Platelet dysfunction after Out of Hospital Cardiac Arrest. Results from POHCAR: A prospective observational, cohort
Agnieszka Skorko1, Andrew Mumford2, Matthew Thomas1
1Department of Anaesthesia, University Hospitals Bristol NHS Foundation Trust, Bristol, UK.
Insights
Out-of-hospital cardiac arrest (OHCA) patients showed reduced platelet activation but similar clot formation compared to ST-segment elevation myocardial infarction (STEMI) patients. Hyperfibrinolysis was common in both groups, without increased bleeding risk.
Area of Science:
- Cardiology
- Hematology
- Critical Care Medicine
Background:
- Patients experiencing out-of-hospital cardiac arrest (OHCA) may develop coagulopathies.
- Understanding coagulation and platelet function post-OHCA is crucial for guiding treatment strategies.
- Comparison with ST-segment elevation myocardial infarction (STEMI) patients undergoing percutaneous coronary intervention (PCI) provides a relevant clinical benchmark.
Purpose of the Study:
- To prospectively investigate coagulation and platelet function in OHCA patients upon admission.
- To compare these parameters with those of STEMI patients undergoing PCI.
- To assess the feasibility of near-patient testing for these parameters in an emergency setting.
Main Methods:
- Observational feasibility study involving 30 OHCA patients and 30 STEMI patients.
- Blood samples analyzed immediately on emergency department admission.
- Near-patient thromboelastometry and platelet function analyzer used.
- Physiological parameters, demographics, bleeding rates, and 30-day survival recorded.
Main Results:
- OHCA patients exhibited reduced platelet activation (thrombin receptor-stimulated activation) compared to STEMI patients (p=0.03).
- Maximum clot firmness time was prolonged in OHCA patients (p=0.01).
- Hyperfibrinolysis was prevalent in both groups (50% OHCA, 57% STEMI) but did not correlate with increased 30-day bleeding.
Conclusions:
- OHCA patients present with reduced thrombin receptor function but generally comparable clot formation dynamics to STEMI patients.
- No gross coagulopathy was identified in the studied OHCA cohort.
- Hyperfibrinolysis is a common finding post-OHCA and STEMI; this feasibility study will inform future research power calculations.
Aim:
Coagulation and platelet function following out of hospital cardiac arrest (OHCA) at admission to a UK cardiology centre were investigated prospectively in this observational feasibility study, and compared to that of patients receiving percutaneous coronary intervention (PCI) for ST segment elevation myocardial infarction (STEMI).
Method:
Blood samples taken immediately at emergency department admission from patients after OHCA of probable cardiac origin were analysed using near-patient thromboelastometry and a platelet function analyser. Physiological parameters, demographic information, bleeding rates and 30-day survival were recorded, and compared to that of patients undergoing PCI for STEMI.
Results:
Thirty patients were enrolled into each group. Platelet activation with thrombin receptor stimulation was reduced in OHCA patients compared to STEMI patients; mean TRAP AUC OHCA 79.3 (95% CI 63.7-94.9) vs STEMI 101.6 (95% CI 87.4-115.8), p = 0.03. The maximum clot firmness time was prolonged in the OHCA group compared to the STEMI group; 1718s (1545s-1906s) vs 1544s (1387s-1709s), p = 0.01. Other measures of clot formation and strength were comparable between groups. Hyperfibrinolysis (maximum lysis > = 15%) was common in both groups (57% in STEMI; 50% in OHCA) but did not increase 30-day bleeding risk.
Conclusion:
OHCA patients demonstrated reduced thrombin receptor function at hospital admission but overall clot formation dynamics comparable to STEMI patients, indicating no gross coagulopathy post OHCA in our cohort. Hyperfibrinolysis was common both post OHCA and after STEMI. The results of this small feasibility study cannot draw clinical conclusions but will inform power calculations for future studies.
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