Quantitative physical examination indicators to detect patients with stenosis at a high risk of thrombosis at hemodialysis vascular access sites: A retrospective case-control study.

BACKGROUND: Quantitative physical examination (PE) indicators, including palpable pulsatility length and outflow scores, can be used to quantify stenosis severity at hemodialysis vascular access sites. It is known that the risk of high-shear-related thrombosis is increased when the minimal luminal diameter (MLD) of stenosis decreases. At present, MLD is measured using sonography or angiography. This study sought to determine the relationship between quantitative PE indicators and MLD and report their diagnostic performance in detecting patients with stenosis at a high risk of thrombosis. METHODS: We performed a retrospective case-control study using routinely collected data. We used the post-stenosis palpable pulsatility length (sPPL) and pulse-and-thrill based outflow score to assess the severity of AVF inflow and outflow stenosis, respectively. We recorded paired quantitative PE indicators and MLD before and after angioplasty in patients enrolled over a 4-month period. RESULTS: A total of 249 paired PE indicators and MLD measurements were obtained from 163 patients. A receiver operating characteristic curve analysis showed that an MLD cutoff value of <1.55 mm and an MLD of <1.95 mm discriminated sPPL = 0 and PESOS (physical examination significant outflow stenosis)/1- of the outflow score, respectively, from all other measurements, with the area under the curve values of 0.8922 and 0.9618, respectively. With sPPL = 0 and PESOS/1- of the outflow score as diagnostic tools to detect inflow stenosis with an MLD of ⩽1.5 mm and outflow stenosis with an MLD of ⩽1.9 mm at vascular access sites, sensitivity = 86.00% and 88.46%; specificity = 97.67% and 92.11%; positive predictive values of 97.73% and 92.00% and negative predictive values of 85.71% and 88.61%, respectively, were observed. CONCLUSIONS: Our preliminary results showed that physical examination can potentially be a diagnostic tool in detecting patients with stenosis who are at a high risk of thrombosis at hemodialysis vascular access sites with high diagnostic accuracy.

Combined cardiomegaly and aortic arch calcification predict mortality in hemodialysis patients.

INTRODUCTION: This study aimed to investigate the relationship between cardiomegaly and aortic arch calcification (AAC) and overall/cardiovascular mortality in hemodialysis patients. METHODS: We conducted a retrospective cohort study and enrolled patients who underwent initial hemodialysis. Cardiomegaly and AAC were determined by chest radiography and classified into four groups according to cross-classification of cardiothoracic ratio (CTR) of 0.5 and lower/higher grade AAC (LGAAC/HGAAC). The relationship between these groups and mortality was then analyzed by Cox proportional hazards model. RESULTS: In multivariate Cox regression analysis, those in CTR ≤ 0.5 and HGAAC [hazard ratio (95% confidence interval): 2.07 (1.14-3.77)], CTR > 0.5 & LGAAC [3.60 (2.07-6.25)] and CTR > 0.5 & HGAAC [3.42 (2.03-5.77)] were significantly associated with overall mortality; while those in CTR > 0.5 & LGAAC [2.81 (1.28-6.19)] and CTR > 0.5 & HGAAC [2.32 (1.09-4.95)] were significantly related to cardiovascular mortality. CONCLUSION: Combined cardiomegaly and AAC predicted overall and cardiovascular mortality in hemodialysis patients.

Association of early failure of arteriovenous fistula with mortality in hemodialysis patients.

