{"284971":{"#nid":"284971","#data":{"type":"news","title":"Microfluidic Device With Artificial Arteries Measures Drugs\u2019 Influence on Blood Clotting","body":[{"value":"\u003Cp\u003EA new microfluidic method for evaluating drugs commonly used for preventing heart attacks has found that while aspirin can prevent dangerous blood clots in some at-risk patients, it may not be effective in all patients with narrowed arteries. The study, which involved 14 human subjects, used a device that simulated blood flowing through narrowed coronary arteries to assess effects of anti-clotting drugs.\u003C\/p\u003E\u003Cp\u003EThe study is the first to examine how aspirin and another heart attack prevention drug respond to a variety of mechanical blood flow forces in healthy and diseased arteries. Patients\u2019 blood was tested in a patent-pending microfluidic device with narrow passageways to simulate the coronary arteries. The data are consistent with clinical findings showing that physiology has a major influence on the effectiveness of drugs used for heart attack prevention.\u003C\/p\u003E\u003Cp\u003EThe researchers believe that a benchtop diagnostic device like the one used in this study could save lives by preventing heart attacks and help lower healthcare costs by giving physicians better guidance on how drugs may affect individual patients.\u003C\/p\u003E\u003Cp\u003E\u201cDoctors have many drug options and it is difficult for them to determine how well each of those options is going to work for a patient,\u201d said Melissa Li, who was a graduate student at the Georgia Institute of Technology at the time of the study. \u201cThis study is the first time that a prototype benchtop diagnostic device has tried to address this problem using varying shear rates and patient dosing and tried to make it more personalized.\u201d\u003C\/p\u003E\u003Cp\u003EThe study was sponsored by the American Heart Association, a Wallace H. Coulter Foundation Translational Grant and by a fellowship from the Technological Innovation: Generating Economic Results (TI:GER) program at Georgia Tech. The study was published in a recent edition of the journal \u003Ca href=\u0022http:\/\/dx.doi.org\/10.1371\/journal.pone.0082493\u0022\u003E\u003Cem\u003EPLOS ONE\u003C\/em\u003E\u003C\/a\u003E.\u003C\/p\u003E\u003Cp\u003EAbout 10 percent of the U.S. population takes drugs every day because they are at risk of a heart attack. When a patient comes to a hospital with heart disease, doctors have multiple treatment options, all with different routes of action, time scales and prices.\u003C\/p\u003E\u003Cp\u003E\u201cFor a patient being prescribed anti-thrombotic drugs who is at risk for a heart attack, we can draw a small amount of their blood and quickly push a little bit through this device, and based on that information, tell them to take a certain amount of a certain drug. That\u2019s where we\u2019re going with this project,\u201d said Craig Forest, an assistant professor of bioengineering in the George W. Woodruff School of Mechanical Engineering at Georgia Tech. Forest\u2019s lab led the study in collaboration with David Ku, a medical doctor and mechanical engineering professor at Georgia Tech. Ku is the Lawrence P. Huang Chair Professor of Engineering Entrepreneurship and a Regents\u0027 Professor of Mechanical Engineering.\u003C\/p\u003E\u003Cp\u003EFor the current study, researchers used the diagnostic device to examine two treatments for potential heart attacks: aspirin and a class of drugs called GPIIb\/IIIa-inhibitors. GPIIb\/IIIa-inhibitors are generally given to patients with a high risk for a heart attack, and these drugs can be expensive. The study found that the two drugs have very different effects on blood clotting.\u003C\/p\u003E\u003Cp\u003EWhen arteries are constricted, such as in patients with atherosclerosis, blood must squeeze through narrow passages. That pressurized flow induces a mechanical force called shear. Under high shear rates in arteries\u2014 blood flowing through a narrow opening \u2014 blood is more likely to clot. When blood is forced to squeeze through a small opening, platelets hook together, forming a clot.\u003C\/p\u003E\u003Cp\u003ETo show how these drugs affect clotting at high and normal shear rates, blood samples were drawn from patients over several days. The scientists added the two drugs at different doses to those blood samples and ran them through a microfluidic device. The microfluidic device has four channels that mimic the coronary arteries, allowing researchers to study clotting under a variety of conditions.\u003C\/p\u003E\u003Cp\u003E\u201cWhat we found is that with lower shear rates, such as found in normal arteries, aspirin was fairly effective at stopping platelets from clumping up with each other,\u201d said Li, who is now a postdoctoral fellow at the University of Washington. \u201cAt higher shear rates, aspirin was not as effective at preventing these clots.\u201d\u003C\/p\u003E\u003Cp\u003EThe researchers found that under high shear rates, clots still formed in the presence of aspirin, but that the clots became unstable and broke off the simulated artery walls.\u003C\/p\u003E\u003Cp\u003ELi said that their evidence suggests that aspirin should be fairly effective for most people at preventing heart attacks, but not as effective at preventing heart attacks in patients with atherosclerosis. This study can help identify which individuals can be helped, and which cannot.\u003C\/p\u003E\u003Cp\u003EThe current study would need to be replicated in a large, controlled study before this device can be moved to the clinic or hospital.\u003C\/p\u003E\u003Cp\u003E\u201cThis finding is something that\u2019s been echoed in the literature by physicians who would find that a number of patients who would take aspirin were not receiving any clinical benefit,\u201d Li said. \u201cThis is an explanation mechanically of why that might occur.\u201d\u003C\/p\u003E\u003Cp\u003EThat phenomenon has been called aspirin resistance, which is a catchall term for when patients don\u2019t respond to aspirin for unknown reasons.