Evolocumab-associated haemorrhagic pericarditis with cardiac tamponade: case report.

Background: Evolocumab, a fully humanized monoclonal antibody that inhibits proprotein convertase subtilisin/kexin Type 9 (PCSK9), is one of the most widely used lipid-lowering therapies for atherosclerotic cardiovascular disease. It is generally well tolerated, but immune-mediated inflammatory reactions may occur with monoclonal antibodies. Among common adverse effects associated with evolocumab, pericardial disease associated with PCSK9 inhibitors is extremely rare. Case summary: A man in his late 70s on evolocumab for 2 months presented to the hospital for atrial flutter and moderate pericardial effusion. He was treated with amiodarone and discharged with colchicine and indomethacin. Ten days later, the patient represented with worsening shortness of breath, malaise, and jugular venous distension with echocardiographic evidence of tamponade physiology. Emergent pericardiocentesis drained about 1 L of sanguineous fluid. Autoimmune, infectious, and malignant aetiologies were systematically excluded. Evolocumab was discontinued, and the patient remained asymptomatic without recurrence. Discussion: This case illustrates a probable immune-mediated pericarditis with haemorrhagic effusion and tamponade seen with evolocumab use. Clinicians should remain vigilant for this rare monoclonal antibody-associated pericardial inflammation as a potentially serious adverse reaction to evolocumab, particularly when other common causes have been excluded. Continued pharmacovigilance is essential as the use of PCSK9 inhibitors expands.