Impact of Body Mass Index on Outcomes of Autogenous Fistulas for Hemodialysis Access

Risk Factor Analysis in Vascular Access Complications for Hemodialysis Patients

Background: Chronic kidney disease (CKD) and renal failure remain critical global health challenges, with vascular access complications posing significant obstacles in hemodialysis management. Methods: This study investigates the early and late complications associated with vascular access procedures in a cohort of 1334 patients from Timiș County Emergency Clinical Hospital. Patients were categorized into early complications, occurring within 30 days postoperatively, and late complications, developing beyond this period. Demographic data, comorbidities, and lifestyle factors, including age, gender, body mass index (BMI), smoking status, hypertension, diabetes, and cardiovascular disease (CVD), were recorded and analyzed. Early complications included thrombosis, hemorrhage, edema, and non-maturation, while late complications involved thrombosis, aneurysmal dilation, venous hypertension, and infections. Results: Hemorrhage (32.3%) and thrombosis (30.8%) were the most prevalent early complications, influenced significantly by diabetes and hypertension. Non-maturation showed a strong association with diabetes and cardiovascular disease (odds ratio: 1.70). For late complications, thrombosis was most frequent, with hypertensive patients exhibiting increased risk (relative risk: 1.18). BMI was a significant factor in both early and late complications. Risk analysis using odds ratios and relative risks revealed distinct patterns of complication risks based on comorbidities and smoking status. Logistic regression modeling for thrombosis demonstrated moderate predictive accuracy (AUC: 0.64). Conclusions: These findings suggest that clinical interventions, such as stricter perioperative glycemic and blood pressure control, and personalized surgical strategies for patients with high BMI or comorbidities, could significantly reduce the incidence of vascular access complications and improve outcomes in this high-risk population.

30-Day Risk Score for Mortality and Stroke in Patients with Carotid Artery Stenosis Using Artificial Intelligence Based Carotid Plaque Morphology

BACKGROUND

The gold standard for determining carotid artery stenosis intervention is based on a combination of percent stenosis and symptomatic status. Few studies have assessed plaque morphology as an additive tool for stroke prediction. Our goal was to create a predictive model and risk score for 30-day stroke and death inclusive of plaque morphology.

METHODS

Patients with a computed tomographic angiography head/neck between 2010 and 2021 at a single institution and a diagnosis of carotid artery stenosis were included in our analysis. Each computed tomography was used to create a three-dimensional image of carotid plaque based off image recognition software. A stepwise backward regression was used to select variables for inclusion in our prediction models. Model discrimination was assessed with area under the receiver operating characteristic curves (AUCs). Additionally, calibration was performed and the model with the least Akaike Information Criterion (AIC) was selected. The risk score was modeled from the Framingham Study. Primary outcome was mortality/stroke.

RESULTS

We created 3 models to predict mortality/stroke from 366 patients: model A using only clinical variables, model B using only plaque morphology and model C using both clinical and plaque morphology variables. Model A used age, sex, peripheral arterial disease, hyperlipidemia, body mass index (BMI), chronic obstructive pulmonary disease (COPD), and history of transient ischemia attack (TIA)/stroke and had an AUC of 0.737 and AIC of 285.4. Model B used perivascular adipose tissue (PVAT) volume, lumen area, calcified volume, and target lesion length and had an AUC of 0.644 and AIC of 304.8. Finally, model C combined both clinical and software variables of age, sex, matrix volume, history of TIA/stroke, BMI, PVAT, lipid rich necrotic core, COPD and hyperlipidemia and had an AUC of 0.759 and an AIC of 277.6. Model C was the most predictive because it had the highest AUC and lowest AIC.

CONCLUSIONS

Our study demonstrates that combining both clinical factors and plaque morphology creates the best predication of a patient's risk for all-cause mortality or stroke from carotid artery stenosis. Additionally, we found that for patients with even 3 points in our risk score model has a 20% chance of stroke/death. Further prospective studies are needed to validate our findings.

