How Rocket Science May Improve Kidney Dialysis - Newswise (press release)
Software from the aerospace industry has allowed an interdisciplinary team of U.K. researchers to design Arterio-Venous Fistulae with better, less unnatural flow patterns, which may reduce failure rates and improve clinical outcomes for patients with kidney failure who require dialysis.
Newswise — WASHINGTON, D.C., March 17, 2015 -- A team of researchers in the United Kingdom has found a way to redesign an artificial connection between an artery and vein, known as an Arterio-Venous Fistulae, which surgeons form in the arms of people with end-stage renal disease so that those patients can receive routine dialysis, filtering their blood and keeping them alive after their kidneys fail.
The new design, described in the journal Physics of Fluids, from AIP Publishing, may decrease the likelihood of blockages in Arterio-Venous Fistulae, which is a major complication of dialysis.
While the AVF would have to prove effective in clinical trials before they could be deemed a success, the researchers are enthusiastic about their approach, which used software from the aerospace industry to design the novel configurations.
"At the moment, the process of creating an Arterio-Venous Fistulae for dialysis is rather 'one-size-fits-all'," said Peter Vincent, a senior lecturer and EPSRC early career fellow in the Department of Aeronautics at Imperial College London. "Our ultimate aim is to use computational simulation tools to design tailored, patient-specific Arterio-Venous Fistulae configurations that won't block and fail."
Dialysis and Chronic Kidney Disease
Dialysis is a life-saving treatment for end-stage renal disease -- the last stage of chronic kidney disease -- a serious and often fatal health condition in which a person's kidneys become damaged and can no longer filter blood as effectively as healthy kidneys. As a result, wastes from the blood remain within the body and often lead to other health problems such as cardiovascular disease, anemia and bone disease.
Chronic kidney disease is a global health challenge. For perspective, in the United States alone, the Centers for Disease Control and Prevention estimates that more than 20 million adults -- more than 10 percent of the U.S. adult population -- may have the disease, although many are undiagnosed. Kidney disease is now the 9th leading cause of death in the U.S.
Once a person's kidney's fail, they require either a kidney transplant or regular treatment via a dialysis machine to keep filtering the blood like a kidney. Transplant surgeries often have very good outcomes, but the procedures are limited by the availability of donated kidneys, and only a few thousand become available every year in the United States, while tens of thousands of people are on the waiting list for a kidney transplant. People often wait for a new kidney transplant for years, having to undergo periodic dialysis the entire time.
One problem that arises with dialysis is that the connections made between the body and a dialysis machine via an Arterio-Venous Fistulae frequently become blocked and fail shortly after they are created -- leading to unfavorable clinical outcomes and a significant additional cost burden for healthcare systems worldwide.
So an interdisciplinary team of U.K. researchers -- including members from aeronautics, bioengineering, computational engineering, medical imaging and clinical medicine -- from Imperial College London, Imperial College Renal and Transplant Centre at Hammersmith Hospital, and St. Mary's Hospital set out to design an Arterio-Venous Fistulae with reduced failure rates.
Design Based on Aerospace Software
To do this, the researchers first needed to gain a better understanding of how arterial curvature affects blood flow and oxygen transport patterns within Arterio-Venous Fistula.
Blood flow patterns within AVF are "inherently 'un-natural,' and it's thought that these unnatural flow patterns lead to their ultimate failure," explained Vincent.
By using computational simulation software originally developed for the aerospace sector, the team is able to simulate and predict flow patterns in various Arterio-Venous Fistula configurations. "This allows us to design Arterio-Venous Fistula with much more natural flow patterns, which will hopefully reduce failure rates," Vincent said.
The team "identified ways of constructing Arterio-Venous Fistula such that the flow is stabilized," he added. "We discovered that if an Arterio-Venous Fistulae is formed via connection of a vein onto the outside of an arterial bend, it stabilizes the flow."
The implications of this work are tremendous, because it may now finally be possible to design an Arterio-Venous Fistulae with reduced failure rates -- offering improved clinical outcomes for patients with kidney failure who require dialysis.
The article, "The Effect of In-Plane Arterial Curvature on Blood Flow and Oxygen Transport in Arterio-Venous Fistulae," is authored by F. Iori, L. Grechy, R.W. Corbett, W. Gedroyc, N. Duncan, C.G. Caro and P. Vincent. It appears in the journal Physics of Fluids on March 17, 2015 (DOI: 10.1063/1.4913754). After that date, it may be accessed at: http://scitation.aip.org/content/aip/journal/pof2/27/3/10.1063/1.4913754
The authors of this paper are affiliated with Imperial College London, Imperial College Renal and Transplant Centre at Hammersmith Hospital and St. Mary's Hospital.
