Patch Venoplasty Research Articles

Temporary mesenteric venous shunting for portal vein reconstruction: A novel technical adjunct

Pancreatic resection not infrequently requires portal vein (PV) repair or replacement. PV reconstruction often requires bypass grafting or patch venoplasty, and these grafts and patches require time to thaw or harvest. Mesenteric ischemia and congestion with associated bowel edema may result from prolonged venous occlusion during thawing, harvesting, and reconstructing. Temporary shunting of the mesenteric venous circulation may mitigate these adverse effects. Twenty-one patients were shunted using Argyle shunts during PV reconstruction from 2010 to 2020. Reconstructions in this series consisted of aortic homograft interposition grafts (52%), bovine pericardial patches (38%), internal jugular vein interposition grafts (5%), and internal jugular patches (5%). No intraoperative complications resulted from shunt placement; technical success of PV reconstruction was 100%. Temporary venous shunting during PV reconstruction is safe, technically straightforward, and may serve to decrease the duration of venous mesenteric occlusion.

Surgical treatment of Nutcracker Syndrome

The objective of this paper is to report early and mid-term outcomes of the surgical treatment Nutcracker Syndrome (NCS) in a single-center prospective study. Between January 2019 and September 2023, five patients with symptomatic NCS were treated at our center using left renal vein caudal transposition on the inferior vena cava, conducted through a midline incision of approximately 12 cm and a transperitoneal technique. Patient characteristics, presentation, length of hospital stay, and complications were analyzed. All diagnoses were established after clinical evaluation, ultrasound scanning, and radiological investigations, which confirmed left renal vein compression between the aorta and the Superior Mesenteric Artery (SMA). The average operating time was 159 minutes, with an average blood loss of 205 mL. There was no need for blood transfusions. Intensive care stay was not required and there were no early complications. The mean length of stay was 3.5 days. At a mean follow-up of 18.8 months, one patient reported persistent hematuria, and therefore underwent a secondary procedure, which incorporated patch venoplasty using the great saphenous vein. In our experience, left renal vein transposition appears to be a safe and effective procedure for the surgical management of severe NCS.

Silver Ion Decreases Foreign Body Reaction and Venous Neointimal Hyperplasia through the Inhibition of Interleukin-33 Expression

Introduction: Vascular prosthetic grafts are widely used in vascular surgery; however, graft infection remains a major concern. Silver-coated vascular grafts have demonstrated anti-infection properties in clinical settings; however, whether the silver irons influence foreign body reaction or neointimal hyperplasia remains unclear. Methods: Sodium alginate and hyaluronic acid (SA/HA) hydrogel patches loaded with rhodamine, with or without silver, were fabricated. Patches were implanted in the subcutaneous or abdominal cavity and inferior vena cava of rats. Samples were harvested on day 14 and examined via immunohistochemical and immunofluorescence analyses. Results: Silver hydrogel was found to decrease the foreign body reaction; after subcutaneous and abdominal cavity implantation in rats, the capsule was found to be thinner in the silver hydrogel group than in the control hydrogel group. The silver hydrogel group had fewer CD68-positive cells and proliferating cell nuclear antigen and interleukin-33 (IL-33) dual-positive cells than the control hydrogel group. Additionally, the silver hydrogel patch reduced the neointimal thickness after patch venoplasty in rats, and the number of IL-33- and IL-1β-positive cells was lower than that in the control patch. Conclusion: Silver-loaded SA/HA hydrogel patches decreased the foreign body reaction and venous neointimal hyperplasia in rats by the inhibition of IL-33 expression.

