Percutaneous Zenith Endografting for Abdominal Aortic Aneurysms
Article Outline
A completely percutaneous approach to infrarenal abdominal aortic aneurysm (AAA) endografting has the theoretic benefits of being minimally invasive and more expedient. Our goal was to demonstrate the utility of this approach using a suprarenal fixation device and a suture-mediated closure system. We conducted a single-institution, retrospective review of 14 patients who underwent percutaneous AAA repair with the Zenith device between August 2003 and March 2007. Immediate and delayed access-related outcomes were examined over a mean follow-up of 12.1 ± 2.0 months. Mean AAA size was 5.6 cm. Immediate arterial closure and technical success rate was 96% (27/28 vessels). One immediate hemostatic failure required open surgical repair. Over follow-up, one vessel required operative repair for new-onset claudication. No other immediate or delayed complications (thrombosis, pseudoaneurysm, infection, or deep venous thrombosis) were detected. A percutaneous approach for the treatment of AAA has several advantages over femoral artery cutdown but also has its own unique set of risks in the immediate and late postoperative period. Ultimately, the “preclose technique” can be safely applied for the Zenith device despite its large-bore delivery system.
Introduction
Endovascular aortic aneurysm repair (EVAR) is a well-accepted alternative to traditional open surgical repair given the observed periprocedural reductions in morbidity and mortality.1, 2 Device modifications have improved the delivery and durability of this technique, yet little has been done to advance the efforts to perform this procedure as an entirely percutaneous case. Obviously the options are either significant reductions in the diameter of the delivery systems or development of large-bore closure devices. For the time being, the “preclose technique” using a smaller-diameter suture-mediated closure device placed prior to introduction of the larger delivery systems has been employed.3, 4 As expected, the outcomes of this approach are highly dependent on the sheath size and experience of the operator. While several authors have demonstrated success with this technique, most reports are limited to sheath sizes under 20 Fr.2, 5
The Zenith device (Cook Inc., Bloomington, IN) is a commercially available suprarenal fixation device that can accommodate aortic diameters up to 32 mm. Unfortunately, the delivery system of the Zenith device is larger than other approved devices (16-24 Fr) and is therefore less frequently attempted as an entirely percutaneous procedure. The potential benefits of percutaneous endograft deployment include an overall shorter procedure time, improved patient acceptance, earlier ambulation, and a reduction in wound complications.6, 7 In this study, we review the early and mid-term outcomes of a series of patients who underwent complete percutaneous repair of infrarenal abdominal aortic aneurysms (AAAs) using the Zenith endograft and using the “preclose technique” with the Prostar XL suture-mediated closure device (Abbott Vascular, Redwood City, CA).
Methods
Patients and Outcome Measures
This is a single-center retrospective review of 14 AAA patients treated percutaneously using the Zenith endograft from August 2003 to March 2007. Demographic data, as well as procedural outcomes with regard to immediate and delayed access-related complications, were examined. This report was approved by the Northwestern University Medical School Institutional Review Board.
Preclose Technique
The “preclose technique,” as it has previously been described, is critically dependent on accurate placement of the puncture on the anterior wall of the common femoral artery.6, 8 Ideally this is best achieved using ultrasound guidance in conjunction with a micropuncture arterial kit (Terumo, Somerset, NJ). Once a 4 Fr sheath is placed, ipsilateral oblique imaging of the femoral bifurcation confirms exact placement of the arteriotomy proximal to the femoral bifurcation. Next, over a 0.035-inch wire, a Prostar XL 10 Fr closure device is introduced. After pulsatile bleeding is confirmed from the marker port, the sutures are deployed and retrieved. The sutures are left untied, the device is removed over a 0.035-inch wire, and the Zenith delivery system is introduced into the femoral artery. The same steps are conducted on the contralateral side. At the conclusion of the EVAR procedure, each delivery sheath is removed and the two sutures tied using a standard slip-knot while an assistant provides manual pressure above the arteriotomy. Once hemostasis is obtained, the skin incision is closed in two layers with standard absorbable sutures. Technical success in this report is defined as successful closure of the arteriotomies without the need for any other access-related adjunctive surgical or endovascular measures.
Statistics
All data are expressed as mean ± standard error of the mean.
Results
Patient Characteristics
Demographic data are provided in Table I; briefly, most of the patients were men (n = 13), and the average age was 71.9 years. Mean infrarenal AAA measurements were 5.5 cm in the anteroposterior dimension and 5.6 cm in the mediolateral dimension.