Factors affecting suboptimal maturation of autogenous arteriovenous fistula in elderly patients with diabetes:A narrative review

Autogenous arteriovenous fistula (AVF) is considered the preferred vascular access choice for individuals undergoing maintenance hemodialysis (MHD) and is widely utilized in China, as reported by the Dialysis Outcomes and Practice Patterns Study. Despite its popularity, the significant incidence of poor AVF maturation often leads to the need for central venous catheter insertion, increasing the risk of complications like superior vena cava stenosis and catheter-related infections, which in turn raises the overall mortality risk. With the prevalence of diabetes rising globally among the elderly and diabetic kidney disease being a leading cause of end-stage renal disease necessitating renal replacement therapy, our retrospective review aims to explore the various factors affecting AVF maturation in this specific patient population. While there have been numerous studies examining AVF complications in MHD patients, including issues like failure, patency loss, stenosis, thrombosis, poor maturation, and other influencing factors, there remains a gap in large-scale clinical studies focusing on the incidence and risk factors for immature AVF specifically in elderly diabetic patients. This paper delves into the pathophysiological mechanisms, diagnostic criteria, and unique considerations surrounding AVF maturation in elderly diabetic patients, distinguishing them from the general population. Our literature review reveals that elderly diabetic patients exhibit a higher risk of AVF immaturity compared to the general population. Additionally, there exists a continuing discourse regarding several aspects related to this group, including the choice of dialysis access, timing of AVF surgery, and surgical site selection. Furthermore, we delve into the management strategies for vascular access within this specific group with the goal of providing evidence-based guidance for the establishment and maintenance of functional vascular access in elderly diabetic patients.

Midterm outcomes of endoscopic-assisted brachial-basilic arteriovenous fistula creation

Endoscopic vein harvest remains underused in single-stage brachial-basilic arteriovenous fistula creation. We analyzed our results with the use of this technique in a cohort of predominantly obese (body mass index ≥30 kg/m2) patients. Demographics, intraoperative details, and outcomes for all consecutive patients who underwent single-stage endoscopic-assisted brachial-basilic arteriovenous fistula creation between 2020 and 2022 at a single institute were analyzed retrospectively. The primary outcomes were technical success, fistula maturation, and primary assisted and secondary patency rates. Of the 11 patients (7 men; mean age, 62 ± 11.6 years), 7 (64%) already required dialysis at referral. The mean body mass index was 34 ± 7 kg/m2, 64% were obese, and an additional 27% were overweight. The medical comorbidities included hypertension in 11 patients (100%), diabetes in 7 (64%), and smoking in 8 (73%). Technical success was 100%, with no intraoperative complications. The median procedural length was 231 minutes (range, 183-302 minutes). Early complications in two patients (18%) included bleeding of the venous side branch requiring ligation and the loss of thrill requiring division of a tethering bridge of a large tributary. The maturation rate was 100%, and the brachial-basilic arteriovenous fistula was successfully accessed in all patients who required dialysis. At 12 months, the primary assisted and secondary patency rates were 90% ± 10% and 100%, respectively. Reintervention in seven patients (64%) included successful angioplasty in four, thrombectomy in two, and aneurysm resection with an interposition graft in one patient. Endoscopic vein harvest can be used for single-stage brachial-basilic arteriovenous fistula creation with good technical success and favorable maturation and patency rates, even for obese patients.

Predictors of Arteriovenous Fistula Maturation among Patients with Severe Obesity

BACKGROUND

There is an increasing prevalence of obesity among patients who develop end-stage renal disease and require dialysis. While referrals for arteriovenous fistulas (AVFs) among patients with class 2-3 obesity (i.e., body mass index [BMI] ≥ 35) are increasing, it is unclear what type of autogenous access is most likely to mature in this patient population. This study was designed to evaluate factors that impact maturation of AVF among patients with class ≥2 obesity.

METHODS

We retrospectively reviewed AVFs created at a single center from 2016 to 2019 for patients who had undergone dialysis within the same healthcare system. Ultrasound studies were used to evaluate factors that defined functional maturation, including diameter, depth, and volume flow rates through the fistula. Logistic regression models were used to evaluate the risk-adjusted association between class ≥2 obesity and functional maturation.

