Department of Surgery, Columbia Presbyterian Medical Center, New York, New York 10032, USA.
Ann Thorac Surg. 2013 Sep;96(3):808-15. doi: 10.1016/j.athoracsur.2013.04.101. Epub 2013 Jul 16.
This study sought to determine whether optimized biventricular pacing increases cardiac index in patients at risk of left ventricular dysfunction after cardiopulmonary bypass. Procedures included coronary artery bypass, aortic or mitral surgery and combinations. This trial was approved by the Columbia University Institutional Review Board and was conducted under an Investigational Device Exemption.
Screening of 6,346 patients yielded 47 endpoints. With informed consent, 61 patients were randomized to pacing or control groups. Atrioventricular and interventricular delays were optimized 1 (phase I), 2 (phase II), and 12 to 24 hours (phase III) after bypass in all patients. Cardiac index was measured by thermal dilution in triplicate. A 2-sample t test assessed differences between groups and subgroups.
Cardiac index was 12% higher (2.83±0.16 [standard error of the mean] vs 2.52±0.13 liters/minute/square meter) in the paced group, less than predicted and not statistically significant (p=0.14). However, when aortic and aortic-mitral surgery groups were combined, cardiac index increased 29% in the paced group (2.90±0.19, n=14) versus controls (2.24±0.15, n=11) (p=0.0138). Using a linear mixed effects model, t-test revealed that mean arterial pressure increased with pacing versus no pacing at all optimization points (phase I 79.2±1.7 vs 74.5±1.6 mm Hg, p=0.008; phase II 75.9±1.5 vs 73.6±1.8, p=0.006; phase III 81.9±2.8 vs 79.5±2.7, p=0.002).
Cardiac index did not increase significantly overall but increased 29% after aortic valve surgery. Mean arterial pressure increased with pacing at 3 time points. Additional studies are needed to distinguish rate from resynchronization effects, emphasize atrioventricular delay optimization, and examine clinical benefits of temporary postoperative pacing.
本研究旨在确定优化的双心室起搏是否会增加体外循环后左心室功能障碍风险患者的心输出量。手术包括冠状动脉旁路移植术、主动脉瓣或二尖瓣手术以及联合手术。该试验已获得哥伦比亚大学机构审查委员会的批准，并在一项研究性器械豁免下进行。
对 6346 例患者进行筛查，得到 47 个终点。在获得知情同意的情况下，61 例患者被随机分配到起搏组或对照组。在所有患者中，在体外循环后 1 小时（I 期）、2 小时（II 期）和 12-24 小时（III 期）优化房室和室间延迟。通过热稀释法重复测量心输出量。采用两样本 t 检验评估组间和亚组间的差异。
起搏组心输出量增加 12%（2.83±0.16[均数标准差] vs 2.52±0.13 升/分钟/平方米），但低于预期，无统计学意义（p=0.14）。然而，当主动脉瓣和主动脉瓣二尖瓣手术组合并时，起搏组心输出量增加 29%（2.90±0.19，n=14），而对照组为 22%（2.24±0.15，n=11）（p=0.0138）。使用线性混合效应模型，t 检验显示，在所有优化点（I 期 79.2±1.7 对 74.5±1.6 mmHg，p=0.008；II 期 75.9±1.5 对 73.6±1.8，p=0.006；III 期 81.9±2.8 对 79.5±2.7，p=0.002），与无起搏相比，平均动脉压随起搏而升高。
总体上心输出量无显著增加，但主动脉瓣手术后增加 29%。平均动脉压在 3 个时间点随起搏而升高。需要进一步研究以区分速率与再同步化效应，强调房室延迟优化，并研究临时术后起搏的临床获益。