Table 1. Patient demographics
| N | % | |
|---|---|---|
| No. of Patients | 14 | |
 Mean Age (y) | 71.9 | |
| Patient weight (kgs) | ||
| Mean | 87.9 | |
| Range | 59.1-121.8 | |
| Mean AAA size (cm) | 5.5 × 5.6 | |
| Male gender | 13 | 92.9 |
| Hypertension | 12 | 85.7 |
| Coronary artery disease | 10 | 71.4 |
| Diabetes, type 2 | 2 | 14.3 |
| COPD | 1 | 7.1 |
| Hyperlipidemia | 12 | 85.7 |
| Tobacco use | 11 | 78.5 |
| Bleeding disorder | 1 | 7.1 |
| History of claudication | 1 | 7.1 |
Zenith Components and Anatomic Measurements
As seen in Table II, the main body and contralateral delivery system outer diameter (O.D.) measurements are listed along with the respective computed tomography (CT)–derived common femoral artery measurements. Either a main body 22 Fr (n = 11) or 20 Fr (n = 3) delivery system was used with associated contralateral delivery systems of 18 Fr (n = 6) or 16 Fr (n = 8).
Table 2. Zenith component outer diameter (O.D.) measurements and corresponding common femoral artery (CFA) measurements
| Patient | Main bodyO.D. (mm) | CFA (mm) | Contralateral limbO.D. (mm) | CFA (mm) |
|---|---|---|---|---|
| 1 | 22 | 11.3 | 16 | 9.5 |
| 2 | 22 | 8.0 | 18 | 7.0 |
| 3 | 20 | 10.5 | 16 | 11.5 |
| 4 | 22 | 11.0 | 18 | 11.7 |
| 5 | 22 | 9.7 | 18 | 9.8 |
| 6 | 22 | 10.9 | 16 | 11.0 |
| 7 | 22 | 9.9 | 16 | 10.0 |
| 8 | 22 | 13.0 | 16 | 13.1 |
| 9 | 22 | 9.0 | 18 | 10.1 |
| 10 | 20 | 9.8 | 18 | 9.8 |
| 11 | 20 | 9.1 | 16 | 9.1 |
| 12 | 22 | 10.5 | 16 | 10.3 |
| 13 | 22 | 10.5 | 18 | 10.9 |
| 14 | 22 | 9.3 | 18 | 10.1 |
Procedural Outcomes
All procedures were performed in an operating room angiosuite equipped with fixed imaging. General anesthesia was used in 11/14 (79%) of cases, and the remaining performed using spinal anesthesia. Only low-dose intravenous heparin (2000-5000 units) was used without the addition of protamine at the conclusion of the procedure to reverse the anticoagulant effects. The EVAR procedure successfully excluded all AAA, without evidence of Type I or Type III endoleaks. Type II lumbar-based endoleaks were present in 4 patients at the immediate conclusion of the procedure. A completely percutaneous closure was successfully achieved in 13/14 (93%) of patients and 27/28 (96%) of accessed vessels. The one immediate failure was an inability to obtain adequate hemostasis, which was treated by open surgical repair of the CFA with a prosthetic patch (patient 2). No additional direct access-related complications, including groin hematoma, pseudoaneurysm, thrombosis, deep venous thrombosis (DVT), or femoral nerve injury, were identified in the immediate postoperative period. The mean hospital length of stay was 1.4 days with a range of 1-5 days (Table III).
Table 3. Operative and postoperative outcomes
| N | (%) | |
|---|---|---|
| Operative time (min) | ||
| Mean | 119.3 | |
| Range | 95-186 | |
| Anesthesia time (min) | ||
| Mean | 131.2 | |
| Range | 101-216 | |
| Estimated blood loss (mL) | ||
| Mean | 102.7 | |
| Range | 100-200 | |
| Hospital length of stay | ||
| Mean | 1.44 | |
| Range | 1-5 | |
| Anesthesia | ||
| Spinal | 2 | 22.2 |
| General | 7 | 77.2 |
| Follow-up (months) | ||
| Mean | 12.1 | |
| Range | 1-26 |
Follow-up
Over a mean follow-up of 12.1 ± 2.0 months, one case of progressive claudication occurred on the contralateral side of the patient with the immediate Prostar failure (patient 2). Duplex imaging revealed a focal CFA stenosis, which was treated with a common femoral endarterectomy. No additional cases of new-onset claudication or pseudoaneurysm formation were detected during follow-up. CT-derived imaging showed no significant increase or decrease in the caliber of the CFA in the remaining treated patients.
Discussion
EVAR has become commonplace in the management of AAA. Currently, there exist four FDA-approved devices for the treatment of infrarenal abdominal aortic aneurysms: AneuRx (Medtronic/AVE, Santa Rosa, CA), Zenith (Cook Inc., Bloomington, IL), Excluder (W.L. Gore & Associates, Flagstaff, AZ), and Powerlink (Endologix, Irvine, CA). Traditionally, delivery has been achieved via an open femoral artery cutdown and primary repair of the artery at the conclusion of the procedure. While this has been a successful approach, there remain the problems of patient discomfort and wound complications. Attempts at a percutaneous approach using the “preclose technique” with a suture-mediated closure device have been reported with varied success.9 This method has been most successful for delivery sheath sizes under 20 Fr but has been less frequently used for the larger delivery sheaths required to deploy the Zenith suprarenal fixation stent graft or thoracic stent grafts.5 In this current report, we demonstrate the feasibility of using the “preclose technique” to facilitate an entirely percutaneous approach to AAA endografting using the Zenith device.
