Efficacy of a bifurcated endograft versus open repair of abdominal aortic aneurysms: a reappraisal

Chronic ETA antagonist reverses hypertension and impairment of structure and function of peripheral small arteries in aortic stiffening

Arterial stiffness may contribute to the pathogenesis of hypertension. The goal of this study is to elucidate the role of Endothelin-1 (ET-1) in aortic stiffening-induced hypertension through ET_A receptor activation. An increase in aortic stiffness was created by use of a non-constrictive restraint, NCR on the abdominal aortic surface. A group of rats underwent aortic NCR or sham operation for 12 weeks and were then treated with ET_A receptor antagonist BQ-123 for 3 weeks. We found that 12 weeks of aortic NCR significantly increased pulse and mean pressure and altered peripheral flow pattern, accompanied by an increased serum ET-1 level (p < 0.05). The increase in aortic stiffness (evidenced by an elevated pulse wave velocity) caused hypertrophic structural remodeling and decreased arterial compliance, along with an impaired endothelial function in peripheral small arteries. BQ-123 treatment only partially attenuated peripheral arterial hypertrophy and restored arterial compliance, but completely recovered endothelium function, and consequently restored local flow and lowered blood pressure. Our findings underscore the hemodynamic coupling between aortic stiffening and peripheral arterial vessels and flow dynamics through an ET_A-dependent mechanism. ET_A receptor blockade may have therapeutic potential for improving peripheral vessel structure and function in the treatment of aortic stiffness-induced hypertension.

Endograft Technology: Highlights of the past 10 Years

The past decade has seen the evolution of an exciting technology that has changed forever the treatment of aortic aneurysmal disease. From rather crude homemade stent-grafts constructed in the surgical suite to elegant commercially manufactured devices in a variety of configurations and sizes, the aortic endograft has experienced a meteoric rise in popularity to become a beneficial, minimally invasive therapy that can obviate the risk of rupture and death. There are now 3 approved endovascular devices on the market for infrarenal abdominal aortic aneurysm repair, and it is likely that additional and improved devices will become available in the future. This review revisits the developmental history of the aortic endograft, noting the ongoing refinements that have arisen from our experiences with the growing population of stent-graft patients. Although research continues to search for solutions to the problems of endoleak and migration, long-term results even with the earlier second and third-generation devices are better than has been achieved with open surgical repair.

Endovascular Repair of Early Rupture of Dacron Aortic Graft

Complications after open aortic surgery pose a challenge both to the vascular surgeon and the patient because of aging population, widespread use of cardiac revascularization, and improved survival after aortic surgery. The perioperative mortality rate for redo elective aortic surgery ranges from 5% to 29% and increases to 70–100% in emergency situation. Endovascular treatment of the postaortic open surgery (PAOS) patient has fewer complications and a lower mortality rate in comparison with redo open surgical repair. Two cases of ruptured abdominal aortic aneurysm (AAA) were managed with the conventional open surgical repair. Subsequently, spiral contrast computer tomography scans showed reperfusion of the AAA sac remnant mimicking a type III endoleak. These graft-related complications presented as vascular emergencies, and in both cases endovascular aneurysm repair (EVAR) procedure was performed successfully by aortouniiliac (AUI) stent graft and femorofemoral crossover bypass. These 2 patients add further merit to the cases reported in the English literature. This highlights the crucial importance of endovascular grafts in the management of such complex vascular problems.

AAA with a challenging neck: early outcomes using the Endurant stent-graft system

OBJECTIVES

The efficacy and safety of endovascular aneurysm repair is disputable in aneurysms with a short, angulated, wide, conical, or thrombus-lined neck making a reliable seal difficult to achieve. The influence of a challenging neck on early results using the Endurant stent-graft system in high risk patients was investigated.

MATERIALS AND METHODS

A retrospective study conducted on a prospectively compiled database of 72 elective patients with challenging neck treated with the Endurant system (Endurant Stent Graft, Medtronic AVE, Santa Rosa, CA, USA). These patients were compared to a control group (n = 65) without significant neck problems. Endpoints were early technical and clinical success, deployment accuracy and differences in operative details at one month follow-up. Data are reported as mean and standard deviation or as absolute frequency and percentage (%). Normality distribution and homogeneity of variances were tested by Shapiro-Wilks and Levene tests, respectively. Inter-group comparisons for each variable were made by t-test or χ2-test or Fisher exact test. A p < 0.05 was considered statistically significant.

RESULTS

Mean age was 76.12 years; 76.6% were males. Risk factors and pre-operative variables did not differ significantly between the two groups. Mean neck length was 10.56 mm in patients with challenging anatomies and 22.85 mm in controls. Patients with a challenging neck differed significantly (p < 0.001) from controls in terms of mean infrarenal (37.67° vs. 20.12°) and suprarenal angle (19.63° vs. 15.57°); 82% of patients with a challenging neck were ASA III/IV (vs. 86%). Technical success was 100%, with four unplanned proximal extension in challenging group. No type I endoleaks or aneurysm-related deaths occurred in either group; major complications were 1.54% vs. 1.39% (p = 0.942). Operative details were similar in both groups.

CONCLUSION

Treatment with the Endurant stent-graft is technically feasible and safe, yielding satisfactory results even in challenging anatomies. Medium- and long-term data are needed to verify durability, but early results are promising.

Effects of study design and trends for EVAR versus OSR

Purpose:

To investigate if study design factors such as randomization, multi-center versus single center evidence, institutional surgical volume, and patient selection affect the outcomes for endovascular repair (EVAR) versus open surgical repair (OSR). Finally, we investigate trends over time in EVAR versus OSR outcomes.

Methods:

Search strategies for comparative studies were performed individually for: OVID’s MEDLINE, EMBASE, CINAHL, HAPI, and Evidence Based Medicine (EBM) Reviews (including Cochrane DSR, ACP Journal Club, DARE and CCTR), limited to 1990 and November 2006.

