Mycotic pulmonary artery pseudoaneurysm following total arch replacement: a case report.

BACKGROUND: Although the true prevalence and incidence are not clearly known, mycotic pulmonary artery aneurysm is a potentially devastating condition that leads to high mortality, over 60% if untreated. Among them, mycotic pulmonary artery pseudoaneurysm, which occurs in relatively central areas, has rarely been reported. We report an extremely rare case of a late complication with a mycotic pulmonary artery pseudoaneurysm, presumably due to infective endocarditis, in a 68-year-old woman 4 months after total arch replacement. CASE PRESENTATION: A 68-year-old woman was referred to our department for 2 weeks with fever of unknown origin. She had a history of emergency total arch replacement for an acute type A aortic dissection 4 months earlier and chronic rheumatoid arthritis on monthly subcutaneous tocilizumab treatment for several years. Blood culture was positive for Enterococcus faecalis. Transthoracic and transesophageal echocardiography revealed a left ventricular ejection fraction of 58%, severe mitral regurgitation with a 15-mm diameter vegetation on the anterior mitral leaflet, and severe aortic insufficiency with string-like structures. Contrast computed tomography showed a focal saccular outpouching from the right pulmonary artery. On 18F-fluorodeoxyglucose (FDG) positron emission tomography, focal uptake of FDGs was observed along the same lesion of the pulmonary artery and ascending-arch graft. The patient eventually recovered after the surgical intervention of mitral and aortic valve replacement, re-total arch replacement, pulmonary artery repair, application of omental flap, and antibiotics without any evidence of re-infection after 1 year. CONCLUSIONS: We report a successful surgical repair of mycotic pulmonary artery pseudoaneurysm 4 months after total arch replacement for acute type A aortic dissection. This report describes an effective treatment for an extremely rare postoperative condition.

Minimal access aortic surgery.

Recently, there have been significant advances in small incisions through right thoracic cavity including robotic surgery. We have been performing aortic surgery through a partial sternotomy for ascending, arch, and aortic root replacement. In this article, we would like to provide tips for small incision aortic surgery at our institution by showing surgical videos of two cases. Supplementary Information: The online version contains supplementary material available at 10.1007/s12055-023-01578-5.

Overview of acute type A dissection in Japan.

Acute type A aortic dissection is a relatively uncommon but devastating disease and usually requires emergency surgery. Based on the several database projects, a large amount of perioperative patient data has now been accumulated and is expected to be useful in clinical practice. Especially in Japan, the number of surgeries for acute type A aortic dissection has been gradually increasing recently, and the overall mortality rate has stabilized at less than 10%. One of the keys to further improvement in outcomes will be to improve the results of aortic root replacement. In addition, strategies need to be established for very elderly patients, comatose patients, and patients with malperfusion as preoperative conditions. The use of a relatively new device, the frozen elephant trunk, is also increasing and might be changing the surgical outcome. In this report, we describe the current status of acute type A aortic dissection in Japan, with reference to recent guidelines and literature.

Acute type A aortic dissection in adolescents and young adults under 30 years of age: demographics, aetiology and postoperative outcomes of 139 cases.

OBJECTIVES: The prevalence and aetiology of acute aortic dissection type A (AADA) in patients ≤30 years is unknown. The aims of this clinical study were to determine the prevalence and potential aetiology of AADA in surgically treated patients ≤30 years and to evaluate the respective postoperative outcomes in this selective group of patients in a large multicentre study. METHODS: Retrospective data collection was performed at 16 participating international aortic institutions. All patients ≤30 years at the time of dissection onset were included. The postoperative results were analysed with regard to connective tissue disease (CTD). RESULTS: The overall prevalence of AADA ≤30 years was 1.8% (139 out of 7914 patients), including 51 (36.7%) patients who were retrospectively diagnosed with CTD. Cumulative postoperative mortality was 8.6%, 2.2% and 1.4%. Actuarial survival was 80% at 10 years postoperatively. Non-CTD patients (n = 88) had a significantly higher incidence of arterial hypertension (46.6% vs 9.8%; P < 0.001) while AADA affected the aortic root (P < 0.001) and arch (P = 0.029) significantly more often in the CTD group. A positive family history of aortic disease was present in 9.4% of the study cohort (n = 13). CONCLUSIONS: The prevalence of AADA in surgically treated patients ≤30 years is <2% with CTD and arterial hypertension as the 2 most prevalent triggers of AADA. Open surgery may be performed with good early results and excellent mid- to long-term outcomes.

