Multivessel Coronary Artery Disease Presented With Normal Myocardial Perfusion Scan: The Significance of a High Transient Ischemic Dilation

摘要

Transient ischemic dilation (TID) is significantly correlated with stress-induced diffuse subendocardial hypoperfusion, and produces a visually larger left ventricular cavity. A high TID ratio is indicative of severe and extensive multi-vessel coronary artery disease (CAD) and high risk of cardiac events, even in acquisitions with normal perfusion. We report a case of a 65-year-old female with a long history of diabetes mellitus, hypertension, and hyperlipidemia, who had a non-ST elevation myocardial infarction in 2009 and underwent stent deployment for right coronary artery (RCA) disease. About 1 month ago, the patient had a sudden onset of dyspnea and retrosternal chest pressure while mopping that persisted for 30 min with a partial response to nitroglycerin. Myocardial perfusion study showed homogeneous distribution of radiotracer (thallium chloride) in stress and rest tests at all myocardial walls. However, a high TID ratio (1.58) was noted. Coronary angiogram revealed 90% proximal left anterior descending artery (LAD) stenosis, proximal RCA 50% in-stent restenosis, middle RCA 70% in-stent restenosis, and distal RCA 70% stenosis. Stenting of the LAD and distal RCA, and balloon dilatation of the RCA in-stent restenosis was performed. In this case with hypertension, diabetes, hyperlipidemia and a previous history of CAD, the TID ratio provides incremental diagnostic value for the identification of severe and extensive CAD.