Fabrication and characterization of a novel compliant small-diameter PET/PU/PCL triad-hybrid vascular graft.

Nanomaterial structures are highly contributive in tissue engineering vascular scaffolds (TEVS) due to their ability to mimic the nanoscale dimension of the natural extracellular matrix (ECM) and the existing mechanical match between the native blood vessel and the scaffold as a vascular graft. The aim of this study was to develop and mechanically improve the nanofibrous triad-hybrid scaffolds with different composite ratios of polyethylene terephthalate (PET), polyurethane (PU), and polycaprolactone (PCL). The morphological, biological, mechanical, and biomechanical properties of the neat and hybrid structures were examined using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), tensile strength, compliance, burst pressure, MTT assay, and by implanting the specimens under rat skin to explore the immune system in vivo. The results showed that the fiber diameter and porosity changes in the triad-hybrid electrospun scaffold ranged within 388 ± 88 to 547 ± 89 nm and 56.60 ± 2.06% to 75.00 ± 1.94%, respectively. In addition, the changes in the tensile strength and force in the scaffolds were within the ranges 2.7 ± 0.44 to 5.27 ± 0.83 MPa and 2.68 ± 0.19 to 10.03 ± 0.75 MPa, respectively. Also, the compliance and burst pressure of the structures were reported as 4.05 ± 0.21 to 7.09 ± 0.49 and 1623 ± 329 to 2560 ± 121 mmHg, respectively. According to the MTT assay, high cell viability was observed on the triad-hybrid structures with a high percentage of PET when compared to that of PU. The findings of this research demonstrate that the PET/PU/PCL triad-hybrid vascular scaffold has enough potential to be used in vascular tissue engineering application.

Efficacy of Using Non-tunneled Dialysis Catheters During Arteriovenous Fistula till its Maturation: A Retrospective Study.

PURPOSE: Due to high prevalence of diabetes mellitus and subsequent nephropathy, the need for access to start and continue dialysis has been increased. In this study, we aim to study the efficacy and complications of non-tunneled catheters (NTC) till fistula maturation because of being easy and cheap implementation as well as similar complications compared to tunneled catheters (TC). MATERIALS AND METHODS: In this retrospective observational study, 247 patients with first-time AVF creation referred to Vascular Surgery Centre of Mashhad University of Medical Sciences, Iran, were recruited since March 2016 to December 2017. Only 153 patients who have completed the study, and were monitored every two weeks in case of un-maturation along with the status of temporary catheters. RESULTS: Mean age of patients was 49.9 ± 7.74 years, and 75 (49%) were females, which was comparable with literature. Preference of NTC implementation was at right jugular because of the easy access to central vein and less chance of complications. Catheter location was at right internal jugular in 61.4% of the patients. Out of 24 femoral cases, 18 was done at femoral. AVF location was done at left/right cubital in most cases (52.3%). The rate of infection was 15.0%, which was less than NTC's infections reported in the literature. CONCLUSION: Use of non-tunneled catheter in the form of outpatient in the period of AVF maturation time is recommendeddue to similar complication rate.

Small-diameter vascular graft using co-electrospun composite PCL/PU nanofibers.

Small-diameter vascular scaffolds have been developed by a co-electrospinning method using polyethylene terephthalate (PCL) and elastic polytetrafluoroethylene (PU) as biopolymers with long degradation time. Although they possess favorable properties, individually these two polymers do not meet the requirements for the production of synthetic vascular scaffolds. The co-electrospinning method was adopted to develop and mechanically improve the composite PCL/PU vascular scaffolds. The morphological, mechanical and biological properties of these vascular scaffolds were evaluated through scanning electron microscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy, compliance, tensile testing and MTT assay. The in vivo study of the vascular scaffolds was performed by implanting them on rat and sheep models. The compliance of the composite vascular scaffolds improved by up to 43% through an increased percentage of PU from 10%-90%. The obtained UTS of the scaffolds at 10%, 25%, 50%, 75% and 90% of PU were 4.7 ± 0.34, 3.4 ± 0.6, 4.8 ± 0.62, 2.2 ± 0.34 and 4.4 ± 1.9 MPa, respectively. The results of MTT assays indicated that the cell growth on the scaffolds was augmented when compared to the control, from day one to day seven. Mild edema, mild foreign-body granulomatous reaction and mild fibrosis were observed by pathology test as the side effects in the composite scaffold with 50% PCL. Doppler ultrasound and angiography images confirm that no aneurysm, thrombogenesis, neointimal hyperplasia or occlusion exist, and there is complete patency at the end of an eight month investigation. The fabricated composite vascular scaffolds provide appropriate mechanical and biological properties and clinical requirements, indicating their required potential to be applied as a small-diameter vascular graft.

A successful experience in managing a chylous reflux: importance of lymphoscintigraphy.

Chylous reflux is described as the backflow of chyle through the varicose lymphatics with incompetent lymph valves and leakage of the lymph. The valves in the dilated, varicose, tortuous lymph vessels become incompetent, and as a result, the lymph blended with chyle, reflux into the lower limbs or the genitalia. Reflux causes delayed lymphatic transport in the affected lower extremity and chronic lymphedema can develop. Vesicles containing chyle could appear on the skin of the involved parts, and milky fluid discharge of the lymph and chyle interferes greatly with quality of life.

