Efficacy of Balloon Angioplasty in Patients with Central Venous Stenosis or Obstruction Resulting from Central Vein Catheter Placement.

Background: Prolonged catheter insertion in central veins of hemodialysis patients usually causes central venous stenosis (CVS). These patients present with upper limbs, head and neck, and chest edema or hemodialysis problems. This study was done to determine the clinical success of balloon angioplasty for the treatment of symptomatic CVS/obstruction. Materials and Methods: Sixty-one hemodialysis patients who underwent endovascular treatment for CVS enrolled in this cross-sectional study between January 2017 and July 2018 at our institute. Enrollment included 29 female and 32 male subjects with a mean age of 58.9 ± 9.9 (range: 33-78) years. Results: A total of 61 patients underwent interventions for endovascular treatment of central venous disease. 38 out of 61 patients completed all three phases of the study (the beginning, after 3 and 6 months). The average diameter of central vein in venography at the beginning of the study, 3 and 6 months later were 8.66 mm, 8.03 mm, and 7.66 mm, respectively. The average patency was 45%, and 54% and 51% at the beginning of the study, 3 and 6 months after the treatment, respectively. There was an increase in central vein patency after 3 months of treatment, with significant difference among 3 phases (P < 0.000). Conclusion: Endovascular treatment is effective and safe for patients with central vascular stenosis with less complication rate compared to open surgical treatments, and the rate of venous patency in the treated veins with balloon angioplasty after 3 months is excellent, but this rate after 6 months is significantly reduced.

Preclinical in vivo assessment of a cell-free multi-layered scaffold prepared by 3D printing and electrospinning for small-diameter blood vessel tissue engineering in a canine model.

Tissue-engineered vascular grafts (TEVGs) are promising alternatives to existing prosthetic grafts. The objective of this study is to evaluate the clinical feasibility of a novel multi-layered small-diameter vascular graft that has a hierarchical structure. Vascular grafts with elaborately designed composition and architecture were prepared by 3D printing and electrospinning and were implanted into the femoral artery of 5 dogs. The patency of the grafts was assessed using Doppler ultrasonography. After 6 months, the grafts were retrieved and histological and SEM examinations were conducted. During implantation, the grafts exhibited resistance to kinking and no blood seepage thanks to the helical structure of the innermost and outermost layers. The grafts showed a high patency rate and remodelling ability. At 6 months post-implantation, the lumen was endothelialized and middle layers were regenerated by infiltration of smooth muscle cells (SMCs) and deposition of extracellular matrix (ECM). These results suggest that the multi-layered vascular graft may be a promising candidate for small-diameter blood vessel tissue engineering in clinical practice.

Incidence of steal syndrome following arteriovenous fistula and arteriovenous graft.

BACKGROUND: Renal failure is one of the dangerous chronic diseases that different solutions are used for dialysis in these patients. Arteriovenous graft (AVG) and arteriovenous fistula (AVF) are two communication methods for dialysis in these patients, associated with pain, sensory and Pulse disturbances, and even limb necrosis. Using cubital AVF and AVG for hemodialysis is a critical issue in vascular surgery. Arterial steal syndrome is an essential medical condition requiring surgical interventions. In this research project, we decided to measure the incidence of steal syndrome among AVF and AVG patients and compare them with each other. METHODS: This cohort study was performed in Al-Zahra Hospital, Isfahan, Iran, from 2018 to 2020. Two hundred one patients undergoing AVF or AVG were included, and patients were followed for six months. The frequency of pain symptoms, anesthesia and pulse disorders, necrosis of the limbs, and the frequency of steal syndrome were assessed. RESULTS: Among the studied patients, 2 cases in the AVF group and 10 cases in the AVG group had steal syndrome, and there was a significant difference between the two groups based on the frequency of steal syndrome (P=0.007). Also, there was a considerable difference between the two groups based on the pulse disorder (P<0.05), but there was no significant difference between the two groups in terms of symptoms of sensory impairment, pain, and evidence of necrosis (P>0.05). CONCLUSION: AVF technique is better than AVG in creating symptoms of steal syndrome, and also, the number of symptoms such as pulse disorder was relatively less seen in the AVF method.

