Outcomes of secondary interventions after abdominal aortic aneurysm endovascular repair

Experimental models of abdominal aortic aneurysms

Despite being a leading cause of death in the West, the pathophysiology of abdominal aortic aneurysms (AAA) is still incompletely understood. Pharmacotherapy to reduce the growth of small AAAs is limited and techniques for repairing aneurysms continue to evolve. Experimental models play a key role in AAA research, as they allow a detailed evaluation of the pathogenesis of disease progression. This review focuses on in vivo experimental models, which have improved our understanding of the potential mechanisms of AAA development and contributed to the advancement of new treatments.

AAA stent-grafts: past problems and future prospects

Endovascular aneurysm repair (EVAR) has quickly gained popularity for infrarenal abdominal aortic aneurysm repair during the last two decades. The improvement of available EVAR devices is critical for the advancement of patient care in vascular surgery. Problems are still associated with the grafts, many of which can necessitate the conversion of the patient to open repair, or even result in rupture of the aneurysm. This review attempts to address these problems, by highlighting why they occur and what the failings of the currently available stent grafts are, respectively. In addition, the review gives critical appraisal as to the novel methods required for dealing with these problems and identifies the new generation of stent grafts that are being or need to be designed and constructed in order to overcome the issues that are associated with the existing first- and second-generation devices.

Aortic aneurysm surgery: problems and innovations

A long way was traveled since the first surgery was performed for the treatment of abdominal aortic aneurysm. Throughout this time, several innovations have been created in order to reduce the invasiveness of the surgical procedures and to improve their safety and durability. This review discusses the major and recent advances on aortic aneurysm interventions, including, the endovascular aortic repair, the laparoscopic aortic surgery, the conventional hybrid and endovascular techniques, combined laparoscopic and endovascular techniques, as well as future prospects for both thoracic and abdominal aorta. Faced with so many changes and developments, modern vascular surgeons must keep their minds open to innovations and should develop comprehensive training with different techniques, to provide the best therapeutic option for their patients.

Endovascular treatment of abdominal aortic aneurysms in high-surgical-risk patients

Background: Following the publication of a prospective randomized trial (Endovascular Aneurysm Repair Trial 2 - EVAR2) that questioned the benefits of endovascular repair of abdominal aortic aneurysms (AAA) in high-surgical-risk patients, we decided to analyze our initial and long-term results with endovascular AAA repair in this patient population. Objective: To evaluate the operative mortality, long-term survival, frequency of secondary operations, outcome of the aneurysm sac, primary and secondary patency rates, and rupture rate after aortic stent-graft placement in high-surgical-risk patients. Methods: From April 2002 to February 2008, 40 high-surgical and anesthetic risk patients with an AAA managed by a bifurcated aortic endograft were entered in a prospective registry. Data concerning diagnosis, operative risk, treatment and follow-up were analyzed in all patients Results: Twenty-four Excluder® and 16 Zenith® stent-grafts were successfully implanted. Thirty patients (75%) were classed ASA III and 10 (25%) were ASA IV. Mean aneurysm diameter was 64 mm. Operative mortality was 2.5%. Two patients required reintervention during the mean follow-up of 28.5 months. Survival rate at 3 years was 95%. There were four endoleaks, one case of endotension, and one endograft limb occlusion. Primary and secondary patency rates at 3 years were 97.5 and 100%, respectively. There were no ruptures. Conclusions: Initial and long-term results with endovascular treatment of AAA in high-surgical-risk patients were satisfactory, and appear to justify such approach for this patient population.

Secondary Endovascular and Conversion Procedures for Failed Endovascular Abdominal Aortic Aneurysm Repair: Can We Still Be Optimistic?

The purpose of this study was to evaluate the incidence, etiology, and outcome of secondary endovascular and “open” conversion procedures after failed endovascular abdominal aortic aneurysm repair (EVAR). From January 1997 until December 2005, 625 patients with an infrarenal abdominal aortic aneurysm were treated by elective EVAR, with 98.7% ( n = 617) primary EVAR success. The mean follow-up of the 617 patients was 46.7 ± 11.2 months. One hundred of these patients (16.2%) required secondary endovascular or peripheral procedures, and 39 (6.3%) patients underwent a secondary abdominal conversion. There were 5 acute conversions (0.8%) and 34 elective conversions (5.5%). The pre-EVAR anatomic suitability data, the main cause of the secondary procedure, and stent graft type were compared between patients with primary EVAR success, patients in need of a secondary endovascular or peripheral procedure, and patients with abdominal conversion. The overall main causes for reinterventions were proximal migration ( n = 60; 9.7%), progressive kinking of the stent graft ( n = 59; 9.6%), and late type III endoleak ( n = 12; 1.9%). Multivariate logistic regression analysis showed that factors significantly correlated with secondary procedures were the abdominal aortic aneurysm's maximum diameter, the proximal neck's width and length, and particularly the commercial withdrawal of the stent graft ( p < .001). The morbidity and mortality rates of secondary endovascular or peripheral interventions were 0%. The mortality rate of acute secondary conversions was 20% ( n = 1) and of elective secondary conversions was 8.8% ( n = 3). The morbidity rates for acute and elective conversions were 0% and 65%, respectively. The aneurysm-related mortality rate in our series was below 1%. Abdominal conversion surgery still carries a high mortality rate, but the overall EVAR-related mortality rate remains low. Early pitfall detection and proper reintervention are crucial to long-term EVAR success.