Arteriovenous fistula (AVF) is prone to early dysfunction and relates to poor outcome. However, little is known about the role of early AVF dysfunction as an independent risk factor for death in hemodialysis patients. A retrospective cohort study was performed using data of patients who underwent initial AVF surgery at a single institution. Demographic, clinical, biochemistry and AVF parameters were extracted from the electronic records, and the association between these variables and mortality was analyzed by Cox proportional hazards model. A total of 501 patients on hemodialysis (63.4 ± 12.7 years, 57.3% male) were included, and the median observation period was 3.66 years. In multivariate analysis, early failure of AVF (hazard ratio (95% confidence interval): 1.54 (1.06-2.24); p = 0.023) was associated with overall mortality but not cardiovascular mortality. Other identified predictors of overall mortality included older age, peripheral artery disease (PAD), cardiomegaly, higher white blood cell (WBC) count and corrected calcium level, and lower total cholesterol level, while predictors of cardiovascular mortality included older age, coronary artery disease (CAD), PAD and lower hemoglobin level. In conclusion, patients with early AVF failure were associated with increased risk of overall mortality.

Factors affecting patency of arteriovenous fistula following first percutaneous transluminal angioplasty.

BACKGROUND: Percutaneous transluminal angioplasty (PTA) has generally replaced surgical procedures to treat arteriovenous fistula (AVF) dysfunction, but the predictors of post-intervention patency are highly variable. This study aimed to determine predictors of primary patency following PTA of dysfunctional AVF. MATERIALS AND METHODS: Retrospective analysis of first-time PTA of 307 AVF in 307 patients (171 males, mean age 64.3 ± 12.4 years). Demographic, clinical, anatomical and medication variables were reviewed and subjected to univariate and multivariate Cox regression analysis. RESULTS: The post-intervention primary patency rates at 6, 12, 24, and 36 months were 76.3%, 58.3%, 43.2%, and 38.2%, respectively. The higher aortic arch calcification (AAC) grade patients were older, had higher incidence of comorbidities and cardiomegaly, and younger AVF age, but their dialysis vintage term was shorter and diastolic blood pressure was lower, and the maximum diameter of balloon angioplasty was mostly ≤ 6 mm, and had lower phosphorus level and less calcium-containing phosphate binder use. In multivariate Cox proportional hazard analysis, the presence of higher AAC grade [hazard ratio (95% confidence interval): (1.46 (1.02-2.09); p = 0.037)] and stenosis at upper arm [1.76 (1.16-2.67); p = 0.008] were associated with shorter post-intervention primary patency. CONCLUSION: In conclusion, higher AAC grade and anatomic factor related to the location of AVF (upper arm) were the important predictors of AVF dysfunction after PTA. These results could assist in tailoring surveillance programs and performing appropriate interventions for risky AVF.

Quantification of the severity of outflow stenosis of hemodialysis fistulas with a pulse- and thrill-based scoring system.

BACKGROUND: Hyper-pulsatility of hemodialysis arteriovenous fistula (AVF) is the basic physical examination finding when there is outflow stenosis. The arm elevation test can also be utilized to detect outflow stenosis. If there is no significant outflow stenosis, the AVF should collapse, at least partially, because of the effect of gravity when the AVF-bearing arm is elevated to a level above that of the heart. However, if there is significant outflow stenosis, the portion of the AVF downstream of the stenosis will collapse, while the portion upstream of the stenosis will remain distended (Clin J Am Soc Nephro 8:1220-7, 2013). In our daily practice, when performing the arm elevation test, we not only observe the collapsibility of the access outflow but also palpate the outflow to identify a background thrill that sometimes disappears with the arm at rest, only to reappear when the arm is elevated. If there is no thrill upon arm elevation, we assume that the outflow stenosis is severe and refer to this condition as "physical examination significant outflow stenosis" (PESOS). The aim of this study is to characterize PESOS using percentage stenosis and Doppler flow parameters. METHODS: We performed a case-control study using data collected prospectively between June 2019 and December 2019. A pulse- and thrill-based score system was developed to assess the severity of AVF outflow stenosis. We recorded the outflow scores and Doppler measurements performed in 84 patients with mature fistulas over a 6-month period. Angiograms were reviewed to determine the severity of outflow stenosis, which was assessed by calculation of percentage stenosis. RESULTS: Receiver operating characteristic analysis showed that a cutoff value of ≥74.44% stenosis discriminated PESOS from other AVF outflow scores, with an area under the curve of 0.9011. PESOS diagnosed cases with ≥75% outflow stenosis in an AVF, with a sensitivity of 80.39%, a specificity of 78.79%, a positive predictive value of 85.42%, and a negative predictive value of 72.22%. CONCLUSIONS: PESOS can be used to diagnose ≥75% outflow stenosis in an AVF, with or without a significant collateral vein, and its diagnostic accuracy is high. The use of PESOS as an indicator for treatment implies that physical examination may represent a useful surveillance tool.

