Increased Blood Flow Rate Research Articles

Experimental study on two-way application of traditional Chinese medicines capable of promoting blood circulation and removing blood stasis with neutral property in cold and hot blood stasis syndrome I

To study the action characteristics of "two-way application and conditioned dominance" of traditional Chinese medicines with neutral property by observing the action characteristic of 10 traditional Chinese medicines capable of promoting blood circulation and removing blood stasis with neutral property in the microcirculation in rats with heat stagnation and blood stasis syndrome. The rat model with heat stagnation and blood stasis syndrome was established by injecting carrageenan and dry yeast, and the rat model with cold stagnation and blood stasis syndrome was built by the body freezing method. Ten traditional Chinese medicines with neutral property, including 5 with hot property and 5 with cold property, were selected for intervention to observe blood flow rate and flow state indicators in rat auricles and make a comparative analysis on action characteristics of traditional Chinese medicines with neutral property. ANOVA showed that among the 10 traditional Chinese medicines with neutral property, 6 such as Typhae Pollen, Sappan Lignum and Vaccariae Semen can obviously increase the blood flow rate (P < 0.01 or P < 0.05) in the above two models; all of the 5 traditional Chinese medicines with cold property can increase the blood flow rate (P < 0.01 or P < 0.05) in the rat model with heat stagnation and blood stasis syndrome, but only Salvia miltiorrhiza can increase the blood flow rate (P < 0.01 or P < 0.05) in the rat models with cold stagnation and blood stasis syndrome, while other medicines showed no notable effect; among the 5 traditional Chinese medicines with hot property, Carthamus tinctorius and Ligusticum chuanxiong can increase the blood flow rate (P < 0.01 or P < 0.05) in the rat models with cold stagnation and blood stasis syndrome, but had no obvious effect to the blood flow rate in the rat models with heat stagnation and blood stasis syndrome. According to the analysis on average blood flow rate, traditional Chinese medicines with natural and cold properties showed similar effect on heat stagnation and blood stasis syndrome and better effect in increasing blood flow rate than those with hot property; those with natural and hot properties showed similar effect and better effect in increasing blood flow rate than those with cold property. Under the condition of heat stagnation and blood stasis syndrome, traditional Chinese medicines with neutral property have the similar action characteristics with those with cold property; wile under the condition of cold stagnation and blood stasis syndrome, traditional Chinese medicines with neutral property have the similar action characteristics with the Chinese medicinal herbs with hot property. This indicates the action characteristics of "two-way application and conditioned dominance" of traditional Chinese medicines with neutral property to some extent.

Modalities of hemodialysis: quality improvement.

Hemodialysis (HD) treatment had, over many years, improved the survival rate of patients with end-stage renal disease. However, standard or conventional HD prescription is far from being optimal in replacing the function of normal kidneys. Its unphysiologic clearance pattern and inability to remove all types and sizes of uremic toxins results in inter- and intra-dialysis complications and an unacceptably high rate of cardiovascular morbidity and mortality. Efficiency of HD can be improved by increasing blood and dialysate flow rates, dialyzer size and surface area and duration and frequency of dialysis sessions. Home HD, where short daily or long slow nocturnal HD sessions can conveniently be performed, provides an excellent option for quality of life improvement and reduction in morbidity and mortality. Recent innovations in the specifications of HD machines and improvement in dialysis membranes characteristics and water treatment technology paved the way for achieving quality HD. These advancements have resulted in efficient implementation of adsorption, diffusion and/or convection principles using adsorption HD, hemofiltration, hemodiafiltration (HDF) and online HDF modalities in order to achieve optimum HD. Implementation of these innovations resulted in better quality care achievements in clinical practice and reduction in morbidity and mortality rates among HD patients.

