Rebuilding vascular access: from the viewpoint of mechanics and materials.

This review presents a comprehensive analysis of vascular access in hemodialysis, focusing on the current modalities, their associated challenges, and recent technological advancements. It closely examines the status of three primary types of vascular access: arteriovenous fistulas, arteriovenous grafts, and central venous catheters. The review delves into the complications and pathologies associated with these access types, emphasizing the mechanobiology-related pathogenesis of arteriovenous access. Furthermore, it explores recent clinical trials, biomaterials, and device innovations, highlighting novel pharmaceutical approaches, advanced materials, device designs, and cutting-edge technologies aimed at enhancing the efficacy, safety, and longevity of vascular access in hemodialysis. This synthesis of current knowledge and emerging trends underscores the dynamic evolution of vascular access strategies and their critical role in improving patient care in hemodialysis.

Establishing an autogenous vascular access program in a Guatemalan comprehensive pediatric nephrology center.

BACKGROUND: The Guatemalan Foundation for Children with Kidney Diseases collaborated with Bridge of Life, a not-for-profit charitable organization, to establish a vascular access program. We reviewed our experience with graded surgical responsibility and structured didactic training, creating arteriovenous fistulas (AVF) for Guatemalan children. METHODS: Pediatric vascular access missions were completed from 2015 to 2023 and analyzed retrospectively. Follow-up was completed by the Guatemalan pediatric surgeons, nephrologists, and nursing staff. AVF patency and patient survival were evaluated by Kaplan-Meier life-table analysis with univariate and multivariable association between patient demographic variables by Cox proportional hazards models. RESULTS: Among a total of 153 vascular access operations, there were 139 new patient procedures, forming the study group for this review. The mean age was 13.6 years, 42.6% were female, and the mean BMI was 17.3. Radial or ulnar artery-based direct AVFs were established in 100 patients (71.9%) and ten of the 25 transposition procedures. Brachial artery inflow was required in 29 direct AVFs (20.9%). Two patients underwent femoral vein transpositions. Access-related distal ischemia was not encountered. Seven of the AVF patients later required access banding for arm edema; all had previous dialysis catheters (mean = 9, range 4-12). Primary and cumulative patency rates were 84% and 86% at 12 months and 64% and 81% at 24 months, respectively. The median follow-up was 12 months. Overall patient survival was 84% and 67% at 12 and 24 months, respectively. There were no deaths related to AVF access. CONCLUSIONS: Safe and functional AVFs were established in a teaching environment within a Guatemalan comprehensive pediatric nephrology center.

[Stenotic FAV: Success of the Collaboration Between Spoke and HUB].

The arteriovenous fistula constitutes the vascular access of first choice in hemodialysis. We present three clinical cases that highlight the resolution in interventional radiology of venous stenosis, one of the major complications. Clinical monitoring and instrumental diagnostics with color Doppler ultrasound have prevented the failure of the AVF due to high risk of thrombosis. The angiographic interventions, thanks to the collaboration between Spoke and Hub, were completed without complications.

[Clinical Thermography for the Management of Hemodialysis Vascular Access].

The arteriovenous fistula (AVF) represents the favorite vascular access in individuals with chronic kidney disease (CKD). Because AVF is a guarantee of survival for these patients, proper surgical packing and a timely follow-up program is crucial. Although a good objective examination of the limb site of FAV provides useful information both in planning the fistula surgery and in its surveillance and monitoring, it is now well established that the advent of instrumental diagnostics (ultrasonography, digital angiography, Angio-TC, MRI) has contributed significantly to improving primary and secondary patency of FAV and early diagnosis of vascular access complications. In this area, clinical thermography, a noninvasive and nondestructive diagnostic technique for assessing minute surface temperature differences, has shown good potential for the assessment of AVF. In fact, thermographic analysis of a limb site of AVF shows an increase in temperature at the site of the anastomosis and along the course of the arterialized vein. In this article we report our experience on the use of thermography in preoperative evaluation and postoperative surgical packing of an AVF. Further studies could validate the use of clinical thermography as a diagnostic technique to be used in the field of hemodialysis vascular accesses.

