Zenith abdominal aortic aneurysm endovascular graft

PURPOSE: The safety and efficacy of the Zenith (Cook Inc, Bloomington, Ind) endovascular graft was assessed based on the United States multicenter trial through 5 years of follow-up. METHODS: Between 2000 and 2003, the pivotal study enrolled patients to open surgery (control) or the Zenith endovascular graft (endovascular). A separate continued access study arm enrolled endovascular patients using the same inclusion/exclusion criteria. Both studies were designed for 2-year follow-up, and the pivotal endovascular patients had the option of extending the study follow-up through 5 years. All endovascular patients were stratified by physiologic risk into high-risk and standard-risk groups to assess overall mortality, rupture, conversion, endoleaks, secondary interventions, and sac enlargement. The entire endovascular cohort was pooled to assess device integrity, limb occlusion, component separation, and migration. The suboptimal endovascular result (SER) was established as an end point to assess late adverse outcomes. Statistical analyses included Kaplan-Meier estimations and Cox regression to assess factors contributing to sac enlargement and SER. RESULTS: The study enrolled 739 endovascular patients (352 pivotal, 387 continued access); 158 patients in the pivotal study reconsented to be followed up for 5 years. For the patients at standard and high risk at 5 years, the respective survival estimate was 83% and 61%, aneurysm-related death was 2% and 4%, and freedom from rupture was 100% and 99.6%, respectively. Cumulative risk of conversion, limb occlusion, migration >10 mm, or component separation was < or =3% at 5 years. Cumulative risk of late endoleak was 12% to 15%, representing the primary indication for secondary interventions which occurred in 20% of standard-risk patients and 25% of high-risk patients through 5 years. Sac enlargement was very rare and associated with advanced age and larger aneurysms. SER was predicted by advanced age and internal iliac artery occlusion. CONCLUSION: These middle- and long-term data support long-term durability of the Zenith endovascular graft. Risk of aneurysm-related death or rupture was exceptionally low, and complications of migration, limb occlusion, and device integrity issues were uncommon. Incidence of late endoleaks and association of endoleaks with sac growth underscore the need for long-term follow-up of patients treated with endovascular grafts, although the sequelae of such events are unknown.     

Percutaneous Zenith endografting for abdominal aortic aneurysms

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.     

Fourteen-year outcomes of abdominal aortic endovascular repair with the Zenith stent graft

Objective

Long-term results of abdominal aortic aneurysm (AAA) endovascular repair are affected by graft design renewals that tend to improve the performance of older generation prostheses but usually reset the follow-up times to zero. The present study investigated the long-term outcomes of endovascular AAA repair (EVAR) using the Zenith graft, still in use without major modification, in a single center experience.

Zenith AAA endovascular graft: intermediate-term results of the US multicenter trial

PURPOSE: The intent of this study was to assess the safety and effectiveness of the Zenith AAA Endovascular Graft compared with conventional aneurysm repair. MATERIAL AND METHODS: The study was conducted in a prospective, multicenter, nonrandomized, concurrent control manner. Physiologically similar patients with infrarenal abdominal aortic aneurysms (AAAs) underwent either open surgery or repair with the Zenith AAA Endovascular Graft. Separate analyses of physiologically challenged patients were performed. Follow-up was conducted at hospital discharge and at 1, 6, and 12 months (endovascular repair group) or 1 and 12 months (open surgical repair group). Evaluation included computed tomography, abdominal radiography, laboratory tests, and physical examination. Mortality (AAA-related and overall), morbidity, in-hospital recovery, renal function, and secondary interventions were assessed. Patients in the endovascular repair group were evaluated for change in aneurysm size, endoleak, graft migration, conversion, rupture, and device integrity. Statistical analyses were performed with the Kaplan-Meier method, Blackwelder test, propensity score assessment, two-sample t test, Yates-corrected Pearson chi(2) test, and Fisher exact test. RESULTS: Conventional open surgery was used in 80 patients, and 200 patients underwent repair with the Zenith AAA Endovascular Graft. Technical success was accomplished in 98.8% of patients in the open repair group and 99.5% in the endovascular repair group. Patients in the endovascular repair group had fewer significant adverse events within 30 days (80% vs 57%; P <.001). All-cause mortality was similar (endovascular, 3.5%; open surgery, 3.8%). Aneurysm-related mortality was higher with conventional surgery at 12 months (3.8% vs 0.5%; P =.04). In-hospital recovery and procedural measures were better for endovascular repair in all categories (P <.001). The incidence of endoleak was 17% at 30 days, 7.4% at 12 months, and 5.4% at 24 months. Aneurysm shrinkage (>5 mm) was noted in more than two thirds of patients at 12 months and three fourths of patients at 24 months. Renal dysfunction rate did not differ between groups. Migration (>5 mm) was detected in four (2%) patients through 12 months; none was greater than 10 mm or associated with adverse events through 24 months. Three conversions were performed within 12 months, one because of aneurysm rupture. Secondary procedures were more common in the endovascular group (11% vs 2.5%; P =.03). In total, 351 patients had endografts implanted, and 6 patients were noted to have barb separations through 12-month follow-up. No stent fractures were noted. CONCLUSIONS: The Zenith AAA Endovascular Graft is safe and effective for treatment of infrarenal AAAs. The high likelihood of decrease in aneurysm size provides evidence that treatment of aneurysms with this device reverses the natural history of aneurysmal disease. The importance of long-term follow-up is underscored by the small but defined incidence of barb separation and the potential for unforeseen failure modes.     