The Prevalence of Metabolic Syndrome and Factors Associated with Quality of Dialysis among Hemodialysis Patients in Southern Taiwan

Objectives:The purpose of this study was to evaluate the prevalence of metabolic syndrome (MetS) among hemodialysis patients and factors associated with quality of dialysis.Methods:Data were collected from 377 long-term hemodialysis patients who received hemodialysis treatment from clinics in Tainan and Kaohsiung between November 2009 and February 2010. MetS was defined using criteria set by the adult treatment panel III (ATP-III). But, the cutpoint of waist circumference has been modified to adjust for Asian populations.The measurement of Kt/V was used as an indicator of the quality of dialysis. A below 1.4 Kt/V was considered poor dialysis quality.Results:Results showed that the prevalence of MetS among the chronic hemodialysis patients in this sample was 61.0%. Logistic regression results identified that the quality of dialysis in females was better than that in males (odds ratio (OR)=7.98, 95% confidence interval (CI): 2.52-25.31). Better quality dialysis was associated with older age, longer treatment time, and increased blood flow rate (OR=1.49, 13.63, and 1.35, respectively). However, for every one kilogram increase in weight, the quality of dialysis decreased by 13 percents (OR=0.87, 95% CI: 0.83-0.92).Conclusions:MetS is common among hemodialysis patients. The prevalence of hypertension, hyperlipidemia, and hyperglycaemia were significantly higher among hemodialysis patients. Quality of dialysis related to gender, age, weight, and the dialysis prescription (treatment time and blood flow rate).

Effect of handheld mobile phone use on parotid gland salivary flow rate and volume

Handheld mobile phones emit nonionizing electromagnetic radiations and generate heat during use which can be absorbed by the adjacent tissues. This study observed functional and volumetric changes in the parotid glands associated with mobile phone use. Unstimulated parotid salivary flow rate was measured bilaterally in 142 individuals divided into 2 groups of heavy users and control subjects using a modified Schirmer test. Bilateral parotid ultrasonography was performed to evaluate gland volume. Variation and correlation tests were used to statistically analyze the results. A significant increase in salivary flow rate along with increased blood flow rate and volume of the parotid glands of the side where mobile phones are frequently placed was observed in the heavy user group. Heavy users of mobile phones demonstrated increased salivary flow rate, blood flow rate, and volume of parotid glands.

Spinal Cord Blood Flow and Blood Vessel Permeability Measured by Dynamic Computed Tomography Imaging in Rats after Localized Delivery of Fibroblast Growth Factor

Following spinal cord injury, profound vascular changes lead to ischemia and hypoxia of spinal cord tissue. Since fibroblast growth factor 2 (FGF2) has angiogenic effects, its delivery to the injured spinal cord may attenuate the tissue damage associated with ischemia. To limit systemic mitogenic effects, FGF2 was delivered to the spinal cord via a gel of hyaluronan and methylcellulose (HAMC) injected into the intrathecal space, and compared to controls receiving HAMC alone and artificial cerebrospinal fluid (aCSF) alone. Dynamic perfusion computed tomography (CT) was employed for the first time in small animals to serially measure blood flow and permeability in the injured and uninjured spinal cord. Spinal cord blood flow (SCBF) and permeability-surface area (PS) measurements were obtained near the injury epicenter, and at two regions rostral to the epicenter in animals that received a 26-g clip compression injury. As predicted, SCBF measurements decreased and PS increased after injury. FGF2 delivered via HAMC after injury restored SCBF towards pre-injury values in all regions, and increased blood flow rates at 7 days post-injury compared to pre-injury measurements. PS was stabilized at regions rostral to the epicenter of injury when FGF2 was delivered with HAMC, with significantly lower values than aCSF controls at 7 days in the region farthest from the epicenter. Laminin staining for blood vessels showed a qualitative increase in vessel density after 7 days when FGF2 was locally delivered. Additionally, permeability stains showed that FGF2 moderately decreased permeability at 7 days post-injury. These data demonstrate that localized delivery of FGF2 improves spinal cord hemodynamics following injury, and that perfusion CT is an important technique to serially measure these parameters in small animal models of spinal cord injury.

