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This is the eighth year that I have had the privilege of writing the annual Overview of Vascular Closure in Endovascular Today. There were a number of developments in the past year, including new device approvals and changes in existing closure platforms. Vascular closure continues to grow toward the eventual billion-dollar mark, as an ever-expanding range of endovascular procedures drives the need for more efficient closure at the end of procedures. In addition, a changing reimbursement landscape, with slowly increasing adoption of outpatient interventions in the United States, will likely drive vascular closure device (VCD) use (as well as increasing transradial interventions). Although the intellectual property space is narrowing, a number of creative concepts are being explored, some of which will be covered in this edition of our annual overview.
I will review the existing technologies, discuss new devices receiving US Food and Drug Administration (FDA) clearance, and touch on some not-yet-ready for market platforms. I continue to find it useful, for both new readers as well as those familiar with the classification system, to show the various technologies classified by category (Figures 1 through 7); this time, I have included FDA-approved devices as well as some in various stages of development. This classification system, first introduced in Endovascular Today, provides a conceptual framework to allow comparison of VCDs and to anticipate the potential strengths and weaknesses of each device. I will review select items from the past year’s medical literature and will expound on fluoroscopy-guided access (see What Should Fluoroscopic Guidance Really Entail?).
ACTIVE CLOSURE:
STILL THE DOMINANT TECHNOLOGY
Angio-Seal (St. Jude Medical, St. Paul, MN) (Figure 1A)
continues to be the most widely used VCD, although its
market share may have eroded somewhat in the past year. It
remains the only “belts and suspenders” device, achieving
hemostasis with active closure that sandwiches the hole in
the artery with a resorbable anchor inside the vessel combined
with an extravascular collagen plug. The elements are
tethered together by suture. In addition, it provides the
coagulation-facilitating effect of the collagen. Primary success—the ability of the device to achieve closure without
adjunctive compression, single-operator technique, and ease
of use—are particularly strong suits of this device, with primary
success rates uniquely above 95%. The anchor inside
the artery does pose a potential hazard in vessels that are
already partly obstructed; embolization of the anchor is
quite rare. The collagen inside the tissue track provides
some additional benefit in terms of decreasing postprocedure
oozing; the suture that extends nearly to the skin surface
and the foreign body left behind temporarily in the
form of the collagen plug do create a small but important
infection risk, an issue common to all VCDs that leave even
temporary foreign bodies behind. In the past year, Angio-Seal released its Evolution platform, which improves on the
VIP version in several ways, most notably by standardizing
the force used to deliver the plug, and in general improves
consistency across users.
Perclose and StarClose (Figure 1B and 1C) remain the second most commonly used technologies. They provide active approximation without a thrombosing or sealing agent and mimic the well-established surgical techniques of suturing or stapling blood vessels. Because of the absence of suspenders—no thrombosing or sealing agent—both devices are somewhat more likely to have oozing (usually minor) after interventions in fully anticoagulated patients. Perclose dominates in one very important area: preclosure. With an ever-increasing number of procedures requiring large-sheath technology, including abdominal aortic aneurysm repair, percutaneous aortic valve replacement, and a variety of percutaneous ventricular-assist devices, the ability to achieve access and closure without surgical cutdown has become an important part of the vascular closure device arena. Operators preclose with either the ProStar XL, which provides four suture needles but has a somewhat challenging platform, or two ProGlides placed at a 40° angle. More recently, a technique has been described using three ProGlides; this presumably grabs more segments of the arterial wall and provides redundancy in case one of the closures fails.1
PASSIVE APPROXIMATORS:
CONTINUED GROWTH OF THE MYNX
The Mynx (Figure 2A) has by all accounts now gained
double-digit market share. It has the advantages of an elegant
deployment mechanism and generally excellent patient
tolerance of its sealant, polyethylene glycol (PEG). A 5-F version
(Mynx M5) was released in the past year. The device is
deployed through the procedural sheath—a desirable feature
that theoretically improves patient tolerance and may
decrease infection risk because there are fewer devices transitioning
directly across the tissue track. PEG differs from
collagen in several ways: it is a synthetic sealant rather than a
bioactive thrombosing agent, has a less fibrous consistency
than collagen, and resorbs by hydrolysis at an apparently
faster rate. However, there remains a need for solid scientific
comparison between sealants and thrombosing agents.
