Plasma tau protein in comatose patients after cardiac arrest treated with therapeutic hypothermia.

Background Neurological outcome after cardiac arrest (CA) is difficult to predict in the acute phase. In this pilot study, we assessed blood levels of tau protein as a prognostic marker for the neurological outcome after 6 months in patients treated with hypothermia after resuscitation from CA. Methods 22 unconscious patients resuscitated after CA were treated with mild hypothermia (32–34°C) for 26 h. Blood samples were collected at 2, 6, 12, 24, 48, and 96 h after CA, and the concentration of tau protein was analyzed. Neurological outcome was assessed with the Glasgow-Pittsburgh cerebral performance category (CPC) scale at intensive care unit (ICU) discharge and after 6 months. The higher of the two CPC scores was used. Results At ICU discharge, 21/22 patients were alive, of whom 10 had a good (CPC 1–2) outcome. After 6 months, 15/22 patients were alive, of whom 14 had a good outcome. Tau protein levels were higher among those with a poor outcome at 48 h and 96 h. At 96 h sampling, tau concentration predicted a poor outcome (CPC 3–5) with a sensitivity of 71% and a specificity of 93%. Conclusions Although in a pilot study, a late increase in plasma tau protein seems to be associated with a worse outcome after hypothermia treatment after CA, although more studies are needed.