Measuring the palpable pulsatility length as a physical examination test in defining the severity of inflow stenosis for hemodialysis fistulas.

BACKGROUND: Pulsatility is an important property of hemodialysis arteriovenous fistulas (AVF) and can be perceived by the fingers as a gradual decrease in strength downstream from the anastomosis along the main trunk of the fistula. The distance from the point at which the pulse becomes imperceptible to the anastomosis is termed the palpable pulsatility length (PPL); we considered this length may play a role in assessing the severity of inflow stenosis for hemodialysis fistulas. METHODS: This study was performed by retrospective analysis of routinely collected data. Physical examinations and fistula measurements were performed in a selected population of 76 hemodialysis patients with mature fistulas during half a year. Fistula measurements included the PPL before and after treatment and the distance between the anastomosis and the arterial cannulation site (aPump length). The aPump index (API) was calculated by dividing the PPL by the aPump length. Angiograms were reviewed to determine the location and severity of stenosis. PPL and API were used to detect the critical inflow stenosis, which indicates severe inflow stenosis of an AVF. RESULTS: Receiver operating characteristic analysis showed that the area under the curve was 0.895 for API and 0.878 for PPL. A cutoff value of API < 1.29 and PPL < 11.0 cm were selected to detect the critical inflow stenosis. The sensitivity was 96.0% versus 80.0% and specificity was 84.31% versus 84.31% for API and PPL, respectively. CONCLUSIONS: PPL and API are useful tools in defining the severity of pure inflow stenosis for mature AVFs in the hands of trained examiners with high sensitivity and specificity.

Aortic Arch Calcification as a Predictor of Repeated Arteriovenous Fistula Failure within 1-Year in Hemodialysis Patients.

OBJECTIVES: The aim of the study was to identify the factors associated with repeated arteriovenous fistula (AVF) failure within 1-year, especially the impact of aortic arch calcification (AAC) on patency of AVF. MATERIALS AND METHODS: We retrospectively assessed chest radiography in hemodialysis patients who had undergone initial AVF. The extent of AAC was categorized into four grades (0-3). The association between AAC grade, other clinical variables, and repeated failure of AVF was then analyzed by binary logistic regression analysis. RESULTS: This study included 284 patients (158 males, mean age 61.7 ± 13.1 years). Patients with higher AAC grade were older, had more frequently diabetes mellitus and cardiovascular disease, had lower diastolic blood pressure, and had higher corrected calcium and lower intact parathyroid hormone levels. In multivariate analysis, the presence of higher AAC grade (odds ratio (95% confidence interval): 2.98 (1.43-6.23); p = 0.004), lower mean corrected calcium (p = 0.017), and mean serum albumin level (p = 0.008) were associated with repeated failure of AVF. CONCLUSIONS: The presence of higher AAC grade, lower mean corrected calcium and mean serum albumin level were independently associated with repeated AVF failure within 1 year in hemodialysis patients.

Aortic Arch Calcification Predicts Patency Loss of Arteriovenous Fistula in End-Stage Renal Disease Patients.