Remodeling of the aortic neck with a balloon-expandable stent graft in patients with complicated neck morphology

Graft migration and other device-related problems are more frequent in abdominal aortic aneurysm (AAA) patients with a complicated neck. We wanted to evaluate the performance of a balloon-expandable stent graft in these cases. Complicated aortic neck morphology was defined as a combination of short (<15 mm) and angulated (>45 degrees) necks with or without circumferential thrombus. Severe aortic angulation was defined as less than 120 degrees. During a 24-month period, 18 consecutive patients with complicated neck anatomy were treated with the Vascular Innovations (VI)-Datascope balloon-expandable endograft. In two patients, a balloon-expandable cuff was implanted to remodel the neck prior to insertion of a bifurcated endograft (Excluder, W.L. Gore & Associates, Flagstaff, AZ). Demographic, procedural, and outcome data were collected prospectively and retrospectively analyzed. All patients had preoperative computed tomographic (CT) angiography to determine aortic neck angulation and were followed with duplex ultrasonography and CT every 3 and 6 months postoperatively to assess aortic neck and sac dilatation, as well as device migration. The VI-Datascope graft consists of an aortounifemoral polytetrafluoroethylene (PTFE) graft sutured to a proximal balloon-expandable stent. The length of the graft is 40 cm; thus, the distal end of the graft always protrudes through the ipsilateral arteriotomy and can be cut to an appropriate length for each patient. The covered portion of the graft was deployed just below the level of the lowest renal artery. The proximal bare metal stent was deployed in the suprarenal area. An endoluminal hand-sewn anastomosis was performed between the aortounifemoral limb and the distal external iliac or the common femoral arteries. An occluder device was placed in the contralateral common iliac artery to prevent retrograde perfusion of the aneurysm. A femorofemoral 8 mm Dacron graft bypass was then performed to establish flow to the contralateral extremity and pelvis. Using this approach, remodeling and straightening of angulated aortic neck morphology were achieved in all cases, including in 44% of patients with severe aortic neck angulation. The average follow-up period was 11.5 months (4-21 months). There was one early occlusion (<30 days after implantation) of the PTFE limb requiring thrombectomy and one late occlusion (6 months after implantation) requiring thrombectomy and implantation of a Viabahn stent graft (W.L. Gore & Associates). Scheduled CT scans did not show any graft migration or proximal neck dilatation. Neither neck dilatation nor endograft migration was observed with the balloon-expandable stent graft. In patients with complicated aortic neck morphology, balloon-expandable stent grafts such as the VI-Datascope graft provide more secure fixation and better long-term outcomes compared with the more commonly used self-expanding endografts.

The Durability of Evar — What are the Evidence and Implications on Follow-Up?

Background and Aims:

To investigate the durability of EVAR and to explore the evidence for follow-up investigations. Furthermore, to study the patients' impressions of follow-up investigations, and how complications and secondary procedures influence cost-effectiveness.

Material and Methods:

263 patients were treated by EVAR from february 1995-february 2007. The series is divided into two groups with the year 2000 as a cut-off point since a new generation of stent grafts was then introduced. Early and late complications and secondary procedures were recorded. A questionnaire study was performed to investigate the patients' views on the follow-up program.

Results:

There was a significant reduction of complications from period I to period II, which was also reflected in the reduction of secondary procedures. Freedom from secondary procedures were 47% and 93% at 5 years follow-up in the two periods, respectively. In phase II, 7.5% of the patients needed a secondary procedure. Limb extension and femoro-femoral bypass were the most common procedures. Since late complications still occur, and can be unpredictable, a follow-up program is necessary. The vast majority of the patients tolerated the follow-up program well.

Conclusions:

Although the number of complications following EVAR has decreased significantly over the years, a thorough follow-up program is still necessary. This follow-up regime is well tolerated by the patients. Reduction of secondary procedures is important to improve the cost-effectiveness of EVAR.

Chronically impaired endothelial vasoreactivity following oversized endovascular introducer sheath placement in porcine iliac arteries: implications for endovascular therapy

The conventional endovascular aortic aneurysm procedure entails the placement of oversized introducer sheaths in relatively normal ileofemoral arteries to allow the delivery and deployment of endovascular prosthesis. Endoluminal manipulation with passage of oversized endoluminal devices can lead to endothelial denudation, resulting in impaired cellular function. The purpose of this study was to assess the time course of endothelial function with vasoreactivity following oversized endovascular sheath insertion ranging from 1 day to 16 weeks in normal porcine iliac arteries. Following oversized introducer sheath placement in bilateral iliac arteries, vasoreactivity was tested using both endothelium-dependent and -independent vasodilators. Intravascular ultrasonography showed a significant reduction in the luminal area at 12 and 16 weeks. This was similarly supported by morphometric analysis, which showed increased medial thickness with an elevated intima to media ratio at the same time course. Endothelium-dependent relaxation to bradykinin, calcium ionophore A23187, serotonin, and adenosine diphosphate all uniformly displayed attenuated endothelial dysfunction at all time points when compared with the control group. In contrast, endothelium-independent relaxation showed a decreased vasoresponsiveness at 4 weeks. In conclusion, this study underscored the detrimental and chronic endothelial dysfunction in a normal artery caused by oversized introducer sheath placement. Chronically impaired endothelial function may play a role leading to iliofemoral artery thrombosis or late occlusion, which were well-recognized adverse events following endovascular aneurysm procedures. Our study underscores the importance of appropriate patient selection to minimize potential sheath oversize and endograft device miniaturization to avoid vessel wall injury and maintain vasoreactivity.

Long-term durability of open abdominal aortic aneurysm repair

OBJECTIVE

In multiple comparisons of open vs endovascular (EVAR) repair of abdominal aortic aneurysms, the prior assumption that open repair produced superior durability has been challenged by advocates of EVAR. Although focus on EVAR reintervention has been intense, few contemporary studies document late outcomes after open repair; this was the goal of this study.

