André Wajner

Preconditioning Prevents the Inhibition of Na+,K+-ATPase Activity after Brain Ischemia

Application of single transient forebrain ischemia (ISC) in adult Wistar rats, lasting 2 or 10 min, caused inhibition of Na+,K+-ATPase activity in cytoplasmic membrane fractions of hippocampus and cerebral cortex immediately after the event. In the 2-min ISC group followed by 60 min of reperfusion, the enzyme inhibition was maintained in the cortex, while there was an increase in hippocampal enzyme activity; both effects were over 1 day after the event. However, in the 10-min ISC group enzyme inhibition had been maintained for 7 days in both cerebral structures. Interestingly, ischemic preconditioning (2-min plus 10-min ISC, with a 24-hour interval in between) prevented the inhibitory effect of ischemia/reperfusion on Na+,K+-ATPase activity observed either after a single insult of 2 min or 10 min ischemia. We suggest that the maintenance of Na+,K+-ATPase activity afforded by preconditioning be related to cellular neuroprotection.

Causes and Predictors of In-Hospital Mortality in Patients Admitted with or for Heart Failure at a Tertiary Hospital in Brazil

Background Although heart failure (HF) has high morbidity and mortality, studies in Latin America on causes and predictors of in-hospital mortality are scarce. We also do not know the evolution of patients with compensated HF hospitalized for other reasons. Objective To identify causes and predictors of in-hospital mortality in patients hospitalized for acute decompensated HF (ADHF), compared to those with HF and admitted to the hospital for non-HF related causes (NDHF). Methods Historical cohort of patients hospitalized in a public tertiary hospital in Brazil with a diagnosis of HF identified by the Charlson Comorbidity Index (CCI). Results A total of 2056 patients hospitalized between January 2009 and December 2010 (51% men, median age of 71 years, length of stay of 15 days) were evaluated. There were 17.6% of deaths during hospitalization, of which 58.4% were non-cardiovascular (63.6% NDHF vs 47.4% ADHF, p = 0.004). Infectious causes were responsible for most of the deaths and only 21.6% of the deaths were attributed to HF. The independent predictors of in-hospital mortality were similar between the groups and included: age, length of stay, elevated potassium, clinical comorbidities, and CCI. Renal insufficiency was the most relevant predictor in both groups. Conclusion Patients hospitalized with HF have high in-hospital mortality, regardless of the primary reason for hospitalization. Few deaths are directly attributed to HF; Age, renal function and levels of serum potassium, length of stay, comorbid burden and CCI were independent predictors of in-hospital death in a Brazilian tertiary hospital.