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1 Department of Angiography and Interventional Radiology,
Universitätsklinik für Radiodiagnostik, AKH Wien, Währinger
Gürtel 18-20, A-1090 Vienna, Austria.
2 Division of Interventional Radiology, Stanford Medical Center, 300 Pastuer
Dr., Stanford, CA 94305.
Received April 1, 2002;
accepted after revision August 2, 2002.
Address correspondence to M. A. Funovics.
Abstract
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SUBJECTS AND METHODS. In 26 consecutive patients, the sealing device was deployed at the femoral artery access site immediately after a catheterization procedure using a 6-French (1.91-mm) sheath. Patients were followed up at 24 hr with Doppler sonography of the treated femoral artery puncture site, and at 1 week and 1 month by a telephone interview.
RESULTS. Successful hemostasis was achieved with the NeoMend Arterial Closure Device in 21 (88%) of 24 patients. One major complication required surgery: formation of puncture site hematoma and pseudoaneurysm 3 days after the intervention after successful primary hemostasis. Two device failures required crossover to manual compression, which was done without further complications. The mean time to hemostasis was 7.0 ± 4.5 min. Mean time to ambulation was 6.0 hr. At follow-up, the patients did not report any puncture-site-related complaints. Doppler sonography of the puncture sites revealed three insignificant hematomas of less than 20 mL and patent common femoral vessels without stenoses.
CONCLUSION. The NeoMend Arterial Closure Device appears to achieve rapid hemostasis with the potential of early ambulation after arterial punctures with a 6-French sheath. The device is an alternative in situations in which suture- or collagen-mediated devices show high complication rates.
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Some currently marketed devices use a collagen plug that has resulted in a decreased time to ambulation in several studies [8,9,10]. However, other studies [11] could not show the superiority of collagen sealing compared with manual compression. Some investigators found a higher complication rate, including acute femoral artery occlusion, with collagen than with manual compression [12]. In addition, with such devices, repeated access at the same site is impaired until complete resorption of the intravascular anchor of the collagen plug has been achieved.
A different approach involves the development of percutaneous vascular closure devices that deliver needles and sutures through the arterial wall around the access site. After reports of initial success [13], studies of large populations have shown a significantly higher complication rate after diagnostic procedures with such devices than with manual compression [14]. A more recently discussed limitation is the greater incidence of local infection that has been linked to the introduction of a foreign body [15].
None of these devices is a completely satisfactory solution to maximizing patient safety and comfort or to a shortened hospital stay [16]. The purpose of our study was to test the feasibility of a novel arterial closure device (NeoMend Arterial Closure Device; NeoMend, Sunnyvale, CA) that applies a rapidly and completely resorbable bioadhesive in the puncture canal to allow early mobilization after angiography. The potential advantages of this closure technique are the possibility of immediate repuncturing on the same site and the lack of excessive scar formation because of the fast resorption and biocompatibility of the adhesive, thus facilitating eventual subsequent surgery and reducing the risk of puncture site infection. To show the biocompatibility of the bioadhesive, a program of in vitro and in vivo biocompatibility testing was completed in accordance with International Standards Organization 10993-1, which regulates the selection of biocompatibility tests for a medical device [17]. The bioadhesive has been categorized as a permanent exposure implant (> 30 days, blood contact).
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Enrollment
Between July 2001 and January 2002, 26 consecutive patients were included
in the study. The mean patient age was 66.6 ± 10.8 years. Exclusion
criteria were age younger than 18 years, pregnancy, ipsilateral prior femoral
access within 30 days, history of prior femoral closure with another device,
bleeding disorders (including thrombocytopenia, activated clotting time >
300 sec), persistent hypertension (systolic blood pressure > 180 mm Hg or
diastolic blood pressure > 110 mm Hg), planned prolonged heparin or
warfarin therapy, significant anemia (hematocrit < 30%), preexisting
hematoma, or known sensitivity to polyethylene glycol.
Intervention and Medication
In the morning before the intervention, blood samples were drawn and the
activated partial thromboplastin time (aPTT) was measured. All patients
underwent retrograde common femoral artery single-wall puncture under local
anesthesia using the Seldinger technique with a 0.035-inch guidewire and the
placement of an introducer sheath with an inner diameter of 6 French (2.0 mm)
and an outer diameter of 7.2 French (2.4 mm).
Eleven of 26 patients did not receive anticoagulants during the intervention. Fifteen of 26 patients received 5000 U of unfractionated heparin sodium intraarterially and a daily dose of 100 mg of aspirin and 75 mg of clopidogrel (Plavix; Bristol-Meyers Squibb, Vienna, Austria) starting immediately after the intervention for a minimum of 6 weeks.
NeoMend Device
The Neomend Arterial Closure Device consists of two components: the
bioadhesive and the delivery device. The arterial closure device is designed
to seal arterial punctures from up to 7-French sheaths with an outer diameter
of 8.4 French (2.8 mm). The device is depicted in
Figure 1. Its total length is
176 mm, with an intravascular part 100 mm long and an outer diameter of 8
French (2.4 mm).