METHODS

From January 1994 to December 1998 (chosen to ensure a minimum 5-year follow-up), 540 patients underwent elective open repair. Surveillance imaging (computed tomographic and magnetic resonance imaging scans) was obtained for 152 (57%) of the 269 patients who remained alive at a mean follow-up of 87 months. Study end points included freedom from graft-related interventions and aneurysm-related and overall survival (Kaplan-Meier test); factors predictive of these end points were determined by multivariate analysis.

RESULTS

The mean age at operation was 73 years. A total of 76% of patients were male; 11% had renal insufficiency (creatinine > or =1.5 mg/dL), and 13% had chronic obstructive pulmonary disease. The aortic cross-clamp position was suprarenal in 135 (25%) patients, and 284 (53%) of patients had bifurcated grafts placed. Operative mortality (30 days) was 3%, and the median length of hospital stay was 7 days. Postoperative complications occurred in 68 (13%) patients. Predictors of postoperative complications included a history of myocardial infarction (hazard ratio [HR], 2.0; P = .01) and renal insufficiency (HR, 2.5; P = .02). The mean follow-up for all patients was 87 months. Actuarial survival was 70.7% +/- 2% and 44.3% +/- 2.4% at 5 and 10 years, respectively. Negative predictors of long-term survival included advanced age (HR, 1.1; P < .001), history of myocardial infarction (HR, 1.37; P = .02), and renal insufficiency (HR, 1.5; P = .04). Freedom from graft-related reintervention was 98.2% +/- 0.8% and 94.3% +/- 3.4% at 5 and 10 years, respectively. There were 13 late graft-related complications in 11 (2%) patients (mean follow-up, 7.2 years). Findings included seven anastomotic pseudoaneurysms (five were repaired), four graft limb occlusions, and two graft infections. Aneurysms were identified in noncontiguous arterial segments in 68 (45%) of 152 patients, most of which involved the iliac arteries and required no treatment because of small size. Late aortic aneurysms proximal to the repair were identified in 24% of patients, and 29 (19%) patients had multiple late synchronous aneurysms.

CONCLUSIONS

Open repair remains a safe and durable option for the management of abdominal aortic aneurysms, with an excellent associated 10-year survival in patients who undergo operation at 75 years of age or younger. In addition, the freedom from graft-related reintervention is superior to that of EVAR. Finally, continued surveillance after open repair is appropriate and should be directed toward the detection of other aneurysms.

Endovascular Repair of Infrarenal Abdominal Aortic Aneurysms in High-Risk-Surgical Patients

PURPOSE

Following the publication of a prospective randomized trial (EVAR2) that questioned the benefit of endovascular repair of abdominal aortic aneurysms (AAA) for high-surgical-risk patients, we evaluated our own initial and long-term results with endovascular AAA repair for this patient population.

MATERIAL AND METHODS

Between January 2000 and December 2005, 115 patients with an AAA managed by an aortic endograft were entered in a registry. Data concerning diagnosis, operative risk, treatment, and follow-up were analyzed on an intention-to-treat basis for all patients considered to be poor candidates for surgery. Patients with a ruptured AAA and those who were good surgical candidates were excluded from analysis. The main goal was evaluation of the operative mortality and the long-term survival of these patients. Secondary goals were determination of the frequency of secondary operations, the outcome of the aneurysm sac, and primary and secondary patency rates after aortic endograft placement.

RESULTS

A total of 92 high-surgical-risk patients treated by an endograft were entered in this study. Sixty-seven patients (73%) were classed ASA III and 18 (20%) were ASA IV (20%). Mean aneurysm diameter was 58 mm+/-9 mm. The technical success rate was 99%. Operative mortality was 4.3% (4 cases). Four patients required re-intervention during the mean follow-up of 18 months. The survival rate at 3 yr was 85%. One type I endoleak (1%) and 9 type II endoleaks (9.7%) occurred during the follow-up period. Primary and secondary patency rates at 3 yr were respectively 96% and 100%.

CONCLUSION

Our initial and long-term results with endograft repair of AAA in high-surgical-risk patients were satisfactory. These results appear to justify endovascular repair for this patient population.

Limb Graft Occlusion Following EVAR: Clinical Pattern, Outcomes and Predictive Factors of Occurrence

INTRODUCTION

We reviewed our experience with limb occlusion after EVAR in order (1) to assess the clinical pattern and treatment options (2) to assess outcomes and (3) to identify predictive factors of occurrence.

MATERIALS AND METHOD

Between 1995 and 2005, 460 AAA patients were electively treated with a variety of commercially available stent grafts. There were 369 bifurcated and 91 aortouniiliac grafts (829 limbs). Follow-up included physical examination, plain X-ray, Duplex ultrasonography, and spiral computed tomographic scans at 1, 6, 12 months and annually thereafter. All pertinent data were collected prospectively and analysed retrospectively. The follow-up period ranged from Day 0 to 104 months, with a median follow-up of 23.4 months.

RESULTS

36 limbs in 33 patients (7.2%) occluded between Day 0 and 71 months (average: 9.5 months) after EVAR. Presentation was acute ischemia in 11 cases, rest pain in 9, claudication in ten. Four occlusions remained asymptomatic and two occurred intraoperatively. Treatment was femoro-femoral cross-over graft in 19 cases, axillo-femoral bypass in three, thrombectomy and stent in three, thrombolysis and stent in nine, and conservative in two. One patient (3%) died of multiple organ failure after thrombolysis. There was no amputation. Reocclusions occurred in two patients (6.1%). Multivariate logistic regression showed that kinking (odds ratio [OR] 11.9; confidence interval [CI] 3.39-42.1; p=0.0001), first graft generation (OR 2.87; CI 1.25-6.62; p=0.017) and younger age (OR 1.05; CI 1.00-1.09; p=0.034) were independently related to the occurrence of graft limb occlusion.

