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.

Radiation Exposure and Contrast Agent Use during Endovascular Aortic Repair Using Mobile Versus Fixed Angiography Systems.

BACKGROUND: For (thoracic) endovascular aortic repair ((T)EVAR) procedures, both mobile (standard operating room (SOR)) and fixed C-arm (hybrid operating room (HOR)) systems are available. This study evaluated differences in key procedural parameters, and procedural success for (T)EVAR in the SOR versus the HOR. METHODS: All patients who underwent standard elective (T)EVAR at the Clinic for Vascular and Endovascular Surgery at the University Hospital Duesseldorf, Germany, between 1 January 2012 and 1 January 2019 were included. Data were retrieved from archived medical records. Endpoints were analyzed for SOR versus HOR during (T)EVAR. RESULTS: A total of 93 patients, including 50 EVAR (SOR (n = 20); HOR (n = 30)) and 43 TEVAR (SOR (n = 22); HOR (n= 21)) were included. The dose area product (DAP) for EVAR and TEVAR was lower in the SOR than in the HOR (EVAR, SOR: 1635 ± 1088 cGy·cm2; EVAR, HOR: 7819 ± 8928 cGy·cm2; TEVAR, SOR: 8963 ± 34,458 cGy·cm2; TEVAR, HOR: 14,591 ± 11,584 cGy·cm2 (p < 0.05)). Procedural fluoroscopy time was shorter in the SOR than in the HOR for EVAR and TEVAR (EVAR, SOR: 7 ± 4 min; EVAR, HOR: 18.8 ± 11.3 min; TEVAR, SOR: 6.6 ± 9.6 min; TEVAR, HOR: 13.9 ± 11.8 min (p < 0.05)). Higher volumes of contrast agent were applied during EVAR and TEVAR in the SOR than in the HOR (EVAR, SOR: 57.5 ± 20 mL; EVAR: HOR: 33.3 ± 5 mL (p < 0.05); TEVAR; SOR: 71.5 ± 53.4 mL, TEVAR, HOR: 48.2 ± 27.5 mL (p ≥ 0.05). CONCLUSION: The use of a fixed C-arm angiography system in the HOR results in higher radiation exposure and longer fluoroscopy times but lower contrast agent volumes when compared with mobile C-arm systems in the SOR. Because stochastic radiation sequelae are more likely to be tolerated in an older patient population and, in addition, there is a higher incidence of CKD in this patient population, allocation of patients to the HOR for standard (T)EVAR seems particularly advisable based on our results.

Relative Thrombus Burden Ratio Reveals Overproportioned Intraluminal Thrombus Growth-Potential Implications for Abdominal Aortic Aneurysm.

Background: An intraluminal, non-occlusive thrombus (ILT) is a common feature in an abdominal aortic aneurysm (AAA). This study investigated the relative progression of ILT vs. AAA volume using a novel parameter, the so-called thrombus burden ratio (TBR), in non-treated AAAs. Parameters potentially associated with TBR progression were analyzed and TBR progression in large vs. small and fast- vs. slow-growing AAAs was assessed. Methods: This retrospective, single-center study analyzed sequential contrast-enhanced computed tomography angiography (CTA) scans between 2009 and 2018 from patients with an AAA before surgical treatment. Patients' medical data and CTA scans were analyzed at two given time points. The TBR was calculated as a ratio of ILT and AAA volume, and relative TBR progression was calculated by normalization for time between sequential CTA scans. Spearman's correlation was applied to identify morphologic parameters correlating with TBR progression, and multivariate linear regression analysis was used to evaluate the association of clinical and morphological parameters with TBR progression. Results: A total of 35 patients were included. The mean time between CT scans was 16 ± 15.9 months. AAA volume progression was 12 ± 3% and ILT volume progression was 36 ± 13%, resulting in a TBR progression of 11 ± 4%, suggesting overproportioned ILT growth. TBR progression was 0.8 ± 0.8% per month. Spearman's correlation verified ILT growth as the most relevant parameter contributing to TBR progression (R = 0.51). Relative TBR progression did not differ significantly in large vs. small and fast- vs. slow-growing AAAs. In the multivariate regression analysis, none of the studied factors were associated with TBR progression. Conclusion: TBR increases during AAA development, indicating an overproportioned ILT vs. AAA volume growth. The TBR may serve as a useful parameter, as it incorporates the ILT volume growth relative to the AAA volume, therefore combining two important parameters that are usually reported separately. Yet, the clinical relevance in helping to identify potential corresponding risk factors and the evaluation of patients at risk needs to be further validated in a larger study cohort.

