Vascular Access Blood Flow Research Articles

Progressive increase in vascular access blood flow after percutaneous transluminal angioplasty in patients on hemodialysis.

Percutaneous transluminal angioplasty (PTA) is the gold standard for treating stenoses with dysfunctional vascular access. Recently, we found that vascular access blood flow (VABF) measured immediately after PTA increased over time without the need for additional procedures in the patients who underwent PTA. Therefore, this study was conducted to confirm an increase in VABF after PTA and identify the factors associated with it. Patients on chronic hemodialysis at a single institution were retrospectively reviewed and those with accesses that had a measurement of VABF immediately after PTA and within 1 month from PTA were included in the study. The relationship between clinical parameters and changes in VABF were analyzed using paired t-test and linear regression. A total of 47 PTA accesses (fistulas, 26; grafts,21) were included. The mean VABF on the day of PTA and the following measurement were 796.9 ± 329.1 mL/min and 1105.1 ± 410.3 mL/min, respectively. In the univariate analysis, the diameter of the balloon catheter used in the PTA and serum uric acid (SUA) level were significantly associated with an increase in VABF. Atrial fibrillation was a significant factor for the percentage change in vascular access. In the multivariate analysis, SUA level, balloon catheter diameter, and atrial fibrillation remained independent factors for changes in VABF and percentage change in VABF, respectively. The study identified progressive increases in the VABF after PTA without additional procedures. SUA level, balloon catheter diameter used in PTA, and atrial fibrillation were independently associated with changes in VABF.

Systemic vascular resistance predicts high-output cardiac failure in patients with high-flow arteriovenous fistula.

Patients with high-flow arteriovenous (AV) access are at risk of developing high-output cardiac failure (HOCF) and subsequent hospitalization. However, diagnosing HOCF is challenging and often requires invasive procedures. The role of systemic vascular resistance (SVR) in diagnosing HOCF is underestimated, and its predictive value is limited. Our study aims to identify non-invasive risk factors for HOCF to facilitate early diagnosis and timely surgical interventions. We included 109 patients with high-flow AV access who underwent serial echocardiography. The retrospective cohort was divided into two groups based on their hospitalization due to HOCF. The two groups were matched for age and gender. After a mean follow-up of 25.1months, 19 patients (17.4%) were hospitalized due to HOCF. The two groups had similar baseline characteristics. However, the HOCF group had a higher value of vascular access blood flow (Qa) (2168±856 vs. 1828±617mL/min; P=0.045). Echocardiographic analysis revealed that the HOCF group had more pronounced left ventricular diastolic dysfunction (E/e': 21.1±7.3 vs. 16.2±5.9; P=0.002), more severe pulmonary hypertension (right ventricular systolic pressure: 41.4±16.7 vs. 32.2±12.8; P=0.009), a higher Doppler-derived cardiac index (CI) (4.3±0.8 vs. 3.7±1.1; P=0.031), and a lower Doppler-derived estimated SVR (eSVR) value (5.5±0.3 vs. 6.9±0.2; P=0.002) than the non-HOCF group. Using multivariable Cox regression analysis, a low eSVR value (<6) emerged as an independent predictor of HOCF hospitalization with a hazard ratio of 9.084 (95% confidence interval, 2.33-35.39; P=0.001). Receiver operating characteristic curve analysis indicated that CI/eSVR values more accurately predicted HOCF hospitalization [sensitivity: 94.7%, specificity: 51.0%, area under the curve (AUC): 0.75, P<0.001] than the Qa/cardiac output ratio (AUC: 0.50, P=0.955), Qa values≥2000mL/min (AUC: 0.60, P=0.181), and Qa values indexed for height in metres (AUC: 0.65, P=0.040). In patients with high-flow AV access, low eSVR values obtained through non-invasive Doppler echocardiography were associated with a high rate of HOCF hospitalizations. Therefore, routine eSVR screening in these patients might expedite the diagnosis of HOCF.

