Faculty of Medicine, University of Geneva, Department of Anaesthesiology, University Hospital, CH-1211 Geneva 14, Switzerland.
Crit Care. 2010;14(3):R101. doi: 10.1186/cc9040. Epub 2010 Jun 3.
Left ventricular (LV) dysfunction frequently occurs after cardiac surgery, requiring inotropic treatment and/or mechanical circulatory support. In this study, we aimed to identify clinical, surgical and echocardiographic factors that are associated with LV dysfunction during weaning from cardiopulmonary bypass (CPB) in high-risk patients undergoing valve replacement for aortic stenosis.
Perioperative data were prospectively collected in 108 surgical candidates with an expected operative mortality >or=9%. All anesthetic and surgical techniques were standardized. Reduced LV systolic function was defined by an ejection fraction <40%. Diastolic function of the LV was assessed using standard Doppler-derived parameters, tissue Doppler Imaging (TDI) and transmitral flow propagation velocity (Vp).
Doppler-derived pulmonary flow indices and TDI could not be obtained in 14 patients. In the remaining 94 patients, poor systolic LV was documented in 14% (n = 12) and diastolic dysfunction in 84% of patients (n = 89), all of whom had Vp <50 cm/s. During weaning from CPB, 38 patients (40%) required inotropic and/or mechanical circulatory support. By multivariate regression analysis, we identified three independent predictors of LV systolic dysfunction: age (Odds ratio [OR] = 1.11; 95% confidence interval (CI), 1.01 to 1.22), aortic clamping time (OR = 1.04; 95% CI, 1.00 to 1.08) and Vp (OR = 0.65; 95% CI, 0.52 to 0.81). Among echocardiographic measurements, Vp was found to be superior in terms of prognostic value and reliability. The best cut-off value for Vp to predict LV dysfunction was 40 cm/s (sensitivity of 72% and specificity 94%). Patients who experienced LV dysfunction presented higher in-hospital mortality (18.4% vs. 3.6% in patients without LV dysfunction, P = 0.044) and an increased incidence of serious cardiac events (81.6 vs. 28.6%, P < 0.001).
This study provides the first evidence that, besides advanced age and prolonged myocardial ischemic time, LV diastolic dysfunction characterized by Vp <or= 40 cm/sec identifies patients who will require cardiovascular support following valve replacement for aortic stenosis.
左心室（LV）功能障碍在心脏手术后经常发生，需要正性肌力治疗和/或机械循环支持。在这项研究中，我们旨在确定与高危主动脉瓣狭窄患者在体外循环（CPB）脱机期间左心室功能障碍相关的临床、手术和超声心动图因素。
前瞻性收集了 108 例预计手术死亡率≥9%的手术候选者的围手术期数据。所有麻醉和手术技术均标准化。LV 收缩功能降低定义为射血分数<40%。使用标准多普勒衍生参数、组织多普勒成像（TDI）和经二尖瓣血流传播速度（Vp）评估 LV 舒张功能。
14 例患者无法获得多普勒衍生的肺血流指数和 TDI。在其余 94 例患者中，14%（n=12）记录到左心室收缩功能不良，84%（n=89）患者存在舒张功能障碍，所有患者的 Vp<50cm/s。在 CPB 脱机期间，38 例患者（40%）需要正性肌力和/或机械循环支持。通过多变量回归分析，我们确定了左心室收缩功能障碍的三个独立预测因素：年龄（优势比[OR] = 1.11；95%置信区间[CI]，1.01 至 1.22）、主动脉夹闭时间（OR = 1.04；95%CI，1.00 至 1.08）和 Vp（OR = 0.65；95%CI，0.52 至 0.81）。在超声心动图测量中，Vp 在预后价值和可靠性方面表现更好。预测 LV 功能障碍的最佳 Vp 截断值为 40cm/s（敏感性为 72%，特异性为 94%）。发生 LV 功能障碍的患者院内死亡率较高（18.4%与无 LV 功能障碍患者的 3.6%，P=0.044），严重心脏事件发生率也较高（81.6%与 28.6%，P<0.001）。
这项研究首次提供证据表明，除了高龄和心肌缺血时间延长外，以 Vp<或=40cm/sec 为特征的 LV 舒张功能障碍可确定主动脉瓣狭窄患者在换瓣后需要心血管支持。
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