The Comparison of Endovascular and Open Surgical Treatment for Ruptured Abdominal Aortic Aneurysm in Terms of Safety and Efficacy on the Basis of a Single-Center 30-Year Experience.

OBJECTIVE: Ruptured abdominal aortic aneurysm (rAAA) is a critical condition with a high mortality rate. Over the years, endovascular aortic repair (EVAR) has evolved as a viable treatment option in addition to open repair (OR). The primary objective of this study was to compare the safety and efficacy of EVAR and OR for the treatment of rAAA based on a comprehensive analysis of our single-centre 30-year experience. METHODS: Patients treated for rAAA at the Department of Vascular and Endovascular Surgery, University Hospital Düsseldorf, Germany from 1 January 1993 to 31 December 2022 were included. Relevant information was retrieved from archived medical records. Patient survival and surgery-related complications were analysed. RESULTS: None of the patient-specific markers, emergency department-associated parameters, and co-morbidities were associated with patient survival. The 30-day and in-hospital mortality was higher in the OR group vs. in the EVAR group (50% vs. 8.7% and 57.1% vs. 13%, respectively). OR was associated with more frequent occurrence of more severe complications when compared to EVAR. Overall patient survival was 56 ± 5% at 12 months post-surgery (52 ± 6% for OR vs. 73 ± 11% for EVAR, respectively) (p < 0.05). Patients ≥70 years of age showed poorer survival in the OR group, with a 12-month survival of 42 ± 7% vs. 70 ± 10% for patients <70 years of age (p < 0.05). In the EVAR group, this age-related survival advantage was not found (12-month survival: ≥70 years: 67 ± 14%, <70 years: 86 ± 13%). Gender-specific survival was similar regardless of the applied method of care. CONCLUSION: OR was associated with more severe complications in our study. EVAR initially outperformed OR for rAAA regarding patient survival while re-interventions following EVAR negatively affect survival in the long-term. Elderly patients should be treated with EVAR. Gender does not seem to have a significant impact on survival.

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.

Ethanol Enhances Endothelial Rigidity by Targeting VE-Cadherin-Implications for Acute Aortic Dissection.

(1) Background: Acute aortic dissection (AAD) is caused by an endothelial entry tear followed by intimomedial delamination of the outer layers of the vessel wall. The established risk factors include hypertension and smoking. Another rising candidate risk factor is excessive alcohol consumption. This experimental study explores the effects of nicotine (Nic), angiotensin II (Ang II), and ethanol (EtOH) on human aortic endothelial cells (hAoEC). (2) Methods: HAoECs were exposed to Nic, Ang II, and EtOH at different dose levels. Cell migration was studied using the scratch assay and live-cell imaging. The metabolic viability and permeability capacity was investigated using the water-soluble tetrazolium (WST)-1 assay and an in vitro vascular permeability assay. Cell adherence was studied by utilizing the hanging drop assay. The transcriptional and protein level changes were analyzed by RT-qPCR, Western blotting and immunohistochemistry for major junctional complexing proteins. (3) Results: We observed reduced metabolic viability following Ang II and EtOH exposure vs. control. Further, cell adherence was enhanced by EtOH exposure prior to trituration and by all risk factors after trituration, which correlated with the increased gene and protein expression of VE-cadherin upon EtOH exposure. The cell migration capacity was reduced upon EtOH exposure vs. controls. (4) Conclusion: Marked functional changes were observed upon exposure to established and potential risk factors for AAD development in hAoECs. Our findings advocate for an enhanced mechanical rigidity in hAoECs in response to the three substances studied, which in turn might increase endothelial rigidity, suggesting a novel mechanism for developing an endothelial entry tear due to reduced deformability in response to increased shear and pulsatile stress.

Effect of Gelatin-Based Hemostats on Fibroblasts and Relevant Growth Factors in Wound Healing.