MO771: Haemodialysis Access Flow Measurement: Comparison of Ultrasound Dilution and Ultrafiltration Method on Nikisso DBB-EXA™ Dialysis Machine

Abstract BACKGROUND AND AIMS The regular measurement of the haemodialysis vascular access (VA) flow demonstrates a protective effect over thrombotic complications [1]. Transonic® Ultrasound dilution technique was first introduced in 1995 and progressively became a method of reference for recirculation and blood flow measurement on haemodialysis VA [2]. It is based on the technique of haemodilution with a certain volume of 0.9% NaCl and the measure of recirculation with inversed lines using the ultrasound technique. Consecutively the VA flow is estimated with a certain formula. Nikisso DBB-EXA™ dialysis machine has the capacity to measure the VA recirculation rate by photometry performing a controlled rise on ultrafiltration rate. The aim of the present study is to compare the VA flow rate between the Transonic® Ultrasound dilution technique and the Nikisso DBB-EXA™ Ultrafiltration method. METHOD The primary outcome of the study is the association of VA flow measured by Transonic® and the Nikisso DBB-EXA™. During the first half of the same dialysis session, we measured the VA recirculation and flow rate twice with the two methods under a constant dialysis blood pump flow of 250–300 mL/min with the ultrafiltration and haemodiafiltration interrupted during the procedure after having reversed the dialysis lines. RESULTS The values are represented as mean ± SD. A total of 18 chronic haemodialysis patients (13 male: 5 female, mean age: 70 ± 14 years) participated in the study. They were haemodynamically stable without acute clinical conditions and were dialysed with a well-functioning arteriovenous fistula for at least 6 months. The mean value of recirculation with inverted dialysis lines for the Transonic® method was 20.79 ± 7.58% and for the Nikisso DBB-EXA™ was 24.43 ± 7.77. The mean values of VA blood flow with the Transonic® method were 1229 ± 588 mL/min and for the Nikisso DBB-EXA™ 1096 ± 490 mL/min. The measured values of the two methods presented a significant positive correlation (by Pearson) (R = 0.920, P &amp;lt; 0.001) (Figure). CONCLUSION There is a significantly positive correlation concerning the VA flow measurement between the reference method of Transonic® and the Ultrafiltration method offered by the Nikisso DBB-EXA™. Larger studies are needed to confirm this correlation with an additional comparative analysis of the reproducibility of measurements.

Study of Anti-C1q Antibodies in Egyptian Systemic Lupus Erythematosus Patients.

Autoantibodies to complement are associated with various diseases. Anti-C1q antibodies are present in all patients with hypocomplementemic urticarial vasculitis, but also with varying prevalence in other conditions. Anti-C1q may interfere with the clearance of apoptotic cells, so influencing induction and expression of autoimmunity. The aim of this work is to study the relation between anti-C1q antibodies and systemic lupus erythematosus (SLE) and its manifestations including renal affection. The presence and levels of anti-C1q antibodies were investigated using enzyme-linked immunosorbent assay technique. The study included 70 Egyptian patients suffering from SLE and 18 healthy controls. They were 65 females and five males. Their age ranged from 12 to 48.5 years with a mean value of 27.4 ± 8.4. Anti-C1q antibodies were statistically significantly elevated in cases compared with controls being positive in 37.2% (mean 18.3 ± 27.1) in patients versus 11.1% (mean value 4.1 ± 3.5) in controls (P = 0. 03). Anti-C1q antibody-positive patients (n = 226) had significantly higher SLE Disease Activity Index (SLEDAI) (16.1 ± 9.9) compared to negative patients (n = 44) (SLEDAI = 8.1 ± 7.7) P = 0.000. Regarding renal affection, the presence of anti-C1q-positive antibodies was associated with proteinuria, P = 0.002. In conclusion, anti-C1q was more common in patients with SLE and disease activity. We confirmed a significant association of anti-C1q with renal involvement, independent of demographics and other serologies.

