Introduction: Chronic pulmonary hypertension (PH) can display acute elevations in pulmonary arterial pressure (PAP) in the setting of hypoxemia, pulmonary embolism (PE), and possibly sepsis. Case Description: A 68-year-old man with chronic obstructive pulmonary disease, heart failure, recent tobacco cessation, and recent 2-vessel coronary artery bypass grafting (CABG) presented with one to two weeks of respiratory symptoms and syncope on the day of admission. He was found to have a urinary tract infection and Escherichia coli bacteremia. Transthoracic echocardiography found a systolic PAP of 100-105 mmHg, increased from a mean PAP of 32 mmHg before CABG. PE was not seen on computed tomography angiography (CTA). Ventilation-perfusion scan two days later found evidence of subsegmental PE. PAP prior to discharge was 30-35 mmHg plus right atrial pressure. Conclusion: PAP can rise substantially in the acute or subacute setting, particularly when multiple disease processes are involved, and decrease to (near) baseline with proper therapy. Chronic PH may even be protective. In a complex clinical setting with multiple possible etiologies for elevated PAP, clinicians should have a high suspicion for PE despite a negative CTA.