Several hypotheses about the Mynx remain unproven, and
unfortunately, given the volume of cases being done, the
evidence base remains lamentably scant. Unanswered questions
are (besides the role of sealants versus thrombosing
agents in achieving hemostasis) the potential for infection
associated with PEG versus collagen and the risk of distal
vessel occlusion from inadvertent deployment of the sealant
in the artery.
Most importantly, the efficacy and safety of unanchored plugs in percutaneous coronary intervention (PCI) patients remains to be shown; my bias has generally been that active (rather than passive) closure in fully anticoagulated patients is superior, but what I would consider to be a high-level evidence-based comparison study has not been published. Nevertheless, somewhat buttressing my concern is a very recent retrospective look by Azmoon et al2 at 428 patients treated with Angio-Seal or Mynx after PCI. Although that study showed no difference in major vascular complications between Angio-Seal and the Mynx, it did reveal a 2.5 times higher failure rate for the Mynx. It will be particularly important to see how often retroperitoneal hemorrhage occurs after Mynx deployment in the interventional setting (and after ExoSeal—see page 70— once that device is released) (Figure 2B), compared with Angio-Seal and Perclose/StarClose, especially in the particularly challenging setting of high punctures. In the meantime, novel uses of the Mynx continue to be published, including the use of multiple devices simultaneously for large-hole closure.3
The Cardiva Catalyst (Figure 2C) is the other mature technology that has FDA approval and can generally be categorized as a passive approximator. In order to address some of the limitations of the original Boomerang device in anticoagulated patients, it now incorporates protamine in addition to two other topical agents on the shaft of the device. These are all designed to facilitate coagulation when exposed in the tissue track after tension is placed on the cable holding the nitinol disc in place. The Catalyst has theoretical appeal for some settings where compression can be difficult or ineffective (such as brachial, although this is off-label use). The relative efficacy of this device in the interventional setting needs to be compared to active approximators. There are two factors that suggest an evidence base in the fully anticoagulated setting would be important. First is the generic issue of passive closure in this setting as discussed previously, and second, the unique feature of this device that requires that the disc be collapsed and pulled through the fresh clot formed during initial hemostasis. The disc does compress to an 18-gauge needle size according to the manufacturer, which is approximately 1.3 mm in diameter. Importantly, no foreign body is left behind.
CLOSURE BEGINS WITH ACCESS:
FDA CLEARANCE FOR ARSTASIS
This concept, which was also first introduced in this
column, now has two devices that are FDA approved:
Arstasis One and FISH (Figures 3 and 4). The two devices are
quite different with the exception of one central concept:
they both begin the closure process when access is first
obtained. This is a potential benefit and drawback: the decision
to use these devices typically needs to be made before
important details are known (location of the puncture site,
presence of any vascular disease in the common femoral
artery, or size of the common femoral artery) and in many
cases, before a decision is made on whether the procedure
will include intervention. FDA approval for both devices is
limited to diagnostic cases currently, but conversion to ad
hoc PCI means that they will of necessity be used in interventions.
The FISH is a closure device using small intestinal submucosa as a ribbon that creates a resorbable plug in the artery wall. Arstasis is unique: it is both an access and closure concept— it creates a pathway for the sheath that traverses the artery at a shallow angle and takes advantage of hydrostatic forces to facilitate closure of the artery when the sheath is withdrawn. One of several appealing features of the Arstasis approach is that it leaves no foreign body behind. My limited anecdotal experience with this technology has been positive in a number of settings about which I previously described theoretical concerns, including use in diseased and calcified blood vessels. However, much more will need to appear in the investigational literature before we have a clear understanding of the potential benefits and drawbacks of both devices. As with all the other VCDs mentioned, I remain concerned about the possible complications associated with use in the setting of high punctures and anticoagulation/aggressive antiplatelet therapy, and it will be interesting to see how these technologies fare in the real world of suboptimal access.