CONCLUSION

Acute graft limb occlusion is not rare after EVAR. The frequency of limb occlusion has declined with current stent grafts generation. Although surgery and endovascular treatments are efficient and safe, development of a graft limb kink should lead to aggressive pre-emptive treatment to prevent occlusion.

Long-term postplacement cost after endovascular aneurysm repair

BACKGROUND

Previous studies have demonstrated that the initial hospital cost associated with endovascular aneurysm repair (EVAR) is approximately $20,000. However, the cost of long-term surveillance and secondary procedures is poorly characterized.

METHODS

Between December 1998 and June 2006, 259 patients underwent EVAR for infrarenal aneurysms at a single institution. Follow-up costs were calculated using a relative value unit based hospital cost accounting system, which incorporates departmental direct and indirect costs. Institutional overhead costs were included using a conversion factor. Costs for professional services were determined by a cost-to-charge ratio, and outpatient visits were calculated with a time-based formula. Year 2006 costs were applied to prior years. To minimize costs associated with the early learning curve, the initial 50 EVAR patients between December 1995 and 1998 were excluded. Patients with <1 year follow-up were also excluded. Data are expressed as mean +/- standard error.

RESULTS

The mean follow-up after EVAR for 136 patients was 34.7 +/- 1.8 months. The cumulative 5-year postplacement cost per patient was $11,351. The 27 patients (19.9%) who required secondary procedures had a 5-year cumulative cost of $31,696 compared with $3668 for 109 patients without secondary procedures (8.6-fold increase, P < .05). The 5-year cost for patients with endoleak was $26,739 compared with $5706 for those without endoleak (4.7-fold increase, P < .05). Overall, major cost components were 57.4% for secondary procedures and 32.5% for radiologic studies.

CONCLUSIONS

During a 5-year period, the postplacement cost of EVAR increases the global cost by 44%. The subgroups of patients with endoleaks and those requiring secondary procedures generate a disproportionate share of postplacement costs. Efforts at minimizing cost should emphasize technical and device modifications aimed at reducing endoleaks and the need for secondary procedures.

Treatment of type II endoleak with a transcatheter transcaval approach: Results at 1-year follow-up

PURPOSE

This study assessed the feasibility and mid-term outcomes in the treatment of type II endoleak using transcatheter transcaval embolization (TTE).

METHODS

During an 8-month period, 12 patients underwent TTE. After direct transcaval puncture of the aneurysm sac, embolization was performed by injecting thrombin and placing coils. Systemic and intrasac pressures were recorded throughout the entire procedure. Computed tomography (CT) scans were performed at 24 hours, 30 days, 6 months, and 1 year after TTE to evaluate endoleaks and changes in sac diameter. Technical success was defined as the feasibility of the procedure; clinical success was defined as no evidence of leaks during the follow-up evaluation.

RESULTS

TTE was feasible in 11 of 12 patients (technical success 92%). The mean systemic pressure was 117 mm Hg. The mean intrasac pressure before embolization was 75 mm Hg (range, 39 to 125 mm Hg), 16.5 mm Hg (range, 7 to 40 mm Hg) in 10 patients after embolization, and it increased in one patient. CT scans at 24 hours showed stable contrast medium inside the sac in 10 patients. Only minor complications were observed during follow-up. At the 1-year follow-up, no recurrence of leaks was noted, and sac diameter was reduced in 10 of 11 patients. As a result, TTE clinical success was obtained in 10 (83%) of 12 patients.

CONCLUSION

TTE appears to be a feasible technique for the complete exclusion of type II endoleaks. Technical and clinical successes are comparable with other treatment strategies, and TTE should be considered an alternative to direct translumbar puncture of the aneurysm sac.

Use of dynamic computed tomography to evaluate pre- and postoperative aortic changes in AAA patients undergoing endovascular aneurysm repair

PURPOSE

To utilize dynamic computed tomographic angiography (CTA) on pre- and postoperative endovascular aneurysm repair (EVAR) patients to characterize cardiac-induced aortic motion within the aneurysm neck, an essential EVAR sealing zone.

METHODS

Electrocardiographically-gated CTA datasets were acquired utilizing a 64-slice Philips Brilliance CT scanner on 15 consecutive pre- and postoperative AAA patients. Axial pulsatility measurements were taken at 2 clinically relevant levels within the aneurysm neck: 2 cm above the highest renal artery and 1 cm below the lowest renal artery. Changes in aortic area and diameter were determined.

RESULTS

Significant aortic pulsatility exists within the aneurysm neck during the cardiac cycle. Preoperative aortic area increased significantly, with a maximum increase of up to 12.5%. The presence of an endograft did not affect aortic pulsatility (p=NS). Postoperative area also changed significantly during a heart cycle, with a maximum increase of up to 14.5%. Diameter measurements demonstrated an identical pattern, with significant pre- and postoperative intracardiac pulsatility within and above the aneurysm neck (p<0.05). An increase in maximum diameter change up to 15% was evident.

CONCLUSION

Patients undergoing EVAR experience aortic diameter changes within and above the aneurysm neck. The presence of an endograft does not abrogate this response to intracardiac pressure changes. Static CT imaging may not adequately identify patients with large aortic pulsatility, potentially resulting in endograft undersizing, stent-graft migration, intermittent type I endoleaks, and poor patient outcomes. The current standard regime of 10% to 15% oversizing based on static CT may be inadequate for some patients.