RESULTS

A total of 202 AVFs [radiocephalic (24%), brachiocephalic (43%), and transposed brachiobasilic (33%)] were created during the study period, of which 53 (26%) patients had a BMI >35. Functional maturation was significantly lower among patients with class ≥2 obesity undergoing brachiocephalic (58% obese versus 82% normal-overweight; P = 0.017), but not radiocephalic or brachiobasilic AVFs. This was primarily a result of excessive AVF depth in severely obese patients (9.6 ± 4.0 mm obese versus 6.0 ± 2.7 mm normal-overweight; P < 0.001), whereas there was no significant difference found in average volume flow or AVF diameter between groups. In risk-adjusted models, a BMI ≥35 was associated with a significantly lower likelihood of achieving AVF functional maturation (odds ratio: 0.38; 95% confidence interval: 0.18-0.78; P = 0.009) after controlling for age, sex, socioeconomic status, and fistula type.

CONCLUSIONS

Patients with a BMI >35 are less likely to mature AVFs after creation. This principally affects brachiocephalic AVFs and occurs because of increased fistula depth as opposed to diameter or volume flow parameters. These data can help guide decision-making when planning AVF placement in severely obese patients.

Associations between body mass index and all-cause mortality: A systematic review and meta-analysis

Fasting insulin and c-reactive protein confound the association between mortality and body mass index. An increase in fat mass may mediate the associations between hyperinsulinemia, hyperinflammation, and mortality. The objective of this study was to describe the "average" associations between body mass index and the risk of mortality and to explore how adjusting for fasting insulin and markers of inflammation might modify the association of BMI with mortality. MEDLINE and EMBASE were searched for studies published in 2020. Studies with adult participants where BMI and vital status was assessed were included. BMI was required to be categorized into groups or parametrized as non-first order polynomials or splines. All-cause mortality was regressed against mean BMI squared within seven broad clinical populations. Study was modeled as a random intercept. β coefficients and 95% confidence intervals are reported along with estimates of mortality risk by BMIs of 20, 30, and 40 kg/m2 . Bubble plots with regression lines are drawn, showing the associations between mortality and BMI. Splines results were summarized. There were 154 included studies with 6,685,979 participants. Only five (3.2%) studies adjusted for a marker of inflammation, and no studies adjusted for fasting insulin. There were significant associations between higher BMIs and lower mortality risk in cardiovascular (unadjusted β -0.829 [95% CI -1.313, -0.345] and adjusted β -0.746 [95% CI -1.471, -0.021]), Covid-19 (unadjusted β -0.333 [95% CI -0.650, -0.015]), critically ill (adjusted β -0.550 [95% CI -1.091, -0.010]), and surgical (unadjusted β -0.415 [95% CI -0.824, -0.006]) populations. The associations for general, cancer, and non-communicable disease populations were not significant. Heterogeneity was very large (I2  ≥ 97%). The role of obesity as a driver of excess mortality should be critically re-examined, in parallel with increased efforts to determine the harms of hyperinsulinemia and chronic inflammation.

The Effect of Obesity on Outcomes After Arteriovenous Fistulae Creation: A Systematic Review

BACKGROUND

Establishing reliable vascular access is critical for hemodialysis in end-stage renal disease (ESRD). In recent years, the global health burden of ESRD has grown, matched by a rise in prevalence of obesity. Currently, more and more arteriovenous fistulae (AVFs) are being created for obese patients with ESRD. This is a growing concern as creating arteriovenous (AV) access in obese ESRD patients can be more challenging and may be associated with poorer outcomes.

METHODS

We performed a literature search with multiple electronic databases. We included studies that compared outcomes after autogenous upper extremity AVF creation between obese and nonobese patients. The relevant outcomes were postoperative complications, outcomes related to maturation, outcomes related to patency, and outcomes related to reintervention.

RESULTS

We included 13 studies with a total of 305,037 patients. We found a significant association between obesity and poorer early and late AVF maturation. Obesity was also strongly associated with lower primary patency rates and a higher need for reintervention.

CONCLUSIONS

This systematic review found that higher body mass index and obesity are associated with poorer AVF maturation outcomes, poorer primary patency, and higher reintervention rates.

Hemodialysis Access Type and Access Patency Loss: An Observational Cohort Study

Rationale & Objective

Access patency outcomes for arteriovenous fistulas (AVFs) as compared with arteriovenous grafts (AVGs) in patients receiving hemodialysis (HD) who have achieved a functioning permanent access are not fully explored.

Study Design

Observational cohort study.

Setting & Population

Fee-for-service Medicare beneficiaries aged ≥18 years with kidney failure who were newly using a permanent access for maintenance HD from the United States Renal Data System (2010-2015). Patients using an oral anticoagulant were excluded.

Exposure

AVG or AVF.

