Decellularization Following Fixation of Explanted Aortic Valves as a Strategy for Preserving Native Mechanical Properties and Function

Mechanical or biological aortic valves are incorporated in physical cardiac simulators for surgical training, educational purposes, and device testing. They suffer from limitations including either a lack of anatomical and biomechanical accuracy or a short lifespan, hence limiting the authentic hands-on learning experience. Medical schools utilize hearts from human cadavers for teaching and research, but these formaldehyde-fixed aortic valves contort and stiffen relative to native valves. Here, we compare a panel of different chemical treatment methods on explanted porcine aortic valves and evaluate the microscopic and macroscopic features of each treatment with a primary focus on mechanical function. A surfactant-based decellularization method after formaldehyde fixation is shown to have mechanical properties close to those of the native aortic valve. Valves treated in this method were integrated into a custom-built left heart cardiac simulator to test their hemodynamic performance. This decellularization, post-fixation technique produced aortic valves which have ultimate stress and elastic modulus in the range of the native leaflets. Decellularization of fixed valves reduced the valvular regurgitation by 60% compared to formaldehyde-fixed valves. This fixation method has implications for scenarios where the dynamic function of preserved valves is required, such as in surgical trainers or device test rigs.

RENAL DISEASE IN SYSTEMIC LUPUS ERYTHEMATOUS: ALL THAT GLITTERS IS NOT GOLD

Patients with systemic lupus erythematosus may occasionally develop renal pathology from causes unrelated to the underlying disease. We describe one such case. This 22-year-old lady, with past history of arthritis, presented with dyspnea and fever. She had clinical signs consistent with systemic lupus erythematosus. Echocardiogram revealed valvular regurgitation. Antibiotics were started for probable infective endocarditis. She developed acute kidney injury. This was initially attributed to lupus nephritis, but subsequently renal histopathology revealed acute interstitial nephritis. Renal functions normalized with oral prednisolone. This case highlights the fact that a broader differential diagnosis must always be considered even if the diagnosis is clear.

Association between Cardiac Auscultation and Echocardiographic Findings in Warmblood Horses

Heart murmurs are detected frequently when auscultating horses and certain murmurs can usually be linked to specific valvular regurgitations. Limited information exists about the accuracy of these broad rules in warmblood horses and the influence of grade of the regurgitation and dimensional changes on murmur intensity. This study aims to clarify the accuracy of cardiac auscultation in warmblood horses and the influence of the grade of regurgitation and dimensional changes on the loudness of the murmur. In this retrospective study, 822 warmblood horses presented for cardiac examination in a large equine referral center in northern Germany underwent a thorough cardiac auscultation. In total, 653 of these revealed one or more heart murmurs. Most common auscultatory findings were left-sided systolic murmurs (68%) or left-sided diastolic murmurs (15%). On 635 of these horses, an echocardiographic examination was performed, revealing regurgitations of the mitral valve as the most common valvular regurgitation (77%) followed by regurgitations of the aortic valve (23%). Thirty-one percent of horses that underwent echocardiographic examination displayed dimensional changes of one or more compartments of the heart, with the left atrium being most affected (21%), followed by the left ventricle (13%). The main goal of this study was to link certain auscultatory findings with results of the echocardiographic examinations, trying to determine whether auscultation and echocardiography agreed on the valve affected, as well as to find out if loudness of the murmur coincided with grade of regurgitation and presence of dimensional changes. Agreement between auscultation and cardiac ultrasound was substantial (Kappa 0.74) if one or more murmurs and regurgitations were present and almost perfect (Kappa 0.94) if only one murmur and one regurgitation were found. Auscultation was particularly well suited for detection of left-sided systolic and diastolic murmurs, with 87% of left-sided systolic murmurs being caused by a mitral valve regurgitation and 81% of left-sided diastolic murmurs originating from an aortic valve regurgitation. We found a fair agreement between the grade of regurgitation and the respective murmur. Association was particularly good between mild regurgitations and low-grade murmurs, while differentiation between moderate to severe regurgitation based upon the loudness of the murmur was less reliable. Dimensional changes were usually linked to more severe regurgitations and higher-grade murmurs. However, a direct correlation between murmur intensity and the presence or severity of dimensional changes, independent of the grade of valvular regurgitation, could not be established in this cohort of horses.

External or subcomissural annuloplasty in bicuspid aortic valve repair: which is better?

Patients with a bicuspid aortic valve (BAV) are at increased risk of valvular regurgitation compared to their counterparts with a tri-leaflet aortic valve. There is now increasing emphasis to offer BAV repair to mitigate the risks of prosthesis-related complications, including thromboembolism, haemorrhage and endocarditis, as well as structural valve deterioration and future re-operation with conventional valve replacement, particularly in younger populations. Furthermore, over the preceding two decades, our greater understanding of the functional anatomy of the BAV, pathophysiological mechanisms of BAV insufficiency and the development of a functional classification of aortic regurgitation have significantly contributed to the evolution of aortic valve reconstructive surgery. In this commentary, we discuss a recent article from the Journal of Cardiac Surgery comparing external annuloplasty and subcommissural annuloplasty as techniques for BAV repair.