Management of sigmoid volvulus: options and prognosis.

OBJECTIVE: To describe the management of sigmoid volvulus with reference to the type of surgical procedures performed and to determine the prognosis of sigmoid volvulus. STUDY DESIGN: A case series. PLACE AND DURATION OF STUDY: Ghaem Hospital of Mashhad, University of Medical Sciences, Mashhad, Iran, from 1996 to 2008. METHODOLOGY: A total of 944 cases of colon obstruction were reviewed. Demographic, laboratory and treatment results, mortality and complications were recorded. The data was analyzed using descriptive statistics as frequency and percentage for the qualitative variables and mean and standard deviation values for the quantitative variables. Also chisquare and Fisher's exact test were used for the association between the qualitative variables. SPSS statistical software (version 18) was used for the data analysis. RESULTS: In all patients except those with symptoms or signs of gangrenous bowel, a long rectal tube was inserted via the rectosigmoidoscope which was successful in 80 (36.87%) cases. Rectosigmoidoscopic detorsion was unsuccessful in 137 (63.13%) patients, who underwent an emergent laparotomy. The surgical procedures performed in these cases were resection and primary anastomosis in 40 (29.1%), Mikulicz procedure in 9 (6.6%), laparotomy detorsion in 37 (27.01%), Hartmann procedure in 47 (34.3%), mesosigmoidoplasty in 3 (2.19%) patients and total colectomy in one (0.73%) case. The overall mortality was 9.8% (22) patients. CONCLUSION: In sigmoid volvulus, the most important determinant of patient outcome is bowel viability. The initial treatment of sigmoid colon volvulus is sigmoidoscopy with rectal tube placement.

Prehospital management of gunshot patients at major trauma care centers: exploring the gaps in patient care.

BACKGROUND: Prehospital management of gunshot-wounded (GW) patients influences injury-induced morbidity and mortality. OBJECTIVES: To evaluate prehospital management to GW patients emphasizing the protocol of patient transfer to appropriate centers. PATIENTS AND METHODS: This prospective study, included all GW patients referred to four major, level-I hospitals in Mashhad, Iran. We evaluated demographic data, triage, transport vehicles of patients, hospitalization time and the outcome. RESULTS: There were 66 GW patients. The most affected body parts were extremities (60.6%, n = 40); 59% of cases (n = 39) were transferred to the hospitals with vehicles other than an ambulance. Furthermore, 77.3% of patients came to the hospitals directly from the site of event, and 22.7% of patients were referred from other medical centers. EMS action intervals from dispatchers to scene departure was not significantly different from established standards; however, arrival to hospital took longer than optimal standards. Additionally, time spent at emergency wards to stabilize vital signs was significantly less in patients who were transported by EMS ambulances (P = 0.01), but not with private ambulances (P = 0.47). However, ambulance pre-hospital care was not associated with a shorter hospital stay. Injury Severity was the only determinant of hospital stay duration (ß = 0.36, P = 0.01) in multivariate analysis. CONCLUSIONS: GW was more frequent in extremities and the most patients were directly transferred from the accident site. EMS (but not private) ambulance transport improved patients' emergency care and standard time intervals were achieved by EMS; however more than a half of the cases were transferred by vehicles other than an ambulance. Nevertheless, ambulance transportation (either by EMS or by private ambulance) was not associated with a shorter hospital stay. This showed that upgrade of ambulance equipment and training of private ambulance personnel may be needed.

Temporary worsening of kidney function following aortic reconstructive surgery.

INTRODUCTION: Little is known about the incidence of temporary kidney dysfunction following major vascular surgeries. We aimed to assess the frequency of temporary decreased kidney function following aortic surgeries. MATERIALS AND METHODS: In a retrospective study, we assessed 108 hospital records of the patients who had undergone elective open abdominal surgery of aortic aneurysm. Preoperative and postoperative (days 1, 2, and 3) data on estimated glomerular filtration rate (GFR) were collected and evaluated in relation to the patients' clinical characteristics and outcomes. A decline greater than 10% in GFR on day 1 or 2, and then, an increase of GFR to a level of maximum 10% below the baseline value on the third postoperative day was considered as temporary worsening of kidney function. Postoperative alterations of GFR not greater than 10% in relation to the baseline were considered as improved or unchanged kidney function. Two patients with persistent decrease in GFR were excluded. RESULTS: Temporary worsening of kidney function was seen in 25 patients (23.6%). Short-term mortality rate was 44.0% in this group of patients, while it was 17.3% in those without decreased GFR (P = .006). According to the regression analysis, the only predictor of mortality was temporary worsening of kidney function, with a hazard ratio of 4.03 (95% confidence interval, 1.44 to 11.31; P = .008). CONCLUSIONS: Nearly 1 out of 4 aortic surgeries results in kidney dysfunction. Albeit temporary in most cases, it seems to be associated with a higher short-term mortality rate.