Supplementary Material for: Novel Approach to Cardiovascular Outcome Prediction in Haemodialysis Patients

<b><i>Background:</i></b> Cardiovascular mortality is high in haemodialysis (HD) patients. Arterial stiffness and global longitudinal strain (GLS) are important non-atheromatous cardiovascular risk predictors. No study has encompassed both parameters in a combined model for prediction of outcomes in HD patients. This is important because left ventricular (LV) dysfunction can result from fibrotic remodelling secondary to increased arterial stiffness. <b><i>Methods:</i></b> Two hundred and nineteen HD patients had pulse wave velocity (PWV) and echocardiography (including GLS) assessments. Patients were followed-up until death, transplantation or November 16, 2015, whichever happened first. Pearson's correlation coefficient was used to determine factors associated with PWV and GLS. A multivariable Cox regression model investigated factors associated with all-cause, cardiac death and events. <b><i>Results:</i></b> One hundred and ninety eight HD patients had full datasets (median age 64.2, 68.7% males) with a mean LV ejection fraction (LVEF) of 61.7 ± 10.1% and GLS -13.5 ± 3.3%; 51% had LV hypertrophy. Forty eight deaths (15 cardiac) and 44 major cardiac events occurred during a median follow-up of 27.6 (25th-75th percentile, 17.3-32.7) months. In separate survival models, PWV and GLS were independently associated with all-cause mortality; however, in a combined model, LV mass indexed to height^2.7 (LVMI/HT^2.7; adjusted hazard ratio (HR) 1.02, 95% CI 1.00-1.04) and PWV (adjusted HR 1.23, 95% CI 1.03-1.47) were significant. PWV was neither associated with cardiac death nor associated with related cardiac events. However, GLS was associated with cardiac death (adjusted HR 1.24, 95% CI 1.00-1.54) and cardiac events (adjusted HR 1.13, 95% CI 1.03-1.25). <b><i>Conclusions:</i></b> PWV and LVMI/HT^2.7 were superior to GLS in prediction of all-cause mortality. However, GLS was associated with cardiac death and events even when accounting for LVEF and LVMI/HT^2.7.

<b><i>背景：</i></b> 血液透析（haemodialysis, HD）患者的心血管病死率居高不下。动脉僵硬度与整体纵向应变（global longitudinal strain, GLS）是重要的非动脉粥样硬化性心血管风险预测因子。目前尚无研究将这两项参数纳入联合模型以预测血液透析患者的临床结局，这一点具有重要临床意义，因为左心室（left ventricular, LV）功能障碍可继发于动脉僵硬度升高引发的纤维化重构。
<b><i>方法：</i></b> 本研究纳入219例血液透析患者，对其开展脉搏波传导速度（pulse wave velocity, PWV）与超声心动图（含整体纵向应变检测）评估。对患者进行随访，直至其发生死亡、肾移植或至2015年11月16日（以最先发生的事件为准）。采用皮尔逊相关系数分析与PWV及GLS相关的影响因素；通过多变量Cox回归模型分析与全因死亡、心源性死亡及不良心脏事件相关的危险因素。
<b><i>结果：</i></b> 最终纳入198例资料完整的血液透析患者，年龄中位数为64.2岁，男性占比68.7%；患者的平均左心室射血分数（left ventricular ejection fraction, LVEF）为61.7±10.1%，GLS为-13.5±3.3%；51%的患者合并左心室肥厚。中位随访27.6个月（四分位间距17.3~32.7个月）期间，共发生48例死亡（其中15例为心源性死亡）与44例主要心脏不良事件。单因素生存模型分析显示，PWV与GLS均为全因死亡率的独立相关因素；但在联合模型中，经身高²·⁷校正的左心室质量指数（LVMI/HT²·⁷；校正后风险比（hazard ratio, HR）=1.02，95%置信区间（CI）：1.00~1.04）与PWV（校正后HR=1.23，95%CI：1.03~1.47）仍具有统计学意义。PWV与心源性死亡及相关心脏不良事件均无关联；而GLS则与心源性死亡（校正后HR=1.24，95%CI：1.00~1.54）及主要心脏不良事件（校正后HR=1.13，95%CI：1.03~1.25）显著相关。
<b><i>结论：</i></b> 在全因死亡率预测方面，PWV与LVMI/HT²·⁷的效能优于GLS；但即便在校正LVEF及LVMI/HT²·⁷后，GLS仍与心源性死亡及心脏不良事件存在独立关联。