A review of the current recommendations and practices for hemodialysis access monitoring and maintenance procedures.

The growing number of prevalent arteriovenous (AV) accesses has been associated with an increase in the incidence of procedures being performed to maintain patency. To reduce the rate of unnecessary procedures, the 2019 Kidney Disease Outcome Quality Initiative guidelines addended the AV access surveillance recommendations, which includes clinical monitoring and assessment of dialysis adequacy alone. Abnormal clinical findings would necessitate follow-up angiography with or without confirmatory duplex ultrasound. Due to poor patency, increased surveillance schedules have been proposed to identify stenosis early and potentially prevent acute thrombotic events and AV access failure. In this review, we outlined current AV access monitoring and maintenance procedure recommendations, as described by the Centers for Medicare and Medicaid Services and 2019 Kidney Disease Outcome Quality Initiative guidelines. In addition, we highlight the findings of recently published randomized controlled trials that have examined increased surveillance schedules.

Stereotactic radiosurgery for intracranial dural arteriovenous fistulas: patient outcomes and lessons learned over a 3-decade single-center experience.

OBJECTIVE: The role of stereotactic radiosurgery (SRS) in the management of intracranial dural arteriovenous fistula (dAVF) is unclear given the rarity of this lesion and the variability in treatment paradigms. This study describes a 3-decade experience with the SRS technique and its outcomes for patients with dAVF. METHODS: The authors conducted a retrospective analysis of patients with dAVF who had undergone single-fraction SRS in the period from 1990 to 2021. The imaging modality initially used for targeting was angiography alone, then angiography plus MRI, and most recently MRI alone. RESULTS: Two hundred twenty-two patients underwent SRS alone (n = 56, 25%) or SRS plus embolization (n = 166, 75%), depending on the severity of symptoms or the presence of cortical venous drainage (CVD). Most patients were women (64%), and the median patient age was 60 years. Common presenting symptoms were pulsatile bruit (55%), visual change or chemosis (21%), headache (10%), and intracerebral hemorrhage (5%). The most frequent dAVF location was the transverse or sigmoid sinus (44%), followed by the cavernous sinus (24%), jugular bulb (9%), and torcula (5%). CVD was noted in 28% of cases, and venous ectasia in 5%. Borden dAVF types among the patients were I (72%), II (20%), and III (8%). Cognard dAVF types among the patients were I (44%), IIa (27%), IIb (5%), IIa+b (15%), III (4%), and IV (5%). The median SRS treatment volume was 7.6 cm3; the median margin and maximum doses were 18 and 36 Gy, respectively. Follow-up after SRS was available for 209 patients (median follow-up 31 months). Obliteration was noted in 75% of the patients (110/147) with follow-up vascular imaging; the median time to obliteration was 37 months. Multivariate analysis revealed that a cavernous sinus dAVF location was predictive of radiological obliteration (HR 1.86, 95% CI 1.08-3.18, p = 0.024). The absence of CVD was predictive of obliteration in subgroup analysis of non-cavernous sinus dAVF (HR 0.53, 95% CI 0.29-0.98, p = 0.04). Symptoms resolved in 86% of patients (160/185) with clinical follow-up. Twelve patients (5.4%) had complications related to angiography for SRS planning (n = 2, 0.9%), embolization (n = 3, 1.4%), post-SRS hemorrhage (n = 1, 0.5%), delayed sinus thrombosis (n = 1, 0.5%), radiation-induced tumors (n = 2, 0.9%), and chronic encapsulated expanding hematoma (n = 3, 1.4%). CONCLUSIONS: SRS alone or in conjunction with embolization provided obliteration and symptom relief for the majority of patients with dAVF, with a low rate of procedure-related morbidity. Patients are at risk for late radiation-related complications, which can require treatment many years after SRS.

