Predictors of Total Mortality and Echocardiographic Response for Cardiac Resynchronization Therapy: A Cohort Study

Abstract Background: Clinical studies demonstrate that up to 40% of patients do not respond to cardiac resynchronization therapy (CRT), thus, appropriate patient selection is critical to the success of CRT in heart failure. Objective: Evaluation of mortality predictors and response to CRT in the Brazilian scenario. Methods: Retrospective cohort study including patients submitted to CRT in a tertiary hospital in southern Brazil from 2008 to 2014. Survival was assessed through a database of the State Department of Health (RS). Predictors of echocardiographic response were evaluated using Poisson regression. Survival analysis was performed by Cox regression and Kaplan Meyer curves. A two-tailed p value less than 0.05 was considered statistically significant. Results: A total of 170 patients with an average follow-up of 1011 ± 632 days were included. The total mortality was 30%. The independent predictors of mortality were age (hazard ratio [HR] of 1.05, p = 0.027), previous acute myocardial infarction (AMI) (HR of 2.17, p = 0.049) and chronic obstructive pulmonary disease (COPD) (HR of 3.13, p = 0.015). The percentage of biventricular stimulation at 6 months was identified as protective factor of mortality ([HR] 0.97, p = 0.048). The independent predictors associated with the echocardiographic response were absence of mitral insufficiency, presence of left bundle branch block and percentage of biventricular stimulation. Conclusion: Mortality in patients submitted to CRT in a tertiary hospital was independently associated with age, presence of COPD and previous AMI. The percentage of biventricular pacing evaluated 6 months after resynchronizer implantation was independently associated with improved survival and echocardiographic response.

摘要：背景：临床研究显示，高达40%的患者对心脏再同步治疗（CRT）无应答，因此针对心力衰竭患者的合理筛选是CRT成功实施的关键。目的：评估巴西人群中患者的死亡预测因素及其对CRT的应答效果。方法：本研究为回顾性队列研究，纳入2008年至2014年巴西南部某三级医院接受CRT治疗的患者，患者生存情况通过巴西南里奥格兰德州卫生厅数据库进行评估。采用泊松回归分析评估超声心动图应答的预测因素，通过Cox回归及Kaplan-Meier曲线开展生存分析，以双侧p值<0.05作为具有统计学显著性的判定标准。结果：本研究共纳入170例患者，平均随访时长为1011±632天，总死亡率为30%。死亡的独立预测因素包括年龄（风险比[HR]=1.05，p=0.027）、既往急性心肌梗死（AMI）史（HR=2.17，p=0.049）以及慢性阻塞性肺疾病（COPD）史（HR=3.13，p=0.015）；术后6个月的双心室起搏百分比被确定为死亡的保护性因素（HR=0.97，p=0.048）。与超声心动图应答相关的独立预测因素包括无二尖瓣反流、左束支传导阻滞的存在以及双心室起搏百分比。结论：该三级医院接受CRT治疗的患者，其死亡风险与年龄、COPD病史及既往AMI史呈独立相关；术后6个月评估的双心室起搏百分比与患者生存改善及超声心动图应答呈独立相关。