Experimental study of a heparin-coated venous stent fabricated by atomic layer deposition.

OBJECTIVE: To evaluate the safety and efficacy of heparin-coated venous stents in animals. METHODS: We used atomic layer deposition technology to obtain a heparin coating with good stability and then prepared a heparin-coated venous stent based on this technology. The experimental stents were prepared according to the diameter of the rabbit inferior vena cava and were divided into Ni-Ti alloy stent group, Ni-Ti-Al2O3 stent group and Ni-Ti-Al2O3-Heparin stent group. 3 days, 7 days and 14 days after stent implantation, the materials were collected, and the three groups of stents were observed by hard tissue section pathology, immunohistochemistry and scanning electron microscope to observe the differences in vascular wall inflammation, thrombosis, lumen stenosis and vascular intima regeneration. RESULT AND CONCLUSION: The experiment confirmed the safety of the heparin-coated stent in vivo. Compared with the control group, the experimental group showed a high degree of vascular endothelialization and an intact neointimal structure 14 days after implantation. The long-term safety and biological effects of heparin-coated venous stents in animals require further study.

In situ repair or reconstruction of the abdominal aorta-iliac artery by autologous fascia-peritoneum with posterior rectus sheath for the treatment of the infected abdominal aortic and iliac artery aneurysms: A case series and literature review.

Background: Infected abdominal aortic and iliac artery aneurysms are considered acute and severe diseases with insidious onset, rapid development, and high mortality in vascular surgery. Currently, there is no better treatment, either anatomic or extra-anatomical repair. Case presentation: From February 2018 to April 2022, 7 patients with infected abdominal aortic and iliac artery aneurysms did not have sufficient autologous venous material for repair. With the consent of the Ethics Committee of the hospital, it uses the autologous peritoneal fascial tissue with rectus sheath to repair or reconstruct the infected vessels in situ. There were 5 cases of infected abdominal aortic aneurysm, 1 case of an infected common iliac aneurysm, and 1 case of the infected internal iliac aneurysm. Aortoduodenal fistula was found in 3 cases, all of them were given duodenal fistula repair and gastrojejunostomy and cholecystostomy. Three cases of infected abdominal aortic aneurysms were repaired with the autologous peritoneal fascial tissue patch, and 2 cases of infected abdominal aortic aneurysms were reconstructed by the autologous peritoneal fascial tissue suture to bifurcate graft in situ, the autologous peritoneal fascial tissue suture reconstructed the rest 2 cases of infected iliac aneurysm to tubular graft in situ. It was essential that Careful debridement of all infected tissue and adequate postoperative irrigation and drainage. Antibiotics were administered perioperatively, and all patients were subsequently treated with long-term antibiotics based on bacterial culture and susceptibility results of infected tissues and blood. All 7 patients had underwent surgery successfully. But there were 2 cases died of anastomotic infection or massive hemorrhage after the operation, the other 5 cases survived. The follow-up time was 2-19 months. The enhanced CT of postoperation showed that the reconstructed arteries were smooth without obvious stenosis or expansion, and no abdominal wall hernia occurred. Conclusion: In situ repair or reconstruction with autologous peritoneal fascial tissue with rectus sheath is a feasible treatment for the infected aneurysm patients without adequate autologous venous substitute, but it still needs long-term follow-up and a large sample to be further confirmed.

Association Between Metformin and Abdominal Aortic Aneurysm: A Meta-Analysis.

Objective: To systematically examine the association between metformin and abdominal aortic aneurysm (AAA) and provide a basis for the treatment of AAA. Methods: Pubmed, Embase, Cochrane Library, and Ovid databases were searched by computer to identify the literature related to metformin and AAA published until February 2022. The literature was screened according to the inclusion and exclusion criteria, data were extracted, and a quality assessment was conducted. The meta-analysis was performed using Stata 16.0 and RevMan 5.3 software. Results: Seven articles containing a total of 10 cohort studies (85,050 patients) met the inclusion criteria and were included in the review. Meta-analysis showed that metformin can limit the expansion of AAA (MD = - 0.72, 95% CI: - 1.08 ~ -0.37, P < 0.00001), as well as reduce AAA repair or AAA rupture-related mortality (OR = 0.80, 95% CI:0.66 ~ 0.96, P = 0.02). The difference was statistically significant (P < 0.05). Conclusion: Metformin can limit the expansion of AAA and reduce the incidence of AAA and postoperative mortality. However, further biological experiments and clinical trials still need to be conducted to support this.

In situ reconstruction of ruptured mycotic iliac artery aneurysm with autologous fascial-peritoneal tissue: a case report and literature review.