A major impediment to an entirely percutaneous aortic stent graft repair has been the larger sheath sizes required for the delivery of the main body device as well as the lack of a large bore closure device. Reported success rates in excess of 80% have previously been reported for 14-18 Fr sheaths, yet outcomes for larger delivery sheaths have been substantially lower.9, 10, 11, 12 In fact, early reports of achieving hemostasis after removal of large-bore sheaths using the “preclose technique” showed success rates of only 25-75%, yet one center has recently demonstrated significant improvements in technical success.9 A unique feature of the article by Lee and coworkers is that the closure was obtained by using two 6 Fr Proglide devices per femoral artery rather than a single 10 Fr Prostar XL device, which has been used in all prior reports of percutaneous EVAR.5, 13 While minor advantages and disadvantages of each can be outlined, neither is the perfect solution. This lends additional support for the need to develop a large-bore closure device intended for EVAR (Table IV).
Table 4. Report of previous reported experience on percutaneous AAA repair using large sheaths
| First author | Date | Vessels (N) | Sheath (F) | Success Rate (%) |
|---|---|---|---|---|
| Heyer (current) | 2008 | 28 | 20-22 | 96 |
| Lee | 2008 | 278 | 18-24 | 92.8 |
| Lee | 2007 | 24 | 24 | 91.7 |
| Torsello | 2002 | 27 | 14-24 | 87 |
| Traul | 2000 | 4 | 24 | 25 |
Both the Prostar XL and Proglide device have a unique set of complications that are of concern. These complications are best categorized as either immediate or delayed. Immediate complications include lack of sufficient hemostasis, thrombosis, dissection, and nerve entrapment.5 The more common reasons for lack of hemostasis are suture breaks, sutures pulling through the arterial wall, or locking of the slip knot before getting to the arterial wall. The latter occurred in our one immediate failure and can be best avoided with good subcutaneous dissection down to the artery. Fortunately, immediate failures can be corrected promptly. At our institution, all EVAR cases are performed in an operating room angiosuite, which allows for expedient exploration and repair of the common femoral artery in cases of hemostatic failure.
Delayed complications of percutaneous closure include pseudoaneurysm formation, arterial stricture, and infection.13 In our series of patients, pseudoaneurysm formation was not evident on CT imaging; however, new-onset claudication did occur in one patient shortly after the procedure. This was likely due to narrowing of a small caliber common femoral artery, which was definitively treated with open surgical repair. Infection of the sutures of the closure device is the most dreaded complication, because of the risk of delayed arteriotomy blow-out with subsequent catastrophic arterial bleeding. Frequently, this complication requires open surgical repair and in severe cases mandates wide debridement and extra-anatomic revascularization.14, 15 In a recent series by Lee et al.,19 of the 156 femoral arteries repaired, there were 3 late complications including one asymptomatic femoral artery dissection and two femoral artery pseudoaneurysms requiring surgical repair. This resulted in a late complication rate of 1.92%, which supports the relative low incidence of late complications associated with this form of closure.
The purported benefit of the three-piece bifurcated Zenith AAA Endovascular Graft is its bare suprarenal stent with barbs, which are to enhance proximal fixation and abrogate stent graft migration. Experimental studies have suggested that the suprarenal barb fixation of the Zenith endograft resists migration more rigorously than other endograft designs.16 In a single-center series, no episodes of migration were seen after treatment of 116 patients with the Zenith endograft with a mean follow-up of 10.3 ± 9.8 months.17 Furthermore, Sternbergh et al. reported endoleaks were infrequently encountered after treatment with the Zenith device (8.2% and 7.1% at 12 and 24 months, respectively) compared to rates at 12 and 24 months in AneuRx trial patients of 13.9% and 16.7%, and in Excluder trial patients, of 17% and 20%, respectively.8, 16, 18 Last, the current Zenith system allows for treatment of large aortic neck diameters of up to 32 mm, which is not possible for other approved systems.
Conclusion
In summary, an entirely percutaneous approach for the treatment of AAAs has several advantages over traditional open femoral artery cutdown and has its own set of unique risks in both the short and long term. Although technically demanding with an expected learning curve, the “preclose technique” using the suture-mediated Prostar XL closure device can be safely applied in cases of Zenith endografting of AAAs.
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PII: S0890-5096(08)00284-7
doi:10.1016/j.avsg.2008.07.007
© 2009 Annals of Vascular Surgery Inc. Published by Elsevier Inc All rights reserved.