Open versus endovascular stent graft repair for abdominal aortic aneurysms: an historical view

Development of endovascular abdominal aortic aneurysms repair (EVAR), now in its 4th decade, has involved at least 16 different devices, not counting major modifications of some, only 4 of which have emerged from clinical trials and gained US Food and Drug Administration approval. The main impetus behind EVAR has been its potential for significantly reducing procedural mortality and morbidity, but it was also expected to speed recovery and reduce costs through decreased use of hospital resources. At the outset, EVAR was touted as a better alternative to OPEN in high-risk patients with large abdominal aortic aneurysms, and to "watchful waiting" (periodic ultrasound surveillance) for those with small abdominal aortic aneurysms. This new technology has evoked a mixed response with enthusiasts and detractors debating its pros and cons. Bias and conflict of interest exist on both sides. This review will attempt to present a balanced review of the development and current status of this controversial competition between EVAR and OPEN, comparing them in terms of the following key considerations: mortality and morbidity, complications, failure modes and durability, and costs.     

The Cook Zenith endovascular graft

From its early release in 1994, the Zenith endovascular graft presented with a more complex but very controlled deployment mechanism. It was loaded into small and flexible introduction systems. The main difference with most early grafts was the intended suprarenal fixation with a bare stent including hooks and barbs. This suprarenal fixation proved to be both safe and efficient. Several improvements were made over the years, resulting in the Zenith Tri-Fab stent-graft. Major advantages of the Tri-Fab include availability of stock products and the versatility with regard to distal diameter and lengths. Finally, the Zenith graft acted as the platform in the development of fenestrated and branched grafts.     

Long-term outcome and reintervention after endovascular abdominal aortic aneurysm repair using the Zenith stent graft

OBJECTIVE: To assess the long-term performance of the bifurcated Zenith stent graft. METHODS: A total of 325 patients (300 men and 25 women) underwent elective endovascular abdominal aortic aneurysm repair with bifurcated Zenith stent grafts between October 1998 and December 2005. Follow-up included routine contrast-enhanced computed tomography and multiview abdominal radiographs at 1, 6, and 12 months and yearly thereafter. Data on late-occurring (>30 days after stent-graft implantation) complications and interventions were collected prospectively. RESULTS: Of the original 325 patients, 92 have since died, resulting in a mean follow-up of 2.3 years (range, 1 month to 7.0 years). Nine (2.8%) of 325 patients required reintervention to treat or prevent endoleak (type I or III) or graft occlusion at an average of 1.4 years after stent-graft placement (range, 40 days to 4.0 years). Three (0.9%) of these patients died from causes related to malfunction of the stent graft: one each from aneurysm rupture, stent-graft infection, and infection of a femoral-femoral bypass graft placed after limb occlusion. Nineteen additional patients (5.8%) required treatment for type II endoleak, for a total reintervention rate of 8.6%. CONCLUSIONS: Late failures of Zenith stent-graft attachment, structure, or function are rare. In the absence of known endoleak, routine follow-up imaging plays a limited role in the identification and prevention of impending failure.     

Impact of transrenal aortic endograft placement on endovascular graft repair of abdominal aortic aneurysms

