Coronary artery disease
Usefulness of Multislice Computed Tomographic Coronary Angiography to Identify Patients With Abnormal Myocardial Perfusion Stress in Whom Diagnostic Catheterization May Be Safely Avoided

https://doi.org/10.1016/j.amjcard.2007.06.069Get rights and content

Computed tomographic angiography (CTA) has been validated for noninvasive assessment of coronary anatomy. The aim was to establish whether CTA could guide the use of invasive coronary angiography (ICA) in symptomatic patients with intermediate risk after myocardial perfusion stress imaging (MPSI). From April 2005 to February 2006, patients referred for CTA to a cardiology practice were entered into a database. Inclusion required symptoms suggestive of coronary artery disease and intermediate-risk MPSI. Subjects with intermediate risk after MPSI underwent CTA, and if severe stenosis or moderate stenosis matching a perfusion defect was found, ICA was performed. If appropriate, patients were then sent for revascularization. Clinical follow-up was completed until December 2006. Main outcome measures were number of patients sent for ICA, immediate revascularization after ICA, and adverse outcomes (death, myocardial infarction, and late revascularization). Four hundred twenty-one patients were included. Adequate diagnostic-quality images were obtained in 99%. After MPSI-CTA assessment, 78 patients (18.5%) were sent for ICA and 343 (81.5%) were medically managed. Follow-up was 15 ± 3 months. In the group referred for ICA, there were 50 cases of immediate revascularization, 1 non–ST-segment elevation myocardial infarction, 1 death, and 5 patients requiring repeat ICA, 3 of whom underwent late revascularization. In the medically managed group, 6 patients required late ICA, 1 of whom underwent revascularization. In conclusion, in symptomatic patients with suspected coronary artery disease and intermediate-risk MPSI results, CTA can identify up to 80% of patients at low risk of events in whom ICA may be safely avoided. Additional studies assessing new technologies combining MPSI-CTA are needed to refine imaging strategies in these patients.

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Methods

From April 2005 to February 2006, all patients referred for CTA at a single-specialty ambulatory cardiology practice were prospectively entered into a database based on a predefined comprehensive data-collection tool after informed consent was obtained. As 1 of the indications for CTA, any of the 25 cardiologists in the group would refer symptomatic patients in the absence of contraindications if they had a previous abnormal MPSI result based on the criteria7, 8, 9 of (1) stress-induced

Results

Of 2,132 patients who underwent MPSI during the study period, 421 (20%) were referred for CTA because of being classified as intermediate risk after MPSI. Baseline characteristics, previous symptoms, and type and results of previous stress testing are listed in Table 1.

Average heart rate achieved before the procedure was 56 ± 13 beats/min. Adequate diagnostic quality was achieved in 99% of cases, with all 17 AHA segments available in 92%. Most uninterpretable segments were distal or in small

Discussion

This study showed that CTA could significantly impact on the clinical evaluation of symptomatic patients classified at intermediate risk for cardiovascular events after MPSI. Recent reports emphasized the strengths of the complementary information provided by combined MPSI-CTA evaluation; however, to our knowledge, this was the first study to show its application in clinical practice.12

The goal of assessing patients with known or suspected CAD was to identify those in whom subsequent

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This work was supported by Chicagoland Heart Foundation, Hinsdale, Illinois.

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