[Emergency Surgical Management for Stanford Type B Acute Aortic Dissection].

Since a certain number of patients with Stanford type B acute aortic dissection have complications such as rupture and malperfusion (complicated type B), it is important to understand the pathogenesis of this condition and to avoid misjudging the timing and methods of invasive treatment such as thoracic endovascular aortic repair( TEVAR) and graft replacement. TEVAR is widely accepted as a less invasive treatment than conventional surgery, and is usually recognized as the first-line treatment, especially for complicated type B. On the other hand, there is still little clear evidence for TEVAR for uncomplicated type B without rupture or malperfusion, and careful selection of cases is considered necessary. In this review article, we describe the acute treatment of Stanford type B acute aortic dissection with reference to recent guidelines and literature.

Updates in aortic wall pathology.

Several studies have investigated the pathogenesis of aortic wall abnormalities such as aortic dissection or aneurysm; however, the comprehensive pathological in situ event involved in the development of the disease is not understood well. The vasa vasorum form a network of capillaries or venules around the adventitia and outer media, which play an important role in the aortic wall structure and function. Impairment of their function may induce tissue hypoxia, impede the transfer of cellular nutrients, and cause aortic medial degeneration, which is considered the major predisposing factor to this aortic wall pathology. This review updates our understanding of the pathological changes in the aortic media and vasa vasorum of patients with aortic dissection and aortic aneurysm.

Therapeutic potential of clinical-grade human induced pluripotent stem cell-derived cardiac tissues.

Objectives: To establish a protocol to prepare and transplant clinical-grade human induced pluripotent stem cell (hiPSC)-derived cardiac tissues (HiCTs) and to evaluate the therapeutic potential in an animal myocardial infarction (MI) model. Methods: We simultaneously differentiated clinical-grade hiPSCs into cardiovascular cell lineages with or without the administration of canonical Wnt inhibitors, generated 5- layer cell sheets with insertion of gelatin hydrogel microspheres (GHMs) (HiCTs), and transplanted them onto an athymic rat MI model. Cardiac function was evaluated by echocardiography and cardiac magnetic resonance imaging and compared with that in animals with sham and transplantation of 5-layer cell sheets without GHMs. Graft survival, ventricular remodeling, and neovascularization were evaluated histopathologically. Results: The administration of Wnt inhibitors significantly promoted cardiomyocyte (CM) (P < .0001) and vascular endothelial cell (EC) (P = .006) induction, which resulted in cellular components of 52.0 ± 6.1% CMs and 9.9 ± 3.0% ECs. Functional analyses revealed the significantly lowest left ventricular end-diastolic volume and highest ejection fraction in the HiCT group. Histopathologic evaluation revealed that the HiCT group had a significantly larger median engrafted area (4 weeks, GHM(-) vs HiCT: 0.4 [range, 0.2-0.7] mm2 vs 2.2 [range, 1.8-3.1] mm2; P = .005; 12 weeks, 0 [range, 0-0.2] mm2 vs 1.9 [range, 0.1-3.2] mm2; P = .026), accompanied by the smallest scar area and highest vascular density at the MI border zone. Conclusions: Transplantation of HiCTs generated from clinical-grade hiPSCs exhibited a prominent therapeutic potential in a rat MI model and may provide a promising therapeutic strategy in cardiac regenerative medicine.

Accuracy of spiked cell counting methods for designing a pre-clinical tumorigenicity study model.

