Changes in the Remaining Iliac Artery According to Retrograde Flow after Aorto-Femoral Bypass in Abdominal Aortic Aneurysms.

BACKGROUND: Considering a patient's anatomy and vascular conditions, aorto-femoral bypass is a treatment approach for the open repair of abdominal aortic aneurysms. This study aimed at evaluating changes in the remnant iliac artery and their correlation with the preservation state of retrograde flow from femoral anastomosis. METHODS: Of 221 patients who underwent abdominal aortic aneurysm surgery between 2007 and 2022 in Pusan National University Hospital, 29 patients who underwent aorto-femoral bypass were included in this retrospective cohort study. Of these patients, 21 underwent aortobifemoral bypass and 8 underwent aortoiliac-and-femoral bypass. The change in size of the iliac artery from preoperative to postoperative and whether this difference in size depended on the status of postoperative retrograde flow were investigated. Additionally, factors affecting overall mortality and ischemic complications were identified. RESULTS: The median duration from operation to the last follow-up was 2069.5 days (about 5.7 years). The average age of the patients was 78.1 years, and the proportion of males was 75.9%. In cases of disappearance of postoperative retrograde flow from the femoral anastomosis, the postoperative iliac artery size was significantly reduced compared to its preoperative size (18.4 ± 18.9 mm vs. 13.2 ± 7.9 mm, respectively; P = 0.04). The group with maintained retrograde flow had significantly larger residual common iliac artery size than the group with disappearance of flow. (20.0 ± 28.0 mm vs. 14.6 ± 8.5 mm, respectively; P = 0.02). Disappearance of retrograde flow was a significant factor in the iliac artery size reduction after surgery (odds ratio, 2.5; 95% confidence interval, 1.9-5.3; P = 0.02). Three patients with maintained retrograde flow (18.8%) required intervention owing to an increase in the size of the iliac artery. The factors that significantly influenced overall death as analyzed by Cox proportional hazard regression were chronic obstructive pulmonary disease (hazard ratio, 36.8; 95% confidence interval, 1.6-870.0; P = 0.03), peripheral arterial occlusive disease (hazard ratio, 12.7; 95% confidence interval, 1.4-115.8; P = 0.02), and disappearance of retrograde flow (hazard ratio, 8.7; 95% confidence interval, 1.2-63.9; P = 0.03). CONCLUSIONS: Among the open repair methods for abdominal aortic aneurysms, if retrograde flow was not maintained through femoral anastomosis when aorto-femoral bypass was performed, the size of the remaining iliac artery decreased. However, loss of retrograde flow increased long-term mortality. When aorto-femoral bypass is performed, regular imaging follow-up is necessary at appropriate intervals to check the remnant iliac artery and retrograde flow.

Staged angioplasty using a full-length balloon catheter to achieve maturation of arteriovenous fistulas.

PURPOSE: To evaluate the efficacy of staged full-length balloon-assisted maturation (BAM) for the maturation of arteriovenous fistulas (AVFs) on entire segmental veins, including stenosis, causing primary AVF failure. METHODS: This study included patients who underwent AVF surgery using an autogenous vein between February 2020 and June 2021 and received staged angioplasty with a full-length balloon catheter. To minimize balloon overlap and the risk of barotrauma to the immature vein, serial-staged upsizing balloon angioplasty with a long balloon catheter covering the entire vein segment was employed approximately 2 weeks apart. RESULTS: Twenty-three patients (mean age, 69.50 years; mean follow-up, 620.62 days) with average diameters of the radial artery and cephalic vein at 2.14 ± 0.5 mm and 2.43 ± 0.5 mm, respectively, were enrolled. In the first procedure, the average AVF diameter and flow were 4.03 ± 0.57 mm and 438.08 ± 220.95 mL/min, respectively, with juxta-anastomotic stenosis (JAS) present in 61.5% of cases. After staged full-length BAM, the average fistula diameter and flow improved to 5.95 ± 0.86 mm and 717.52 ± 305.95 mL/min, respectively. Maturation was achieved in 87% of the cases. No hematomas or ruptures occurred around the arterialized veins. Despite successful maturation and cannulation, 65.2% of the patients required additional percutaneous transluminal angioplasty (PTA) during the follow-up period. The necessity for PTA was determined by the presence of JAS prior to the first staged full-length BAM, with an odds ratio of 11.74 (95% confidence interval: 1.31-104.96, P = 0.03). CONCLUSION: Staged full-length BAM can be safely used in patients with small veins requiring further maturation. Most patients achieved successful cannulation following maturation without post-procedural complications. CLINICAL SIGNIFICANCE: Staged full-length BAM is a safe and effective method for enhancing maturation in patients with underdeveloped small veins.

Rejoining Veins for Forced Maturation of Small-Caliber Arteriovenous Fistula.

