FDA approves Abbott’s fully dissolving heart stent

Abbott announced that the U.S. Food and Drug Administration has approved the company’s Absorb bioresorbable heart stent, making the first-of-its-kind medical device commercially available to treat people with coronary artery disease in the United States.

Absorb is the only fully dissolving stent approved for the treatment of coronary artery disease, which affects 15 million people in the United States and remains a leading cause of death worldwide, despite decades of therapeutic advances. While stents are traditionally made of metal, Abbott’s Absorb stent is made of a naturally dissolving material, similar to dissolving sutures. Absorb disappears completely1 in approximately three years, after it has done its job of keeping a clogged artery open and promoting healing of the treated artery segment. By contrast, metal stents are permanent implants that restrict vessel motion for the life of the person treated.

“The Absorb bioresorbable scaffold represents a major advance in the treatment of coronary artery disease,” said Gregg W. Stone, M.D., FACC, FSCAI, director, cardiovascular research and education, Center for Interventional Vascular Therapy, Columbia University Medical Center, New York-Presbyterian Hospital and the chairman of the ABSORB clinical trial program. “This novel technology appeals to both physicians and patients alike because after treating the underlying blockage it is completely absorbed, leaving nothing behind. No metal means the treated artery can pulse and flex naturally as demands on the heart change with everyday activities. No metal may also reduce the potential of future blockages that occur with permanent metallic stents, and allows easier access to other treatment options should they prove necessary in the patient’s future.”

Abbott plans to offer the Absorb device to hospitals in the United States, starting with interventional cardiology centers that participated in Absorb clinical trials.

“Abbott’s goal is to help people everywhere live better, fuller and healthier lives,” said Deepak Nath, Ph.D., senior vice president, vascular, Abbott. “The Absorb bioresorbable stent treats coronary artery disease without committing people to a permanent metal implant—giving them peace of mind and helping them get back to their daily lives without the concern of having a permanent metallic implant. We’re very excited to bring the promise of Absorb to patients in the United States.”

In clinical studies conducted around the world, the Absorb bioresorbable stent demonstrated comparable short-term and mid-term outcomes to the leading metallic stent—Abbott’s Xience™ drug eluting stent. At one year in a pre-specified group of approximately 2,000 U.S. patients in the pivotal ABSORB III randomized clinical trial, patients who received the dissolving Absorb stent experienced comparable rates of specific adverse events in the intended patient population (reference vessel diameter of ≥ 2.5 mm and ≤ 3.75 mm)—including heart disease-related death, heart attacks attributed to the stented artery and repeat procedures at the treated lesion (collectively termed target lesion failure)—as compared to patients who received the metallic Xience stent.

Abbott’s Absorb stent, sold commercially as the Absorb GT1 Bioresorbable Vascular Scaffold (BVS) system, is now available in more than 100 countries, including the United States, and has been used to treat more than 150,0002 people with coronary artery disease worldwide.

A press release can be found from Abbott website.

Low cost portable Zika test

University of Pennsylvania engineers have developed a rapid, low-cost genetic test for the Zika virus. The $2 testing device, about the size of a soda can, does not require electricity or technical expertise to use. A patient would simply provide a saliva sample. Color-changing dye turns blue when the genetic assay detects the presence of the virus.

Rapid, accurate diagnosis is especially important for pregnant women who may be infected. However, the only approved tests for the virus currently require highly sensitive laboratory equipment. Diagnostic tools that can be used in the field, while the patient waits, would be a critical tool for fighting the Zika epidemic.

The engineers demonstrated the design and efficacy of their test in a study published in the journal Analytical Chemistry. It was conducted by Research Assistant Professor Changchun Liu and Professor Haim Bau of the Department of Mechanical Engineering and Applied Mechanics in Penn’s School of Engineering and Applied Science, along with members of the Bau lab, Jinzhao Song and Michael Mauk. They collaborated with Sara Cherry, associate professor of microbiology in Penn’s Perelman School of Medicine, and Brent Hackett, a member of her lab.

Assays that detect genetic material from the Zika virus itself are considered the gold standard in diagnostics. Alternatives, such as tests that look for antibodies the body creates in response to the virus, are insufficient as they may produce false negatives from people who are infected but haven’t yet produced enough antibodies, or false positives from people who have antibodies for a different disease that is similar enough to trigger the test.

Tests that look for RNA sequences from the virus itself, known as reverse transcriptase polymerase chain reaction, or RT-PCR, avoid both problems. However, RT-PCR requires delicate laboratory work. Viral gene sequences in a patient’s sample must be amplified, or repeatedly copied, to levels where they can be detected, a process that normally involves multiple precise temperature changes.

