News | June 18, 2009

Stress Imaging Best Noninvasive Diagnostic Test of In-stent Restenosis

June 18, 2009 - Researchers at the Heart and Vascular Institute and the Imaging Institute at the Cleveland Clinic in Ohio said stress imaging remains the most acceptable noninvasive technique for diagnosis of in-stent restenosis (ISR) based on a meta-analysis using available studies to determine the diagnostic efficacy of 64-slice computed tomography (CT) in evaluation of ISR.

The study is featured in this week’s issue of the American Journal of Cardiology (Vol. 103, Issues 12, pages 1,675-1,681, June 15, 2009).

Sixty-four–slice CT allows optimal noninvasive assessment of coronary artery disease. However, a variety of artifacts limit evaluation of stented coronary segments. Researchers pooled efficacy estimates across studies using random-effects models. They identified 14 studies, which included 895 patients (1,447 stents, mean diameter 3.1 mm). Of these, 1,231 (91.4 percent) stents were adequately assessed by 64-slice CT. Overall sensitivity was 91 percent (95 percent confidence interval [CI] 86 to 94), specificity was 91 percent (95 percent CI 89 to 92), positive predictive value (PPV) was 68 percent (95 percent CI 63 to 73), and negative predictive value (NPV) was 98 percent (95 percent CI 97 to 99). The summary receiver operating characteristic curves graph showed a symmetric area under the curve of 0.96.

When nonassessable segments were included, overall sensitivity and specificity decreased to 87 percent (95 percent CI 81 to 92) and 84 percent (95 percent CI 82 to 87), with a PPV of 53 percent (95 percent CI 47 to 59) and an NPV of 97 percent (95 percent CI 96 to 98), respectively. In conclusion, 64-slice CT detects (high sensitivity and specificity) or excludes ISR (high NPV) with a high degree of confidence; however, precise quantification of ISR is not accurate (low PPV). Efficacy estimates are even lower when nonassessable segments are included, researchers said.

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