Results:

Identified literature: 84 comparative studies pertaining to 57,645 patients. These include 4 randomized controlled trials (RCTs), plus 2 RCTs with long-term follow-up. The other 78 comparative studies were nonrandomized with 75 reporting perioperative outcomes, of which 16 were multi-center, and 59 single-center studies. Of the single-center studies 31 were low-volume and 28 were high-volume centers. In addition, 5 studies had all patients anatomically eligible for EVAR, and 8 studies included high-risk patients only. Finally, 25 long term observational studies reported outcomes up to 3 years.

Outcomes:

Lower perioperative mortality and rates of complications for EVAR versus OSR varied across study designs and patient populations. EVAR adverse outcomes have decreased in recent times.

Conclusion:

EVAR highlights the problem of performing meta-analysis when the experience evolves over time.

Minimally invasive retrieval of a dislodged Wallstent endoprosthesis after an endovascular abdominal aortic aneurysm repair

Endovascular abdominal aortic aneurysm repair (EVAR) is being performed more frequently in patients with concomitant iliac artery occlusive disease. We report a case of a 70-year-old male status post angioplasty and stenting of bilateral iliac arteries for occlusive disease who subsequently underwent EVAR for a rapidly expanding abdominal aortic aneurysm (AAA). One month after the placement of the endograft, it was discovered that the previously placed Wallstent had been dislodged during the endovascular abdominal aortic aneurysm repair. Minimally invasive retrieval using an Amplatz Goose Neck Snare was successful in recovering the stent. This case underscores the danger of performing EVAR in the setting of prior iliac artery stenting and the potential complications that may ensue.

A magnetic device to eliminate endograft migration: theory and experiment

Endograft migration is a recognized problem in endovascular aneurysm repair, which may lead to aneurysm rupture, acute vessel thrombosis, or occlusion. This study presents a novel device to eliminate endograft migration that involves the use of a ferromagnetic stent graft (internal of vessel) and two magnetic rings (external to vessel, at the two necks of the stent). The magnetic rings (proximal and distal on the graft) with sufficient adhesion force were proposed to eliminate migration without overcompression of the aorta. Specifically, the objectives of the study are (1) to design the geometry and magnetic properties of the magnetic ring based on a mathematical model to produce the necessary tangential force to prevent endograft migration and (2) to validate the theoretical model with in vitro experiments. Our experimental results were in agreement with the numerical model, which showed feasibility of the approach to eliminate migration. This magnetic approach to eliminate endograft migration may lay the foundation for improvement of endograft repair of aortic aneurysm.

Long-Term Single-Center Results with Aneurx Endografts for Endovascular Abdominal Aortic Aneurysm Repair

PURPOSE

To evaluate the long-term single-center results with the AneuRx stent-graft in endovascular abdominal aortic aneurysm (AAA) repair (EVAR).

METHODS

Between December 1996 and August 2003, 212 patients (197 men; mean age 71.3+/-7.0 years) were treated with the AneuRx stent-graft for an infrarenal AAA. Postoperatively, patients were enrolled in a fixed surveillance protocol, and data were prospectively captured into a database.

RESULTS

Graft deployment was successful in 98.6% (209/212). Thirty-day mortality was 2.4%. Median hospital stay was 4.3+/-5.5 days. Median follow-up was 52.0 months (range 1-109); only 1 patient was lost to follow-up. At 9 years, patient survival was 56% and freedom from secondary interventions was 48%. In 68% of cases, these reinterventions were needed for a fixation-related complication, and most of these complications (75%) encompassed the area of the proximal aneurysm neck. Primary clinical success was 37% at 9 years. After secondary interventions, the assisted primary clinical success improved to 73% at 9 years. Freedom from aneurysm-related death was 97% at 1 year and 90% at 9 years.

CONCLUSION

As an alternative to open repair, EVAR with the AneuRx device has low perioperative mortality. Reinterventions are mostly due to fixation-related complications. While the overall mortality risk in this population was 5% per year, annual aneurysm-related death was only 1%. The focus should be on surveillance and reducing the rate of long-term complications, which might be possible with improved proximal stent-graft fixation.

Endovascular abdominal aortic aneurysm repair

The operative mortality following conventional abdominal aortic aneurysm (AAA) repair has not fallen significantly over the past two decades. Since its inception in 1991, endovascular aneurysm repair (EVAR) has provided an alternative to open AAA repair and perhaps an opportunity to improve operative mortality. Two recent large randomised trials have demonstrated the short and medium term benefit of EVAR over open AAA repair, although data on the long term efficacy of the technique are still lacking. This review aimed at providing an overview of EVAR and a discussion of the potential benefits and current limitations of the technique.

Large infra-renal abdominal aortic aneurysms: endovascular vs. open repair--single centre experience

Endovascular aneurysm repair (EVAR) has become an established alternative to open repair (OR). We present a consecutive series of 486 elective patients with large infra-renal aortic abdominal aneurysm, comparing OR with EVAR. Prospective data collected during an 8-year period from January 1997 to October 2005 was reviewed. Statistical analysis performed using SPSS data editor with chi(2) tests and Mann-Whitney U-tests. There were 486 patients with 329 OR (293 males, 36 females) with median age of 72 years with median diameter 6.3 cm and 157 EVAR (148 males, 9 females) with median age 75 years with median diameter 6.1 cm. Mortality was 13 (4%) for OR and 5 (3.2%) for EVAR (three of whom were in the UK EVAR 2 trial). Blood loss was significantly less for EVAR 500 ml vs. 1500 ml for OR. Sixty-five (19.8%) patients with OR had significantly more peri-operative complications compared with 14 (8.9%) with EVAR. The length of stay in hospital was significantly less for EVAR. This non-randomised study shows that although EVAR does not have a statistically significantly lower mortality, it does have statistically significantly lower complication rates compared with OR. EVAR can be achieved with good primary success, but long-term follow-up is essential to assess durability.

Secondary interventions following endovascular abdominal aortic aneurysm repair using current endografts. A EUROSTAR report

OBJECTIVE

The purpose of this study was to evaluate the need for secondary interventions after endovascular abdominal aortic aneurysm repair with current stent-grafts.

METHODS

Studied were data from 2846 patients treated from December 1999 until December 2004. The data were recorded from the EUROSTAR registry. The only patients studied were those with a follow-up of at least 12 months or until they had a secondary intervention within the first 12 months. The cumulative incidences of secondary transabdominal, extra-anatomic, and transfemoral interventions during follow-up (after the first postoperative month) were investigated.

