Most Patients with Abdominal Aortic Aneurysm Are Not Suitable for Endovascular Repair Using Currently Approved Bifurcated Stent-Grafts

The Correlation Of Aortic Neck Length To Late Outcomes Following EVAR with the Ovation Stent Graft

BACKGROUND

Endovascular aneurysm repair (EVAR) performed outside manufacturers' instructions for use (IFU) due to short aortic neck for the treatment of abdominal aortic aneurysm (AAA) is associated with unfavorable outcomes. Newer endografts now have an indication for shorter neck aneurysms that previous endografts do not, but this cohort has yet to be evaluated individually. The aim of this study is to evaluate 5-year outcomes after EVAR in patients with short aortic necks (<10mm) using the Ovation stent graft.

METHODS

The study comprised 238 patients who underwent EVAR as part of the prospective international multicenter Ovation stent graft trials. The main inclusion criteria were AAA diameter ≥ 5cm, proximal parallel neck length ≥7mm, neck angulation ≤60° and bilateral iliac fixation length ≥10 mm. A clinical events committee adjudicated adverse events through 1 year, an independent imaging core laboratory analyzed imaging through 5 years and a data safety and monitoring board provided study oversight. Patients were divided into short neck (<10mm) and standard neck (≥10mm) groups. Endpoints included long-term survival, freedom from aneurysm-related mortality (ARM), freedom from type Ia Endoleak and freedom from reintervention.

RESULTS

Patients were predominantly male (81%) with a mean age of 73±8 years. Median follow-up time was 58 months (IQR 36-60). Out of 238 patients, 41 (17.2%) had a proximal neck length <10mm and would be considered outside the IFU with other stent grafts. Baseline characteristics were relatively similar between the two groups. The 5-year overall survival estimates were 77.8% for the standard neck group compared to 59.5% for the short neck group (P= .03) (Figure1). There were no differences in the 5-year freedom from ARM (99.2% vs. 100%, P= .7), freedom from type Ia Endoleak (96.3% vs. 96.3%, P= .8) and freedom from reintervention (77.9% vs. 79.7%, P= .7) between the standard and short neck groups, respectively. After adjusting for age and other potential confounders, short proximal neck was associated with a 2-fold increase in 5-year all-cause mortality [aHR(95%CI): 2(1.02-3.8), P= .04].

CONCLUSION

The Ovation endograft performed well in short AAA neck with no difference in 5-year type Ia Endoleak, reintervention and ARM rates. However, short proximal neck was independently associated with a two-fold increase in the risk of all-cause mortality at five years. These findings confirm the prior literature on the association of hostile neck anatomy with late mortality following EVAR.

Endovascular aortic repair in patients with challenging anatomies: the EXTREME study

AIMS

The aim of this study was to report the 30-day technical and clinical success with endovascular repair using the ultra-low-profile Ovation stent graft in patients judged to be outside the instructions for use (IFU) for conventional endografts, while amenable to treatment within the IFU for Ovation.

METHODS AND RESULTS

One hundred and twenty-two patients (78.65±7.67 years; 111 male) were enrolled. Patients were evaluated as being outside the IFU for standard endografts because of the absence of a suitable proximal aortic neck in 109 cases (89.3%), of inadequate access vessels in 13 (10.7%), or both in 111 (90.9%). Mean aneurysm (abdominal aortic aneurysm [AAA]) diameter was 52.96±10.1 mm; mean aortic neck length was 7.75±6.05 mm. Technical success (98.4%) was achieved in all but two patients due to a type Ia endoleak. At completion angiography, 15 (12.3%) patients presented a type II endoleak. All patients underwent 30-day follow-up. Primary clinical success at one month was 96.8%, assisted clinical success 98.4%. There were no type I endoleaks, while 12 (9.8%) type II endoleaks were still evident, in the absence of sac expansions. Two patients (1.6%) presented an asymptomatic limb occlusion.

CONCLUSIONS

Our experience suggests that, in a selected population of patients with challenging anatomy outside the IFU for conventional endografts, endovascular aneurysm repair (EVAR) using the Ovation stent graft can be performed safely with satisfactory immediate outcomes.

Suitability of the Aortic Neck Anatomy for Endovascular Aneurysm Repair in Korean Patients with Abdominal Aortic Aneurysm

Purpose

To evaluate the aortic neck anatomy in Korean patients with abdominal aortic aneurysms (AAAs).

