Background: Although the incidence of sudden cardiac death (SCD) is high among haemodialysis (HD) patients, there are few papers available on this topic. The aim of this study on a single-centre HD population observed over a 10 year period was to identify patient- and HD-related specific factors that might be associated with a higher risk of SCD.
Methods: The study included 123 patients (76 men; age 29-79 years) undergoing renal replacement therapy at our dialysis unit for at least 6 months. For each patient, routine laboratory tests were performed monthly, blood pressure was measured both at the start and the end of each dialysis session, haemoglobin and pre-dialysis serum K(+) were determined weekly, serum iPTH was assessed thrice yearly, and an echocardiographic study was performed annually to determine the left ventricular mass index (LVMi). The prevalence of cardiovascular (CV) co-morbidities, and the incidence of new events were also recorded.
Results: During the 10 years, 85 patients died-16 from SCD, 30 from cardiac causes (CC) other than SCD, and 39 from other causes (OC); 38 patients were still alive (AL) at the end of the observation period. Comparative analysis of SCD, CC, OC and AL, reveals that the male prevalence (13/3) was higher in SCD than in AL, while AL were younger than the deceased patients regardless of the cause of death (P<0.0001; ANOVA), the duration of arterial hypertension was higher in SCD (129+/-104 months; P = 0.0005; ANOVA), despite similar antihypertensive therapies, and the difference between LVMi at end-point and at inception (deltaLVMi) was significantly higher in SCD [+56+/-38 g/m(2) body surface area] compared with OC (-5+/-35), AL (-17+/-25) and even CC (7+/-30) (P<0.0001; ANOVA); finally, the prevalence of patients with ischaemic heart disease (IHD) was higher in the SCD group (11/5; P<0.0001, chi(2)). Univariate Cox regression analysis demonstrated that the factors increasing the risk of SCD were IHD (P = 0.002), the worsening of left ventricular hypertrophy (LVH) (P<0.0001), and the presence of long-lasting arterial hypertension (P = 0.001). An increase in LVH was the sole risk factor for SCD when comparing SCD with CC patients (P = 0.003). By multivariate Cox regression analysis deltaLVMi was identified as the strongest predictor of SCD (P<0.0001).
Conclusion: While confirming the role of common CV risk factors for SCD in dialysis patients such as IHD and arterial hypertension, this study is the first to demonstrate that the worsening of LVH is the strongest predictor of sudden death.