Management of Arteriovenous Fistula After Successful Kidney Transplantation in Long-Term Follow-Up.

Arteriovenous fistula (AVF) is the best method of vascular access for hemodialysis. This approach can lead to several complications, such as hyperkinetic heart failure due to a hyperfunctional AVF or dilatation of the feeding artery. These are late complications, especially in patients after a successful kidney transplantation. An observational study was performed focusing on patients more than 12 months after kidney transplantation. The AVF was evaluated by ultrasound and, if the outflow exceeded 1.5 L/min, an echocardiogram was performed. Surgical management was indicated if the cardiac index was higher than 3.9 L/min/m2 or upon finding a brachial artery aneurysm. A total of 208 post- kidney transplantation patients were examined over a 3-year period, of which 46 subjects (22.11%) had hyperfunctional AVF and 34 cases (16.34%) of feeding artery dilatation were determined. In total, 40 AVF flow reduction and 6 AVF ligation procedures were performed. The median AVF flow before and after the reduction was 2955 mL/min and 1060 mL/min, respectively. Primary patency after flow reduction was 88.3% at 12 months. Late AVF complications in patients following kidney transplantation are quite common. It is necessary to create a screening program to monitor AVFs in these patients.

A case of dural arteriovenous fistula at the craniocervical junction successfully treated by transvenous embolization.

Arteriovenous fistula (AVF) occurring within the craniocervical junction (CCJ) is an uncommon vascular anomaly. A 56-year-old man presented with cervical pain and gait disturbances. Computed tomography revealed a hematoma in the epidural space at the cervical spinal level. Subsequent cerebral angiography revealed an epidural shunt at the CCJ, leading to a diagnosis of epidural AVF (EDAVF). Transvenous embolization, performed under general anesthesia, successfully resolved the shunt. Transarterial embolization of CCJ-EDAVFs carries a substantial risk of ischemic complications. Conversely, transvenous embolization poses a lower risk of ischemic complications and has potential as a beneficial treatment option for CCJ-EDAVFs. Herein, we present a unique case of CCJ-EDAVF that was successfully treated with transvenous embolization.

Outcomes of AV fistula formation for dialysis patients using interrupted sutures one-year single center study.

Objectives: To document the Outcomes of AV fistula formation for dialysis patients using interrupted sutures. Methods: In this Cross-sectional study conducted at PNS Shifa Karachi, from June 2022 to June 2023, patients above 18 years of age, male or female, with ESRD/CKD were included. After clinical screening and ultrasound doppler, the distal most part of wrist was considered as a site for radio cephalic AVF. Operation was performed under surgical loupe with 4.5x magnification. Standard incision of about 4-5 cm oblique proximal to the wrist crease was given at the volar surface on the radial side of Distal forearm, extending till the lateral side up to the snuffbox. Subcutaneous tissue was incised and dissection was done to identify the cephalic vein and radial artery. Distal most end of the cephalic vein was ligated using vicryl 4-0 suture and cephalic vein dissected free from the underling tissue to mobilize it up to the radial artery. Results: During the study N=35 patients who required AVF creation visited the department. The mean age of the study participants was 59.34±15.48. If thrill at the site of AVF and backflow at cut end of cephalic vein were present the surgeons were satisfied, higher satisfaction among the surgeon was achieved in the AVF created at brachiocephalic artery while the diameter of vessels didn't contribute in surgeon satisfaction. Conclusion: Presence of thrill at the site of AVF and backflow at cut end of cephalic vein have strong association with good prognosis of AVF.

To evaluate the complication and patency rate of superficial femoral vein transposition in tertiary care center.