Purpose: Successful endovascular repair of an abdominal aortic aneurysm (AAA) requires the creation of a hemostatic seal between the endograft and the underlying aortic wall. A short infrarenal aortic neck may be responsible for incomplete aneurysm exclusion and procedural failure. Sixteen patients who had an endograft positioned completely below the lowest renal artery and 37 patients in whom a porous portion of an endograft attachment system was deliberately placed across the renal arteries were studied to identify if endograft positioning could impact on the occurrence of incomplete aneurysm exclusion. Methods: Fifty-three patients underwent aortic grafting constructed from a Palmaz balloon expandable stent and an expandable polytetrafluoroethylene (ePTFE) graft implanted in an aorto-ilio-femoral, femoral-femoral configuration. Arteriography, duplex ultrasonography and spiral CT scans were performed in each patient before and after endografting to evaluate for technical success, the presence of endoleaks, and renal artery perfusion. Results: There was no statistically significant difference in patient demography, AAA size, or aortic neck length or diameter between patients who had their endografts placed below or across the renal arteries. However, significantly more proximal aortic endoleaks occurred in those patients with infrarenal endografts (P ≤.05). Median serum creatinine level before and after endografting was not significantly different between the 2 patient subgroups, with the exception of 2 patients who had inadvertent coverage of a single renal orifice by the endograft. Median blood pressure and the requirement for antihypertensive therapy remained the same after transrenal aortic stent grafting. Significant renal artery compromise did not occur after appropriately positioned transrenal stents as shown by means of angiography, CT scanning, and duplex ultrasound scan. Mean follow-up time was 10.3 months (range, 3 to 18 months). Patients who had significant renal artery stenosis (≥50%) before aortic endografting did not show progression of renal artery stenosis after trans-renal endografting. Two patients with transrenal aortic stent grafts had inadvertent coverage of 1 renal artery by the endograft because of device malpositioning, which resulted in nondialysis dependent renal insufficiency. In addition, evidence of segmental renal artery infarction (<20% of the kidney), which did not result in an apparent change in renal function, was shown by means of follow-up CT scans in 2 patients with transrenal endografts. Conclusion: Transrenal aortic endograft fixation using a balloon expandable device in patients with AAAs can result in a significant reduction in the risk of proximal endoleaks. Absolute attention to precise device positioning, coupled with the use of detailed imaging techniques, should reduce the risk of inadvertent renal artery occlusion from malpositioning. Long-term follow-up is essential to determine if there will be late sequelae of transrenal fixation of endografts, which could adversely effect renal perfusion. (J Vasc Surg 1998;28:638-46.)     

Outcome of symptomatic, unruptured abdominal aortic aneurysms after endovascular repair with the Zenith stent-graft system

OBJECTIVE: Symptomatic abdominal aortic aneurysms (AAA) account for up to 20% of patients with unruptured AAA undergoing open repair. This condition is associated with an average postoperative mortality rate after open repair of about 16%. The aim of this study was to evaluate the outcome of a consecutive series of patients who underwent endovascular repair for symptomatic, unruptured AAA. MATERIAL AND METHODS: From January 2000 to October 2006, 14 patients underwent endovascular repair of intact AAA within 15 days since admission for AAA-related symptoms. In these patients, a Zenith stent-graft (Cook Incorporated, Bloomington, IN, USA) was deployed at the Oulu University Hospital, Kuopio University Hospital and Helsinki University Hospital, Finland. RESULTS: Stent-grafting was not successful in one patient because of access failure. The procedure was immediately converted to open repair and an aortobifemoral bypass with a Dacron prosthesis was performed. In the remaining 13 patients, bifurcated Zenith stent-grafts were deployed. After the procedure, type II endoleak was observed in three patients. The mean follow-up time was 1.9+/-1.4 years. The 2-year survival rate was 69%. The survival freedom from secondary procedure was 71% as one patient underwent stent-grafting for a distal type I endoleak 5 months after the procedure. Another patient underwent femoro-femoral cross-over bypass surgery because of right limb graft thrombosis which occurred 9 months after the procedure. CONCLUSIONS: These preliminary results suggest that endovascular repair of symptomatic, unruptured AAA is feasible and can be associated with a favourable outcome despite a very high operative risk.     

An in situ adjustable endovascular graft for the treatment of abdominal aortic aneurysms.

Twenty-nine patients underwent placement of the Teramed Ariba Endovascular Graft System (Maple Grove, Minn) as part of a European Feasibility study (14 patients) and a US phase I trial (15 patients). Salient features of this modular endograft system include a crimped seamless polyester bifurcation graft supplied in three diameters and three iliac limb lengths, three types of nitinol stents including a suprarenal stent with aortic barbs, a flexible delivery system capable of controlled incremental sheath retraction, a flexible tapered lead balloon, and a telescoping technique for adjusting the length of graft coverage during surgery over a range of 3 cm. Twenty-eight of the 29 patients met the primary objective of this evaluation, which was to confirm the safety of the system, defined as the absence of major device-related adverse events and type I, III, or IV endoleaks within 1 month of implantation. Three major adverse events occurred within 1 month of discharge: renal failure, which was related to deployment of the device close to the renal arteries; pulmonary edema, which was related to the procedure but not the device; and peripheral ischemia, which was related to the patient's pre-existing condition. Seven patients had type II endoleaks noted by means of computed tomography scanning at 1 month; the endoleaks were identified by means of angiography and classified at the time of surgery. There were no deaths, aneurysm ruptures, stent-graft migrations, stent fractures, graft ruptures, graft thromboses, or surgical conversions at 1 month. This early clinical experience indicates that the Ariba Bifurcated Endovascular System can be safely implanted.     

