Accuracy and Sterilizability of In-House Printed Patient-Specific Aortic Model for Surgeon-Modified Stent Grafts-A Workflow Description for Emergency Aortic Endovascular Procedures.

Introduction: The use of 3D-printed aortic models for the creation of surgeon-modified endoprostheses represents a promising avenue in aortic surgery. By focusing on the potential impact of sterilization on model integrity and geometry, this report sheds light on the suitability of these models for creating customized endoprostheses. The study presented here aimed to investigate the safety and viability of 3D-printed aortic models in the context of sterilization processes and subsequent remodeling. Methods: The study involved the fabrication of 3D-printed aortic models using patient-specific imaging data and established additive manufacturing techniques. Five identical aortic models of the same patient were printed. Two models were subjected to sterilization and two to disinfection using commonly employed methods, and one model remained untreated. The models were checked by in-house quality control for deformation (heat map analyses) after the sterilization and disinfection processes. Three models (sterilized, disinfected, and untreated) were sent for ex-house (Lufthansa Technik, AG, Materials Technologies and Central Laboratory Services, Hamburg, Germany) evaluation and subsequent quantification of possible structural changes using advanced imaging and measurement technologies (macroscopic and SEM/EDX examinations). After sterilization and disinfection, each aortic model underwent sterility checks. Results: Based on macroscopic and SEM/EDX examinations, distinct evidence of material alterations attributed to a treatment process, such as a cleaning procedure, was not identified on the three implants. Comparative material analyses conducted via the EDX technique yield consistent results for all three implants. Disinfected and sterilized models tested negative for common pathogens. Conclusions: The evaluation of 3D-printed aortic models' safety after sterilization as well as their suitability for surgeon-modified endoprostheses is a critical step toward their clinical integration. By comprehensively assessing changes in model integrity and geometry after sterilization, this research has contributed to the broader understanding of the use of 3D-printed models for tailor-made endovascular solutions. As medical technologies continue to evolve, research endeavors such as this one can serve as a foundation for harnessing the full potential of 3D printing to advance patient-centered care in aortic surgery.

The Role of Spatial Aortic Arch Architecture in Type B Aortic Dissection.

OBJECTIVE: The incidence of type B aortic dissection (TBAD) is increasing worldwide; however, the underlying pathomechanisms are not conclusively understood. This study explores the geometric architecture of the aortic arch and supra-aortic branches in TBAD patients as opposed to non-TBAD patients. METHODS: Patient characteristics were retrieved from archived medical records. Computer-assisted tomography (CAT) scans of patients with TBAD and carotid stenosis (CS) from two high-volume centers were analyzed. Various aortic arch parameters and take-off angles of the supra-aortic branches of TBAD patients were measured following centerline normalization in comparison CS patients. A compression index (C-index) was calculated from the para-sagittal, and a torsion index (T-index) was calculated from the para-coronal take-off angles of the supra-aortic branches to analyze aortic arch tortuosity. RESULTS: A total of 199 CAT scans were analyzed, namely, 85 in the TBAD group and 114 in the CS group. The average age was 61.5 ± 13.1 years among the TBAD patients and 71 ± 9.3 years among the CS patients. We found a significantly higher proportion of type III aortic arch configurations in TBAD patients compared with CS patients. Further, the aortic arch angle was steeper in the TBAD group. In the para-sagittal plane, the left subclavian artery (LSA) take-off angle was less steep in TBAD patients. In the para-coronal plane, the left carotid artery (LCA) had a less steep take-off angle, while the LSA had a more obtuse take-off angle in the TBAD group when compared with the CS group. In addition, the inter-vessel distance was increased in TBAD patients. Finally, the T-index was increased, suggesting a significant torsion resulting from the deviating take-off angles of the supra-aortic branches supplying the left half of the body as opposed to the innominate artery (IA) in TBAD patients. CONCLUSIONS: Our results suggest several aortic arch-specific geometric configurations in patients suffering from TBAD that significantly differ from those in CS patients. Further functional studies are needed to verify the pathogenetic relevance of our results and their disease-specific causality. Although our data are not mechanistically explorative, they may serve as a basis for identifying future patients with aortic arch morphology at higher risk for TBAD development and who may benefit from more stringent adjustment of risk factors as a primary prevention concept.

Reconstruction for Symptomatic Vertebral Artery Lesion Using Vertebral Artery to Carotid Artery Transposition: A Retrospective Study.