A random method for theoretical estimation of RBC osmotic damage in removing CPAs from cryopreserved blood with hollow fiber modules: Closed-loop blood flow mode

A theoretical method is developed to study the effect of the closed-loop blood flow mode on the osmotic damage of red blood cells (RBCs) during the removal of permeable cryoprotective agents (CPAs) from cryopreserved blood with a hollow fiber module. In this method, RBC suspension/blood with CPAs is divided into finite units, which randomly enter the lumen side of hollow fibers by using a random program code; washing solution/dialysate without CPAs is divided into infinite units entering the shell side of hollow fibers continuously. Mass transfer across cell and fiber membranes is calculated by the unsteady-state model proposed in previous study. By this random method, the closed-loop blood flow mode is simulated. Then the effects of blood flow rates, dialysate flow rates, hydraulic permeabilities and solute permeabilities of hollow fibers on the osmotic damage of RBCs are estimated statistically and the washing efficiencies of CPAs are investigated theoretically. The results show that in order to reduce the osmotic damage of RBCs and shorten the washing time of CPAs, choosing hollow fiber modules with low CPA permeabilities, increasing blood flow rates and decreasing dialysate flow rates are highly recommended.

ESRD care in Bhutan: Common themes and unique challenges

ESRD care in Bhutan: Common themes and unique challenges

Kt calculation as a quality indicator of haemodialysis adequacy

The haemodialysis dose is a good marker of dialysis adequacy, and we usually monitor it with Kt/V measure. The dialysis dose monitored with Kt allows a better discrimination, detecting a percentage of the patients that perhaps do not get an adequate dose for their gender or body surface area after treatment with a minimum recommended dose of Kt/V. The objective of this study was to evaluate Kt as a clinical indicator referred to dialysis adequacy in the haemodialysis population. The aim was that more than 85% of the patients would achieve the recommended Kt target for their gender (at least 50 litres in men and 45 litres in women), or their body surface area. In each of the patients (mean 129) the Kt mean value was determined for three consecutive dialysis sessions, one every two months, during the follow-up period (14 months). At the beginning, the Kt/V value was on target (> 1.3) in 93.2% of the patients, but only in 58% according to Kt measure for their gender. After 4 months, we observed that 85% of patients' Kt target increased for their gender, but only 68% did if we used the Kt individualised for their body surface area. From month 6 to the end of the follow-up period, more than 85% of patients obtained an adequate Kt for their body surface area (p < 0.001). A significant increase of Kt mean (5.4 litres) was observed at the end of the study (p < 0.001). The usual dialysis prescription parameters were modified increasing blood flow rate (34.14 ml/min, p < 0.001), session effective duration (8.04 minutes, p < 0.001), dialyser surface area (24.1% of patients changed from helixone 1.3 to 1.6 m2, p < 0.001) and haemodialysis modality (56.8% of patients changed from conventional haemodialysis to on-line haemodiafiltration, p < 0.001). We conclude that monitoring dialysis dose with Kt is a good clinical measure of adequacy, and using it as a quality indicator can be done in line with the more demanding quality standards.

A Steady-State Mass Transfer Model of Removing CPAs From Cryopreserved Blood With Hollow Fiber Modules

Hollow fiber modules are commonly used to conveniently and efficiently remove cryoprotective agents (CPAs) from cryopreserved cell suspensions. In this paper, a steady-state model coupling mass transfers across cell and hollow fiber membranes is theoretically developed to evaluate the removal of CPAs from cryopreserved blood using hollow fiber modules. This steady-state model complements the unsteady-state model, which was presented in our previous study. The steady-state model, unlike the unsteady-state model, can be used to evaluate the effect of ultrafiltration flow rates on the clearance of CPAs. The steady-state model is validated by experimental results, and then is compared with the unsteady-state model. Using the steady-state model, the effects of ultrafiltration flow rates, NaCl concentrations in dialysate, blood flow rates and dialysate flow rates on CPA concentration variation and cell volume response are investigated in detail. According to the simulative results, the osmotic damage of red blood cells can easily be reduced by increasing ultrafiltration flow rates, increasing NaCl concentrations in dialysate, increasing blood flow rates, or decreasing dialysate flow rates.