BACKGROUND: To evaluate the efficacy of rejoining mainstream and accessory veins for forced maturation of autogenous arteriovenous fistula (AVF). METHODS: Twenty-three patients who underwent forced maturation through vein rejoining between January 2018 and September 2022 were included. In cases where AVF maturation failure due to the presence of accessory veins, rejoining was primarily considered when distinguishing the main branch becomes challenging. This difficulty typically occurs when the sizes of the 2 vessels are nearly equal and the combined diameters of these veins exceed 6 mm. RESULTS: The mean age and follow-up duration were 57.39 ± 16.22 years and 965.65 ± 573.42 days, respectively. Rejoining of both arterial and venous cannulation sites was performed in 11 patients (47.8%), and rejoining of only the venous cannulation site or only the arterial cannulation site was performed in 11 patients (47.8%) and 1 patient (4.3%), respectively. The mean vein size was 0.35 ± 0.06 cm before rejoining and 0.69 ± 0.07 cm after surgery, indicating a significant increase in size (P < 0.01), whereas the flow did not change significantly following rejoining surgery. Maturation and cannulation success was 100%. The 1-year primary patency rate after surgery was 82.0%. During the follow-up period, 34.8% of the patients required additional percutaneous transluminal angioplasty to maintain patency, and 2 patients (11.8%) had stenosis in the rejoined section. CONCLUSIONS: Rejoining surgery is an effective method for achieving AVF maturation in patients with accessory veins when identification of the mainstream vein is difficult, and this method may be considered when achieving maturation by sacrificing 1 vein is expected to be challenging.

Effects of Platycodon grandiflorum on Gut Microbiome and Immune System of Immunosuppressed Mouse.

Platycodon grandiflorum (PG) is a perennial plant that has been used as a traditional remedy to control immune-related diseases. PG was steamed and dried to improve its taste (PGS). The aim of the study was to investigate the effects of PG and PGS (PG-diets) on the gut microbiome and immune system. We treated PG-diets to immunosuppressed mice via cyclophosphamide (CPA) injection. After two weeks of the supplement, we evaluated specific genera related to body weight and serum immunoglobulin levels and analyzed 16S rRNA sequencing and metagenomics statistical analysis. PG-diets groups showed an increased abundance of microorganisms in immunodeficient mice compared to the control group (NC). Moreover, Akkermansia significantly decreased in response to the CPA in the NC group at the genus level, whereas its abundance increased in the PG-diets groups. We also found that the modulation of the gut microbiome by PG-diets was correlated with body weight, IgA, and IgM levels. The results demonstrate that PG-diets may improve the health benefits of immunosuppressed mice by altering the gut microbiome, though not much difference was found between PG and PGS treatments. Finally, this is the first study showing the effects of PGS-diets on the gut microbiome and immune system as a potential nourishing immunity supplement.

Corrigendum: Lymphangiographic Interventions to Manage Postoperative Chylothorax.

[This corrects the article on p. 409 in vol. 52, PMID: 31832377.].

Videoscopic Surgery for Arteriovenous Hemodialysis Access.

BACKGROUND: When an arteriovenous fistula (AVF) is created using the basilic or deep cephalic vein, it is additionally necessary to transfer the vessels to a position where needling is easy; however, many patients develop wound-related postsurgical complications due to the long surgical wounds resulting from conventional superficialization of a deep AVF or basilic vein transposition. Thus, to address this problem, we performed videoscopic surgery with small surgical incisions. METHODS: Data from 16 patients who underwent additional videoscopic radiocephalic superficialization, brachiocephalic superficialization, and brachiobasilic transposition after AVF formation at our institution in 2018 were retrospectively reviewed. RESULTS: Needling was successful in all patients. No wound-related complications occurred. The mean vessel size and blood flow of the AVF just before the first needling were 0.73±0.16 mm and 1,516.25±791.26 mL/min, respectively. The mean vessel depth after surgery was 0.26±0.10 cm. Percutaneous angioplasty was additionally performed in 25% of the patients. Primary patency was observed in 100% of patients during the follow-up period (262.44±73.49 days). CONCLUSION: Videoscopic surgery for AVF dramatically reduced the incidence of postoperative complications without interrupting patency; moreover, such procedures may increase the use of native vessels for vascular access. In addition, dissection using a videoscope compared to blind dissection using only a skip incision dramatically increased the success rate of displacement by reducing damage to the dissected vessels.

Lymphangiographic Interventions to Manage Postoperative Chylothorax.

BACKGROUND: Postoperative chylothorax may be caused by iatrogenic injury of the collateral lymphatic ducts after thoracic surgery. Although traditional treatment could be considered in most cases, resolution may be slow. Radiological interventions have recently been developed to manage postoperative chylothorax. This study aimed to compare radiological interventions and conservative management in patients with postoperative chylothorax. METHODS: We retrospectively reviewed periprocedural drainage time, length of hospital stay, and nil per os (NPO) duration in 7 patients who received radiological interventions (intervention group [IG]) and in 9 patients who received conservative management (non-intervention group [NG]). RESULTS: The baseline characteristics of the patients in the IG and NG were comparable; however, the median drainage time and median length of hospital stay after detection of chylothorax were significantly shorter in the IG than in the NG (6 vs. 10 days, p=0.036 and 10 vs. 20 days, p=0.025, respectively). NPO duration after chylothorax detection and total drainage duration were somewhat shorter in the IG than in the NG (5 vs. 7 days and 8 vs. 14 days, respectively). CONCLUSION: This study showed that radiological interventions reduced the duration of drainage and the length of hospital stay, allowing an earlier return to normal life. To overcome several limitations of this study, a prospective, randomized controlled trial with a larger number of patients is recommended.