NEW TECHNOLOGIES: NOT FDA CLEARED
Several new, investigational technologies are worth
describing. One interesting outside-the-box concept is
CloSys, designed for use in patients who have been anticoagulated
with heparin for their procedure (Figure 5). The
device is used to withdraw a small amount of blood extracted
through a catheter placed inside the procedural sheath
and deheparinize it, followed by reinjection of 3 to 4 mL
into the tissue track above the arteriotomy site as the
sheath is withdrawn. Compression then follows. The concept
is to form a seal with coagulable blood in anticoagulated
patients, with no foreign body left behind. It is in the
early phase of clinical trials. Several questions come to mind
that will need to be answered: the effectiveness of the
method in the aggressively anticoagulated/antiplatelet
agent environment, the duration of compression ultimately
required, and the infection risk of a small amount of blood
compared with that of the foreign body left behind by most
(but not all) VCDs.
A number of companies are working on rapidly deployable mechanical closure, typically, but not exclusively, with active approximation techniques. Two such devices both have bioabsorbable intra- and extra-arterial anchors: BravoSeal (VIMedRx, Atlantic Beach, FL) and FastSeal (Vascular Closure Systems, Palo Alto, CA) (Figure 6). Another VCD in development is the Celt ACD (Figure 7), a stainless steel device with both intra- and extraluminal components that features through the procedural sheath deployment. Vascular Solutions (Minneapolis, MN) is in early testing of MagneSeal, a novel closure device delivered through the procedural sheath that uses magnesium to achieve rapid closure and resorbs in a short time frame.
ExoSeal is a passive closure device described last year that shares a number of characteristics with the Mynx, including the use of a biodegradable polymer sealant and deployment through the procedural sheath. It was the subject of a pivotal trial (ECLIPSE) published in the past year, but it is not yet FDA approved. Using the familiar Boomerang/Catalyst platform, Cardiva Medical has developed a new system that releases what is currently being described as a bioabsorbable hemostatic material into the tissue track. This device has undergone first-in-man testing in New Zealand.
LARGE-HOLE CLOSURE
The ever-increasing variety of large devices being placed in
the arterial tree is mandating renewed focus on large-hole
access and closure. A less than optimal puncture, such as
through the sidewall of the artery, may not cause significant
problems when a 6-F sheath is placed but may result in devastating
complications when a 24-F sheath is introduced. By
way of example, vascular access site complications during
completely percutaneous transfemoral aortic valve implantation
occurred in approximately one-third of patients early
in the experience, with surgical repair necessary for 10% to
20% overall.4,5 When working with sheaths and catheters
that are this large, it is essential to know ahead of time
vessel size, presence of calcification and atherosclerotic
disease, presence of iliac tortuosity and angle of insertion
into the aorta, and location of the femoral artery bifurcation.
These can all be obtained noninvasively with computed
tomography or to some degree with magnetic resonance
angiography.
Preclosure with Perclose has already been discussed in this article; a number of other innovations in both access and closure of large holes are worth mentioning. Several novel approaches use contralateral access for contrast injection to allow road mapping of the iliac and common femoral artery. A particularly clever method uses a pigtail catheter placed into the common femoral artery contralaterally, which is then used as a target for needle puncture. A means of achieving closure while minimizing risk of major blood loss involves occluding the iliac artery proximally while the sheath is pulled and the artery is closed using whatever technique is planned, such as tying of multiple sutures placed during the preclosure process.6
THE LITERATURE
I have again selected a few articles from the past year
that provide unique and important insights into vascular
closure. A study by Tiroch and colleagues7 reviewed
femoral angiography performed on 827 patients who had
at least two catheterizations between 2001 and 2008 that
involved repeat access into the same femoral artery when
angiograms were available for both procedures. Using
quantitative techniques, the investigators compared
artery size. Although the mean time between the initial
and last follow-up angiogram was less than 1 year, a number
of important observations were made. First, the procedures
appeared to have no impact on femoral artery
size. Second, the use of VCDs did not appear to affect vessel
diameters in follow-up. Interestingly, multivariate
analysis revealed a modest decrease in femoral artery size
only in women and smokers (current or in the past),
whereas vessel size increased in patients who had been on
statin therapy. By way of disclosure, we have a similar
study in the analysis phase (REPEAT) using somewhat different
methodology. An example of the appearance of the femoral artery during multiple catheterizations is seen in
Figure 8. The effect of repeat interventions over longer
periods of time on the femoral artery will be important as
the plethora of vascular interventions increases in a typical
patient’s lifetime.