The influence of aortic cuffs and iliac limb extensions on the outcome of endovascular abdominal aortic aneurysm repair

BACKGROUND

In a proportion of patients with an endovascular abdominal aortic aneurysm repair (EVAR), aortic cuffs or iliac graft limb extensions are required to enhance sealing or to fix the position of the device. This requirement arises when these goals are not primarily obtained with the basic stent-graft configuration. The aim of this study was to assess the influence of the use of endograft extensions during the primary EVAR procedure on the short- and long-term outcome.

METHODS

The study was based on the data of the EUROSTAR registry. Patient and anatomic characteristics, data regarding the procedure, postoperative complications, and the mortality of patients undergoing EVAR were retrieved from the database. Patients were divided into three groups: (1) no extensions, (2) proximal aortic cuffs, and (3) iliac limb extensions. Logistic regression and Cox proportional hazards models were used to compare significant influences of the use of cuffs or extensions on different outcomes relative to control patients, adjusted for patient and anatomic factors.

RESULTS

The overall cohort comprised 6668 patients: 4932 (74.0%) without extensions, 259 (3.9%) with an aortic cuff, and 1477 (22.2%) with an iliac endograft extension. Both the 30-day (2.3%-3.9%) and the all-cause mortality rates (23%-27% at 4 years) were similar in the three study groups. The use of proximal cuffs or iliac extensions did not have an effect on the incidence of endoleaks of any type (24%-32% at 4 years). The incidences of device kinking (P = .0344) and secondary transfemoral interventions (P = .0053) during follow-up were increased in patients in whom iliac limb extensions were used. In patients with aortic cuffs, no significant associations with altered outcome were observed.

CONCLUSIONS

The use of iliac graft limb extensions at EVAR was associated with a higher incidence of kinking and secondary transfemoral interventions, whereas proximal aortic cuffs did not influence outcome.

Long-term outcomes after endovascular abdominal aortic aneurysm repair: the first decade

OBJECTIVE

The proper role of endovascular abdominal aortic aneurysm repair (EVAR) remains controversial, largely due to uncertain late results. We reviewed a 12-year experience with EVAR to document late outcomes.

METHODS

During the interval January 7, 1994 through December 31, 2005, 873 patients underwent EVAR utilizing 10 different stent graft devices. Primary outcomes examined included operative mortality, aneurysm rupture, aneurysm-related mortality, open surgical conversion, and late survival rates. The incidence of endoleak, migration, aneurysm enlargement, and graft patency was also determined. Finally, the need for reintervention and success of such secondary procedures were evaluated. Kaplan-Meier and multivariate methodology were used for analysis.

RESULTS

Mean patient age was 75.7 years (range, 49-99 years); 81.4% were male. Mean follow-up was 27 months; 39.3% of patients had 2 or more major comorbidities, and 19.5% would be categorized as unfit for open repair. On an intent-to-treat basis, device deployment was successful in 99.3%. Thirty-day mortality was 1.8%. By Kaplan-Meier analysis, freedom from AAA rupture was 97.6% at 5 years and 94% at 9 years. Significant risk factors for late AAA rupture included female gender (odds ratio OR, 6.9; P = 0.004) and device-related endoleak (OR, 16.06; P = 0.009). Aneurysm-related death was avoided in 96.1% of patients, with the need for any reintervention (OR, 5.7 P = 0.006), family history of aneurysmal disease (OR, 9.5; P = 0.075), and renal insufficiency (OR, 7.1; P = 0.003) among its most important predictors. 87 (10%) patients required reintervention, with 92% of such procedures being catheter-based and a success rate of 84%. Significant predictors of reintervention included use of first-generation devices (OR, 1.2; P < 0.01) and late onset endoleak (OR, 64; P < 0.001). Current generation stent grafts correlated with significantly improved outcomes. Cumulative freedom from conversion to open repair was 93.3% at 5 through 9 years, with the need for prior reintervention (OR, 16.7; P = 0.001) its most important predictor. Cumulative survival was 52% at 5 years.

CONCLUSIONS

EVAR using contemporary devices is a safe, effective, and durable method to prevent AAA rupture and aneurysm-related death. Assuming suitable AAA anatomy, these data justify a broad application of EVAR across a wide spectrum of patients.

Treatment of type II endoleaks after endovascular repair of abdominal aortic aneurysms: transcaval approach

The purpose of the note is to describe a new technique for type II endoleak treatment, using an alternative approach through femoral venous access. Three patients who developed type II endoleak after endovascular repair of abdominal aortic aneurysm were treated with direct transcaval puncture and embolization inside the aneurysm sac. The detailed technique is described. All patients were treated without any complications and discharged 48 hours after the treatment. At 1 month follow-up the computed tomograph scan did not show a recurrence of a type II endoleak. The management of patients with type II endoleak is a controversial issue and different techniques have been proposed. We suggest an alternative technique for type II endoleak treatment. The feasibility and the advantages of this approach can offer new possibilities for the diagnosis as well as for the treatment of this complication.

Surgical corrections of endovascular aneurysms: repair complications

The authors describe their experience with the use of 21 open surgical corrections after endovascular abdominal aneurysm repair, reporting the frequency, type and outcome of these procedures in their group of 165 patients treated during a 10-year period.

Implant Degradation and Poor Healing After Endovascular Repair of Abdominal Aortic Aneurysms: An Analysis of Explanted Stent-Grafts

PURPOSE

To study explanted stent-grafts to achieve a better understanding of the mechanisms of failure after endovascular treatment of abdominal aortic aneurysms (AAA).