BACKGROUND: Infectious aneurysms are rare in clinic with poor therapeutic outcomes. When artery rupture occurs, the disease tends to progress resulting in a high mortality, and there remains no ideal treatment. CASE PRESENTATION: We report a case of rupture of infectious iliac artery pseudoaneurysm, who was assigned to receive artery reconstruction with autologous fascial-peritoneal tissue and obtained satisfied short-term outcome. The follow-up of 6 months after operation was good and long-term follow-up is continuing. CONCLUSION: The posterior rectus fascia-peritoneal layer seems to be a feasible autologous biomaterial for vascular substitution in urgent setting when no other autologous material was available.

Neutrophil Gelatinase-Associated Lipocalin as an Early Predictor of Contrast-Induced Nephropathy Following Endovascular Aortic Repair for Abdominal Aortic Aneurysm.

To investigate serum neutrophil gelatinase-associated lipocalin (sNGAL) and urine neutrophil gelatinase-associated lipocalin (uNGAL) as early predictors of contrast-associated acute kidney injury(contrast-induced nephropathy)following endovascular aortic repair for abdominal aortic aneurysm. Prospective cohort study. Subjects included 202 consecutive patients with abdominal aortic aneurysm diagnosed between February 2016 and October 2018. We divided the patients into 2 groups: contrast-induced nephropathy (CIN) (n = 26) and non-CIN (n = 176). We assessed correlations between sNGAL and uNGAL concentrations and standard renal markers at baseline, 6, 24, and 48 hours post-procedure. We constructed conventional receiver operating characteristic (ROC) curves and calculated the area under the curve to assess SCr, eGFR, sNGAL, and uNGAL performance. We derived biomarker cutoff levels from ROC analysis results to maximize sensitivity and specificity values. The CIN incidence within our cohort was 12.9%. sNGAL levels correlated significantly with SCr and eGFR at baseline, 6, and 24 hours post-contrast medium exposure. Similarly, uNGAL levels correlated with SCr and estimated glomerular filtration rate (eGFR) at baseline, 6, and 24 hours post-exposure. sNGAL and uNGAL were significantly elevated as early as 6 hours post-endotherapy in the CIN group; there were only minor changes in the non-CIN group. SCr was also significantly elevated in the CIN group, but not until 48 hours post-catheterization. Both sNGAL and uNGAL may be more accurate than SCr and eGFR as early biomarkers of CIN in patients with abdominal aortic aneurysm undergoing endovascular therapy.

Guidance of Venous Stent Implantation after Catheter-directed Thrombosis in Patients with Acute Left Lower Extremity Deep Venous Thrombosis based on Pressure Gradient Differences between the Iliac Vein and Inferior Vena Cava: A Single-center Retrospective Study.

BACKGROUND: Iliac vein compression syndrome (IVCS) can lead to acute deep venous thrombosis (DVT) and post-thrombotic syndrome (PTS). Endovascular venous stenting has become a preferred treatment for IVCS. In this article, we guide stent implantation by the pressure gradient of iliac vein and inferior vena cava. To evaluate the feasibility of guidance of venous stent implantation based on venous pressure gradient difference. METHODS: A retrospective analysis was performed on patients with acute left lower extremity DVT who were treated in our center from March 2012 to December 2017. The patients were divided into 2 groups: group 1: from January 2015 to December 2017, patients were treated with catheter-directed thrombolysis (CDT) and stent implantation was guided by the pressure gradient of iliac vein and inferior vena cava after thrombectomy; group 2: from May 2012 to December 2014, patients underwent CDT treatment without stent implantation. In group 1, the patients were divided into 2 groups according to the difference in pressure gradient after CDT: the stent group (>2 mm Hg) and the control group (≤2 mm Hg). All patients were evaluated by color Doppler ultrasound at 1, 3, and 6 months after the operation to evaluate the patency of the iliofemoral vein. The Villalta score was used to evaluate the incidence of PTS. RESULTS: The primary and secondary patency rate of group 1 at 1, 3, and 6 months after operation were higher than that in group 2 (P < 0.05). In group 1, there was no significant difference in the primary and secondary patency rate between the stent group and the control group at 1, 3, and 6 months after the operation. The incidence of PTS in group 1 at 6 months after the operation was lower than that in group 2 (P < 0.05). In group 1, there was no significant difference in the incidence of PTS between the stent group and the control group at 6 months after the operation. CONCLUSIONS: Practice proves that it is simple and effective to guide stent implantation according to differences in pressure gradients. Two millimeter of mercury is the traditional standard for venous pressure interference in the pelvic area, and the effectiveness of this method was proved.

Preliminary report of a new type of braided vein stent in animals.