Gelatin-based hemostats have been used in various surgical fields and showed advantageous effects on central aspects of wound healing when compared to cellulose-based hemostats. Nevertheless, the influence of gelatin-based hemostats on wound healing has not been fully explored yet. Hemostats were applied to fibroblast cell cultures for 5, 30, 60 min, 24 h, 7 and 14 days and measurements were taken at 3, 6, 12, 24 h and 7 or 14 days, respectively. Cell proliferation was quantified after different exposure times and a contraction assay was conducted to measure the extent of the extracellular matrix over time. We further assessed quantitative levels of vascular endothelial growth factor and basic fibroblast growth factor using enzyme-linked immunosorbent assay. Fibroblast counts decreased significantly at 7 and 14 days independent of the application duration (p < 0.001 for 5 min application). The gelatin-based hemostat did not have a negative impact on cell matrix contraction. After application of gelatin-based hemostat, the basic fibroblast growth factor did not change; yet, the vascular endothelial growth factor significantly increased after a prolonged 24 h application time when compared to controls or to a 6 h exposure (p < 0.05). Gelatin-based hemostats did not impair contraction of the extracellular matrix or growth factor production (vascular endothelial growth factor and basic fibroblast growth factor), while cell proliferation diminished at late time points. In conclusion, the gelatin-based material seems to be compatible with central aspects of wound healing. For further clinical assessment, future animal and human studies are necessary.

E-cigarette exposure augments murine abdominal aortic aneurysm development: role of Chil1.

AIMS: Abdominal aortic aneurysm (AAA) is a common cardiovascular disease with a strong correlation to smoking, although underlying mechanisms have been minimally explored. Electronic cigarettes (e-cigs) have gained recent broad popularity and can deliver nicotine at comparable levels to tobacco cigarettes, but effects on AAA development are unknown. METHODS AND RESULTS: We evaluated the impact of daily e-cig vaping with nicotine on AAA using two complementary murine models and found that exposure enhanced aneurysm development in both models and genders. E-cigs induced changes in key mediators of AAA development including cytokine chitinase-3-like protein 1 (CHI3L1/Chil1) and its targeting microRNA-24 (miR-24). We show that nicotine triggers inflammatory signalling and reactive oxygen species while modulating miR-24 and CHI3L1/Chil1 in vitro and that Chil1 is crucial to e-cig-augmented aneurysm formation using a knockout model. CONCLUSIONS: In conclusion our work shows increased aneurysm formation along with augmented vascular inflammation in response to e-cig exposure with nicotine. Further, we identify Chil1 as a key mediator in this context. Our data raise concerns regarding the potentially harmful long-term effects of e-cig nicotine vaping.

Nicotine Potentially Alters Endothelial Inflammation and Cell Adhesion via LGALS9.

BACKGROUND: The endothelial cell layer is essential for the maintenance of various blood vessel functions. Major risk factors for endothelial dysfunction that contribute to aortic pathologies such as abdominal aortic aneurysm (AAA) and aortic dissection (AD) include smoking tobacco cigarettes and hypertension. This study explores the effects of nicotine (Nic) and angiotensin II (Ang II) on human aortic endothelial cells (HAoECs) at a transcriptional level. METHODS: HAoECs were exposed to 100 nM Nic and/or 100 nM Ang II. RNA sequencing (RNA-Seq) was performed to identify regulated genes following exposure. Results were validated applying RT-qPCR. GeneMANIA was used to perform in silico analysis aiming to identify potential downstream interacting genes in inflammatory, cell-adhesion, endothelial cell proliferation, and coagulation pathways. RESULTS: RNA-Seq identified LGALS9 (Galectin-9) as being potentially regulated following Nic exposure, while subsequent RT-qPCR experiments confirmed the transcriptional regulation (p < 0.05). Subsequent in silico analysis identified potential candidate genes for interacting with LGALS9 in different gene sets. Of the top 100 genes potentially interacting with LGALS9, 18 were inflammatory response genes, 28 were involved in cell adhesion, 2 in cell proliferation, and 6 in coagulation. CONCLUSION: Nic exposure of HAoECs causes a significant increase in LGALS9 at a transcriptional level. LGALS9 itself may serve as key regulator for essential endothelial cell processes via interfering with various signaling pathways and may thus represent a potentially novel target in the pathogenesis of aortic pathologies.

Early Results of a Novel Hybrid Prosthesis for Treatment of Acute Aortic Dissection Type A With Distal Anastomosis Line Beyond Aortic Arch Zone Zero.