BACKGROUND: Evaluations for the tumorigenicity of transplantation of stem cell products is mandatory for clinical application. It is of importance to establish a system to accurately quantify contaminated tumorigenic cells regardless of the format of stem cell product. In the present report, we aimed to examine the accuracy of the quantification of tumorigenic cell numbers with commonly used 2 methods, quantitative polymerase chain reaction (qPCR) and flow cytometry (FCM) using experimental models of stem cell products spiked with tumorigenic cells. METHODS: Human mesenchymal stem cells (hMSCs) and melanoma Mewo-Luc cells constitutively expressing luciferase were used. We stained Mewo-Luc cells with a cell linker then spiked onto hMSC suspensions and hMSC sheets. We validated the accuracy of 10-fold serial dilution technique for Mewo-Luc cell suspension using a Coulter counter. The samples spiked with Mewo-Luc cells were subjected to qPCR and FCM analyses, respectively for the quantification of Mewo-Luc cells. RESULTS: Ten-fold serial dilutions of Mewo-Luc cells were performed accurately with small deviation. In samples spiked with or less than 100 cells in hMSC suspensions, and samples spiked with or less than 1,000 cells in hMSC sheets showed significantly higher cell numbers in calculations by FCM, respectively (suspensions; qPCR vs FCM: 100 cells: 59 ± 25 vs 232 ± 35 cells, p = 0.022/10 cells: 21 ± 7 vs 114 ± 27 cells, p = 0.030, sheets; qPCR vs FCM: 1,000 cells: 1723 ± 258 vs 5810 ± 878 cells, p = 0.012/100 cells: 110 ± 18 vs 973 ± 232 cells, p = 0.012/10 cells: 20 ± 6 vs 141 ± 36 cells, p = 0.030). CONCLUSION: Differences in accuracy between quantification methods should be considered in designing a tumorigenicity study model.

Novel device prototyping for endoscopic cell sheet transplantation using a three-dimensional printed simulator.

INTRODUCTION: Considering higher risks of candidates for cardiac regenerative therapy with compromised cardiac function, it is anticipated to develop less invasive surgical procedures. In the present study, we aimed to develop a prototype of totally endoscopic cell sheet delivery device and evaluate the surgical technique for epicardial cell sheet placement using three-dimensional (3D) printed simulators based on human computed tomography data. METHODS: We designed an endoscopic cell sheet delivery device with outer and inner frame with self-expandable applicator which can be opened in thoracic cavity. We launched spout line to provide liquids on the applicator surface and tension line to gently bend the applicator dorsally. We prepared human mesenchymal stem cell (MSC) sheets and compared wet/dry conditions of 3D printed heart/porcine heart and applicator to identify suitable conditions for cell sheet transplantation. Finally we validated the feasibility of endoscopic transplantation to anterior and lateral wall of left ventricle using 3D printed simulators. RESULTS: Moist condition of both 3D printed heart/porcine heart surface and applicator at transplantation yielded highest successful rate (100%, p = 0.0197). For both endoscopic transplantation sites, MSC sheets were successfully deployed. The procedure duration was 157 ± 23 s for anterior wall and 123 ± 13 s for the lateral wall in average, respectively. CONCLUSIONS: We developed a novel prototype of endoscopic cell sheet delivery device for minimally-invasive cardiac regenerative therapy utilizing a 3D printed simulator. The commercialization of the prototype may provide a safe minimally-invasive method to deliver potential cardiac regenerative therapy in the future.

[Successful Echo-guided Deployment of Stent Graft for Intraoperative Retrograde Aortic Dissection and Rupture;Report of a Case].

We report a case of chronic dissecting thoracoabdominal aneurysm with intraoperative retrograde aortic dissection and rupture at proximal descending aorta, which was successfully treated by echoguided stent-graft insertion. An 82-year old male underwent thoracoabdominal aortic replacement for dilatation of infra-diaphragmatic aorta. Under F-F bypass, his thoracoabdominal aorta was replaced by a Dacron graft with 4-branches. After he weaned from F-F bypass, we found massive bleeding from proximal descending aorta. Trans-esophageal echocardiography (TEE) showed aortic dissection from the clamp site to the distal anastomotic site of the former total arch replacement. We temporary got hemostasis by suture and surgical glue, and anastomosed a 10 mm-graft to the thoracoabdominal main graft as conduit, then inserted and deployed 2 pieces of stent-graft. Direct echo and TEE contributed to the accurate positioning of them. Bleeding was completely controlled. He well recovered without paraplegia. Post-operative computed tomography (CT) showed good positioning and dilatation of the stentgraft and the perfect reverse remodeling of thoracic aorta.

