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.