Funding Acknowledgements Type of funding sources: None. Introduction  Valvular aneurysm (VA) is a rare disease whose etiology most frequently includes infective endocarditis but also connective tissue or degenerative myxomatous diseases or traumatism related to a remote surgical procedure. Purpose: Our study aims to describe clinical and echocardiographic features of VA. Methods:  12 years retrospective observational study. Inclusion criteria: patients (pts) found to have a VA by echocardiography (E). A VA was defined as a saccular bulging or a cyst-like outpouching of a valve leaflet that expands and collapses during systole or diastole. The ability of different E techniques in imaging and sizing the valve aneurysm and clinical data were collected. Results: In a 12 years observational period, 12 pts (7 male, 5 female) with a mean age of 41 years ± 16.6 were found to have VA as diagnosed by two experienced readers. In 10 pts there was a diagnosis of IE according to the ESC, AHA criteria. In two pts IE work up was negative. In the patient with definite IE, blood cultures were reported as positive in 7/10 pts (staphylococci 4 pts, Pseudomonas 2 pts, clostridium difficile 1) and 9 pts out of 10 pts underwent surgery and 1 died; all of them had valve replacement except one had mitral valve (MV) repair. Severe regurgitation was found in 9 cases. Associated IE features were: perforation (11 pts), abscess (3pts), vegetation (7pts), fistula (1pt), and embolism (6 pts). Echo features are reported in table 1. Transthoracic E was able to image the VA in only 3/12 pts. Discussion: The spectrum of the VA in our cohort is very unusual. We reported a VA in a bioprosthesis MV not IE related and never described, one case of valvular aneurysm in a bicuspid aortic valve, and 2 cases in the posterior mitral leaflet (PML). The etiology of VA was related to IE as the leading cause (ten in our cohort). In the two pts where no IE was diagnosed, the possible pathogenesis in one patient may have been related to a remote surgical procedure (left atrial dissection) and in the second patient to degenerative phenomena of the MV bioprosthesis. Being the imaging uncommon, it is important to not misinterpret the VA features with large vegetations, cystic lesions, and abscess. Conclusion:  In our series, both the typical spectrum of the disease and less common presentations have been found. We reported one of the largest series of VA with never described unusual presentation. 2-dimensional (D) transesophageal E (TEE) was the key E modalities in the diagnosis integrated by 3D TEE allowing an anatomical imaging useful in surgical decision planning. Almost all cases were associated with perforation and severe regurgitation and a high incidence of embolism. All the cases with IE required surgery except one that died while medical therapy and follow up in the other etiologies . The unusual echocardiographic features have to be as early as possible detected in order to let the patient have the best therapeutical interventions. Abstract Table 1: Echocardiographic features  Abstract Figure. Valvular aneurysm imaging

A 63–year–old female known case of diabetes, hypertension, dyslipidemia and chronic kidney disease underwent mitral valve (MV) replacement because of severe regurgitation (RGT). Few weeks after, she was admitted due to decreased level of consciousness, drowsiness, abdominal distension and fever. Laboratory investigations showed positive blood cultures for Staphylococcus aureus and elevated inflammatory markers. Brain computed tomography (CT) revealed multiple infarcts due to systemic embolization. Transthoracic echocardiography (TTE) showed bioprosthesis (BP) leaflets coated by a mass causing significant obstruction (peak/mean=17/8 mmHg) with mild intravalvular RGT. Mild thickening of aortic valve (AV) cusps with mild RGT and moderate tricuspid RGT were also noted. Left and right ventricles were normal in size and function. A transesophageal echocardiography (TEE) (Figure 1) showed BP leaflets coated by a mass with a mobile vegetation attached on the atrial surface (10x9mm) causing severe obstruction and mild intravalvular RGT. A periaortic abscess, surrounding the left and the non–coronary cusps and involving the mitro–aortic fibrosa was also found. A fistula between the aortic root and the left atrium was detected by color Doppler and CW Doppler (systodiastolic high velocity shunt) (Figure 1). Further three dimensional (3D) analysis allowed to anatomically locate the position of the fistula which started close to the ostium the left coronary (LC) artery, passing through the mitroaortic fibrosa and opening anteriorly next to the strut of the BP (Figure 2). Contrast cardiac CT was advised but it was not performed to avoid further kidney impairment. The consensus was to perform redo–surgery. Therefore, the patient underwent MV cleaning of abscessual area, reconstruction of the aortic annulus with AV replacement. A coronary artery bypass surgery on LC artery was also necessary as the ostium was narrowed during the reconstruction of the area. Echocardiographic findings were confirmed at surgery. In our case 3DTEE accurately delineated cardiac anatomy and provided crucial anatomic details useful in the surgical planning. It is also important to highlight that the diagnosis may be challenging as the jet may be misinterpreted as mitral RGT. In this context, 3D imaging offers incremental value, as it is able to offer a clear view of the mitral valve.3DTEE was particularly helpful in our setting because the patient was at high risk to perform contrast study.