Introduction: Acute aortic dissection type A (AADA) is associated with high perioperative morbidity and mortality. A novel non-covered hybrid prosthesis (Ascyrus Medical Dissection Stent (AMDS) Hybrid Prosthesis, Cryolife/Jotec, Hechingen, Germany) can be easily implanted to stabilize the true lumen (TL), improve remodeling, and preserve organ perfusion. Although developed for implantation in aortic zone 0, occasionally, partial replacement of the aortic arch and further distal implantation of AMDS may appear favorable. Implantation of AMDS with anastomosis line beyond zone 0 has not been described yet. Materials and Methods: Between 08/2019 and 12/2020, a total of n = 97 patients were treated due to AADA at a single University hospital. Of those, n = 28 received an AMDS hybrid prosthesis, of whom in eight patients, due to intraoperative finding the distal anastomosis line was placed distal to the brachiocephalic trunk. Three patients had AMDS implantation in zone I and four were treated by implantation of the prostheses in zone II, and one patient had the implantation performed in zone III. Clinical outcome and the development of a proportional area of TL and false lumen (FL) at defined levels of the thoracic aorta were analyzed. Results: None of the surviving patients (87.5%) showed signs of clinical malperfusion (i.e., stroke, spinal cord injury, and need for dialysis). A postoperative CT scan showed an open TL in all patients. The proportion of TL with respect to total aortic diameter (TL+FL) was postoperatively significantly higher in zone III (p = 0.016) and at the level of T11 (p = 0.009). The mean area of TL+FL was comparable between pre- and postoperative CT-scan (p = n.s.). One patient with preoperative resuscitation died of multiple organ failure on extracorporeal life support on postoperative day 3. Conclusion: Implantation of AMDS can be safely performed in patients who need partial replacement of the aortic arch beyond zone 0. The advantages of the AMDS can be combined with those of the total arch repair (remodeling of the arch and prevention of TL collapse) without the possible disadvantages (risk of spinal cord injury).

First-in-Human Clinical Application of the Medyria TrackCath System in Endovascular Repair of Complex Aortic Aneurysms (ACCESS Trial): A Prospective Multicenter Single-Arm Clinical Trial.

PURPOSE: The Medyria TrackCath Catheter (MedTCC) is an innovative, thermal convection-based blood flow velocity (BFV) tracking catheter that may be used during complex aortic endovascular procedures for identification and catheterization of target orifices. The ACCESS Trial analyzes the safety and performance of the MedTCC for targeted vessel catheterization to generally evaluate the feasibility of thermal convection-based BFV. MATERIALS AND METHODS: We performed a first-in-human, proof-of-concept, prospective single-arm multicenter clinical trial between March 2018 and February 2019 in patients who underwent endovascular aortic procedures at 4 high-volume centers. During these procedures, the MedTCC was advanced over a guidewire through the femoral access. The D-shape was enfolded in the reno-visceral part of the aorta and target orifices were identified and catheterized with a guidewire via the side port of the MedTCC through BFV tracking. BFV measurements were performed at baseline (Baseline-BFV), alignment to the orifice (Orifice-BFV), and following catheterization (Confirmation-BFV) to prove correct identification and catheterization of target orifices. The procedural success rate, the catheterization success rate, procedure-related parameters, and (serious) adverse events ((S)AE) during the follow-up were analyzed. RESULTS: A total of 38 patients were included in the safety group (SG) and 26 in the performance group (PG). The procedural success rate was 89% (PG), the MedTCC catheterization success rate was 98% (PG). The MedTCC reliably measured BFV changes indicated by significant differences in BFV between Baseline-BFV and Orifice-BFV (p<0.05). Median (interquartile range; IQR) fluoroscopy time per orifice was 5.0 (1.5-8.5) minutes [total surgery 49 (26-74) minutes], median (IQR) contrast agent used per orifice was 1.0 (0-5.0) mL [total surgery 80 (40-100) mL], and median (IQR) MedTCC-based procedural time was 3.0 (2.0-6.0) minutes. There was no device-related SAE. CONCLUSIONS: The ACCESS Trial suggests that BFV measurement allows for reliable target orifice identification and catheterization. The use of MedTCC is safe and generates short fluoroscopy time and low contrast agent use, which in turn might facilitate complex endovascular procedures.

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.

Hyperlipidemia does not affect development of elastase-induced abdominal aortic aneurysm in mice.