A second important article was by Abu-Fadel and colleagues8 comparing fluoroscopic-guided and “traditional” femoral arterial access (using landmarks such as the inguinal crease, point of maximal pulsation, and location of the anterior superior iliac crest and symphysis pubis). The study prospectively randomized patients to fluoroscopic or traditional technique and found no difference in outcomes, although suitability for VCD use rather than complications was the basis for the sample size and power calculations. This study, as well as two other similar but less comprehensive investigations, had similar conclusions. The only benefit shown was that the incidence of puncture below the femoral head was lower with fluoroscopy. A nonstatistically significant trend, likely related, was that fewer pseudoaneurysms occurred with fluoroscopic guidance, but the study was not sufficiently powered to address this. Because the techniques outlined in the sidebar in this article were not used, 45% of the punctures were above the centerline of the femoral head, and 67%—fully two-thirds—were at or above the centerline. The technique described in Endovascular Today over the past several years has repeatedly urged that fluoroscopy be used to make certain that 100% of punctures are below the centerline of the femoral head. Thus, although this was an elegantly designed and excellently executed study, the potential benefits of fluoroscopic guidance, as it should be used in my opinion, have not been examined.
A number of other articles also deserve brief mention. The ACUITY trial (which looked at patients with acute coronary syndromes undergoing an early invasive management strategy) compared 4,307 patients receiving a VCD with 7,314 who did not and demonstrated reduced bleeding complications in patients where a VCD was used.9 As with a multiplicity of nonrandomized retrospective analyses of this type, selection bias may have favored VCD use in a more favorable population. A study by Bangalore et al10 confirmed previous reports that the occurrence of a failed VCD deployment is associated with significantly higher rates of vascular complications. Finally, renal dysfunction, a risk factor for virtually every other aspect of vascular medicine, is also associated with higher complication rates after VCD use, in particular a higher infection rate, occurring in approximately 1.7% of the patients in the study by Aziz et al.11 This is at least sixfold higher than previous reports; because VCD-related infection carries an approximately 5% mortality rate, it is one of the most dreaded complications associated with closure devices.
THE CRYSTAL BALL
After a period of relative stability in the VCD world, a
number of new technologies will become available in the
next 1 to 2 years, some of them rather creative if not revolutionary.
The mandate to access and seal femoral arteries
after large-hole closure will only increase and represents a
variety of technical and clinical challenges. I expect radial
artery access for more conventional sheath sizes to grow
dramatically in the United States in the next few years (it is
already the majority approach in some parts of the world)
for reasons discussed in this article last year. A debate
regarding femoral versus radial access, part of a series I have
the privilege of writing in Cardiac Interventions Today, will
appear in the next several months, and a debate regarding
fluoroscopic, ultrasound-guided, and traditional access will
follow later in the year. The use of topical hemostatic agents
deserves more discussion, and I plan to include that in this
space next year.
The images in Figure 8 and Figures 1 through 4 in the sidebar were prepared with the expert assistance of Brian McEniry, Dr. Turi’s research associate and supervisor of the Cooper Angiographic Core Laboratory.
Zoltan G. Turi, MD, is Director of the Section of Vascular Medicine at Cooper University Hospital and Professor of Medicine at Robert Wood Johnson Medical School in Camden, New Jersey. He has disclosed that he receives research grant support from Abbott Vascular and St. Jude Medical, and has performed consultation for Arstasis, Cook Medical, Johnson and Johnson, and St. Jude Medical. Dr. Turi may be reached at (856) 342-3488; turi-zoltan@cooperhealth.edu.
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