RESULTS

A secondary intervention was performed in 247 patients (8.7%) at a mean of 12 months after the initial procedure within a follow-up period of a mean of 23 +/- 12 months. Of these, 57 (23%) transabdominal, 43 (16%) involved an extra-anatomic bypass, and 147 (60%) were by transfemoral approach. The cumulative incidence of secondary interventions was 6.0%, 8.7%, 12%, and 14% at 1, 2, 3, and 4 years, respectively. This corresponded with an annual rate of secondary interventions of 4.6%, which was remarkably lower than in a previously published EUROSTAR study of patients treated before 1999. Type I endoleaks (33% of procedures), migration (16%), and rupture (8.8%) were the most frequent reasons for secondary transabdominal interventions. Graft limb thrombosis was the indication for extra-anatomic bypass (60%). Type I endoleak (17%), type II endoleak (23%), device limb stenosis (14%), thrombosis (23%), and device migration (14%) were the most frequent reasons for secondary transfemoral interventions. Operative mortality was higher after secondary transabdominal interventions (12.3%, P = .007) compared with transfemoral interventions (2.7%). Overall survival was lower in patients with secondary transabdominal (P = .016) and extra-anatomic interventions (P < .0001) compared with patients without a secondary intervention.

CONCLUSION

Although the incidence of secondary interventions after endovascular aneurysm repair has substantially decreased in recent years, continuing need for surveillance for device-related complications remains necessary.

Endovascular repair of abdominal aortic aneurysms: CTA evaluation of contraindications

Endovascular aortic aneurysm repair (EVAR) is considered an acceptable alternative to open surgery in selected patients. Its feasibility depends mainly on anatomic factors that represent the important predictors of success and the most important exclusion criteria. Poor anatomic patient selection is generally associated with a higher risk for procedural complications and compromised long-term outcomes. Therefore pretreatment imaging is crucial for evaluating patient suitability for EVAR. Multidetector computed tomographic angiography represents the current standard of reference in the evaluation of the abdominal aorta and iliac axis anatomy because it provides all the details needed for selection of patients who are suitable for endograft and the choice of the appropriate device. This report identifies and reviews computed tomographic angiographic anatomic contraindications for EVAR.

Endograft technology: highlights of the past 10 years

The past decade has seen the evolution of an exciting technology that has changed forever the treatment of aortic aneurysmal disease. From rather crude homemade stent-grafts constructed in the surgical suite to elegant commercially manufactured devices in a variety of configurations and sizes, the aortic endograft has experienced a meteoric rise in popularity to become a beneficial, minimally invasive therapy that can obviate the risk of rupture and death. There are now 3 approved endovascular devices on the market for infrarenal abdominal aortic aneurysm repair, and it is likely that additional and improved devices will become available in the future. This review revisits the developmental history of the aortic endograft, noting the ongoing refinements that have arisen from our experiences with the growing population of stent-graft patients. Although research continues to search for solutions to the problems of endoleak and migration, long-term results even with the earlier second and third-generation devices are better than has been achieved with open surgical repair.

Device Migration after Endovascular Abdominal Aortic Aneurysm Repair: Experience with a Talent Stent-Graft

PURPOSE

Device migration (DM) may cause late failure after endovascular aortic aneurysm repair (EVAR). Computed tomography (CT) scans following EVAR were reviewed to establish the frequency of DM and whether it can be predicted.

MATERIALS AND METHODS

Fifty-five patients underwent EVAR with a Talent stent-graft with suprarenal fixation. CT with a fixed protocol was performed at regular intervals. Patient demographics, risk factors, procedure details, and follow-up events were reviewed. Two observers, blinded to each other, reviewed axial images and mutliplanar reformats of the CT scans. DM was defined as a change of > or = 10 mm in the distance between a reference vessel (celiac axis/superior mesenteric artery) and the proximal device. Follow-up was performed for a minimum of 2 years (mean, 3 years; range, 2-5 years).

RESULTS

DM was detected in six of 38 patients (15.8%) by 2 years. There were no new cases of migration in the 19 patients at 3 years but one new case in the six patients at 4 years (16.6%). Mean migration over 2 years was 4.8 mm +/- 4.2 mm. One patient with DM developed a type I endoleak that required reintervention. This patient developed a further endoleak and died following surgery for rupture. Top neck enlargement was the only predictive factor identified, present in 71% of patients with DM (P = .056).

CONCLUSION

DM occurred in a small proportion of patients; closer follow-up intervals may be necessary in patients with short/enlarging proximal necks.

Endovascular graft limb occlusion

Endovascular aneurysm repair (EVAR) has undergone a tremendous evolution in the nearly 15 years since it was first described. Continual refinement of the technology and techniques associated with EVAR and the respectable short-term results of this procedure led the United States Food and Drug Administration to approve several devices for the endovascular treatment of abdominal aortic aneurysm (AAA). There has been a corresponding rapid dissemination of this technology throughout the vascular surgery community in the United States. Availability and critical analysis of mid- and long-term follow-up data on the increasing number of patients who have undergone EVAR has begun to raise questions about the long-term durability and effectiveness of EVAR. Numerous complications of EVAR are now recognized and well described in the literature. One of these is graft limb dysfunction. Graft limb occlusion occurs in a significant number of patients and it is imperative that physicians who perform EVAR have a thorough understanding of this condition. There are a variety of factors that predispose patients to development of graft limb occlusion. These factors can be classified as either anatomic or graft-related. When patients present with graft limb occlusion, endovascular treatment is usually possible and it is highly effective. Some cases require traditional surgical treatment. Prevention of graft limb occlusion is of paramount importance. It can only be achieved with an aggressive search for graft limb compromise and liberal use of angioplasty and/or stenting at the time of graft implantation.

