核素心肌显像指导左心室导线植入提高心脏再同步治疗疗效的临床研究：基本原理和设计方案

Single photon emission computed tomography myocardial perfusion imaging guided left ventricular lead implantation to improve the response to cardiac resynchronization therapy： rationale and design

背景心脏再同步治疗（CRT）已经成为部分慢性心力衰竭（心衰）患者的有效治疗手段。然而，有30％左右的CRT患者术后无反应，同时左心室导线的植入部位被认为是与CRT无反应相关的重要因素。多数相关研究表明左心室导线植入最迟机械激动且避免瘢痕的节段可以显著提升CRT的疗效。核素心肌灌注显像相位分析技术作为全新的检测方法，可以准确评估左心室机械失同步、最迟激动部位以及瘢痕负荷，从而定位CRT左心室导线最优植入节段，但是目前国内外缺乏通过核素指导左心室导线植入以提高CRT疗效的前瞻性，随机、对照研究（GUIDE—CRT）。基本原理GUIDE—CRT研究通过术前核素心肌灌注显像相位分析技术，评估左心室机械收缩同步性和瘢痕符合及分布情况，定位最迟收缩且无瘢痕的节段为最优起搏节段，探讨核素心肌显像技术指导左心室导线植入对于提高CRT疗效的可行性及有效性。设计方案全国19家中心共同参与本研究，入选的CRT患者随机分为核素指导组和对照组。术前采集基线超声心动图数据以及通过核素心肌灌注显像相位分析明确左心室导线最优植入节段。对于核素指导组患者，手术者在相位分析结果的指导下试图将左心室导线植入最迟激动且非瘢痕的节段或其临近节段。对照组则按照常规CRT手术流程放置左心室导线。所有病例依据6个月超声心动图指标随访评估CRT疗效。主要终点是左心室收缩末期容积（LVESV）的变化值。次要终点包括左心室舒张末期容积（LVEDV）下降值，左心室射血分数（LVEF）改变值以及CRT反应率，CRT有反应定义为6个月随访LVESV下降较基线超过15％。结论核素指导左心室导线植入比常规植入可显著提高CRT的疗效。

Background Cardiac resynchronization therapy （ CRT ）is an effective treatment for chronic heart failure patients.However, approximately 30% of recipients exhibit no response to CRT and the position of left ventricular （ LV ） lead is thought to be an important factor associated with no response. Majority of the related studies indicated that implantation of LV leads at the sites of the latest activation and away from scar can significantly improve the response to CRT. Single photon emission computed tomography （ SPECT ） myocardial perfusion imaging （ MPI ） phase analysis （ PA ） is a novel method to assess LV mechanical dyssynchrony, the site of the latest activation and scar burden to recommend the suitable position for LV lead. Therefore, randomized, controlled trials using SPECT to guide LV lead implantation to improve CRT response is needed. Rationale GUIDE-CRT study applies pre-operation SPECT MPI AP to evaluate LV mechanical dyssynchrony and distribution of scar and identify the site of the latest activation segment away from scar as optimal pacing site. The feasibility and effectiveness of SPECT MPI PA in guiding LV lead implantation to improve CRT response will be verified. Design Patients with standard CRT indications will be enrolled in 19 centers in China and randomized to two groups （ Guided vs.Control ）. All the patients will undergo baseline echocardiographic assessment, and SPECT imaging to identify the optimal LV lead positions from 13 LV segments. In the Guided group, the implanters will receive SPECT imaging guidance and attempt to place the LV leads to the target positions define as the LV lead is at or close to the latest activation segment away from scar. In the Control group, the patients will undergo routine LV lead implantation. All patients receive 6-month follow-up echocardiographic assessment to evaluate CRT response. The primary endpoint is reduction of LV end-systolic volume （ LVESV ）. The secondary endpoints include reduction of LV end-diastolic volume, changes of LV ejection fraction, and CRT response rate defined as a relative decrease of LVESV by ≥ 15% from baseline to 6-month follow-up. Conclusion SPECT guided LV lead implantation will obviously improve CRT efficacy.