AN UNCOMMON CAUSE OF MECHANICAL PROSTHETIC VALVE OBSTRUCTION

Abstract An 84–years–old man presented to the ED for worsening exertional dyspnoea and fever. Medical history included CKD, hypertension, permanent AF, type 2 diabetes mellitus, chronic coronary syndrome with mild LV dysfunction. He previously underwent a revascularization with a CABG, an AVR with a 27mm mechanical prosthesis for a severe stenosis and an implantation of a CRTD. At admission, his vitals were as follows: BP 110/75, HR 77 (mean value) and SpO2 94% in room air. He was arrhytmyc but normofrequent; vesicular murmur was reduced in medio–basal right field, with presence of diffuse wet lung sounds. Lower limbs oedema was present. A CT scan detected a pneumonia and an antibiotic therapy was started. A TT echocardiography showed a moderate LV dysfunction due to diffuse hypokinesia, a moderate–to–severe MR and high prosthetic gradients (meanG 46mmHg) with a single element of the prosthetic valve in motion as for prosthetic obstruction. Laboratory exams and blood cultures were not consistent with endocarditis. A TOE confirmed that the mobility of the anterior prosthetic element was greatly reduced. No endocarditic vegetations were detected. A fluoroscopy and a focused CT study were performed: the aortic prosthesic valve anterior hemidisk was essentially immobile. The case was discussed with the Heart Team: due to the high surgical risk, any potential indication for surgery was excluded, hence unfractionated heparin was started in the suspicion of prosthetic thrombosis. Nonetheless, the prosthetic malfunctioning persisted at follow–up and a final diagnosis of obstruction from pannus was made. The patient was safely discharged with his usual anticoagulant therapy based on acenocoumarol. The following check–ups were unremarkable, with stable hemodynamic compensation. Acute heart failure due to prosthetic valve obstruction is a relatively infrequent cause of hospitalization, still it should be considered for the possible life–threatening hemodynamic consequences. The diagnosis is challenging: multimodality imaging is often necessary to differentiate between pannus and thrombus, but a definite diagnosis remains difficult to obtain.