Abstract 2223: Shear Induced Platelet Function Is Highly Increased In Patients With Cardiac Arrest Undergoing Cardio-pulmonary Resuscitation (CPR)
Background: The prognosis of patients with cardiac arrest is still poor, and hardly any specific therapeutic options exist to improve outcome. Platelet activation has been observed in patients undergoing cardiopulmonary resuscitation (CPR). This may contribute to impairment of microcirculatory function and overall poor outcome despite return of spontaneous circulation. Data on direct platelet function in cardiac arrest are scarce. Platelets of patients with myocardial infarction are hyperfunctional, which predicts the degree of myocardial necrosis. Thus, we hypothesized that platelets may be even more hyper-functional in patients whose myocardial infarction causes cardiac arrest. We determined platelet function under high shear rates of patients with cardiac arrest and were further interested whether this may be related to the cause of cardiac arrest.
Methods: We conducted a prospective study in 77 cardiac arrest patients at the Emergency Department of a tertiary care hospital. Collagen adenosine diphosphate closure time (CADP-CT) was assessed by the FDA-approved platelet function analyzer (PFA-100). In addition, plasma levels of von Willebrand factor (vWf:RiCo) were measured by turbidometry. Independent staff members of the emergency department not otherwise involved in this trial diagnosed the origin of cardiac arrest.
Results: More than half of cardiac arrests were caused by myocardial ischemia. CADP-CT values (54s; 95%CI: 48–60s in 3.8% citrate) were much shorter in these patients as compared to patients with other causes of cardiac arrest (110s; 95%CI: 84–135s, p<0.001). This is substantially less than the 87s (95%CI: 80–94s) in patients with ST-elevation myocardial infarction as previously published. vWf:RiCo levels were substantially increased above the upper normal limit (180 U/dL) in all patient groups.
Conclusion: Patients with myocardial ischemia triggered cardiac arrest displayed the highest degree of platelet hyper-function under high shear rates, which was not solely due to increased vWF. Those patients may benefit from a rapid, more aggressive anti-platelet therapy than currently performed or an anti-vWF targeted therapy.