Portal vein wedge resection and patch venoplasty with autologous vein grafts for hepatobiliary–pancreatic cancer

BackgroundAdvanced hepatobiliary–pancreatic cancer often invades critical blood vessels, including the portal vein (PV) and hepatic artery. Resection with tumor-free resection margins is crucial to achieving a favorable prognosis in these patients. Herein, we present our cases and surgical techniques for PV wedge resection with patch venoplasty using autologous vein grafts during surgery for pancreatic ductal adenocarcinoma (PDAC) and perihilar cholangiocarcinoma (PhCC).Case presentationCase 1: 73-year-old female patient with PDAC; underwent subtotal stomach-preserving pancreatoduodenectomy, with superior mesenteric vein wedge resection and venoplasty with the right gonadal vein. Case 2: 67-year-old male patient with PDAC; underwent distal pancreatectomy and celiac axis resection, with PV wedge resection and venoplasty with the middle colic vein. Case 3: 51-year-old female patient with type IV PhCC; underwent left hepatectomy with caudate lobectomy and bile duct resection, with hilar PV wedge resection and venoplasty with the inferior mesenteric vein (IMV). Case 4: 69-year-old male patient with type IIIA PhCC; underwent right hepatopancreatoduodenectomy, with hilar PV resection and patch venoplasty with the IMV. All patients survived for over 12 months after the surgery, without local recurrence.ConclusionsPV wedge resection and patch venoplasty is a useful technique for obtaining tumor-free margins in surgeries for hepatobiliary–pancreatic cancer.

Management of concomitant central venous disease.

Symptomatic central venous disease (CVD) is a significant common problem in patients with end-stage renal disease given its adverse impact on hemodialysis (HD) vascular access (VA). The current mainstay management is percutaneous transluminal angioplasty (PTA) with or without stenting which is typically reserved for unsatisfactory angioplasty or more challenging lesions. Despite factors such as target vein diameters and lengths and vessel tortuosity that may determine the choice of bare-metal versus covered stents (CS), current scientific literature is pointing out the superiority of the latter one. Alternative management options such as hemodialysis reliable outflow (HeRO) graft showed favorable results in terms of high patency rates and fewer infections, however, complications such as a steal syndrome and, to a lesser extent, graft migration and separation are major concerns. The surgical reconstruction approaches such as bypass, patch venoplasty, or chest wall arteriovenous graft with or without endovascular interventions as a hybrid procedure are still viable options and may be considered. However, further long-term investigations are needed to highlight the comparative outcomes of these approaches. Open surgery might be an alternative before proceeding to more unfavorable approaches such as lower extremity vascular access (LEVA). The appropriate therapy should be selected based upon a patient-centered interdisciplinary discussion utilizing the locally available expertise in the area of VA creation and maintenance.

Delivery of rivaroxaban and chitosan rapamycin microparticle with dual antithrombosis and antiproliferation functions inhibits venous neointimal hyperplasia

Neointimal hyperplasia is a complex process after vascular interventions, acute platelet deposition and smooth muscle cell proliferation both contributed to this process. There are still no perfect solutions to solve this problem. Rivaroxaban is a novel anticoagulant that has been widely used in clinic, it has a good pharmacological effects both in vivo and in vitro. Chitosan microparticle rapamycin (MP-rapa) was fabricated, interspaces of polyglycolic acid (PGA) scaffold were used as a reservoir of MP-rapa, and the scaffold was coated with hyaluronic acid rivaroxaban (MP-rapa-riva). Scanning electronic microscopy (SEM) photographs were taken and water contact angles were measured, rat inferior vena cava (IVC) patch venoplasty model was used; patches were harvested at day 14 and examined by immunohistochemistry and immunofluorescence. SEM photographs showed the microparticles rapamycin were inside the interspace of the scaffold, hyaluronic acid rivaroxaban was also successfully coated onto the surface of the scaffold. There was a thinner neointima, fewer proliferating cell nuclear antigen (PCNA) positive cells, fewer macrophages in the MP-rapa and MP-rapa-riva grafts compared to the control PGA graft. The result showed that this scaffold with dual anticoagulation and antiproliferation functions can effectively inhibit venous neointimal hyperplasia, although this is an animal experiment, it showed promising potential clinical application in the future.