A mathematical model to predict the in vivo pulsatile drag forces acting on bifurcated stent grafts used in endovascular treatment of abdominal aortic aneurysms (AAA)

Endovascular treatment of abdominal aortic aneurysms (AAA) is a promising new alternative to the traditional surgical repair. However, the endovascular approach suffers problems such as stent graft migration, endoleaks and stent mechanism breakage. Fatigue failure is believed to be the major cause of stent graft migration and device breakage. Knowledge of the in vivo forces acting on such devices is a basic requirement for the design of a successful endovascular device. Using a Fourier series trigonometric fit of a typical pressure and flow relationship, a mathematical model, using the control volume method, was developed to predict the pulsatile drag forces acting on various bifurcated stent graft geometries. It was found that for an iliac angle of 30 degrees, a proximal diameter of 24 mm and an iliac diameter of 12 mm, the drag force varied, over the cardiac cycle, between 3.9 and 5.5 N in the axial direction. It was noted that for a specific iliac angle the drag force variation with proximal diameter approximates a quadratic fit, with an increase in proximal diameter producing an increase in drag force. The more compliant the aorta the higher the drag force. Previously published results demonstrated the axial loads (axial drag forces) required for stent graft migration for certain stents types are lower than the drag forces calculated in this study. It is believed that the results of this study can provide guidelines for the quantitative analyses of the in vivo drag forces experienced by stent grafts and could therefore be used as design criteria for such devices.

Abdominal wall hernias after open abdominal aortic aneurysm repair: prospective radiographic detection and clinical implications

The purpose of this study was to evaluate the prevalence of radiographically detected abdominal wall defects (AWD) after open abdominal aortic aneurysm (AAA) repair and to correlate it with prospectively gathered clinical information. Fine collimation, high-resolution, serial follow-up computed tomography (CT) scans for 99 patients in the control group of the Guidant Ancure device trial were reviewed. CT scans were obtained at 12, 24, 36, 48, and 60 months. AWDs, defined as discontinuity of the fascial layer with protrusion of abdominal contents, were identified. Clinical information regarding AWDs was retrieved from the study registry. The prevalence of AWD exceeds 20% and plateaus at 24 months. Eight patients (8%) had clinical evidence of ventral incisional hernias. One patient underwent repair, but no other patient developed hernia incarceration or intestinal obstruction or required additional procedures related to the AWD. AWDs are radiographic findings occurring frequently after open AAA repair. Radiographic evaluation is more sensitive than clinical observation for detection of ventral hernias. Clinical events and reinterventions related to these radiographic abnormalities are rare.

Open Versus Endovascular Repair of Abdominal Aortic Aneurysms: What Does Each Really Cost?

Endovascular repair (EVAR) of abdominal aortic aneurysm (AAA) has emerged as an alternative to open repair (OR). The aim of this study was to compare the clinical outcomes and specific costs of these procedures since commercialization.A retrospective analysis of 119 consecutive infrarenal AAA repaired via an EVAR or an OR between July 2000 and September 2001 was performed. Patient charts were reviewed. Diagnostic-related group (DRG) classification and payer mix were identified. The hospital cost accounting system was accessed to obtain actual variable direct cost (AVDC) for the two groups. Percentages of the mean AVDC for the two groups were compared in the following cost categories: graft, operating room, radiology procedures and supplies, pharmacy, respiratory therapy, clinical laboratories, surgical floor, and monitored unit. Hospital profit margins were determined. Fifty-five patients underwent EVAR and 64 patients underwent OR. Mean aneurysm size was 5.5A cm (EVAR) and 6.1A cm (OR). Mean intensive care unit (ICU) stay was 0.09 days for EVAR vs. 3.5 days for OR ( p < 0.05). Mean length of stay (LOS) was 1.96 days for EVAR vs. 7.3 days for OR ( p < 0.05). Reimbursement was based on DRG 110, 47.3% in the EVAR and 79.7% in the OR group ( p < 0.05), and DRG 111, 50.9% in the EVAR group and 12.5% in the OR group ( p < 0.05). The payer mix showed no significant differences between the two groups. Mean AVDC for EVAR was 1.74 times that of OR. Significant differences in the distribution of costs were found in the following: graft costs (58% vs. 6.3%, p < 0.05), radiology procedures and supplies (3.9% vs. 0.1%, p < 0.05), pharmacy (1.9% vs. 10.5%, p < 0.05), and monitored unit (7.3% vs. 24.65%, p < 0.05) comparing EVAR vs. OR, respectively. Median cost of an endovascular graft was 22.4 times that of the standard graft for OR. Average hospital profit margins for an EVAR case was 49.5% vs. 88.6% for OR. Despite significant differences in monitored unit utilization, pharmacy services, and respiratory therapy services by the OR group, the cost of EVAR is appreciably more expensive. Furthermore, increased DRG reimbursement, and decreased ICU use and LOS do not compensate for the cost of EVAR. The main cost of EVAR is the cost of the graft itself. Hospital profit margins are acceptable with both the EVAR and OR procedures at this time; however, with proposed reductions in reimbursement, the ability to cover the cost of this new technology may be threatened.

Perioperative complications and early outcome after endovascular and open surgical repair of abdominal aortic aneurysms

BACKGROUND

Open repair (OR) of abdominal aortic aneurysms (AAAs) is a major surgical procedure with elevated morbidity and a low but definite mortality. Advocates of endovascular repair (EVAR) claim decreased complication rates and outcome equal to OR.

METHODS

Data of all patients with infrarenal AAA that was treated electively, both with OR and EVAR, at Mayo Clinic Rochester between December 1, 1999 and December 1, 2001 were retrospectively reviewed. Thirty-day morbidity and mortality and early clinical outcomes were assessed and compared.

RESULTS

Three hundred fifty-five patients underwent treatment: 261 patients, including 229 males and 32 females (mean age: 73 years; range: 52 to 90 years) underwent OR, and 94 patients including 85 males and 9 females (mean age: 77 years; range: 61 to 98 years) underwent EVAR (AneuRx: 53, Ancure: 38, Endologix: 3). Median AAA size was 57 mm in both groups. There were more high-risk patients in the EVAR group (27% vs 14%, P =.007). Thirty-day mortality rates were 1.1 % (3/261) for OR and 0 for EVAR (P = NS). Cardiac and pulmonary complications were less frequent after EVAR (11% vs 22%, P =.02, and 3% vs 16%, P =.001, respectively), but graft-related complications were more frequent (13% vs 4%, P =.002). The association between type of repair and cardiac, pulmonary, and graft complications remained statistically significant after adjusting for age, gender, and high-risk status. The multivariate odds ratios (EVAR vs OR) for cardiac, pulmonary, and graft complications were 0.35 (95% confidence interval [CI]: 0.17 to 0.74), 0.14 (95% CI: 0.04 to 0.47), and 3.81 (95% CI: 1.51 to 9.58), respectively. Primary and secondary patency and freedom-from-reintervention rates at 1 year were lower after EVAR (83% vs 98%, P <.001; 96% vs 99%, P =.02; 65% vs 93%, P <.001, respectively).