Hemodialysis, plea of availability versus adequecy gezira experience

Objectives: This is a prospective cross sectional study carried out in Gezira Hospital for Renal Diseases and Surgery (Sudan) to assess the adequacy of hemodialysis in 206 patients with end stage kidney disease on regular hemodialysis twice per week using.Methods: Pre and post hemodialysis blood sample were obtained from the study group, spKt/V and urea reduction ratio were calculated.Results: Mean Kt/v was found to be 1.19 and urea reduction ratio was 59.55%. None of the patients in this study group achieved the National Kidney Foundation Dialysis Outcomes Quality Initiative (K/DOQI) recommendations for adequate hemodialyis, since it requiresthree hemodialyis sessions per week and our patients are receiving two sessions per week.Conclusion: In order to improve the situation herewith we recommended increased number of sessions from two to three times per week and \or increase the duration of hemodialysis session, increase blood flow rate and dialysate flow rate. Moreover, decrease the number of patients onregular hemodialysis by encouraging the patients to take the other renal replacement therapy (peritoneal dialysis and renal transplantations).

96 HOURS EVALUATION OF A COMPACT GAS EXCHANGER FOR AMBULATORY ARTERIO-VENOUS CARBON DIOXIDE REMOVAL (AVCO2R)

With the goal of developing an ambulatory AVCO2R system, we have tested the performance characteristics of a downsized gas exchanger (1.3 m2, uncoated x30–240 Celgard hollow fibers) with an injection-molded polycarbonate housing (MC3, Inc., Ann Arbor, MI) in a 96 hour healthy sheep model. Methods: The gas exchanger was attached from the carotid artery (12F) to the jugular vein (14F) of adult sheep (n=3) by percutaneous cannulae. ACT was maintained between 160–240 Sec by continuous intravenous heparin. Hemodynamics, blood gases, CBC, and CO2 removal were recorded at 6th, 24th, 48th, 72nd and 96th hour. CO2 removal was measured at a constant blood flow rate (Qb) of 1 L/min with varying sweep gas (Qg) from 1 to 15 L/min, and at constant Qg of 5 L/min with varying Qb from 0.5 to 1.5 L/min to determine the capacity of CO2 removal. Results: Hemodynamics and blood hemoglobin level remained stable throughout the study. CO2 removal utilizing this downsized gas exchanger varied with changes in device blood flow and sweep gas flow rate. CO2 removal with Qb=1L/min and Qg=5L/min was 107±11, 92±13, 90±15, 71±28 and 81±23 mL/min at 6, 24, 48, 72 and 96 hours, respectively. At Qg=5L/min, CO2 removal by the gas exchanger directly correlated with increasing blood flow rate (R2=0.997, P<0.001). During autopsy, clotting was observed in the distal end of all gas exchange devices. Conclusion: This downsized gas exchanger achieves stable, near total resting CO2 removal for 96 hours with a simple arteriovenous shunt.

Sequential changes in vessel formation and micro-vascular function during bone repair