Technical Refinement to Prevent Hepatic Outflow Disturbance in Right Lobe Living Donor Liver Transplantation: The New Simplified One-Orifice Venoplasty Technique

Middle hepatic vein (MHV) reconstruction is often essential to avoid hepatic congestion and serious graft dysfunction in living donor liver transplantation (LDLT). This article introduces the evolution of our MHV reconstruction technique and the excellent outcomes of a new simplified one-orifice venoplasty. We compared clinical outcomes among 3 types of one-orifice techniques through a retrospective review of 378 recipients who underwent LDLT using a modified right lobe graft at our institution from January 2008 to December 2018; group I (n=34) received separate outflow reconstruction, group II (n=166) received the one-orifice technique to create a wider single outflow with patchwork, and group III (n=178) received the more simplified one-orifice technique in which neo-MHV was reconstructed into the right hepatic vein without patch venoplasty. Patient demographic characteristics did not differ significantly among the 3 groups, but cold ischemic time and operative time in groups II and III were significantly shorter than those in group I. Moreover, the early patency rates of MHV in groups II and III were higher than those in group I. In particular, group I received an MHV or right hepatic vein stenting more frequently than group II or III during the early posttransplant period. In conclusion, this new simplified one-orifice technique could be an effective method to overcome technical difficulties and the outflow disturbance during right lobe LDLT without complex benchwork to create a large outflow.

Back Table Preparation of the Right Lobe Live Donor Liver Allograft: A Crucial Part of the Adult Live Donor Liver Transplant Procedure

IntroductionWe aimed to describe our procedure for vascular reconstruction and back table bench preparation for the right lobe live donor allograft. Live donor liver transplantation (LDLT) remains an important option for the expansion of the donor pool. The procedure has been widely used, and its success is dependent on a technically perfect operation with appropriate inflow and outflow of the allograft. Adequate preparation of the right lobe (RL) allograft prior to implantation remains a vital part of the procedure. MethodsOur technique of back table vascular reconstruction of the RL allograft has been performed using a hepatic vein patch venoplasty, inferior hepatic vein inclusion, portal vein reconstruction, and segment V and VIII reconstruction for all of our LDLTs. ResultsBetween March 2009 and January 2020, 321 consecutive adult LDLTs were performed and underwent back table reconstruction with the techniques described. During that time period, no patients had hepatic insufficiency. There was a single thrombosis of a superior mesenteric vein (SMV) to PV jump conduit. ConclusionsOur technique of back table reconstruction of the LDLT right lobe graft remains a crucial part of the operative procedure. Our experience with RL grafts without middle hepatic vein (MHV) and our systematic approach for inflow and outflow reconstruction has yielded excellent results with no technical outflow issues and minimal inflow complications.

Wood-Derived Vascular Patches Loaded With Rapamycin Inhibit Neointimal Hyperplasia.

Background: Patches are commonly used to close blood vessels after vascular surgery. Most currently used materials are either prosthetics or animal-derived; although natural materials, such as a leaf, can be used as a patch, healing of these natural materials is not optimal; rhodamine and rapamycin have been used to show that coating patches with drugs allow drug delivery to inhibit neointimal hyperplasia that may improve patch healing. Wood is abundant, and its stiffness can be reduced with processing; however, whether wood can be used as a vascular patch is not established. We hypothesized that wood can be used as a vascular patch and thus may serve as a novel plant-based biocompatible material. Method: Male Sprague–Dawley rats (aged 6–8 weeks) were used as an inferior vena cava (IVC) patch venoplasty model. After softening, wood patches coated with rhodamine and rapamycin were implanted into the rat subcutaneous tissue, the abdominal cavity, or the IVC. Samples were explanted on day 14 for analysis. Result: Wood patches became soft after processing. Patches showed biocompatibility after implantation into the subcutaneous tissue or the abdominal cavity. After implantation into the IVC, the patches retained mechanical strength. There was a significantly thinner neointima in wood patches coated with rapamycin than control patches (146.7 ± 15.32 μm vs. 524.7 ± 26.81 μm; p = 0.0001). There were CD34 and nestin-positive cells throughout the patch, and neointimal endothelial cells were Eph-B4 and COUP-TFII-positive. There was a significantly smaller number of PCNA and α-actin dual-positive cells in the neointima (p = 0.0003), peri-patch area (p = 0.0198), and adventitia (p = 0.0004) in wood patches coated with rapamycin than control patches. Piezo1 was expressed in the neointima and peri-patch area, and there were decreased CD68 and piezo1 dual-positive cells in wood patches coated with rapamycin compared to control patches. Conclusion: Wood can be used as a novel biomaterial that can be implanted as a vascular patch and also serve as a scaffold for drug delivery. Plant-derived materials may be an alternative to prosthetics or animal-based materials in vascular applications.

Biodegraded PCl and gelatin fabricated vascular patch in rat aortic and inferior vena cava angioplasty.

Novel synthetic prosthesis materials for patch angioplasty are continuously under development and optimization. When a nonwoven-based gelatin membrane is coupled with an electrospun layer of polycaprolactone (PCL), these biohybrid polymer membranes (BHMs) possess higher mechanical properties in aqueous environments. We hypothesized that BHMs can also be used as vascular patches, and we tested our hypothesis in a rat IVC venoplasty and aortic arterioplasty model. Patch venoplasty and arterioplasty were performed in SD rats (200g), the patches were harvested at day 14, and samples were analyzed by immunohistochemistry and immunofluorescence. The BHM patches were almost degraded, with few parts remaining after 14days. There was a line of CD34- and nestin-positive cells on the endothelium, with some cells were CD34 and nestin dual-positive, macrophages and leukocytes also participated in the patch healing process. There were PCNA-positive cells in the neointima and peri-patch area, with some cells were also PCNA and α-actin dual-positive. Arterial neointimal endothelial cells were Ephrin-B2- and dll-4-positive, and venous neointimal endothelial cells were Eph-B4- and COUP-TFII-positive. BHM shares a similar healing process like other patch materials, and BHM may have potential applications in vascular surgery.

Artificial Roofing for Recurrent Pulmonary Vein Stenosis

Pulmonary vein stenosis occurs in up to one-fifth of patients after repair of total anomalous pulmonary venous connection and carries a poor prognosis. Current options for repair include patch venoplasty, endovenectomy, and the “sutureless” (pericardial well) technique. Approaches to repair vary and may include combinations of these techniques, but data suggest that the sutureless technique is associated with less restenosis.1 Yet, the sutureless technique is not a panacea: 30% of patients with pulmonary vein stenosis will undergo reoperation or die within 2 years.

A three-layered hydrogel patch with hierarchy releasing of PLGA nanoparticle drugs decrease neointimal hyperplasia

Hydrogel is a nature scaffold that can degraded in animal body and can be used as a drug delivery system, we hypothesized that patch made of three layers of hydrogel with different PLGA nanoparticle drugs (bio-patch) can be used to decrease venous neointimal hyperplasia. Rat inferior vena cava (IVC) patch venoplasty model was used. Samples from rat IVC direct suture (DS), decellularized thoracic artery patch (TA) venoplasty and bovine pericardial patch (BPP) venoplasty were examined at day 14 after implantation. Sodium alginate and hyaluronic acid (SA/HA) hydrogel was used, three layers hydrogel patch (control) and three layers hydrogel patch with PLGA nanoparticle drugs (bio-patch) were used in rat IVC venoplasty. Patches were harvested at day 14 and analyzed. In rats, TA and BPP patch showed a thicker neointima and adventitia compared to the DS, there were larger numbers of CD68 and PCNA positive cells in both groups. The control hydrogel patch showed much thinner neointima and adventitia compared to TA and BPP patches. In both of the neointima and peri-patch area, bio-patch showed significantly fewer smooth muscle cells, fewer CD68, fewer PCNA positive cells, fewer collagen-1 positive cells, fewer p-smad2 positive cells, fewer TNF-α positive cells compared to control hydrogel patch. Bio-patch made of hydrogel and PLGA nanoparticle drugs showed a thinner neointimal thickness, and is biocompatible to the animal body. These results showed the potential application of hydrogel patch in vascular surgery.

Portal vein wedge resection and patch venoplasty using autologous and homologous vein grafts during surgery for hepatobiliary malignancies.

