Mechanical and Biological Advantages of an Ultra-Low Angle Arteriotomy – The AXERA® Self-Sealing Access Procedure
An estimated 2 million diagnostic cardiac catheterization and percutaneous coronary intervention (PCI) procedures are performed yearly in the United States, with the majority of these procedures done through femoral access. Hemostasis at the femoral arterial access site is typically achieved using either manual compression or with a vascular closure device (VCD). By reducing time to hemostasis and facilitating more rapid recovery, VCDs are able to reduce time in the recovery room, which contributes to better patient throughput, patient satisfaction, and potentially economic gains for catheterization labs. The worldwide market for vascular closure technologies has reached nearly 1 billion dollars in 2013.1
VCDs can be categorized according to two distinct methods of closure, active and passive. The strategy of active closure mechanically secures the arteriotomy and affects closure either through the approximation of the margins of the arteriotomy or the mechanical fixation of a “plug” in, or over, the arteriotomy. Examples of secured active closure devices are Angio-Seal (St. Jude Medical), Starclose (Abbott Vascular), Perclose (Abbott Vascular), and Cardiva Catalyst (Cardiva Medical), while the unsecured closure devices are the Vascade (Cardiva Medical), Mynx (AccessClosure) or Exoseal (Cordis Corporation). Unsecured implants do not suture the arteriotomy closed nor do they have an intra-arterial anchor to prevent tract implant migration. One of the major objections to the use of active devices is that they leave behind a foreign body (suture, clip, collagen plug), which may increase the risk of groin complications, particularly infection and leg ischemia. Passive closure relies on the delivery of material through the tissue tract that is placed directly on top of the puncture site in the skin and is used in conjunction with manual compression. Examples of passive closure devices include Chito-Seal (Abbott Vascular), SyvekPatch (Marine Polymer Technologies), and D-Stat Dry (Vascular Solutions). However, the clinical utility of these passive closure devices is questionable, owing to their lesser influence on hemostasis and time to ambulation.
AXERA Access Device description
A novel approach that is a modification of the gold standard Seldinger access technique has been developed to overcome the shortcomings observed with both active and passive closure devices. The AXERA Access Device from Arstasis, Inc. (Redwood City, CA) is not a VCD, but an access device that facilitates safe and effective closure. It generates a shallow-angle arteriotomy (Figure 1) designed to produce greater tissue-to-tissue contact for a stronger, more secure bond after sheath removal. Tissue-on-tissue overlap within the arterial wall and blood pressure within the arterial lumen, combined with relatively brief manual compression, facilitates rapid hemostasis without any foreign body being left behind after the removal of the sheath. Absence of a foreign body may also provide a potential advantage for re-access. The AXERA Access System was cleared by the United States Food and Drug Administration in April of 2011 for use in diagnostic catheterization through the femoral artery approach.
The safety and effectiveness of the AXERA versus manual compression has been evaluated in the SECURE-II2 and RECITAL3 (Table 1) trials, involving approximately 500 patients undergoing planned diagnostic catheterization. These trials consistently demonstrated a favorable safety profile, high procedural success rate, shorter time to hemostasis and ambulation, early sit up after sheath pull, and earlier discharge, as compared to manual compression. The safety and efficacy of the AXERA device was also evaluated in a multicenter registry for patients undergoing cardiac catheterization that was conducted in Germany, Paraguay, and the United Kingdom. Major and minor device-related complications were low, and time to hemostasis was short in both patients receiving diagnostic procedures and those who crossed over to interventional treatment (Table 2). The AXERA Access System is currently under investigation in patients undergoing common femoral artery access for PCI and/or peripheral vascular intervention.
- Global Vascular Closure Device Markets: U.S., Europe, Rest of World. Life Science Intelligence: Market reports. Available online at http://www.lifescienceintelligence.com/market-reports-page.php?id=LSI-WW.... Accessed August 26, 2013.
- Axera Access System Instructions for Use. Available online at http://www.arstasis.com/wp-content/uploads/pdfs/LBL-04003-F.pdf. Accessed August 26, 2013.
- Turi ZG, Wortham DC, Sampognaro GC, Kresock FD, Held JS, Smith RD, et al. Use of a novel access technology for femoral artery catheterization: results of the RECITAL trial. J Invasive Cardiol. 2013 Jan;25(1):13-18.
