title: Impaired subendocardial wall thickening and post-systolic shortening are signs of critical myocardial ischemia in patients with flow-limiting coronary stenosis.
abstract: 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.
  
  
  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.
authors.affiliation: Cardiovascular Division, Institute of Clinical Medicine, University of Tsukuba, Japan. tomoco@md.tsukuba.ac.jp
authors.forename: Tomoko
authors.initials: T
authors.lastname: Ishizu
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Seo
authors.forename: Masako
authors.initials: M
authors.lastname: Baba
authors.forename: Tomoko
authors.initials: T
authors.lastname: Machino
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Higuchi
authors.forename: Junji
authors.initials: J
authors.lastname: Shiotsuka
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Noguchi
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Aonuma
mesh_terms: D000368:Aged; D023921:Coronary Stenosis / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D004452:Echocardiography; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D009206:Myocardium / Q000473:pathology*