David H. Deaton

Five-year interim comparison of the guidant bifurcated endograft with open repair of abdominal aortic aneurysm

OBJECTIVE This study was undertaken to compare 1-year and 5-year results of endovascular repair of abdominal aortic aneurysm (AAA) with the Guidant/EVT bifurcated graft system with results of open repair. METHODS This was a prospective, nonrandomized, concurrent controlled study that compared results of endovascular versus open repair of AAA. The Phase II study with the EGS delivery system included 268 patients in 18 US medical centers; and the Phase III trial with the Ancure delivery system incuded 305 patients in 21 US institutions. Data were internally and externally audited and subjected to periodic review by the US Food and Drug Administration. The control group of 111 patients were excluded from endovascular repair with a tube graft because of anatomic considerations, but were otherwise comparable to the experimental group. Patients in the control group underwent conventional open surgical repair concurrently with patients who underwent EGS repair in 18 US institutions. RESULTS Five hundred thirty-one of 573 patients (92.7%) underwent successful implantation of the Guidant/EVT bifurcated endograft. The combined major morbidity and mortality in the endograft group was 28.8%, compared with 44.1% in the open control group. Additional benefits in the endograft group included shorter hospital stay (2 days vs 6 days), less surgical blood loss (400 mL vs 800 mL), and less intensive care unit use (33% vs 94%). These early results are reported on an intent-to-treat basis; in all patients an attempt was made to treat with the endovascular graft, including those patients in whom conversion to standard open repair was necessary during the primary procedure. Three hundred nineteen patients were selected for long-term follow-up to 5 years, on the basis of date of implantation; ie, patients with the earliest implantations were followed up for 5 years. The primary purpose of long-term follow-up was to obtain data on long-term efficacy of the graft; thus only patients in whom implantation was successful were selected. No patient has experienced an aneurysm rupture to date. Survival (Kaplan- Meier method) in the experimental group was 68.1%, compared with 77.2% in the control group (P = NS). At 60 months, 74.4% of patients (32 of 43) were free of endoleak. There were no type I or type III endoleaks remaining. Aneurysm sac diameter decreased or remained stable in 97.6% of patients (41 of 42) and increased in only 1 patient. During the course of long-term follow-up, post-procedural conversion to open repair was required in only 9 patients (2.8%). CONCLUSION The EVT/Guidant bifurcated graft is effective in preventing AAA rupture, and long-term survival is comparable to that with open repair.

Helical EndoStaples enhance endograft fixation in an experimental model using human cadaveric aortas

OBJECTIVE This study evaluated the contribution of Aptus EndoStaples (Aptus Endosystems, Sunnyvale, Calif) in the proximal fixation of eight endografts used in the endovascular repair of abdominal aortic aneurysms (EVAR). METHODS Nine human cadaveric aortas were exposed, left in situ, and transected to serve as fixation zones. The Zenith (Cook, Bloomington, Ind), Anaconda (Vascutek, Inchinnan, Scotland, UK), Endurant (Medtronic, Minneapolis, Minn), Excluder (W. L. Gore and Associates, Flagstaff, Ariz), Aptus (Aptus Endosystems), Aorfix (Lombard Medical, Didcot, UK), Talent (Medtronic), and AneuRx (Medtronic) stent grafts were proximally deployed and caudal displacement force (DF) was applied via a force gauge, recording the DF required to dislocate each device ≥20 mm from the infrarenal neck. Measurements were repeated after four and six EndoStaples were applied at the proximal fixation zone, as well as after a Dacron graft was sutured at the proximal neck in standard fashion. Finally, a silicone tube was used as a control fixation zone to test the DF of grafts with EndoStaples in a material that exceeded the integrity of a typical human cadaveric aorta and provided a consistent substrate to examine the differential effect of variable degrees of EndoStaple implantation using zero, two, four, and six EndoStaples. RESULTS In the cadaveric model, the mean DF required to dislocate the endografts without the application of EndoStaples was 19.73 ± 12.52 N; this increased to 49.72 ± 12.53 N (P < .0001) when four EndoStaples where applied and to 79.77 ± 28.04 N when six EndoStaples were applied (P = .003). The DF necessary to separate the conventionally hand-sutured Dacron graft from the aorta was 56 N. In the silicone tube model, the Aptus endograft without EndoStaples withstood 3.2 N of DF. The DF increased to 39 ± 3 N when two EndoStaples were added, to 71 ± 6 N when four were added, and to 98 ± 5 N when six were added. In eight of the 13 cadaver experiments conducted with four and six EndoStaples, the displacement occurred as a result of complete aortic transection proximal to the fixation site, indicating that aortic tissue integrity was the limiting factor in these experiments. CONCLUSIONS The fixation of eight different endografts was increased by a mean of 30 N with four Aptus EndoStaples and by a mean of 57 N with six EndoStaples in this model. Endostaples can increase endograft fixation to levels equivalent or superior to that of a hand-sewn anastomosis. The application of six EndoStaples results in aortic tissue failure above the fixation zone, demonstrating fixation strength that exceeds inherent aortic integrity in these cadavers.