Correlation of Serum Vitamin D Levels to Vascular Access Dysfunction in Prevalent Hemodialysis

Abstract Vascular access dysfunction in hemodialysis patients has been correlated to low serum vitamin D level in previous studies. Vitamin D deficiency and hepatitis C virus infection have been linked to endothelial cell dysfunction, promoting inflammatory cascade.30 negative - &amp; 30 positive - hepatitis C virus patients on prevalent hemodialysis in Ain Shams University Hospitals, were enrolled in the study. All patients had access blood flow &amp;lt; 800 ml/min. For all patients we performed: complete physical examination, complete blood count, serum ferritin, ESR 1st and 2nd hours, CRP, blood urea, serum creatinine, serum albumin, total and direct bilirubin, alanine transferase, aspartate transferase, prothrombin time, International Normalized Ratio, serum calcium and phosphorus, and serum intact parathyroid hormone. Previous laboratory tests were performed using conventional methods within our hospitals laboratories. Serum vitamin Dlevel was measured by Enzyme Linked Immunosorbent Assay. Access blood flow was measured by Duplex Ultrasound. Vitamin D serum level was &amp;lt; 20 ng/ml within negative and positive groups with no significant difference between them. Vascular access flow was significantly lower within positive patients. Parathyroid hormone, Phosphorus, Prothrombin time, International Normalized Ratio, Alanine - and Aspartate - transferase were significantly higher within positive patients. We deduced that Vitamin D level &amp;lt; 20ng/ml was associated with reduced vascular access blood flow &amp;lt; 800 ml/min, with much more reduced access flow within hepatitis C virus positive patients. [Mona Hosny Abdel Salam, Reem Jan Farid, Mostafa Abdelnassier Abdelgawad and Marwa Salim Youssef Ismail. Correlation of Serum Vitamin D Levels to Vascular Access Dysfunction in Prevalent Hemodialysis.

Vascular Access Perspectives in Patients After Kidney Transplantation.

Introduction: More attention has been paid to the influence of arteriovenous fistula (AVF) on the cardiovascular system. In renal transplant recipients, some beneficial effect of an elective vascular access (VA) ligation was observed in patients with a high AVF flow. However, this strategy is not widely accepted and is in contradiction to the rule of vasculature preservation for possible future access. The aim of our study is to elucidate the vascular access function and VA perspective in the kidney transplantation (KTx) population.Materials and Methods: KTx patients with a stable graft function were recruited to participate in this single center observational study (NCT04478968). The measurement of VA flow and vessel mapping for future vascular access was performed by a color Doppler ultrasound. The study group included 99 (63%) males and 58 (37%) females; the median age was 57 (IQR 48–64) years. The median time from the transplantation to the baseline visit was 94 (IQR 61–149) months. Median serum creatinine concentration was 1.36 (IQR 1.13–1.67) mg/dl.Results: Functioning VA was found in 83 out of 157 (52.9%) patients. The sites were as follows: snuffbox in six (7.2%), wrist in 41 (49.4%), distal forearm in 18 (21.7%), middle or proximal forearm in eight (9.6%), upper-arm AV graft in one (1.2%), and upper-arm AVFs in nine (10.8%) patients, respectively. Blood flow ranged from 248 to 7,830 ml/min; the median was 1,134 ml/min. From the transplantation to the study visit, 66 (44.6%) patients experienced access loss. Spontaneous thrombosis was the most common, and it occurred in 60 (90.9%) patients. The surgical closure of VA was performed only in six (4%) patients of the study group with a functioning VA at the time of transplantation. Access loss occurred within the 1st year after KTx in 33 (50%) patients. Majority (50 out of 83, 60.2%) of the patients with an active VA had options to create a snuffbox or wrist AVF on the contralateral extremity. In a group of 74 patients without a functioning VA, the creation of a snuffbox or wrist AVF on the non-dominant and dominant extremity was possible in seven (9.2%) and 40 (52.6%) patients, respectively. In 10 (13.1%) patients, the possibilities were limited only to the upper-arm or proximal forearm VA on both sides. Access ligation was considered by 15 out of 83 (18.1%) patients with a patent VA.Conclusions: In the majority of the patients, vascular access blood flow was below the threshold of the negative cardiovascular effect of vascular access. Creation of a distal AVF is a protective measure to avoid a high flow and preserve the vessels for future access. The approach to VA should be individualized and adjusted to the patient's profile.

