Kainuma Satoshi, Taniguchi Kazuhiro, Toda Koichi, Shudo Yasuhiro, Takeda Koji, Funatsu Toshihiro, Miyagawa Shigeru, Kondoh Haruhiko, Nishi Hiroyuki, Yoshikawa Yasushi, Fukushima Satsuki, Hamada Seiki, Kubo Koji, Daimon Takashi, Sawa Yoshiki
Department of Cardiovascular Surgery, Japan Labor Health and Welfare Organization Osaka Rosai Hospital, Sakai, Osaka, Japan; Department of Cardiovascular Surgery, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
Department of Cardiovascular Surgery, Japan Labor Health and Welfare Organization Osaka Rosai Hospital, Sakai, Osaka, Japan.
J Cardiol. 2015 Oct;66(4):279-85. doi: 10.1016/j.jjcc.2015.02.015. Epub 2015 Apr 4.
Restrictive mitral annuloplasty (RMA) can reverse left ventricular (LV) remodeling and reduce plasma B-type natriuretic peptide (BNP), a surrogate biomarker of heart failure. However, the relationship between reverse LV remodeling and plasma BNP changes after RMA is poorly defined. We explored the main hemodynamic factors contributing to change in plasma BNP after RMA in patients with functional mitral regurgitation (MR).
Twenty-four patients with moderate to severe functional MR secondary to LV systolic dysfunction [ejection fraction (EF) <40%] underwent 64-row multidetector computed tomography (MDCT) before and 1.4 months after RMA. LV end-diastolic volume index (EDVI), end-systolic volume index (ESVI), LVEF, and regional and global end-systolic wall stress (ESS) were calculated from 3-dimensional MDCT images, with blood samples for plasma BNP measurement collected the same day.
After RMA, LV volumes and global ESS were decreased, while LVEF improved (all p<0.01). There were significant correlations between changes in LVEDVI and LVESVI (r=0.90, p<0.0001), LVESVI and global ESS (r=0.54, p=0.006), and global ESS and LVEF (r=-0.60, p=0.002). The median value for the plasma BNP also decreased from 597 pg/ml [interquartile range (IQR), 360-934 pg/ml] to 207 pg/ml (IQR, 124-271 pg/ml), in association with changes in LVEDVI (r=0.47, p=0.019), LVESVI (r=0.56, p=0.004), LVEF (r=-0.60, p=0.002), and global ESS (r=0.74, p<0.0001). Multivariate regression analysis showed that global ESS change was the strongest contributor to change in natural-log-transformed plasma BNP (standardized partial regression coefficient=0.59, p=0.004), indicating a strong association between decrease in LV afterload and reduction in plasma BNP level after RMA.
There may be a significant association between LV reverse remodeling and plasma BNP change after RMA. Furthermore, LV end-systolic myocardial stress may be the key mechanical stimulus influencing plasma BNP after surgical correction for functional MR. Whether these favorable BNP responses and reverse remodeling can predict improved survival requires further study.
限制性二尖瓣环成形术（RMA）可逆转左心室（LV）重构并降低血浆B型利钠肽（BNP），后者是心力衰竭的替代生物标志物。然而，RMA后左心室逆向重构与血浆BNP变化之间的关系尚不明确。我们探讨了功能性二尖瓣反流（MR）患者RMA后导致血浆BNP变化的主要血流动力学因素。
24例继发于左心室收缩功能障碍[射血分数（EF）<40%]的中重度功能性MR患者在RMA前及术后1.4个月接受了64排多层螺旋计算机断层扫描（MDCT）检查。从三维MDCT图像计算左心室舒张末期容积指数（EDVI）、收缩末期容积指数（ESVI）、左心室射血分数（LVEF）以及区域和整体收缩末期壁应力（ESS），并于同日采集血样测量血浆BNP。
RMA后，左心室容积和整体ESS降低，而LVEF改善（均p<0.01）。左心室舒张末期容积指数（LVEDVI）与收缩末期容积指数（LVESVI）的变化之间（r=0.90，p<0.0001）、LVESVI与整体ESS之间（r=0.54，p=0.006）以及整体ESS与LVEF之间（r=-0.60，p=0.002）存在显著相关性。血浆BNP的中位数也从597 pg/ml[四分位间距（IQR），360-93 pg/ml]降至207 pg/ml（IQR，124-271 pg/ml），与LVEDVI（r=0.47，p=0.019）、LVESVI（r=0.56，p=0.004）、LVEF（r=-0.60，p=0.002）和整体ESS（r=0.74，p<0.0001）的变化相关。多变量回归分析显示，整体ESS变化是自然对数转换后的血浆BNP变化的最强贡献因素（标准化偏回归系数=0.59，p=0.004），表明左心室后负荷降低与RMA后血浆BNP水平降低之间存在密切关联。
RMA后左心室逆向重构与血浆BNP变化之间可能存在显著关联。此外，左心室收缩末期心肌应力可能是功能性MR手术矫正后影响血浆BNP的关键机械刺激因素。这些有利的BNP反应和逆向重构是否能预测生存率提高尚需进一步研究。