“The CDC has approved, on an emergency basis, only these kinds of laboratory-based molecular tests for the Zika virus,” said Liu. “Generally, lateral flow tests, which directly change the color of a test strip based on the presence of Zika antibodies, suffer from low sensitivity. And since antibodies to the Zika virus cross-react with other similar viruses prevalent in Zika-endemic areas, lateral flow tests for Zika also suffer from low specificity.”

With the amplification step as the main hurdle to a portable genetic test, the Penn researchers investigated the possibility of using an alternative technique known as RT-LAMP, or reverse transcription loop-mediated isothermal amplification, which only requires the sample to be kept at a specific temperature, not cycled through multiple precise temperature changes as in RT-PCR.

As a trade-off for this simplified amplification process, RT-LAMP requires even more specialized “primers,” short gene sequences that are designed to match the regions of the virus’ DNA targeted by the test.

“Although Zika primers for RT-PCR have been published in the literature, RT-LAMP primers have not,” Bau said. “So, using data mining, we identified highly conserved regions of the Zika virus genome that are divergent from other known pathogens. We then designed appropriate primers to recognize this sequence.

“In parallel,” Liu said, “we engineered a low-cost, point-of-care system that consists of a diagnostic cassette and a processor. The cassette isolates, concentrates and purifies nucleic acids and carries out enzymatic amplification. The test results are indicated by the change in the color of a dye, which can be inspected visually.”

The researchers then worked on how to keep the sample at the necessary temperature without using electricity. Their solution involved a thermos bottle, a self-contained heating element that uses a chemical reaction from portable military rations and a wax-like material that absorbs excess heat by melting. A 3-D printed lid fits on top of the thermos and holds all of the test’s components in place.

Once a patient’s saliva sample is introduced into the cartridge, the test takes about 40 minutes to run. The researchers demonstrated its efficacy with their own saliva spiked with virus samples generated by the Cherry Lab, showing sensitivity equivalent to that of RT-PCR tests. Future work will demonstrate the test’s selectivity and will also test a version that can quantify the viral load by means of a fluorescent dye and an integrated smartphone camera.

“Our work represents a proof of concept at this stage,” Bau said. “Before the assay can be adapted for medical use, we must experiment with patients’ samples and make assure that our assay and system match the performance of the gold standard and operate reproducibly and reliably. We are fortunate to have dedicated colleagues in endemic regions ready to assist us in this task.”

The work was supported, in part, by National Institutes of Health grants K25AI099160 and R21.AI.112713.0 and Penn Center for AIDS Research Pilot Grant AI045008.

Liu and Bau were the recipients of Penn’s 2015 One Health Award for their work on point-of-care molecular diagnostics.

Full story can be found from University of Pennsylvania website.

A tiny pump comes to the aid of weakened hearts

École polytechnique fédérale de Lausanne (EPFL) researchers have developed an innovative cardiac support system in the form of a small ring placed on the aorta. This device is less invasive than traditional methods and avoids problems of hemolysis and the need for regular transfusions because it does not come into direct contact with the blood.

The heart is sometimes in a weakened state when recovering from certain diseases or while waiting for a transplant. To help the tired heart pump blood, researchers at EPFL’s Integrated Actuators Laboratory (LAI) came up with a clever solution. Their device is made up of three tiny rings made out of a material with special electrical properties. The device, called a Dielectric Electro Active polymer (DEAP), dilates when a current is applied and contracts when it is switched off. Because the reactions are immediate, the back-and-forth movement can be controlled in real time.

The researchers’ innovation was to place these rings around the aorta – the body’s main artery – at the exact spot where it exits the left ventricle. Each ring has two electrodes that are drawn together by an electrostatic force whenever the electric field is activated. “The electrodes squeeze the polymer as they come together,” said Jonathan Chavanne, a PhD student at the LAI. “Yet because this material is incompressible, its volume remains constant. So its surface area increases and stores up elastic energy.”

The electrical pulse is provided to the device by magnetic induction. Each of the three rings contracts in turn, in a movement reminiscent of an earthworm. This series of contractions, called peristalsis, creates a wave that moves the liquid inside the artery. This double action – simultaneously vertical and horizontal – helps the heart pump and transport blood.

“This method does not require us to enter the heart,” said Yves Perriard, the director of the LAI. “This means it is significantly less invasive than other cardiac support systems, which work by implanting valves or screw pumps inside the ventricle.”

In addition, by avoiding direct contact with the blood, this new solution eliminates the risk of excessive hemolysis, in which enough red blood cells are destroyed that regular transfusions may be required. And because the system is powered by magnetic induction, there are no wires coming out of the body.