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The bioadhesive is a two-part mixture consisting of a polymer component (polyethylene glycol) and a protein component (human serum albumin). Mixing of the two components occurs during injection, and cross-linking of the bioadhesive occurs in situ to establish hemostasis at the femoral artery puncture site.
The distal end of the delivery device (Fig. 1) incorporates a nylon open-weave mesh locator disk that can be deployed by moving the slider on the device handle. The distal tip of the catheter shaft is radiopaque, and a radiopaque marker is proximal to the locator disk. Four to six millimeters proximal to the deployed locator disk are four exit holes for the bioadhesive. With the locator disk deployed and retracted to the inside of the vessel wall, the bioadhesive is delivered to the exterior surface of the artery and the puncture canal to establish hemostasis.
The syringe holder is a dual-chamber cartridge with cavities and Luer-Lock connectors for each syringe containing the bioadhesive constituents. The plunger of the syringe holder allows simultaneous depression of the plunger on each syringe.
Delivery of Bioadhesive and Hemostasis
The delivery catheter was placed over a compatible guidewire in the
arterial puncture site. The catheter tip was advanced into the artery. The
locator disk on the catheter was deployed, and the catheter shaft was
withdrawn until the disk made contact with the inside wall of the artery. The
dualchamber syringe holder (with bioadhesive syringes loaded) was connected to
the injection port on the delivery catheter. The plunger on the syringe holder
was advanced, injecting the bioadhesive through the catheter to the area of
the arterial puncture. The locator disk was collapsed, and the catheter and
guidewire were withdrawn from the puncture within 30 sec (Fig.
2A,2B,2C,2D,2E,2F).
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Puncture Site Management
After the application of the bioadhesive, manual compression was initiated
for 5 min to allow the material to polymerize. The puncture site was assessed
by complete removal of manual pressure every 5 min until complete hemostasis
was confirmed. The total time necessary to achieve complete hemostasis was
recorded. A compression bandage with a single transverse adhesive patch was
applied.
Follow-Up Protocol
Two hours after the closure, the puncture site was inspected clinically. If
no hematoma was palpable, the patient was encouraged to stand. After another
inspection of the puncture site, the patient was transferred to the ward. The
time to ambulation was measured from the completion of catheterization until
the patient was able to walk three to five steps independently without any
complications.
Twenty-four hours after the closure, color-coded duplex sonography of the puncture site was performed. Any stenosis, pseudoaneurysm, or hematoma was noted and quantified. Subjective patient complaints, such as local tenderness or pain, and clinical signs, such as swelling or discoloration of the skin, were assessed.
After 1 week and after 1 month, telephone interviews were undertaken in which the patients were questioned regarding local complaints about the puncture site or signs of limb ischemia. Patients with complaints were reassessed with a clinical examination, sonography, and further investigations as needed. All parameters were recorded on specific case report forms.
Study Definitions
The primary safety end point was the total number of major complications at
1 month after the intervention, and the primary procedural success end point
was the number of patients (on an intent-to-treat basis) in whom hemostasis
could be achieved within 10 min of manual compression after successful
application of the bioadhesive. Major complications included hemorrhage,
requiring surgery or transfusion; formation of a pseudoaneurysm, requiring
sonographically guided compression or surgery; nerve injury; and infection of
the puncture site, requiring antibiotic medication or surgery.
"Adjunctive compression" was defined as any standard arterial
compression beyond 10 min after application of the bioadhesive. "Failure
to deploy the adhesive" referred to the inability to correctly position
the device in the artery and was considered device failure. Non-adjunctive
arterial compression due to ongoing hemorrhage after deploying the adhesive
was termed "crossover to manual compression."
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Primary End Points
Four days after an initially successful closure procedure, one patient who
underwent renal artery stenting developed inguinal hematoma and
pseudoaneurysm, which required surgery. Four days postoperatively, the patient
was discharged without any further complaints. Thus, the rate of major
complications at 30 days was 4.2%.
For all patients, the mean time to hemostasis was 7.0 ± 4.5 min. For those 24 patients with initially successful device deployment, time to hemostasis was 6.1 ± 2.1 min.
Secondary End Points
Procedural success in obtaining permanent hemostasis was achieved in 23 of
26 patients. In addition to the one patient who required surgery, technical
device failures occurred in two patients.
In one patient who had undergone previous bypass surgery, the locator disk disconnected from the applicator during the retraction, and the additional resistance of the disk against the arterial wall was hardly felt because of excessive scar formation around the puncture site, which made it difficult to retract the device at all. In this patient, the sheath was reintroduced and the disk was easily retrieved with a snare, followed by manual compression that was performed without complications. This device separation could not be repeated intentionally when the remaining devices of this lot were tested. In one patient, hemostasis was not achieved after deployment of the bioadhesive, and another 25 min of manual compression were required. This patient was not permitted to be mobile before 24 hr for safety reasons.
