Unprovoked Submassive Saddle Pulmonary Embolism in an Adult Male After Pfizer COVID-19 Vaccination.

Pulmonary emboli (PEs) occur when the pulmonary artery is blocked by foreign material. In one such instance, this foreign material can be a blood clot that may occur from patient risk factors inducing a prothrombotic state. The relationship between COVID-19 vaccines and a prothrombotic state is novel and changing as our understanding of the relationship between the two evolves. The patient in this case study presented with unrelenting and progressive dyspnea, tachycardia, and unilateral lower extremity swelling two days after receiving the second dose of the Pfizer COVID-19 vaccine. After diagnostic testing, the patient was found to have a submassive saddle pulmonary embolism with subsequent right heart strain. This patient was treated with appropriate anticoagulation therapies, including heparin and apixaban, as well as thrombectomy, and made a complete recovery. The possible relationship between COVID-19 vaccines and thrombotic events supports the need for increased awareness of a potential new risk factor behind the development of PE. It is our hope that this case report will help raise awareness of an association despite the lack of incident data at this time.