Long term clinical outcomes in survivors after out-of-hospital cardiac arrest

Determinants of decision-making for the initiation of resuscitation: a mixed-methods systematic review of barriers and facilitators

AIM

This study aimed to comprehensively examine the factors influencing healthcare providers' decision-making for initiation of resuscitation (IOR).

BACKGROUND

In-hospital resuscitation survival hinges on timely and effective interventions. Despite guidelines, decision-making during resuscitation remains challenging, impacted by both clinical and non-clinical factors.

METHODS

A mixed-methods systematic review (MMSR) was conducted, searching PubMed, Web of Science, Scopus, and Embase in May 2024. Twenty peer-reviewed studies of adult in-hospital resuscitation decision-making (≥ 18 years) were included. Data were extracted and synthesized using the Joanna Briggs Institute (JBI) convergent integrated approach.

RESULTS

A database search yielded 4398 studies, of which 1216 were duplicates. After screening 3182 unique studies, 20 articles (five qualitative, 12 quantitative, three mixed methods) were included. Data synthesis identified three overarching themes: patient, provider, and system factors. These themes encompassed barriers and facilitators to IOR.

CONCLUSION

This review underscores the importance of understanding patient-related, provider-related, and system-related factors influencing IOR. By addressing these factors, healthcare organizations can improve resuscitation practices and outcomes. Future research should focus on enhancing collaboration, communication, and resource availability while considering non-medical factors in decision-making for IOR.

RELEVANCE TO CLINICAL PRACTICE

Understanding the multifaceted barriers and facilitators identified in this study can enhance the effectiveness of resuscitation protocols and ultimately improve patient outcomes during critical care situations.

Long-term major events after hospital discharge for out-of-hospital cardiac arrest

BACKGROUND

Cardiac arrest remains a global health issue with limited data on long-term outcomes, particularly regarding recurrent cardiovascular events in patients surviving out-of-hospital cardiac arrest. (OHCA). We aimed to describe the long-term occurrence of major cardiac event defined by hospital admission for cardiovascular events or death in OHCA hospital survivors, whichever came first. Our secondary objective were to assess separately occurrence of hospital admission and death, and to identify the factors associated with major event occurrence. We hypothesized that patients surviving an OHCA has a protracted increased risk of cardiovascular events, due to both presence of the baseline conditions that lead to OHCA, and to the cardiovascular consequences of OHCA induced acute ischemia-reperfusion.

METHODS

Consecutive OHCA patients from three hospitals of Sudden Death Expertise Center (SDEC) Registry, discharged alive from 2011 to 2015 were included. Long-term follow-up data were obtained using national inter-regime health insurance information system (SNIIRAM) database and the national French death registry. The primary endpoint was occurrence of a major event defined by hospital admission for cardiovascular events and death, whichever came first during the follow-up. The starting point of the time-to-event analysis was the date of hospital discharge. The follow-up was censored on the date of the first event. For patients without event, follow-up was censored on the date of December, 29th, 2016.

RESULTS

A total of 306 patients (mean age 57; 77% male) were analyzed and followed over a median follow-up of 3 years for hospital admission for cardiovascular event and 6 years for survival. During this period, 38% patients presented a major event. Hospital admission for cardiovascular events mostly occurred during the first year after the OHCA whereas death occurred more linearly during the all period. A previous history of chronic heart failure and coronary artery disease were independently associated with the occurrence of major event (HR 1.75, 95%CI[1.06-2.88] and HR 1.70, 95%CI[1.11-2.61], respectively), whereas post-resuscitation myocardial dysfunction, cardiogenic shock and cardiologic cause of cardiac arrest did not.

CONCLUSION

Survivors from OHCA must to be considered at high risk of cardiovascular event occurrence whatever the etiology, mainly during the first year following the cardiac arrest and should require closed monitoring.

Prediction of neurologic outcome after out-of-hospital cardiac arrest: An interpretable approach with machine learning

Out-of-hospital cardiac arrest (OHCA) is a critical condition with low survival rates. In patients with a return of spontaneous circulation, brain injury is a leading cause of death. In this study, we propose an interpretable machine learning approach for predicting neurologic outcome after OHCA, using information available at the time of hospital admission.

METHODS

The study population were 55 615 OHCA cases registered in the Swedish Cardiopulmonary Resuscitation Registry between 2010 and 2020. The dataset was split to training and validation sets (for model development) and test set (for evaluation of the final model). We used an XGBoost algorithm with stratified, repeated 10-fold cross-validation along with Optuna framework for hyperparameters tuning. The final model was trained on 10 features selected based on the importance scores and evaluated on the test set in terms of discrimination, calibration and bias-variance tradeoff. We used SHapley Additive exPlanations to address the 'black-box' model and align with eXplainable artificial intelligence.

