Aneurysms of the aortic root and ascending aorta often require surgical correction. Currently, two common alternatives exist: The Bentall procedure has traditionally been used successfully for many decades, utilising an aortic valve prosthesis to replace the aortic valve and a conduit to replace the aneurysmic aorta. The more recent approach has been to reimplant suitable aortic valves utilising a dacron graft as well as replacing the affected aortic segment. The most widely used technique thereof is the David procedure. The decision for either operation depends greatly on patient circumstance and preference, as well as the recommendation of the operating surgeon. This is due to the associated features and disadvantages of the procedures at hand that make the careful choice of technique vital. Previous research has shown promising results for the equivalence, if not superiority, of the David procedure in certain patient groups, as well as in comparison to the Bentall procedure overall. At the same time, there are concerns about the David approach regarding the durability, perioperative risk, and long-term outcomes, among others. Regardless, avoidance of anticoagulation postoperatively has made it an attractive choice for patients who do not want to or cannot receive anticoagulants. While the David procedure has shown these beneficial properties, it has been widely limited to cases where the aortic valve is deemed suitable. Over the last decade, several studies have assessed the usage of David procedure for cases that did not previously seem to be a fit, such as patients with bicuspid aortic valves, who are now deemed suitable. With the David procedure becoming more widely applied and the application of the operation being extended, the question arises, whether the Bentall procedure remains the gold standard for correction of aortic root pathology. Several studies have been conducted over the years, but because cases are comparatively few, evidence is still lacking. For this, we conducted a study into the short and long-term outcomes of patients who underwent either Bentall or David procedures at the Leipzig Heart Centre between 2000 and 2015. Pre-operative, operative and post-operative data was gathered, and a follow-up was conducted through questionnaires, reports by physicians and telephone surveys. Statistical analysis was performed to gain data on perioperative mortality, adverse outcomes and long-term effects, such as bleeding incidents, reoperation rates and overall mortality, among others. This resulted in two publications that form the basis of this dissertation: Publication A sought to compare the outcomes of David cases with those who received correction with the Bentall procedure, including both mechanical valve prostheses and biological replacements. Publication B compared David cases to biological Bentall replacements. This subgroup analysis was done because both procedures avoid long term-anticoagulation. We found that both the David and Bentall operation had excellent early and long-term results, with comparable outcomes for early and late mortality among others. Furthermore, we did not see an increased risk of reoperation for the David procedure during our observational period. We recorded a higher incidence of serious bleeding events in the Bentall group (Publication A). The comparison of bioprosthetic Bentall cases to the David group showed equivalent outcomes for both procedures without significant difference in endpoints. While patient preferences and circumstances should still be considered, our investigations showed clear advantages for the David procedure in the analysed patient group. We concluded that the David operation is the preferable operation in patients with appropriate pathoanatomy, because long-term complications associated with prosthetic heart valves remain a major concern and it has shown to mitigate said complications.

Transcatheter aortic valve replacement in the setting of failed surgical bioprosthesis (valve-in-valve) is a valuable option for patients with bioprosthetic aortic stenosis or regurgitation who are deemed high risk for repeat open heart surgery. Although the procedure is successful with proper preprocedural assessment, instances of left main (LM) coronary artery ostium obstruction have been documented. We present a case of LM coronary obstruction in the immediate postoperative period following implantation of a 20-mm Edwards Sapien 3 valve inside the degenerated 21-mm Mitroflow bioprosthesis stenosis, which was treated with double stenting alongside the Edwards Sapien 3 valve creating a channel (“neo left main”) that extended from mid-LM to the upper margin of the Edwards Sapien 3 valve. Although valve-in-valve in a Mitroflow degenerated bioprosthesis is a relatively safe procedure, 2 or more stents may be necessary to scaffold a channel to the coronary arteries between Edwards Sapien 3 prosthesis and aorta in the event of a coronary obstruction.

<div><div><div><p>The aorta has many complex features including valve and vessel wall geometry, blood flow, and wall composition. Diseases such as aortic aneurysms and aortic valve lesions affect vessel function and may even lead to rupture, which can be fatal. However, current clinical diagnoses of aortopathies mainly rely on simple parameters such as diameter and growth rate. To better understand aortopathies and ultimately improve patient diagnoses and treatments, it is important to investigate disease progression as well as the effect of vessel wall composition changes and hemodynamic forces on aortic biomechanics, such as strain and wall shear stress distribution. Preclinical research using small animals allows for disease progression to be studied while controlling outside factors. The next important step is to apply the methods used in the preclinical studies to human patient data. Both preclinical and clinical studies often focus on noninvasive, patient-specific methods for further characterizing the biomechanics of the aorta using advanced techniques such as 4D flow magnetic resonance imaging, 4D ultrasound, computational fluid dynamics (CFD), and fluid structure interaction (FSI) modeling. Yet the challenge of bridging these research techniques to a clinical setting remains. Factors such as financial costs, acquisition time, and ease of analysis must be considered. Therefore, the following document highlights two specific aims to extend our knowledge about the effects of aneurysms and aortic valve lesions. We will 1) characterize the regional effects of murine abdominal aortic aneurysms on strain over time, and 2) use CFD and FSI to simulate the hemodynamic effects on the thoracic aorta using both murine and human patient imaging data. Conducting research using clinically translatable methods of biomechanical characterization that consider the complexity of the aorta on a patient-specific basis will contribute to our understanding and lead to better patient outcomes.</p></div></div></div>