Aortic arch calcification (AAC) is recognized as an important cardiovascular risk factor in patients with end-stage renal disease (ESRD). The aim of the study was to evaluate the impact of AAC grade on patency rates of arteriovenous fistula (AVF) in this specific population. The data of 286 ESRD patients who had an initial AVF placed were reviewed. The extent of AAC identified on chest radiography was divided into four grades (0-3). The association between AAC grade, other clinical factors, and primary patency of AVF was then analyzed by Cox proportional hazard analysis. The multivariate analysis demonstrated that the presence of AAC grade 2 (hazard ratio (95% confidence interval): 1.80 (1.15-2.84); p = 0.011) and grade 3 (3.03 (1.88-4.91); p < 0.001), and higher level of intact-parathyroid hormone (p = 0.047) were associated with primary patency loss of AVF. In subgroup analysis, which included AVF created by a surgeon assisted with preoperative vascular mapping, only AAC grade 3 (2.41 (1.45-4.00); p = 0.001), and higher intact-parathyroid hormone (p = 0.025) level were correlated with AVF patency loss. In conclusion, higher AAC grade and intact-parathyroid hormone level predicted primary patency loss of AVF in an ESRD population.

Risk Factors for Early Failure of Arteriovenous Vascular Access Among Patients With Type 2 Diabetes Mellitus.

The aim of the study was to identify the potential risk factors for early arteriovenous access failure in a diabetic population. The data of 223 end-stage renal disease (ESRD) patients with type 2 diabetes who had an arteriovenous fistula (AVF) or arteriovenous graft (AVG) placed as their initial vascular accesses were retrospectively reviewed. The association between clinical factors and risk for early failure was then analyzed. In multivariate analysis, the predictors associated with early failure were female gender (odds ratio (95% confidence interval): 2.52 (1.32-4.81); P = 0.005), AVF with prior peritoneal dialysis (3.26 (1.05-10.11); P = 0.039), and lower hemoglobin level (P = 0.015). The results of significant predictors in the AVF group remained similar to the entire study population. In conclusion, there was an association of female gender, AVF with prior peritoneal dialysis and lower hemoglobin level with early arteriovenous access failure in a diabetic ESRD population.

Preoperative and Intraoperative Factors for Early Failure of Native Arteriovenous Fistulas.

The aim of the study was to assess the potential predictive factors for early arteriovenous fistula (AVF) failure following the fistula first initiative. We retrospectively reviewed the data of 159 end-stage renal disease (ESRD) patients who underwent AVF creation. The preoperative factors such as demographic, comorbidity condition, laboratory parameters and medication, and intraoperative or surgical-related factors were assessed. In multivariate logistic regression analysis, significant predictive factors of early AVF failure were female gender (odds ratio (95% confidence interval): 2.63 (1.19-5.81); P = 0.017), higher body mass index (P = 0.038), and lower hemoglobin level (P = 0.048), while adjusting for preoperative factors or all factors. For adjusting of intraoperative factors, reduced venous diameter (P = 0.056) tended to be associated with early AVF failure. In conclusion, female gender, higher body mass index and lower hemoglobin level predicted the occurrence of early AVF failure in ESRD patients.

Factors related to nephrotic-range proteinuria in late-stage chronic kidney disease patients with diabetes mellitus.

PURPOSE: Diabetic nephropathy and proteinuria are important risk factors for both end-stage renal disease and cardiovascular events. The present study aimed to identify the factors associated with nephrotic-range proteinuria in patients with advanced diabetic nephropathy. METHODS: This cross-sectional study enrolled 386 diabetic patients with chronic kidney disease (CKD) stages 3-5, from our outpatient Department of Nephrology. Urinary protein-to-creatinine ratio was recorded. Additionally, other laboratory parameters, body mass index, blood pressure, comorbidities, and medications were also reviewed. RESULTS: The mean age of the patients was 65.1 ± 11.6 years. Among patients with CKD stage 3 and 4, the odds ratio (OR) for nephrotic-range proteinuria in relation with systolic blood pressure significantly increased starting from 121 mmHg (OR 7.04 and 11.79 for systolic blood pressure of 121-140 and ≥141 mmHg, respectively, in comparison with systolic blood pressure below 121 mmHg). In addition, serum phosphorus ≥4.7 mg/dl was associated with significantly higher risk (OR 15.45) for severe proteinuria, compared with a phosphorus level ≤2.6 mg/dl. Finally, hypertriglyceridemia ≥241 mg/dl was also associated with higher OR for severe proteinuria, compared with a triglyceride level ≤200 mg/dl. Similar associations were found in patients with CKD stage 5. CONCLUSIONS: Higher systolic blood pressure, serum phosphorus, and triglyceride levels are associated with nephrotic-range proteinuria in patients with diabetic nephropathy and CKD stage 3-5. Further studies should clarify whether a reduction in serum phosphorus would lead to a decrease in proteinuria in these patients.

