The heterotopic heart transplantation in mice as a small animal model to study mechanical unloading - Establishment of the procedure, perioperative management and postoperative scoring.

BACKGROUND: Unloading of failing hearts by left ventricular assist devices induces an extensive cardiac remodeling which may lead to a reversal of the initial phenotype-or to its deterioration. The mechanisms underlying these processes are unclear. HYPOTHESIS: Heterotopic heart transplantion (hHTX) is an accepted model for the study of mechanical unloading in rodents. The wide variety of genetically modified strains in mice provides an unique opportunity to examine remodeling pathways. However, the procedure is technically demanding and has not been extensively used in this area. To support investigators adopting this method, we present our experience establishing the abdominal hHTX in mice and describe refinements to the technique. METHODS: In this model, the transplanted heart is vascularised but implanted in series, and therefore does not contribute to systemic circulation and results in a complete mechanical unloading of the donor heart. Training followed a systematic program using a combination of literature, video tutorials, cadaveric training, direct observation and training in live animals. RESULTS: Successful transplantation was defined as a recipient surviving > 24 hours with a palpable, beating apex in the transplanted heart and was achieved after 20 transplants in live animals. A success rate of 90% was reached after 60 transplants. Operative time was shown to decrease in correlation with increasing number of procedures from 200 minutes to 45 minutes after 60 operations. Cold/warm ischemia time improved from 45/100 to 10/20 minutes. Key factors for success and trouble shootings were identified. CONCLUSION: Abdominal hHTX in the mouse may enable future examination of specific pathways in unloading induced myocardial remodeling. Establishment of the technique, however, is challenging. Structured training programs utilising a variety of training methods can help to expedite the process. Postoperative management, including daily scoring increases animal wellbeing and helps to predict survival.

Stentless vs. stented bioprosthesis for aortic valve replacement: A case matched comparison of long-term follow-up and subgroup analysis of patients with native valve endocarditis.

BACKGROUND: Current retrospective evidence suggests similar clinical and superior hemodynamic outcomes of the Sorin Freedom Solo stentless aortic valve (SFS) (LivaNova PLC, London, UK) compared to the Carpentier Edwards Perimount stented aortic valve (CEP) (Edwards Lifesciences Inc., Irvine, California, USA). To date, no reports exist describing case-matched long-term outcomes and analysis for treatment of native valve endocarditis (NVE). METHODS: From 2004 through 2014, 77 consecutive patients (study group, 59.7% male, 68.9 ± 12.5 years, logEuroSCORE II 7.6 ± 12.3%) received surgical aortic valve replacement (SAVR) with the SFS. A control group of patients after SAVR with the CEP was retrieved from our database and matched to the study group regarding 15 parameters including preoperative endocarditis. Acute perioperative outcomes and follow-up data (mean follow-up time 48.7±29.8 months, 95% complete) were retrospectively analyzed. RESULTS: No differences in early mortality occurred during 30-day follow up (3/77; 3.9% vs. 4/77; 5.2%; p = 0.699). Echocardiographic findings revealed lower postprocedural transvalvular pressure gradients (max. 17.0 ± 8.2 vs. 24.5 ± 9.2 mmHg, p< 0.001/ mean pressure of 8.4 ± 4.1 vs. 13.1 ± 5.9 mmHg, p< 0.001) in the SFS group. Structural valve degeneration (SVD) (5.2% vs. 0%; p = 0.04) and valve explantation due to SVD or prosthetic valve endocarditis (PVE) (9.1% vs. 1.3%; p = 0.04) was more frequent in the SFS group. All-cause mortality during follow-up was 20.8% vs. 14.3% (p = 0.397). When patients were divided into subgroups of NVE and respective utilized bioprosthesis, the SFS presented impaired outcomes regarding mortality in NVE cases (p = 0.031). CONCLUSIONS: The hemodynamic superiority of the SFS was confirmed in this comparison. However, clinical outcomes in terms of SVD and PVE rates, as well as survival after NVE, were inferior in this study. Therefore, we are reluctant to recommend utilization of the SFS for treatment of NVE.

Acute Pulmonary Artery Obstruction as the Primary Manifestation of a Rapidly Growing Intimal Sarcoma in a 54-Year-Old Patient.

Pulmonary artery sarcoma is a rare malignant neoplasm that is often misdiagnosed and most often only recognized postmortem during the autopsy. We present the case of a male patient with a rapidly progressive pulmonary tumor who underwent urgent pneumonectomy for increasing symptoms of chest pain and septic clinical picture. Histological analysis revealed the diagnosis of a pulmonary artery sarcoma. Despite an R1-resection and adjuvant chemotherapy, the patient is in good clinical health and free of tumor relapse 1 year after the surgery.

A matched pairs analysis of non-rib-spreading, fully endoscopic, mini-incision technique versus conventional mini-thoracotomy for mitral valve repair.

OBJECTIVES: Advances in video-assistance lead to an increase in minimal access mitral valve surgery (MAMVS) with decreased incision size yet maintaining the same quality of surgery. Further reduction in surgical trauma and at the same time improved visual guidance can be achieved by a non-rib-spreading fully 3D endoscopic technique (NRS-3D). We compared patients who underwent MAMVS either through an NRS fully 3D endoscopic or rib-spreading (RS) access in a retrospective matched-pair analysis. METHODS: A matched pairs analysis was undertaken of retrospectively collected data of 284 consecutive patients having received an MAMVS between January 2011 and May 2015. Fifty patients with an RS procedure were compared with 50 patients with an NRS fully 3D endoscopic operation. For all patients, access was made through a 3-4 cm incision in the inframammary fold through the fourth intercostal space. In the NRS-3D group, only a soft-tissue protector, and no additional rib-spreader, was used. Operative visualization was provided by 3D endoscopy in the NRS-3D group. RESULTS: The NRS as well as the RS procedure was successful in all patients without technical repair limitations. Mortality was 0% in both groups. Significant differences were seen for operation times (39.0 min mean shorter operation time in the NRS-3D group; P < 0.001), and length of stay on intensive care unit (1.0 day mean shorter stay in the NRS-3D group; P = 0.002) and in the hospital (1.4 days mean shorter stay in the NRS-3D group; P = 0.003). Postoperative analgesics doses were significantly lower in the NRS-3D group [P = 0.007 (paracetamol); P = 0.123 (metamizole); P = 0.013 (piritramide)]. Postoperative pain rated on a pain-scale from 0 to 10 was significantly lower in the NRS-3D group (mean difference of 1.8; P = 0.006). Patient satisfaction regarding cosmetic results was comparable in both the groups. Repair results, ejection fraction, perioperative morbidity and MACCE during follow-up showed no significant differences between both groups. Early postoperative and follow-up echocardiography showed sufficient repair in all patients of both groups with no case of >mild recurrent mitral regurgitation. CONCLUSIONS: An endoscopic procedure supported by 3D-visualization enables superior depth perception, facilitating an excellent quality of repair results. 3D-visualization is a helpful tool especially for complex reconstruction cases and exact placement of artificial neochordae. With this, an experienced mitral valve surgeon takes shorter operation times. Patients benefit from shorter hospitalization with reduced postoperative pain and early mobilization.