\u003C\/p\u003E\u003Cp\u003E\u201cWhat we showed is a good explanation for the conditions under which aspirin resistance occurs and one that matches up with what other people have found,\u201d Li said.\u003C\/p\u003E\u003Cp\u003EGPIIb\/IIIa-inhibitors were effective at preventing blood clots across all shear rates tested, the study found, suggesting that these drugs would be effective for people whether they had atherosclerosis. Clinical evidence also supports this finding, Li said.\u003C\/p\u003E\u003Cp\u003EThe researchers used a statistical method known as the Cox-Hazard analysis, performed by bioengineering graduate student Nathan Hotaling. The analysis is commonly used by doctors to determine if drugs are safe for a patient. Using this analysis in a prototype benchtop diagnostic device is a unique approach and showed that, statistically, the research findings were significant.\u003C\/p\u003E\u003Cp\u003E\u201cThese microfluidic devices are so cheap and require so little blood that it could become possible for someone to use this in a disposable, rapid way,\u201d said Forest.\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EThis research is supported by the American Heart Association (10GRNT4430029), a Wallace H. Coulter Foundation Translational Grant and by a fellowship from the Technological Innovation Generating Economic Results (TI:GER) program at Georgia Tech. Any conclusions or opinions are those of the authors and do not necessarily represent the official views of the sponsoring agencies.\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ECITATION:\u003C\/strong\u003E Melissa Li, et al., \u201cMicrofluidic Thrombosis under Multiple Shear Rates and Antiplatelet Therapy Doses,\u201d (\u003Cem\u003EPLOS ONE\u003C\/em\u003E, January 2014). (\u003Ca href=\u0022http:\/\/dx.doi.org\/10.1371\/journal.pone.0082493\u0022\u003Ehttp:\/\/dx.doi.org\/10.1371\/journal.pone.0082493\u003C\/a\u003E).\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EResearch News\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EGeorgia Institute of Technology\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003E177 North Avenue\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EAtlanta, Georgia 30332-0181 USA\u003C\/strong\u003E\u003Cbr \/\u003E\u003Ca href=\u0022https:\/\/twitter.com\/GTResearchNews\u0022\u003E\u003Cstrong\u003E@GTResearchNews\u003C\/strong\u003E\u003C\/a\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts:\u003C\/strong\u003E Brett Israel (\u003Ca href=\u0022https:\/\/twitter.com\/btiatl\u0022\u003E@btiatl\u003C\/a\u003E) (404-385-1933) (\u003Ca href=\u0022mailto:brett.israel@comm.gatech.edu\u0022\u003Ebrett.israel@comm.gatech.edu\u003C\/a\u003E) or John Toon (404-894-6986) (\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E)\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EWriter:\u003C\/strong\u003E Brett Israel\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EA new microfluidic method for evaluating drugs commonly used for preventing heart attacks has found that while aspirin can prevent dangerous blood clots in some at-risk patients, it may not be effective in all patients with narrowed arteries. The study, which involved 14 human subjects, used a device that simulated blood flowing through narrowed coronary arteries to assess effects of anti-clotting drugs.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"A new microfluidic method for evaluating drugs commonly used for preventing heart attacks has found that while aspirin can prevent dangerous blood clots in some at-risk patients, it may not be effective in all patients with narrowed arteries."}],"uid":"27902","created_gmt":"2014-03-24 09:42:24","changed_gmt":"2016-10-08 03:16:07","author":"Brett Israel","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2014-03-24T00:00:00-04:00","iso_date":"2014-03-24T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"284961":{"id":"284961","type":"image","title":"Craig Forest with microfluidic chip","body":null,"created":"1449244216","gmt_created":"2015-12-04 15:50:16","changed":"1475894978","gmt_changed":"2016-10-08 02:49:38","alt":"Craig Forest with microfluidic chip","file":{"fid":"199019","name":"forest-chip1.jpg","image_path":"\/sites\/default\/files\/images\/forest-chip1_0.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/forest-chip1_0.jpg","mime":"image\/jpeg","size":188234,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/forest-chip1_0.jpg?itok=OhsmyrEO"}},"284951":{"id":"284951","type":"image","title":"Artificial blood vessels on a microfluidic chip","body":null,"created":"1449244216","gmt_created":"2015-12-04 15:50:16","changed":"1475894978","gmt_changed":"2016-10-08 02:49:38","alt":"Artificial blood vessels on a microfluidic chip","file":{"fid":"199018","name":"microfluidic-chip1.jpg","image_path":"\/sites\/default\/files\/images\/microfluidic-chip1_0.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/microfluidic-chip1_0.jpg","mime":"image\/jpeg","size":379441,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/microfluidic-chip1_0.jpg?itok=cqFZgm3k"}}},"media_ids":["284961","284951"],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"146","name":"Life Sciences and Biology"}],"keywords":[{"id":"89811","name":"aspirin"},{"id":"7270","name":"atherosclerosis"},{"id":"12333","name":"Craig Forest"},{"id":"11881","name":"David Ku"},{"id":"12427","name":"microfluidics"},{"id":"7229","name":"thrombosis"}],"core_research_areas":[{"id":"39441","name":"Bioengineering and Bioscience"}],"news_room_topics":[{"id":"71891","name":"Health and Medicine"}],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EBrett Israel\u003C\/p\u003E\u003Cp\u003E404-385-1933\u003C\/p\u003E\u003Cp\u003E\u003Ca href=\u0022mailto:brett.israel@comm.gatech.edu\u0022\u003Ebrett.israel@comm.gatech.edu\u003C\/a\u003E\u003C\/p\u003E","format":"limited_html"}],"email":["brett.israel@comm.gatech.edu"],"slides":[],"orientation":[],"userdata":""}}}