Department of Cardiovascular Surgery, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
Eur J Cardiothorac Surg. 2010 Aug;38(2):163-70. doi: 10.1016/j.ejcts.2010.01.029. Epub 2010 Jun 17.
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).
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.
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).
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.
本研究旨在评估缺血性心肌病（ICM）伴严重功能性二尖瓣反流（MR）患者行限制性二尖瓣环成形术（RMA）后，非梗死节段左心室（LV）容积、功能和局部心肌壁应力的变化。
22 例 ICM（射血分数<35%）伴严重 MR 患者在 RMA 前后 3 个月使用电影-血管造影多排 CT（cine-MDCT）进行检查。为了进行比较，还研究了 38 例正常对照者。cine-MDCT LV 图像在心动周期内重建，使用 Janz 法从 LV 收缩末期图像评估局部周向壁应力（收缩末期应力（ESS））。根据 AHA/ASE 标准，在心室的 6 个基底和 6 个中部 LV 节段确定 ESS。未分析 5 个心尖梗死节段。确定两个基底和中部 LV 区域的平均周向纤维缩短率（CFS）作为局部收缩性能的参数。
LV 舒张末期容积（指数）（LVEDVI）和 LV 收缩末期容积（指数）（LVESVI）显著下降，术后左心室射血分数（LVEF）增加。术后收缩末期和舒张末期球体指数均无显著变化。术后，基底和中部 LV 区域的局部 ESS 均显著下降。术后平均区域 ESS 值的变化与中部 LV 区域平均 CFS 增加幅度呈显著负相关（r=-0.67，p=0.0018）。中 LV 区域 ESS 的术后降低也与整体 EF 的改善相关（r=-0.72，p<0.01）。
本研究采用的 cine-MDCT 可能有助于评估 ICM 患者的局部心肌应力。我们发现，RMA 可以降低舒张末期和收缩末期容积，从而降低局部收缩期壁应力，导致功能性 MR 和 ICM 患者非梗死心肌的射血性能得到改善。