Tunable Properties of MAPLE-Deposited Thin Films in the Presence of Suppressed Segmental Dynamics.

Processing polymer thin films by physical vapor deposition has been a major challenge due to material degradation. This challenge has limited our understanding of morphological control by top-down approaches that can be crucial for many applications. Recently, matrix-assisted pulsed laser evaporation (MAPLE) has emerged as an alternative route to fabricate polymer thin films from near-gas phase growth conditions. In this Letter, we investigate how this approach can result in a stable two-phase film structure of semicrystalline polymers via a unique combination of MAPLE and flash calorimetry. In the case of MAPLE-deposited poly(ethylene oxide) (PEO) thin films, we find a 35 °C enhancement in the glass transition temperature relative to melt-crystallized films, which is associated with irreversible chain adsorption in the amorphous region of the film. Remarkably, by varying substrate temperature during deposition, we reveal the ability to significantly tune the crystal orientation, extent of crystallinity, and lamellar thickness of MAPLE-deposited PEO thin films.

Photoluminescence of Functionalized Germanium Nanocrystals Embedded in Arsenic Sulfide Glass.

Embedding metallic and semiconductor nanoparticles in a chalcogenide glass matrix effectively modifies the photonic properties. Such nanostructured materials could play an important role in optoelectronic devices, catalysis, and imaging applications. In this work, we fabricate and characterize germanium nanocrystals (Ge NCs) embedded in arsenic sulfide thin films by pulsed laser ablation in aliphatic amine solutions. Unstable surface termination of aliphatic groups and stable termination by amine on Ge NCs are indicated by Raman and Fourier-transform infrared spectroscopy measurements. A broad-band photoluminescence in the visible range is observed for the amine functionalized Ge NCs. A noticeable enhancement of fluorescence is observed for Ge NCs in arsenic sulfide, after annealing to remove the residual solvent of the glass matrix.

Irreversible Adsorption Controls Crystallization in Vapor-Deposited Polymer Thin Films.

Matrix-assisted pulsed laser evaporation (MAPLE) provides a gentle means for the quasi-vapor deposition of macromolecules. It offers a unique opportunity for the bottom-up control of polymer crystallization as film growth and crystallization occur simultaneously. Surprisingly, with increasing deposition time, it has been shown that crystallization becomes prohibited despite the availability of polymer via continuous deposition. In this Letter, we investigate the molecular origins of suppressed crystallization in poly(ethylene oxide) films deposited by MAPLE atop silicon substrates. We find that suppressed crystallization results from the formation of an irreversibly adsorbed polymer nanolayer at the substrate that forms during deposition. Substrate temperature is shown to influence the stability of the irreversibly adsorbed nanolayer and, hence, polymer thin film crystallization. Our investigation offers new insight into how temperature and interfacial interactions can serve as a new toolbox to tune polymer film morphology in bottom-up deposition.

Hybrid-type quantum-dot cosensitized ZnO nanowire solar cell with enhanced visible-light harvesting.

A polymer hybrid quantum-dot-sensitized solar cell was developed using CdSe/CdS/ZnO nanowires as a photoanode and regioregular P3HT as a conjugated polymer. The P3HT polymer was used as a hole transport material to replace the liquid electrolyte in quantum dot sensitized solar cells, CdSe/CdS acts as a cosensitizer, which enhances light harvesting in the visible range, and the ZnO nanowires provide a direct pathway for electron transport. Through an adequate cascade bandgap structure of the photoanode, the photoexcited electrons were effectively separated from the electron/hole pairs and transported under illumination. The remaining holes at the anode were transported by the conjugated polymer P3HT without any intermediate potential loss. The fabrication of the hybrid solar cell was optimized with various experimental conditions, including the length of the ZnO nanowires, quantum sensitizers, P3HT filling conditions, and electrolytes. The optimally obtained hybrid solar cells exhibited 1.5% power-conversion efficiency under AM 1.5G of 100 mW/cm(2) intensity. The fabricated hybrid cells exhibited highly durable cell performances, even after 1 month under atmospheric conditions, whereas the liquid junction quantum dot sensitized solar cells exhibited a significant degradation in their performances during the first 2 weeks immediately after fabrication. High open-circuit voltage and fill factor values of our hybrid quantum-dot-sensitized solar cell indicate that the applied hole transport layer efficiently dissociates electron/hole pairs at the interface and retards the interfacial charge recombination.