CONCLUSIONS

Both elective OR and EVAR can be performed with low mortality, but cardiac and pulmonary complications are less frequent and less severe after EVAR. The tradeoff of EVAR is a higher rate of graft-related complications, with more reinterventions and a lower graft patency rate at 1 year. These results should be considered before EVAR is offered to patients with AAA.

Outcome of abdominal aortic aneurysm repair in the era of endovascular treatment

Background

The effect on outcome of the introduction of endovascular techniques for the exclusion of abdominal aortic aneurysm (AAA) is largely unknown. The aim of the study was to contrast the early and mid-term outcome after open and endovascular AAA repair.

Methods

Consecutive patients who underwent transfemoral endovascular aneurysm repair (EVAR; n = 93) between April 1998 and January 2003, or conventional open aneurysm repair in the time intervals before (n = 113) and after (n = 82) the introduction of EVAR were studied. All data were collected prospectively. All patients underwent elective and primary repair. Patient survival was calculated by the Kaplan–Meier method and the possible predictive value of more than 25 perioperative variables on five outcome variables (length of intensive care unit stay, morbidity, and 30-day, 6-month and overall mortality) was assessed by multivariate analysis.

Results

There were no differences in risk profiles between the three groups. Selection for EVAR was based on anatomical grounds only. All five outcome variables were significantly better with EVAR than either former or recent open repair. The only significant predictors of failure were advanced age and the need to perform an additional procedure for former open repair; hypertension and the preoperative use of anticoagulants for recent open repair; and renal insufficiency and pulmonary insufficiency for EVAR.

Conclusion

EVAR offered considerable benefits compared with conventional open repair at early and mid-term follow-up, which was not explained by selection of patients with a favourable risk profile. In the current era, in which patients are selected for open repair as a consequence of unfavourable anatomy, morbidity and mortality rates following conventional open treatment of AAA have increased at early and mid-term, but not at long-term, follow-up.

Multicenter pivotal trial results of the Lifepath System for endovascular aortic aneurysm repair

PURPOSE

This study was undertaken to assess the results of endovascular aortic aneurysm repair with the Lifepath abdominal aortic aneurysm (AAA) graft system.

METHOD

In a prospective clinical trial, 23 centers used the Lifepath System balloon-expandable, modular bifurcated stent graft for elective endovascular aortic aneurysm repair. Stent grafts were sized according to computed tomographic angiography-based diameter measurements. All repairs were performed in the operating room through bilateral surgically exposed femoral arteries. Results were assessed with contrast agent-enhanced computed tomography scans and plain abdominal x-ray films at 1, 6, 12, 24, 36, and 48 months postoperatively.

RESULTS

Over 52 months (mean follow-up, 11 months), 227 patients (206 men, 21 women) were enrolled. Technical implant success rate was 98.7%. There were five (2.2%) conversions to open surgery: two emergently because of aortic perforation; to treat refractory endoleak, immediate in one and at 12 months in one; and to replace a device with wireform fractures that had migrated at 12 months, resulting in a proximal endoleak. The perioperative mortality rate was 1.3%. There was one operative death during a secondary procedure to repair perforation of the aorta. There were two perioperative deaths, from postoperative myocardial infarction (n = 1) and pulmonary embolus (n = 1). There were 12 late deaths, from coronary artery disease (n = 4), cancer (n = 2), respiratory failure (n = 2), sepsis (n = 1), or unknown cause (n = 3). Median length of stay was 2 days (mean, 4 days). There have been no AAA ruptures after successful implantation of the device, no graft limb thromboses, and no limb dislocations. At the time of operation endoleak was noted in 43 (19%) patients, but by 6 months this was reduced to 8 (5.9%) patients (type I, n = 1; type II, n = 7). There were no type III or type IV endoleaks. Secondary interventions to treat endoleaks included open conversion (n = 2), placement of extension cuffs (n = 4), repeated balloon dilation (n = 3), and coil embolization (n = 6). The two remaining secondary interventions were emergent treatment of postoperative bleeding from a groin incision, and a colon resection because of postoperative colonic ischemia, for a 12-month secondary intervention rate of 7.5%. Wireform fractures were noted in the first generation Lifepath device in 37 of 79 (47%) patients. Graft migration (>10 mm) was observed in five patients (2.2%), each of whom also had two or more fractures of the proximal anchoring wireforms. Migration resulted in a proximal attachment endoleak in one patient. In response to wireform fractures, the device was modified after the initial 79 patients were enrolled. Wireform fracture has been observed in six patients since this modification (4%), and in only one patient did this involve fracture of a proximal anchoring wireform; none of these patients has had endoleak or graft migration. By 12 months, mean aneurysm diameter was noted to decrease by 9 mm (P <.0001), and mean aneurysm volume by 42 mL (P <.0001) from the preoperative visit.

CONCLUSION

The Lifepath System demonstrates a low endoleak and secondary intervention rate and high sac regression rate, compared with other devices. The unique balloon-expandable design offers the advantages of precise placement and high radial force. The device appears to be highly resistant to limb thrombosis and modular component separation. Patients were protected from AAA rupture after successful device implantation, and demonstrated significant reduction in AAA diameter and volume. Fractures of the wireforms of the main body of the device have been observed. Careful long-term follow-up is necessary.

Diameter of abdominal aortic aneurysm and outcome of endovascular aneurysm repair: does size matter? A report from EUROSTAR

OBJECTIVES

This study was undertaken to determine the effect of the preoperative diameter of abdominal aortic aneurysms on the midterm outcome after endovascular abdominal aneurysm repair (EVAR).

