Assessment of regional myocardial wall stress before and after surgical correction of functional ischaemic mitral regurgitation using multidetector computed tomography and novel software system.
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.
Shudo
Yasuhiro
Y
Department of Cardiovascular Surgery, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
Taniguchi
Kazuhiro
K
Takeda
Koji
K
Sakaguchi
Taichi
T
Matsue
Hajime
H
Izutani
Hironori
H
Matsumiya
Goro
G
Sawa
Yoshiki
Y
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