689. Streptococcus suis Endocarditis: Echocardiographic Features and Clinical Outcomes

Background Streptococcus suis (S. suis) is a zoonotic pathogen that transmits to the human with direct contact of pig or raw pork ingestion. This infection has been described in Asia, especially Thailand, Vietnam, and China. S. suis could cause wide range of infection, including endocarditis. This study aimed to describe the clinical features, echocardiogram findings, and outcomes of S. suis endocarditis. Methods A single center, ten-year (January 2009 to December 2018), retrospective cohort was conducted among patients who were diagnosed with S.suis endocarditis in 1,200-bed hospital in Northern, Thailand. Results Forty-three patients of S.suis endocarditis were identified during the study period. Of those, 28 (65%) patients had positive blood culture and 15 (35%) was diagnosed by 16SRNA bacterial identification from heart valve tissue. Majority (81%) were male with median age of 35. There were 62 affected valves in 43 patients. Twenty patients (48%) had vegetation larger than 10 mm in diameter and 35 (81.4%) patients had moderately severe or severe valvular regurgitation. Valvular perforation was described in 23 patients (53%). Perivalvular complications were founded in 15 patients (35%). Systemic embolism occurred in 17 (40%) patients. Cardiac operation was undertaken in 35 (81%) patients. There were 2 in-hospital deaths (5%) and 6 patients (14%) had disabilities. Moderately severe/severe regurgitation, systemic embolism, and no cardiac operation were significantly associated with disability or death from univariate analysis. By logistic regression analysis, systemic embolism was the only risk factor for disability or death (OR = 12.6, 95% CI 1.3-123.5, p = 0.029). Presenting signs/symptoms, prediction score and laboratory data on admission Conclusion S. suis endocarditis had high rate of valvular damage with complications and resulting systemic embolism. Surgery is required in majority of the patients. Embolism was associated with disability or death. Disclosures All Authors: No reported disclosures

Association between cardiac pathology and outcomes of patients with COVID-19 using a hand-held ultrasound

Background The association between COVID-19 infection and the cardiovascular system has been well described. Strict precautions limit the use of formal echocardiography in this setting. Information on the importance of the utilization of a hand-held point-of-care cardiac ultrasound (POCCUS) for cardiac evaluation in these patients is scarce. Objective To investigate the utilization of hand-held echocardiography in COVID-19 hospitalized patients and the association between cardiac pathologies and outcomes. Methods Consecutive patients diagnosed with COVID-19 underwent POCCUS evaluation using a hand-held ultrasound within 24 hours of admission at our institute, throughout March-May 2020. According to the POCCUS results, the patients were divided into two groups: 'Normal' and 'Abnormal' (including left or right ventricular dysfunction or enlargement, or moderate/severe valvular regurgitation/stenosis). Results Among 102 patients, 26 (25.5%) had an abnormal POCCUS study. They were older, with more co-morbidities, cardiovascular disease history, chronic medical therapy, and more severe presenting symptoms, as compared to the group with a normal echocardiography exam. Individual and composite endpoints (advanced ventilatory support, acute decompensated heart failure, shock, or death) are presented in Table 1. Multivariate logistic regression analysis adjusting for pertinent variables revealed that abnormal echocardiography at presentation was independently associated with the composite endpoint OR=4.63 (95% CI 1.51–14.15, p=0.007). Conclusions Abnormal echocardiography results in COVID-19 infection settings are associated with a higher burden of medical comorbidities and independently predict major adverse endpoints. Hand-held POCCUS at presentation can be utilized as an important tool for risk stratification for hospitalized COVID-19 patients. FUNDunding Acknowledgement Type of funding sources: Private hospital(s). Main funding source(s): SZMC Scientific

Novel computed-tomography derived prognostic markers in patients undergoing TAVI with a self-expanding valve

Introduction Transcatheter aortic valve implantation is the treatment of choice in a consistently expanding group of patients with severe aortic valve stenosis. Tricuspid and mitral annular dilatation with consequent valvular regurgitation are associated with adverse outcome. Computed tomography angiography (CTA) is routinely performed for preprocedural evaluation of vascular access and prosthesis sizing. Purpose To evaluate the impact of mitral and tricuspid annular dimensions in preprocedural CTA on prognosis of patients undergoing TAVI with a self-expanding valve. Methods CTAs of consecutive patients undergoing TAVI in a single high-volume center between 2016 and 2019 were retrospectively evaluated. Maximal septolateral tricuspid annular diameters (TAD) and mitral annular diameters (MAD) were obtained and measured from properly angulated three dimensional CTA datasets. Moreover, maximal pulmonary artery diameter perpendicular to the long axis was measured in every patient. Patients were followed up by clinical visits or telephone contacts. As clinical events were defined all-cause mortality, stroke and heart failure hospitalization. Results In total 123 patients were included in the study. The mean follow-up duration was 875±383 days and 21 clinical events were recorded. There was a moderate but statistical significant correlation between TAD and both pulmonary artery diameter (r=0.39, p<0.001) and pulmonary artery systolic pressure by echocardiography (r=0.23, p=0.015). In univariate logistic regression analysis pulmonary artery diameter and TAD were both associated with heart failure hospitalization (p=0.03 and 0.02 respectively). In addition, MAD was associated with total events (OR: 0.43, 95% CI 0.19–0.99, p=0.048). The relationship of MAD with events remained significant after adjustment for sex, age and tricuspid annular dimensions (OR: 0.28, 95% CI 0.1–0.79, p=0.02). Conclusions TAD and MAD were associated with heart failure rehospitalization and clinical events respectively in patients undergoing TAVI with a self-expanding valve. Further larger prospective studies are warranted to evaluate the prognostic value of these CTA markers. FUNDunding Acknowledgement Type of funding sources: None.