BACKGROUND: A posterior circulation infarction is caused by a vertebral artery (VA) lesion (stenosis or occlusion). The purpose of this study is to assess early and long-term outcomes after open surgery for a VA lesion at the origin. METHODS: In a retrospective study conducted from January 1, 2000 through March 31, 2020 in a single center, patients were treated with vertebral artery to carotid artery transposition (VCT). RESULTS: A total of 28 patients, with a mean age of 65.29 ± 9.81 years (range 45-84), were screened, including 22 patients with VA stenosis and 6 patients with VA occlusion. The complication rate was 21.4% (n = 6), including Horner syndrome (n = 2), lymphocele (n = 1), respiratory failure (n = 1), embolism of a subclavian artery stenosis (n = 1), and vocal cord paralysis (n = 1). The 30-day mortality rate was 0%. Primary patency was 100%. Overall, improvement in symptoms was 85.7% (n = 24) after surgery and 96.4% after 30 days. In the long-term results, primary patency was 100%, and the cumulative patency rate after 60 months was 85.7%, with 1 occlusion of the VA. Cumulative survival rates were 94%, 87%, 69%, and 59% after 12, 24, 60, and 72 months (n = 5). One of the 3 patients died after 60 months because of VA occlusion and posterior circulation infarction. CONCLUSIONS: VCT is a safe, effective, and durable procedure. It provides good stroke protection, symptomatic relief, and perioperative risk at acceptable levels, in experienced hands.

Gimme' the Loop: Modifications to the Squid-Capture Technique for Laser-Fenestrated Thoracic Endografting.

PURPOSE: Laser-fenestrated thoracic endovascular aortic repair (LfTEVAR) in the aortic arch with covering of the left subclavian artery (LSA) orifice is challenging. To optimize fenestration, the so-called squid-capture technique has been introduced. We present here a modification to the technique that may help improve time-efficiency and safety. TECHNIQUE:: During the originally proposed squid-capture maneuver, the stent-graft is deployed in a preset snare wire loop, which is used to pull the stent graft toward the penetration device during in-situ fenestration. In preparation, the guidewire needs to be passed through the loop inside the aortic arch, which can be difficult and may predispose for embolic events. We propose here the creation of a "guidewire-through-snare-loop" configuration outside the body, which can then be reliably transferred into the aortic arch. The modified technique was successfully applied in a patient undergoing LfTEVAR for penetrating aortic ulcers. CONCLUSION: The proposed modification may help facilitate the squid-capture technique for LfTEVAR while saving time and resources. Given that LfTEVAR is becoming more frequently used, it is important to ensure technical success and safety of the procedure.

Neurotherapeutic potential of erythropoietin after ischemic injury of the central nervous system.

Erythropoietin (EPO) is one of the most successful biopharmaceuticals in history and is used for treating anemia of different origins. However, it became clear that EPO could also work in a neuroprotective, antiapoptotic, antioxidative, angiogenetic and neurotropic way. It causes stimulation of cells to delay cell apoptosis, especially in the central nervous system. In rodent models of focal cerebral ischemia, EPO showed an impressive reduction of infarct size by 30% and improvement of neurobehavioral outcome by nearly 40%. A large animal model dealing with ischemia and reperfusion of the spinal cord showed that EPO could reduce the risk of spinal cord injury significantly. In addition, some clinical studies tested whether EPO works in real live clinical settings. One of the most promising studies showed the innocuousness and improvements in follow-up, outcome scales and in infarct size, of EPO-use in humans suffering from ischemic stroke. Another study ended unfortunately in a negative outcome and an increased overall death rate in the EPO group. The most possible reason was the involvement of patients undergoing simultaneously systemic thrombolysis with recombinant tissue plasminogen activator. An experimental study on rats demonstrated that administration of EPO might exacerbate tissue plasminogen activator-induced brain hemorrhage without reducing the ischemic brain damage. This case shows clearly how useful animal models can be to check negative side effects of a treatment before going into clinical trials. Other groups looked in human trials at the effects of EPO on the outcome after ischemic stroke, relation to circulating endothelial progenitor cells, aneurysmal subarachnoid hemorrhage, traumatic brain injury, hemoglobin transfusion thresholds and elective first-time coronary artery bypass surgery. Most of the results were positive, but are based mostly on small group sizes. However, some of the most neglected facts when focusing on experimental setups of ischemia of the central nervous system are issues like age and comorbidities. It might be extremely worthy to consider these points for future projects, because EPO might influence all these factors.