Neuropsychological outcome after cardiac arrest: results from a sub-study of the targeted hypothermia versus targeted normothermia after out-of-hospital cardiac arrest (TTM2) trial.

BACKGROUND: Cognitive impairment is common following out-of-hospital cardiac arrest (OHCA), but the nature of the impairment is poorly understood. Our objective was to describe cognitive impairment in OHCA survivors, with the hypothesis that OHCA survivors would perform significantly worse on neuropsychological tests of cognition than controls with acute myocardial infarction (MI). Another aim was to investigate the relationship between cognitive performance and the associated factors of emotional problems, fatigue, insomnia, and cardiovascular risk factors following OHCA. METHODS: This was a prospective case-control sub-study of The Targeted Hypothermia versus Targeted Normothermia after Out-of-Hospital Cardiac Arrest (TTM2) trial. Eight of 61 TTM2-sites in Sweden, Denmark, and the United Kingdom included adults with OHCA of presumed cardiac or unknown cause. A matched non-arrest control group with acute MI was recruited. At approximately 7 months post-event, we administered an extensive neuropsychological test battery and questionnaires on anxiety, depression, fatigue, and insomnia, and collected information on the cardiovascular risk factors hypertension and diabetes. RESULTS: Of 184 eligible OHCA survivors, 108 were included, with 92 MI controls enrolled. Amongst OHCA survivors, 29% performed z-score ≤ - 1 (at least borderline-mild impairment) in ≥ 2 cognitive domains, 14% performed z-score ≤ - 2 (major impairment) in ≥ 1 cognitive domain while 54% performed without impairment in any domain. Impairment was most pronounced in episodic memory, executive functions, and processing speed. OHCA survivors performed significantly worse than MI controls in episodic memory (mean difference, MD = - 0.37, 95% confidence intervals [- 0.61, - 0.12]), verbal (MD = - 0.34 [- 0.62, - 0.07]), and visual/constructive functions (MD = - 0.26 [- 0.47, - 0.04]) on linear regressions adjusted for educational attainment and sex. When additionally adjusting for anxiety, depression, fatigue, insomnia, hypertension, and diabetes, executive functions (MD = - 0.44 [- 0.82, - 0.06]) were also worse following OHCA. Diabetes, symptoms of anxiety, depression, and fatigue were significantly associated with worse cognitive performance. CONCLUSIONS: In our study population, cognitive impairment was generally mild following OHCA. OHCA survivors performed worse than MI controls in 3 of 6 domains. These results support current guidelines that a post-OHCA follow-up service should screen for cognitive impairment, emotional problems, and fatigue. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03543371. Registered 1 June 2018.

Neuropsychological outcome after cardiac arrest: a prospective case control sub-study of the Targeted hypothermia versus targeted normothermia after out-of-hospital cardiac arrest trial (TTM2).

BACKGROUND: This study is designed to provide detailed knowledge on cognitive impairment after out-of-hospital cardiac arrest (OHCA) and its relation to associated factors, and to validate the neurocognitive screening of the Targeted Hypothermia versus Targeted Normothermia after Out-of-Hospital Cardiac Arrest trial (TTM2-trial), assessing effectiveness of targeted temperature management after OHCA. METHODS: This longitudinal multi-center clinical study is a sub-study of the TTM2-trial, in which a comprehensive neuropsychological examination is performed in addition to the main TTM2-trial neurocognitive screening. Approximately 7 and 24 months after OHCA, survivors at selected study sites are invited to a standardized assessment, including performance-based tests of cognition and questionnaires of emotional problems, fatigue, executive function and insomnia. At 1:1 ratio, a matched control group from a cohort of acute myocardial infarction (MI) patients is recruited to perform the same assessment. We aim to include 100 patients per group. Potential differences between the OHCA patients and the MI controls at 7 and 24 months will be analyzed with a linear regression, using composite z-scores per cognitive domain (verbal, visual/constructive, working memory, episodic memory, processing speed, executive functions) as primary outcome measures. Results from OHCA survivors on the main TTM2-trial neurocognitive screening battery will be compared with neuropsychological test results at 7 months, using sensitivity and specificity analyses. DISCUSSION: In this study we collect detailed information on cognitive impairment after OHCA and compare this to a control group of patients with acute MI. The validation of the TTM2 neurocognitive screening battery could justify its inclusion in routine follow-up. Our results may have a potential to impact on the design of future follow-up strategies and interventions after OHCA. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03543371 . Registered 1 June 2018.

Combined use of the Montreal Cognitive Assessment and Symbol Digit Modalities Test improves neurocognitive screening accuracy after cardiac arrest: A validation sub-study of the TTM2 trial.

