question: Introduction:Venous thromboembolism (VTE) is a leading cause of morbidity and mortality worldwide, with an annual incidence of 1 to 2 per 1000 per year in the US. Data support that this incidence is often secondary to thromboprophylaxis failure more than omission. Studies have demonstrated that an extensive pro-inflammatory and hypercoagulable state is present in COVID-19 patients, however the duration of this state post-infection is unclear. Early identification of additional risk factors for thromboprophylaxis failure warrants a closer follow up.Case Description:A 47-year-old man with obesity, recent COVID-19 pneumonia with ventilator dependent respiratory failure (VDRF) presents with one-day history of worsening abdominal pain and bloating due to pneumoperitoneum secondary to PEG tube placement 9 days prior. Patient was discharged after a prolonged admission for management of respiratory failure in the setting of COVID-19 infection that was complicated with severe hemodynamic compromising, subsequently managed with mechanical ventilation and V-V ECMO. Patient received DVT prophylaxis since admission. On presentation, patient was tachycardic in moderate respiratory distress and SpO2 of 94% on 75% FiO2. Further work-up revealed COVID PCR negative, elevated Ferritin of 1130 ng/mL, elevated NT-proB type Natriuretic peptide (NT-Pro BNP) of 467 pg/mL and elevated D-Dimer of 914 ng/mL. ABG revealed decreased PO2 and elevated A-a gradient. Computed tomography angiogram revealed moderate sized right upper lobe pulmonary embolism with no evidence of right heart strain. Patient was started on heparin drip.Discussion:The development of VTE despite prophylaxis is not uncommon. The rates of DVT in the absence of prophylaxis range between 40 and 60% and 2-5% in its presence. It is pertinent learning to identify high risk patients to develop VTE and consider anticoagulation at a higher dose or for a longer period of time even after discharge. Patients with COVID-19 infection possess and additional risk from the underlying hypercoagulable state and a worse outcome is expected. The high risk of thrombosis in COVID-19 is demonstrated by the increase in d-dimer, which was found to be the most significant change in coagulation parameters in these group, suggesting increased thrombin production and activation of fibrinolysis. There is therefore a need to identify the increased risk of VTE at an early stage and to prevent thrombotic events and organ damage as far as possible. More data is needed on how long this hypercoagulability period persist, but definite steps need to be taken to address this common complication in this special population.