BACKGROUND AND AIMS: Hyperlipidemia is a suggested risk factor for abdominal aortic aneurysm (AAA). However, whether hyperlipidemia is causally involved in AAA progression remains elusive. Here, we tested the hypothesis that hyperlipidemia aggravates AAA formation in the widely used porcine pancreatic elastase (PPE) model of AAA in mice with varying levels of plasma lipids. METHODS: Prior to PPE-surgery, 8-week-old male C57BL/6J mice (n = 32) received 1·1011 viral genomes of rAAV8-D377Y-mPcsk9 or control rAAV8 via the tail vein. Mice were fed either western type diet or regular chow. At baseline and during the 28 days following PPE-surgery, mice underwent weekly ultrasonic assessment of AAA progression. Experiments were repeated using Apolipoprotein E knockout (ApoE-/-) mice (n = 7) and wildtype C57BL/6J mice (n = 5). RESULTS: At sacrifice, maximal intergroup plasma cholesterol and non-HDL/HDL ratio differences were >5-fold and >20-fold, respectively. AAA diameters expanded to 150% of baseline, but no intergroup differences were detected. This was verified in an independent experiment comparing 8-week-old male ApoE-/- mice with wildtype mice. Histological evaluation of experimental AAA lesions revealed accumulated lipid in neointimal and medial layers, and analysis of human AAA lesions (n = 5) obtained from open repair showed medial lipid deposition. CONCLUSIONS: In summary, we find that lipid deposition in the aortic wall is a feature of PPE-induced AAA in mice as well as human AAA lesions. Despite, our data do not support the hypothesis that hyperlipidemia contributes to AAA progression.

Arteriogenesis of the Spinal Cord-The Network Challenge.

Spinal cord ischemia (SCI) is a clinical complication following aortic repair that significantly impairs the quality and expectancy of life. Despite some strategies, like cerebrospinal fluid drainage, the occurrence of neurological symptoms, such as paraplegia and paraparesis, remains unpredictable. Beside the major blood supply through conduit arteries, a huge collateral network protects the central nervous system from ischemia-the paraspinous and the intraspinal compartment. The intraspinal arcades maintain perfusion pressure following a sudden inflow interruption, whereas the paraspinal system first needs to undergo arteriogenesis to ensure sufficient blood supply after an acute ischemic insult. The so-called steal phenomenon can even worsen the postoperative situation by causing the hypoperfusion of the spine when, shortly after thoracoabdominal aortic aneurysm (TAAA) surgery, muscles connected with the network divert blood and cause additional stress. Vessels are a conglomeration of different cell types involved in adapting to stress, like endothelial cells, smooth muscle cells, and pericytes. This adaption to stress is subdivided in three phases-initiation, growth, and the maturation phase. In fields of endovascular aortic aneurysm repair, pre-operative selective segmental artery occlusion may enable the development of a sufficient collateral network by stimulating collateral vessel growth, which, again, may prevent spinal cord ischemia. Among others, the major signaling pathways include the phosphoinositide 3 kinase (PI3K) pathway/the antiapoptotic kinase (AKT) pathway/the endothelial nitric oxide synthase (eNOS) pathway, the Erk1, the delta-like ligand (DII), the jagged (Jag)/NOTCH pathway, and the midkine regulatory cytokine signaling pathways.

Endovascular Occlusion of a Renal Arteriovenous Fistula with Renal Vein Aneurysm Formation for Rupture Prevention.

PURPOSE: To report the effectiveness of left renal artery (LRA) occlusion using Amplatzer Vascular Plug (AVP) II as treatment for a high-flow renal arteriovenous fistula (RAVF) with multiple renal vein aneurysms (RVA) to prevent aneurysm rupture and cardiac decompensation. CASE REPORT: A 59-year-old female suffering from a post-traumatic RAVF presented with tachycardia and increased cardiac output (CO). Doppler ultrasonography and computed tomography (CT) scan revealed a high-flow RAVF with multiple RVAs and unilateral critically reduced kidney function. Appreciating recent interventional therapeutic advances, the patient was treated with endovascular placement of AVP II into the left renal artery (LRA) resulting in complete occlusion of the RAVF to effectively reduce the risk of RVA rupture and cardiac decompensation. No anti-platelet medication was administrated after the occlusion of the LRA. The patient's physical capacity improved since right heart volume strain was normalized, and CO was reduced. CONCLUSION: Transbrachial AVP II occlusion of the LRA is effective to occlude high-flow RAVFs to prevent risk of life-threatening RVA rupture. Additional follow-up is warranted to verify long-term effectiveness of this approach.