METHOD

The data for 4392 patients who had undergone EVAR were analyzed. Patients were enrolled over 6 years to June 2002 in the EUROSTAR database. Outcomes were compared between three groups defined by the preoperative diameter of the aneurysm: group A (n = 1962), 4.0 to 5.4 cm; group B (n = 1528), 5.5 to 6.4 cm; and group C (n = 902), 6.5 cm or larger. Patient characteristics, details of aortoiliac anatomy, operative procedures, old or current device generation, and postoperative complications in the three patient groups were compared. Outcome events included aneurysm-related death, unrelated death, conversion, and post-EVAR rupture of the aneurysm. Life table analysis and log-rank tests were used to compare outcome in the three study groups. Multivariate Cox models were used to determine whether baseline and follow-up variables were independently associated with adverse outcome events.

RESULTS

Patients in group C were significantly older than patients in groups A and B (73 years vs 70 and 72 years, respectively; P =.003 - P <.0001 for different group comparisons), and more frequently were at higher operative risk (American Society of Anesthesiologists classification >or=3; 63% vs 48% and 54%; P =.0002-P <.0001). Device-related (type I) endoleaks were more frequently observed at early postoperative arteriography in group C compared with groups A and B (9.9% vs 3.7% and 6.8%; P =.01-P <.0001). Postoperatively systemic complications were more frequently present in group C (17.4% vs 12.0% in group A and 12.6% in group B; P <.0001 and.001). The first-month mortality was approximately twice as high in group C compared with the other groups combined (4.1% vs 2.1%; P <.0001). Late rupture was most frequent in group C. Follow-up results at midterm were less favorable in groups C and B compared with group A (freedom from rupture, 90%, 98%, and 98% at 4 years in groups C, B, and A, respectively; P <.0001 for group C vs groups A and B). Aneurysm-related death was highest in group C (88% freedom at 4 years, compared with 95% in group B and 97% in A; P =.001 and P <.0001, respectively; group B vs A, P =.004). The annual rate of aneurysm-related death in group C was 1% in the first 3 years, but accelerated to 8.0% in the fourth year. Incidence of unrelated death also was higher in groups C and B than in group A (76% and 82% freedom at 4 years vs 87%; P <.0001 for both comparisons). Ratio of aneurysm-related to unrelated death was 23%, 21%, and 50% in groups A, B, and C, respectively. Cox models demonstrated that the correlation between large aneurysms (group C) and all assessed outcome events was independent and highly significant. Older generation devices had an independent association with aneurysm-related and unrelated deaths (P =.02 and P =.04, respectively). However, this correlation was less strong than large aneurysm diameter (P =.0001 and P =.0009, respectively).

CONCLUSIONS

The midterm outcome of large aneurysms after EVAR was associated with increased rates of aneurysm-related death, unrelated death, and rupture. Reports of EVAR should stratify their outcomes according to the diameter of the aneurysm. Large aneurysms need a more rigorous post-EVAR surveillance schedule than do smaller aneurysms. In small aneurysms EVAR was associated with excellent outcome. This finding may justify reappraisal of currently accepted management strategies.

Ruptured Abdominal Aortic Aneurysm: Endovascular Repair is Feasible in 40% of Patients

INTRODUCTION

Open repair of ruptured abdominal aortic aneurysm (rAAA) still has a high mortality. Endovascular aortic repair (EVAR) may be the way to improve survival rates. However, it is not clear how many patients with rAAA will be suitable for acute EVAR.

METHODS

Between October 2000 and April 2002 all patients with acute symptomatic or ruptured AAA were assessed for EVAR on an intention-to-treat basis with emergency computed tomographic angiography (CTA). Patient and logistic characteristics were analysed. We used two commercially available aorto uni-iliac devices with a maximum proximal diameter of 28 and 34 mm.

RESULTS

Five out of 26 patients were excluded for CTA and EVAR because of severe and persistent hypotension (3 pts) or logistic reasons (2 pts, both eligible). Twelve patients were found not eligible for EVAR due to unsuitable infrarenal aortic neck length (3 pts), neck diameter (1 pt) or a combination of both (8 pts). The remaining six patients were treated with EVAR. After 6 months no graft failure or aneurysm related deaths were recorded in the EVAR group.

CONCLUSION

A total of 28% of patients with symptomatic or ruptured AAA was treated with EVAR. A potential 42% of patients could have been suitable for EVAR, if the correct devices had been in stock and all patients had been properly assessed.

Percutaneous Drainage and Explantation of an Infected Aortic Endoluminal Stent Graft

Endoluminal repair of abdominal aortic aneurysms (AAAs) has undergone explosive growth in the last decade. Although immediate benefits are attractive to both the patient and the treating physician, concerns regarding long-term success have dampened sustained enthusiasm for this technique. A rare but catastrophic complication is stent graft infection. This case report describes an early infection of an endoluminal aortic stent graft treated initially with percutaneous drainage and ultimately with staged extraanatomic bypass and graft explantation.

Does the wide application of endovascular AAA repair affect the results of open surgery?

PURPOSE

to examine the effect of the adoption of endovascular aneurysm repair (EVAR) on the outcome of open repair (OR).

METHODS

between May 1998 and December 2001, EVAR (Zenith) was performed in 117 patients, and OR was performed because of anatomic restrictions in 40 (group A), and because of young age in 11 patients (group B).

RESULTS

EVAR patients had higher ASA classifications (p < 0.0001). EVAR was associated with a 98.3% (115 patients) technical success rate, one conversion to OR and one fatal cardiac arrest. Thirty-day mortality was 2.6% (3 patients) in EVAR, 15% (6 patients) in group A and none in group B. There was no difference in late survival between the three groups. Late reinterventions, mainly endovascular, were more frequent in EVAR. At a median follow-up of 17 months one stent-graft had migrated 5 mm distally and five stents had fractured, but without clinical consequence.

CONCLUSIONS

EVAR provides good results even with inclusion of high-risk patients. The adoption of EVAR may adversely affect the results of OR offered to patients because of anatomic considerations. However, OR continues to be the first option for low-risk young patients.

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.