Effects of hemodialysis access surveillance on reducing risk of hemodialysis access thrombosis: A meta-analysis of randomized studies.

Vascular access thrombosis remains the Achilles Heel for many a hemodialysis patient. We performed a systematic review and meta-analysis to assess the impact of monitoring vascular access blood flow on prediction and prevention of vascular access thrombosis. We hypothesized that monitoring vascular access blood flow has a pivotal role in lowering the risk of thrombosis and subsequent access failure. We conducted a systematic review in PubMed and EMBASE databases to identify randomized studies that have assessed the effect of hemodialysis access surveillance on the risk of thrombosis. A random-effects model was used for the meta-analysis. Subgroup analysis was performed among patients with arterio-venous fistula (AV-fistulas) and those with arterio-venous graft (AV-grafts). Ten randomized studies were included in the meta-analysis. The total number of patients included in the analysis was 1430. On performing the random-effects model among the included studies, hemodialysis access surveillance was associated with better outcomes (risk ratio = 0.73, 95% confidence interval ranges from 0.55 to 0.98). The analysis of the AV-fistula group showed an estimated overall risk ratio of 0.55 (95% confidence interval ranges from 0.33 to 0.89) favoring access surveillance. However, in the AV-grafts group, the estimated overall risk ratio was 0.92 (95% confidence interval ranges from 0.65 to 1.29) showing no additional benefit for access surveillance. Hemodialysis access surveillance using access blood flow monitoring can reduce the risk of access thrombosis for patients with AV-fistulas, but this is not the case with AV-grafts.

Changes in vascular access blood flow: Etiological factors and clinical implications.

Records of 10,000 QVA measurement performed in 549 patients over 20 years were used as retrospective and anonymized data source, making ethical commission involvement unnecessary. Two approaches are used to elucidate association of QVA changes with different factors: analyses of smaller cohorts in which both the QVA and the respective factor were measured (e.g. association of QVA with cardiac output (CO)), or-in case of rare phenomena-a form of a well illustrated case reports was used (e.g. association of QVA and Kt/V). Significant increase in CO after permanent VA creation (3-4-fold of the QVA value) was found. Impact of intradialytic CO changes on QVA is attenuated by relatively stable VA resistance compared to systemic resistance. Blood pressure impact is much stronger and it should therefore be noted at each QVA measurement. As reproducibility of different QVA measurement methods varies, use of the same method should be preferred. Direction of the arterial needle insertion in VA affects the QVA measured, especially in synthetic grafts, too. Also patient's own QVA variability may be quite high. All this makes KDOQI/EBPG recommended acceptable QVA drops too strict, they should be revised. In re-stenoses prone patients, measurement intervals should be shortened, too. QVA values are significantly affected by many factors. Their knowledge appears essential for safe and effective VA surveillance and management.

Stima della portata della fistola artero-venosa mediante termodiluizione nei pazienti in emodialisi cronica: esperienza monocentrica.

Purpose: Vascular access surveillance in hemodialysis is today an important challenge for nephrologist. Low blood flow is a risk factor for development of thrombosis of native fistula or graft.&#x0D; The aim of the study is to evaluate the correspondence between flow measurement by thermodilution and Color Doppler, and to identify flow rate values using the Blood temperature monitor (BTM) method in the case of stenosis.&#x0D; Methods: We evaluated 29 patients on chronic hemodialysis. The evaluation of blood flow with BTM were performed during the first hour of the hemodialysis session. All patients underwent a color doppler of vascular access within 10 days from the BTM measurements.&#x0D; Results: The mean vascular access flow calculated with BTM resulted 1142 ± 700 ml/min and there was a correlation with color doppler data 1199 ± 644 ml/min (p=0,0001 r=0,829). The flow of patients with hemodynamically significant stenosis was 332 ± 92 ml/min with a minimum value of 270 ml/min and a maximum value of 440 ml/min.&#x0D; Conclusion: the correspondence between thermodilution and color doppler support the implementation of intradialitic evaluation of the vascular access blood flow with the BTM method. Thermodilution allows to identify earlier patients with high risk of vascular access failure and the need for further diagnostic and therapeutic investigations.

