Role of genetic and electrolyte abnormalities in prolonged QTc interval and sudden cardiac death in end-stage renal disease patients.

BACKGROUND: Patients with end-stage renal disease have very high mortality. In individuals on hemodialysis, cardiovascular deaths account for ~50% of all deaths in this population, mostly due to arrhythmia. To determine the causes of these arrhythmic deaths is essential in order to adopt preventive strategies. The main objective of this study was to investigate whether, the presence of QTc interval alterations, from electrolyte abnormalities or presence of rare genetic variants, could have a relationship with sudden arrhythmogenic deaths in end-stage renal disease patients. METHODS: We recorded the pre- and post-dialysis QTc interval in 111 patients undergoing hemodialysis. In 47 of them, we analyzed 24 SCD-related genes including the most prevalent genes associated with long QT syndrome using a custom resequencing panel. RESULTS: We found a positive although not significant association between the presence of long QTc and mortality in a subset of end-stage renal disease patients. In addition, in five patients with long QTc only after dialysis (21.7%) we detected rare potentially pathogenic genetic variants. Three out of these five carriers subsequently died suddenly. CONCLUSIONS: Genetic background may be determinant in the risk of sudden cardiac death in these patients. We recommend evaluating the QTc interval before and after hemodialysis, and performing a genetic analysis of individuals with long QTc after hemodialysis.

Microbiological profile of peritoneal dialysis peritonitis and predictors of hospitalization.

Peritonitis, the major complication of peritoneal dialysis (PD), is associated with high morbidity and mortality. It is a major cause of hospitalization and transfer to hemodialysis. In the present study, we aimed to identify predictors of hospitalization in PD-related peritonitis and to examine its microbiology profile over time in our unit to determine the best therapeutic approach. We studied all peritonitis episodes that occurred in a 6-year period (January 1, 2004, to December 31, 2009), evaluating whether adequate treatment could be delivered on an outpatient basis. During the study period, 411 patients were on PD, and 229 peritonitis episodes were recorded in 91 patients. Peritonitis were treated according to unit protocol. The average hospital stay was 11.6 +/- 6.6 days. We observed an increase of Streptococcus (to 19.4% from 7.7%) and a stabilization of coagulase-negative Staphylococcus, S. epidermidis, and S. aureus (from 9.5%, 22.6%, and 3.2% to 7.7%, 30.8%, and 3.8% respectively) peritonitis episodes. The main risk factors for hospitalization were fungal infection, poor 72-hour outcome, inability to perform self-care, and age greater than 80 years. We observed a decline in the incidence of peritonitis, and despite changes in its microbiology profile, no loss of sensitivity to antibiotics used was observed.