Medtronic recalls implantable infusion pumps due to software problem

Photo: Medtronic

According to FDA Recall Notice, Medtronic is recalling the SynchroMed Implantable Infusion Pumps because a software problem may cause unintended delivery of drugs during a priming bolus procedure, used to quickly deliver large dose of medication from the device to the patient’s spine. During this procedure, patients may receive the drug unintentionally at a high rate of infusion in the cerebrospinal fluid followed by a period of reduced drug delivery after the priming bolus. This can result in a drug overdose or under dose which can lead to serious adverse health consequences such as respiratory depression, coma or death.

The SynchroMed II and SynchroMed EL Implantable Drug Infusion Pumps (SynchroMed Implantable Infusion Pumps) are programed to deliver prescribed drugs to a specific site inside the patient’s body. The SynchroMed pumps are used to treat primary or metastatic cancer, chronic pain, and severe spasticity.

3D Printing Customized Vascular Stents

Northwestern Engineering’s Guillermo Ameer and Cheng Sun have teamed up to use 3-D printing to develop flexible, biodegradable stents that are customized for a specific patient’s body.

“Right now, the vast majority of stents are made from a metal and have off-the-shelf availability in various sizes,” said Ameer, professor of biomedical engineering in Northwestern’s McCormick School of Engineering and professor of surgery in the Feinberg School of Medicine. “The physician has to guess which stent size is a good fit to keep the blood vessel open. But we’re all different and results are highly dependent on physician experience, so that’s not an optimal solution.”

Supported by the American Heart Association, the research is published online in the journal Advanced Materials Technologies. Robert van Lith, a postdoctoral fellow in Ameer’s laboratory, and Evan Baker, a graduate student in Sun’s laboratory, are co-first authors of the paper.

When ill-fitting stents move in the artery, they can ultimately fail. In these cases, physicians have to somehow re-open the blocked stent or bypass it with a vascular graft. It’s a costly and risky process.

“There are cases where a physician tries to stent a patient’s blood vessel, and the fit is not good,” Ameer said. “There might be geometric constraints in the patient’s vessel, such as a significant curvature that can disturb blood flow, causing traditional stents to fail. This is especially a problem for patients who have conditions that prevent the use of blood thinners, which are commonly given to patients who have stents. By printing a stent that has the exact geometric and biologic requirements of the patient’s blood vessel, we expect to minimize the probability of these complications.”

To create these customized stents, Ameer worked with Sun to adapt a 3-D printing technique, called projection micro-stereo-lithography, to fabricate stents using a polymer previously developed in Ameer’s lab. The technique uses a liquid photo-curable resin or polymer to print objects with light. When a pattern of light is shined on the polymer, it converts it into a solid that is then slowly displaced to cure the next layer of liquid polymer. The printing technology allows the team to fabricate a stent that precisely matches desirable design characteristics.

Sun’s 3-D printing technique, known as micro continuous liquid interface production (microCLIP), has several advantages. First, it is extremely high resolution. With the ability to print features as small as 7 microns, it is perfect for printing stents, which have very fine mesh dimensions and can be smaller than 3 millimeters in diameter. Second, it has the ability to print up to 100 stents at a time, producing them faster and potentially cheaper than traditional manufacturing methods. Third, it’s fast, printing a 4-centimeter stent in a matter of minutes.

Although current stents are made with metal wire mesh, Ameer used a citric-acid based polymer previously developed in his lab. The resulting stent is flexible, biodegradable, and has inherent antioxidant properties. Drugs can also be loaded onto the polymer and slowly released at the implantation site to improve the healing process in the blood vessel wall. Ameer has previously shown that the polymer can be engineered to inhibit clot formation when applied to vascular grafts. The stent is strong and biodegradable, allowing it to exercise its mechanical function during the vessel’s initial dilation and slowly dissolve as the re-opened blood vessel recovers.

“In theory, it’s safer because the patient doesn’t have permanent foreign metal devices in the body,” Ameer said. “If, for any reason in the future, the surgeon needs to go back in to that location in the vessel, they can. There’s not a metal stent in the way.”

Current biodegradable stents are made from plastics similar to those used for sutures. They are not as strong as wire mesh and can take longer than metal stents to fully expand when deployed. To compensate for this weakness, the plastic stents are strengthened by increasing the thickness of their struts relative to that of a metal stent. Ameer’s 3-D printed stent, however, can be fabricated with the thinner profile of traditional metal wire stents, so it is more compatible with the body.

Ameer and Sun, associate professor of mechanical engineering, imagine a future process whereby the dimensions of a patient’s vessel are obtained using standard imaging techniques available at hospitals, and a stent is then printed on site to exactly fit the vessel’s dimensions, packaged, and given to the surgeon for implantation. Next, Ameer plans to investigate how long it takes for his biodegradable stent to break down and absorb into the body. His team also aims to investigate innovative stent designs to improve their long-term performance.

“Not only can we customize the stent for a patient’s blood vessels,” he said, “but we can create all new types of patient-specific medical devices that could make the outcomes of surgical procedures better than what they are today.”

