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On the Horizon: Growing a Reliable Source of Veins
for Coronary Artery Bypass Surgery
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BIOENGINEERED VEINS OFFER NEW HOPE ON HORIZON FOR PATIENTS LACKING HEALTHY VEINS FOR CORONARY BYPASS SURGERY OR DIALYSIS
More than 500,000 patients could potentially benefit from this new technology each year
RESEARCH TRIANGLE PARK, N.C., Feb. 2, 2011 /PRNewswire/ — The day when a surgeon can pull a new human vein “off the shelf” for use in life-saving vascular surgeries is now one step closer to reality. New research published in the current issue of the journal Science Translational Medicine demonstrates the efficacy of tissue-engineered vascular grafts (TEVGs) that are immediately available at the time of surgery and have decreased potential for infection, obstruction or clotting. The bioengineering method of producing veins reported in the newly-published research shows promise in both large and small diameter applications, such as for Coronary Artery Bypass Graft (CABG) surgery and for vascular access in hemodialysis.
Coronary Artery Bypass Graft (CABG) Surgery
The American Heart Association Update on Heart Disease Statistics reports that in 2007, in the U.S., just over 400,000 coronary bypass procedures were performed. Patients requiring bypass surgery may not have suitable veins or arteries available and are not candidates for synthetic grafts because of the size needed for grafting.
“This new type of bioengineered vein allows them to be easily stored in hospitals so they are readily available to surgeons at the time of need,” said Alan P. Kypson, M.D., Associate Professor of Cardiothoracic Surgery, Brody School of Medicine, at East Carolina University, also an author of the paper. ”Currently, grafting using the patient’s own veins remains the gold standard. But, harvesting a vein from the patient’s leg can lead to complications, and for patients who don’t have suitable veins, the bioengineered veins could serve as an important new way to provide a coronary bypass.”
Kidney Hemodialysis
According to statistics published by the National Kidney Foundation, 320,000 patients are on chronic hemodialysis. Each year, 110,000 new patients develop renal failure requiring dialysis, and the number is growing by three percent per year. More than half of dialysis patients lack the healthy veins necessary and must undergo an arteriovenous graft (AV graft) placement in order to have bloodstream access for hemodialysis.
“Most AV grafts that are placed for hemodialysis access are comprised of a synthetic material, which suffers from significant drawbacks including a high rate of infection, or a propensity for occlusion due to thrombosis and intimal hyperplasia,” said Jeffrey H. Lawson, M.D., Ph.D., Associate Professor of Surgery at Duke University School of Medicine and an author of the research. “Due to high complication rates, each AV dialysis graft requires an average of 2.8 interventions over its lifetime just to keep it functioning. Hence, there is a huge clinical need for a functionally superior, off-the-shelf, AV graft that suffers from fewer complications than current materials.”
The research was conducted by scientists from Duke University, East Carolina University, Yale University, and Humacyte, and was funded by Humacyte, a leader in regenerative medicine. Overseeing the research and senior author of the article was Laura Niklason, M.D., Ph.D., founder of Humacyte, and Professor of Anesthesiology and of Biomedical Engineering at Yale University. Niklason is a recognized authority in regenerative medicine for arterial engineering and was leader of the team that recently created a functioning rat lung in a laboratory.
“Not only are bioengineered veins available at the time of patient need, but the ability to generate a significant number of grafts from a cell bank will allow for a reduction in the final production costs, as compared to other regenerative medicine strategies,” added lead author Shannon L. M. Dahl, Senior Director of Scientific Operations and Co-Founder of Humacyte, Inc. “While there is still considerable research to be done before a product is available for widespread use, we are highly encouraged by the results outlined in this paper and eager to move forward with additional study,” Dahl said.
About The Research
In this research, bioengineered veins were generated in a bioreactor, decellularized, and stored up to 12 months in refrigerated conditions. Then bioengineered veins (3-6mm in diameter) demonstrated excellent blood flow and resistance to occlusion in large animal models for up to one year.
