title: Assessment of regional myocardial wall stress before and after surgical correction of functional ischaemic mitral regurgitation using multidetector computed tomography and novel software system.
abstract: OBJECTIVE
  The objective of this study was to assess changes in left ventricular (LV) volume, function and regional myocardial wall stress in non-infarcted segments following restrictive mitral annuloplasty (RMA) in patients with ischaemic cardiomyopathy (ICM) and severe functional mitral regurgitation (MR).
  
  
  METHODS
  Twenty-two patients with ICM (ejection fraction <35%) and severe MR were investigated before and 3 months after RMA using cine-angiographic multidetector row computed tomography (cine-MDCT). For comparative purposes, 38 normal subjects were also studied. Cine-MDCT LV images were reconstructed in a cardiac cycle and regional circumferential wall stress (end-systolic stress (ESS)) was evaluated from the LV end-systolic image using Janz's method. The ESS was determined in six basal and six mid-LV segments of the ventricle based on AHA/ASE criteria. Five apical infarcted segments were not analysed. Mean circumferential fibre shortening (CFS) in both basal and mid-LV regions was determined as a parameter of regional systolic performance.
  
  
  RESULTS
  Left ventricular end-diastolic volume (index) (LVEDVI) and left ventricular end-systolic volume (index) (LVESVI) decreased significantly and left ventricular ejection fraction (LVEF) increased after surgery. Neither end-systolic nor end-diastolic sphericity index changed significantly after surgery. Regional ESS significantly decreased in both basal and mid-LV regions after surgery. There was a significant inverse correlation between the change in average value of regional ESS and magnitude of increase in mean CFS of the mid-LV region (r=-0.67, p=0.0018). Postoperative reduction in ESS in the mid-LV region was also correlated with improvement in global EF (r=-0.72, p<0.01).
  
  
  CONCLUSIONS
  The present cine-MDCT may be useful for assessing regional myocardial stress in patients with ICM. We found that RMA could reduce both end-diastolic and end-systolic volume leading to reduction in regional systolic wall stress, which resulted in improved ejection performance of non-infarcted myocardium in patients with functional MR and ICM.
authors.affiliation: Department of Cardiovascular Surgery, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Shudo
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Taniguchi
authors.forename: Koji
authors.initials: K
authors.lastname: Takeda
authors.forename: Taichi
authors.initials: T
authors.lastname: Sakaguchi
authors.forename: Hajime
authors.initials: H
authors.lastname: Matsue
authors.forename: Hironori
authors.initials: H
authors.lastname: Izutani
authors.forename: Goro
authors.initials: G
authors.lastname: Matsumiya
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Sawa
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure / Q000502:physiology; D009202:Cardiomyopathies / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D002932:Cineangiography / Q000379:methods; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D058386:Mitral Valve Annuloplasty / Q000379:methods; D008944:Mitral Valve Insufficiency / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D011184:Postoperative Period; D012984:Software; D013314:Stress, Mechanical; D013318:Stroke Volume / Q000502:physiology; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000502:physiology; D020257:Ventricular Remodeling / Q000502:physiology