The Gore Excluder US multi-center trial: analysis of adverse events at 2 years

Although open surgical repair of abdominal aortic aneurysms remains the standard of care, endovascular repair is becoming an attractive alternative as more long-term outcome data become available to show its safety and efficacy. The authors review data on the 2-year outcome of the pivotal US multicenter, prospective Gore Excluder Trial. Patients treated with the Excluder endograft (W.L. Gore, Flaggstaff, AZ) had less blood loss (310 +/- 19 v 1,590 +/- 124 mL; P <.0001), required fewer homologous transfusions (6% v 32%; P <.0001), and had faster inpatient recovery (2.0 +/- 0.1 v 9.8 +/- 1.4 days; P <.0001) compared with those treated with open repair. Early major adverse events were reduced significantly in the patients treated with the endograft (14% v 57% in control; P <.0001), and this persisted at 2 years. There was no difference in overall survival rate (P =.13). There were no deployment failures, early conversions, or aneurysm ruptures. At the 2-year time-point, trunk migration occurred in 1%, limb migration in 1%, limb narrowing in 1%, endoleak in 20%, and aneurysm growth in 14%. There was a 7% annual reintervention rate in the endograft group in the first 2 years. The Excluder endograft is a safe and effective treatment compared with open surgical repair for infrarenal abdominal aortic aneurysms with appropriate anatomy.

Effect of suprarenal versus infrarenal aortic endograft fixation on renal function and renal artery patency: a comparative study with intermediate follow-up

PURPOSE

Suprarenal fixation of aortic endografts appears to be a safe option in patients with a short or conical proximal aortic neck. However, concern persists regarding the long-term effect on renal function when renal artery ostia are crossed by the uncovered stent. We investigated the effect of suprarenal versus infrarenal endograft fixation on renal function and renal artery patency after endovascular aortic aneurysm repair.

METHODS

Records of 91 patients who underwent endovascular aortic aneurysm repair with a modular bifurcated stent graft between November 1999 and January 2002 were reviewed retrospectively. Two patients receiving dialysis because of chronic renal failure were excluded. Infrarenal fixation was used in 57 patients (group 1), and suprarenal fixation was used in 32 patients (group 2). In two patients in group 1 a Gianturco Z stent was inserted transrenally because of intraoperative proximal type I endoleak, and data for these patients were excluded from analysis. Follow-up evaluation was performed at 1, 6, and 12 months, and yearly thereafter, and included clinical assessment, measurement of serum creatinine concentration (SCr), and computed tomography angiography, per standard protocol. Median follow-up was 12 months (range, 1-36 months).

RESULTS

There was no statistically significant difference in patient demographic data, aneurysm size, or preoperative risk factors. Median SCr was significantly higher in group 2 (suprarenal fixation) than in group 1 (infrarenal fixation) preoperatively (1.2 mg/dL [range, 0.6-2.3 mg/dL] vs 0.9 mg/dL [range, 0.6-1.9 mg/dL], P =.008) and at 1 month postoperatively (1.1 mg/dL [range, 0.8-5.6 mg/dL] vs 1.0 mg/dL [range, 0.6-2.1 mg/dL], P =.045). There was a significant increase in median SCr in both groups at 1 month postoperatively (group 1, 1.0 mg/dL [range, 0.6-2.1 mg/dL], P =.05; group 2, 1.1 mg/dL [range, 0.8-5.6 mg/dL] [mean SCr, 1.35 mg/dL vs 1.15 mg/dL, respectively], P <.05). In group 1 SCr was increased significantly at 6 and 12 months (P <.001), whereas in group 2 SCr also increased at 6 and 12 months, but not significantly. The change in SCr over time was not significantly different between the two groups. In two of 32 patients in group 2, renal artery occlusion developed, associated with perfusion defects in renal parenchyma and persistently elevated SCr. Analysis of renal artery patency did not demonstrate any association between patency and treatment. No patient developed hypertension during follow-up.

CONCLUSIONS

Suprarenal endograft fixation does not lead to significant renal dysfunction, and renal artery occlusion is uncommon within 12 months. A larger study with longer follow-up is essential to determine overall effects on renal function and renal artery patency.

Two-dimensional versus three-dimensional CT scan for aortic measurement

PURPOSE

To examine if 3-dimensional (3D) reconstructions of computed tomographic (CT) data, by imaging perpendicular to blood flow, can improve aortic diameter measurement accuracy over axial (2D) CT.

METHODS

Two independent, blinded observers used electronic calipers to measure the minor axis and the line perpendicular to it on 40 2.5-mm 2D CT scans from 31 patients. A circular electronic tool was used to estimate diameters on 3D reconstructions from the same 40 scans. Measurements of the aortic neck were obtained 5 mm below the renal arteries and the widest slice of the aneurysm was used to measure sac diameter. Only the minor axis was measured at the iliac arteries immediately above the left (LI) and right (RI) iliac bifurcations. Datasets were compared with an intraclass correlation coefficient (ICC), Bland and Altman variation assessments, and absolute differences.

RESULTS

ICC between 2D and 3D scans demonstrated high correlation with 2D minor axis measurements (neck=0.9282, sac=0.8956, RI=0.8755, LI=0.7381). 3D to 2D major axis correlation was lower (neck=0.6388, sac=0.8995). Variation between 3D and 2D minor axis measurements was low (0.51-mm average variation from the mean for the minor axis and 1.30-mm variation for the major axis). Average absolute difference between 3D and 2D diameters was 1.01 mm (minor axis) versus 2.61 mm (major axis). Interobserver correlation was highest for sac measurements both in 2D minor axis (ICC=0.8990) and 3D (ICC=0.9518).

CONCLUSIONS

Minor axis measurements on axial CT scan can substitute for diameters obtained from 3D reconstructions in most clinical situations.