High-flow arteriovenous fistula and heart failure: could the indexation of blood flow rate and echocardiography have a role in the identification of patients at higher risk?

Although only high-flow arteriovenous fistulas (AVFs) are postulated to cause high-output cardiac failure (HOCF), there are currently no universally accepted criteria defining a high-flow fistula. To verify if vascular access blood flow (Qa) ≥ 2000ml/min provides an accurate definition of high-flow fistula, we selected 29 consecutive patients with Qa ≥ 2000ml/min at color-duplex ultrasound examination and assessed them for the presence of cardiac failure symptoms; transthoracic echocardiography was also performed. Nineteen patients (65%) had heart failure symptoms and were classified with HOCF. At receiver operating characteristic (ROC) curve analysis, Qa ml/min values did not identify patients with heart failure symptoms but when AVF blood flow was indexed for height2.7, Qa ≥ 603ml/min/m2.7 detected the occurrence of HOCF with good accuracy (sensitivity 100%, specificity 60%, efficiency 86%, positive predictive value 83%, negative predictive value 100%, area under curve 0.75). At echocardiographic evaluation, patients with Qa ≥ 603ml/min/m2.7 had a more severe increase of left ventricular mass (63 ± 18 vs. 47 ± 7g/m2.7, p < 0.003), left ventricular diastolic volume (140 ± 42 vs. 109 ± 14ml, p < 0.007), left atrial volume (53 ± 23 vs. 39 ± 5ml/m2, p < 0.015), a higher incidence of diastolic dysfunction (70 vs. 17%, p < 0.019) and higher CO reduction after AVF manual compression (2151 ± 875 vs. 1292 ± 527ml/min, p < 0.009) than patients with Qa < 603ml/min/m2.7. Indexation of AVF blood flow should be considered in defining high-flow fistula because the effect of Qa may differ in individuals of different sizes. A Qa value ≥ 603ml/min/m2.7 and its association with some echocardiographic alterations could identify patients at higher risk for HOCF.

Adding access blood flow surveillance reduces thrombosis and improves arteriovenous fistula patency: a randomized controlled trial.

Stenosis is the main cause of arteriovenous fistula (AVF) failure. It is still unclear whether surveillance based on vascular access blood flow (QA) enhances AVF function and longevity. We conducted a three-year follow-up randomized, controlled, multicenter, open-label trial to compare QA-based surveillance and pre-emptive repair of subclinical stenosis with standard monitoring/surveillance techniques in prevalent mature AVFs. AVFs were randomized to either the control group (surveillance based on classic alarm criteria; n = 104) or to the QA group (QA measured quarterly using Doppler ultrasound [M-Turbo®] and ultrasound dilution [Transonic®] added to classic surveillance; n = 103).The criteria for intervention in the QA group were: 25% reduction in QA, QA<500 mL/min or significant stenosis with hemodynamic repercussion (peak systolic velocity [PSV] more than 400 cm/sc or PSV pre-stenosis/stenosis higher than 3). At the end of follow-up we observed a significant reduction in the thrombosis rate in the QA group (0.025 thrombosis/patient/year in the QA group vs. 0.086 thrombosis/patient/year in the control group [p = 0.007]). There was a significant improvement in the thrombosis-free patency rate (HR, 0.30; 95% CI, 0.11-0.82; p = 0.011) and in the secondary patency rate in the QA group (HR, 0.49; 95% CI, 0.26-0.93; p = 0.030), with no differences in the primary patency rate between the groups (HR, 0.98; 95% CI, 0.57-1.61; p = 0.935).There was greater need for a central venous catheter and more hospitalizations associated with vascular access in the control group (p = 0.034/p = 0.029).Total vascular access-related costs were higher in the control group (€227.194 vs. €133.807; p = 0.029). QA-based surveillance combining Doppler ultrasound and ultrasound dilution reduces the frequency of thrombosis, is cost effective, and improves thrombosis free and secondary patency in autologous AVF.