Outcomes

Loss of primary unassisted, primary assisted, and secondary patency.

Analytical Approach

Outcomes were characterized using cumulative incidence curves, and HRs adjusted for sociodemographic and clinical factors were estimated for the comparison of AVF versus AVG.

Results

The cohort included 60,329 and 17,763 patients newly using an AVF and AVG, respectively, for HD. Over 3 years of follow-up, AVG users, compared to AVF users, had a higher cumulative incidence of loss of primary unassisted patency (87% vs 69%; HR, 1.56; 95% CI, 1.52-1.60), loss of primary assisted patency (69% vs 25%; HR, 3.79; 95% CI, 3.67-3.92), and loss of secondary patency (22% vs 10%; HR, 2.03; 95% CI, 1.92-2.16). Stratified analyses revealed differences by subgroups; in particular, incidence of patency loss was higher among patients who underwent prior interventions to maintain prefunctional access patency and Black patients.

Limitations

This analysis focused on outcomes occurring after first successful use of a permanent access and thus does not inform about risk of patency loss during access maturation.

Conclusions

Among patients with kidney failure who successfully used a permanent access for HD, patency loss was consistently substantially higher in those using AVGs compared with AVFs. New interventions, such as prophylactic drugs, are needed to improve access longevity and reduce the need for invasive interventions, particularly among patients unable to receive a fistula.

Association of body mass index with outcomes after thoracic endovascular aortic repair in the vascular quality initiative

OBJECTIVE

Although several studies have evaluated the impact of obesity on outcomes after abdominal aortic aneurysm repair, literature examining this association in thoracic endovascular aortic repair (TEVAR) is sparse. Here, we use a multi-institutional, international database to assess the role of body mass index (BMI) on adverse outcomes in patients who underwent TEVAR for descending thoracic aortic aneurysms (DTAA) and type B dissections (TBD).

METHODS

A retrospective review of all patients who underwent TEVAR for DTAA or TBD from August 2014 to August 2020 was performed. Patients who were underweight (BMI <18.5 kg/m²) or obese (BMI ≥30 kg/m²) were compared with those of normal weight (≥18.5 to <30 kg/m²). Adjustment for confounding was done with multivariable logistic regression or Cox proportional hazards regression as appropriate for studying postoperative or 1-year outcomes. Primary outcomes were 30-day and 1-year mortality. Other outcomes included any postoperative complication, stroke, and spinal cord ischemia.

RESULTS

A total of 3423 participants were included in the study, of whom 3.3% (n = 113) were underweight, 65.9% (n = 2253) had normal weight, and 30.8% (n = 1053) were obese. Compared with normal weight, there was no significant difference in 30-day mortality in underweight patients (odds ratio [OR], 1.81; 95% confidence interval [CI], 0.80-4.14; P = .156). Obese patients who underwent TEVAR for TBD had a 2.7-fold increase in the odds of 30-day mortality compared with normal weight (OR, 2.67; 95% CI, 1.52-4.68; P = .001). Obese and normal weight patients with DTAA had equivalent odds of 30-day mortality (OR, 1.32; 95% CI, 0.79-2.23; P = .292). The adjusted hazard of 1-year mortality was 2-fold higher in underweight patients compared with normal weight (hazard ratio, 2.15; 95% CI, 1.41-3.29; P < .001), driven by a higher risk of mortality among patients with thoracic aortic aneurysm (OR, 2.62; 95% CI, 1.63-4.21; P < .001). There was no significant difference in 1-year mortality risk between normal weight and obesity in both DTAA (OR, 0.77; 95% CI, 0.54-1.09; P = .146) and TBD (OR, 1.26; 95% CI, 0.85-1.86; P = .248).

CONCLUSIONS

In this study, obese patients who underwent TEVAR for DTAA had comparable 30-day and 1-year mortality risk as normal weight individuals. Obese patients who underwent TEVAR for TBD demonstrated a 2.7-fold increase in the odds of 30-day mortality, but equivalent mortality risk as normal weight patients at 1 year. TEVAR represents a safe minimally invasive option for treatment of DTAA in obese patients. Future work should be directed toward minimizing perioperative mortality among patients with TBD to optimize TEVAR outcomes.