METHODS

Twelve stent-grafts were harvested at autopsy (n=3) or during surgical conversion (n=9). Device alterations were investigated by macroscopic examination, radiography, and surface analysis techniques. Healing around the implants was studied via histology and immunohistochemistry, with particular attention to the stent-graft/tissue interface.

RESULTS

Degradation was more important with Vanguard stent-grafts (off the market) than with AneuRx and Talent stent-grafts, but rupture of nitinol wires and poor surface finish in Talent stent-grafts raise concern about their corrosion resistance and long-term stability. Poor healing was observed around stent-grafts even after several years of implantation, with absence of vascular smooth muscle cells, fibroblasts, and collagen formation. In addition to the well-known foreign body reaction around the graft, numerous polymorphonuclear cells characteristic of the first step of healing were present in tissues around stent-grafts retrieved at surgical conversion. Factors explaining the lack of tissue organization around stent-grafts are discussed.

CONCLUSION

The long-term stability of implants remains a concern and requires more transparency from manufacturers regarding the surface properties of their devices. Lack of neointima formation impairs biological fixation of the implant to the vessel wall, leading to possible endoleaks and migration. New-generation stent-grafts promoting biological fixation should be developed to improve clinical outcomes of this minimally invasive treatment.

Translumbar Type II Endoleak Repair Using Angiographic CT

Translumbar embolization of type II endoleaks after endovascular abdominal aneurysm repair has been proved to be effective. One challenge of this approach is the choice of the most suitable image guiding modality. For needle placement, cross-sectional imaging under computed tomographic (CT) guidance is preferable. For embolization, fluoroscopy is the modality of choice for most interventionalists. A new technology can acquire CT-like images by rotating an angiographic, flat-panel detector of a C-arm around the patient. This technology allows a combination of fluoroscopic and CT guidance within the angiographic suite. The authors describe the successful use of a combination of fluoroscopy and angiographic CT in three cases of translumbar type II endoleak embolization.

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.

Laparoscopy-assisted abdominal aortic aneurysm repair: Early and middle-term results of a consecutive series of 122 cases

BACKGROUND

Endoaneurysmorrhaphy with intraluminal graft placement, described by Creech, is the gold standard for abdominal aortic aneurysm (AAA) repair. Endovascular aneurysm repair has gained popularity for its minimal invasiveness and satisfying short-term results, but there are still many concerns about the long-term success of the procedure. Since 1998, laparoscopic surgery has been proposed for AAA treatment. The potential benefits of a minimally invasive procedure reproducing the endoaneurysmorrhaphy results over time have been advocated. In our experience, hand-assisted laparoscopic surgery (HALS) has been routinely used for the open-surgery transperitoneal/retroperitoneal approach and for endovascular aneurysm repair. After 4 years, we are able to define the early and middle-term results of such laparoscopic-assisted treatment.

METHODS

From October 2000 to March 2004, 604 consecutive nonurgent AAAs were treated at our institution. Of these, 122 (20.2%) were treated by HALS. Exclusion criteria for HALS were hostile abdomen (previous major abdominal or aortic surgery), bilateral diffuse common iliac and/or hypogastric aneurysms, massive aortoiliac calcifications, and severe cardiac (ejection fraction <35%) and respiratory (P(O2) <60 mm Hg or carbon dioxide >50 mm Hg) insufficiency. Juxtarenal and proximal iliac aneurysms were not a contraindication, nor was obesity. In all patients, we performed a minilaparotomy (7-8 cm) both for laparoscopic hand-assisted dissection and for endoaneurysmorrhaphy. All perioperative data were prospectively recorded. Follow-up consisted of ultrasonography and clinical evaluation after 6 and 12 months and then every year after surgery.

RESULTS

The mean laparoscopic and total operative times were respectively 64 +/- 32 minutes and 257 +/- 70 minutes, the mean aortic cross-clamping time was 76 +/- 26 minutes, and the mean autotransfused blood volume was 1136 +/- 711 mL. The overall mortality and morbidity were respectively 0% and 12.2%. Morbidity was surgery related in only two cases (bleeding from an ipogastric artery lesion and a leg graft thrombosis). The mean intensive care unit stay was 14.3 +/- 13 hours. Oral food intake was resumed after 27.4 +/- 15 hours, and patients were discharged after a mean of 4.4 +/- 1.7 days. Operative times were not affected by obesity, suprarenal aortic cross-clamping, or aneurysm size. Both concomitant iliac aneurysms and bifurcated graft implantation (related to longer vascular reconstruction) involved significantly longer operative times. The learning curve of the procedure (comparing the first 30 patients with the last 92 patients) led to significantly shorter endoscopic, cross-clamping, and total operative times (P = .000). The mean follow-up was 28.6 +/- 16 months. Three incisional hernias and one case of bowel occlusion were detected. All these cases (3.4%) required laparoscopic treatment.

CONCLUSIONS

The HALS technique is a safe and minimally invasive treatment for AAA; it is useful for limiting the need for conventional open surgery and reducing the length of hospital stay. Despite the lack of randomized studies, HALS seems to be associated with a better postoperative course than standard open surgery. HALS can also be considered as an equivalent of a well-established procedure and as a bridge between open and total laparoscopic surgery.

Initial and Midterm Results for Repair of Aortic Diseases With Handmade Stent Grafts

BACKGROUND

The purpose of this study was to determine the initial and midterm results for repair of thoracic and abdominal aortic diseases using handmade stent-grafts (SGs).