A Randomized Clinical Trial of Low-dose Warfarin Therapy for Improving the Longevity of Permanent Arteriovenous Catheters.

BACKGROUND: The patency of a permanent arteriovenous catheter plays a significant role in the functioning of the catheter among patients dependent on the hemodialysis. Thrombosis formation is one of the most critical reasons for the short-term efficacy of the embedded catheters. The present study aimed to evaluate the efficacy and safety of warfarin for hemodialysis catheter failure prevention. METHODS: This randomized clinical trial has been conducted on patients under hemodialysis using a permanent arteriovenous catheter. The patients were randomly allocated to the control group and the intervention group. The intervention group was treated with warfarin to achieve a target international normalized ratio (INR) of 1.5-2. The control group did not receive any treatment. The patients were followed for 12 months to assess the efficacy defined as the incidence of catheter clotting and safety defined as warfarin-related hemorrhage. RESULTS: Eighty-six patients with end-stage renal disease under hemodialysis were included, among which 43 ones were allocated to the intervention group and the latter ones to the control group. The participants of both groups were similar in terms of demographic, clinical, and baseline laboratory characteristics. Four patients (9.3%) presented with warfarin-induced hematoma, among which the warfarin administration stopped for 5.33 ± 1.44 days and then restarted again. None of the patients was forced to cease warfarin therapy because of significant hemorrhages. The mean duration of catheter functioning was 8.30 ± 1.75 months in the intervention group versus 3.90 ± 1.12 months in the controls (P-value<0.001). CONCLUSIONS: Based on the findings of the present study, the use of warfarin to achieve an INR level of 1.5-2 could effectively lead to a longer duration of permanent hemodialysis catheter functioning.

Effects of Intravenous and Catheter Directed Thrombolytic Therapy with Recombinant Tissue Plasminogen Activator (Alteplase) in Non-Traumatic Acute Limb Ischemia; A Randomized Double-Blind Clinical Trial.

OBJECTIVE: To evaluate the efficacy and safety of intravenous and catheter directed thrombolysis by recombinant tissue plasminogen activator (Alteplase) in the patients with non-traumatic acute limb ischemia (ALI). METHODS: This was a randomized clinical trial being performed between 2009 and 2011 in Mashhad University of Medical Sciences. We included those patients who were<75 years, with symptoms of less than 14 days duration, ALI of grade IIa and IIb (according to Rutherford classification) and absence of distal run off. Baseline assessment of peripheral circulation performed in all the patients. Patients were randomly assigned to undergo intravenous (n=18) or catheter directed thrombolysis (n=20) with Alteplase. The primary endpoint of the study was improvement of clinical status measured by Rutherford classification, ankle brachial index (ABI), visual analogue scale (VAS) score measured at 1, 3 and 6 months. The secondary endpoint of the study was complete or near complete recanalization of the occluded artery. RESULTS: A total number of 38 patients with mean age of 54.13±13.5 years were included in the study. There were 23 (60.5%) men and 15 (39.5%) women among the patients. Overall 3 (7.9%) patients had upper and 35 (92.1%) lower extremity ischemia. There was no significant difference between two study groups. None of the patients experienced major therapeutic side effects. Both ABI and VAS score improved in patients who have received first dose of t-PA within 24-hourof ALI. There was no significant difference between two study groups regarding the 6-month clinical grade (p=0.088), VAS score (p=0.316) and ABI (p=0.360). The angiographic improvement was significantly higher in CDT group (p<0.001). CONCLUSION: Intravenous and catheter directed thrombolysis with t-PA is a safe and effective method in treatment of acute arteriolar ischemia of extremities. However there both intravenous thrombolysis and CDT are comparable regarding the clinical outcome.