Stanisław Przywara

Bioengineered human acellular vessels for dialysis access in patients with end-stage renal disease: two phase 2 single-arm trials

BACKGROUND For patients with end-stage renal disease who are not candidates for fistula, dialysis access grafts are the best option for chronic haemodialysis. However, polytetrafluoroethylene arteriovenous grafts are prone to thrombosis, infection, and intimal hyperplasia at the venous anastomosis. We developed and tested a bioengineered human acellular vessel as a potential solution to these limitations in dialysis access. METHODS We did two single-arm phase 2 trials at six centres in the USA and Poland. We enrolled adults with end-stage renal disease. A novel bioengineered human acellular vessel was implanted into the arms of patients for haemodialysis access. Primary endpoints were safety (freedom from immune response or infection, aneurysm, or mechanical failure, and incidence of adverse events), and efficacy as assessed by primary, primary assisted, and secondary patencies at 6 months. All patients were followed up for at least 1 year, or had a censoring event. These trials are registered with ClinicalTrials.gov, NCT01744418 and NCT01840956. FINDINGS Human acellular vessels were implanted into 60 patients. Mean follow-up was 16 months (SD 7·6). One vessel became infected during 82 patient-years of follow-up. The vessels had no dilatation and rarely had post-cannulation bleeding. At 6 months, 63% (95% CI 47-72) of patients had primary patency, 73% (57-81) had primary assisted patency, and 97% (85-98) had secondary patency, with most loss of primary patency because of thrombosis. At 12 months, 28% (17-40) had primary patency, 38% (26-51) had primary assisted patency, and 89% (74-93) had secondary patency. INTERPRETATION Bioengineered human acellular vessels seem to provide safe and functional haemodialysis access, and warrant further study in randomised controlled trials. FUNDING Humacyte and US National Institutes of Health.

Carotid surgery affects plasma kynurenic acid concentration: a pilot study.

Background An increase in plasma kynurenic acid (KYNA) concentration has been observed following surgery, inflammation, and cerebral pathologies. The aim of the present study was to analyze the changes in plasma KYNA concentration in patients undergoing carotid surgery (CS). Material/Methods Adult patients undergoing elective carotid endarterectomy (CEA) or carotid angioplasty with stent placement (CAS) were studied. Plasma KYNA concentrations were analyzed before surgery and at 4 time points after CS. The amount of inflammation was measured as neutrophil-lymphocyte ratio (NLR). Results Forty patients (10 female and 30 male) aged 55–86 years of age were evaluated in this study. In patients with unstable carotid plaque, the plasma KYNA concentration was higher than in patients with stable carotid plaque. Moreover, the NLR was significantly higher in patients with unstable carotid plaque undergoing CEA than in patients undergoing CAS. Plasma KYNA concentration increased after surgery in patients undergoing CEA and CAS. There was a strong correlation between plasma KYNA concentration and NLR in patients with postoperative neurological disorders. Conclusions CS increases plasma KYNA concentration, and changes in plasma KYNA concentration can indicate neurologic outcomes in patients undergoing CS.

Axial splitting of the medial antebrachial cutaneous nerve facilitates second-stage elevation of basilic or brachial vein in patients with arteriovenous fistula

We describe a novel surgical technique to facilitate the second-stage elevation of the basilic or brachial vein in patients with first-stage brachial-basilic or autogenous brachial-brachial arteriovenous fistula by axial splitting of the medial antebrachial cutaneous nerve (MABCN). Filaments of the MABCN typically traverse the anterior aspect of the basilic and brachial veins. The second-stage elevation/shelf superficialization of the basilic or brachial vein, so as not to cause an injury to the MABCN, requires division of these veins with transposition over the nerve branches and subsequent reanastomosis. Our method of axial splitting of the MABCN enables elevation and shelf superficialization of the basilic or brachial vein without the division and reanastomosis of the vein. Twenty-eight patients underwent this simplified elevation. The nerve perineurium was incised longitudinally, nerve fibers were divided intrafascicularly, and cutaneous nerve branches were retracted aside. The vein was elevated between the divided nerves. On discharge and at 1-month follow-up, only one patient complained of localized patch hypoesthesia as reported in a simplified neurologic assessment questionnaire and neurologic examination.

The evaluation of the effectiveness of Tachosil in the treatment of lymphorrhea of the postoperative wound in the selected group of patients, after vascular reconstructive surgeries--preliminary report.