Acute Limb Ischemia-Much More Than Just a Lack of Oxygen.

Acute ischemia of an extremity occurs in several stages, a lack of oxygen being the primary contributor of the event. Although underlying patho-mechanisms are similar, it is important to determine whether it is an acute or chronic event. Healthy tissue does not contain enlarged collaterals, which are formed in chronically malperfused tissue and can maintain a minimum supply despite occlusion. The underlying processes for enhanced collateral blood flow are sprouting vessels from pre-existing vessels (via angiogenesis) and a lumen extension of arterioles (via arteriogenesis). While disturbed flow patterns with associated local low shear stress upregulate angiogenesis promoting genes, elevated shear stress may trigger arteriogenesis due to increased blood volume. In case of an acute ischemia, especially during the reperfusion phase, fluid transfer occurs into the tissue while the vascular bed is simultaneously reduced and no longer reacts to vaso-relaxing factors such as nitric oxide. This process results in an exacerbative cycle, in which increased peripheral resistance leads to an additional lack of oxygen. This whole process is accompanied by an inundation of inflammatory cells, which amplify the inflammatory response by cytokine release. However, an extremity is an individual-specific composition of different tissues, so these processes may vary dramatically between patients. The image is more uniform when broken down to the single cell stage. Because each cell is dependent on energy produced from aerobic respiration, an event of acute hypoxia can be a life-threatening situation. Aerobic processes responsible for yielding adenosine triphosphate (ATP), such as the electron transport chain and oxidative phosphorylation in the mitochondria, suffer first, thus disrupting the integrity of cellular respiration. One consequence of this is irreparable damage of the cell membrane due to an imbalance of electrolytes. The eventual increase in net fluid influx associated with a decrease in intracellular pH is considered an end-stage event. Due to the lack of ATP, individual cell organelles can no longer sustain their activity, thus initiating the cascade pathways of apoptosis via the release of cytokines such as the BCL2 associated X protein (BAX). As ischemia may lead to direct necrosis, inflammatory processes are further aggravated. In the case of reperfusion, the flow of nascent oxygen will cause additional damage to the cell, further initiating apoptosis in additional surrounding cells. In particular, free oxygen radicals are formed, causing severe damage to cell membranes and desoxyribonucleic acid (DNA). However, the increased tissue stress caused by this process may be transient, as radical scavengers may attenuate the damage. Taking the above into final consideration, it is clearly elucidated that acute ischemia and subsequent reperfusion is a process that leads to acute tissue damage combined with end-organ loss of function, a condition that is difficult to counteract.

Outcomes after Open Surgery for Inflammatory Abdominal Aortic Aneurysm: A 10-Year Single-Center Experience.

BACKGROUND: Inflammatory abdominal aortic aneurysms (IAAAs) are rare clinical entities with an exaggerated inflammatory component. The aim of this study is to report outcomes of a single-center 10-year experience in open surgical management of IAAA and to compare the results with noninflammatory, atherosclerotic abdominal aortic aneurysms (non-IAAAs). METHODS: We retrospectively reviewed the medical records of 18 patients with IAAA selected out of patients with AAA who underwent open surgery in the Department of Vascular and Endovascular Surgery at the University Hospital Dusseldorf from January 2006 to December 2015. These patients were matched with controls, selected from a prospectively retained database of patients with AAA undergoing open surgery during the study period. A 1:2 case-control match regarding age, gender, and year of treatment was performed. We analyzed both groups for preoperative parameters, intraoperative findings, and early postoperative outcomes. RESULTS: The 2 groups showed considerable similarities with no significant differences in the clinical features. Both groups outlined comparable aneurysm size (62 vs. 56 mm); however, the mean preoperative C-reactive protein was found to be significantly elevated in the study group (mean value: 2.6 vs. 0.9 mg/dL, P < 0.05). Most patients were operated using a standard transperitoneal median laparotomy approach; only 1 patient of each group was operated using a left retroperitoneal approach. There was no significant difference in operation time (190 vs. 194 min) and 30-day mortality 0%. The in-hospital mortality was 11% in the study group and 0% in the control group. We found a significant higher complication rate in the study group 10 (56%) vs. 12 (33%). The major complications were also more frequent in the study group 4 (22%) vs. 6 (16.7%). IAAA showed a statistically significant longer length of intensive care unit and hospital stay when compared with non-IAAA (7 and 20 days vs. 2 and 14 days, P < 0.05). IAAAs outlined a significantly greater transfusion requirement for erythrocytes and fresh frozen plasma than non-IAAA. CONCLUSIONS: Open surgical treatment of IAAA guarantees a regression of the inflammatory process in most patients, which was detected through ultrasound in follow-up examination, although the approach to the surgical site is highly demanding. IAAA exhibits clear gender predominance and is associated with significantly higher transfusion requirement, early morbidity, and length of stay.

