Access Vascular, based in Massachusetts, has developed a peripherally inserted central venous catheter (PICC) composed of a thromboresistant hydrogel material. The catheter could reduce the incidence of catheter-related thrombi and resulting adverse events.
When a catheter encounters blood, blood cells and proteins begin to accumulate on its surface. The surface material of the catheter, along with its shape, has a significant effect on the speed and magnitude of this process. Catheter-related thrombi can result in a variety of serious complications, including pulmonary embolism, infections, loss of venous flow, deep vein thrombosis, increased hospital stays, increased patient morbidity and catheter dysfunction.
At present, catheters used for vascular access are made using polyurethanes or silicones. In fact, this design has changed little in decades. These materials provide strength and flexibility, but suffer from thrombogenicity. A variety of coatings and surfaces have been developed to combat this, but often such coatings aren’t durable and thrombus formation can still happen, particularly in patients who require long-term catheterization.
To address these issues, Access Vascular has developed a PICC constructed using a thromboresistant hydrogel material. The hydrogel consists of biocompatible polymers in the form of hydrophilic polymer chains that have been shown to resist protein absorption. At present, the new catheter has received 510(k) clearance from the FDA, and Access Vascular is proceeding with commercialization.
Medgadget had the opportunity to ask Access Vascular CEO, Jim Biggins, some questions about the product and concept.
Conn Hastings, Medgadget: Please give us an overview of the problems that catheter-related thrombus formation can cause.
Jim Biggins, Access Vascular: Thrombus formation on an indwelling catheter causes a range of complications. The most common complication is occlusion of the catheter tip which requires a clinician to administer a therapeutic to break the clot or replace the catheter entirely. Replacing a catheter is time consuming, potentially painful, and can introduce bacteria that can lead to an infection. A less common but more serious complication is deep vein thrombosis, a painful condition that requires clinician intervention. DVT can result in pulmonary embolism which can be fatal. Furthermore, there is also growing evidence of a link between thrombosis and infection.
Medgadget: How does the hydrogel material developed by Access Vascular reduce thrombus formation?
Jim Biggins: For years, clinicians have been limited to catheters based on polyurethane or silicone. When inserted into a patient, blood platelets quickly accumulate on these devices because of the natural foreign body response. Manufacturers have focused R&D efforts on developing coatings and additives to combat this, but these measures have proven to only be temporary solutions.
Access Vascular took a radically different approach and focused on developing a material which would prevent the foreign body response entirely. Our material has a high water content and a neutral surface charge which both masks the presence of the catheter and prevents blood components from adhering to the catheter body, thus preventing thrombosis accumulation. The water content also makes the catheter quite lubricious which could reduce vessel trauma and phlebitis.
Medgadget: How does the material compare with conventional catheter materials in terms of thrombus formation? How did you measure this?
Jim Biggins: Our company recently released the results of two pre-clinical studies comparing our device to conventional polyurethane devices. One study was an in vitro blood flow loop test that simulated ‘worst-case’ thrombosis conditions, and the second was an in vivo study using an ovine jugular model. Both studies achieved compelling results – our in vitro study showed a 30x reduction in thrombus accumulation versus the market leading PICC. In addition, none of our catheters occluded in either study. (A publication of the results is available on Access Vascular’s website).
Medgadget: Traditional catheter materials are strong and flexible. How does this new material compare?
Jim Biggins: We recognized early on that a complete solution must retain the functional qualities that make catheters an invaluable part of healthcare. Our 510(k) submission alone required us to conduct substantial testing to prove that our material performs in the same way that predicate devices currently on the market do. Our material is strong and load-bearing, providing ample strength for introduction and maintenance of lumen patency.
In fact, the combination of strength, lubricity, and versatility of our material may allow it to perform better than traditional catheters from a mechanical perspective. For example, there is a group of patients who are known as “difficult venous access” patients. This means that their veins are depleted or collapsed, making access with a traditional catheter difficult or impossible. Our material is soft and lubricious, yet strong, and we believe that our product will be able to achieve venous access in many of these difficult patients. That would mean that patients who would otherwise have needed a potentially dangerous central venous catheter or would have needed to sacrifice yet another vein for venous access could continue using a prior access point to receive treatment.
Medgadget: Is the new device inserted in the same manner as conventional PICCs? Will healthcare staff need any training to use the new device?
Jim Biggins: The only difference between our catheter and conventional PICCs is that nurses must briefly ‘hydrate’ the material with saline just before insertion. This step only takes a few minutes, and our team developed certain product enhancements such as a specialized catheter sheath to minimize the impact on the clinical workflow. Interestingly, we believe that our product could be introduced into the body without a micro-introducer which, in addition to reducing vessel trauma, could simplify the process of inserting the catheter.
Medgadget: Is the thromboresistant material suitable for any other medical devices? Do you have any other related products in development?
Jim Biggins: In the near-term, we are excited to be working on a new version of our device which could offer the controlled release of a drug such as an anti-infective over an extended period in addition to thrombus reduction. This device could offer a single solution to the two major complications plaguing venous access, something that has never been done before.
Looking ahead, there are plenty of opportunities across venous access, from dialysis catheters to peripherally inserted venous catheters (PIVCs) to ports. Our team recently attended the Association for Vascular Access conference in Columbus, Ohio, where we were surprised to learn that even short-dwelling PIVCs are susceptible to complications like phlebitis, occlusion and infection.
Beyond that, we see an endless number of applications for our product. Any circumstance where a load-bearing device needs to be placed into our body while preventing the foreign body response is an opportunity space for our material. There is plenty of product development to keep our R&D team busy!
See a video illustrating the concept below:
Link: Access Vascular…