The phase I multicenter trial (STAPLE-1) of the Aptus Endovascular Repair System: Results at 6 months and 1 year

OBJECTIVE This phase I IDE study (STAPLE-1) evaluated the primary endpoints of safety (major device-related adverse events at 30 days) and feasibility (successful deployment of all endograft components) of the Aptus Endovascular abdominal aortic aneurysm (AAA) Repair System (Aptus Endosystems, Inc, Sunnyvale, Calif) to treat AAAs. METHODS A prospective, single arm Federal Drug Administration (FDA) Phase I IDE study was performed. The Aptus endograft is a three-piece modular device with a flexible unsupported main body and two fully supported limbs in a 5.3 mm outer diameter (OD) (16F) delivery system for all iliac limbs and two of three main body sizes. The largest main body (29 mm diameter) is in a 6 mm (18 F OD) delivery system. EndoStaples measuring 4 mm (length) by 3 mm (diameter) designed to provide transmural graft fixation to the adventitia are applied independent of the endograft delivery system. Inclusion criteria included a proximal aortic neck length of 12 mm and iliac landing zone of 10 mm. Secondary endpoints included freedom from endoleaks, rupture, migration, and device integrity. RESULTS Twenty-one (21) patients were enrolled at five centers. All patients received the Aptus Endograft and EndoStaples. Ninety-six EndoStaples (range, 2-10; median, 4) were implanted. All patients (n = 21) completed 1-month and 6-month follow-up evaluation and 14 completed 1-year follow-up. Two proximal cuffs and one limb extension were used as adjunctive endograft components at implantation. Three secondary interventions were performed in 2 patients for limb thrombosis. There were no EndoStaple-related adverse events, device integrity failures, migrations, or conversions. CONCLUSION These results of the STAPLE-1 trial document the acute safety and feasibility of the Aptus Endograft and EndoStaples. Early follow-up demonstrates excellent 6-month and 1-year results. A pivotal phase II trial is underway at 25 US centers.

Endovascular Repair of a Common Iliac Artery Aneurysm Using the Cook Zenith Abdominal Aortic Aneurysm Endovascular Graft Converter

Isolated common iliac artery aneurysm is a rare condition that is treated aggressively because of its high risk of rupture. Endovascular abdominal aortic aneurysm (AAA) repair has recently been extended to the clinical management of the iliac artery aneurysm. Stent grafts have been used successfully to exclude iliac artery aneurysms. Successful graft deployment and aneurysm exclusion require adequate seal and fixation at the proximal and distal attachment sites. This article presents a high-risk surgical patient whose 6.8-cm-diameter iliac artery aneurysm was repaired with a Zenith AAA Endovascular Graft Converter (Cook, Bloomington, Indiana). This device is normally used to convert an aortobiiliac endograft to an aortouniiliac endograft during AAA repair. The tapered 80-mm-long graft has diameters of 24 mm proximally and 12 mm distally. Completion arteriogram demonstrated exclusion of the iliac artery aneurysm with no evidence of endoleak. No postoperative complications occurred. No endoleak was seen on the follow-up abdominal computed tomography scan.

Future Technologies to Address the Failed Endoprosthesis

Endovascular aneurysm repair (EVAR) has transformed therapy for aortic aneurysms and introduced an era of widespread use for endovascular procedures in a variety of vascular beds. While dramatic improvements in acute outcomes drove the early enthusiasm for EVAR, a realization that the integrity of the endoprostheses used for EVAR was significantly inferior to results obtained with open surgical reconstruction dampened enthusiasm for their use in low-risk patients and mandated long-term follow-up for EVAR patients. The future of EVAR as a primary approach to aortic aneurysm repair rests on development of technologies and techniques that can reproduce the foundations and, therefore, the results of open surgical reconstruction. Many of these technologies will be used initially to address the failing endoprostheses, but will have a larger role in their application as a primary component of EVAR.