INTRODUCTION: When all access options in the upper extremity have been exhausted, an autologous access can be created in lower extremity. The purpose of this study is to report our experience with superficial femoral vein transposition (SFVT) results in terms of postoperative complication and patency rate. MATERIALS AND METHODS: In the time period from January 1, 2019 to April 30, 2021, thirty-five cases of SFVT performed at our large tertiary care center Sindh Institute of Urology and Transplantation (SIUT). All patients had exhausted upper arm veins or had central vein obstructions. Medical records of all patients were traced, patients were interviewed using a standard proforma and evaluated the current AVF function in the OPD clinic or by telephone calls. Data including demographics and postoperative complications were collected. RESULTS: Thirty-nine cases of SFVT performed at our institute. Three were immediately lost to follow up so they were excluded from the study. Mean patient age was 30 ± 13.4 years. Most of our patients were females (57%) and 15 males (43%) with an average age of 29.05 years. The most common underlying renal diseasewas unknown in 16 (45%).Thirty-five patients included in the analysis; out of which primary failure observed in 4 patients, three patients were expired before fistula maturation and 3 were expired before 6 months. The remaining 25 fistulas patency rates were estimated. No any patient died due to fistulas related complication; patients died due to their primary disease. CONCLUSION: Our study shows that with appropriate patient selection, SFVT have low infection rates and patency that is comparable with other access types.

The influence of near-infrared therapy on arteriovenous fistula patency in haemodialysis patients: A multicentre, randomised, controlled clinical trial.

BACKGROUND: Arteriovenous fistula (AVF) is the preferred vascular access for patients undergoing haemodialysis (HD). AVF malfunction remains a major clinical problem and is a significant independent risk factor for death. Although far-infrared (FIR) therapy has been shown to reduce complications and improve the patency rate of AVFs in various studies, it has been cautiously recommended by the Kidney Disease Outcome Quality Initiative (KDOQI) guidelines for AVF care due to insufficient evidence. Therefore, it is necessary to identify more effective methods for preventing AVF dysfunction. Many in vitro studies and few clinical studies have examined the effects of near-infrared (NIR) therapy on the vasculature. This study will examine the effects of NIR therapy on AVF. METHODS: A randomised, controlled, open-label, multicentre trial will compare the effect of NIR on AVF patency after 1 year of therapy with that of a control group of patients with existing AVF. One group of patients received NIR treatment above their AVFs, whereas the control group received regular care. The primary outcome is the primary fistula patency rate within 12 months. In addition, acute changes in inflammatory, vasodilatory and haemodynamic parameters after a single treatment in the first 40 participants will be examined. This study was registered in the Clinical Trials Registry (ChiCTR2300071305) at https://register.clinicaltrials.gov/. DISCUSSIONS: This study will explore the long-term and acute effects of NIR on AVFs. The study findings will provide information that can be used to develop new technical support for the prevention of AVF dysfunction in patients undergoing haemodialysis.

Accuracy of physical examination versus Doppler ultrasonography for determining maturity in postoperative arteriovenous fistula formation.

BACKGROUND: Differentiating between arteriovenous fistula (AVF) maturation and failure can help determine which AVF will undergo successful canulation and which ones will require immediate rescue. METHODS: A prospective observational study was conducted at Vajira Hospital in Bangkok, Thailand, between October 2020-November 2022. A single vascular surgeon performed a physical examination on patients with chronic kidney disease undergoing AVF placement, and a radiologist conducted Doppler ultrasonography during the second and sixth postoperative weeks. Dialysis nurses determined AVF maturity by performing cannulation. The study compared the accuracy of physical examination and Doppler ultrasonography. A model was developed to predict the success of AVF use. RESULTS: Out Of the 125 recruited patients, 81% demonstrate unassisted maturation of their AVF. The male sex and brachiocephalic type are associated with AVF maturation. The physical examination findings of palpable thrill and the absence of a strong pulse at the 6th week show an area under the receiver operating curve (AUC) value of 0.79. Similarly, arterial end-diastolic velocity on ultrasonography at the 6th week also demonstrates a comparable predictive value with an AUC of 0.82 (p = 0.697). Meanwhile, the model that combined end-diastolic velocity and venous volume flow yields the best results for predicting AVF maturation, with an AUC of 0.92. These models provide more accurate predictions compared to physical examination alone (AUC: 0.92 vs. 0.79; p < 0.01). CONCLUSION: Although a prudent physician predicts AVF maturation through a thorough physical examination, Doppler ultrasonography is preferred in anticipating the success of postoperative AVF placement.