UNLABELLED Lymphorrhea of a postoperative wound after vascular reconstructive surgeries does not occur frequently but it accounts for a major complication. It should be brought to attention that during the intraoperative period it is impossible to diagnose any damages within the lymphatic system of the operated area. Additionally, the treatment of lymphorrhea with thermal abrasion does not usually bring the desired outcome. Therefore, the extended time of the postoperative wound treatment with the lymphatic drainage constitutes a standard method in such cases. The aim of the study was to evaluate the effectiveness of Tachosil surgical patch in the treatment of lymphorrhea of the postoperative wound in a selected group of patients who have undergone vascular reconstructive surgeries. Additionally, the aim of the study was to analyze the results and draw conclusions pertaining to the validity and effectiveness of the treatment with the use of Tachosil surgical patch. MATERIAL AND METHODS The observed group included 10 patients with lymphorrhea developed during the postoperative period. 6 of the observed patients have undergone the vascular reconstructive surgery with the implantation of the vascular prosthesis (distal femoropopliteal reconstruction bridge - 3 patients; iliofemoral reconstruction bridge - 1 patient; angioplasty of the common femoral artery (CFA) with the use of the prosthetic patch - 1 patient; the implantation of the bifurcated (type Y) aortofemoral prosthesis - 1 patient). The remaining patients in the observed group have undergone the restoration of patency of the CFA. Additionally, 1 patient has undergone the resection of the pseudo aneurysm in the distal part of the iliofemoral prosthesis. The vascular reconstructive surgery required the denudation and isolation of the common femoral artery from the surrounding tissue as a step 1. The persisting lymphorrhea of the postoperative wound, in the volume of more than 200 ml per day during the first 3 postoperative days, indicated the necessity for the inguinal wound revision. In addition, Tachosil surgical patch was applied at that time. The drain was placed over Tachosil patch. RESULTS Complete stop of lymphorrhea was shorter by 4.87 days in patients treated with the use of Tachosil in comparison to control group. These patients also had an average hospitalization time shorter by 3.88 days than patients in the control group. CONCLUSIONS Early intervention in the cases of lymphorrhea of the postoperative wound allows planning and conducting successful treatment. The use of Tachosil surgical patch in the treatment of lymphorrhea of the postoperative wound shortens the treatment and hospitalization periods. The use of Tachosil in the treatment of postoperative lymphorrhea appeared to be significantly more effective than the standard drainage method of treatment. Results obtained through this study pave the way for the research on other possible applications of Tachosil in the cases of lymphorrhea after vascular reconstructive surgeries.

Syndecan-4 Is an Independent Predictor of All-Cause as Well as Cardiovascular Mortality in Hemodialysis Patients

Background Left ventricular hypertrophy is associated withincreased mortality in hemodialysis (HD) patients.Syndecan-4 plays a role in many processes that are involved in the heart fibrosis and hypertrophy.We designed this study to prospectively determine whether syndecan-4 was predictive of mortality in a group of HD patients. Methods In total, 191 HD patients were included. Clinical, biochemical and echocardiographic parameters were recorded. HD patients were followed-up for 23.18 ± 4.02 months. Results Syndecan-4 levels correlated strongly with geometrical echocardiographic parameters and ejection fraction. Relations with pressure-related parameters were weak and only marginally significant. Using the receiver operating characteristics the optimal cut-off points in predicting all-cause as well as cardiovascular (CV) mortality were evaluated and patients were divided into low and high syndecan-4 groups. A Kaplan–Meier analysis showed that the cumulative incidences of all-cause as well as CV mortality were higher in high serum syndecan-4 group compared with those with low serum syndecan-4 (p<0.001 in both cases).A multivariate Cox proportional hazards regression analysis revealed syndecan-4 concentration to be an independent and significant predictor of all-cause (hazard ratio, 2.99; confidence interval, 2.34 to 3.113; p<0.001)as well as CV mortality (hazard ratio, 2.81;confidence interval, 2.28to3.02; p<0.001). Conclusions Serum syndecan-4 concentration reflects predominantly geometrical echocardiographic parameters. In HD patients serum syndecan-4 concentration is independently associated with all-cause as well as CV mortality.

Serumska razina za neuron specifične enolaze kao biljeg ishemijsko-reperfuzijskog oštećenja u bolesnika podvrgnutih karotidnoj endarterektomiji

In patients with atherosclerotic stenosis of the extracranial segment of internal carotid artery, surgical intervention is an effective method to prevent cerebral ischemic stroke. However, this surgical procedure may cause vascular brain damage. The aim of the study was to investigate consequential brain ischemia-reperfusion injury by measuring the cerebral specific marker, neuron-specific (NSE), in serum of patients having undergone internal carotid endarterectomy (CEA). The study involved 25 patients that underwent CEA due to internal carotid artery stenosis. Blood samples were obtained from each patient on three occasions: within 24 h prior to surgery, 12 h after surgery, and 48 h after surgery. Serum NSE levels were measured by a commercially available enzyme-linked immunosorbent assay. The study showed that serum NSE level was statistically significantly increased 48 h after CEA as compared with the level 12 h after surgery and the level before surgery (p<0.05). Difference in serum NSE between the level before surgery and 12 h after CEA was not statistically significant (p>0.05). Data from our study showed CEA to affect serum NSE in patients with significant internal carotid artery stenosis. Thus, serum NSE may be used as a biochemical marker of brain ischemia-reperfusion injury following CEA.

