Most filters – whether for water or a furnace – eventually need to be removed or replaced to avoid complications.

Blood clot filters, which are implanted in the veins of people at risk of developing blood clots in their legs, require a similar precaution.

Complications have been found to arise when the filters, even those intended to be permanent, are left in longer than three to six months. These complications may include part of the filter breaking off and traveling to the heart and lungs, abdominal pain, filter tilt, and the filter tearing or creating a blockage in the veins of the abdomen (inferior vena cava) or in the legs. The chance of complications increases the longer the filter has been in place. Blood clot filters, also known as inferior vena cava (IVC) filters, potentially are dangerous and require specialized techniques to remove them.

Interventional radiologists at Rush University Medical Center have pioneered methods to remove filters that previously couldn’t be removed for various reasons.

‘We have both the standard retrieval methods as well as the most advanced tools to remove any type of filter, and we have the medical expertise to treat any complications from the filter being implanted,’ says Osman Ahmed, MD, primary author and interventional radiologist at Rush University Medical Center and Rush Oak Park Hospital.

The techniques involve a careful method of catching or ‘snaring’ the filter to hold it in place and then covering it to prevent parts of it breaking free. The team also uses tools such as alligator forceps and excimer laser in removing filters.

Thanks to these methods, the Rush team has achieved a 100 percent retrieval rate over the past five years, including difficult-to-remove filters from patients who have been referred to Rush from other hospitals.

The minimally invasive procedure is performed on an outpatient basis using twilight (conscious) sedation in the interventional radiology suite, which is similar to an operating room but also includes special imaging equipment. More advanced retrievals are performed using general anaesthesia due to the time it may take to remove the filter.

The filter removal is performed through a small incision in the neck or groin (the maximum size is around 5 mm) and the filter is removed using X-ray guidance to manipulate wires, catheters, and other devices necessary to remove the filter, which can be up to 29 mm in length.

The Rush team lead by Bulent Arslan, MD, and Ulku Turba, MD, developed these techniques to remove IVC filters, which are implanted in the inferior vena cava, a large vein just below the kidneys, in order to trap blood clots before they travel to the heart and lungs and cause permanent damage.

Rush University Medical Center www.newswise.com/articles/pioneers-in-ivc-filter-removal

Titanium is the leading material for artificial knee and hip joints because it’s strong, wear-resistant and nontoxic, but an unexpected discovery by Rice University physicists shows that the gold standard for artifi cial joints can be improved with the addition of some actual gold.
‘It is about 3-4 times harder than most steels,’ said Emilia Morosan, the lead scientist on a new study in Science Advances that describes the properties of a 3-to-1 mixture of titanium and gold with a specific atomic structure that imparts hardness. ‘It’s four times harder than pure titanium, which is what’s currently being used in most dental implants and replacement joints.’
Morosan, a physicist who specializes in the design and synthesis of compounds with exotic electronic and magnetic properties, said the new study is ‘a first for me in a number of ways. This compound is not difficult to make, and it’s not a new material.’ In fact, the atomic structure of the material – its atoms are tightly packed in a ‘cubic’ crystalline structure that’s oft en associated with hardness – was previously known. It’s not even clear that Morosan and former graduate student Eteri Svanidze, the study’s lead co-author, were the first to make a pure sample of the ultrahard ‘beta’ form of the compound. But due to a couple of lucky breaks, they and their co-authors are the fi rst to document the material’s remarkable properties.
‘This began from my core research,’ said Morosan, professor of physics and astronomy, of chemistry and of materials science and nano-engineering at Rice. ‘We published a study not long ago on titanium-gold, a 1-to-1 ratio compound that was a magnetic material made from nonmagnetic elements. One of the things that we do when we make a new compound is try to grind it into powder for X-ray purposes. This helps with identifying the composition, the purity, the crystal structure and other structural properties. ‘When we tried to grind up titanium-gold, we couldn’t,’ she recalled. ‘I even bought a diamond (coated) mortar and pestle, and we still couldn’t grind it up.’
What the team didn’t know at the time was that making titanium- 3-gold at relatively high temperature produces an almost pure crystalline form of the beta version of the alloy – the crystal structure that’s four times harder than titanium. At lower temperatures, the atoms tend to arrange in another cubic structure – the alpha form of titanium-3-gold. The alpha structure is about as hard as regular titanium. It appears that labs that had previously measured the hardness of titanium-3-gold had measured samples that largely consisted of the alpha arrangement of atoms.
The team measured the hardness of the beta form of the crystal in conjunction with colleagues at Texas A&M University’s Turbomachinery Laboratory and at the National High Magnetic Field Laboratory at Florida State University; Morosan and Svanidze also performed other comparisons with titanium. For biomedical implants, for example, two key measures are biocompatibility and wear resistance. Because titanium and gold by themselves are among the most biocompatible metals and are oft en used in medical implants, the team believed titanium-3-gold would be comparable. In fact, tests by colleagues at the University of Texas MD Anderson Cancer Center in Houston determined that the new alloy was even more biocompatible than pure titanium. The story proved much the same for wear resistance: Titanium-3-gold also outperformed pure titanium.