Retrograde Aortomesenteric Bypass with Left Retrorenal Route-"French Bypass" in 16 Cases of Chronic Mesenteric Ischemia.

BACKGROUND: There are several options for treating patients suffering from chronic mesenteric ischemia (CMI). One possibility contains bypass grafting following a left renal route to avoid inter alia kinking of the bypass. This study reviews the results of 16 patients suffering from CMI treated with this bypass technique, called "French Bypass" (FB). METHODS: A retrospective study conducted between June 1, 2002, and December 31, 2015. Sixteen patients were included with an average age of 54.6 years (10 women) who were treated with FB. Risk factors, surgical course, and follow-up were evaluated. RESULTS: Average stay in hospital took 28.4 days, with mostly minor complications occurring. Overall, 4 cases of FB occlusion were diagnosed in between 30 days after surgery, of which 3 made interventions necessary. Primary patency rates were 75%/56%/56% after 12/24/60 months. Overall survival rate after 60 month was 78%. CONCLUSIONS: The FB is a sufficient option for treatment of CMI combining advantages of anterograde and retrograde bypass grafting, with comparable outcome to established techniques in visceral vessel reconstruction.

Surgical management of iliofemoral vein thrombosis during pregnancy and the puerperium.

BACKGROUND: The risk of deep venous thrombosis is elevated during pregnancy and the puerperium. Therapy is usually limited to conservative measures as invasive thrombus removal is feared because of possible complications. However, leg- or life-threatening situations require fast thrombus removal, and the long-term rate of post-thrombotic syndrome (PTS) may be reduced by venous recanalization. Our center's experience may give support to surgical venous thrombectomy (VT). METHODS: Between 1996 and 2016, all women who received VT for pregnancy-related deep venous thrombosis in our department were included. Retrospective data were combined with a current follow-up. RESULTS: The study included 82 women with a mean age of 29 years (17-38 years). An additional arteriovenous fistula was performed in 79 and planned simultaneous cesarean section in 13 patients. Neither pulmonary emboli nor fetal complications occurred during surgery, and perioperative and postoperative mortality was 0%. Operative revision was required in 38% mainly for rethrombosis (24%) and bleeding (12%). One fetus died 2 months after VT of unrelated causes. After a mean of 83 months, complete venous recanalization was seen in 88%, venous valve sufficiency in 90%, and PTS in 31% without any ulcers. At 10 years, PTS incidence rose to reach 50% with limited statistical significance because of the number of patients reaching long-term follow-up. CONCLUSIONS: Iliofemoral venous recanalization during pregnancy can be performed safely in a specialized center, with lower PTS rates than in historical controls.

Crossover Thrombectomy of Hypogastric Arteries.

To describe a case of intraoperative thrombotic occlusion of the left hypogastric artery (HA) during endovascular treatment for acute Leriche syndrome and a feasible technique for HA embolectomy and prevention of pelvic ischemia. After bilateral transfemoral vascular access Fogarty thrombectomy of the infrarenal aorta and bilateral common and external iliac arteries was performed. Then, an intraoperative angiography revealed new thrombotic occlusion of the left HA. Ipsilateral transfemoral approach was impeded by a strong angulation between HA and iliac artery. Therefore, a right-transfemoral approach was used for crossover Fogarty thrombectomy. The thrombus was mobilized into the left common iliac artery and could easily be removed by left-transfemoral embolectomy. No complications occurred. Crossover thrombectomy is a feasible technique for endovascular treatment of acute thrombotic occlusion of HAs. Occlusion of HA should be treated whenever possible.