Hyperphosphatemia is associated with overt proteinuria in non-diabetic patients with late-stage chronic kidney disease: a cross-sectional study.

PURPOSE: Proteinuria plays an important role in the progression of chronic kidney disease (CKD), as well as a powerful predictor of cardiovascular morbidity and mortality. The aim of our study was to investigate the potential determinants associated with overt proteinuria in non-diabetic patients with late-stage CKD. METHODS: Between January 2006 and September 2011, a total of 418 non-diabetic patients with CKD stage 3-5 were enrolled from the outpatient department of nephrology. Urinary protein-to-creatinine ratio and serum phosphorus were determined. Other laboratory parameters, associated comorbidities, medication use, body mass index, and blood pressure were also assessed. RESULTS: The mean age of the patients was 66.7 ± 14.0 years. In multiple logistic regression analysis and adjusting for established risk factors, the odds ratios for overt proteinuria were 3.96 (95 % confidence interval, 1.80-8.76; p = 0.001) for higher serum phosphorus level (≥4.3 mg/dl) and 3.56 (95 % confidence interval, 1.47-8.63; p = 0.005) for hypercholesterolemia (≥217 mg/dl), compared to subjects with serum phosphorus <3.3 mg/dl and cholesterol level 158-184 mg/dl. The similar significant findings remained robust in individuals not receiving phosphate binder. CONCLUSIONS: Hyperphosphatemia and high serum cholesterol are associated with overt proteinuria in non-diabetic patients with late-stage CKD. Further studies should clarify whether this relation is causal and whether serum phosphorus level should be a new therapeutic target for proteinuria reduction.

Prevalence of hyperuricemia and its association with antihypertensive treatment in hypertensive patients in Taiwan.

BACKGROUND: Hyperuricemia is thought to be associated with an increased risk of hypertension, impaired renal function and cardiovascular disease. Our aim is to study the prevalence of hyperuricemia and its association with antihypertensive treatment in Taiwanese hypertensive subjects. METHODS: We recruited 2145 hypertensive subjects from 19 hospitals in four areas of Taiwan. We assessed the prevalence of hyperuricemia and determined the independent risk factors for raised serum uric acid level by multiple logistic regression analyses. RESULTS: Compared to the general population, hypertensive subjects in Taiwan had a higher prevalence (mean 35% in males, 43% in females) of hyperuricemia; this prevalence being 1.5- and 1.7-fold higher in males and females respectively. Uric acid levels; gout and prevalence of hyperuricemia were found to be highest in the younger age group (20-39 years) and no regional differences were noted. The most important risk factors for hyperuricemia were impaired renal function and diuretic use. Serum uric acid values correlated significantly with four quintiles of serum creatinine (p<0.0001) independent of diuretic use. Diuretic users had a significantly elevated serum uric acid and serum creatinine values than non-users. Among the patients given diuretics, hyperuricemia occurred in 44% of those given thiazides, in 56% of those given loop diuretics, and in 57% of those given aldosterone receptor blockers. CONCLUSIONS: Diuretic usage and renal function status have a strong impact on the prevalence of hyperuricemia in Taiwanese hypertensive subjects. It is still unclear, however, whether diuretics induce renal failure through elevating serum uric acid levels.