RESULTS

The final model achieved: area under the receiver operating characteristic value 0.964 (95% confidence interval (CI) [0.960-0.968]), sensitivity 0.606 (95% CI [0.573-0.634]), specificity 0.975 (95% CI [0.972-0.978]), positive predictive value (PPV) 0.664 (95% CI [0.625-0.696]), negative predictive value (NPV) 0.969 (95% CI [0.966-0.972]), macro F1 0.803 (95% CI [0.788-0.816]), and showed a very good calibration. SHAP features with the highest impact on the model's output were:'ROSC on arrival to hospital', 'Initial rhythm asystole' and 'Conscious on arrival to hospital'.

CONCLUSIONS

The XGBoost machine learning model with 10 features available at the time of hospital admission showed good performance for predicting neurologic outcome after OHCA, with no apparent signs of overfitting.

Long-term survival following out-of-hospital cardiac arrest in women and men: Influence of comorbidities, social characteristics, and resuscitation characteristics

AIM

We aimed to study sex differences in long-term survival following out-of-hospital cardiac arrest (OHCA) compared to the general population, and determined associations for comorbidities, social characteristics, and resuscitation characteristics with survival in women and men separately.

METHODS

We followed 2,452 Danish (530 women and 1,922 men) and 1,255 Dutch (259 women and 996 men) individuals aged ≥25 years, who survived 30 days post-OHCA in 2009-2015, until 2019. Using Poisson regression analyses we assessed sex differences in long-term survival and sex-specific associations of characteristics mutually adjusted, and compared survival with an age- and sex-matched general population. The potential predictive value was assessed with the Concordance-index.

RESULTS

Post-OHCA survival was longer in women than men (adjusted incidence rate ratio (IRR) for mortality 0.74, 95%CI 0.61-0.89 in Denmark; 0.86, 95%CI 0.65-1.15 in the Netherlands). Both sexes had a shorter survival than the general population (e.g., IRR for mortality 3.07, 95%CI 2.55-3.70 and IRR 2.15, 95%CI 1.95-2.37 in Danish women and men). Higher age, glucose lowering medication, no dyslipidaemia medication, unemployment, and a non-shockable initial rhythm were associated with shorter survival in both sexes. Cardiovascular medication, depression/anxiety medication, living alone, low household income, and residential OHCA location were associated with shorter survival in men. Not living with children and bystander cardiopulmonary resuscitation provision were associated with shorter survival in women. The Concordance-indexes ranged from 0.51 to 0.63.

CONCLUSIONS

Women survived longer than men post-OHCA. Several characteristics were associated with long-term post-OHCA survival, with some sex-specific characteristics. In both sexes, these characteristics had low predictive potential.

The incidence, predictors, and causes of cardiac arrest in United States emergency departments

BACKGROUND

Emergency department cardiac arrest (EDCA) is a global public health challenge associated with high mortality rates and poor neurological outcomes. This study aimed to describe the incidence, risk factors, and causes of EDCA during emergency department (ED) visits in the U.S.

METHODS

This retrospective cohort study used data from the 2019 Nationwide Emergency Department Sample (NEDS). Adult ED visits with EDCA were identified using the cardiopulmonary resuscitation code. We used descriptive statistics and multivariable logistic regression, considering NEDS's complex survey design. The primary outcome measure was EDCA incidence.

RESULTS

In 2019, there were approximately 232,000 ED visits with cardiac arrest in the U.S. The incidence rate of EDCA was approximately 0.2%. Older age, being male, black race, low median household income, weekend ED visits, having Medicare insurance, and ED visits in non-summer seasons were associated with a higher risk of EDCA. Hispanic race was associated with a lower risk of EDCA. Certain comorbidities (e.g., diabetes and cancer), trauma centers, hospitals with a metropolitan and/or teaching program, and hospitals in the South were associated with a higher risk of EDCA. Depression, dementia, and hypothyroidism were associated with a lower risk of EDCA. Septicemia, acute myocardial infarction, and respiratory failure, followed by drug overdose, were the predominant causes of EDCA.

CONCLUSIONS

Some patients were disproportionately affected by EDCA. Strategies should be developed to target these modifiable risk factors, specifically factors within ED's control, to reduce the subsequent disease burden.