AIM: To assess the merit of clinical assessment tools in a neurocognitive screening following out-of-hospital cardiac arrest (OHCA). METHODS: The neurocognitive screening that was evaluated included the performance-based Montreal Cognitive Assessment (MoCA) and Symbol Digit Modalities Test (SDMT), the patient-reported Two Simple Questions (TSQ) and the observer-reported Informant Questionnaire on Cognitive Decline in the Elderly-Cardiac Arrest (IQCODE-CA). These instruments were administered at 6-months in the Targeted Hypothermia versus Targeted Normothermia after Out-of-Hospital Cardiac Arrest (TTM2) trial. We used a comprehensive neuropsychological test battery from a TTM2 trial sub-study as a gold standard to evaluate the sensitivity and specificity of the neurocognitive screening. RESULTS: In our cohort of 108 OHCA survivors (median age = 62, 88% male), the most favourable cut-off scores were: MoCA < 26; SDMT z ≤ -1; IQCODE-CA ≥ 3.04. The MoCA (sensitivity 0.64, specificity 0.85) and SDMT (sensitivity 0.59, specificity 0.83) had a higher classification accuracy than the TSQ (sensitivity 0.28, specificity 0.74) and IQCODE-CA (sensitivity 0.42, specificity 0.60). When using the cut-points for MoCA or SDMT in combination to identify neurocognitive impairment, sensitivity improved (0.81, specificity 0.74), area under the curve = 0.77, 95% CI [0.69, 0.85]. The most common unidentified impairments were within the episodic memory and executive functions domains, with fewer false negative cases on the MoCA or SDMT combined. CONCLUSION: The MoCA and SDMT have acceptable diagnostic accuracy for screening for neurocognitive impairment in an OHCA population, and when used in combination the sensitivity improves. Patient and observer-reports correspond poorly with neurocognitive performance. CLINICALTRIALS: gov Identifier: NCT03543371.

Agreement between self-reported and objectively assessed physical activity among out-of-hospital cardiac arrest survivors.

BACKGROUND: Low level of physical activity is a risk factor for new cardiac events in out-of-hospital cardiac arrest (OHCA) survivors. Physical activity can be assessed by self-reporting or objectively by accelerometery. AIM: To investigate the agreement between self-reported and objectively assessed physical activity among OHCA survivors HYPOTHESIS: Self-reported levels of physical activity will show moderate agreement with objectively assessed levels of physical activity. METHOD: Cross-sectional study including OHCA survivors in Sweden, Denmark, and the United Kingdom. Two questions about moderate and vigorous intensity physical activity during the last week were used as self-reports. Moderate and vigorous intensity physical activity were objectively assessed with accelerometers (ActiGraph GT3X-BT) worn upon the right hip for 7 consecutive days. RESULTS: Forty-nine of 106 OHCA survivors answered the two questions for self-reporting and had 7 valid days of accelerometer assessment. More physically active days were registered by self-report compared with accelerometery for both moderate intensity (median 5 [3:7] vs. 3 [0:5] days; p < 0.001) and vigorous intensity (1 [0:3] vs. 0 [0:0] days; p < 0.001). Correlations between self-reported and accelerometer assessed physical activity were sufficient (moderate intensity: rs = 0.336, p = 0.018; vigorous intensity: rs = 0.375, p = 0.008), and agreements were fair and none to slight (moderate intensity: k = 0.269, p = 0.001; vigorous intensity: k = 0.148, p = 0.015). The categorization of self-reported versus objectively assessed physical activity showed that 26% versus 65% had a low level of physical activity. CONCLUSION: OHCA survivors reported more physically active days compared with the results of the accelerometer assessment and correlated sufficiently and agreed fairly and none to slightly.

Physical activity after cardiac arrest; protocol of a sub-study in the Targeted Hypothermia versus Targeted Normothermia after Out-of-Hospital Cardiac Arrest trial (TTM2).

AIMS: The primary aim of this study is to investigate whether out-of-hospital cardiac arrest (OHCA) survivors have lower levels of self-reported physical activity compared to a non-cardiac arrest (CA) control group who had acute myocardial infarction (MI). Additional aims are to explore potential predictors of physical inactivity (older age, female gender, problems with general physical function, global cognition, mental processing speed/attention, anxiety symptoms, depression symptoms, kinesiophobia, fatigue), and to investigate the relationship between self-reported and objectively measured physical activity among OHCA-survivors. METHODS: The Targeted Hypothermia versus Targeted Normothermia after Out-of-Hospital Cardiac Arrest trial (TTM2-trial) collects information regarding age, gender, self-reported physical activity, general physical function, global cognition and mental processing speed/attention at 6 months after OHCA. In this TTM2-trial cross-sectional prospective sub-study, participants at selected sites are invited to an additional follow-up meeting within 4 weeks from the main study follow-up. At this meeting, information regarding anxiety symptoms, depression symptoms, kinesiophobia and fatigue is collected. The OHCA-survivors are then provided with an objective measure of physical activity, a hip-placed accelerometer, to wear for one week, together with a training diary. At the end of the week, participants are asked to once again answer two self-reported questions regarding physical activity for that specific week. MI-controls attend a single follow-up meeting and perform the same assessments as the OHCA-survivors, except from wearing the accelerometer. We aim to include 110 OHCA-survivors and 110 MI-controls in Sweden, Denmark and the United Kingdom. CONCLUSION: The results from this sub-study will provide novel information about physical activity among OHCA-survivors. TRIAL REGISTRATION: Registered at ClinicalTrials.gov: NCT03543332, date of registration June 1, 2018.