Effects of far infrared therapy on arteriovenous fistulas in hemodialysis patients: a meta-analysis

Background: Far infrared (FIR) therapy may have a beneficial effect on maturity and function of arteriovenous fistulas (AVFs) in hemodialysis (HD) patients. Therefore, we performed this pooled analysis to assess the protective effects of FIR therapy in HD patients.Methods: The randomized controlled trials (RCTs) and quasi-RCTs of FIR therapy for HD patients were searched from multiple databases. Relevant studies were screened according to the predefined inclusion criteria. The meta-analyses were performed using RevMan 5.2 software (The Cochrane Collaboration, Oxford, UK).Results: Meta-analysis showed that FIR therapy could significantly increase the vascular access blood flow level (MD, 81.69 ml/min; 95% CI, 46.17–117.21; p < .001), AVFs diameter level (MD, 0.36 mm; 95% CI, 0.22–0.51; p < .001), and the primary AVFs patency (pooled risk ratio = 1.24; 95% CI, 1.12–1.37, p < .001). In addition, therapy with FIR ray radiation could decrease AVFs occlusion rates (pooled risk ratio = 0.20; 95% CI, 0.08–0.46; p < .001) and the level of needling pain (pooled risk ratio = 0.08; 95% CI, 0.06–0.10, p < .001).Conclusions: FIR therapy can reduce AVFs occlusion rates and needling pain level, while significantly improve the level of vascular access blood flow, AVFs diameter and the primary AVFs patency.

Clinical utility of far-infrared therapy for improvement of vascular access blood flow and pain control in hemodialysis patients

BackgroundMaintenance of a well-functioning vascular access and minimal needling pain are important goals for achieving adequate dialysis and improving the quality of life in hemodialysis (HD) patients. Far-infrared (FIR) therapy may improve endothelial function and increase access blood flow (Qa) and patency in HD patients. The aim of this study was to evaluate effects of FIR therapy on Qa and patency, and needling pain in HD patients. MethodsThis prospective clinical trial enrolled 25 outpatients who maintained HD with arteriovenous fistula. The other 25 patients were matched as control with age, sex, and diabetes. FIR therapy was administered for 40 minutes during HD 3 times/wk and continued for 12 months. The Qa was measured by the ultrasound dilution method, whereas pain was measured by a numeric rating scale at baseline, then once per month. ResultsOne patient was transferred to another facility, and 7 patients stopped FIR therapy because of an increased body temperature and discomfort. FIR therapy improved the needling pain score from 4 to 2 after 1 year. FIR therapy increased the Qa by 3 months and maintained this change until 1 year, whereas control patients showed the decrease in Qa. The 1-year unassisted patency with FIR therapy was not significantly different from control. ConclusionFIR therapy improved needling pain. Although FIR therapy improved Qa, the unassisted patency was not different compared with the control. A larger and multicenter study is needed to evaluate the effect of FIR therapy.

