Impaired Subendocardial Wall Thickening and Post-Systolic Shortening Are Signs of Critical Myocardial Ischemia in Patients With Flow-Limiting Coronary Stenosis

• Published in: Circulation Journal Vol. 75; no. 8; pp. 1934 - 1941
• Main Authors: Shiotsuka, Junji, Aonuma, Kazutaka, Machino, Tomoko, Baba, Masako, Ishizu, Tomoko, Seo, Yoshihiro, Higuchi, Haruhiko, Noguchi, Yuichi
• Format: Journal Article
• Language: English
• Published: Japan The Japanese Circulation Society 2011
• Subjects: Aged; Coronary Stenosis - diagnostic imaging; Coronary Stenosis - pathology; Coronary Stenosis - physiopathology; Echocardiography; Female; Heart Ventricles - diagnostic imaging; Heart Ventricles - pathology; Heart Ventricles - physiopathology; Humans; Ischemic heart disease; Male; Middle Aged; Myocardial Contraction; Myocardium - pathology; Post-systolic shortening; Transmural strain heterogeneity
• ISSN: 1346-9843; 1347-4820; 1347-4820
• DOI: 10.1253/circj.CJ-10-1085

Background: The early diagnosis of myocardial ischemia is still challenging. The aim of the present study was to determine whether subendocardial hypokinesis and post-systolic contraction could be early markers of myocardial ischemia. Methods and Results: Thirty-one consecutive patients with flow-limiting severe coronary stenosis but without visually abnormal left ventricular wall motion underwent quantitative echocardiography. Myocardial strain was measured using layer-by-layer analysis in severely hypoperfused segments. Radial strain (RS) was measured in the subendocardial, subepicardial, and total wall (innerRS, outerRS, and totalRS, respectively). Circumferential strain (CS) was also measured as 3 separate layers: subendocardial, mid-layer, and subepicardial layers (innerCS, midCS, and outerCS, respectively). Post-systolic shortening (PSS) was defined as the peak strain after end systole, and post-systolic strain index (PSI) was calculated as PSS divided by end-systolic strain. TotalRS was similar between ischemic and normally perfused segments, but innerRS and inner/outer RS ratio were significantly smaller in the ischemic segments than in corresponding segments in healthy subjects. Receiver operating characteristic analysis identified an optimum cut-off for PSI of 0.6. The combined criteria of inner/outer RS ratio <1.0 and PSI >0.6 achieved 95% specificity for the presence of flow-limiting stenosis. Conclusions: Combined assessment of both subendocardial contractile impairment and PSS is very useful in identifying a severely hypoperfused left ventricular wall even without visual wall motion abnormality. (Circ J 2011; 75: 1934-1941)