The invention is currently in the prototype stage and has several more hurdles to overcome. The researchers plan to improve the device’s performance before testing it on a liquid with similar fluidic properties to those of the blood, such as glycerol. The team has been in contact with the University Hospital of Bern, where clinical trials could be conducted.

Details can be found from EPFL website.

Wearable noninvasive and continuous hemoglobin concentration monitor FDA approved

Masimo announced FDA 510(k) clearance for Radius-7® – the first and only wearable, tetherless, noninvasive rainbow® monitor. Radius-7, which connects to the Root® patient monitoring and connectivity platform, is now available in the U.S. with breakthrough Masimo rainbow® technology. With this clearance, Radius-7 with Root now enables noninvasive monitoring of more than 10 parameters, including, for the first time in a wearable device, total hemoglobin (SpHb®), a breakthrough measurement that noninvasively and continuously measures hemoglobin concentration.

SpHb monitoring may provide additional insight to the directional trend of hemoglobin between invasive blood samplings – when the SpHb trend is stable and the clinician may otherwise think hemoglobin is decreasing; when SpHb trend is rising and the clinician may otherwise think hemoglobin is not rising fast enough; or when the SpHb trend is decreasing and the clinician may otherwise think hemoglobin is stable. SpHb may thus help clinicians make more timely and informed decisions, and has been shown to help clinicians provide more timely blood transfusions* and reduce blood transfusions in cases such as neurosurgery and orthopedic surgery.1,2

Professor Christer Svensen, Professor of Anesthesiology and Intensive Care at the Karolinska Institute in Stockholm, Sweden, who has been using Radius-7 as part of a research study, commented, “We are currently performing a noninvasive continuous study monitoring respiratory rate, heart rate and saturation for all patients admitted to a surgical ward. Additionally, we are monitoring SpHb for selected postsurgical patients, which can be extremely beneficial because it can provide insight into hemoglobin trends between invasive blood samplings. Such insight may lead clinicians to confirm trends by performing blood draws sooner than they might otherwise have done, which may then suggest the need to intervene.”

For the first time, it is possible to offer patients freedom of movement while providing such important monitoring, and studies have shown that patient mobility is a key factor in more rapid patient recovery.3,4 When monitoring ambulating patients, Radius-7 communicates to Root at the bedside and thereby to Masimo Patient SafetyNet™ to alert clinicians of critical changes in oxygen saturation, pulse rate, respiration, and hemoglobin, among other parameters. Radius-7 is lightweight, weighing only 0.34 lbs, and attaches to the arm, thus allowing untethered monitoring whether a patient is in or out of bed – which also reduces the need for nursing assistance, as there is no need to disconnect from or reconnect to a bedside monitor. Each Radius-7 comes with two “hot-swappable” rechargeable battery modules (one with the patient, one charging), each with a battery life of 12 hours, minimizing monitoring interruption.

“Never before could patients be monitored for such key parameters as continuous SpHb, which can help clinicians make more timely and informed blood management decisions, while patients are fully mobile. Previous wearable patient monitors were hampered by a limited range of measurements and false alarms due to motion,” said Joe Kiani, Founder and CEO of Masimo. “Root with Radius-7 with rainbow SET, coupled with Patient SafetyNet for mobile clinician notification, is now an even more versatile and powerful monitoring system, all while promoting freedom of patient movement and quicker recovery times.”

Details can be found from Masimo website by following this link.

The First Minimally Invasive Heart Failure Treatment to Restore the Left Ventricle CE Approved

BioVentrix Inc announced that it has received certification for CE marking its Revivent TC™ TransCatheter Ventricular Enhancement System. Following a myocardial infarction or heart attack, the Revivent TC™ System implants proprietary micro-anchor pairs to exclude scarred myocardium from the healthy tissue of the left ventricle (LV). The restoration of the LV to a more optimal volume and conical shape has proven to enhance cardiac performance and significantly improve a patient’s quality of life.

“The certification for CE marking is not only an important milestone for the company, but also for those who treat heart failure,” said Mr. Kenneth Miller, President and Chief Executive Officer of BioVentrix. “More importantly, it transforms the spectrum of treatment by offering a minimally invasive therapeutic solution for the previously ignored ventricle. By making this critical treatment available, we are giving physicians an important additional resource that they can utilize in conjunction with existing valvular and vascular therapies, making Guideline-Directed Medical Therapy (GDMT) even more effective. Moreover, it provides access to efficacious and tolerable therapy to many frail patients who previously would have no options,” continued Mr. Miller. “More than 100,000 patients will become eligible each year for this device implant,” said Mr. Miller.

