Predicting long-term outcomes after cardiac arrest by using serum neutrophil gelatinase-associated lipocalin

Neutrophil gelatinase-associated lipocalin (NGAL) is secreted by various tissues in pathologic states. Previous studies reported that post-cardiac arrest serum NGAL levels correlate with short-term neurologic outcomes and survival. The aim of this study was to examine the associations between NGAL levels post-cardiac arrest and long-term outcomes and survival.

This prospective observational study and retrospective review included adult out-of-hospital cardiac arrest survivors who were treated by hypothermia-targeted temperature management. Serum NGAL was assessed at 0, 24, 48, and 72h after return of spontaneous circulation. The primary outcome was poor outcome at six months after cardiac arrest, defined as cerebral performance category score of 3-5. The secondary outcome was six-month mortality.

In total, 76 patients were analyzed. The patients with poor outcomes showed significantly higher NGAL levels at 24, 48 and 72h after cardiac arrest than the patients with good outcomes. Long-term survival rates were significantly lower in the high-NGAL group than in the low-NGAL group at each time point. Subgroup analysis of patients who survived 72h showed that only serum NGAL 72h after cardiac arrest had prognostic value for long-term outcomes (area under the receiver operating characteristic curve=0.72; p=0.02).

Post-cardiac arrest serum NGAL is associated with long-term outcomes and survival; particularly, three days post-cardiac arrest is the optimal time point for predicting long-term outcomes. However, the predictive power of NGAL is unsatisfactory, and it should be regarded as an additional prognostic modality.