Challenging Cases of Aortic Prosthesis Dysfunction, the Importance of Multimodality Imaging, a Case Series

ECG-gated multidetector computed tomography (MDCT) is a promising complementary technique for evaluation of cardiac native and prosthetic structures. MDCT is able to provide a broader coverage with faster scan acquisition times that yield higher spatial and temporal resolution for cardiac structures whose quality may be affected by artifacts on ultrasound. We report a case series about the most challenging complications occurring after prosthetic aortic valve implantation in four patients: pannus, paravalvular leak, prosthesis’ misfolding and subaortic membrane reformation. In all the cases, enhanced MDCT using a retrospective protocol provided accurate 3D morphoanatomic information about cardiac and extracardiac structures, improving and speeding up the correct diagnosis and treatment planning. Integrated imaging, in particular with MDCT, is now the present, and it will increasingly be the future in the assessment of cardiac structural pathology.

Comparative analysis of hemodynamic characteristics of the biological xenogenic pericardial prosthesis MEDINGE-BIO with “easy change” system and the xenogenic aortic prosthesis Hancock II after aortic valve replacement

Aim. To compare the outcomes of aortic valve replacement using the xenogenic aortic prosthesis Hancock II and the novel Russian xenogenic pericardial prosthesis MEDINGE-BIO.Material and methods. The study included patients operated on for aortic stenosis in the cardiac surgery department № 1 of the Cardiology Research Institute (Tomsk National Research Medical Center). All patients were divided into two groups. The first group included 54 patients with Hancock II prostheses, the second — 91 patients with MEDINGE-BIO prostheses. Hemodynamic characteristics of heart valves were assessed by echocardiography before surgery and before discharge (on average 10 days after surgery).Results. When comparing hemodynamic parameters before and after surgery, significant differences between the groups were not obtained. The average pressure gradient after surgery using Hancock II and MEDINGE-BIO prosthesis was 21,6±7,9 and 17,9±5,6 mm Hg, respectively (p=0,05).Conclusion. The comparative analysis showed that the novel biological prosthesis MEDINGE-BIO has comparable hemodynamic characteristics with the well-known aortic prosthesis Hancock II.

Abstract 14789: Multimodality Imaging in Mycobacterium Chimaera Cardiovascular Infections

Introduction: Mycobacterium Chimaera (MC) infections following cardiovascular surgery are challenging to diagnose given their insidious presentation. We therefore reviewed the various imaging modalities used to diagnose these infections at Mayo Clinic. Methods: Cases from 01/01/2010-06/01/2020 were identified using electronic medical records. Demographics and clinical history were collected. Imaging studies, including transthoracic echocardiogram (TTE), transesophageal echocardiogram (TEE), positron emission tomography / computed tomography (PET/CT), cardiac CT (CCT), and cardiac magnetic resonance (CMR) were reviewed. Results: A total of 7 patients (85.7% male) were found. 6 underwent aortic valve replacement and 1 received an aortic composite valve conduit. Surgical dates ranged from 01/2010-12/2018. Mean age at presentation was 63.3 years. Mean time from surgery to symptom onset was 28.0 months. All patients underwent TTE and TEE; prosthetic valve endocarditis was identified in 6 cases between both, while CMR established the diagnosis in 1 case. TTE showed prosthetic valve obstruction in 2 cases and an anterior pseudoaneurysm in 1 case. TEE findings included thickened prosthesis and/or vegetations (n=5), thickened posterior root (n=4), and root abscess (n=3). Among the 3 patients who underwent PET/CT, 2 demonstrated increased fluorodeoxyglucose (FDG) uptake around the aortic prosthesis; in addition, 1 had elevated FDG uptake in the myocardium suggesting myocarditis. 1 patient did not have aortic prosthesis FDG uptake. In the 2 patients who had CCT, 1 showed a pseudoaneurysm that prompted suspicion for endocarditis, and the other revealed a fluid collection adjacent to the aortic valve conduit. 2 patients underwent CMR; 1 had aortic prosthesis thickening and patchy areas of myocardial delayed enhancement suspicious for myocarditis, whereas the other showed vegetation and an aortic root abscess. Conclusion: TTE plus TEE successfully identified MC prosthetic valve endocarditis in most cases with TEE having higher specificity. Advanced imaging techniques are helpful to support the diagnosis and assess for myocardial and/or aortic involvement. Combining these modalities is therefore crucial in unveiling this elusive organism.