Materials and Methods

We examined computed tomography scans of 343 patients with AAAs (≥5.5 cm for men or ≥5 cm for women) between 2009 and 2018. Eligibility of neck anatomy for endovascular aneurysm repair (EVAR) was assessed with the standard instructions for use (IFU) (length ≥15 mm, suprarenal angulation (SRA) ≤45°, infrarenal angulation (IRA) ≤60°, and diameter 18-32 mm) and the extended IFU (length ≥10 mm, SRA ≤60°, IRA ≤75°, and diameter 17-32 mm).

Results

There were 71 women (20.7%), and 61 patients (17.8%) with rupture. Women had smaller neck diameters (21.3 vs. 23.4 mm, P<0.001 for proximal neck; 22.2 vs. 24.5 mm, P<0.001 for distal neck), and higher angulations (51.5° vs. 37.8°, P<0.001 for SRA; 77.7° vs. 57.0°, P<0.001 for IRA) than men. However, the neck length was not significantly different. Patients with ruptured AAAs had shorter neck lengths (21.0 vs. 26.8 mm, P=0.005) than those with intact AAAs. However, the neck diameters and angulations were not significantly different. EVAR eligibility for standard and extended IFUs was found in 37.5% and 55.1% of men, and 11.3% and 25.4% of women (P<0.001 for both IFUs); neck anatomy was eligible in 34.0% of intact AAAs and 23.0% of ruptured AAAs (P=0.098).

Conclusion

A significant proportion of the Korean patients did not meet the IFU for EVAR, mainly due to the angulated neck. Women, and patients with ruptured AAAs, were less likely to meet the IFU criteria.

Initial Clinical Experience Using the Low-Profile Altura Endograft System With Double D-Shaped Proximal Stents for Endovascular Aneurysm Repair

Purpose: To report the initial clinical results of endovascular aneurysm repair (EVAR) using the low-profile (14-F) Altura Endograft System, which features a double “D-shaped” stent design with suprarenal fixation and modular iliac components that are deployed from distal to proximal. Methods: From 2011 to 2015, 90 patients (mean age 72.8±8.3 years; 79 men) with abdominal aortic aneurysm (AAA; mean diameter 53.8±5.7 mm) were treated at 10 clinical sites in 2 prospective, controlled clinical studies using the Altura endograft. Outcomes evaluated included mortality, major adverse events (MAEs: all-cause death, stroke, paraplegia, myocardial infarction, respiratory failure, bowel ischemia, and blood loss ≥1000 mL), and clinical success (freedom from procedure-related death, type I/III endoleak, migration, thrombosis, and reintervention). Results: Endografts were successfully implanted in 89 (99%) patients; the single failure was due to delivery system malfunction before insertion in the early-generation device. One (1%) patient died and 4 patients underwent reinterventions (1 type I endoleak, 2 iliac limb stenoses, and 1 endograft occlusion) within the first 30 days. During a median follow-up of 12.5 months (range 11.5–50.9), there were no aneurysm ruptures, surgical conversions, or AAA-related deaths. The cumulative MAE rates were 3% (3/89) at 6 months and 7% (6/89) at 1 year. Two patients underwent coil embolization of type II endoleaks at 6.5 months and 2.2 years, respectively. Clinical success was 94% (84/89) at 30 days, 98% (85/87) at 6 months, and 99% (82/83) at 1 year. Conclusion: Early results suggest that properly selected AAA patients can be safely treated using the Altura Endograft System with favorable midterm outcome. Thus, further clinical investigation is warranted to evaluate the role of this device in the treatment of AAA.

The Relationship between Temporal Changes in Proximal Neck Angulation and Stent-Graft Migration after Endovascular Abdominal Aortic Aneurysm Repair

BACKGROUND

In recent years, endovascular abdominal aortic aneurysm repair (EVAR) for treating abdominal aortic aneurysms (AAA) has become quite prevalent in Japan. Though little information is available about temporal changes in proximal neck angulation due to the difficulties encountered in measuring the angle. Therefore, we examined temporal changes in proximal neck angulation and its relationship to stent-graft migration after EVAR.

METHODS

Between June 2007 and March 2010, 159 patients underwent EVAR for treatment of fusiform AAAs at our hospital. This study focuses on the 80 patients among this group whose treatment sites and subsequent stent grafts were examined by contrast computed tomographic angiography before surgery, directly after surgery (within 4 days), as well as 1 year and 2 years thereafter. We created curved planar reconstruction (CPR) images and measured the length of migration and neck angle using our method.

RESULTS

At 2 years after EVAR, the average length of proximal landing zone was 21.4 ± 9.2 mm. The average length of stent migration after 2 years was 1.41 ± 2.68 mm. The average neck angle was 33.9° preoperatively and 29.9° directly after surgery yielding a significant difference. However, 1 and 2 years after surgery the average neck angle was 28.2° and 28.4°, respectively. The number of patients experiencing a change >6° in the angle of the proximal neck between the preoperative condition and that directly after surgery was 16 (34.8%) with the use of Zenith stent grafts (n = 46) and 14 (41.2%) with the use of Excluder stent grafts (n = 34). There was no correlation between the proximal neck angle and migration of the proximal stent graft. In addition, there was no correlation between the changes in proximal neck angle and the secondary intervention rate and the occurrence of endoleak.

CONCLUSIONS

There was a significant change in the neck angle between the preoperative condition and the immediate postoperative condition. However, there was no clear relationship found between the angle of the neck and the proximal stent-graft migration. Postoperative changes in the proximal neck angle just after EVAR and subsequent temporal changes during a 2-year follow-up period do not appear to predict stent-graft migration, secondary intervention rates, or the occurrence of endoleak.

Endovascular aneurysm repair with the Ovation TriVascular Stent Graft System utilizing a predominantly percutaneous approach under local anaesthesia

OBJECTIVE

To present our experience with the Ovation Abdominal Stent Graft System (TriVascular Inc., Santa Rosa, CA) during endovascular aneurysm repair (EVAR) and compare results according to the type of anaesthesia.

METHODS

We conducted a single-centre retrospective study including patients who underwent EVAR using the Ovation endograft between May 2011 and July 2014. Outcome was evaluated regarding pre-, peri- and immediate postoperative and follow-up measures. Overall results are reported, while additional analysis was performed to compare the outcome between groups of patients undertaking either local or regional/general anaesthesia (LA vs RGA).

RESULTS

66 patients were included. Median follow-up was 13 months (range, 1-39 months). Median age was 72 years and median abdominal aortic aneurysm diameter was 58 mm (range, 54-100 mm). Technical success was 63 (95%), while there were 2 (3%) conversions to open surgery. A total percutaneous approach was used in 50/66 (76%) cases. Overall, 9/66 (14%) subjects suffered from any kind of morbidity. Median hospitalization was 3 days (range, 1-16 days). Immediate and midterm mortality rate was 0%. No endoleak Type I, III, IV or stent migration was observed. There were 8 (13%) Type II endoleaks. Overall, additional endovascular procedures were required in 6 (9%), while surgery was performed in 4 (6%) patients. 44 (67%) patients underwent LA and 22 (23%) RGA. Differences between groups were significant for procedural time (85 vs 107 min; p < 0.001), percutaneous access (91% vs 45%; p < 0.001) and systematic complications (2.3% vs 14%; p = 0.05).

CONCLUSION

EVAR with the use of the Ovation endograft shows promising short-term and midterm results regarding safety and effectiveness. Completion of the procedures under LA using a total percutaneous approach seems advantageous and may be used in routine practice.

ADVANCES IN KNOWLEDGE

The Ovation Abdominal Stent Graft System is an ultra-low profile stent graft system that allows percutaneous deployment for EVAR and offers excellent overall efficacy and safety. Totally percutaneous EVAR under LA seems advantageous and may be used as a routine with this specific endograft.

Mini-invasive aortic surgery: personal experience

OBJECTIVE

In this study, we retrospectively evaluated our experience in minilaparotomy (MINI) and compared the results with conventional open repair (OPEN).

METHODS

From January 2005 to December 2012, we surgically treated 234 consecutive patients with elective infrarenal abdominal aortic aneurysms, 195 men and 39 women, with a mean age of 74 years. Inclusion criteria for MINI were not ruptured abdominal aortic aneurysm, increased surgical risk, anatomical limits for endovascular repair, no previous surgical invasion of the abdominal cavity, and no requirement for concomitant abdominal surgical invasion. Surgical treatment was OPEN in 113 patients (48.3%) and MINI through an 8- to 14-cm incision in 121 patients (51.7%). Epidural anesthesia has been added in 26.5% and in 19.3% of the MINI and OPEN patients, respectively. Mortality, complications, aortic clamping time, operative time, need for postoperative morphine therapy, time to solid diet, and length of hospital stay were registered.

RESULTS

The MINI has been performed in all patients selected, with 72 aortoaortic grafts and 49 aortobisiliac grafts. Early mortality was 1.6% versus 3.5% (P > 0.5); 1-, 3-, and 5-year mortality were 7% versus 9%, 19% versus 22%, and 29% versus 34% (P > 0.5); complications were 12.2% versus 26.6% (P > 0.05); mean (SD) clamping time was 48 (12) versus 44 (14) minutes (P > 0.5); mean (SD) operative time was 218.72 (41.95) versus 191.44 (21.73) minutes (P > 0.025); mean (SD) estimated intraoperative blood loss was 425.64 (85.95) versus 385.30 (72.41) mL (P > 0.1); mean (SD) morphine consumption in the group given epidural and the group not given epidural was 0 (2) and 2 (2) mg intravenously (IV) versus 2 (4) (P < 0.5) and 4 (3) mg IV (P > 0.1); mean (SD) ambulation was 2.1 (0.6) versus 4.1 (2.7) (P < 0.5); mean (SD) time to solid diet was 2.1 (0.4) versus 3.5 (1.6) (P < 0.5); and mean (SD) length of hospital stay was 4.9 (1.64) versus 7.35 (1.95) days (P > 0.05), in the MINI and OPEN groups, respectively. Postoperative hernia at 3 years was 18% versus 23% in the MINI and OPEN groups (P < 0.5), respectively.

CONCLUSIONS

The MINI gives the patients a significantly shorter period of recovery with the quality and safety of the OPEN. This experience suggested extending the indication to all surgical candidates without local limitations.

Abdominal Aortic Aneurysm neck morphology: Proposed classification system

BACKGROUND

While aneurysm neck length, angulation and width have all been previously assessed in endovascular abdominal aortic aneurysm repair (EVAR), aneurysm neck shape has not been considered.

AIMS

To analyse the influence of aneurysm neck morphology on outcome following EVAR.

METHODS

Aneurysm neck morphology in 70 patients undergoing EVAR from April 2001 to May 2004 was determined using pre-operative CT scans and graft plans. Necks were classified as flared, parallel, irregular, conical, barrel or hourglass. End-points were death,Type I endoleak and graft migration.

RESULTS

Forty-six per cent of necks were flared, 34% parallel, 9% irregular, 6% conical, 3% barrel and 3% hourglass. Mean follow-up was 20.2 months (range 4-35). There was one Type I endoleak and one graft migration. There were no aneurysm related deaths.

CONCLUSIONS

Assessment of aneurysm neck morphology should be part of the routine preoperative workup for EVAR. A classification system of AAA necks is suggested to facilitate this.

Anatomic suitability for endovascular repair of abdominal aortic aneurysms and possible benefits of low profile delivery systems

The aim of the study was to evaluate the anatomic suitability for endovascular abdominal aneurysm repair (EVAR) according to instructions for use (IFUs) of three commercially available bifurcated stent graft devices and explore the possible benefits of low-profile delivery systems. Computed tomography scans of 241 patients with abdominal aortic aneurysm (AAA) were evaluated for suitability of Zenith Flex®, Gore Excluder® and Endurant® bifurcated stent graft systems according to their IFUs. The most common exclusion criteria and possible benefits of smaller diameter delivery systems were analyzed. When choosing the most suitable graft model for each patient, the overall suitability was 49.4%. By brand, the suitability was 28.6% for Zenith®, 25.7% for Gore Excluder® and 48.1% for Endurant®. By step wise accepting iliac diameters of ≥6 mm, ≥5 mm and ≥4 mm the overall suitability increased to 56.7, 58.9 and 60.2%, respectively ( P < 0.001). Diameters below 4 mm had no additional effect on suitability as combinations of other anatomical features, with or without narrow iliacs, accounted for the remaining excluding factors. In conclusion, Less than half of patients with AAAs are suitable for EVAR according to current IFUs. Low-profile delivery systems may allow for endovascular treatment in up to 60% of patients.

Women with abdominal aortic aneurysms have more extensive aortic neck pathology

BACKGROUND

The proportion of women with abdominal aortic aneurysm (AAA) treated with endovascular aortic repair (EVAR) is lower than for open repair (OR). Unfavorable morphologic features for EVAR in women with AAA may explain this disproportion. The objective of this study was to identify morphologic features in AAA patients undergoing elective repair with special emphasis on gender differences.

METHODS

Patients undergoing elective repair from January 1, 2006 to December 31, 2008 at our university's vascular unit were included in this study. Computed tomography (CT) angiograms were analyzed. Morphologic features considered unfavorable for EVAR rather than open repair (OR) included: infrarenal aortic neck <15 mm; angulation >60°; circumferential neck thrombus; neck width >32 mm; iliac arteries <7.5 mm; or presence of bi-iliac aneurysms. Complex aortic neck was defined as a neck length of <15 mm and one or more of the other aortic neck exclusion criteria.

RESULTS

One hundred seventy-two patients, including 140 men and 32 women, were treated during the study period, which included 99 with OR (21 women, 78 men) and 73 with EVAR (11 women, 62 men). Morphologic unsuitability for EVAR was 44% (75 of 172) and was not statistically different between women and men [47% (15 of 32) vs. 43% (60 of 140), P = 0.70]. Aortic neck pathology was the dominating feature for unsuitability for EVAR (69 of 75, 92%), and 85 of 172 patients had an unsuitable aortic neck. This rate was not different between women and men [19 of 32 (59%) vs. 66 of 140 (47%), P = 0.24]. Iliac unsuitability rates were 11% (19 of 172) and were not different between women and men [4 of 32 (12%) vs. 15 of 140 (11%), P = 0.76]. In patients unsuitable for EVAR, the proximal aortic necks showed more extensive aortic neck pathology in women than in men [8 of 15 (53%) vs. 13 of 60 (22%), P = 0.02]. More men had only short neck pathology [22 of 60 (37%) vs. 1 of 15 (7%), P = 0.03].

CONCLUSIONS

Aortic neck pathology is the dominating cause of EVAR exclusion in both genders. A higher proportion of women have more pathologic neck anatomy. Future development of EVAR devices should focus on the complexity of the aortic neck, which will benefit all AAA patients, but especially women.

Indications for fenestrated endovascular aneurysm repair

Background

Endovascular technology has advanced rapidly in the development of fenestrated endovascular aneurysm repair (FEVAR). Current evidence for endovascular aneurysm repair is limited to infra-renal aortic aneurysms. With increased costs and complexity of FEVAR, its current role is unclear. A national multicentre, cross-disciplinary consensus model was developed to propose indications for FEVAR.

Methods

All UK FEVAR centres and a wide selection of high-volume aneurysm treatment centres were invited to participate. The RAND appropriateness methodology was used. Five key steps were undertaken: meta-analysis of current literature; survey of current UK practice; nominal group establishment and definition of key clinical attributes; round 1—online survey of case vignettes; and round 2—nominal group consensus meeting.

Results

More than 90 per cent of UK FEVAR centres participated. Literature review showed heterogeneous case series with no clear indications for use of FEVAR. Survey of current practice showed wide variations in aneurysm management. Consensus agreement on the role of FEVAR was achieved in 68·8 per cent of cases. Consensus for FEVAR was agreed in areas of moderate risk from open repair and need for suprarenal clamping, but it was less likely to be indicated in patients aged 85 years or more with 5·5–6-cm aneurysms, or short-necked infrarenal aortic aneurysms.

Conclusion

These data record areas of agreement and define the grey area of equipoise. Consequently, guidelines and recommendations can be developed on the indications for FEVAR to inform clinicians, commissioners and health economists.

Two cases of endovascular abdominal aortic aneurysm repair with iliac aneurysm using a zenith iliac bifurcation graft

We report on treatment of an abdominal aortic aneurysm with common iliac artery aneurysm using an iliac branch device. We performed 2 cases because of a large common iliac artery aneurysm or a complication of an internal iliac artery aneurysm. Both cases had a good postoperative course and progressed without embolizing the iliac branch device during follow-up period. Though there is a drawback, it is not covered by the national insurance program in Japan and cannot be used in all applicable cases. However, use of a unilateral or bilateral iliac branch device allows us to maintain the bloodstream of the internal iliac artery, thus suggesting it to be effective in such cases.

Clinical practice change requires more than comparative effectiveness evidence: abdominal aortic aneurysm management in the USA

Adoption of healthcare innovations frequently outpaces the evidence of effectiveness. Endovascular repair (EVAR) for abdominal aortic aneurysms in the USA demonstrates how comparative effectiveness research without evidence-based reimbursement changes may fail to influence clinical practice. Randomized controlled trials for small abdominal aortic aneurysms demonstrate no lasting benefits of EVAR or open surgical repair (OSR) compared with surveillance, and for large abdominal aortic aneurysms demonstrate no lasting survival benefit of EVAR over OSR, and do show poorer durability and higher costs for EVAR. Nonetheless, >50% of elective abdominal aortic aneurysm repairs in the USA use EVAR. Factors that may be driving the high use of EVAR include patient preference, surgeons’ desire to appear ‘up-to-date’ in the procedures they offer, higher hourly surgeon reimbursement for EVAR than OSR, and the expansion of physician specialties able to perform abdominal aortic aneurysm repair from only vascular surgeons with OSR, to vascular surgeons and interventional radiologists/cardiologists with EVAR. By comparison, in Canada, where government health insurance restricts EVAR coverage to high surgical risk patients, only approximately 25% of abdominal aortic aneurysm repairs are performed using EVAR. Country-specific cost studies and a prospective population-based study collecting detailed clinical data to identify patient subgroups that truly benefit from a particular management strategy are needed to inform policy regarding EVAR availability and reimbursement.

Fenestrated endovascular aneurysm repair

Background

Fenestrated endovascular aneurysm repair (FEVAR) is a technically challenging operation. The duration, blood loss, and risk of limb ischaemia, contrast-induced nephropathy and reperfusion injury are likely to be higher than after standard endovascular aneurysm repair (EVAR). Benefits of FEVAR over open repair may be less than those seen with standard infrarenal EVAR. This paper is a meta-analysis of observational studies of all published data for FEVAR, with the aim to highlight current issues around the evidence for the potential benefit of FEVAR.

Methods

A search was performed for studies describing FEVAR for juxtarenal abdominal aortic aneurysms. Small series of fewer than ten procedures and studies describing predominantly branched endografts or FEVAR for aortic dissection were excluded. Authors of included papers were contacted to eliminate patient duplication.

Results

Eleven studies were identified describing a total of 660 procedures. Definitions of aneurysm morphology were variable, and clear inclusion and exclusion criteria were not always documented. Double fenestrations were more common than triple or quadruple fenestrations. Target vessel perfusion rates ranged from 90·5 to 100 per cent. Eleven deaths occurred within 30 days, giving a 30-day proportional mortality rate of 2·0 per cent. Morbidity was poorly reported.

Conclusion

FEVAR for repair of suprarenal and juxtarenal aneurysms is a viable alternative to open repair. However, there is no level 1 evidence for FEVAR, and current evidence is weak with many unanswered questions.

Two-dimensional versus three-dimensional CT angiography in analysis of anatomical suitability for stentgraft repair of abdominal aortic aneurysms

BACKGROUND

The morphological analysis prior to endovascular abdominal aneurysm repair (EVAR) plays an important role in long-term outcomes. Post-imaging analysis of computed tomographic angiography (CTA) by three-dimensional reconstruction with central lumen line detection (CLL 3D-CTA) enables measurements to be made in orthogonal slices. This might be more precise than equal post-imaging analysis in axial slices by two-dimensional computed tomographic angiography (2D-CTA).

PURPOSE

To evaluate the intra- and interobserver variability of CLL 3D-CTA and 2D-CTA post-imaging analysis methods and the agreement between them in pre-EVAR suitability analysis of patients with abdominal aortic aneurysm (AAA).

MATERIAL AND METHODS

Anonymized CTA data-sets from 70 patients with AAA were analyzed retrospectively. Length measurements included proximal and distal aortic neck lengths and total distance from the lower renal artery to the higher iliac bifurcation. Width measurements included proximal and distal neck diameters, maximum AAA diameter and common iliac diameters just above the iliac bifurcations. The measurements were performed in random order by two vascular surgeons, twice per method with 1-month interval between readings. In the CLL 3D-CTA method we used semi-automated CLL detection by software and manual measurements on CTA slices perpendicular to CLL. The equal measurements in 2D-CTA were performed manually on axial CTA slices using a DICOM viewer workstation. The intra- and interobserver variability, as well as the agreement between the two methods were assessed by Bland-Altman test and bivariate correlation analysis.

RESULTS

The intraobserver variability was significantly higher in 2D-CTA measurements for both readers. The interobserver variability was significant in 2D-CTA measurements of proximal neck dimensions while the agreement in CLL 3D-CTA analysis between the two readers was excellent in all studied parameters. The agreement between the two suitability analysis techniques was poor for both readers, especially in measurements of proximal neck's dimensions and in total aortoiliac length (p = 0.001).

CONCLUSION

In pre-EVAR morphological evaluation of AAAs the CLL-3D CTA post-imaging analysis has better intra- and interobserver correlation than 2D-CTA and might represent a useful tool for the proper selection of endograft's type and size.

"The chimney graft"-a simple technique for endovascular repair of complex juxtarenal abdominal aortic aneurysms in no-option patients

Endovascular aneurysm repair (EVAR) has developed as a less invasive alternative to open surgery for patients with abdominal aortic aneurysms. However, patients with very short infrarenal necks require complex surgical open repair, which is associated with increased mortality and morbidity. The risk of complex open repair may be prohibitive in high-risk patients. Thus, modifying the technique of EVAR may be required in such patients to successfully exclude aneurysms. An alternative that can be used in these patients is the so-called "chimney graft" technique. We report two cases where the chimney graft technique was used with good immediate results.