Director, Therapeutics, Research and Technology Development for the Cardiac Catheterization Program, Sinai Hospital of Baltimore, Baltimore, Maryland; Professor of Medicine at the Johns Hopkins University School of Medicine, Baltimore, Maryland; Adjunct Professor of Medicine at Duke University School of Medicine, Durham, North Carolina, shares his experience with the AXERA device.
Dr. Paul Gurbel’s translational research laboratory focuses on defining the antiplatelet effects of current and new agents, and the relation of platelet reactivity to ischemic event occurrence in patients undergoing stenting. As an interventional cardiologist, Dr. Gurbel has performed over 15,000 procedures.
What is your view on vascular closure devices (VCDs)?
Many invasive cardiologists use active VCDs in the majority of their cases, although VCDs still do not dominate the closure landscape. Industry estimates run around 40% for VCDs, 15% for radial access (no VCDs) and 45% for manual compression. I am a bit more reluctant to employ a technique for hemostasis that leaves a foreign material behind, because of concerns regarding potential ischemia/embolization and infection, particularly in patients with compromised immunity such as diabetes. However, I do find that VCDs are helpful in patients where manual compression may be difficult, particularly in obese patients and patients who have trouble lying supine. At our institution, passive closure devices are used mostly in patients where we are having difficulty in achieving hemostasis after manual sheath removal.
What has been your experience with the AXERA Access System?
I use the AXERA frequently for diagnostic catheterization, based on the favorable results of the SECURE-II and RECITAL trials. Initially, there was a learning curve, just like with any other device. However, I was comfortable using the device without supervision after my 5th procedure, which may vary by operator. Currently, I use the AXERA device in over 50% of my patients. I expect my usage will increase as more data become available in PCI patients. So far, my device success rate has been almost 100% and I have not experienced any major complications in any of my patients. In fact, several of my patients who have had a prior cardiac catheterization with manual compression have reported a more favorable post-catheterization recovery with this technique. Finally, the nurses in the recovery room have commented to me about the impressive ease of hemostasis and the short time to achieve hemostasis.
Why does this method work so well at causing rapid hemostasis post sheath pull?
There are several technical advantages of the self-sealing arteriotomy approach that potentiate faster hemostasis and a more secure method of closure. First, the device uses an ultra-low angle arteriotomy, which provides a longer and shallower angle tissue tract, allowing for increased arterial tissue-on-tissue contact. This overlap is proving to be a stronger bond and dramatically increases the amount of force necessary to re-open the arteriotomy. Bench top models have proven that the force necessary to dislodge a hemostatic clot within this smaller diameter tissue tract is significantly greater when using this approach as compared to the Seldinger method. Secondly, a longer tissue tract provides extensive exposure to tissue factors that promote the coagulation and arterial healing cascade. The greater tissue-tissue contact affords enhanced fibrin generation to seal the arteriotomy. In essence, the fibrin serves as the “glue” to seal the narrow lumen tract. Lastly, it can be hypothesized that lower pressures induced by greater resistance within the tissue tract may cause the tissue tract to easily collapse upon sheath removal. This collapse is facilitated by greater pressure in the arterial lumen. The Starling resistor principle, which has been extensively employed to model flow in airways, can be applied to the AXERA arteriotomy technique (also termed the Arstaotomy technique). The principle states that a deformable tube will collapse at a point where the pressure in the tube becomes less than the pressure in the surrounding environment. When the sheath is pulled, there is less pressure in the tissue tract, causing the tissue tract to close at that point (the choke point). A reduction in blood flow through the tissue tract is aided by the forces of the arterial lumen exerting external pressure on the tissue tract. The mechanical and biological advantages of this clinically proven self-sealing arteriotomy approach may explain the absolute absence of post-discharge re-bleeding. The implant-free nature of this approach seemingly also facilitates easy acute, late, and re-access.
Our center plans on expanding our understanding of hemostasis with the self-sealing arteriotomy technique by evaluating the influence of thrombogenicity (coagulation and platelet function) on time to hemostasis in patients undergoing cardiac catheterization treated with the AXERA femoral access system.
Disclosure: Dr. Paul A. Gurbel reports that his facility is preparing to participate in the multi-center study ASPEN, sponsored by Arstasis.
Dr. Gurbel can be contacted at email@example.com.