Source: Northwestern University

Draper’s first neural interface in humans

Draper engineers are rapidly moving toward realizing the technology that can provide a natural sense of feeling and proprioception—the ability to process and integrate limb orientation information—to patients who have lost a limb. The implantable device can ultimately allow those with a prosthetic limb a much more intuitive, controlled user experience with their prosthetic and an improved interaction with the world around them.
This research is funded by the Defense Advanced Research Projects Agency’s (DARPA) Hand Proprioception and Touch Interfaces (HAPTIX) program. The University of Texas Southwestern (UTSW) conducted successful testing, on behalf of Draper, of the novel electrode component in animal studies. Next, they will be tested in humans as early as the fall of 2016 as part of a follow-on Phase II contract DARPA awarded Draper in April.
The electrodes of Draper’s HAPTIX system deliver electrical signals to nerves in the forearm, much the same way the human nervous system does, creating an artificial sensory feedback. Draper’s approach is unique in that the electrodes wrap around as well as directly interact with the nerves, thus allowing for more precise stimulation and a more real sense of touch for amputees. “Draper makes inherently safe systems that work, whether we’re designing an active implantable medical device or a fault-tolerant computer system for space missions,” said Dr. Philip Parks, Draper’s HAPTIX program manager.
Full story is available from Draper website.

Boston Scientific Receives CE Mark For LOTUS Edge Valve System

Boston Scientific has received CE Mark for the LOTUS Edge™ Valve System, the company’s next generation transcatheter aortic valve implantation (TAVI) technology. The LOTUS Edge valve system is indicated for aortic valve replacement in patients with severe aortic stenosis who are considered at high risk for surgical valve replacement. Instead of open heart surgery, the replacement valve is delivered via transcatheter percutaneous delivery, a minimally invasive procedure involving a small incision to gain access to a blood vessel.

In comparison to the Lotus™ Valve System, this next iteration incorporates a more flexible, lower profile catheter designed to improve ease of use and accommodate tortuous anatomy. Another differentiating feature of the LOTUS Edge valve system is the inclusion of Depth Guard™, a design element intended to reduce the need for a permanent pacemaker (PPM).

A press release is available from Boston Scientific website.

Wireless connectivity for implanted devices

University of Washington researchers have introduced a new way of communicating that allows devices such as brain implants, contact lenses, credit cards and smaller wearable electronics to talk to everyday devices such as smartphones and watches.

This new “interscatter communication” works by converting Bluetooth signals into Wi-Fi transmissions over the air. Using only reflections, an interscatter device such as a smart contact lens converts Bluetooth signals from a smartwatch, for example, into Wi-Fi transmissions that can be picked up by a Smartphone.

“Wireless connectivity for implanted devices can transform how we manage chronic diseases,” said co-author Vikram Iyer, a UW electrical engineering doctoral student. “For example, a contact lens could monitor a diabetic’s blood sugar level in tears and send notifications to the phone when the blood sugar level goes down.”

Due to their size and location within the body, these smart contact lenses are too constrained by power demands to send data using conventional wireless transmissions. That means they so far have not been able to send data using Wi-Fi to smartphones and other mobile devices.

Those same requirements also limit emerging technologies such as brain implants that treat Parkinson’s disease, stimulate organs and may one day even reanimate limbs.

Full story can be found from University of Washington website.


ReliantHeart’s aVAD Gets CE Mark

ReliantHeart’s next-generation aVAD left ventricular assist device has just earned CE Mark approval and implants are set to begin in September.

The LVAD market is going through an evolution right now as major commercial players Thoratec and HeartWare have both been acquired by large medtech companies. Thoratec was acquired by St. Jude Medical last year; St. Jude Medical has since been purchased by Abbott ($ABT). Medtronic ($MDT) announced its acquisition of HeartWare in June.

Manufacturing of the aVAD is underway and 65 units are scheduled to be shipped in September and October, with 100 pumps expected to be available by year end, according to Ford. Pricing for the aVAD is expected to be equivalent to Thoratec’s HeartMate 3 LVAD.

Implants are set to start in Europe in September, with plans for a controlled launch at centers in Germany, Turkey, and London first. Up to 50 patients will be implanted and Ford said data will be collected at several timepoints after the procedure, including one, seven, 30, 90, and 160 days, or at the time of any adverse event. Some of the centers that will be part of the controlled launch are already familiar with ReliantHeart’s HeartAssist5 LVAD, which has had CE Mark since 2013.

Surgeons will be able to implant the aVAD using the surgical approach of their choice, including a sternotomy or a left thoracotomy. “It’s going to be dealer’s choice,” Ford said. “Why limit it? Some of these [surgeons] are really good at left thoracotomies. Let them do it.”

The novel features aVAD offers may mean some surgeons need training to optimize its capabilities. Ford explained that because other LVADs have a calculated flow measurement, as opposed to the flow sensor aVAD uses, “the first thing [physicians] need to do is trust the flow.” In addition, clinicians will need to gain experience with remote monitoring. Physicians will need to “set the alarms properly so that the thresholds for low flow or high power provide an advance warning of something that could be a bad outcome,” Ford said.

ReliantHeart was able to attain CE Mark for aVAD without a trial because the pump’s blood path is the same as the company’s HeartAssist 5 LVAD, which already has CE Mark. “We’ve made this really powerful new pump but the blood path is exactly the same,” Ford said.

An FDA animal trial is scheduled to begin this month and ReliantHeart is still anticipating a human FDA IDE trial to begin in early 2017. The animal trial is studying the aVAD with a disconnectable cable—a feature that is not yet incorporated into the CE Mark device. Once the aVAD with a disconnectable cable has been studied in animals, it will be substituted into Europe.

That disconnectable cable is important because it is intended to reduce the need for LVAD pump replacements due to driveline infections. It also is a stepping stone to ReliantHeart’s next goal—the Liberty, a wirelessly-powered, fully implantable LVAD that would allow patients to live without being tethered to a battery pack or a cable emerging from their body.

A press release can be found from ReliantHeart website.