The Rise and Fall of Access Blood Flow Surveillance in Arteriovenous Fistulas

Vascular access blood flow (Qa) surveillance has been described as a typical false paradigm, an example of how new tests are sometimes adopted even without good-quality evidence of their benefits. This may be true for grafts, but not necessarily for arteriovenous fistulas. We reviewed the literature on Qa surveillance in fistulas to see whether it complies with the World Health Organization's criteria for screening tests. Measuring Qa has a fairly good reproducibility. Qa shows an excellent-to-good accuracy for stenosis being the only bedside screening test that achieves a very high sensitivity while retaining a fair-to-good positive predictive value for Qa thresholds of 600ml/minute or higher associated with a >25% drop in Qa, or findings suggesting stenosis on physical examination. The accuracy of Qa in predicting thrombosis is hard to establish because of the heterogeneity of published studies, though a Qa of 300ml/minute seems the most reliable cutoff. Qa surveillance affords a significant 2- to 3-fold reduction in the risk of thrombosis by comparison with clinical monitoring alone when Qa criteria highly sensitive to stenosis are considered, regardless of the study design (randomized controlled trials, cohort studies with concurrent or historic controls). Using highly sensitive Qa screening criteria also halves the risk of access loss, although this effect is not statistically significant. Our analysis strongly suggests that Qa surveillance is an effective method for screening mature fistulas, though further, appropriately designed studies are needed to fully elucidate its benefits and cost effectiveness.

Predicting dialysis vascular access blood flow and diameter: too much, too little, or just right

Arteriovenous fistula (AVF) maturation continues to cause significant morbidity and mortality. Despite the magnitude of the clinical problem, however, there are no effective clinical or biological predictors of AVF success or failure. Caroli et al. describe an innovative technology that may be successful in predicting AVF flow and diameter using standard-of-care preoperative inputs. Pending additional longer-term validation, the use of this technology could help us get the right access into the right patient at the right time.

Clinical effects of buttonhole cannulation method on hemodialysis patients

Although the buttonhole cannulation method is now widely used as an alternative to the rope-ladder method in most countries, only the latter method is used in Korea. This study was performed to investigate clinical benefit of the buttonhole technique for arteriovenous fistula (AVF) cannulation in maintenance hemodialysis (HD) patients. Thirty-two patients receiving HD via mature AVF were included and AVF cannulation was performed by 20 experienced nurses. During the 8 weeks, AVFs were cannulated by the rope-ladder method with 15-gauge sharp needles. After creating of 2 pairs of tunnel tracks by sharp needles for 7 weeks, AVFs were cannulated by the buttonhole method using 15-gauge blunt needles during the 16 weeks. Vascular access blood flow rate (BFR), dialysis venous pressure (DVP), and dialysis adequacy (Kt/V) were measured within the first week of the two cannulation methods. Cannulation pain, hemostasis time, and nurse's stress were evaluated at the end of the two methods. There were no statistical differences in vascular access BFR (P = 0.139), DVP (P = 0.152), and dialysis adequacy (P = 0.343) between the two methods. However, the buttonhole method shortened hemostasis time (P = 0.001) and decreased cannulation pain (P = 0.001) as well as nurse's stress (P = 0.001) compared with the rope-ladder method. In conclusion, the buttonhole cannulation method improves hemostasis time, cannulation pain, and nurse's stress without a change in vascular access BFR and dialysis adequacy in HD patients.

Thermodilution versus saline dilution method for vascular access blood flow measurement in high-flux and on-line hemodiafiltration

Access blood flow (Qa) measurements are one of the most important components in vascular access monitoring programs, even though these indirect methods have only been validated with high-flux hemodialysis (HF; pump flow [Qb] 300 mL/min). This study was to assess the utility from thermodilution (BTM) with respect to the saline dilution method (SDM) in HF and on-line hemodiafiltration (OL-HDF) with routinely prescribed parameters in comparison with validation conditions. Three consecutive sessions were assessed in 31 hemodialysis patients (27AVF). The Bland-Altman method and Lin's concordance coefficient (ρc) were used to study accuracy and precision. We used the student t test for the analysis of Qa-value in the different subgroups. In HF-hemodialysis 1 (Qb 300 mL/min), Qa was 1109 ± 541 mL/min SDM(a) and 1213 ± 639 mL/min BTM (P=.993(a); bias 103.7 mL/min and ρc 0.78). In HF-hemodialysis 2 (Qb 420 mL/min) Qa 1071 ± 578 mL/min SDM (P=1.0(a); -38.2 mL/min and 0.96) and 1216 ± 667 mL/min BTM (P=.992(a); 127.3 mL/min and 0.70). In OL-HDF hemodialysis 3 (Qb 420 mL/min) Qa 1071 ± 510 mL/min SDM (P=1.0(a); -48.4 mL/min and 0.96) and 1219 ± 580 mL/min BTM (P=.977(a); 99.2 mL/min and 0.75). Statistically significant differences were only obtained in patients aged ≥ 65 years old (P=.016) and peripheral vascular disease (P=.007). Our results demonstrate how the saline dilution method was more accurate than thermodilution in the HF and OL-HDF modalities with routinely prescribed parameters. Finally, in this study, advanced age (>65 years old) and peripheral vascular disease were associated with a significantly lower Qa-value.

