心室驱动改善小型衰竭心脏的收缩和舒张心肌功能。

Department of Surgery, Wright State University School of Medicine, Dayton, Ohio 45409, USA.

Ann Thorac Surg. 2009 Dec;88(6):1982-8; discussion 1988. doi: 10.1016/j.athoracsur.2009.08.048.

BACKGROUND

Direct mechanical ventricular actuation (DMVA) provides non-blood contacting augmentation of ventricular function. The device has promise for supporting the pediatric heart. The purpose of this study was to assess DMVA's effect in a small animal model of heart failure.

METHODS

Anesthetized rabbits (n = 6) underwent sternotomy and were instrumented for hemodynamic monitoring. A 10-MHz ultrasound probe was used for transesophageal echocardiography imaging. Heart failure (cardiac output <50% baseline) was induced with esmolol. Phenylephrine was titrated to maintain baseline mean arterial pressure. Transesophageal echocardiography imaging was acquired at baseline, heart failure, and subsequent DMVA support for 2 hours. Image analysis was used to derive ejection fraction, cardiac output, and stroke work as measures of left ventricular function. Speckle tracking software was used to derive myocardial strain rates as load-independent measures of left ventricular myocardial function.

RESULTS

Mean ejection fraction was significantly increased during DMVA support (0.585 +/- 0.035) versus failure (0.215 +/- 0.014; p < 0.001). Peak global left ventricular systolic and diastolic strain rates (1/second) were significantly increased during DMVA (-2.85 +/- 0.33 and 2.92 +/- 0.37) versus failure (-1.69 +/- 0.11 and 1.99 +/- 0.14; p < 0.001 and 0.004, respectively). Peak strain rates during DMVA in the failing heart were similar to baseline.

CONCLUSIONS

Direct mechanical ventricular actuation augments both systolic and diastolic left ventricular pump function. Diastolic augmentation distinguishes the device from other direct cardiac compression methods. This study demonstrated that DMVA in the small-sized, failing heart improves both systolic and diastolic myocardial function, which has favorable implications for left ventricular recovery. Direct mechanical ventricular actuation's salutary effects can be provided to the failing pediatric heart without complications of blood contact.

背景

直接机械心室驱动（DMVA）提供非血液接触的心室功能增强。该设备有望为小儿心脏提供支持。本研究的目的是在心力衰竭的小动物模型中评估 DMVA 的效果。

方法

麻醉兔（n=6）行胸骨切开术，并进行血流动力学监测。使用 10MHz 超声探头进行经食管超声心动图成像。用艾司洛尔诱导心力衰竭（心输出量<基线的 50%）。用苯肾上腺素滴定以维持基线平均动脉压。在基线、心力衰竭和随后的 DMVA 支持 2 小时时获取经食管超声心动图图像。图像分析用于得出射血分数、心输出量和每搏功作为左心室功能的测量值。斑点追踪软件用于得出心肌应变率作为左心室心肌功能的无负荷测量值。

结果

DMVA 支持时平均射血分数显著增加（0.585±0.035），而心力衰竭时为（0.215±0.014；p<0.001）。DMVA 时左心室整体收缩和舒张应变率峰值（1/秒）显著增加（-2.85±0.33 和 2.92±0.37），而心力衰竭时为（-1.69±0.11 和 1.99±0.14；p<0.001 和 0.004）。在心力衰竭的情况下，DMVA 时的峰值应变率与基线相似。