Obtaining tumor-free resection margins is one of the most important factors for achieving favorable prognosis of patients undergoing resection for hepatobiliary malignancies. In this study, we present our experience of portal vein (PV) wedge resection and patch venoplasty using autologous or homologous vessel grafts for resecting perihilar cholangiocarcinoma, hepatocellular carcinoma, and distal bile duct cancer. Case 1 was 68-year-old male patient with type IV perihilar cholangiocarcinoma who underwent central bisectionectomy with caudate lobectomy and bile duct resection, and PV wedge resection and patch venoplasty with a cryopreserved iliac vein allograft patch. This patient survived 14 months after surgery. Case 2 was 77-year-old male patient with type IIIA perihilar cholangiocarcinoma who underwent left medial sectionectomy with caudate lobectomy, bile duct resection, and PV wedge resection and patch venoplasty with a cryopreserved iliac vein allograft patch. This patient survived 17 months after surgery. Case 3 was 54-year-old male patient with hepatitis B virus-associated liver cirrhosis and hepatocellular carcinoma with PV tumor thrombus who underwent left hepatectomy. The PV wall defect was repaired with an autologous greater saphenous vein patch. This patient survived 11 months after surgery. Case 4 was 65-year-old female patient with distal bile duct cancer who underwent pylorus-preserving pancreaticoduodenectomy, and main PV wedge resection and patch venoplasty with a cryopreserved iliac artery allograft patch. This patient survived 21 months after surgery. In conclusion, PV wedge resection and patch venoplasty can be used to facilitate complete tumor resection in patients undergoing various extents of surgical resection for hepatobiliary malignancies.

A Novel Plant Leaf Patch Absorbed With IL-33 Antibody Decreases Venous Neointimal hyperplasia.

Introduction: We recently showed that a decellularized leaf scaffold can be loaded with polylactic-co-glycolic acid (PLGA)-based rapamycin nanoparticles, this leaf patch can then inhibit venous neointimal hyperplasia in a rat inferior vena cava (IVC) venoplasty model. IL-33 plays a role in the neointimal formation after vascular injury. We hypothesized that plant leaves can absorb therapeutic drug solution and can be used as a patch with drug delivery capability, and plant leaves absorbed with IL-33 antibody can decrease venous neointimal hyperplasia in the rat IVC venoplasty model. Method: A human spiral saphenous vein (SVG) graft implanted in the popliteal vein was harvested from a patient with trauma and analyzed by immunofluorescence. Male Sprague-Dawley rats (aged 6–8 weeks) were used to create the IVC patch venoplasty model. Plant leaves absorbed with rhodamine, distilled water (control), rapamycin, IL-33, and IL-33 antibody were cut into patches (3 × 1.5 mm2) and implanted into the rat IVC. Patches were explanted at day 14 for analysis. Result: At day 14, in the patch absorbed with rhodamine group, immunofluorescence showed rhodamine fluorescence in the neointima, inside the patch, and in the adventitia. There was a significantly thinner neointima in the plant patch absorbed with rapamycin (p = 0.0231) compared to the patch absorbed with distilled water. There was a significantly large number of IL-33 (p = 0.006) and IL-1β (p = 0.012) positive cells in the human SVG neointima compared to the human great saphenous vein. In rats, there was a significantly thinner neointima, a smaller number of IL-33 (p = 0.0006) and IL-1β (p = 0.0008) positive cells in the IL-33 antibody-absorbed patch group compared to the IL-33-absorbed patch group. Conclusion: We found that the natural absorption capability of plant leaves means they can absorb drug solution efficiently and can also be used as a novel drug delivery system and venous patch. IL-33 plays a role in venous neointimal hyperplasia both in humans and rats; neutralization of IL-33 by IL-33 antibody can be a therapeutic method to decrease venous neointimal hyperplasia.

Portal vein wedge resection and patch venoplasty using autologous and homologous vein grafts during surgery for hepatobiliary malignancies