About Humacyte
Humacyte, a privately held company, is primarily focused on developing products for vascular disease and for dermal filling and soft tissue repair. The company uses its innovative and proprietary platform technology to engineer human, extracellular matrix-based tissues that can be shaped into tubes, sheets, or particulate conformations, with properties similar to native tissues. These can then be used in many specific applications, with the potential to significantly improve treatment outcomes for a variety of patients, including those with diabetes and on hemodialysis. The company's proprietary technologies are designed to result in off-the-shelf products that can be utilized in any patient. The company Web site is www.humacyte.com.
Forward-Looking Statement
Information in this news release contains “forward-looking statements” about Humacyte. These statements, including statements regarding management’s projections relating to future results and operations, are based on, among other things, management’s views, assumptions and estimates, developed in good faith, all of which are subject to known and unknown factors that may cause actual results, performance or achievements, or industry results, to differ materially from those expressed or implied by such forward-looking statements.
Dr. Lawson has served as a consultant for Humacyte and has also received research support from the company through Duke University. |
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Featured Angina| Acute Coronary Syndrome and Heart Disease Interviews
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Highlights of Article by Dr. Erik Hess et of Mayo Clinic ;CIRCOUTCOMES 2012
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Chest pain is the 2nd most common reason patients come to EDs across the United States
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Initial testing – including information obtained from the history, physical exam, electrocardiogram, and cardiac troponin – identifies > 98% of heart attacks
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To avoid missing a diagnosis of heart attack or pre-heart attack symptoms, emergency physicians often admit patients to observation units or to the hospital for extensive diagnostic testing, including stress testing
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This results in false positive test results, unnecessary exposure to radiation, and unnecessary downstream procedures such as stent placement in arteries of the heart
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Decision aids are evidence-based tools designed to educate and engage patients in decisions regarding their care
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We hypothesized that patients who were educated regarding their future risk for a heart attack and engaged in the decision of whether to be admitted to the observation unit for stress testing or to follow-up with a Mayo Clinic heart doctor in the next 72 hours would have greater knowledge about their short-term risk for heart attack, be more aware of the management options, and choose less intensive approaches to evaluation
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We randomly assigned 204 patients who came to the ED with chest pain and were being considered for observation unit admission to the decision aid or to usual care
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Decision aid patients:
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Had greater knowledge regarding their short-term risk for a heart attack
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Less frequently decided to be admitted to the observation unit for stress testing
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Had 4 times greater engagement in the decision making process
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Had no adverse events within 30 days of the ED visit
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Take home points
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Patients want to be educated and engaged in decisions regarding their care
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Once properly informed and engaged in treatment decisions, patients often choose less intensive treatment options
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Integrated health systems like the Mayo Clinic in which physicians collaboratively work together to provide ER patients ready access to outpatient follow-up have potential to improve the value of Emergency care
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Glucose, Insulin and Potassium (“GIK”) TO MINIMIZE IMPACT OF HEART ATTACKS BEFORE PATIENTS GET TO THE HOSPITAL
Study puts life-saving drugs in the hands of paramedics, decreasing rate of cardiac arrest and death from heart attacks
CHICAGO (March 27, 2012) — Paramedics can potentially reduce someone’s chances of having a cardiac arrest or dying by 50 percent by immediately administering a mixture of glucose, insulin and potassium (“GIK”) to people having a heart attack, according to research presented today at the American College of Cardiology’s 61st Annual Scientific Session. The Scientific Session, the premier cardiovascular medical meeting, brings cardiovascular professionals together to further advances in the field.
The study showed that patients who received GIK immediately after being diagnosed with acute coronary syndrome — which indicates a possible heart attack is either in progress or on the way — were 50 percent less likely to have cardiac arrest (a condition in which the heart suddenly stops beating) or die than those who received a placebo, although the treatment did not prevent the heart attack from occurring. The reduction in in-hospital cardiac arrest or death was a “secondary endpoint”, so statistically was not definitive, but was consistent with how GIK seems to work in experimental models of heart attack.
The effect was also present for patients with ST-elevation heart attacks, which require immediate treatment. For those patients, immediate GIK was associated with a 60 percent reduction in in-hospital cardiac arrest or death.
