ST-Elevation Myocardial Infarction in COVID-19: Redefining Anticoagulation Guidelines - Is Full Dose Anticoagulation Indicated in High Risk Patients to Prevent Thrombotic Coronary Artery Disease?

Introduction - Coronavirus disease 2019 (COVID 19) has direct and indirect effects on cardiovascular system which may be due to myocardial injury from hemodynamic derangement or hypoxemia, inflammatory myocarditis, stress cardiomyopathy, microvascular dysfunction /thrombosis due to hypercoagulability, or cytokine storm causing destabilization of coronary artery plaques. The vascular impact will be greater in patients who have preexisting CAD. Here, we report a patient with COVID 19 disease with significant coronary artery disease (CAD) who developed acute STEMI in spite of prophylactic dose anticoagulation. Case Description - A 67 year old male with significant CAD s/p CABG X 5 and PCI with 18 stents, DM II, HTN presented with dyspnea, fever and non productive cough. He tested positive for Covid19 and found to have bilateral infiltrates on chest X ray and elevated inflammatory markers. Patient was hypoxic requiring 80 % High-flow nasal oxygen supplementation. His D dimer levels on admission was normal around 250 and his serial D dimer were in range of 250-310, with no evidence of venous thromboembolism on ultrasound of lower extremities. He was started on prophylactic anticoagulation with enoxaparin. On Day 9, patient was found to have apical and anterior STEMI. Cardiac catheterization demonstrated significant thrombus burden with occluded left internal mammary artery to left anterior descending, occluded sephanous vein graft, occluded left anterior descending artery, occluded right coronary artery and left main with 90% occlusion. Percutaneous coronary intervention was deemed futile and not attempted in presence of mixed, refractory shock and profound respiratory failure. Patient died shortly thereafter. Discussion - Our patient developed severe acute coronary artery thrombosis in spite of prophylactic enoxaparin. The American Society of Hematology and CHEST guidelines suggests using prophylactic-intensity over intermediate or therapeutic anticoagulation in patients with COVID19 who do not have suspected or confirmed venous thromboembolism (VTE). Our case highlights the fact that in COVID 19 affected patients with significant CAD, therapeutic anticoagulation should be seriously considered in spite of absence of randomized evidence and a normal D dimer doesn't necessarily preclude this risk.