Abstract
BackgroundTransient ischemic dilatation (TID) of the left ventricle is a potential marker of high risk obstructive coronary artery disease on stress myocardial perfusion imaging (MPI). There is, however, interstudy variation in the diagnostic performance of TID for identification of severe and extensive coronary disease anatomy, and varied prognostic implications in the published literature. MethodsWe searched MEDLINE, EMBASE, and COCHRANE databases for studies where TID was compared with invasive or CT coronary angiography for evaluation of coronary artery stenosis. Two reviewers independently evaluated and abstracted data from each study. A bivariate random effects model was used to derive pooled sensitivities and specificities, in order to account for correlation between TID in MPI and anatomic disease severity. ResultsA total of 525 articles were reviewed, of which 51 met inclusion criteria. Thirty-one studies contributed to the analysis, representing a total of 2037 patients in the diagnostic meta-analysis and 9003 patients in the review of prognosis. The ratio above which TID was deemed present ranged from 1.13 to 1.38. Pooled sensitivity was 44% (95% CI 30%-60%) and specificity was 88% (95% CI 83%-92%) for the detection of extensive or severe anatomic coronary artery disease. Analysis of outcome data demonstrated increased cardiac event rates in patients with TID and an abnormal MPI. In otherwise normal perfusion, TID is an indicator of poor prognosis in patients with diabetes and/or a history of coronary disease. ConclusionsAmong patients undergoing MPI, the presence of TID is specific for the detection of extensive or severe coronary artery disease.
Highlights
Myocardial perfusion Imaging (MPI) is an established tool for the diagnosis and risk stratification of patients with coronary artery disease (CAD) for over three decades.[1]
We excluded studies where: a) there was no coronary arterial anatomic assessment for comparison, or b) there was no clear documentation of the method used to calculate the ratio above which transient ischemic dilation (TID) was diagnosed
Of the remaining 51 articles, 20 studies were excluded because: (a) there was no evaluation of coronary anatomy for diagnostic studies [n = 11], (b) they included only patients with left ventricular dysfunction and fixed perfusion defects for prognostic studies [n = 1], (c) there was no clear documentation of the method used to calculate the ratio above which TID was diagnosed or only visual assessment of TID was employed [n = 5], (d) incomplete data [n = 2], and (e) duplicate data [n = 1] as shown in Figure 1 (Group Z)
Summary
Myocardial perfusion Imaging (MPI) is an established tool for the diagnosis and risk stratification of patients with coronary artery disease (CAD) for over three decades.[1]. The pathophysiology of ischemic LV dilatation remains unclear with the theory of subendocardial ischemia gaining the widest acceptance.[4,5] Others cite data supporting ischemia induced physical LV dilation post stress.[6,7] several studies have demonstrated that ischemic LV dilatation may be present in patients with normal perfusion and no significant epicardial coronary disease; for example in patients with hypertrophic cardiomyopathy,[8] or in patients with hypertensive heart disease and left ventricular hypertrophy.[9] the true diagnostic accuracy of TID on MPI is debated and the optimal threshold for its definition remains undefined. There is, interstudy variation in the diagnostic performance of TID for identification of severe and extensive coronary disease anatomy, and varied prognostic implications in the published literature
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