Elevated Leukocyte Glucose Index Is Associated with Long-Term Arteriovenous Fistula Failure in Dialysis Patients.

(1) Background: Arteriovenous fistula (AVF) is the preferred type of vascular access for dialysis in patients with end-stage kidney disease (ESKD). However, the primary patency of AVF at one year is under 70% due to several risk factors and comorbidities. Leukocyte glucose index (LGI), a new biomarker based on blood leukocytes and glucose values, has been found to be associated with poor outcomes in cardiovascular disease. The aim of this study is to analyze the impact of LGI on the long-term primary patency of AVF following dialysis initiation. (2) Methods: We conducted a retrospective observational study in which we initially enrolled 158 patients with ESKD admitted to the Vascular Surgery Department of the Emergency County Hospital of Targu Mures, Romania, to surgically create an AVF for dialysis between January 2020 and July 2023. The primary endpoint was AVF failure, defined as the impossibility of performing a chronic dialysis session due to severe restenosis or AVF thrombosis. After follow-up, we categorized patients into two groups based on their AVF status: "functional AVF" for those with a permeable AVF and "AVF failure" for those with vascular access dysfunction. (3) Results: Patients with AVF failure had a higher prevalence of atrial fibrillation (p = 0.013) and diabetes (p = 0.028), as well as a higher LGI value (1.12 vs. 0.79, p < 0.001). At ROC analysis, LGI had the strongest association with the outcome, with an AUC of 0.729, and an optimal cut-off value of 0.95 (72.4% sensitivity and 68% specificity). In Kaplan-Meier survival analyses, patients in the highest tertile (T3) of LGI had a significantly higher incidence of AVF failure compared to those in tertile 1 (p = 0.019). Moreover, we found that patients with higher baseline LGI values had a significantly higher risk of AVF failure during follow-up (HR: 1.48, p = 0.003). The association is independent of age and sex (HR: 1.65, p = 0.001), cardiovascular risk factors (HR: 1.63, p = 0.012), and pre-operative vascular mapping determinations (HR: 3.49, p = 0.037). (4) Conclusions: In conclusion, high preoperative values of LGI are positively associated with long-term AVF failure. The prognostic role of the biomarker was independent of age, sex, cardiovascular risk factors, and pre-operative vascular mapping determinations.

Accuracy of 3.0T magnetic resonance angiography for the detection of arteriovenous fistula dysfunction in hemodialysis patients requiring interventional therapy: a prospective study.

Background: Color Doppler ultrasonography (CDUS) is feasible to detect arteriovenous fistula (AVF) dysfunction in hemodialysis patients but is not sufficient to map the structure of fistula required for interventions. This study is designed to evaluate the diagnostic accuracy of three-dimensional time-of-flight magnetic resonance angiography (TOF-MRA) at 3.0T versus CDUS for AVF dysfunction, by using digital subtraction angiography (DSA) as reference. Methods: This prospective study enrolled 68 consecutive patients with dysfunctional AVF who underwent both CDUS and TOF-MRA at Shanghai Sixth People's Hospital affiliated to Shanghai Jiao Tong University School of Medicine. The analysis of the dysfunctional AVFs was divided into three regions: the feeding artery, fistula and draining veins. In the whole- and per-regional-based analyses, two observers who were blinded to the clinical and DSA results independently analyzed all CDUS and TOF-MRA datasets. The image quality and stenosis severity of the lesions on TOF-MRA were evaluated. A receiver operating characteristic curve was applied to analyze the detection of AVF dysfunction with TOF-MRA. Results: A total of 204 vessel regions were evaluated. The whole-region-based image quality of TOF-MRA was poorer in patients with a total occlusion (1.8±0.8) than in those with stenosis (2.7±0.6, P<0.001). In the whole-region analyses, TOF-MRA had higher sensitivity [99.1% (94.6-100.0%) vs. 82.9% (74.6-89.0%), P<0.001] and similar specificity [93.1% (85.0-97.1%) vs. 94.3% (86.5-97.9%), P=0.755] than CDUS. The per-region-based analyses showed that TOF-MRA yielded higher sensitivity [fistula region, 98.1% (88.4-99.9%) vs. 80.8% (67.0-89.9%); P=0.004; draining vein region, 100.0% (92.5-100.0%) vs. 85.0% (72.9-2.5%); P=0.003] and similar specificity [fistula region, 88.2% (62.3-97.8%) vs. 88.2% (62.3-97.9%); P>0.99; draining vein region, 100.0% (59.8-100.0%) vs. 87.5% (46.7-99.3%); P>0.99] than CDUS. Sensitivity and specificity of TOF-MRA were comparable to those of CDUS in feeding artery region. Conclusions: TOF-MRA is a feasible and accurate method to display AVF dysfunction in hemodialysis patients, and this method might fulfill the endovascular treatment planning requirements.

