NOSOCOMIAL ENDOCARDITIS ON AORTIC BIOPROSTHESIS, A CASE OF ACCELERATED ATHEROSCLEROSIS

Abstract

Abstract Male, 79 years old, presented to the ED with chest pain and hemodynamically instability. Approximately one month prior, he underwent aortic bioprosthesis implantation for severe aortic stenosis. Pre–intervention coronary angiography revealed diffuse atheromatous plaques, none of which were stenotic. Additionally, the patient‘s medical history included paroxysmal atrial fibrillation on NOAC, hypertension and COPD. Upon admission: NIBP 80/50 mmHg, HR 150 bpm, and oxygen saturation was 85%. ECG showed atrial fibrillation with ST–segment elevation from V1 to V5. Arterial blood gas analysis revealed pH 7.25 and lactate 6 mmol/L. He received inotropic and vasopressor support, and prompt coronary angiography was performed, revealing 99% stenosis of the mid left anterior descending artery at the bifurcation with the diagonal branch, which was treated with angioplasty and coronary stent placement (Fig.1). Transthoracic echocardiography demonstrated the presence of the aortic bioprosthesis with diffusely thickened leaflets consistent with multiple vegetations. Transesophageal echocardiography confirmed a nosocomial infectious endocarditis, with mild–to–moderate stenosis, and evidence of peri–prosthetic echogenic material directed towards the left atrium, suggestive of abscess. The patient reported low–grade fever and asthenia in the weeks prior. The systemic and local inflammatory state of the endocarditis contributed to an accelerated atherosclerotic process, destabilizing the plaque and resulting in its rupture. Blood cultures identified multidrug–resistant Staphylococcus hemolyticus, for which specific antibiotic therapy was started. The patient and his family declined cardiac surgery due to high operative risk. Follow–up TEE, after approximately six weeks of intravenous antibiotic therapy, showed reduced vegetations on the bioprosthetic valve leaflets, with evolution of the previously noted large echolucent cavity, along with two similar peri–prosthetic lesions. These findings were confirmed on contrast–enhanced CT. The patient, achieving hemodynamic stability, was discharged home, continuing intravenous antibiotic therapy (OPAT protocol). At the one–month post–discharge follow–up, the patient was asymptomatic and hemodynamically stable. A repeat TEE showed normally mobile bioprosthetic valve leaflets without vegetations, and the previously noted large cavity with internal flow, consistent with cleansed abscess (Fig.2–3).