Obtainment of tumor-free resection margins is one of the most important factors for favorable prognosis of patients undergoing resection for hepatobiliary malignancies. In this study, we present our experience of portal vein (PV) wedge resection and patch venoplasty using autologous or homologous vessel grafts used in resection for perihilar cholangiocarcinoma, hepatocellular carcinoma and distal bile duct cancer. Case 1: A 68-year-old male patient with type IV perihilar cholangiocarcinoma underwent central bisectionectomy with caudate lobectomy and bile duct resection, and PV wedge resection and patch venoplasty with a cryopreserved iliac vein allograft patch. This patient survived 14 months after surgery. Case 2: A 77-year-old male patient with type IIIA perihilar cholangiocarcinoma underwent left medial sectionectomy with caudate lobectomy and bile duct resection, and PV wedge resection and patch venoplasty with a cryopreserved iliac vein allograft patch. This patient survived 16 months after surgery. Case 3: A 54-year-old male patient with hepatitis B virus-associated liver cirrhosis and hepatocellular carcinoma with PV tumor thrombus underwent left hepatectomy. The PV wall defect was repaired with an autologous greater saphenous vein patch. This patient survived 11 months after surgery. Case 4: A 65-year-old female patient with distal bile duct cancer underwent pylorus-preserving pancreaticoduodenectomy and main PV wedge resection and patch venoplasty with a cryopreserved iliac artery allograft patch. This patient survived 21 months after surgery. In conclusion, PV wedge resection and patch venoplasty provide a useful option to facilitate complete tumor resection in patients undergoing various extents of surgical resection for hepatobiliary malignancies.

Standard and modified techniques for parenchyma-preserving hepatectomy focused on segments I + IV resection in patients with perihilar cholangiocarcinoma

Resection of the hepatic segments I + IV (S1 + S4) is the most common type of parenchyma-preserving hepatectomy (PPH) for perihilar cholangiocarcinoma (PHCC). We describe our experience on the standard and modified techniques for PPH focused on S1 + S4 resection in patients with PHCC. 1) Isolated caudate lobectomy with bile duct resection (BDR) is the minimal type of PPH, but not currently recommended due to technical difficulty. 2) Partial hepatectomy of S1 + S4a ± segment V (S5) with BDR provides wide operative field, but extension of BDR is limited and resection of S1 paracaval portion is still difficult. 3) Resection of S1 + S4 + S5 with BDR provides wider operative field for complete S1 resection and multiple biliary reconstruction. 4) Resection of S1 + S4 with BDR offers very wide operative field and allows wider extent of hilar BDR, and thus presents the most common type of PPH. A supplementary video clip presents the detailed standard surgical procedure for resection of S1 + S4 with BDR in a patient with type IIIA PHCC. 5) Modified resection of S1 + S4 ± S5 or segment VIII (S8) with BDR facilitates additional resection of tumor-involved S5 or S8 ducts. 6) Major hilar vascular invasion is usually contraindicated for PPH and only small portal vein invasion requiring wedge resection and patch venoplasty is allowed. In conclusion, PPH can achieve curative resection and improved outcomes in patients with PHCC via reasonable modification of the extent of hepatectomy and hilar BDR. PPH may have advantages in selected patients depending on the extent of tumor, and in patients with high operative risk.

Standard radical bile duct surgery focused on vascular reconstruction

Since the mid bile duct cancers often involve the intrapancreatic bile duct, resection of the extrahepatic bile duct results in a tumor-positive distal resection margin. Extended extrahepatic bile duct resection is a surgical procedure to obtain a tumor-free distal resection margin during extrahepatic bile duct resection, in which R0 resection can be achieved without performing pancreatoduodenectomy. The extent of intrapancreatic bile duct excavation was designed to resemble making a several cm-long funnel. The surgical procedure for pancreatic excavation was derived from those used for choledochal cyst excision. Special attention should be paid to prevent pancreatic leak at the bile duct excavation portion at the pancreatic head. If the proximal extrahepatic bile duct is tumor-positive, major or parenchyma-preserving hepatectomy is necessary to achieve R0 resection. Resection of segment I and segment IV with bile duct resection offers very wide operative field and allows wider extent of hilar bile duct resection, thus presents the most common type of parenchyma-preserving hepatectomy. When the portal vein is focally involved by the tumor, hilar portal vein wedge resection and roofing patch venoplasty using a autograft or homograft vein patch is a useful option to facilitate complete tumor resection in patients undergoing bile duct resection. Regarding roofing patch venoplasty, it is important to make the portal vein wall defect as small as possible as well as to make the size of the vein patch either twice or three times larger than the defect size at the portal vein wall. The patch should be large enough to make the patch roof redundant. Even if the patch roof appears to be noticeably redundant at the time of operation, it is vulnerable to shrinkage due to compression of the jejunal loop and through degenerative changes of the patch per se. The availability of vein autografts or homografts facilitates combined vascular resection and reconstruction during aggressive surgery for hepatobiliary malignancies.