Minimizing delays to hemodialysis access maturation: A quality improvement analysis.

INTRODUCTION: Pre-operative process optimization can expedite time-to-intervention and reduce overall health care costs. We hypothesized that the longest delay to hemodialysis (HD) access creation would be from pre-operative vessel mapping (mandatory in our practice), and that this would be correlated with increased catheter days. METHODS: One hundred thirty patients (24 inpatients, 106 outpatients) who received initial hemodialysis (HD) access from 01/01/2017 to 12/31/2021, at the Veterans Affairs Puget Sound, Seattle, Washington, were identified. Median time differences between pre-operative events were compared between inpatients and outpatients using the Mann-Whitney U test. Outpatients were then stratified by time of catheter-based HD initiation (no catheter, pre-referral catheter, post-referral catheter) and compared. The impacts of mapping-related delays on catheter use were evaluated using regression. RESULTS: Inpatients had shorter referral to access maturation times (125 days inpatient vs 146 days outpatient; p = 0.03). This was driven by shorter referral to mapping (2 days inpatient vs 27 days outpatient; p < 0.01) and mapping to pre-surgical evaluation (1-day inpatient vs 6 days outpatients; p < 0.01) times. Pre-surgical evaluation to OR times represented the longest pre-operative delay in both groups (51 days inpatient vs 29 days outpatient; p = 0.59). Among outpatients, tunneled catheter placement post-referral resulted in longer maturation times (74 days no catheter vs 67 days pre-referral vs 149 days post-referral; p < 0.01) but not additional pre-operative delays. No trend existed between increased mapping times and catheter-based dialysis duration (R2 = 0.08). CONCLUSION: Preoperative vein mapping contributed up to 21% of referral to maturation times but was not associated with increased tunneled catheter duration. While tunneled catheter placement impacted access maturation it did not cause additional pre-operative delays. Earlier referrals for access creation and reduction of outpatient wait-time from referral to OR and increased AV graft placement may minimize catheter days in our system thereby mitigating the added delays caused by pre-operative vein mapping.

Effect of blood viscosity on the hemodynamics of arteriovenous fistulae based on numerical investigation.

Arteriovenous fistula (AVF) is the most commonly used vascular access for hemodialysis in patients with end-stage renal disease. Vascular diseases such as atherosclerosis and thrombosis, triggered by altered hemodynamic conditions, are the main causes of access failure. Changes in blood viscosity accelerate access dysfunction by affecting local velocities and wall shear stress (WSS) distribution in the circulation. Numerical simulation was employed to analyze and compare the hemodynamic behavior of AVF under different blood viscosities (0.001-0.012 Pa∙s). An idealized three-dimensional model with end-to-side anastomosis was established. Transient simulations were conducted using pulsatile inlet velocity and outflow as boundary conditions. The simulation results reveal the blood flow state of AVF under different viscosity physiological conditions and derive the rule of change. When blood viscosity increases, the local velocity in the disturbed region slows down and the stagnation time becomes longer, resulting in increased deposition of substances. As blood viscosity increases, the level of shear stress on the entire wall of the fistula increases accordingly. WSS values at high viscosities above 0.007 Pa∙s showed significantly larger low-shear regions near the anastomosis and increased chances of inducing atheromatous plaques. This research has revealed the correlation between blood dynamic viscosity and the hemodynamic behavior of AVF. Elevated whole blood viscosity increases the incidence of access obstruction and vascular disease leading to fistula failure. The study provides a basis for optimizing the distribution of hemodynamic parameters in the fistula for hemodialysis patients.

