- active bleeding - acute myocardial infarction or history of myocardial infarction within the past 3 weeks or cardiac arrest during hospitalization - hemodynamic instability with noradrenaline >0.2mcg/kg/min - acute renal failure requiring dialysis - liver failure (escalating liver failure with total bilirubin > 3 mg/dl) - suspicion of cirrhosis due to history of cirrhosis diagnosis, hepatic encephalopathy, documentation of portal hypertension, bleeding from esophageal varices, ascites, imaging or operative finding suggestive of liver cirrhosis, or constellation of abnormal laboratory test results suggestive of depressed hepatic function - cardiac tamponade - bacterial endocarditis - severe uncontrolled hypertension defined as sbp>185mmhg or dbp>110mmhg - cva (stroke), history of severe head injury within prior 3 months, or prior history of intracranial hemorrhage - seizure during pre-hospital course or during hospitalization for covid-19 - diagnosis of brain tumor, arterio-venous malformation (avm) or ruptured aneurysm - currently on ecmo - major surgery or major trauma within the past 2 weeks - gi or gu bleed within the past 3 weeks - known bleeding disorder - p2y12 receptor inhibitor medication (anti-platelet) within 5 days of enrollment - arterial puncture at a non-compressible site within the past 7 days - lumbar puncture within past 7 days - pregnancy - inr > 1.7 (with or without concurrent use of warfarin) - platelet count < 100 x 109/l or history of hitt - fibrinogen < 300mg/dl - known abdominal or thoracic aneurysm - history of cns malignancy or cns metastasis within past 5 years - history of non-cns malignancy within the past 5 years that commonly metastasizes to the brain (lung, breast, melanoma) - prisoner status

- active bleeding - acute myocardial infarction or history of myocardial infarction within the past 3 weeks or cardiac arrest during hospitalization - hemodynamic instability with noradrenaline >0.2mcg/kg/min - acute renal failure requiring dialysis - liver failure (escalating liver failure with total bilirubin > 3 mg/dl) - suspicion of cirrhosis due to history of cirrhosis diagnosis, hepatic encephalopathy, documentation of portal hypertension, bleeding from esophageal varices, ascites, imaging or operative finding suggestive of liver cirrhosis, or constellation of abnormal laboratory test results suggestive of depressed hepatic function - cardiac tamponade - bacterial endocarditis - severe uncontrolled hypertension defined as sbp>185mmhg or dbp>110mmhg - cva (stroke), history of severe head injury within prior 3 months, or prior history of intracranial hemorrhage - seizure during pre-hospital course or during hospitalization for covid-19 - diagnosis of brain tumor, arterio-venous malformation (avm) or ruptured aneurysm - currently on ecmo - major surgery or major trauma within the past 2 weeks - gi or gu bleed within the past 3 weeks - known bleeding disorder - p2y12 receptor inhibitor medication (anti-platelet) within 5 days of enrollment - arterial puncture at a non-compressible site within the past 7 days - lumbar puncture within past 7 days - pregnancy - inr > 1.7 (with or without concurrent use of warfarin) - platelet count < 100 x 109/l or history of hitt - fibrinogen < 300mg/dl - known abdominal or thoracic aneurysm - history of cns malignancy or cns metastasis within past 5 years - history of non-cns malignancy within the past 5 years that commonly metastasizes to the brain (lung, breast, melanoma) - prisoner status