Rice University http://tinyurl.com/jto5exc

‘Atrial fibrillation is thought to be responsible for 20 to 30 percent of all strokes in the United States,’ said Northwestern’s Michael Markl, the Lester B. and Frances T. Knight Professor of Cardiac Imaging. ‘While atrial fibrillation is easy to detect and diagnose, it’s not easy to predict who will suffer a stroke because of it.’

Markl, who is a professor of biomedical engineering in the McCormick School of Engineering and of radiology in the Feinberg School of Medicine, has developed a new imaging technique that can help predict who is most at risk for stroke. This breakthrough could lead to better treatment and outcomes for patients with atrial fibrillation.

Atrial fibrillation is linked to stroke because it slows the patient’s blood flow. The slow, sluggish blood flow can lead to blood clots, which can then travel to the brain and initiate stroke. Markl’s cardiac magnetic resonance (CMR) imaging test can detect the blood’s velocity through the heart and body. Called ‘atrial 4D flow CMR,’ the technique is non-invasive and does not require contrast agents. The imaging program, which images blood flow dynamically and in the three spatial dimensions, comes in the form of software that can also be integrated into current MRI equipment without the need of special hardware and scanners or equipment upgrades.

4D flow CMR can be employed to measure in-vivo 3D blood flow dynamics in the heart and atria. Derived flow stasis maps in the left atrium and left atrial appendage are a novel concept to visualize and quantify regions with low flow, known to cause clot formation and risk for stroke.
‘We simply programmed the scanner to generate information differently – in a way that wasn’t previously available,’ Markl said. ‘It allows you to measure flow, diffusion of molecules, and tissue elasticity. You can interrogate the human body in a very detailed manner.’

Historically, physicians have attempted to assess stroke risk in atrial fibrillation patients by using a risk scoring system, which takes risk factors, such as age, general health, and gender, into account. Higher risk patients are then given medicine to prevent blood clots that lead to stroke.

‘It’s very well accepted that these therapies significantly reduce the risk of stroke,’ Markl said. ‘But they also increase risk of bleeding complications. It’s a dilemma that physicians face. They want to reduce one risk without introducing another risk. It’s particularly difficult for younger patients who might be on these medications for a long period of time. Maybe the risk of bleeding is initially small. But after taking medication for 20 or 30 years, it’s more and more likely that they’ll experience complications.’

Markl’s 4D flow imaging technique can give a more precise assessment of who needs the medication, preventing physicians from over treating their patients. In a pilot study with 60 patients and a control group, Markl found that atrial fibrillation patients who would have been considered high risk for stroke by the traditional scoring system in fact had normal blood flow, while patients who were considered lower risk sometimes had the slow blood flow indicative of potential clotting.

‘About 50 or 60 percent of patients who you would consider high risk actually had normal flows,’ Markl said. ‘You could then hypothesize that those 50 percent don’t really need the treatment.’

Northwestern University www.mccormick.northwestern.edu/news/articles/2016/10/imaging-stroke-risk-in-4d.html

