Imaging can be a cost-effective way to identify people at risk for stroke who might benefit from aggressive intervention, according to a new modeling study published online in the journal Radiology.
The study looked at people with asymptomatic carotid artery stenosis, a narrowing of the major blood vessels supplying blood to the head due to atherosclerosis, or plaque buildup. Carotid artery stenosis is the primary cause of up to 20 percent of ischemic strokes, which result from an obstruction within a blood vessel and make up 85 percent of all strokes.
This is a graph of two-way sensitivity analysis shows optimal strategy for different combinations of baseline stroke risk and probability of complications during revascularization. CVR strategy is optimal in the blue region, which includes base-case result (marked by an x); other strategies could be optimal given other combinations of stroke risk and revascularization complication risks.
Credit: Radiological Society of North America
Stroke victims often undergo revascularization procedures like carotid endarterectomy, or surgical removal of the plaque, to restore blood flow, but use of the procedures in asymptomatic patients is more controversial, according to Ankur Pandya, Ph.D., assistant professor of healthcare policy and research and public health in radiology at Weill Cornell Medical College in New York City.
"There are complications and costs associated with these revascularization procedures, and they are often done without knowing if the risks and costs are worth the benefits," Dr. Pandya said.
Dr. Pandya and colleagues recently assessed the impact of cerebrovascular reserve (CVR) testing, a measure of blood flow reserve to the brain, on asymptomatic people with significant carotid artery stenosis. While different imaging modalities can be used in CVR testing, the researchers used transcranial Doppler (TCD) sonography, an inexpensive, widely available option that does not expose patients to ionizing radiation.
They constructed a mathematical model that allowed them to make hypothetical comparisons among three different approaches: CVR testing, immediate revascularization with carotid endarterectomy, and medical therapy-based management with subsequent revascularization only for patients whose stenosis got worse.
The CVR-based approach, which led to about half of the patients receiving revascularization, appeared to have the most favorable balance of benefits and costs. The medical therapy-based strategy was associated with the lowest lifetime costs and the fewest revascularizations; however, it also resulted in the lowest life expectancy and lifetime quality-adjusted years, which account for both the length and quality of life experienced by patients. The immediate revascularization strategy had the highest costs, by a wide margin, and only incremental health benefits compared with the CVR-based approach.
"The study results show that imaging can be a cost-effective tool to stratify patients by risk of stroke and help sort patients into invasive, expensive interventions and less invasive options," Dr. Pandya said.
Dr. Pandya said that CVR testing also has the potential to help characterize whether carotid artery plaque is causing abnormal brain blood flow patterns which may, therefore, identify the patients who are at greatest risk of stroke.
"CVR testing with ultrasound could be used to stratify patients by risk based on abnormal blood flow patterns to the brain, and then other imaging tests like MRI could be employed to look at the composition and stability of plaque, which may give greater insight into those plaques most likely to rupture and cause symptoms" Dr. Pandya said.
Cost-effectiveness models like the one used in the study have gained prominence is recent years and are already used by healthcare payers in Europe, Canada and Australia. Dr. Pandya expects these models to become more prominent in the United States as healthcare reform evolves.
"Our model takes all these pieces of information on risks, costs and benefits and does the math in a systematic way to help clinicians make decisions," he said.
An estimated 400,000 patients over the age of 70 years in the United States have asymptomatic carotid artery stenosis, putting them at a higher risk of stroke.
"Carotid Artery Stenosis: Cost-effectiveness of Assessment of Cerebrovascular Reserve to Guide Treatment of Asymptomatic Patients." Collaborating with Dr. Pandya at Weill Cornell Medical College were Ajay Gupta, M.D., Hooman Kamel, M.D., Babak B. Navi, M.D., Pina C. Sanelli, M.D., M.P.H., and Bruce R. Schackman, Ph.D.
Radiology is edited by Herbert Y. Kressel, M.D., Harvard Medical School, Boston, Mass., and owned and published by the Radiological Society of North America, Inc.
RSNA is an association of more than 53,000 radiologists, radiation oncologists, medical physicists and related scientists promoting excellence in patient care and health care delivery through education, research and technologic innovation. The Society is based in Oak Brook, Ill. (RSNA.org)
For patient-friendly information on stroke, visit RadiologyInfo.org.
Linda Brooks | Eurek Alert!
3-D visualization of the pancreas -- new tool in diabetes research
15.03.2017 | Umea University
New PET radiotracer identifies inflammation in life-threatening atherosclerosis
02.03.2017 | Society of Nuclear Medicine
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy