Endoleak: predictive value for aneurysm growth at 3 years

Rupture of Excluded Popliteal Artery Aneurysm: Implications for Type II Endoleaks

The fate of popliteal artery aneurysms after ligation and bypass is believed to be relatively innocuous. The patient presented in this report, however, experienced spontaneous rupture of a popliteal aneurysm 11 years after ligation and bypass. Magnetic resonance angiography was used to establish the diagnosis of rupture, which was subsequently confirmed at surgery. Intraoperative arteriography demonstrated persistent collateral arterial perfusion of the excluded popliteal aneurysm sac. The collateral arterial flow originated from the superior and inferior lateral genicular arteries. The persistent arterial perfusion resulted in growth of the aneurysm from 4.2 to 7.0 cm over the 11-year period. The ruptured aneurysm was successfully treated by direct arterial exposure and suture ligation of the collateral vessels performed from within the aneurysm sac. The development of popliteal aneurysm expansion and rupture as a result of collateral arterial perfusion suggests that persistent collateral perfusion of abdominal aortic aneurysms after endovascular repair (type II endoleak) may lead to aneurysm rupture. Therefore, close observation and intervention for aneurysm expansion to prevent rupture of the excluded aneurysm are warranted.

The Roadside Technique for Type II Endoleak Embolization 4 Years after Endovascular Aortic Aneurysm Repair

Endoleaks are the most common cause of reintervention after endovascular aortic aneurysm repair (EVAR). Type II endoleaks have been implicated as a risk factor for expansion and rupture. Several techniques have been described to manage type II endoleaks, being transarterial catheterization the most commonly used. In some cases this technique can be difficult or impossible to achieve. We report the use of a technique that offers a direct access to the aneurysm sac and the possibility of catheterization of the involved vessels or the embolization of the communication between them, even 4 years after EVAR.

[Type III endoleaks at follow-up of covered descending thoracic aortic stent-grafts: report of 3 patients]

PURPOSE

To describe the imaging work-up and management of type III endoleaks detected after covered stent-graft treatment of descending thoracic aortic aneurysms.

PATIENTS AND METHODS

Retrospective study of circumstances surrounding the diagnosis, management and outcome type III endoleaks occuring in 3 of 18 patients following covered stent-graft treatment of descending thoracic aortic aneurysms between April 1998 and July 2005. The endoleaks were detected at a mean follow-up of 22 months (19-24 months) after stent-graft placement.

RESULTS

The type III endoleaks were detected on scheduled follow-up CT examinations in asymptomatic patients. Endovascular management was proposed at a mean interval time of 4.4 months (1 week - 11 months) after diagnosis of the endoleak, and was successful in all 3 cases. One patient died 1 month after endovascular repeai of the leak, 1 patient required surgical management at 14 months for new recurrence, and 1 patient had a favorable outcome at 2 months.

CONCLUSION

Follow-up of patients after covered stent-graft treatment of descending thoracic aortic aneurysms is required. Prompt endovascular repair of delayed complications may be possible, but surgical management may become necessary.

Endovascular treatment of atherosclerotic and other thoracic aortic aneurysms

The incidence of thoracic aortic aneurysms (TAAs) is increasing with the present rate of occurrence at 10.9 cases per 100,000 people per year. The estimated 5-year risk of rupture of a TAA with a diameter between 4 and 5.9 cm is 16%, but it rises to 31% for aneurysms ≥ 6 cm. Despite increasing awareness of the importance of early diagnosis and treatment options, there are no clear guidelines available at the time of writing. Nor is there any clear evidence for specific pharmacological treatment able to resolve or delay the disease progression. Endovascular treatment (EVT), proposed as an alternative to surgery, has been considered a therapeutic innovation, especially because it is minimally invasive, which allows treatment even in high surgical risk patients. Vascular imaging is crucial for patient selection, endoprosthesis choice, and planning of the treatment because not all aneurysms are suitable. Early and midterm results are encouraging, but long-term results are necessary to definitively assess reliability of stent-graft materials and improvement in patient survival. In the choice between surgical or endovascular repair of TAAs, many factors must be considered, including the clinical situation, comorbidities, anatomy, choice of equipment, and last, but not less important, experience of the clinical team.

An 8-year experience with type II endoleaks: Natural history suggests selective intervention is a safe approach

OBJECTIVE

The treatment of type II endoleaks remains controversial because little is known about their long-term natural history and impact on changes in aneurysm morphology. This study reviews type II endoleaks occurring in patients after endovascular abdominal aortic aneurysm repair (EVAR) at a single-institution over an 8-year period.

METHODS

All patients undergoing EVAR who had type II endoleaks documented on follow-up imaging studies at our institution between January 1997 and March 2005 were reviewed. Data regarding patient demographics in addition to aneurysm size, device type, operative complications, and secondary interventions were reviewed. Outcomes evaluated included the rate of spontaneous sealing, freedom from secondary intervention, and aneurysm enlargement, rupture, or conversion.

RESULTS

Type II endoleaks were present in 154 of 965 patients (16.0%) undergoing EVAR. Mean follow-up time was 22.0 months (range, 1 to 72 months). Fifty-five patients (35.7%) with type II endoleaks sealed spontaneously in a mean time of 14.5 months. According to Kaplan-Meier analysis, approximately 75% of type II endoleaks sealed spontaneously within a 5-year period. Nineteen patients (12.3%) with type II endoleaks were treated at a mean time of 19.9 months at the operating surgeon's discretion, including 13 with sac enlargement >5 mm. Kaplan-Meier analysis estimated that approximately 65% of the patients remained free of intervention after a period of 4 years. Thirteen patients (8.4%) experienced aneurysm sac enlargement >5 mm. Kaplan-Meier analysis estimated that approximately 80% of patients with type II endoleaks remained free of sac enlargement >5 mm over a 4-year period. No patients with type II endoleaks experienced rupture or required conversion to open repair during their follow-up. Cox regression analysis showed that cancer, coronary artery disease, and chronic obstructive pulmonary disease were associated with earlier spontaneous closure of the type II endoleaks (P < .05).

CONCLUSIONS

We observed that type II endoleaks have a relatively benign course, and in the absence of sac expansion, can be followed for a prolonged course of time without the need for intervention. The rate of spontaneous seal continues to increase with time and, therefore, close follow-up of patients with type II endoleaks who show no signs of aneurysm expansion is a safe approach. For patients in whom the exact etiology of their endoleak is in question, dynamic imaging should be used to exclude the presence of a type I endoleak.

Results of endovascular repair of the thoracic aorta with the Talent Thoracic stent graft: The Talent Thoracic Retrospective Registry

BACKGROUND

Endovascular treatment of thoracic aortic diseases demonstrated low perioperative morbidity and mortality when compared with conventional open repair. Long-term effectiveness of this minimally invasive technique remains to be proven. The Talent Thoracic Retrospective Registry was designed to evaluate the impact of this therapy on patients treated in 7 major European referral centers over an 8-year period.

METHODS

Data from 457 consecutive patients (113 emergency and 344 elective cases) who underwent endovascular thoracic aortic repair with the Medtronic Talent Thoracic stent graft (Medtronic/AVE, Santa Rosa, Calif) were collected. Follow-up analysis (24 +/- 19.4 months, range 1-85.1 months) was based on clinical and imaging findings, including all adverse events. To ensure consistency of data interpretation and event reporting, one physician reviewed all adverse events and deaths for the whole cohort of patients. In the case of discrepancies, the treating physicians were queried.

FINDINGS

Among 422 patients who survived the interventional procedure (in-hospital mortality 5%, 23 patients), mortality during follow-up was 8.5% (36 patients), and in 11 of them the death was related to the aortic disease. Persistent endoleak was reported at imaging follow-up in 64 cases: 44 were primary (9.6%) and 21 occurred during follow-up (4.9%). Seven patients with persistent endoleak had aortic rupture during follow-up, at a variable time from 40 days to 35 months, and all subsequently died. A minor incidence of migration of the stent graft (7 cases), graft fabric alteration (2 cases), and modular disconnection (3 cases) was observed at imaging. Kaplan-Meier overall survival estimate at 1 year was 90.97%, at 3 years was 85.36%, and at 5 years was 77.49%. At the same intervals, freedom from a second procedure (either open conversion or endovascular) was 92.45%, 81.3%, and 70.0%, respectively.

CONCLUSION

Endovascular treatment for thoracic aortic disease with the Talent stent graft is associated with low early morbidity and mortality rates also for patients who are at high risk and treated on an emergency basis. Follow-up data indicate a substantial durability of the procedure with a high freedom from related death and secondary interventions.

Factors predictive of early or late aneurysm sac size change following endovascular repair

OBJECTIVE

The purpose of this study was to determine the relationship between aneurysm sac size change at 1, 6, 12, and 24 months and a set of 10 independent "predictive" variables by using a general linear model analysis.

METHODS

In a multicenter trial, 351 patients received the Zenith tri-modular bifurcated endograft. The predictive variables used for this analysis were endoleak by type, age, gender, smoking status, and the preprocedure variables of maximum aneurysm major diameter, minor neck diameter, proximal neck length, neck plaque/thrombus, and neck shape; and patent inferior mesenteric artery at predischarge. The aneurysm change was calculated as the difference from the predischarge (< or = 7 days of implant) maximum aneurysm major diameter measurement to the maximum aneurysm major diameter measurement at follow-up examination periods of 1, 6, 12, and 24 months. The same 10 predictive variables were used to assess the absolute change in maximum aneurysm minor diameter and aneurysm area. Additionally, the percent change from predischarge was also assessed for the major diameter, minor diameter, and aneurysm area.

RESULTS

None of the independent variables were predictive of absolute sac size change or percent change at 1 month. At 6 months, the presence of an endoleak (P < .01) and preprocedure neck thrombus/plaque (P = .01) were significant predictors of absolute and relative aneurysm size change for all measurements (major diameter, minor diameter, and area) and were more likely to be associated with less sac shrinkage or to have sac growth. Additionally, preoperative maximum aneurysm major diameter was a significant predictor for absolute change in area (P < .01). Larger preprocedure aneurysm diameters were more likely to experience more shrinkage. The significant predictors of size change at 12 months included preprocedure maximum aneurysm major diameter, the presence of endoleak at 12 months, preoperative neck thrombus/plaque, and gender. At 24 months, significant predictors of aneurysm size change included preprocedure maximum aneurysm major diameter, endoleak at 24 months, and preprocedure neck thrombus/plaque. When the longitudinal model was used, the presence of an endoleak, thrombus/plaque within the proximal neck at preprocedure, and preprocedure maximum aneurysm major diameter were found to be significantly related to the size of the maximum aneurysm major diameter over time.

CONCLUSIONS

This study supports the concept that early and late sac size change following EVAR is influenced by identifiable independent predictive variables.

SPECTRAL DOPPLER CHARACTERIZATION OF ENDOLEAKS FOLLOWING ENDOLUMINAL ABDOMINAL AORTIC ANEURYSM REPAIR

BACKGROUND

Colour Doppler ultrasound of endoluminal abdominal aortic aneurysm repair is becoming an established imaging technique in identifying endoleak. Management and treatment of endoleak is determined in part by the exact nature of the endoleak, namely its type and whether it has single or multiple vessel inflow and outflow. To date, spectral Doppler waveform analysis has provided some information about the propensity for spontaneous seal of isolated type II endoleaks, rather than assisting in their classification.

METHODS

We present a collection of three case reports outlining the directionality/phasicity of the Doppler waveform profile associated with endoleaks whose type and subtype (uni- /or multi-conduital) were angiographically determined.

RESULTS

In all three cases uniconduital type II endoleak demonstrated a to-and-fro waveform on Doppler ultrasound imaging.

CONCLUSIONS

To-and-fro Doppler waveforms may be associated with uniconduital type II endoleaks. If upon investigation of further cases this is found to be the case, this waveform classification may facilitate determination of the subtype (uni- or multi-conduital) of endoleak, thus identifying those cases which may be more amenable to percutaneous repair.

Endovascular treatment of abdominal aortic aneurysms

BACKGROUND

Endovascular treatment of abdominal aortic aneurysms is a rapidly evolving technique that has gained broad acceptance in the treatment of patients with abdominal aortic aneurysms.

METHODS

A review of the English literature was done to determine the short- and long-term outcomes of endovascular repair of abdominal aortic aneurysms. Reports of complications such as endoleak, graft migration, graft limb occlusion, aneurysm rupture, and aneurysm enlargement were evaluated.

RESULTS

Short-term results of endovascular repair of abdominal aortic aneurysms are excellent. The necessity for open conversions is less than 5%. The cumulative risk of aneurysm rupture is approximately 1% per year. The coverall incidence of graft limb occlusion was 2.8% in the follow-up period. The cumulative risk for a secondary procedure was 12% at 1 year, 24% at 2 years, and 35% at 3 years. Moderate and severe neck angulation was associated with an increased incidence of adverse events in the follow-up period. Endografts have the potential to become infected and develop aortoduodenal fistula. The treatment of ruptured aneurysms with endovascular grafts has been successful and a technique that is increasingly used.

CONCLUSION

Endovascular treatment of abdominal aortic aneurysm is an effective technique with excellent short-term results. The long-term results remain to be determined. Ongoing surveillance is necessary to avoid late complications of aneurysm rupture.

Endovascular treatment of abdominal aortic aneurysm

BACKGROUND

Endovascular repair of abdominal aortic aneurysm has become widely used. Supporters claim high success rates, few complications and a dramatically reduced hospital stay. However, endoleak, endotension and reports of endoprosthesis rupture are causes of concern.

METHODS

A Medline search was undertaken to identify articles on endovascular repair of abdominal aortic aneurysm. Additional papers were identified by manual scanning of the references from key articles.

RESULTS AND CONCLUSION

Endoleak is a potentially serious complication of the endovascular technique and occurs in a significant proportion of patients. It is still not possible to judge whether the presence of an endoleak alone signifies failure of treatment, and the long-term durability of prosthetic covered stents is unknown. However, endovascular repair does appear to confer a degree of protection from rupture although patients must be advised of the need for life-long imaging surveillance and, perhaps, further intervention.

Variable sac behavior after endovascular repair of abdominal aortic aneurysm: analysis of core laboratory data

OBJECTIVES

The behavior of the aneurysm sac after endovascular grafting has been the subject of significant speculation. The importance of sac behavior is manifested by the correlation between aneurysm size or size change and risk for rupture, and potentially further extrapolated to define the need for secondary intervention. This study was undertaken to define graft-specific differences and the effect of endoleak on sac remodeling.

METHODS

Core laboratory data were obtained for three US Phase II clinical trials. Patients were included if they met anatomic inclusion criteria and underwent placement of the latest version of a bifurcated endovascular prosthesis. Unsupported Dacron (Ancure), supported Dacron (Zenith), and expanded polytetrafluoroethylene (Excluder) grafts were evaluated. Digitized images were electronically assessed for aneurysm size (area, maximum, minimum diameter) with National Institutes of Health Image software. Two blinded reviewers analyzed each radiographic study to ensure accurate image selection and establish the presence or absence of endoleak. A third reviewer adjudicated discrepancies. chi(2) analysis and mixed nonlinear modeling were used to analyze the results.

RESULTS

Of 1506 patients evaluated, 723 (227 Ancure, 343 Excluder, 153 Zenith) met inclusion criteria for the study. Mean follow-up was 23.2 months (Ancure, 31.3 months; Excluder, 19.6 months; Zenith, 19.3 months). The incidence of any endoleak was 39.1% (Ancure, 58.1%; Excluder, 34.7%; Zenith, 20.9%; P <.001). Type of prosthesis, presence or absence of endoleak, and baseline size were determinants of rate of aneurysm shrinkage. Reduction in sac size was greatest with the Zenith graft, followed by the Ancure and Excluder grafts. Presence of endoleak had a moderating effect on rate of sac shrinkage with the Zenith and Ancure grafts; however, sac size increased in the presence of endoleak with the Excluder graft. Finally, baseline size was positively correlated with rate of aneurysm shrinkage.

CONCLUSIONS

The behavior of the aneurysm sac depends on the type of prosthesis, presence or absence of endoleak, and baseline size of the sac. Differential sac behavior must be considered when determining the need for secondary interventions, timing follow-up studies, and assessing success or failure of endovascular repair.

Descending thoracic aortic diseases: stent-graft repair

PURPOSE

To evaluate endovascular treatment of descending thoracic aorta with commercially available self-expanding stent-grafts.

MATERIALS AND METHODS

Seventy patients with aortic dissection, intramural hemorrhage, degenerative and posttraumatic aneurysm, penetrating atherosclerotic ulcer, and pseudoaneurysm underwent endovascular treatment. Eleven patients had impending rupture and were treated on an emergency basis. Stent-grafts were customized or selected on the basis of spiral computed tomographic (CT) or magnetic resonance (MR) imaging measurements. Preprocedure diagnostic angiography was performed in patients with aortic dissection and in other selected patients. All procedures were performed in an operating room and monitored with digital subtraction angiography (DSA) and transesophageal echocardiography (TEE). Follow-up was at 1, 3, 6, and 12 months after treatment and yearly thereafter.

RESULTS

Stent positioning was technically successful in 68 cases. At DSA and TEE, complete aneurysm or false-lumen exclusion was achieved in 66 (97%) cases. No intraoperative mortality or complications occurred. In-hospital complications included transient monoparesis (one patient) and extension of dissection into ascending aorta (one patient) that was repaired surgically. Early endoleak was observed in five (7%) patients: In three (type 2), endoleak resolved spontaneously; in one (type 1), it was persistent; and in one (type 1), treatment was converted to surgery. At long term, one (1%) patient died of aortic rupture; another, of respiratory insufficiency. Five (7%) late endoleak (type 1, one caused by migration of the stent) cases were observed. In three (4%), endovascular treatment was successful; in two (3%), surgery was performed. In one patient with persistent postimplantation syndrome, treatment was converted to surgery after successful aneurysm sealing. Procedure failure (ie, aortic disease-related mortality or conversion to surgery) occurred in six (9%) patients.

CONCLUSION

Endovascular stent-graft repair is less invasive in patients with chronic and acute descending thoracic aortic aneurysm and dissection.

Does the type of endograft affect AAA volume change after endovascular aneurysm repair?

PURPOSE

To compare thrombus volume changes in a longitudinal study over 2 years after endovascular aneurysm repair using the Ancure and Excluder endografts.

METHODS

In 2 institutions, all consecutive patients treated with a bifurcated Ancure or Excluder endograft were included in this retrospective comparison of computed tomographic angiography (CTA) data recorded and stored to disk postoperatively and at the 12 (12M) and 24-month (24M) follow-up examinations. In one institution, among 45 Ancure endograft patients, 35 (group A) had the 3 requisite scans available. In the second institution, 23 (group B) of 36 patients with the Excluder endograft were eligible for analysis. The proportional volume change was calculated at 12M and 24M and compared to the postoperative CT data. More than 10% shrinkage was considered significant.

RESULTS

In both groups, the median absolute volume changed significantly. In group A, significant shrinkage was found in 66% (23/35) at 12M and 74% (26/35) at 24M; in group B, 46% (10/23) had significant shrinkage at 12M as well as at 24M (p=0.027 for the difference between groups A and B at 24M). Statistical analysis of the proportional volume change showed a significant difference between the Ancure and the Excluder devices at 12M (p=0.009) and 24M (p=0.001). Multivariate analysis found aneurysm size (p<0.012) and endograft type (p=0.026) to be independently predictive of the absolute volume change.

CONCLUSIONS

Sac volume shrinkage after endovascular aneurysm repair is less pronounced and less frequent with the Excluder endoprosthesis than with the Ancure endograft.

The endovascular repair of abdominal aortic aneurysm: an update analysis of structural failure modes of endovascular stent grafts

Over the last decade, more than 25,000 endovascular stent grafts have been used to treat aortic aneurysms. Although results have been promising thus far, problems with endoleaks, material failure, device migration, and aneurysm rupture continue to be reported. Improvements in device material and design have contributed to the rapid growth and utility of these devices; however, material failure still remains a concerning mode for potential procedure failure. A review of the authors'experience with material failure and a review of the literature was conducted to help understand and comprehend the magnitude of this problem and try to determine its clinical significance.

Fate of excluded popliteal artery aneurysms

OBJECTIVE

Popliteal artery aneurysms (PAA) are frequently treated with ligation and exclusion bypass grafting. It is assumed that these aneurysms will shrink and remain asymptomatic. This may not always be true. We sought to elucidate the fate of excluded PAA over time.

METHODS

Data for all PAAs treated with ligation and exclusion bypass grafting between 1986 and 1999 were retrospectively reviewed. Computed tomography (CT) scans and duplex ultrasound scans provided aneurysm patency data and maximal transverse diameter measurements of the popliteal artery during late postoperative follow-up. This information was compared with that from similar preoperative studies.

RESULTS

Forty-one patients (39 men, 2 women) underwent 57 ligation and exclusion bypass grafting procedures. Both preoperative and late postoperative (mean, 4.0 years; range, 0.43-13.5 years) CT scans or duplex ultrasound scans were available for review of 25 PAAs in 18 patients (ages 42-80 years; mean, 63 years). Preoperative PAA size ranged from 14 to 45 mm (mean, 28.7 mm). In late follow-up, 12 (48%) PAA had decreased in size (mean, 7.3 mm), 5 (20%) remained unchanged, and 8 (32%) increased in mean transverse diameter (mean, 5.9 mm). One large aneurysm increased by 50%. Contrast material enhancement was identified in the excluded sac in 11 aneurysms.

CONCLUSIONS

PAA treated with ligation and exclusion bypass grafting often expand and can become symptomatic. This may be analogous to type II endoleak or endotension noted after aortic endovascular repair. We recommend PAA excision or endoaneurysmorrhaphy when feasible.

Abdominal aortic aneurysm size regression after endovascular repair is endograft dependent

OBJECTIVE

This study was performed to determine whether abdominal aortic aneurysm (AAA) regression is different with various endografts after endovascular repair.

METHODS

A four-center retrospective review of size change after endovascular AAA repair was performed. Consecutive patients with at least 1-year follow-up and available imaging studies were included. Three hundred ninety patients received either the Ancure, AneuRx, Excluder, or Talent endograft. AAA size and endoleak status were recorded from computed tomography (CT) scans at the initial postoperative follow-up visit and at 1 and 2 years thereafter. AAA size was defined as the minor axis of the infrarenal aorta on the largest axial section on the two-dimensional CT scan. A change in AAA size of 0.5 cm or greater from baseline was considered clinically significant. The effect of initial size, endoleak, and type of endograft on AAA regression was analyzed.

RESULTS

Mean baseline size was significantly greater with Talent endografts and smaller with Excluder endografts. Clinically significant regression in AAA size occurred in nearly three fourths of patients with Ancure and Talent endografts at 2 years. Regression in AAA size was less frequent with the AneuRx (46%) and Excluder (44%) devices. Initial size, endoleak, and endograft type were significant predictors of regression at multivariate analysis at 1 year. However, by 2 years only endograft type was still an independent predictor of AAA shrinkage.

CONCLUSIONS

Long-term morphologic changes after endovascular aneurysm repair depend on endograft type.

Controversies in the management of type II "branch" endoleaks following endovascular abdominal aortic aneurysm repair

Successful endovascular aortic aneurysm repair (EVAR) is often defined as complete exclusion of blood flow within the aneurysm sac. Perigraft flow, also known as endoleak, is the most common complication following EVAR. Attachment site related endoleaks (type I) are generally considered to warrant some form of intervention due to the belief that they represent a risk for future rupture. Management of type II endoleaks, also known as branch or collateral endoleaks, is more controversial. Some advocate a policy of watchful-waiting whereas others treat all type II endoleaks as soon as they are discovered. The following review explores the controversies pertaining to the management, diagnosis and surveillance imaging, and treatment of type II endoleaks.

Mechanical failure of prosthetic human implants: a 10-year experience with aortic stent graft devices

OBJECTIVE

The first endovascular stent graft was implanted to treat an abdominal aortic aneurysm more than a decade ago. This technique has evolved dramatically with the growing understanding of metallurgic and fabric sciences and improved device designs. However the potential for stent graft material failure remains. This investigation describes the incidence of material failure, potential modes of device fatigue, and the clinical significance of these failures.

METHODS

Six hundred eighty-six endovascular stent grafts were used to treat patients with aortic aneurysms. Device fatigue in the form of stent, suture fracture, or graft wear was identified with an analysis of follow-up radiographs and explanted stent grafts. A review of patient clinical histories, spiral computed tomographic scan studies, scanning electron microscopy, and energy dispersion spectroscopy of explanted devices was conducted to evaluate the modes and consequences of failure.

RESULTS

Sixty patients were identified with device fatigue, 49 of whom had abdominal endovascular repairs and 11 of whom had thoracic repairs. Of the 60 patients with stent graft fatigue, 43 patients had metallic stent fractures, 14 had suture disruptions, and three had graft holes. These material failures occurred within seven distinct stent graft designs. The average time to the recognition of failure was 19 months, with a mean follow-up period of 8 months since the event was identified. Eleven patients died, and one was lost to follow-up 2 years after identification of a stent fracture. The remaining patients are presently being followed eoyj physical examination, plain film radiograph, and computed tomographic scans for clinical sequelae of device fatigue.

CONCLUSION

Endovascular stent graft fatigue has been recognized in numerous devices after aortic implantation. Fatigue may take the form of stent, graft, or suture failure, with certain modes unique to specific stent graft devices. The clinical significance of stent graft material failure remains uncertain.