Histopathological evaluation of aortic dissection: a comparison of congenital versus acquired aortic wall weakness.

OBJECTIVES: The aim of this study was to identify pathological changes of aortic dissection based on histopathological evaluation of aortic wall weakness by comparing patients with and without congenital abnormalities. METHODS: We reviewed records of patients who underwent repair for dissection-related aortic disease between 2008 and 2015. Fifty patients (20 men and 30 women; mean age 66.9 ± 14.0 years) who underwent surgery with subsequent histopathological examination of the aortic wall were divided into 2 groups. Group 1 had congenital abnormalities, including Marfan syndrome and bicuspid aortic valve (n = 5), and Group 2 had no congenital abnormalities (n = 45). We compared the histopathological characteristics of the aortic wall in these patients. RESULTS: There were significant differences in age and body surface area between the 2 groups. Although 80% of Group 1 patients developed dissection at the middle of the media, all Group 2 patients developed dissection at the outer one-third of the media, which is along the pathway of the vasa vasorum of the aortic wall. Both groups showed the same extent of degeneration of the vasa vasorum. Group 1 showed a severe score of mucoid extracellular matrix accumulation in the aortic media. CONCLUSIONS: Although it may be multifactorial, congenital maldevelopment of the media tends to result in dissection of the centre of the media, and acquired aortic wall weakness is concentrated in the outer third of the media. Degeneration of the vasa vasorum may be an important emerging substrate for developing aortic dissection.

Coronary artery and supra-aortic vessel revascularization without aortic clamping for Takayasu arteritis.

Takayasu arteritis (TA) is a rare idiopathic large-vessel vasculitis involving the aorta and its major branches. Coronary artery disease and its surgical management in patients with TA is also a rare clinical entity. We report the case of a 73-year-old woman with TA and 3-vessel coronary artery disease in whom we performed off-pump coronary artery bypass graft concomitant with supra-aortic vessel revascularization.

Intimal Flap Vegetation Following Aortic Root Re-dissection.

A 75-year-old man who had undergone ascending aorta replacement for acute Type A aortic dissection presented with a recurring high fever. Transesophageal echocardiography revealed that a vegetation had formed on the re-dissected intimal flap of the noncoronary sinus of Valsalva. This didactic case suggests that antibiotic prophylactic measures be considered for aortic dissection flaps as for irregular valves susceptible to infective endocarditis.

Surgical resection of two independent primary intimal sarcomas in the left atrium.

Primary intimal sarcoma of the heart is an extremely rare tumor that is known to have a very poor prognosis. We present a case of a 65-year-old man who suffered from deteriorating congestive heart failure due to a severe mitral stenosis caused by a large mobile left atrial tumor. The patient underwent an emergency operation of the tumor in the left atrium. The tumor was attached to the inferior wall of the left atrium. After the resection of the tumor, a second tumor on the interatrial septum, which had not been detected in the preoperative investigation, was discovered and resected. The patient developed acute respiratory failure soon after the operation and succumbed to his illness. The appearance of the main tumor was cauliflower-like, which strongly suggested the possibility of malignancy. Immunohistochemistry revealed that the neoplastic cells were positive for vimentin, desmin, p16, and especially murine double minute 2 (MDM-2). The first tumor was CD34 positive and cdk4 negative, but the second tumor was more anaplastic and CD34 negative and cdk4 positive, which suggests a different origin of the two tumors. The two tumors were diagnosed as intimal sarcomas by MDM-2, which is currently considered a conclusive marker. This is an exceptionally rare case of two simultaneous and possibly independent primary intimal sarcomas in the left atrium.