Incidence and Long-Term Outcomes of Acute Myocardial Infarction Among Survivors of Out-of-Hospital Cardiac Arrest

BACKGROUND

Despite the increasing long-term survival after out-of-hospital cardiac arrest (OHCA), the risk of subsequent acute myocardial infarction (AMI) remains poorly understood. We aimed to determine the incidence, predictors, and long-term outcomes of AMI among survivors of OHCA.

METHODS AND RESULTS

We assembled a retrospective cohort of 882 patients with OHCA who survived to 30 days or discharge from the hospital between 2010 and 2019. Survivors of OHCA had an increased risk of subsequent AMI, defined as AMI occurring 30 days after index OHCA or following discharge from the hospital after OHCA, compared with the general population when matched for age and sex (standardized incidence ratio, 4.64 [95% CI, 3.52-6.01]). Age-specific risks of subsequent AMI for men (standardized incidence ratio, 3.29 [95% CI, 2.39-4.42]) and women (standardized incidence ratio, 6.15 [95% CI, 3.27-10.52]) were significantly increased. A total of 7.2%, 8.3%, and 14.3% of survivors of OHCA had a subsequent AMI at 3 years, 5 years, and end of follow-up, respectively. Age at OHCA (hazard ratio [HR], 1.04 [95% CI, 1.02-1.06]) and past medical history of prior AMI, defined as any AMI preceding or during the index OHCA event (HR, 1.84 [95% CI, 1.05-3.22]), were associated with subsequent AMI, while an initial shockable rhythm was not (HR, 1.00 [95% CI, 0.52-1.94]). Survivors of OHCA with subsequent AMI had a higher risk of death (HR, 1.58 [95% CI, 1.12-2.22]) than those without.

CONCLUSIONS

Survivors of OHCA are at an increased risk of subsequent AMI compared with the general population. Prior AMI, but not an initial shockable rhythm, increases this risk, while subsequent AMI predicts death. Preventive measures for AMI including cardiovascular risk factor control and revascularization may thus improve outcomes in selected patients with cardiac pathogenesis.

Unveiling Breakthroughs in Post-resuscitation Supportive Care for Out-of-Hospital Cardiac Arrest Survivors: A Narrative Review

Survivors of out-of-hospital cardiac arrest (OHCA) experience significant mortality rates and neurological impairment, potentially attributed to the hypoxic-ischemic injury sustained amid the cardiac arrest episode. Post-resuscitation care plays a crucial role in determining outcomes for survivors of OHCA. Supportive therapies have proven to be influential in shaping these outcomes. However, targeting higher blood pressure or oxygen levels during the post-resuscitative phase has not been shown to offer any mortality or neurological benefits. In terms of maintaining hemodynamic instability after resuscitation, it is recommended to use norepinephrine rather than epinephrine. While extracorporeal cardiopulmonary resuscitation has shown promising results, targeted temperature management has been found ineffective in improving outcomes despite its previous potential. This review also investigates various challenges and barriers associated with the practical implementation of these supportive therapies in clinical settings. The review also highlights areas ripe for future research and proposes potential directions to further enhance post-resuscitation supportive care for OHCA survivors.

Long term survival and disease burden from out-of-hospital cardiac arrest in Singapore: a population-based cohort study

Background

Understanding the long-term outcomes and disability-adjusted life years (DALY) after out-of-hospital cardiac arrest (OHCA) is important to understand the overall health and disease burden of OHCA respectively, but data in Asia remains limited. We aimed to quantify long-term survival and the annual disease burden of OHCA within a national multi-ethnic Asian cohort.

Methods

We conducted an open cohort study linking the Singapore Pan-Asian Resuscitation Outcomes Study (PAROS) and the Singapore Registry of Births and Deaths from 2010 to 2019. We performed Cox regression, constructed Kaplan-Meier curves, and calculated DALYs and standardised mortality ratios (SMR) for each year of follow-up.

Results

We analysed 802 cases. The mean age was 56.0 (SD 17.8). Most were male (631 cases, 78,7%) and of Chinese ethnicity (552 cases, 68.8%). At one year, the SMR was 14.9 (95% CI:12.5-17.8), decreasing to 1.2 (95% CI:0.7-1.8) at three years, and 0.4 (95% CI:0.2-0.8) at five years. Age at arrest (HR:1.03, 95% CI:1.02-1.04, p < 0.001), shockable presenting rhythm (HR:0.75, 95% CI:0.52-0.93, p = 0.015) and CPC category (HR:4.62, 95% CI:3.17-6.75, p < 0.001) were independently associated with mortality. Annual DALYs due to OHCA varied from 304.1 in 2010 to 849.7 in 2015, then 547.1 in 2018. Mean DALYs decreased from 12.162 in 2010 to 3.599 in 2018.