“When started immediately in the home or on the way to the hospital — even before the diagnosis is completely established — GIK appears not completely prevent any heart attack from occurring, but appeared in this trial to reduce the size of heart attacks and to reduce by half the risk of having a cardiac arrest or dying,” said Harry P. Selker, MD, MSPH, executive director of the Institute for Clinical Research and Health Policy Studies at Tufts Medical Center, who led the study with Joni Beshansky, RN, MPH, co-principal investigator and project director. “Acute coronary syndromes represent the largest cause of death in this country. GIK is a very inexpensive treatment that appears to have promise in reducing those deaths and morbidity.”
The cost of the treatment is about $50.
“Because the trial is the first to show GIK could be effective when used by paramedics in real-world community settings, it could have important implications for the treatment of heart attacks,” Dr. Selker said. Previous clinical trials have shown no consistent effect, likely because the GIK was given too late to help. This study, the “IMMEDIATE Trial,” was the first to test the effectiveness of administering GIK at the very first signs of a threatening heart attack, in the community, rather than waiting hours until the diagnosis was well-established at a hospital, as done in previous clinical trials.
“We wanted to do something that is effective and can be used anywhere,” said Dr. Selker. “We’ve done a lot of studies of acute cardiac care in emergency departments and hospitals, but more people die of heart attacks outside the hospital than inside the hospital. Hundreds of thousands of people per year are dying out in the community; we wanted to direct our attention to those patients.”
The researchers trained paramedics in 36 Emergency Medical Services systems in 13 cities across the country to administer GIK after determining that a patient was likely having a threatened or already established heart attack using electrocardiograph-based ACI-TIPI (acute cardiac ischemia time-insensitive predictive instrument) and thrombolytic predictive instrument decision support that prints patient-specific predictions on the top of an electrocardiogram. The paramedics used these predictions to decide if a patient would likely benefit from treatment. There were 911 patients randomized to receive either the GIK treatment or a placebo.
Administering GIK immediately also reduced the severity of the damage to the heart tissue from the heart attack. On average, 2 percent of the heart tissue was destroyed by the heart attack in people receiving GIK, compared with 10 percent in those who received the placebo. Although a significant proportion of suspected heart attacks are later determined to be false alarms (23 percent in this study), administering GIK does not appear to cause any harmful effects in such patients.
The research team will follow up with study participants at six and 12 months to evaluate the longer-term benefit of the GIK treatment.
This study was funded by the NIH’s National Heart, Lung and Blood Institute.
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Keywords and tags:
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Angina | Heart Disease Resourses
| Chest Pain
Amazon.com 's Editorial Reviews
Angina: New Ways to Treat
Chronic Chest Pain
Part of the award winning public television series Healthy head
/Healthy Mind. It's one of the scariest medical symptoms for people who are generally healthy: a tightening, painful feeling in the chest known as Angina. In some cases this chest pain can be a serious warning that requires immediate treatment. But for the millions of people with chronic, stable angina the discomfort is something that can be readily managed with a variety of treatments. In this program we take a look at what generally causes angina, what can be done to prevent it and how it can be effectively treated with lifestyle changes, innovative drug therapies and medical procedures.
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Amazon.com Editorial Review:
Philips HeartStart Home Defibrillator (AED)
Be prepared for the unexpected.
When sudden cardiac arrest (SCA) strikes, the electrical system of the heart short circuits, causing the heart to quiver rather than pump in a normal rhythm. It typically results in the abnormal heart rhythm know as ventricular fibrillation (VF). It usually happens without warning and the majority of people have no previously recognized symptoms of heart disease. And it most often happens at home. For the best chance of survival from SCA caused by VF, a defibrillator should be used within 5 minutes. Yet, less than 1 in 20 people survive largely because a defibrillator does not arrive in time.
Just as seat belts or airbags do not save every life in a traffic accident, a defibrillator will not save every person who suffers a sudden cardiac arrest. Yet many lives could be saved if more people could be reached more quickly.
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