Supplementary Material for: The Association of Echocardiographic Peak Systolic Strain Rate with Cardiovascular Outcomes in Haemodialysis Patients

Background/Aims: Echocardiographic abnormalities of systolic function can be detected earlier with advancing echocardiographic technologies. Given the high prevalence of left ventricular hypertrophy in dialysis patients, we hypothesised that one such marker of strain, peak systolic strain rate (SR) would demonstrate association with cardiovascular outcome in a haemodialysis cohort. Methods: Recruited prevalent haemodialysis patients underwent standard transthoracic echocardiography as part of a detailed cardiovascular assessment on a non-dialysis day during a short inter-dialytic midweek break. Patients were followed up to mortality and cardiovascular end points. Multivariate Cox proportional hazard models were built to determine the association of above versus below median SR in a model adjusted for confounding factors. Results: 183 patients were enrolled and followed up for a median 925 days. Median age was 64.9 years, prevalence of LVH 55%, and median SR -0.86 (-1.00 to -0.72). An SR greater than -0.86 S-1 (less negative) had a hazard ratio (HR) of 2.32 (1.36 to 3.95) in association with all-cause mortality after adjustment for EF, age, smoking history, MI, previous transplant, albumin and systolic blood pressure. For cardiovascular mortality, the HR was 2.343 (0.99 to 5.553) p =0.046. The only echocardiographic parameter independently associated with MACE was above median E/e (HR 2.09 [1.03 to 4.24], p=0.04). No echocardiographic parameter was associated with heart failure episodes. Conclusion: SR demonstrates association with outcome in this population and highlights the consideration that such sub-clinical cardiac changes should be routinely sought when referring haemodialysis patients for cardiac assessments.背景与目的：随着超声心动图技术的迭代升级，收缩功能异常可被更早识别。鉴于血液透析（haemodialysis）患者左心室肥厚（left ventricular hypertrophy, LVH）的高患病率，我们提出假说：作为心肌应变标志物之一的峰值收缩应变率（peak systolic strain rate, SR），可在血液透析队列中与心血管不良结局存在关联。 方法：本研究纳入的维持性血液透析患者，于透析间期周中休诊的非透析日接受标准经胸超声心动图（transthoracic echocardiography）检查，作为详细心血管评估的组成部分。对所有入组患者进行随访，记录其死亡及心血管终点事件。构建多因素Cox比例风险模型，在校正混杂因素后，对比应变率高于与低于中位数水平的患者结局差异。 结果：共纳入183例患者，中位随访时长为925天。受试者中位年龄为64.9岁，左心室肥厚患病率为55%，中位应变率为-0.86（-1.00~-0.72）S⁻¹。在校正射血分数（ejection fraction, EF）、年龄、吸烟史、心肌梗死（myocardial infarction, MI）、既往移植史、白蛋白水平及收缩压后，应变率高于-0.86 S⁻¹（负值更小）的患者，其全因死亡率的风险比（hazard ratio, HR）为2.32（95%置信区间：1.36~3.95）。针对心血管死亡率，该风险比（HR）为2.343（95%置信区间：0.99~5.553），P=0.046。唯一与主要不良心血管事件（major adverse cardiovascular events, MACE）独立相关的超声心动图参数为E/e比值高于中位数（HR=2.09，95%置信区间：1.03~4.24，P=0.04）。未发现任何超声心动图参数与心力衰竭发作存在关联。 结论：本研究队列中，应变率与患者临床结局存在显著关联，这提示临床医师在转诊血液透析患者接受心血管评估时，应常规筛查此类亚临床心脏改变。