Extracorporeal cardiopulmonary resuscitation: a national study on the association between survival and biomarkers of hypoperfusion, inflammation, and organ failure

Background

In refractory out-of-hospital cardiac arrest (OHCA) with prolonged whole-body ischemia, global tissue injury proceeds even after establishment of circulation with extracorporeal cardiopulmonary resuscitation (ECPR).

Purpose

We aimed to investigate the role of biomarkers reflecting hypoperfusion, inflammation, and organ injury in prognostication of patients with refractory OHCA managed with ECPR.

Methods

This nationwide retrospective study included 226 adults with refractory OHCA managed with ECPR in Denmark (2011–2020). Biomarkers at admission and consecutively two days after ECPR initiation were retrieved. Odds ratio (OR) of 90-day survival were assessed by logistic regression analyses. Cut-off values were calculated from area under the curve (AUC) via the Youden index.

Results

Fifty-six patients (25%) survived to hospital discharge, all were still alive after 90-days and 91% had a favorable neurological status at discharge. Factors independently associated with 90-day survival were: male sex, shockable presenting rhythm, low flow time, platelets, pH, lactate, C-reactive protein, lactate dehydrogenase (LDH), alkaline phosphatase (ALP), and creatine kinase MB (CK-MB) level. Comparing the ability of standard predictive variables (age, sex, shockable presenting rhythm, witnessed arrest, and low flow time) and selected biomarkers (from multivariate analyses) in predicting 90-day survival, biomarkers day 2 after OHCA were significantly better than standard variables (AUC 0.79 vs. 0.56, p=0.01).

Conclusion

Biomarkers of hypoperfusion (low lactate and high pH), inflammation (high platelets and CRP), and organ failure (low LDH, ALP, and CK-MB) were independently associated with 90-day survival. Biomarkers on day 2 after OHCA (d-dimer, ALP, and CK-MB) were more predictive of 90-day survival than standard predictive variables.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Odense University Hospital's and Rigshospitalet's Common Research Foundation

Selection of patients for mechanical circulatory support for refractory out-of-hospital cardiac arrest: a Danish nationwide multicenter study

Background

Extracorporeal cardiopulmonary resuscitation (ECPR) is a potential salvage therapy for selected patients with refractory out-of-hospital cardiac arrest (OHCA).

Purpose

The objective of this study was to describe the characteristics of potential ECPR patients.

Methods

This retrospective, observational cohort study included 579 patients admitted with refractory OHCA for possible ECPR at all tertiary cardiac arrest centers in Denmark between 2015 and 2020. Presenting characteristics, reasons for refraining from ECPR, and survival to hospital discharge were recorded.

Results

After initial evaluation, 221 patients (38%) proceeded to ECPR, and 358 (62%) were considered futile. Median prehospital low-flow time was 70 minutes [interquartile range 56–85] in ECPR patients and 62 minutes [48–81] in no-ECPR patients, p<0.001. Intra arrest transport was more than 50 km in 92 (42%) ECPR patients and 135 in no-ECPR patients (38%), p=0.25. Treatment decision was taken by a team of three specialists in 513 cases (97%). The leading cause for not initiating ECPR was duration of low flow time (39%). Severe metabolic derangement and low end-tidal CO2 (ETCO2) were contributing factors in 35% and 31%, respectively, Figure 1. 83% of the patients had two or more contributing factors recorded as reasons for not initiating ECPR, Figure 2. The most prevailing combination of contributing factors were non-shockable rhythm, low ETCO2, and metabolic derangement or duration of prehospital low flow time combined with low ETCO2. Survival to discharge was achieved in six patients (1.7%) in the no-ECPR group and 50 (23%) in the ECPR group.

Conclusions

In this large nationwide study of patients admitted for possible ECPR, 62% were not treated with ECPR. The most frequent reasons to abstain from ECPR were duration of prehospital low flow time, metabolic derangement, and low ETCO2.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): The Danish Heart Foundation

Mechanical circulatory support for refractory out-of-hospital cardiac arrest: a nationwide multicentre study

Background

Extracorporeal cardiopulmonary resuscitation (ECPR) has shown potential as a salvage therapy for patients with refractory out-of-hospital cardiac arrest (OHCA). Despite growing interest in and a growing body of literature on ECPR for refractory OHCA, robust evidence on patient eligibility is still lacking.

Purpose

To describe the survival, neurological outcome, and adherence to the national consensus with respect to use of ECPR for OHCA, and to identify factors associated with outcome.

Methods

Retrospective, observational cohort study of patients who underwent ECPR for OHCA at four cardiac arrest centres. Binary logistic regression and Kaplan-Meier survival curves were performed to assess association with 30-day mortality.

Results

A total of 259 patients receiving ECPR for OHCA between July 2011 and December 2020 were included in the study. Thirty-day survival was 26% and a good neurological outcome Cerebral Performance Category (CPC) 1–2 was observed in 94% of patients at discharge. Strict adherence to the national consensus showed a 30-day survival rate of 30%. Adding one or more of the following criteria to the national consensus: signs of life during cardiopulmonary resuscitation (CPR), pre-hospital low-flow <100 minutes, pH >6.8 and lactate <15 mmol/L increased the survival rate to 48%, but would exclude 58% of the survivors from the current cohort. Logistic regression identified initial presenting rhythm with asystole (RR 1.36, 95% CI 1.18–1.57), pulseless electrical activity (PEA) (RR 1.20, 95% CI 1.03–1.41), initial pH <6.8 (RR 1.28, 95% CI 1.12–1.46) and lactate levels >15 mmol/L (RR 1.16, 95% CI 1.16–1.53) as factors associated with increased risk of 30-day mortality. Patients presenting signs of life during CPR had threefold higher survival rate than patients without signs of life (45% versus 13%, p<0.001)

Conclusion

A high survival rate with a good neurological outcome was observed in this population of patients treated with ECPR for OHCA. Signs of life during CPR may aid the decision-making in the selection of appropriate candidates. Stringent patient selection for ECPR may produce higher survival rates but potentially withholds life-saving treatment in a significant proportion of survivors, why optimization of the selection criteria is still necessary.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): This work was supported by the Danish Heart Foundation [20-R142-A9498-22178]; and Health Research Foundation of Central Denmark Region [R64-A3178-B1349] Survival and adherence to consensusSigns of life during CPR