ABOUT THE JOURNAL
Physics of Fluids is devoted to the publication of original theoretical, computational, and experimental contributions to the dynamics of gases, liquids, and complex or multiphase fluids. See: http://pof.aip.org
Congress revives efforts to fix doc payment formula - NephrologyNews.com
Congress is racing toward a March 31 deadline to replace the much-maligned sustainable growth rate formula, used to determine Medicare payment for physicians, with a more progressive pay-for-performance model. Missing the deadline would mean nephrologists and other specialists paid by Medicare will face a more than 20% payment cut April 1.
Legislators came close to a new payment formula last year, but could not agree on how to pay for it. President Barack Obama signed into law legislation that provided a temporary one-year patch for the SGR last April.
The latest deal would offset only about $70 billion of the more than $200 billion cost of making the permanent fix. Late in the afternoon on March 13 , Reps. Paul Ryan, R-Wis., Sander Levin, D-Mich., Fred Upton, R-Mich., and Frank Pallone, D-N.J., the top members of two key committees, confirmed they are in talks for a permanent fix.
“Last year, the Ways and Means and Energy and Commerce Committees came together, on a bipartisan basis, to propose a permanent alternative to the broken SGR system," they said in a statement. "We are now engaging in active discussions on a bipartisan basis — following up on the work done by leadership — to try to achieve an effective permanent resolution to the SGR problem, strengthen Medicare for our seniors, and extend the popular Children’s Health Insurance Program."
Ryan and others are proposing a two-year extension of the Children’s Health Insurance Program (CHIP). The deal would be a compromise for Democrats, who hoped for a four-year extension of the program.
The “doc fix” portion would cost an estimated $174 billion of the $200 billion, spread over 10 years, according to the Congressional Budget Office.
Adherence to four lifestyle factors can lower the risk of death in CKD patients, according to a new study in the American Journal of Kidney Diseases.
The study found that CKD patients who don’t smoke, are physically active, eat a healthy diet (comprised of more fruits, vegetables and whole grains and less red meat and sugar) and have a body mass index between 20-25 kg/m2, reduced their risk of death by 68% compared to those who did not have these lifestyle qualities.
"We have learned from research studies of other chronic conditions such as heart disease and cancer that lifestyle factors and behaviors including diet, physical activity, cigarette smoking, and body mass index play a very important role in health outcomes including cardiovascular events and mortality,” said Ana C. Ricardo, MD, MPH, Assistant Professor of Medicine, University of Illinois, Chicago. “We wanted to know if these factors were as important in individuals with chronic kidney disease, and it appears they are.”
Using data collected during four years of follow-up from 3,006 adults enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study, researchers tracked the relationship between lifestyle factors and health outcomes such as chronic kidney disease progression, heart disease and death. Patients had a mean age of 58 ± 11, a mean eGFR of 43 ± 14 mL/min/1.73 m2, and 45% of them had diabetes.
Over four years, there were 726 cases of worsening kidney function, 355 heart events, and 437 deaths. Those who did not smoke cigarettes had better outcomes including slower progression of CKD, and reduced risk of heart attacks and death. Regular physical activity was also associated with reduced risk of death.
Somewhat surprisingly, a body mass index greater than 25 kg/m2was associated with lower risk of cardiovascular events while a body mass index greater than 30 kg/ m2 was associated with lower risk of death.
Healthy diet patterns, independently, didn’t predict better outcomes, but increased survival when combined with nonsmoking, regular exercise and a BMI between 20-25 kg/m2. All together, adherence to all four lifestyle factors was associated with a 68% decrease in risk of death.
“This demonstrates that a holistic approach that incorporates all aspects of a person’s lifestyle and behavior can have the most impact on improving life expectancy in those with CKD,” said Thomas Manley, Director of Scientific Activities for the National Kidney Foundation. “Healthy lifestyle modifications have consistently been shown to improve a patient’s prognosis, so it makes sense for healthcare practitioners to put more emphasis on helping their patients with CKD adopt healthy daily routines and habits.”
Aside from the surprising results of the body mass index on outcomes, all four lifestyle modifications were not associated significantly with CKD progression or heart events, indicating that more research is needed in this area.
“Our findings reinforce clinical care guidelines which recommend lifestyle modifications, and suggest that current physical activity and nonsmoking recommendations for the general population are also applicable to individuals with CKD,” said Ricardo. “Furthermore, our findings suggest that additional research is needed to investigate the optimal dietary recommendations and body mass index levels to prevent disease progression and poor outcomes among individuals with CKD.”
Diabetic nephropathy: How does exercise affect kidney disease in T1DM? - Nature.com
Diabetic nephropathy: How does exercise affect kidney disease in T1DM? Nature.com Progression of nephropathy was defined by an increase in albuminuria from normoalbuminuria to microalbuminuria and from microalbuminuria to macroalbuminuria. The development of end-stage renal disease (ESRD; defined as commencement of dialysis ...
Log in to explore the world's most comprehensive database of dialysis centres for free! 
Professional dialysis recruitment