Background Angiogenesis, the process of new vessel formation from a pre-existing vascular network, is essential for bone development and repair. New vessel formation and microvascular functions are crucial during bone repair, not only for sufficient nutrient supply, transport of macromolecules and invading cells, but also because they govern the metabolic microenvironment. Despite its central role, very little is known about the initial processes of vessel formation and microvascular function during bone repair.Methods To visualize and quantify the process of vessel formation and microvascular function during bone repair, we transplanted neonatal femora with a substantial defect into dorsal skin-fold chambers in severe combined immunodeficient (SCID) mice for continuous noninvasive in-vivo evaluation. We employed intravital microscopic techniques to monitor effective microvascular permeability, functional vascular density, blood flow rate and leukocyte flux repeatedly over 16 days. Oxytetracyclin and v. Kossa/v. Giesson staining was performed to quantify the calcification process in vivo and in vitro.Results Development of a hematoma surrounding the defect area was the initial event, which was accompanied by a significant increase in microvascular permeability and blood flow rate. With absorption of the hematoma and vessel maturation, permeability decreased continuously, while vascular density and tissue perfusion increased. Histological evaluation revealed that the remodeling of the substantial defect prolonged the in-vivo monitored calcification process.Interpretation The size of the initial substantial defect correlated positively with increased permeability, suggesting improved release of permeability-inducing cytokines. The unchanged permeability in the control group with boiled bones and a substantial defect corroborated these findings. The adaptation to increasing metabolic demands was initially mediated by increased blood flow rate, later with increasing vascular density through increased tissue perfusion rate. These insights into the sequence of microvascular alterations may assist in the development of targeted drug delivery therapies and caution against the use of permeability-altering drugs during bone healing.

Feasibility of Continuous CO2 Removal with Hydrophilic Membranes at Low Blood Flow Rates

In the conventional treatment of acute respiratory distress syndrome (ARDS), high O2 concentrations and mechanical ventilation may damage the lung tissue. Extracorporeal membrane oxygenation limits damage, provides the needed O2 supply and improves survival of ARDS neonates, but not of adults. Hydrophilic membranes used in hemodialysis are more non-thrombogenic and biocompatible than those used in blood oxygenation, but their O2 transport capacity is not as high. In recent years, CO2 removal at low blood flow rates combined with apneic oxygenation and low frequency ventilation has proved promising in the treatment of ARDS. This approach makes O2 supply across ECMO membranes unnecessary; it also makes hydrophilic membranes candidates for extracorporeal CO2 removal to minimize anticoagulation and immune system activation. This paper reports on the in vitro capacity of hydrophilic polysulphone membranes to remove CO2 from carbonated pig blood into an oxygen-rich gas stream. Experiments were performed on clinical-size dialysis modules and their capacity to remove CO2 as a function of blood flow rate and membrane surface area was investigated. Membranes effectively removed CO2 , more so at increasing blood flow rates and membrane surface areas, at rates of up to 15% of the CO2 metabolic production rate. The specific CO2 removal rate was comparable to that of blood oxygenators equipped with microporous hydrophobic membranes. It is concluded that CO2 removal from slowly flowing blood with hydrophilic membranes is feasible.

The effect of dialysis needle size on hemodialysis adequacy

Objective: Dialysis adequacy indexed by Kt/V in hemodialysis (HD) patients is recommended as a single pool Kt/V at least 1.2 per session thrice weekly. But many patients cannot achieve this adequacy target. Although dialysis time is the most important factor influencing Kt/V, it is difficult to prolong dialysis time in practice because of its economic impact and poor patient compliance. This study was performed to investigate the effect of increasing dialysis needle size on dialysis adequacy in HD patients. Methods: This study enrolled 73 patients receiving HD thrice weekly for more than 3 months with arteriovenous fistula (AVF) or graft in a single center. Dialysis blood flow rate was 200 ml/min in 12 patients, 250 ml/min in 32 patients, and 300 ml/min in 29 patients. Surface area of dialyzer was 1.2 m2 in 56 patients and 1.6 m2 in 17 patients. We first performed HD using a 16‐gauge needle. Then we increased needle size up to 15‐gauge without change of any other dialysis conditions such as blood and dialysate flow rates, dialysis time, or distance between needle insertion sites. We compared compression time after removing the needles, venous dialysis pressure (VDP), Kt/V, and urea reduction ratio (URR) between these two methods. Results: The mean age was 54 ± 13 years and the number of patients with diabetes mellitus was 27 (37%). Fifty‐eight patients (79.5%) have native AVF. Mean Kt/V at HD method using a 15‐gauge needle was higher than at HD method using a 16‐gauge needle (1.30 ± 0.18 vs. 1.23 ± 0.18, p &lt; 0.001). URR at HD method using a 15‐gauge needle was also higher than at HD method using a 16‐gauge needle. In contrast, VDP at HD method using a 15‐gauge needle was lower than at HD method using a 16‐gauge needle (88 ± 22 mmHg vs. 118 ± 28 mmHg, p &lt; 0.001). There was no difference in compression time between the two methods. Conclusion: This study suggests that increasing dialysis needle size is a safe and effective method in improving dialysis adequacy without increasing blood flow rate or dialysis time.

