, about their outcome,” they report, adding that the major drawback of CTA versus other modalities is radiation exposure.

The investigators also highlighted the ability of CTA to show divergent event-free survival curves based on the extent of disease “in addition to having a prognostic role when obstructive CAD was detected.”

Since the study was confined to a single center, the authors noted that this may limit extrapolation of the results to the general population. Also, the identification of patients with obstructive CAD could have inflated the revascularization rate, which accounted for a large proportion of the composite cardiac event endpoint. In spite of these limitations, Dr. Andreini observed that “a patient without history of CAD or other known cardiac disease and with no coronary lesions at CT coronary angiography has an excellent prognosis in terms of MACE.”

Study Details

Patients with events averaged 65 years of age and were more often male and diabetic. Indications for CTA included chest pain (43%), an abnormal or equivocal stress test (29%), and multiple cardiac risk factors (28%). Mean pre-CTA probability of CAD was 42.5%.

Related Stories:

• Coronary CTA Effective, Efficient in Ruling Out Patients with Suspected ACS
• Coronary CTA Can Serve as Gatekeeper to Invasive Angiography
• CT Angiography Rules Out Stenosis in Patients at Low-Intermediate CAD Risk