The influence of aneurysm size on anatomic suitability for endovascular repair

OBJECTIVES

It has been proposed that the threshold for repair of abdominal aortic aneurysms (AAAs) suitable for endovascular repair (EVAR) be lowered. A critical step in this pathway is determining whether smaller AAAs are more likely to be anatomically suitable for EVAR; that is, whether suitability is lost as the AAA grows.

METHODS

Patients who underwent ultrasound (US) imaging for asymptomatic AAAs at the University of Rochester Medical Center between January 1, 2003, and January 31, 2007, were identified. All those who had an abdominal/pelvic computed tomography (CT) scan ≤ 3 months of the US imaging were identified. CT scans were reviewed using predefined criteria to assess anatomic suitability for conventional EVAR (ie, without consideration of debranching).

RESULTS

Of 3005 aortic US studies performed during this period, 221 had CT scans showing infrarenal aneurysms. Of these, 168 patients (76%) were candidates for EVAR and 52 (24%) were not, most commonly due to a short neck (40; 77% of excluded). Size measured by CT scanning (mean, 53 ± 11 mm) averaged 4 mm larger than by US imaging (mean, 49 ± 10 mm; r(2) = 0.66; P < .0001). Aneurysm size measured by CT scanning (P < .0001) or US imaging (P < .0001) correlated with anatomic suitability for EVAR. Mean sizes for those suitable were 52 ± 9 mm by CT and 48 ± 7 mm by US imaging, whereas mean sizes for those not suitable were 58 ± 10 mm by CT and 53 ± 8 mm by US imaging. Receiver operating characteristic curve analysis demonstrated that an US cutoff of 4.87 mm best predicted anatomic suitability (86.2% if smaller, 64.8% if larger), whereas a CT cutoff of 57.0 mm best predicted suitability (84.7% if smaller, 63.2% if larger).

CONCLUSIONS

Aneurysm size measured by CT averaged 4 mm larger than by US imaging. Larger aneurysms are less likely to be anatomically suitable for EVAR, but the rate of suitability does not appreciably decrease until the aneurysm measures 49 mm by US imaging or 57 mm by CT scanning. This implies that waiting until the aneurysm reaches currently accepted size criteria for repair does not result in "missing the window" for EVAR; in other words, just as many patients are anatomically suitable for EVAR at currently accepted size cutoffs than if earlier intervention had been done.

Thoracic Endograft for Abdominal Aortic Aneurysms, an Unusual Application for Severe Neck Angulation: Case Report and Literature Review

Our goal was to achieve complete proximal sealing in severe aortic neck angulation (SNA) during endovascular aneurysm repair (EVAR) of a patient with an abdominal aortic aneurysm (AAA) unfit for surgery. An 82-year-old patient with an infrarenal AAA of 9.8 cm with an SNA of 90° was admitted for acute coronary syndrome. Following coronary treatment, the patient was considered unfit for surgery and therefore was evaluated for EVAR. Aneurysm sac exclusion was obtained with the deployment of a Powerlink bifurcated graft (Endologix Inc, Irvine, CA) inside a Relay thoracic endograft (Bolton Medical, Florida) placed just below the most distal renal artery. At 6 months, computed tomographic angiography confirmed correct graft placement, complete aneurysm exclusion, and a reduction in the aneurysmal sac. In AAA patients with an SNA at high risk of EVAR failure, the adaptability of a thoracic endograft could be considered for proximal sealing.

Initial experience of branched endovascular graft for abdominal aortic aneurysm with complex anatomy of proximal neck: planning and technical considerations

The purpose of this report was to demonstrate initial Japanese cases of abdominal aortic aneurysm (AAA) with complex anatomy of proximal neck treated using a Zenith fenestrated endograft with branched endovascular technique and to describe the device's design and technical considerations. Planning and sizing of endografts were performed using high-resolution computed tomography on a three-dimensional workstation. Branched endograft technique combined with reinforced fenestrated device and balloon-expandable stent graft was used in two patients because of challenging morphology for the fenestrated device with a bare stent. Successful exclusion of the aneurysm sac was achieved in both patients with antegrade perfusion in incorporated visceral vessels. Endovascular repair using a fenestrated device with graft material incorporating the visceral arteries is feasible. The combination of the reinforced fenestration and the balloon-expandable stent graft can provide an adequate sealing effect for the compromised anatomy. Initial and midterm results are reported with further follow-up and patient accrual.