Objective: Studies have shown that iodinated radiocontrast use is associated with acute renal failure especially in the presence of chronic kidney disease and multiple factors modulate this risk. The purpose of this meta-analysis is to compare the incidence of renal failure requiring hemodialysis between transfemoral (TF) and transapical (TA) transcatheter aortic valve replacement using the Edwards valve. Methods: The PubMed database was searched from January 2000 through December 2014. A total of 10 studies (n = 2,459) comparing TF (n = 1,268) and TA (n = 1,191) TAVR procedures using the Edwards valve were included. Variables of interest were baseline logistic EuroSCORE, prevalence of diabetes mellitus, hypertension, peripheral arterial disease, chronic kidney disease and amount of contrast used. The primary endpoint was incidence of renal failure requiring hemodialysis. The odds ratio and 95% CI were computed and P < 0.05 was considered as the level of significance. Results: The logistic EuroSCORE was significantly higher in TA compared to TF (P = 0.001) TAVR. The amount of contrast (mL) used was significantly higher in the TF group compared to the TA group (mean difference: 36.9, CI: 25.7-48.1, P < 0.001). The incidence of hemodialysis following the procedure was significantly higher in the TA group compared to TF group (odds ratio = 4.3, CI: 2.4-7.8, P < 0.00001). Conclusions: This meta-analysis suggests that despite the lower amount of contrast used in TA-TAVR, the incidence of renal failure requiring hemodialysis was higher with the Edwards valve. This suggests that the incidence of renal failure requiring hemodialysis after TAVR is associated with baseline comorbidities in the TA-TAVR group rather than the volume of contrast used.

Objectives: In patients with severe aortic stenosis who are at high risk for surgery, transcatheter aortic valve replacement (TAVR) has emerged as an alternative procedure using EV or CV. The objective of this meta-analysis is to compare 1-year mortality and major adverse cardiovascular and cerebrovascular events (MACCE) between Edwards valve (EV) and Medtronic CoreValve (CV). Methods: PubMed and the Cochrane Center Register of Controlled Trials were searched through December 2014. Twenty seven studies (n = 12,249) comparing TAVR procedure that used EV (n = 5745) and CV (n = 6504) were included. End points were procedural success rates, post-procedural mortality, myocardial infarction (MI), stroke, major bleeding, major vascular complications, incidence of new permanent pacemaker (PPM) placement and new left bundle branch block (LBBB). The odds ratio (OR) with 95% confidence interval (CI) was computed and p < 0.05 was considered for significance. Results: There were no significant differences between EV and CV for post-procedural in-hospital, 30-day and 1-year all-cause mortality rates (p = 0.53, 0.33 and 0.94 respectively), cardiovascular mortality (p = 0.61), stroke (p = 0.54), major bleeding (p = 0.25) and major vascular complications (p = 0.27). MI was significantly lower with EV compared to CV (OR: 0.56, CI: 0.35-0.89, p = 0.01). Placement of new PPM and new onset LBBB were significantly higher in CV compared to EV (OR: 3.35, CI: 2.96-3.79, p < 0.00001 and OR: 6.55, CI: 4.76-9.03, p < 0.00001 respectively). Conclusions: The results of our meta-analysis suggest that TAVR procedure using CV may be associated with a higher incidence of MI, new PPM placement, and new onset LBBB compared to EV. However, the type of valve placed does not affect mortality.