Effect of carotid endarterectomy on brain damage markers

Carotid endarterectomy (CEA) is a recommended treatment in the prevention of ischemic stroke. However, this procedure may cause neurological complications caused by cerebrovascular damage. While YKL‐40 is a proinflammatory protein, neurofilament light polypeptide (NEFL) and brain lipid‐binding protein (FABP7) are structural components of the brain. The aim of the study was to investigate YKL‐40, NEFL, and FABP7 in the serum of patients undergoing CEA.

Application of endovenous mechanochemical ablation (MOCA) with Flebogrif™ to treat varicose veins of the lower extremities: a single center experience over 3 months of observation

Introduction. Chronic venous insufficiency is one of the most common medical conditions among highly developed societies. The majority of patients (70%) suffer from saphenous veins incompetency. The study presents results of a 3-month follow-up of application of venous mechanochemical ablation system with the Flebogrif catheter. Material and methods. The study was conducted on 200 patients, including 170 women and 30 men treated with ablation with Flebogrif to treat varicose veins. All patients were qualified based on the ultrasound in a standing position confirming incompetence of the great saphenous vein or small saphenous vein. The vein was punctured under ultrasound guidance in the distal part of the incompetent segment. The area of vascular access was anesthetized with 0.5 mL of 1% lignocaine. The compression therapy in the form of the first grade medical elastic stocking was used after the surgery. Results. The initial technical success of the surgery was achieved in all the patients. During the 3-month follow-up, recanalization occurred in 8 cases, in 5 patients great saphenous vein and in 3 small saphenous vein recanalised. Based on the recommendations of the European Consensus Meeting on Foam Sclerotherapy, 7 cases were defined as complete recanalization and 1 as partial. The analysis of numerical data obtained with Venous Clinical Severity Score and Clinics Ethiology Anatomy Pathophysiology Classification showed a statistically significant decrease in the severity of clinical symptoms compared to ones before the surgery and between particular days of the observation during the 3-month follow-up. Conclusions. The procedure is highly effective reaching 96% at 3 months of follow-up, provides good cosmetic effect and the low rate of complications. Minimal invasiveness of mechanochemical ablation with FlebogrifTM may improve the quality of life during the postoperative period. A long-term observation is recommended to achieve a full-value assessment of this novel method.

Endovenous laser ablation is an effective treatment for great saphenous vein incompetence in teenagers.

Objectives The current knowledge of chronic venous disease in teenagers and its treatment is very limited. The aim of the study is to present our experience and the available literature data on the treatment of varicose veins in teenagers with endovenous laser ablation of the great saphenous vein. Methods Five patients, aged 15–17 years, were qualified for surgery, based on typical signs and symptoms of chronic venous disease. Minimally invasive treatment with endovenous laser ablation of the great saphenous vein was applied. Results The technical success of surgery was achieved in all patients. Over a 2-year follow-up we did not observe any case of recanalisation of the great saphenous vein, recurrence of varicose veins, or serious complications, such as deep vein thrombosis or pulmonary embolism. One patient presented with resolving of post-operative bruising, and two cases of local numbness were transient. Conclusions Endovenous laser ablation of the great saphenous vein in the treatment of chronic venous disease in teenagers is effective and safe. The method provides excellent cosmetic effects, very short recovery time and high levels of patient satisfaction.

Serum glial fibrillary acidic protein as a marker of brain damage in patients after carotid endarterectomy

Introduction. Surgical treatment of the extracranial section of internal carotid artery stenosis is an effective method of preventing cerebral ischaemic stroke. However, this surgical procedure may cause vascular brain damage. The aim of the study was to measure glial fibrillary acidic protein (GFAP) as a marker of brain damage in the serum of patients that underwent internal carotid endarterectomy (CEA). Material and methods. This study involved 25 participants who underwent CEA because of internal carotid artery stenosis. Blood samples were taken from each patient at three different times; within 24 hours prior to surgery, 12 hours after the surgery, and 48 hours after the surgery. Serum GFAP levels were measured by a commercially available enzyme-linked immunosorbent assay (ELISA). Results. The study showed that serum GFAP levels were not statistically different between all the three measurements (p > 0.05). There was also no statistical significant difference in serum GFAP levels between symptomatic and asymptomatic patients (p > 0.05). There was no statistically significant correlation in serum GFAP level 12 and 48 hours after the surgery with the clamping time (p > 0.05). There was also no significant correlation in the serum GFAP levels with the velocity of blood flow in the internal carotid artery before CEA and after surgery (p > 0.05). Conclusions. The study revealed that CEA does not change serum GFAP levels. Thus, GFAP cannot be a biochemical marker of brain damage after this surgery.