The Effect of Increasing Blood Flow Rate on Dialysis Adequacy in Hemodialysis Patients with Low Kt/V

Dialysis adequacy indexed by Kt/V in hemodialysis (HD) patients is recommended as a single‐pool Kt/V of at least 1.2 per session thrice weekly. But many patients cannot achieve this adequacy target. Although dialysis time is the most important as a factor influencing Kt/V, it is difficult to prolong dialysis time in practice because of its economic impact and poor patient compliance.Objective: The aim of this study is to investigate the effect of increasing blood flow rate on dialysis adequacy in HD patients with low Kt/V.Methods: This study enrolled 36 HD patients with single‐pool Kt/V &lt;1.2 per session thrice weekly, which was measured in dialyzer blood flow rate of 230 mL/min. We increased 15% of blood flow rate in patients &lt;65 kg of body weight and 20% in patients &gt;65 kg. And then we compared Kt/V and urea reduction ratio (URR) between before and after increasing blood flow rate.Results: The mean age was 48 ± 11 years (23–73 years), and the number of males was 25. Of the total patients, 24 patients had dry weight &lt;65 kg. Mean dialysis duration was 52 ± 50 months (3–216 months). Mean Kt/V before increasing blood flow rate was 1.02 ± 0.09. It increased to 1.14 ± 0.12 after increasing blood flow rate (p &lt; 0.001). Of the total 36 patients, 13 patients (36.1%) achieved adequacy target (Kt/V ≤ 1.2). Mean URR before increasing blood flow rate was 56.9 ± 4.0%. It also increased to 60.8 ± 4.1% (p &lt; 0.001).Conclusion: Our data suggest that increasing blood flow rate by 15–20% of previous flow rate is effective in achieving dialysis adequacy in HD patients with low Kt/V.

Application of the ultrasound hyperthermia model for a multi-layered tissue system

This work models the thermal effect of several planar transducers targeting thetumour interactively in a ceramics-coupling-skin-muscle-tumour system. The most importantinputs of the model include the following: emitted electric output, J/s; mechanical efficiency,%; number of transducers, pieces; surface area of the transducer, m2; area, m2 and temperature,K of the cooling surface, attenuation coefficients, Np/cm MHz; specific heats, J/gK; densities,g/cm3; heat conductivities, J/msK; sound velocities m/s; flow rate of blood in the tissues,ml/gtissue/min; sound path in the tissues and in the blood flowing through the tissues, m. Fromthe inputs, a number of intermediate data are determined, e.g. the geometry of the irradiatedbodies that are in the path of ultrasound, acoustic hardness, Pas/m; sound reflection and soundtransmission occurring at the interfaces, Np; heat exchanger wall thickness of the irradiatedbodies, m; heat dissipation and heat exchanger surface areas, m2; flow rate of blood in thetissues located in the path of ultrasound, ml/tissue mass in g/min; and the sound attenuation ofthe tissues, Np. The amount of generated heat, K/s decreased by the heat energy transported,J/s to the surrounding tissues by blood and heat conductivity, and the actual temperature, K ofthe irradiated tissue are the output parameters calculated by the model. The output results areavailable in the form of functions. The expected temperature of the target area, K can be set toeither the denaturation temperature or to the respiratory decomposition temperature (43.5°C)without damaging the surrounding tissues by setting in the following parameters properly:electric output power, W; the number and surface area, m2 of the transducers; the area, m2 andtemperature, K of the cooling surfaces. After further development, the model will be suitablefor handling more than three tissue layers, increased blood flow rates different angles ofincidence, and tumours having different geometric shape.