Preliminary results of Zenith Fenestrated abdominal aortic aneurysm endovascular grafts

Background

Patients with juxtarenal aortic aneurysms who are unfit for open repair may be considered for fenestrated endovascular repair (fenEVAR). We report our initial experience with fenEVAR.

Methods

We reviewed the data on all our patients receiving fenEVAR for juxtarenal aortic aneurysms.

Results

Eight patients, average age 75 years, underwent fenEVAR. Endografts were designed from details obtained from preoperative computed tomography angiography. There were 6 grafts with superior mesenteric scallops and bilateral renal fenestrations, 1 with bilateral renal scallops, and 1 with a single renal fenestration. All patients survived 30 days. There was no renal failure requiring dialysis. At 10 weeks, 1 patient died from acute intestinal ischemia and multisystem organ failure, and another died from respiratory failure.

Conclusions

It is feasible to offer fenEVAR to patients who are poor candidates for open repair. However, these procedures are technically challenging. Early outcomes are less favorable than other aortic endovascular procedures.     

Successful endovascular repair in two cases of graft limb occlusion after endovascular aneurysm repair for abdominal aortic aneurysms

Among 148 abdominal aortic aneurysm patients who underwent endovascular aneurysm repair at our institution, two cases of graft limb occlusion (GLO) were identified and successfully treated with endovascular repair. Guidewire cannulation against the occluded limb is the most important aspect of the procedure. After a thrombectomy, balloon dilatation is performed followed by stent-graft deployment. Various procedures such as thrombectomy, thrombolysis, and extra-anatomical bypass have been adopted for the treatment of GLO. Our use of endovascular techniques, including overlapping stent grafts, has some benefits, namely, better patency of anatomical route revascularization, decreased risk of ipsilateral shower embolization due to the stent graft’s sealing over the irregular remnant thrombus, and easy access to angioplasty for tortured iliac arteries. However, shower embolization during catheter handling or future fabric failure due to friction is the potential complication associated with endovascular techniques. Intravascular repair techniques and stentgraft use should therefore be an early step of the GLO treatment algorithm.     

The endovascular management of ruptured abdominal aortic aneurysms.

Endovascular aneurysm repair (EVAR) is a controversial technique, which remains the subject of a number of prospective randomised trials. Although questions remain regarding its long-term durability objective evidence exists which demonstrates its reduced physiological impact compared with conventional open repair. If this technique could be used in patients with ruptured abdominal aortic aneurysm (AAA) it may reduce the high peri-operative mortality. A review of the literature identified a limited experience with EVAR of ruptured AAA. Only a small number of case series with selected patients exist. The majority of patients were haemodynamically stable. However, the selective use of aortic occlusion balloons allowed successful endovascular management in a small number of unstable cases. All investigators had access to an "off the shelf" endovascular stent-graft (EVG). Per-operative mortality ranged from 9 to 45% and may reflect increasing experience and patient selection. A number of patients who underwent successful EVAR were turned down for open repair. A number of important lessons have been learned from these studies but questions remain regarding patient suitability and staffing issues. If these difficulties can be surmounted then the technique may offer an alternative to open repair.     

主动脉瘤40例治疗体会

目的介绍外科与腔内隔绝术治疗主动脉瘤的体会。方法手术与腔内隔绝术治疗主动脉瘤40例,手术治疗30例,Bentall术9例,Bentall 部分弓置换3例,主动脉瘤切除人工血管置换6例,主动脉瘤切除补片修补4例,升主动脉 部分弓置换、主动脉瓣二尖瓣置换 升主动脉折叠缝合术各2例,主动脉瓣置换 升主动脉置换、主动脉瓣置换升主动脉折叠缝合术、主动脉瘤切除直接缝合、主动脉瘤切除人工血管置换 左全肺切除术各1例。腔内隔绝术治疗假性胸降主动脉瘤1例、假性腹主动脉瘤1例、夹层主动脉瘤ⅢA型1例、ⅢB型7例,经股动脉切口植入32~38mm覆膜支架。结果手术后因低心排出量综合征和出血各死亡1例,死亡率6.7%,无截瘫、偏瘫和感染。覆膜支架腔内隔绝术后1~2周内低热8例,无大出血、内漏和死亡。生存38例,随访1个月~5年,无死亡和远期并发症。结论升弓部主动脉瘤的手术治疗效果满意,覆膜支架腔内隔绝治疗DeBakeyⅢ型夹层主动脉瘤创伤小、并发症少、恢复快。