“Heart failure remains an epidemic worldwide and the CE marking certification validates the need for a novel therapy for heart failure patients suffering from left ventricular dysfunction,” added Dr. Lon Annest, Chief Medical Officer of BioVentrix. “There is no doubt that LV volume reduction is an important therapy as it directly impacts the parameters that determine prognosis and survival, such as LV volume and ejection fraction. The impact of the Revivent TC System is achieved by transcatheter access to exclude the ischemic portion of the left ventricle from the healthy tissue,” continued Dr. Annest. “This empowers heart teams in Europe, who currently have a backlog of patients, and soon, in the US, to ensure optimal clinical outcomes by minimizing the risk compared to conventional surgery,” said Dr. Annest.

At 2-year follow-up, patients have made remarkable improvements in their Quality of Life by 38%. Additionally, the clinical benefit has been proven to extend life for patients with a significant reduction of LV end-systolic volume index (31%) and improvement of LV ejection fraction (23%)2. Left ventricular volume reduction is especially critical for the survival of a patient as other studies have shown that significant LV volume reduction can directly prolong a patient’s life1. The Revivent TC System is the only interventional therapy that can consistently achieve this survival benefit in heart failure patients.

More information can be found from Bio Ventrix website.

Self-assembling protein icosahedral shell designed

The same 20-sided solid that was morphed into geodesic domes in the past century may be the shape of things to come in synthetic biology.

For University of Washington Institute of Protein Design scientists working to invent molecular tools, vehicles, and devices for medicine and other fields, the icosahedron’s geometry is inspiring. Its bird cage-like symmetry and spacious interior suggest cargo-containing possibilities.

The protein designers took their cue from the many viruses that, en route to living cells, transport their genomes inside protective icosahedral protein shells. These delivery packages, termed viral capsids, are formed to be tough enough to withstand the trip, efficiently use storage room, and break apart to release their contents when conditions are right.

The researchers’ paper in the scientific journal Nature reports on their computational design and experimental testing of a highly stable icosahedral protein nano-cage. Engineered at the atomic level, this nano-cage can construct itself from biochemical building blocks and information encoded in strands of DNA.

After selecting the design for this icosahedral nano-cage through computer modeling, the researchers produced it in bacteria. Electron microscopy of the resulting icosahedral particles confirmed that they were nearly identical to the design model.

The leads on the project were Yang Hsia, a University of Washington graduate student in biological physics, structure and design, and Jacob B. Bale, a recent graduate from the UW molecular and cellular biology Ph.D. program, and now a research scientist at Arzeda Corporation in Seattle. The senior authors were Neil P. King, translational investigator at the UW Institute for Protein Design, and David Baker, director of the Institute and UW professor of biochemistry. Baker is also an investigator with the Howard Hughes Medical Institute.

“The ability to design proteins that self-assemble into precisely specified, robust, and highly order icosahedral structures,” the researchers wrote, “would open the door to a new generation of protein containers with properties custom-made for applications of interest.”

Among these applications might be fabricating nanoscale icosahedral vehicles. Such research might create tiny, spacecraft-like devices that could encapsulate and deliver therapies directly to specific types of cells, such as cancer cells.

The designed icosahedron, while sturdy, proved to disassemble and reassemble itself under certain environmental conditions. This reversible property is essential if it eventually becomes part of packaging, carrying and delivering a biochemical payload.

In addition, the flexibility to modify these miniature cages, the researchers said, “should have considerable utility for targeted drug delivery, vaccine design and synthetic biology.”

The newly designed icosahedron has considerably larger internal volume than previously designed nano-cages of other shapes, and so could hold more cargo as molecular shipping containers.

Working towards that end, the researchers were able to design barriers for the center of each of the twenty faces of the icosahedron. These could block molecules from entering and leaving the cage. In future iterations, gated cages might be filled to carry a medication into particular kinds of cell and then discharge it.

Moreover, the protein building blocks making up the cage retain their natural enzymatic activity, which is the ability to speed up chemical reactions. This suggests the possibility of custom designing them as nano-reactors to catalyze specific biochemical processes.

The nano-cages were, in addition, amenable to genetic fusions to enhance their properties. For example, the researchers created standard candles for light microscopy by adding a fluorescent protein to each of the 60 subunits that frame the icosahedron. The fluorescent intensity was proportional to the number of these proteins attached to each subunit. The distinctive shape of the icosahedron makes it a readily spotted marker.

This project was supported by the Howard Hughes Medical Institute, the JRC Visitor Program, the National Science Foundation, a University of Washington/Fred Hutchinson Cancer Research Institute Pilot Award from the National Cancer Institute, the Takeda Pharmaceutical Company, the Bill & Melinda Gates Foundation, the National Institutes of Health, and a Public Health Services National Research Services Award.

More information can be found from University of Washington website.