An Unusual Case of Pannus Formation - A Late Postoperative Complication of a Prosthetic Valve Replacement Causing Severe Cardiomyopathy

Abstract

There are several well-known long-term complications following prosthetic valve replacement. Pannus formation is one of the rare complications whose estimated incidence varies between 0.3% and 1.3% per patient-year [1]. The exact etiology of pannus formation is unknown but histopathologically, pannus formation is due to fibroelastic hyperplasia that variably occurs after valve implantation [2]. The rarity and acute coronary syndrome like clinical presentation makes pannus formation a clinically important diagnosis during initial presentation. Workup preferably includes Transthoracic Echocardiography (TEE) with or without CT angiography. Management includes urgent or emergent surgical excision of the pannus with or without re-replacement of the aortic valve [1]. We present a 66-year-old female who presented with typical angina symptoms along with diffuse ischemic EKG changes five years after aortic valve replacement surgery with Trifecta Bioprosthesis due to severe aortic stenosis with Non-ST Elevation Myocardial Infarction (NSTEMI). Coronary angiography done on admission showed left main ostial stenosis of 90-95 % in proximity to the aortic valve prosthesis. A Transthoracic Echocardiogram (TTE) revealed an ejection fraction of 30-35 % with global hypokinesia but did not suggest any valve dysfunction. CT angiogram was done the next day which revealed a noncalcified plaque (pannus) greater than 75% occlusion in the left main in proximity of the aortic valve. Despite expedited care and surgical evaluation, unfortunately the patient decompensated in the surgical operating room and did not survive.