BACKGROUND: Iliofemoral vein stenosis or occlusion is a common cause of severe chronic venous insufficiency. Endovascular venous stenting has become a preferred treatment because it is minimally invasive and has a high safety profile. Despite the wide application of the wallstent, it is not specifically designed for veins. There are currently few studies on braided stents in the field of veins. We designed a novel braided vein stent, which has higher radial resistive force and more optimized looped ends structure compared with the wallstent. The purpose of this study was to evaluate the safety and performance of the stent in animals, providing a reference for further clinical trials. METHODS: The Wallstent is used as a control group. The novel stent and the Wallstent were implanted in the iliac vein of sheep. After 30 days and 90 days, vascular injury, thrombus, neointima coverage, and luminal stenosis were evaluated through venous angiography, endoscopic observation of stent specimen and histopathology. Imaging, histology, and integration data were analyzed by t-test for comparisons between the groups. RESULTS: Two groups of stents were successfully implanted. Follow-up observation showed that there was no thrombosis or obstruction >50% occurred in any group and no significant differences in patency, vascular injury, or intimal hyperplasia compared with the Wallstent. CONCLUSION: The novel stent significantly increases the radial resistive force and does not increase vascular injury, thrombus and stent stenosis during 30-day and 90-day follow-up. The next step is to further validate the effectiveness of the stent through long-term animal observation and human clinical trials.

Is May-Thurner Syndrome Combined with Left Iliac Arteriovenous Fistularare or Neglected?: Cases Report and Literature Review.

May-Thurner syndrome (MTS) is a condition in which the left common iliac vein is compressed by the right common iliac artery, which may cause swelling, pain or deep venous thrombosis of the left lower extremity.1 Postthrombotic syndrome, nonthrombotic chronic venous insufficiency, and recurrence after venous thrombosis are also possible complications. Although MTS combined with left iliac arteriovenous fistula is rarely reported, we treated 3 such cases in the past year.

Popliteal Vein Puncture Technique Based on Bony Landmark Positioning in Catheter-Directed Thrombolysis of Deep Venous Thrombosis: A Retrospective Review.

BACKGROUND: Catheter-directed thrombolysis (CDT) is an effective method for the treatment of deep venous thrombosis (DVT). The most widely used puncture technique involves the popliteal vein of the affected leg. We introduce a new puncture technique based on bony landmark positioning. METHODS: Between May 2012 and December 2014, we performed CDT in 96 cases of DVT using the puncture technique. The procedure is performed with the patient in the prone position on the angiography table. The popliteal vein is punctured according to tibial bony landmarks under fluoroscopic guidance. The needle puncture is made from the popliteal crease, along the direction of tibial lateral intercondylar eminence and parallel to the vertical axis. An introducer sheath is inserted after successful puncture followed by placement of a perfusion catheter of appropriate length in the thrombus. RESULTS: Technical success was achieved in 83 cases, with a success rate of 86.46% (83/96). The mean operation time was 38.6 ± 16.8 min, the mean fluoroscopy time was 11.3 ± 4.9 min, the mean effective dose (ED) was 77.2 ± 25.4 mGy, the mean dose-area product (DAP) was 3,927.5 ± 1,261 cGy cm(2). Compared with catheterization via incised ipsilateral small saphenous and contralateral femoral veins, the technique significantly shortened the operation and the X-ray exposure and reduced the dosage of ED and DAP. CONCLUSIONS: Popliteal vein puncture technique based on bony landmark positioning is a user-friendly alternative to CDT, especially in the absence of ultrasound localization.

Local and Remote Postconditioning Decrease Intestinal Injury in a Rabbit Ischemia/Reperfusion Model.

Intestinal ischemia/reperfusion (I/R) injury is a significant problem that is associated with high morbidity and mortality in critical settings. This injury may be ameliorated using postconditioning protocol. In our study, we created a rabbit intestinal I/R injury model to analyze the effects of local ischemia postconditioning (LIPo) and remote ischemia postconditioning (RIPo) on intestinal I/R injury. We concluded that LIPo affords protection in intestinal I/R injury in a comparable fashion with RIPo by decreasing oxidative stress, neutrophil activation, and apoptosis.

Fax Extension of the Right Renal Vein With a Remodeled Receptor Saphenous Vein in a Living-Donor Kidney Transplant: A Case Report.

The right kidney may be chosen for donor safety as the donor kidney in a living renal transplant. However, the short length of the right renal vein may increase technical difficulties and affect the implanted graft. We report a method that uses the remodeled receptor saphenous vein to reconstruct and extend the transplanted renal vein.

Endovascular repair of a transplant renal artery anastomotic pseudoaneurysm using the snorkel technique.

Renal artery pseudoaneurysms after renal transplantation are extremely uncommon and are able to cause severe complications such as aneurysm rupture or renal allograft loss. Treatment often leads to transplant nephrectomy. We successfully treated a transplant renal artery pseudoaneurysm with covered stents, which resulted in well-preserved renal function.