Scientists and doctors in recent decades have made vast leaps in the treatment of cardiac problems, particularly since the development in recent years of ‘cardiac patches,’ swaths of engineered tissue that can replace heart muscle damaged during a heart attack.
The Mark Hyman Jr. Professor of Chemistry and chair of the Department of Chemistry and Chemical Biology, Lieber, postdoctoral fellow Xiaochuan Dai, and other co-authors conducted a study that shows the construction of nanoscale electronic scaffolds that can be seeded with cardiac cells to produce a bionic cardiac patch.
‘I think one of the biggest impacts would ultimately be in the area that involves replaced or damaged cardiac tissue with pre-formed tissue patches,’ Lieber said. ‘Rather than simply implanting an engineered patch built on a passive scaffold, our works suggests it will be possible to surgically implant an innervated patch that would now be able to monitor and subtly adjust its performance.’
Once implanted, Lieber said, the bionic patch could act similarly to a pacemaker, delivering electrical shocks to correct arrhythmia. But the possibilities don’t end there.
‘In this study, we’ve shown we can change the frequency and direction of signal propagation,’ he continued. ‘We believe it could be very important for controlling arrhythmia and other cardiac conditions.’
Unlike traditional pacemakers, Lieber said that because its electronic components are integrated throughout the tissue, the bionic patch can detect arrhythmia far sooner and operate at far lower voltages.
‘Even before a person started to go into large-scale arrhythmia that frequently causes irreversible damage or other heart problems, this could detect the early-stage instabilities and intervene sooner,’ he said. ‘It can also continuously monitor the feedback from the tissue and actively respond.’
‘And a normal pacemaker, because it’s on the surface, has to use relatively high voltages,’ Lieber added.
The patch might also find use, Lieber said, as a tool to monitor responses under cardiac drugs, or to help pharmaceutical companies to screen the effectiveness of drugs under development. Likewise, the bionic cardiac patch could also be a unique platform to study the tissue behaviour evolving during some developmental processes, such as aging, ischemia, or differentiation of stem cells into mature cardiac cells.
Although the bionic cardiac patch has not yet been implanted in animals, ‘We are interested in identifying collaborators already investigating cardiac patch implantation to treat myocardial infarction in a rodent model,’ he said. ‘I don’t think it would be difficult to build this into a simpler, easily implantable system.’
In the long term, Lieber believes, the development of nanoscale tissue scaffolds represents a new paradigm for integrating biology with electronics in a virtually seamless way.
Using the injectable electronics technology that he pioneered last year, Lieber even suggested that similar cardiac patches might one day simply be delivered by injection.
‘It may actually be that, in the future, this won’t be done with a surgical patch,’ he said. ‘We could simply do a co-injection of cells with the mesh, and it assembles itself inside the body, so it’s less invasive.’

Harvard University http://tinyurl.com/gp8fdaw

Chemists from Trinity College Dublin, in collaboration with RCSI, have devised a revolutionary new scanning technique that produces extremely high-res 3D images of bones without exposing patients to X-ray radiation.
The chemists attach luminescent compounds to tiny gold structures to form biologically safe nanoagents’ that are attracted to calcium-rich surfaces, which appear when bones crack – even at a micro level. These nanoagents target and highlight the cracks formed in bones, allowing researchers to produce a complete 3D image of the damaged regions.
The technique will have major implications for the health sector as it can be used to diagnose bone strength and provide a detailed blueprint of the extent and precise positioning of any weakness or injury. Additionally, this knowledge should help prevent the need for bone implants in many cases, and act as an early-warning system for people at a high risk of degenerative bone diseases, such as osteoporosis.
The research was led by the Trinity team of Professor of Chemistry, Thorri Gunnlaugsson, and Postdoctoral Researcher, Esther Surender.
Professor Gunnlaugsson said: We have demonstrated that we can achieve a three-dimensional map of bone damage, showing the so-called microcracks, using non-invasive luminescence imaging. The nanoagent we have developed allows us to visualize the nature and the extent of the damage in a manner that wasn’t previously possible. This is a major step forward in our endeavour to develop targeted contrast agents for bone diagnostics for use in clinical applications.’
Professor Lee said: ‘Everyday activity loads our bones and causes microcracks to develop. These are normally repaired by a remodelling process, but, when microcracks develop faster, they can exceed the repair rate and so accumulate and weaken our bones. This occurs in athletes and leads to stress fractures. In elderly people with osteoporosis, microcracks accumulate because repair is compromised and lead to fragility fractures, most commonly in the hip, wrist and spine. Current X ray techniques can tell us about the quantity of bone present but they do not give much information about bone quality.’
He continued: ‘By using our new nanoagent to label microcracks and detecting them with magnetic resonance imaging (MRI), we hope to measure both bone quantity and quality and identify those at greatest risk of fracture and institute appropriate therapy. Diagnosing weak bones before they break should therefore reduce the need for operations and implants – prevention is better than cure.’

Trinity College Dublin http://tinyurl.com/hcvjtd2