Duplex ultrasound imaging with an ultrasound contrast agent: the economic alternative to CT angiography for aortic stent graft surveillance

The use of endovascular stent graft repair for aortic aneurysmal disease has become increasingly common, with the added requirement for close postoperative surveillance to detect the presence of endoleaks or graft migration. The most commonly used technique for surveillance is computed tomography (CT) angiography, with the need for intravenous contrast posing 1 limitation in those patients with renal dysfunction and the cost of this testing presenting an economic limitation. Early results of duplex imaging in the authors' Vascular Laboratory using an intravenous ultrasound contrast agent have shown sensitivity and specificity equivalent to those of CT angiography, with no evidence of any related morbidity. They have evaluated the cost effectiveness of using duplex ultrasound imaging as the primary surveillance technique for postoperative follow-up in aortic stent graft patients. Surveillance protocols now require that 8 follow-up examinations be performed in the first 3 years after stent graft placement. The charges for CT angiography in their institution average 2,779 dollars per study, for a 3-year total of 22,232 dollars per patient. The charges for aortic duplex ultrasound average 525 dollars per study, with a 3-year total of 4,200 dollars per patient. Adding the cost of routine abdominal radiographs to confirm stent graft position (147 dollars per study) would bring this 3-year total to 5,376 dollars, a savings of 16,856 dollars per patient. For every 100 patients who are followed up after stent graft placement, this represents a 3-year savings of more than 1.6M dollars. Promising early results of duplex ultrasound imaging with an intravenous contrast agent show sensitivity and specificity equivalent to those of CT angiography in detecting aneurysm size and graft endoleaks or other hemodynamic abnormalities. If these results can be demonstrated in larger patient series, this technique should become the method of choice for stent graft surveillance, for it offers very significant economic advantages and avoids the complications of intravenous contrast-induced renal dysfunction.

Guidelines for the treatment of abdominal aortic aneurysms. Report of a subcommittee of the Joint Council of the American Association for Vascular Surgery and Society for Vascular Surgery

Decision-making in regard to elective repair of abdominal aortic aneurysms (AAA) requires careful assessment of factors that influence rupture risk, operative mortality, and life expectancy. Individualized consideration of these factors in each patient is essential, and the role of patient preference is of increasing importance. It is not possible or appropriate to recommend a single threshold diameter for intervention which can be generalized to all patients. Based upon the best available current evidence, 5.5 cm is the best threshold for repair in an "average" patient. However, subsets of younger, good-risk patients or aneurysms at higher rupture risk may be identified in whom repair at smaller sizes is justified. Conversely, delay in repair until larger diameter may be best for older, higher-risk patients, especially if endovascular repair is not possible. Intervention at diameter <5.5 cm appears indicated in women with AAA. If a patient has suitable anatomy, endovascular repair may be considered, and it is most advantageous for older, higher-risk patients or patients with a hostile abdomen or other technical factors that may complicate standard open repair. With endovascular repair, perioperative morbidity and recovery time are clearly reduced; however, there is a higher reintervention rate, increased surveillance burden, and a small but ongoing risk of AAA rupture. There is no justification at present for different indications for endovascular repair, such as earlier treatment of smaller AAA. Until long-term outcome of endoluminal repair is better defined and results of randomized trials available, the choice between endovascular and open repair will continue to rely heavily on patient preference.

Intravascular ultrasound aids in the performance of endovascular repair of abdominal aortic aneurysm

PURPOSE

The purpose of this retrospective review was to assess the accuracy of aortic measurements with intravascular ultrasound scan (IVUS) compared with computed tomographic (CT) scan and to assess the role of IVUS in the performance of endovascular repair of abdominal aortic aneurysms (AAAs).

METHODS

Seventy-eight patients undergoing repair of AAA with the AneuRx stent graft (Medtronic AVE, Inc, Santa Rosa, Calif) underwent measurement with CT scan and IVUS. The initial selection of stent graft size was made on the basis of the CT scan measurements, but the final decision for size was made on the basis of the IVUS measurements. Standard measurements of a phantom tube obtained with IVUS, CT scan, and digital caliper were also compared.

RESULTS

IVUS measurements of the phantom standard agreed closely with CT scan measurements. However, stent graft size initially selected with CT measurement was altered in 28% of cases on the basis of intraoperative IVUS measurements. No type I endoleaks were encountered in our series, and no aortic cuffs were necessary for endoleak repair.

CONCLUSION

IVUS accurately measures the aorta for selection of stent grafts for endovascular repair of AAA and may prevent type I endoleaks and remedial procedures for their repair.

Technical success from endovascular aneurysm repair in the post-marketing era: a multicenter prospective trial

Evaluation of post-marketing success with the Ancure Endovascular Graft (AEG) was accomplished by review of a multicenter, prospective trial involving 46 centers and 163 patients. A second cohort of patients (n = 350) treated with the AEG under a controlled-use interval prior to the prospective trial was simultaneously evaluated. Technical success in both groups of patients (96.9% and 97.4%, respectively) was similar to what was reported in pre-market clinical trials. Operative implantation complications unique to the AEG included graft limb stenosis/occlusion in 35.6 and 31.4%, contralateral pull wire being caught on hooks in 33.7 and 28%, failure to seal (type I endoleak) in 17.2 and 18.3%, jacket guard being stuck in 12.9 and 11%, contralateral wire being stuck in 6.8 and 7.1%, high jacket retraction force in 16 and 8.5%, and inability to retract jacket in 1.8 and 0.5% of patients involved in the multicenter trial and controlled-use interval, respectively. One of four patients undergoing conversion in the prospective trial had graft misdeployment as a mode of failure. Three were converted for access failure. The 30-day mortality rate in the prospective trial was 3.7%. Interventions to resolve implantation-related events included stenting, guide catheter manipulations, wire exchanges, and delivery catheter disassembly. These interventions were successful in virtually every case. Open surgical procedures were not needed to correct these operative problems. Results from this study demonstrate excellent technical success with the AEG in the post-market era. Interventions to resolve implantation complications, when utilized, are highly successful in facilitating AEG implantation and providing technical success.

Endovascular treatment of aneurysmal disease

Endovascular repair of abdominal aortic aneurysm using stent grafts that are delivered intraluminally by catheters is a less invasive alternative to open surgical repair. Endovascular surgery has been studied for over a decade, and early results are comparable to open repair. With extended follow-up care, however, postoperative complications and graft failures have been reported in some patients, resulting in reintervention, conversion to open repair, and death. The high incidence of secondary interventions causes some researchers to question the durability of endograft repair and emphasizes the need for detailed long-term follow-up care. This article describes the evolution of endovascular treatment of abdominal aortic aneurysm from its origin to its current state and discusses the future direction of endovascular therapy.