Cognitive Function After Cardiac Arrest | Journal Scan

Feb 25, 2015
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Authors:
Lilja G, Nielsen N, Friberg H, et al.
Citation:
Cognitive Function in Survivors of Out-of-Hospital Cardiac Arrest After Target Temperature Management at 33ºC Versus 36ºC. Circulation 2015;Feb 13:[Epub ahead of print].
Summary By:
Thomas C. Crawford, MD, FACC

Study Questions:

Does a target temperature of 33ºC compared to 36ºC offer better neuroprotection after out-of-hospital cardiac arrest (OHCA)?

Methods:

The Target Temperature Management trial randomized cardiac arrest survivors to temperature control at 33°C or 36°C. Survivors were interviewed face-to-face, and their cognitive function was tested for memory, executive functions, and attention/mental speed. Patients with ST-segment elevation myocardial infarction (STEMI) without cardiac arrest served as the control group.

Results:

A total of 652 cardiac arrest survivors were randomized. Survival at 180 days was 52%, and 287 survivors were interviewed. The control group consisted of 119 patients with STEMI not complicated by cardiac arrest. Half of the cardiac arrest survivors had cognitive impairment, which was mostly mild. Cognitive outcome did not differ (p > 0.30) between the two temperature groups. Compared to STEMI-controls, attention/mental speed was more affected among cardiac arrest patients, but results for memory and executive functioning were similar.

Conclusions:

The authors concluded that cognitive function was similar in survivors of OHCA when targeting a temperature of 33°C and 36°C. Cognitive impairment detected in cardiac arrest survivors was also common in matched STEMI-controls not having had a cardiac arrest.

Perspective:

This study confirms the results of prior reports that cognitive impairment is common among OHCA survivors and affects about half of them. Interestingly, the control group of disease-matched STEMI patients had cognitive deficits similar to those after OHCA, with the exception of the attention and processing speed, where OHCA survivors did much worse. This study cautions us not to assign all cognitive impairment in OHCA survivors to the cardiac arrest. Impaired memory was just as common in STEMI patients as OHCA patients, suggesting that underlying vascular disease may be the main driver of the cognitive decline, rather than the cardiac arrest itself.

Keywords: Out-of-Hospital Cardiac Arrest, Heart Arrest, Hypothermia, Temperature, Cognition, Brain Injuries, Myocardial Infarction, Acute Coronary Syndrome, Survivors, Control Groups, Vascular Diseases, Secondary Prevention


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