Conclusions

OHCA survivors had an increased mortality rate for the first three years which subsequently normalised compared to that of the general population. Annual OHCA disease burden in DALY trended downwards from 2010 to 2018. Improved surveillance and OHCA treatment strategies may improve long-term survivorship and decrease its global burden.

Funding

National Medical Research Council, Singapore, under the Clinician Scientist Award (NMRC/CSA-SI/0014/2017) and the Singapore Translational Research Investigator Award (MOH-000982-01).

Long-term Survival After Out-of-Hospital Cardiac Arrest: A Systematic Review and Meta-analysis

Importance

Data on long-term survival beyond 12 months after out-of-hospital cardiac arrest (OHCA) of a presumed cardiac cause are scarce.

Objective

To investigate the long-term survival of adult patients after surviving the initial hospital stay for an OHCA.

Data Sources

A systematic search of the EMBASE and MEDLINE databases was performed from database inception to March 25, 2021.

Study Selection

Clinical studies reporting long-term survival after OHCA were selected based on predefined inclusion and exclusion criteria according to a preregistered study protocol.

Data Extraction and Synthesis

Patient data were reconstructed from Kaplan-Meier curves using an iterative algorithm and then pooled to generate survival curves. As a separate analysis, an aggregate data meta-analysis was performed.

Main Outcomes and Measures

The primary outcome was long-term survival (>12 months) after OHCA for patients surviving to hospital discharge or 30 days after OHCA.

Results

The search identified 15 347 reports, of which 21 studies (11 800 patients) were included in the Kaplan-Meier-based meta-analysis and 33 studies (16 933 patients) in an aggregate data meta-analysis. In the Kaplan-Meier-based analysis, the median survival time for patients surviving to hospital discharge was 5.0 years (IQR, 2.3-7.9 years). The estimated survival rates were 82.8% (95% CI, 81.9%-83.7%) at 3 years, 77.0% (95% CI, 75.9%-78.0%) at 5 years, 63.9% (95% CI, 62.3%-65.4%) at 10 years, and 57.5% (95% CI, 54.8%-60.1%) at 15 years. Compared with patients with a nonshockable initial rhythm, patients with a shockable rhythm had a lower risk of long-term mortality (hazard ratio, 0.30; 95% CI, 0.23-0.39; P < .001). Different analyses, including an aggregate data meta-analysis, confirmed these results.

Conclusions and Relevance

In this comprehensive systematic review and meta-analysis, long-term survival after 10 years in patients surviving the initial hospital stay after OHCA was between 62% and 64%. Additional research is needed to understand and improve the long-term survival in this vulnerable patient population.

Long-Term Outcome After Out-of-Hospital Cardiac Arrest: An Utstein-Based Analysis

Background: No data are available regarding long-term survival of out-of-hospital cardiac arrest (OHCA) patients based on different Utstein subgroups, which are expected to significantly differ in terms of survival. We aimed to provide the first long-term survival analysis of OHCA patients divided according to Utstein categories.

Methods: We analyzed all the 4,924 OHCA cases prospectively enrolled in the Lombardia Cardiac Arrest Registry (Lombardia CARe) from 2015 to 2019. Pre-hospital data, survival, and cerebral performance category score (CPC) at 1, 6, and 12 months and then every year up to 5 years after the event were analyzed for each patient.

Results: A decrease in survival was observed during the follow-up in all the Utstein categories. The risk of death of the “all-EMS treated” group exceeded the general population for all the years of follow-up with standardized mortality ratios (SMRs) of 23 (95%CI, 16.8–30.2), 6.8 (95%CI, 3.8–10.7), 3.8 (95%CI, 1.7–6.7), 4.05 (95%CI, 1.9–6.9), and 2.6 (95%CI, 1.03–4.8) from the first to the fifth year of follow-up. The risk of death was higher also for the Utstein categories “shockable bystander witnessed” and “shockable bystander CPR”: SMRs of 19.4 (95%CI, 11.3–29.8) and 19.4 (95%CI, 10.8–30.6) for the first year and of 6.8 (95%CI, 6.6–13) and 8.1 (95%CI, 3.1–15.3) for the second one, respectively. Similar results were observed considering the patients discharged with a CPC of 1–2.

