Hypernatremia predicts adverse cardiovascular and neurological outcomes after SAH

Introduction: Abnormalities of serum sodium are common after subarachnoid hemorrhage (SAH) and have been linked to poor outcome. This study analyzed whether abnormal serum sodium levels are associated with cardiac outcomes and mortality after subarachnoid hemorrhage (SAH). Methods: In a prospective cohort study of SAH patients, the primary predictor variable was subjects' sodium level. Hypernatremia was defined as sodium >143 mmol/L and hyponatremia was <133 mmol/L. Cardiac troponin I (cTi) was measured and echocardiography was performed on three study days. Dichotomous outcome variables were cTi>1.0 mu g/L, left-ventricular ejection fraction (LVEF) <50%, presence (vs absence) of regional wall motion abnormalities (RWMA) of the LV, pulmonary edema, and death. Additional analyses studied the degree of hypernatremia and sodium supplementation, and the temporal relationship between hypernatremia and cardiac outcomes. Results: The study included 214 subjects. Forty-eight subjects (22%) were hypernatremic on at least one study day, and 45 (21%) were hyponatremic. After multivariate adjustment, hypernatremia was an independent predictor of LVEF <50% (OR 4.7, CI 1.3-16.2, p=0.015), elevated cTi (OR 3.7, CI 1.2-11.9, p=0.028), and pulmonary edema (OR 4.1 CI 1.4-1.5, p=0.008). It was not, however a statistically significant predictor of mortality (p=0.075). Conclusion: In the acute period after SAH, hypernatremia is associated with adverse cardiac outcomes and death. SAH patients with hypernatremia should be monitored for evidence of cardiac dysfunction.