Abstract 373: CT Coronary Angiography for Patient Triage to Invasive Angiography: Comparison of Performance in Patients With and Without Prior Noninvasive Stress Tests
Background: Functional testing in patients with suspected coronary artery disease (CAD) may yield equivocal results, and the role of CT angiography (CTA) in patients with equivocal stress testing has not been determined. We compared the diagnostic yield of CTA and need for invasive angiography and revascularization in patients with and without prior equivocal stress tests.
Methods: Consecutive patients referred for outpatient CTA for evaluation of suspected CAD after an equivocal stress test or without prior testing were included. CTA studies were performed on a 64 detector scanner (Toshiba Aquilion). The diagnostic yield of CTA for >70%, 50–70%, and <50% stenoses was evaluated. The need for invasive angiography and revascularization was assessed during a mean follow-up of 22 months (range 9 to 27 months).
Results: Of the 228 patients evaluated, 43.9% were male, average age 59.3±10.3. Prior to CTA, 66.2% (n=151) had an equivocal functional test, while 33.8% (n=77) had no prior stress test. The diagnostic yield for any lesion was 62.7% (n=143), and similar for those with a prior equivocal stress testing and those without a prior stress test (58.2% vs. 72.7%, P=NS). Diagnostic yield for significant lesions (>50% stenosis) was high at 31% (n−71), and was also similar for those with and without a prior stress test (29.1% vs 35.0%, P=NS). Only patients with significant lesions on CTA (>50% stenosis) required revascularization during the follow-up period. (Table⇓). These results were similar in those with or without prior stress tests (12% vs 7.8%, P=0.34).
Conclusions: Among patients with and without prior equivocal stress tests, CTA detected a significant number of obstructive CAD lesions and effectively triaged for subsequent invasive angiography and revascularization. It appears to be a very promising diagnostic test in this population.