Division of Cardiac Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
J Thorac Cardiovasc Surg. 2013 Mar;145(3):824-31. doi: 10.1016/j.jtcvs.2012.05.018. Epub 2012 Jun 12.
The effects of ventricular restraint level on left ventricular reverse remodeling are not known. We hypothesized that restraint level affects the degree of reverse remodeling and that restraint applied in an adjustable manner is superior to standard, nonadjustable restraint.
This study was performed in 2 parts using a model of chronic heart failure in the sheep. In part I, restraint was applied at control (0 mm Hg, n = 3), low (1.5 mm Hg, n = 3), and high (3.0 mm Hg, n = 3) levels with an adjustable and measurable ventricular restraint (AMVR) device. Restraint level was not altered throughout the 2-month treatment period. Serial restraint level measurements and transthoracic echocardiography were performed. In part II, restraint was applied with the AMVR device set at 3.0 mm Hg (n = 6) and adjusted periodically to maintain that level. This was compared with restraint applied in a standard, nonadjustable manner using a mesh wrap (n = 6). All subjects were followed up for 2 months with serial magnetic resonance imaging.
In part I, there was greater and earlier reverse remodeling in the high restraint group. In both groups, the rate of reverse remodeling peaked and then declined as the measured restraint level decreased with progression of reverse remodeling. In part II, adjustable restraint resulted in greater reverse remodeling than standard restraint. Left ventricular end diastolic volume decreased by 12.7% (P = .005) with adjustable restraint and by 5.7% (P = .032) with standard restraint. Left ventricular ejection fraction increased by 18.9% (P = .014) and 14.4% (P < .001) with adjustable and standard restraint, respectively.
Restraint level affects the rate and degree of reverse remodeling and is an important determinant of therapy efficacy. Adjustable restraint is more effective than nonadjustable restraint in promoting reverse remodeling.
心室约束水平对左心室逆重构的影响尚不清楚。我们假设约束水平会影响逆重构的程度，并且可调节方式的约束优于标准的、不可调节的约束。
本研究分两部分在绵羊慢性心力衰竭模型中进行。在第一部分中，使用可调节和可测量的心室约束（AMVR）装置，在对照（0mmHg，n=3）、低（1.5mmHg，n=3）和高（3.0mmHg，n=3）三个水平下施加约束。在整个 2 个月的治疗期间，约束水平未改变。进行了连续的约束水平测量和经胸超声心动图检查。在第二部分中，使用 AMVR 装置在 3.0mmHg 水平下施加约束（n=6），并定期调整以维持该水平，并与使用网套以标准、不可调节方式施加的约束（n=6）进行比较。所有患者均接受了 2 个月的随访，并行系列磁共振成像检查。
在第一部分中，高约束组的逆重构程度更大且更早。在两组中，随着逆重构的进展，测量的约束水平降低，逆重构的速度达到峰值，然后下降。在第二部分中，可调节约束比标准约束导致更大的逆重构。可调约束使左心室舒张末期容积减少 12.7%（P=0.005），标准约束减少 5.7%（P=0.032）。左心室射血分数分别增加了 18.9%（P=0.014）和 14.4%（P<0.001），可调约束和标准约束分别增加了 18.9%和 14.4%。
约束水平会影响逆重构的速度和程度，是治疗效果的重要决定因素。可调节约束比不可调节约束更能有效促进逆重构。