Programmed death-1 mediates venous neointimal hyperplasia in humans and rats

Venous neointimal hyperplasia can be a problem after vein interventions. We hypothesized that inhibiting programmed death-1 (PD-1) can decrease venous neointimal hyperplasia in a rat inferior vena cava (IVC) patch venoplasty model. The rats were divided into four groups: the control group was only decellularized without other special treatment; the PD-1 group was injected with a single dose of humanized PD-1 antibody (4 mg/kg); the PD-1 antibody coated patches group; the BMS-1 (a PD-1 small molecular inhibitor) coated patches group (PD-1 inhibitor-1). Patches were implanted to the rat IVC and harvested on day 14 and analyzed. Immunohistochemical analysis showed PD-1-positive cells in the neointima in the human samples. There was high protein expression of PD-1 in the neointima in the rat IVC venoplasty model. PD-1 antibody injection can significantly decrease neointimal thickness (p < 0.0001). PD-1 antibody or BMS-1 was successfully conjugated to the decellularized rat thoracic artery patch by hyaluronic acid with altered morphology and reduced the water contact angle (WCA). Patches coated with humanized PD-1 antibody or BMS-1 both can also decrease neointimal hyperplasia and inflammatory cells infiltration. PD-1-positive cells are present in venous neointima in both human and rat samples. Inhibition of the PD-1 pathway may be a promising therapeutic strategy to inhibit venous neointimal hyperplasia.

Application of the Tissue-Engineered Plant Scaffold as a Vascular Patch.

Tissue-engineered plant scaffolds have shown promising applications in in vitro studies. To assess the applicability of natural plant scaffolds as vascular patches, we tested decellularized leaf and onion cellulose in a rat inferior vena cava patch venoplasty model. The leaf was decellularized, and the scaffold was loaded with polylactic-co-glycolic acid (PLGA)-based rapamycin nanoparticles (nanoparticles). Nanoparticle-perfused leaves showed decreased neointimal thickness after implantation on day 14; there were also fewer CD68-positive cells and PCNA-positive cells in the neointima in the nanoparticle-perfused patches than in the control patches. Onion cellulose was decellularized, coated with rapamycin nanoparticles, and implanted in the rat; the nanoparticle-coated onion cellulose patches also showed decreased neointimal thickness. These data show that natural plant-based scaffolds may be used as novel scaffolds for tissue-engineered vascular patches. However, further modifications are needed to enhance patch strength for artery implantations.

The secondary patency after patch venoplasty versus balloon venoplasty in management of neointimal hyperplasia of the venous anastomosis of thrombosed arteriovenous grafts for hemodialysis

Background The pathogenesis of neointimal hyperplasia associated with hemodialysis arteriovenous (AV) grafts is complex and likely involves surgical manipulation of the tissues, material biocompatibility, and mechanical factors. Both surgical and radiological interventions for stenosed and thrombosed AV graft have been described aiming at the optimal restoration of morphology and function. Aim To compare the secondary patency after patch venoplasty and balloon venoplasty in management of neointimal hyperplasia of the venous anastomosis of AV graft for dialysis. Patients and methods This is a double-armed randomized prospective study that was carried out at Ain Shams University hospitals for 2 years. A total of 20 patients with thrombosed synthetic AV graft were enrolled in this study. The first group (10 patients) was treated with patch venoplasty, and the second group (10 patients) with balloon venoplasty adjunctive after surgical thrombectomy. Results Graft patency at 6-month and 12-month follow-up was 90 and 70% for the balloon angioplasty group versus 60 and 40% for the surgical patch venoplasty group (P=0.3 and 0.37, respectively). Conclusion In the present study, the outcome of balloon venoplasty was better than and patch venoplasty for thrombosed AV grafts. In addition to better graft patency, balloon venoplasty offers the advantage of shorter operative time and lower morbidity. Further studies with a large sample size and multicentric cooperation are required to confirm the present findings.