(P192) DIAGNOSTIC ACCURACY OF IMAGING FOR CORONARY VASOMOTOR DYSFUNCTION IN ISCHEMIA WITH NO OBSTRUCTIVE CORONARY ARTERY DISEASE: A SYSTEMATIC REVIEW AND META-ANALYSIS

Background: Ischemia with no obstructive coronary artery disease (INOCA) is a heterogeneous clinical entity whose mechanisms are difficult to diagnose due to pathophysiology and diagnostic limitations. An underlying cause for the symptomatic manifestation within this population is thought to be coronary vasomotor dysfunction. Current reference standards to diagnose coronary vasomotor dysfunction involve the direct interrogation of coronary function through invasive testing. The utility of non-invasive modalities to diagnose coronary vasomotor dysfunction in the INOCA population has yet to be systematically reviewed. This review and meta-analysis aims to assess the diagnostic accuracy of invasive and non-invasive imaging modalities in identifying coronary vasomotor dysfunction and its endotypes in INOCA.

METHODS AND RESULTS: Ovid Medline, Ovid Embase, and The Cochrane Register of Controlled Trials were systematically searched, and bibliographies and Google Scholar were hand-searched. Studies were systematically screened by two independent reviewers. Pooled estimates of sensitivity and specificity were calculated using the bivariate random effects and hierarchal summary receiver operating characteristic models. Study quality was assessed using the QUADAS-2, heterogeneity was assessed using I2 and tau2, and publication bias was assessed using Deek’s test. Of the 1657 studies were identified, 34 (n=6210) studies were included in the systematic review, of which 32 (n=5294) had available diagnostic accuracy data which was included in the meta-analysis. The mean sample size for each study was 183 [95%CI 71, 294], of which a mean percentage of 64% [95%CI 16, 40] were female, and study subjects had a mean age of 59 years [95%CI 57, 60]. Pooled estimates of sensitivity and specificity across all endotypes were 74% (95%CI 67-81, I2=74, Tau2=0.76) and 78% (95%CI 69-85, I2=80, Tau2=1.28) for non-invasive modalities and 73% (95%CI 62-82, I2=81, Tau2=0.76) and 79% (95%CI 75-82, I2=40, Tau2=0.07) for invasive modalities. Pooled estimates varied based on the endotype diagnosed and modality used.

Conclusion: This study found comparable sensitivity and specificity between non-invasive and invasive imaging modalities, with variations between endotypes consistent with the heterogeneous pathophysiology of coronary vasomotor dysfunction. However, the substantial between-study heterogeneity necessitates further exploration before the adoption of non-invasive modalities for diagnosing coronary vasomotor dysfunction in clinical practice can be recommended.