Home hemodialysis: Present state of the evidence

disappointing results suggested that the high mortality associated with hemodialysis could not be impacted upon with relatively small increases in solute clearance. It also further questioned the rationale of focusing on Kt/V as a measure of dialysis adequacy. The mortality rate for hemodialysis patients in the U.S. is high at approximately 24.4 deaths/100 patient-years.4 The high mortality rate has persisted despite progressive increases in Kt/V over the past two decades, from 1.11 in 1991 to 1.52 in 2002.5 In addition, despite this increase in Kt/V, the complications of hypertension,6 malnutrition,7 congestive heart failure,8 and bone and mineral disorders9 have remained unacceptably high. These outcome data clearly indicate that dialysis adequacy cannot be simply measured in terms of Kt/V. Given these persistently poor outcomes

Arteriovenous Fistula, Blood Flow, Cardiac Output, and Left Ventricle Load in Hemodialysis Patients

The aim of this study was to investigate an association between vascular access blood flow (QVA), cardiac output(CO), and load of left ventricle (LLV) using a simple physical model calculation based on real data, specifically inpatients with high access blood flow arteriovenous fistula(AVF). Vascular access blood flow, CO, and peripheral vascular resistance (PR) were determined by ultrasound dilution technique (HD01; Transonic Systems, Inc., Ithaca, NY). Load of left ventricle was calculated using simplified formula: LLV x PR CO2. This total load was computationally divided into the part spent to run the flow QVA through the AVF (LLVAVF) and that part ensuring the flow (CO-QVA) through the vascular system. The model calculation was first performed in a selected group of 15 patients with high access blood flow (QVA >1,300 ml/min, group 1) and later extended for comparison by another group of 40 unselected patients with access blood flow in lower range (QVA range 200-1,400 ml/min, group 2).Mean LLV in group 1 was 2.10 +/- 0.68 W. LLV(AVF) was 21.8% of total LLV. Mean LLV in group 2 was 1.2 +/- 0.5 W.LLVAVF was 11.1% of total LLV. Our computational results suggest that AVF in typical range of QVA shall not increase heart load significantly.

Early Vascular Access Blood Flow as a Predictor of Long-term Vascular Access Patency in Incident Hemodialysis Patients

The long-term clinical benefits of vascular access blood flow (VABF) measurements in hemodialysis (HD) patients have been controversial. We evaluated whether early VABF may predict long-term vascular access (VA) patency in incident HD patients. We enrolled 57 patients, of whom 27 were starting HD with arteriovenous fistulas (AVFs) and 30 with arteriovenous grafts (AVGs). The patients' VABF was measured monthly with the ultrasound dilution technique over the course of the first six months after the VA operation. During the 20.4-month observational period, a total of 40 VA events in 23 patients were documented. The new VA events included 13 cases of stenosis and 10 thrombotic events. The lowest quartile of average early VABF was related to the new VA events. After adjusting for covariates such as gender, age, hypertension, diabetes, VA type, hemoglobin levels, body mass index, parathyroid hormone, and calcium-phosphorus product levels, the hazard ratio of VABF (defined as <853 mL/min in AVF or <830 mL/min in AVG) to incident VA was 3.077 (95% confidence interval, 1.127-8.395; P=0.028). There were no significant relationships between early VABF parameters and VA thrombosis. It is concluded that early VABF may predict long-term VA patency, particularly VA stenosis.