Intraoperative transit time flow measurement predicts maturation of radiocephalic arteriovenous fistulas.

OBJECTIVE: The arteriovenous fistula (AVF) is the first choice for gaining vascular access for hemodialysis. However, 20% to 50% of AVFs fail within 4 months after creation. Although demographic risk factors have been described, there is little evidence on the intraoperative predictors of AVF maturation failure. The aim of this study was to assess the predictive value of intraoperative transit time flow measurements (TTFMs) on AVF maturation failure. METHODS: In this retrospective cohort study, intraoperative blood flow, measured using TTFM, was compared with AVF maturation after 6 weeks in 55 patients. Owing to its significantly higher prevalence and risk of nonmaturation, the radiocephalic AVF (RCAVF) was the main focus of this study. A recommended cutoff point for high vs low intraoperative blood flow was determined for RCAVFs, using a receiver operating characteristic curve. RESULTS: The average intraoperative blood flow in RCAVFs was 156 mL/min. Patients with an intraoperative blood flow equal or lower than the determined cutoff point of 160 mL/min, showed a 3.03 times increased risk of AVF maturation failure after 6 weeks, compared with patients with a higher intraoperative blood flow (P < .001). CONCLUSIONS: The intraoperative blood flow in RCAVFs measured by TTFM provides an adequate means of predicting AVF nonmaturation 6 weeks after surgery. For RCAVFs, a cutoff point for intraoperative blood flow of 160 mL/min is recommended for maximum sensitivity and specificity to predict AVF maturation failure after 6 weeks.

The correlation between self-Hounsfield units and adjacent vertebral fracture after percutaneous vertebral augmentation: a retrospective cohort study.

Background: Adjacent vertebral fracture (AVF) represents a prevalent and challenging complication after percutaneous vertebral augmentation (PVA) treatment for osteoporosis vertebral compressive fracture (OVCF). Lower bone mineral density (BMD) and intervertebral leakage are reportedly independent risk factors for AVF. Vertebral Hounsfield units (HU) measured from computed tomography (CT) scans can evaluate bone quality. This study sought to explore the risk factors associated with AVF and analyze the relationship between AVF and the Hounsfield units of adjacent vertebrae (self-HU) following PVA. Methods: In this retrospective cohort study, we included consecutive OVCF patients who presented to Xuzhou Central Hospital in Jiangsu Province, China from 1 January 2016, to 31 December 2019 for PVA treatment. Clinical and imaging data were collected, and baseline data were recorded. Patients were divided into the AVF group and the no-AVF group based on the presence of AVF during follow-up. Patients in the AVF group were further subdivided into the leakage group and the no-leakage group according to the presence of intervertebral leakage. Age, body mass index (BMI), fracture location, prior fracture, self-HU, and intervertebral leakage were included in univariate logistic regression analysis. Variables with a P value of less than 0.1 were then included in multivariate logistic regression analysis to determine the risk factors for AVF. Kaplan-Meier curves were plotted to assess the effect of intervertebral leakage on AVF using a log-rank test. Results: A total of 460 patients were included in this study and followed up for an average of 50.9 months (range, 37-83 months). Among them, 82 cases (17.83%) developed AVF and were included in the AVF group. Multivariate logistic regression analysis showed that lower self-HU [odds ratio (OR) =0.972, 95% confidence interval (CI): 0.959-0.985, P<0.001] and intervertebral leakage (OR =2.618, 95% CI: 1.415-4.844, P=0.002) were risk factors for AVF following PVA. In the AVF group, 29 patients (35.37%) with intervertebral leakage were included in the leakage group. Patients in the leakage group had a shorter time to AVF (22.07±13.83 vs. 31.42±18.73, P=0.021) and higher self-HU (78.05±16.41 vs. 64.23±20.49, P=0.002) than those in the no-leakage group. Kaplan-Meier curves showed that the fracture-free time was shorter in the leakage group compared to the no-leakage group (log-rank test, P=0.014). Conclusions: Lower self-HU and intervertebral leakage are risk factors for AVF, and higher self-HU may lead to AVF when intervertebral leakage is present.