Effect of Nimodipine on Histological Alterations in Basilar Artery Following the Bilateral Common Carotid Artery Ligation (Preliminary Study)

The blood supply to tissues is reduced as a result of arterial occlusions. Angiogenesis, collateral circulation and reverse flow mechanisms go into operation to restore a continued adequate supply of blood. Ca++ channels undertake the major part of this function. As a result of the increasing tension on the arterial walls, vascular autonomy is affected, and ischemia and even necrosis are observed. Adult 100 male hybrid rabbits were used in this study. The bilateral carotid arteries were ligated at the carotid bifurcation. The rabbits were divided into 2 main groups: treatment and control, and then both groups were further divided into 5 subgroups consisting of 10 rabbits each. The rabbits were sacrificed between the first day and the end of 8 weeks for histopathological examination of the basilar artery in two groups. In control groups, after 24 hours of the occlusion partial swelling and minor endothelial damage were observed in histopathological sections of the basilar artery. Luminal flattening started to decrease, and expanding of the diameter continued. The increase in the diameters of the basilar artery was higher in animals treated by nimodipine, and that difference was statistically significant (P=0,000). This study revealed that the intimal and medial alterations arising from the increased blood flow rate in the basilar artery might be lessened and even partially prevented by the use of nimodipine.

腓腹筋・ハムストリングストレッチング装置の開発と評価(S47-1 介護・福祉装置,S47 健康・福祉機器の開発)

Blood in lower position is said to be pumped up to a heat by calf muscle. So stretching of an Achilles' tendon is good for our health. Stretching is quite easy for a healthy person, but it is not easy for either the aged or a disabled person. Accordingly the hamstring stretching equipment was developed and evaluated. As the results of this research, the blood flow rate was closely related to the pedal angle of stretching equipment. Through our research, it was concluded that varying the pedal angle was recommended for the sake of increasing blood flow rate. The change of blood flow rate was not observed in stretching goods on the market.

Racial disparities in kidney health: The puzzle to solve

Racial disparities in kidney health: The puzzle to solve

Prospective, randomized evaluation of a cuffed expanded polytetrafluoroethylene graft for hemodialysis vascular access

Background. A cuffed expanded polytetrafluoroethylene (ePTFE) hemodialysis graft was developed to address the problem of recurrent stenosis at the graft-vein anastomosis. The purpose of this study was to compare graft patency and blood flow rates of cuffed and noncuffed (standard) ePTFE grafts placed for hemodialysis access. Methods. Forty-eight patients were prospectively randomized and followed for up to 24 months after placement of a cuffed or standard ePTFE graft for hemodialysis access. Study end points included time to graft failure and blood flow rates on hemodialysis. Results. Risk factors for graft failure were similar in both groups. However, the overall incidence of graft failure was significantly lower in the cuffed ePTFE graft group (P =.039). Graft patency rates in the cuffed versus standard groups were 64% versus 32% at 12 months (P =.037) and 58% versus 21% at 24 months (P =.0213). No cuffed ePTFE graft failed as a result of venous outflow stenosis. Average graft flow rates were similar when first measured 3 months postoperatively (845 mL/min, cuffed vs 715 mL/min, standard; P =.51) but declined more rapidly in the standard group (12 months, 623 vs 253 mL/min [P =.037]; 24 months, 531 vs 121 mL/min [P =.012]). Conclusions. The cuffed ePTFE graft was associated with increased blood flow rates during hemodialysis and improved graft patency compared with a standard ePTFE graft. Our results suggest a beneficial effect of the cuffed venous geometry for hemodialysis vascular access. (Surgery 2002;132:135-40.)