Conclusions: The mortality of OHCA patients discharged alive from the hospital is higher than the Italian standard population, also considering those with the most favorable OHCA characteristics and those discharged with good neurological outcome. Long-term follow-up should be included in the next Utstein-style revision.

Neuron-Specific Enolase (NSE) Predicts Long-Term Mortality in Adult Patients after Cardiac Arrest: Results from a Prospective Trial

Background: We investigated whether Neuron-specific enolase (NSE) serum concentration predicts long-term mortality and poor neurological outcome in adult cardiac arrest patients. Methods: Within this prospective observational study, we included consecutive adult patients admitted to the intensive care unit (ICU) after cardiac arrest. NSE was measured upon ICU admission and on days 1, 2, 3, 5 and 7. Results: Of 403 patients, 176 (43.7%) survived. Median follow-up duration was 43.7 months (IQR 14.3 to 63.0 months). NSE levels on day 3 were increased more than threefold in non-survivors compared to survivors (median NSE (ng/mL) 19.8 (IQR 15.7 to 27.8) vs. 72.6 (IQR 26 to 194)) and showed the highest prognostic performance for mortality compared to other days of measurement, with an AUC of 0.81 and an adjusted hazard ratio of 1.55 (95% CI 1.41 to 1.71, p < 0.001). Subgroup analysis showed an excellent sensitivity and negative predictive value of 100% of NSE in patients <54 years of age. Conclusion: NSE measured three days after cardiac arrest is associated with long-term mortality and neurological outcome and may provide prognostic information that improves clinical decision making. Particularly in the subgroup of younger patients (<54 years), NSE showed excellent negative predictive value.

Increased 5-year risk of stroke, atrial fibrillation, acute coronary syndrome, and heart failure in out-of-hospital cardiac arrest survivors compared with population controls: A nationwide registry-based study

AIM

Long-term risks of stroke, atrial fibrillation, or flutter (AF), acute coronary syndrome (ACS), and heart failure (HF) among survivors of out-of-hospital cardiac arrest (OHCA) are unknown. We aimed to examine 5-year risks of these outcomes among 30-day survivors of OHCA.

METHODS

Thirty-day survivors of OHCA without a prior (or within 30 days after cardiac arrest) history of stroke, AF, ACS, or HF and population controls without a prior history of these conditions were identified using Danish nationwide registries. Five-year risks of stroke, AF, ACS, and HF standardized to the distributions of age, sex, and comorbidities among OHCA survivors and controls were obtained using multivariable regression.

RESULTS

Of 4,362 30-day OHCA-survivors, 1,051 were stroke-, AF-, ACS-, and HF-naïve and matched with controls using age, sex, and time of OHCA event. Absolute five-year risks for OHCA survivors vs. controls were for stroke: 6.3% [95% confidence interval (CI) 4.1-8.5] vs. 2.0% [1.6-2.5], AF: 7.9% [5.7-10.2] vs. 2.6% [2.1-3.1], ACS: 5.0% [3.2-6.8] vs. 1.5% [1.1-1.9], and HF: 12.7% [10.1-15.4] vs. 1.2% [0.9-1.6], respectively. Corresponding relative risks were 3.18 [95% CI 1.76-4.61] for stroke, 3.03 [1.93-4.14] for AF, 3.23 [1.69-4.77] for ACS, and 10.40 [6.57-14.13] for HF.

CONCLUSION

When compared with population controls, OHCA survivors had significantly increased five-year risks of incident stroke, AF, ACS, and HF.

Targeted temperature management and early neuro-prognostication after cardiac arrest

Targeted temperature management (TTM) is a recommended neuroprotective intervention for coma after out-of-hospital cardiac arrest (OHCA). However, controversies exist concerning the proper implementation and overall efficacy of post-CA TTM, particularly related to optimal timing and depth of TTM and cooling methods. A review of the literature finds that optimizing and individualizing TTM remains an open question requiring further clinical investigation. This paper will summarize the preclinical and clinical trial data to-date, current recommendations, and future directions of this therapy, including new cooling methods under investigation. For now, early induction, maintenance for at least 24 hours, and slow rewarming utilizing endovascular methods may be preferred. Moreover, timely and accurate neuro-prognostication is valuable for guiding ethical and cost-effective management of post-CA coma. Current evidence for early neuro-prognostication after TTM suggests that a combination of initial prediction models, biomarkers, neuroimaging, and electrophysiological methods is the optimal strategy in predicting neurological functional outcomes.