Analysis of risk factors for late arteriovenous fistula failure and patency rates after angioplasty in hemodialysis patients: a retrospective cohort study.

Background: The incidence of chronic kidney disease (CKD) and end-stage kidney disease (ESKD) is increasing worldwide. Hemodialysis (HD) is the mainstay of renal replacement therapy for patients with ESKD. Risk factors associated with late arteriovenous fistula (AVF) failure in HD patients are poorly investigated. Therefore, the aim of this study was to identify factors associated with late AVF failure in HD patients. Methods: Patients with end-stage renal disease (ESRD) who underwent forearm or upper arm AVF angioplasty at Second Affiliated Hospital of Chongqing Medical University between September 2009 and August 2018 were included. Patients were followed up for 36 months. Baseline characteristics were collected using electronic medical records (EMRs). Variables associated with late AVF failure were identified using Cox proportional hazards models. Results: There were 137 patients (64% male, 36% female) included in this study, with 50 (36.5%) experiencing AVF failure. Univariable log-rank analysis showed that age, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), intact parathyroid hormone (iPTH), albumin (ALB), and AVF patency rate were significantly different between patients who did and did not experience AVF failure. Cox regression analysis showed that CRP [P=0.002, hazard ratio (HR) =2.719, 95% confidence interval (CI) for HR: 1.432-5.164], ESR (P=0.030, HR =2.431, 95% CI: 1.088-5.434), iPTH (P=0.013, HR =0.325, 95% CI: 0.133-0.793), and ALB (P=0.040, HR =0.539, 95% CI: 0.299-0.972) were independently associated with AVF failure. Kaplan-Meier survival analysis showed that the cumulative patency rates of AVF at 6, 12, 18, 24, 30, and 36 months were 84%, 74%, 69%, 64%, 64%, and 64%, respectively. Conclusions: CRP, ESR, iPTH, and ALB were associated with AVF failure and should be used as reference in clinical practice.

Is central venous catheter in haemodialysis still the main factor of mortality after hospitalization?

BACKGROUND: Haemodialysis is the most frequently prescribed Renal Replacement Therapy modality worldwide. However, patients undergoing this therapy have an unpredictable evolution related to vascular access. OBJECTIVE: To determine the factors associated with the mortality and hospitalization rate in haemodialysis patients at a third-level care Centre in the Dominican Republic. METHODS: This was an observational and prospective study involving a cohort of 192 haemodialysis patients. The patient selection was non-probabilistic for convenience, and a direct source questionnaire was applied. RESULTS: Of the 192 patients in the cohort, 103 (53.6%) were hospitalized and evaluated. The most frequent cause of hospitalization was catheter-related bloodstream infections (53.4%). Almost one-third (28.2%) of the hospitalized patients died, mostly due to infections (12.6%). Of those who died 29 patients (90%) had a Central venous catheter (CVC) with a non-tunnelled catheter (NTCVC) (65.5%); having an NTC CVC makes a patient 85.5 times more likely to be hospitalized than patients with arteriovenous fistulas. CONCLUSION: Vascular access plays a predominant role in the hospitalization and mortality rates in haemodialysis. Patients with an arteriovenous fistula obtained significantly better outcomes than those with central venous catheters.