METHODS AND RESULTS

Between 1999 and 2004, 41 consecutive patients (31 patients with thoracic and 10 patients with abdominal aortic disease) underwent endovascular stent-graft repair using handmade SGs. The follow-up averaged 24.8+/-17.6 months. The technical and initial clinical success rates were 82.9% (34/41) and 80.5% (33/41), respectively. Primary type I or III endoleaks occurred in 12.2% (5/41) of the patients. The hospital mortality rate was 4.9% (2/41). Persistent type I or III endoleaks occurred in 9.8% (4/41) and SG migrations occurred in 4.9% (2/41) of the patients. Open surgical conversion was undertaken in 12.2% (5/41) of the patients because of an endoleak and/or migration. The mean change observed in the aneurysm diameter was -6.2+/-10.5 mm, and shrinkage in the diameter occurred in 51.4% (18/35) of the cases. There was 1 patient death because of aneurysm rupture. Neither stent fracture nor graft hole was observed. The overall clinical success rate during follow-up was 78.0% (32/41).

CONCLUSION

The initial and midterm results obtained after repair of the aortic diseases using handmade SGs were considered to be satisfactory. More surgical experience and long-term patient follow-up are both required to further reassess the effect of this treatment.

What Determines and Are the Consequences of Surveillance Intensity after Endovascular Abdominal Aortic Aneurysm Repair?

Follow-up examinations are advised 1, 3, 6, 12, 18, and 24 months and yearly thereafter by the European Collaborating Group on Stent-Graft Techniques for Abdominal Aortic Aneurysm Repair (EUROSTAR). The aim of this study was to evaluate the determinants and consequences of surveillance completeness. Patients who underwent endovascular abdominal aortic aneurysm repair between October 1996 and August 2004 and enrolled in the EUROSTAR registry were analyzed. Two groups were compared: patients who attended all scheduled visits (group A) and those who came infrequently (group B). Odds ratios and hazard rates (HRs) with 95% confidence intervals (CIs) were determined to detect which patient characteristics and complications were associated with follow-up intensity. Of the 4,433 patients, 1,538 (35%) attended all scheduled visits until the end of follow-up (group A). Analysis of patient characteristics demonstrated that intensive visitors were more often smokers, hyperlipemic, and considered unfit for open surgery or general anesthesia. Complications during follow-up, including endoleaks (24% vs. 20%), kinking (3.5% vs. 2.5%), and migration (4.9% vs. 3.5%), appeared significantly more frequently in group A. Despite intensive follow-up of this category, still a greater proportion died (12% vs. 9%, adjusted HR = 1.5, 95% CI 1.2-1.8). After 84 months of follow-up, the cumulative survival rates in groups A and B were 71% and 74%, respectively (p < 0.0001). It seems that follow-up intensity was based on baseline patient characteristics. High-risk patients had, despite more intensive surveillance, still more complications after adjustment for patient, morphological, and center-specific characteristics. Further assessment is indicated to evaluate the effectiveness of different frequencies of surveillance visits.

Endovascular Aneurysm Repair versus Open Aneurysm Repair: Comparison of Treatment Outcome and Procedure-Related Reintervention Rate

We conducted a retrospective study to compare treatment outcome and procedure-related reintervention rates of endovascular aneurysm repair (EVAR) with those of open repair. Clinical and radiological data of patients treated at the Rijnstate Hospital (Arnhem, The Netherlands) for nonsymptomatic aortic abdominal aneurysm during October 1998-January 2004 were reviewed and analyzed for demographic data, aneurysm specifics, comorbid condition status, and perioperative outcome. There were 99 patients treated with EVAR and 116 patients treated with open repair. Significant differences in age were seen between treatment groups, patients under the age of 80 being more likely to have open repair (p < 0.004). The EVAR group consisted of significantly fewer women (p < 0.029). Of seven comorbid conditions, four reached significant differences between treatment groups; patients with ischemic heart disease (p < 0.044), heart failure (p < 0.006), renal failure (p < 0.033), or peripheral arterial disease (p < 0.006) were more likely to have EVAR. Comparison of aneurysm anatomy showed no difference in size between EVAR (mean 57.7 mm, 95% CI 55.9-59.5 mm) and open repair (mean 60.1 mm, 95% CI 57.9-62.3 mm). Significant differences were seen in aneurysm neck length and diameter. Operative outcome showed differences in length of hospital stay (median, EVAR 7 vs. open repair 11 days), 30-day mortality (p < 0.048), postoperative hematoma (p < 0.001), and postoperative pulmonary infections (p < 0.001), all in favor of EVAR. Follow-up of the EVAR group showed a decrease (mean 10 mm, 95% CI 7-14 mm) of aneurysm diameter in 15% of cases during follow-up (mean 18 months, range 1-66). Despite higher age and more comorbidity of patients undergoing EVAR, 30-day mortality, postoperative pulmonary infection rate, and length of hospital stay were lower than for those undergoing open repair. Both EVAR and open repair can be performed on a subset of patients with low mortality, complication, and reintervention rates.

Mid- and long-term device migration after endovascular abdominal aortic aneurysm repair: A comparison of AneuRx and Zenith endografts

BACKGROUND

Freedom from migration is key to the durability of endovascular aneurysm repair (EVAR). This study evaluates the mid- and long-term incidence of migration with two different endografts.