We noted a 12% (3/26 patients) rate of nonpalpable, sonographically detected, clinically insignificant hematomas smaller than 20 mL (<3.4 cm in diameter). The bioadhesive itself was visible on sonography only immediately after the application as a hypoechoic mass. At the follow-up investigation, the bioadhesive was isoechoic to the surrounding tissue. The results of Doppler waveform analysis did not reveal any sign of luminal abnormality in the punctured arteries. No arteriovenous fistulas or false aneurysms were detected. Clinical examinations and follow-up investigations did not show any signs of ischemia attributable to the bioadhesive closure. All femoral access sites healed without signs of inflammation or infection. No nerve injuries were detected.
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In one patient, a device failure could be observed when the tip of the device with the locator disk separated from the device during retraction; this patient had extensive scar formation in and around the puncture canal. The locator disk was still on the guidewire and could easily be removed by placing a snare over the wire proximally to the locator disk and then removing the snare, the sheath, and the disk. However, such a device separation occurred only once in the series. The disk could not be pulled off the device by hand in the remaining devices of the same charge, so the problem was thought to derive from a single faulty device and a high resistance when the device was retracted. The manufacturer was informed of this problem, and additional testing of the connection between the device and the disk was incorporated into the quality control process.
The mean time to hemostasis in this study was 6.0 ± 2.1 min, which compares favorably with 9.6 min with collagen plugs and with 23.6-33.5 min with manual compression [19, 20]. This time is similar to the time required with suture-mediated devices, in which times to hemostasis of 5.3 ± 3.8 min have been reported [21].
Sealing the arterial puncture site immediately after diagnostic or interventional procedures improves patient comfort and may also reduce the length of hospitalization and the total procedural costs. Various sealing devices using different principles of operation have been investigated. Compared with manual compression, earlier hemostasis [22] and reduced patient discomfort [23] have resulted. However, to date none of the sealing devices has been shown to shorten the hospital stay, to decrease procedural costs, or to reduce major local complications when compared with manual compression [24]. On the other hand, some more recent studies with large collectives have reported significantly greater complication rates with sealing devices [12, 14, 15].
The approach described in this study has the potential to overcome some of the problems associated with other sealing devices. The device is easy and straightforward to use with techniques familiar to the interventional radiologist. That the components of the bioadhesive are human serum albumin and synthetic polyethylene glycol avoids the potential hazards of bovine products and minimizes the risks of allergic sensitization or other immunologic responses. A readily resorbed polymer provides less potential for excessive scar formation, which can impede subsequent interventions or surgery at the puncture site and which are known to occur with devices that use a collagen plug for sealing. In addition, some of the collagen-plug devices place a resorbable anchor in the artery lumen, which makes a reintervention at the same site impossible until the anchor is completely resorbed [25]. Further, the NeoMend Arterial Closure Device does not depend on a largely intact and uncalcified vessel wall of the common femoral artery, which is often not available in diabetic or aged patients, as opposed to suture-mediated devices, which show significantly more technical failures in such patients [14, 26].
The major goal of this first feasibility study was to assess the safety and efficacy of a new approach to vascular sealing. As a result, the measured times to hemostasis and ambulation may have been artificially prolonged, particularly in patients undergoing diagnostic procedures. As noted previously, the compression times were evaluated at 5-min intervals, with most patients showing complete hemostasis after the first 5 min. Shorter assessment intervals might have revealed that the actual time to hemostasis was even shorter than that seen in this study. Similarly, no emphasis was placed on patients becoming ambulatory immediately after the procedure. Rather, patients were mobilized after a 6-hr safety interval, although they were allowed to stand at the bedside 2 hr after the intervention.
Another concern was the risk of inadvertent intraarterial administration of the bioadhesive. With other devices, insertion of hemostatic agents or thrombogenic device parts into the artery could lead to extensive thrombosis and femoral artery occlusion with resulting limb ischemia, infarction, and potential loss of the limb [25]. Previous preclinical experiments with the bioadhesive used in this device have shown that its ability for polymerization is confined to a narrow gap of high pH and high local concentrations of the polymer components. Intravascular application would lead to immediate dilution and a decrease in pH, thereby preventing embolus formation. Intraarterial injection of the whole dose in animal experiments did not lead to formation of any arterial emboli (Milo C, NeoMend; unpublished data). In our study, no evidence of device-related embolization or ischemia was seen.
In conclusion, the NeoMend Arterial Closure Device provides a feasible, effective, and safe means of hemostasis after arterial catheterization procedures. The device provides earlier hemostasis than manual compression and has the potential for earlier patient mobilization after interventional procedures, even in patients who received anticoagulation. This device may prove especially useful in interventional settings when access site complications are frequent or after diagnostic procedures when early mobilization can lead to a significant reduction in costs. These two applications are currently being confirmed in ongoing multicenter trials.
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