Repeated Endovascular Interventions Are Worthwhile, Even After Thrombosis, to Maintain Long-Term Use of Autogenous Dialysis Fistulas

OBJECTIVES

Patients often require multiple access re-interventions to improve fistula patency and the overall usable lifespan of autogenous arteriovenous fistula (aAVF). There is no consensus on the appropriate number of re-interventions after which an access should be abandoned and new access placed. We evaluated whether repeated endovascular interventions for failing/failed aAVF are worthwhile or futile.

METHODS

A retrospective review was performed on aAVFs created between 2009-2014. Fistula function was evaluated until January 2017. Functional fistula patency (FFP) was defined as the total time of functional fistula use for hemodialysis, from time of cannulation to time of measurement or fistula abandonment, including all interventions performed to maintain/reestablish patency. Primary outcomes were FFP duration and number of post-dialysis interventions.

RESULTS

The study included 163 patients. Mean age was 67 (SD = 15.03). The only variable statistically different between functional fistulas and abandoned fistulas was obesity (p = 0.03). At the end of the study period, 145 (89.0%) patients continued to have functional fistulas, and 73 (44.8%) patients died, but had functional fistulas at time of death. Median FFP for the functional group was 3.18 years (range 0.01-7.01 years) and median number of interventions was 1 (range 0-13). In 18 patients (11%), the fistula was abandoned, most commonly due to thrombosis (47.1%), followed by infection (23.5%). No fistula was abandoned because of an unacceptable rate of reintervention. Median FFP in the abandoned group was 0.91 years (range 0.03-5.30 years), and median number of interventions was 0 (range of 0-5).

CONCLUSIONS

Through repeated interventions on aAVFs, none of the patients in our study exhausted all hemodialysis access options prior to transplantation, death or loss to follow-up. These results may indicate repeated and/or more frequent revisions do not negatively affect the FFP nor do they increase the overall risk for abandonment of aAVFs.

Management of Obesity in Adults with CKD

Obesity is a leading public health problem that currently affects over 650 million individuals worldwide. Although interest in the adverse effects of obesity has grown exponentially in recent years, less attention has been given to studying its management in individuals with CKD. This relatively unexplored area should be considered a high priority because of the rapid growth and high prevalence of obesity in the CKD population, its broad impact on health and outcomes, and its modifiable nature. This article begins to lay the groundwork in this field by providing a comprehensive overview that critically evaluates the available evidence related to obesity and kidney disease, identifies important gaps in our knowledge base, and integrates recent insights in the pathophysiology of obesity to help provide a way forward in establishing guidelines as a basis for managing obesity in CKD. Finally, the article includes a kidney-centric algorithm for management of obesity that can be used in clinical practice.

Impact of clinical parameters and vascular haemodynamics on arterio-venous fistula maturation in patients with end stage renal disease: A prospective study on Indian patients

BACKGROUND

About 18%-65% of Arterio-Venous fistula (AVF) made to facilitate haemodialysis in end stage renal disease patient fail to mature. This study was designed to evaluate the impact of clinical parameters and vascular haemodynamics on maturation of AVF on Indian patients.

MATERIAL AND METHODS

This was a prospective observational study. Eligible patients' clinical profiles and vascular haemodynamics by Doppler ultrasonography were noted. All patients underwent radio-cephalic AVF on the non-dominant arm under local anaesthesia. Clinical definition was used to assess success rate of AVFs which is defined as successful six settings of satisfactory dialysis. Data were analysed using Stata/12.0 software. Independent t-test, chi-square test, logistic regression analysis and multivariate analysis were used. The p-value of <0.05 was considered significant.

RESULTS

A total of 205 patients were enrolled and analysed. Among clinical factors, age, sex, serum creatinine, hypertension had no significant association with failure (p = 0.5, 0.08, 0.76 and 0.74). Patient's BMI and presence of diabetes had significant impact on outcome (p < 0.001 and 0.02 respectively). Among vascular haemodynamics, radial vein diameter of >2.5 mm and radial artery flow rate >40 ml/min had no significant association with failure (p = 0.12 and 0.28). Diameter of radial artery (>2 mm) and intra-operatively immediate thrill were independent predictor of success (p = 0.002 and <0.001).

CONCLUSION

In the present study rate of fistula, maturation was 73.2% without any post-operative radiological intervention. Radial artery diameter >2 mm and presence of immediate thrill post-operatively were significantly associated with successful cannulation.