METHODS

Between September 1997 and June 2004, 235 patients were scheduled for EVAR with an AneuRx (Medtronic/AVE Inc.) or Zenith (Cook) endograft. Patients with fusiform, infrarenal aneurysms and a minimum 12 months of follow-up were analyzed, for a final cohort of 130 patients. Migration was assessed on axial computed tomography (CT) (2.5 to 3 mm cuts) as the distance from the most caudal renal artery to the first slice containing endograft (AneuRx) or to the top of the bare suprarenal stent (Zenith). Aortic neck diameters were measured at the most caudal renal artery. The initial postoperative CT scan was the baseline. Migration was defined by caudal movement of the endograft at two thresholds, > or =5 mm and > or =10 mm, or any migration with a related clinical event.

RESULTS

Life-table analysis demonstrated AneuRx freedom from migration (> or =10 mm or clinical event) was 96.1%, 89.5%, 78.0%, and 72.0% at 1, 2, 3, and 4 years, respectively. Zenith freedom from migration was 100%, 97.6%, 97.6%, and 97.6% at 1, 2, 3, and 4 years, respectively (P = .01, log-rank test). The stricter 5-mm migration threshold found 67.4% of AneuRx and 90.1% of Zenith patients free from migration at 4 years of follow-up. Twelve out of 14 (85.7%) AneuRx patients (12/14) with migration (> or =10 mm or clinical event) underwent 14 related secondary procedures (13 endovascular, 1 open conversion). The single Zenith patient with migration (> or =10 mm) has not required adjuvant treatment. Mean follow-up was 39.0 +/- 2.3 months (AneuRx) and 30.8 +/- 1.9 months (Zenith, P = .01). Patients with and without migration did not differ in age, gender ratio, aneurysm diameter, and neck diameter. However, initial neck length was shorter in patients with migration (22.1 +/- 2.1 mm vs 31.2 +/- 1.2 mm, P = .02). A subset of patients (21.6%) experienced significant (defined as > or =3 mm) maximum aortic neck dilation. Of the AneuRx patients, > or =3 mm aortic neck dilation affected 30.8% of migrators vs 13.0% of nonmigrators (P = .20).

CONCLUSIONS

Endograft migration is a time-dependent phenomenon affected by both device choice and aortic neck length. A great majority of patients (85.7%) with migration of the AneuRx device ultimately required treatment. A minority of patients experienced aortic neck dilation that could be considered clinically significant. Careful surveillance for migration is an essential component of long-term follow-up after EVAR.

Systematic review of recent evidence for the safety and efficacy of elective endovascular repair in the management of infrarenal abdominal aortic aneurysm

Background

Conventional management of abdominal aortic aneurysm (AAA) is by open repair and is associated with a mortality rate of 2–6 per cent. Endovascular aneurysm repair (EVAR) is an alternative technique first introduced in 1991. A systematic review was undertaken of the evidence for the safety and efficacy of elective EVAR in the management of asymptomatic infrarenal AAA.

Methods

Thirteen electronic bibliographical databases were searched, covering biomedical, health-related, science and social science literature. Outcomes were assessed with respect to efficacy (successful deployment, technical success, conversion rates and secondary intervention rates) and safety (30-day mortality rate, procedure morbidity rates and technical issues—endoleaks, graft thrombosis, stenosis and migration).

Results

Of 606 reports identified, 61 met the inclusion criteria (three randomized and 15 non-randomized controlled trials, and 43 uncontrolled studies). There were 29 059 participants in total; 19 804 underwent EVAR. Deployment was successful in 97·6 per cent of cases. Technical success (complete aneurysm exclusion) was 81·9 per cent at discharge and 88·8 per cent at 30 days. Secondary intervention to treat endoleak or maintain graft patency was required in 16·2 per cent of patients. Mean stay in the intensive care unit and mean hospital stay were significantly shorter following EVAR. The 30-day mortality rate for EVAR was 1·6 per cent (randomized controlled trials) and 2·0 per cent in nonrandomized trials and case series. Technical complications comprised stent migration (4·0 per cent), graft limb thrombosis (3·9 per cent), endoleak (type I, 6·8 per cent; type II, 10·3 per cent; type III, 4·2 per cent) and access artery injury (4·8 per cent).

Discussion

EVAR is technically effective and safe, with lower short-term morbidity and mortality rates than open surgery. However, there is a need for extended follow-up as the long-term success of EVAR in preventing aneurysm-related deaths is not yet known.

Totally laparoscopic explantation of migrated stent graft after endovascular aneurysm repair: A report of two cases

This report describes the removal of two migrated stent grafts and the repair of abdominal aortic aneurysms by laparoscopic technique. In these two cases, endovascular treatment was not indicated because of device migration into the aneurysm and the presence of thrombus within the endografts. Operative times were 245 and 230 minutes, with aortic clamp times of 95 and 66 minutes. The patients were extubated immediately after the procedure, resumed a normal diet on postoperative day 2, and were discharged home on postoperative days 5 and 6. We believe these are the first reported cases of laparoscopic explantation of migrated aortic stent grafts in the literature.

Delayed Complications Following EVAR

More than a decade after the first clinical attempts, two large randomized studies have proven that endovascular aortic aneurysm repair (EVAR) provides immediate advantages over open repair. In the long run, however, a relatively high number of reinterventions is necessary to improve the long-term efficacy of EVAR, which may outweigh the early benefits. Since EVAR is gaining popularity in the medical community and in patients with abdominal aortic aneurysm (AAA), it is expected that a growing number of patients will present with delayed complications requiring some kind of reinterventions. For the patient's safety, vascular surgeons and interventional radiologists involved in EVAR must be well aware of these complications and the ways to overcome them. We began our endovascular program for AAA in 1994 and currently follow 485 patients with a variety of manufactured grafts. In this article we describe the delayed complications observed with EVAR, their mechanisms, favoring factors, and ways to treat them.