Background: Chronic aortic regurgitation (AR) patients demonstrate left ventricular (LV) remodeling with increased LV mass and volume but may have a preserved LV ejection fraction (EF). We hypothesize that in chronic AR, global longitudinal systolic and diastolic function will be reduced despite a preserved LV EF. Methods: We studied with Doppler echocardiography 27 normal subjects, 87 patients with chronic AR with a LV EF > 50% (AR + PEF), 66 patients with an EF < 50% [AR + reduced LV ejection fraction (REF)] and 82 patients with hypertensive heart disease. LV volume, transmitral spectral and tissue Doppler were obtained. Myocardial velocities and their timing and longitudinal strain of the proximal and mid wall of each of the 3 apical views were obtained. Results: As compared to normals, global longitudinal strain was reduced in AR + PEF (13.8 ± 4.0%) and AR + REF (11.4 ±4.7%) vs. normals (18.4 ± 3.6%, both p < 0.001). As an additional comparison group for AR + PEF, global longitudinal strain was reduced as compared to patients with hypertensive heart disease (p = 0.032). The average peak diastolic annular velocity (e’) was decreased in AR + PEF (6.9 ± 3.3 cm/s vs. 13.4 ± 2.6 cm/s, p < 0.001) and AR + REF (4.8 ± 2.1 cm/s, p < 0.001). Peak rapid filling velocity/e’ (E/e’) was increased in both AR + PEF (14.4 ± 6.2 vs. 6.2 ± 1.3, p < 0.001) and AR + REF (18.8 ± 6.4, p <0.001 vs. normals). Independent correlates of global longitudinal strain (r = 0.6416, p < 0.001) included EF (p < 0.0001), E/e’ (p < 0.0001), and tricuspid regurgitation velocity (p = 0.0176). Conclusion: With chronic AR, there is impaired longitudinal function despite preserved EF. Moreover, global longitudinal strain was well correlated with noninvasive estimated LV filling pressures and pulmonary systolic arterial pressures.

No description available.

PhD Thesis / Cardiac surgeons rely on simulation training to improve their surgical skills. The focus of this research was on creating a 3D aortic valve model for cardiac surgical skills training. The research was divided into four different stages including CAD model development, tissue testing using surgical tools, aortic valve model manufacturing and model evaluation. First, the development of a patient-specific aortic valve model was carried out. The process involved heavily processing CT scanned data of the aortic valve to extract the geometric information via segmentation. Patient-specific models are critical for pre-operative planning and training. However, those models are not ideal for large volume quantities due to the high production costs and the extensive manual labour required to process the models. Therefore, another approach was chosen to produce a generic model that was more suitable for large volume quantities. The generic aortic valve model was developed using data obtained from the literature. The contribution in this stage was developing the methodology to reverse engineer patient-specific cardiac tissues. Additionally, a generic CAD model of the aortic valve was developed. Second, to select suitable materials for the model, samples from biological tissues and polymers were tested using a surgical tool. The contribution in this stage was documenting the forces and displacements obtained from puncturing and cutting the samples using suturing needles and scalpel blades. Third, the aortic valve model was manufactured using two approaches including AM and casting. The contribution in this stage revolved around the development of several moulds for casting. Finally, evaluation of the model was done via an initial assessment session with surgical residents. Although the model was not evaluated in extensive training sessions, a plan highlighting the important elements to do that was included in this research. Thus, the contribution in this stage was developing the model testing plan. / Thesis / Doctor of Philosophy (PhD) / Typically, surgeons use post-mortem human tissues (cadavers) and animal tissues for surgical skills training. However, those methods can be both expensive and limited in availability. Therefore, other non-biological methods are introduced constantly to provide viable alternatives. Those methods include producing models using 3D printing, virtual reality (VR) simulation and even using household items to create training models. However, to date, there is a lack of highly accurate representation of real tissues (fidelity) of most models for cardiac surgical training. The purpose of this research was to develop and manufacture surgical skill training tools for cardiac surgeons focusing on the aortic valve cardiac tissues. The research was divided into several parts including developing computer models using patient-specific medical imaging, developing a general training model and training models manufacturing. Also, the research included manufacturing materials selection process as well as plans for testing the training models in training sessions.

Background: Infective endocarditis is a rare but severe condition associated with a high mortality rate in small animal patients. This condition is caused by a microbial (most often bacterial) infection of the valvular portion of the endocardium, from which proliferative and/or erosive lesions on the cardiac valves or immediately adjacent structures develop. The two most commonly affected cardiac valves are the aortic and mitral valves. Case presentation: We report the clinical case of a 4-year old male neutered Bull terrier, 27.6 kg, body condition score 4/9, that presented with a 3-months history of pyrexia and general weakness. The patient history also revealed a transient left hind limb lameness (grade 2/4), which coincided with the onset of clinical signs about 3 months before presentation. On physical examination, a left-sided systolic heart murmur (grade 3/6) with the same intensity at the left heart base and apex, and an irregularly irregular heart rhythm were noted. Electrocardiography showed ventricular premature complexes, and echocardiography revealed lesions consistent with endocarditis involving the aortic and mitral valve. Bacterial culture of blood yielded a positive result, and the organism isolated was identified as Erysipelothrix rhusiopathiae. The extended patient history revealed that the dog lived close to a farm housing pigs and other livestock. Conclusion: We report a rare case of the premortal diagnosis of infective bacterial endocarditis in a dog due to E. rhusiopathiae infection. Most reports about this condition are from necropsy series. This clinical case report emphasizes that E. rhusiopathiae infection and bacteremia should be considered as a differential diagnosis in dogs with suspected infective endocarditis, especially in dogs living in rural areas with access to livestock and particularly farm pigs. Also, particular emphasis should be placed on the zoonotic potential of this infectious disease.

No description available.