B Cell-Derived Extracellular Vesicles Reveal Residual B Cell Activity in Kidney Graft Recipients Undergoing Pre-Transplant Desensitization

Background: Living-donor kidney transplant (LDKT) recipients undergoing desensitization for Human Leukocyte Antigen (HLA)-incompatibility have a high risk of developing antibody-mediated rejection (ABMR). The purpose of the study is to evaluate if residual B cell activity after desensitization could be estimated by the presence of circulating B cell-derived extracellular vesicles (BEVs).Methods: BEVs were isolated by Sepharose-based size exclusion chromatography and defined as CD19+ and HLA-II+ extracellular vesicles. We analyzed stored serum samples from positive crossmatch LDKT recipients before and after desensitization at first post-transplant biopsy and at 12-month protocol biopsy (n = 11). Control groups were formed by hypersensitized patients who were not submitted to desensitization (n = 10) and by low-risk recipients (n = 9). A prospective validation cohort of 11 patients also included the analysis of B cells subpopulations in recipients' blood and lymph nodes recovered upon graft implantation, along with BEVs analysis before and after desensitization.Results: We found out that CD19+ and HLA-II+BEVs dropped significantly after desensitization and relapse in patients who later developed ABMR was evident. We validated these findings in a proof-of-concept prospective cohort of 6 patients who received the same desensitization protocol and also in a control group of 5 LDKT recipients. In these patients, B cell subpopulations were also studied in recipients' blood and lymph nodes that were recovered before the graft implantation. We confirmed the significant drop in BEVs after desensitization and that this paralleled the reduction in CD19+cells in lymph nodes, while in peripheral blood B cells, this change was almost undetectable.Conclusions: BEVs reflected B cell residual activity after desensitization and this could be a valid surrogate of humoral alloreactivity in this setting.

Hemodialysis Reliable Outflow (HeRO) graft creation in upper extremities abandoned due to stent obstruction via recanalization and HeRO outflow component insertion across stent interstices

Background: The purpose of this study was to assess the feasibility and outcomes of recanalization and subsequent HeRO graft outflow component insertion across stent interstices in patients with an otherwise abandoned upper extremity. Methods: Over a 10-year period, 15 patients underwent central venous recanalization by interventional radiology across the interstices of one or more occluded stents for the purpose of subsequent HeRO graft creation. A tunneled central venous catheter was left across the stent and occlusions with tip in right atrium. On a later date, the catheter was used for rapid guidewire access for HeRO graft implantation in the OR by vascular surgery. Procedural and clinical outcomes were determined by retrospective review. Primary and secondary HeRO graft patency rates were estimated with the Kaplan-Meier technique. Results: The technical success rates of recanalization across stent interstices was 100% (15/15). Between one and four overlapping stent walls were traversed. The technical success of the patients who underwent attempted HeRO graft implantation with outflow component traversing across stent interstices was 91% (11/12). No major complications were encountered with either recanalization or HeRO graft implantation. The primary and secondary HeRO patency rates at 12 months were 64% and 80%, respectively. Conclusion: HeRO graft insertion across stent interstices is feasible and can provide effective permanent AV access; thus, the presence of stents across the subclavian and brachiocephalic veins should not be considered a contraindication.

Safety and Efficacy of Stent Graft Implantation for Malignant Superior Vena Cava Syndrome

Background: Patients with malignant superior vena cava syndrome (SVCS) usually require urgent treatments due to a high potential risk of early mortality. Stent implantation can rapidly improve the symptoms of SVCS, which may be beneficial to subsequent anti-tumor therapy. The aim of the study was to evaluate the clinical outcomes of stent graft implantation for the treatment of superior vena cava (SVC) obstruction caused by non-small cell lung carcinoma (NSCLC) with acute post-stenting occlusion. Methods: Between October 2014 and December 2019, 16 patients were selected for stent graft implantation. Technical success and clinical efficacy were assessed. Stent patency and patient survival rates, as well as the complications were analyzed. Results: There were 17 stent grafts implanted in 16 patients. The technical success was 100%. The residual stenosis after initial implantation was 64.0 ± 9.0%. The stent expanded to an optimal size in 5.5 ± 2.2 days after the initial deployment. Migration occurred when deploying of the stent graft in one patient; this stent graft was successfully stabilized by a second one. No other complications related to the procedure were found except one migration. At 1, 3, 6, 9 and 12 months, the cumulative survival rates were 100%, 75%, 56%, 19% and 0%, respectively. The mean OS was 173 days. The median survival was 166 days. Conclusions: Stent graft can be safely used in patients with SVC obstruction with a good long-term patency rate.

Stent Graft Placement by Pseudoaneurysm of the Hepatic Arteries: Efficacy and Patency Rate in Follow-up

Purpose To investigate efficacy and patency status of stent graft implantation in the treatment of hepatic artery pseudoaneurysm. Materials and Methods A retrospective analysis of patients who had undergone endovascular treatment of hepatic artery pseudoaneurysms between 2011 and 2020 was performed. Medical records were examined to obtain patients’ surgical histories and to screen for active bleeding. Angiographic data on vascular access, target vessel, material used and technical success, defined as the exclusion of the pseudoaneurysm by means of a stent graft with sufficient control of bleeding, were collected. Vessel patency at follow-up CT was analyzed and classified as short-term (< 6 weeks), mid-term (between 6 weeks and 1 year), and long-term patency (> 1 year). In case of stent occlusion, collateralization and signs of hepatic hypoperfusion were examined. Results In total, 30 patients were included and of these, 25 and 5 had undergone stent graft implantation and coiling, respectively. In patients with implanted stent grafts, technical success was achieved in 23/25 patients (92%). Follow-up CT scans were available in 16 patients, showing stent graft patency in 9/16 patients (56%). Short-term, mid-term, and long-term short-term stent patency was found in 81% (13/16), 40% (4/10), and 50% (2/4). In patients with stent graft occlusion, 86% (6/7) exhibited maintenance of arterial liver perfusion via collaterals and 14% (1/7) exhibited liver abscess during follow-up. Conclusion Stent graft provides an effective treatment for hepatic artery pseudoaneurysms. Even though patency rates decreased as a function of time, stent occlusion was mainly asymptomatic due to sufficient collateralization.

Stent-graft and double-guiding catheter technique to rescue iatrogenic coronary perforation

IntroductionCoronary artery perforation (CAP) is an infrequent, yet life-threatening complication of percutaneous coronary interventions, posing a major risk of cardiac tamponade and mortality.Material and methodsWe report on effective management of Ellis type III CAP with use of double-guiding catheter technique and stent-graft implantation.ResultsProlonged balloon inflation via the first guiding catheter allows for temporary closure of the bleeding site. At the same time, stent-graft is inserted via the second guiding catheter to seal the perforation. After rapid deflation of the balloon, the stent is immediately advanced and expanded.ConclusionsThe procedure minimises the time between deflation of the balloon and implantation of the stent-graft, allowing for successful bleeding cessation.