Endovascular revascularization of chronically thrombosed arteriovenous fistulas and grafts for hemodialysis: a retrospective study in 15 patients with 18 access sites.

The current study retrospectively evaluated whether endovascular revascularization of chronically thrombosed and long-discarded vascular access sites for hemodialysis was feasible. Technical and clinical success rates, postintervention primary and secondary patency rates, and complications were reported. During a 1-year period, we reviewed a total of 924 interventions performed for dysfunction and/or failed hemodialysis vascular access sites and permanent catheters in 881 patients. In patients whose vascular access-site problems were considered untreatable or were considered treatable with a high risk of failure and access-site abandonment, we attempted to revascularize (resurrect) the chronically occluded and long-discarded (mummy) vascular access sites. We attempted to resurrect a total of 18 mummy access sites (mean age 46.6 ± 38.7 months; range 5-144) in 15 patients (8 women and 7 men; mean age 66.2 ± 11.5 years; age range 50-85) and had an overall technical success rate of 77.8%. Resurrection failure occurred in 3 fistulas and in 1 straight graft. The clinical success rate was 100% at 2 months after resurrection. In the 14 resurrected vascular access sites, 6 balloon-assisted maturation procedures were required in 5 fistulas; after access-site maturation, a total of 22 interventions were performed to maintain access-site patency. The mean go-through time for successful resurrection procedures was 146.6 ± 34.3 min (range 74-193). Postmaturation primary patency rates were 71.4 ± 12.1% at 30 days, 57.1 ± 13.2% at 60 days, 28.6 ± 13.4% at 90 days, and 19 ± 11.8% at 180 days. Postmaturation secondary patency rates were 100% at 30, 60, and 90 days and 81.8 ± 11.6% at 180 days. There were 2 major complications consisting of massive venous ruptures in 2 mummy access sites during balloon dilation; in both cases, prolonged balloon inflation failed to achieve hemostasis, but percutaneous N-butyl cyanoacrylate glue seal-off was performed successfully. Percutaneous resurrection of mummy vascular access sites for hemodialysis is technically feasible with high clinical success rates. In selected patients, resurrection of mummy access sites provides long-discarded access sites one more chance to be used for hemodialysis in an effort to preserve potential extremity sites for future access-site placement and to prevent long-term catheter indwelling.

Endovascular treatment of autogenous radiocephalic fistulas with the "eighth note" deformity for hemodialysis.

The purpose of this paper is to describe a unique "eighth note" deformity of the autogenous radiocephalic fistula for hemodialysis and to retrospectively evaluate the efficacy and safety of its endovascular treatment. Over 3 years, a total of 808 patients and 558 autogenous radiocephalic fistulas were treated for vascular access dysfunction or thrombosis. These included 14 fistulas in 14 patients (9 men, 5 women; mean age, 58.2 +/- 2.8 years; range 27-79 years) whose fistulograms before treatment resembled a musical note, the eighth note. Endovascular treatment sought to remodel the deformed vascular access to a classic radiocephalic fistula and increase the number of cannulation sites available for hemodialysis. The technical and clinical success rates were each 92.8% (13/14). Fistula remodeling was successful in 13 patients. The postintervention primary patency was 100% at 90 days, 91.7 +/- 0.8% at 120 days, 78.6 +/- 13.9% at 180 days, 62.9 +/- 17.9% at 360 days, 31.4 +/- 24.0% at 540 days, and 0% at 720 days. The postintervention secondary patency was 100% at 90 days, 100% at 120 days, 100% at 180 days, 85.7 +/- 13.2% at 360 days, and 85.7 +/- 13.2% at 720 days. No major complications were noted. Minor complications were found in 71.4% of patients, all of which resolved spontaneously. In conclusion, endovascular treatment of fistulas with the eighth note deformity can effectively increase the number of available cannulation sites, facilitate fistula maturation, and facilitate thromboaspiration after fistula thrombosis.