Internal iliac artery branch stent grafting for aortoiliac aneurysms using the Apollo branched device

The association of aortic and common iliac artery aneurysms requires a special strategy to achieve distal seal during the endovascular exclusion of abdominal aortic aneurysms. Coil embolization of the internal iliac artery before the placement of a bifurcated endograft limb into the external iliac artery is a usual option. Such procedures are usually well tolerated but may result in buttock claudication, postprocedural sexual dysfunction, and colonic ischemia. We report on an alternative repair to preserve internal iliac artery patency using the Apollo iliac branched device.

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.

Type II endoleaks: when is intervention indicated and what is the index of suspicion for types I or III?

One of the principal reasons for failure of endovascular aneurysm repair (EVAR) is the occurrence of endoleaks, which regardless of size or type can transmit systemic pressure to the aneurysm sac. There is little debate that type I endoleaks (poor proximal or distal sealing) are associated with continued risk of aneurysm rupture and require treatment. Similarly, with type III endoleak, there is agreement that the defect in the device needs to be addressed; however, what to do with type II endoleaks and their effect on long-term outcome are not so clear. Aneurysm sac change is a primary parameter for determining the presence of an endoleak and assessing its impact. While diameter measurement has been the most commonly used method for determining sac changes, volume measurement has now been proven superior for monitoring structural changes in the 3-dimensional sac. Determining the source of an endoleak and the direction of flow are necessary for proper classification; however, while computed tomographic angiography has high sensitivity and specificity for detecting endoleaks, it is limited in its ability to show the direction of flow. Contrast-enhanced duplex ultrasound, on the other hand, is better able to quantify flow and characterize endoleaks. Flow is evidence of pressure, and increasing intrasac pressure increases wall tension, thus inducing progressive aneurysm expansion until rupture. Hence, determining intrasac pressure is becoming a vital component of endoleak assessment. All endoleaks can create systemic pressure inside the aneurysm sac, and there are a variety of intrasac pressure transducers being evaluated to assess this effect. A clinical pathway for patients with suspected type II endoleaks is based on a combination of imaging and pressure measurements. Imaging alone requires at least two interval examinations to determine the trend, while pressure measurements give immediate reassurance or an indication to intervene. Although still under development, pressure measurement is destined for general use and will provide a scientific basis for the management of type II endoleaks.

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.

Limited feasibility in endovascular aneurysm repair using currently available graft in Korea

Despite the wide acceptance of endovascular aneurysmal repair in patients with abdominal aortic aneurysm (EVAR), stringent morphologic criteria recommended by manufacturers may preclude this treatment in patients with AAA. The purpose of this study was to investigate how many patients are feasible by Zenith and Excluder stent graft system, which are available in Korea. Eighty-two AAA patients (71 men, mean age 70 yr) who had been treated surgically or medically from January 2005 to December 2006 were included. Criteria for morphologic suitability (MS) were examined to focus on characteristics of aneurysm; proximal and distal landing zone; angulation and involvement of both iliac artery aneurysms. Twenty-eight patients (34.1%) were feasible in Zenith stent graft and 31 patients (37.8%) were feasible in Excluder. The patients who were excluded EVAR had an average of 1.61 exclusion criteria. The main reasons for exclusion were an unfavorable proximal neck (n=34, 41.5%) and problem of distal landing zone (n=25, 30.5%). There was no statistical significance among gender, age or aneurysm size in terms of MS. Only 32 patients (39%) who had AAA were estimated to be suitable for two currently approved grafts by strict criteria. However, even unfavorable AAA patients who have severe co-morbidities will be included in EVAR in the near future. Therefore, more efforts including fine skill and anatomical understanding will be needed to meet these challenging cases.

Large iliac arteries: a high-risk group for endovascular aortic aneurysm repair

PURPOSE

To examine if the presence of large iliac arteries is a potential risk factor for the development of a type Ib endoleak (iliac sealing zone) or need for iliac artery-related secondary intervention in patients undergoing endovascular abdominal aortic aneurysm repair.

METHODS

The medical notes and all preoperative and postoperative plain abdominal radiographs and computer tomographic scans were reviewed for a consecutive series of 100 patients (89 men; mean age 75 years, range 56-91) with large iliac arteries (mean 19.7 mm, range 16-22) who had Zenith endovascular stent-grafts inserted for management of aortoiliac aneurysmal disease from January 1999 until September 2002. Endpoints were all-cause mortality, aneurysm-related death, endoleak, secondary intervention, secondary interventions, and stent-graft migration.

RESULTS

Mean follow-up was 30.1+/-8.3 months; at the last follow-up, 30% of patients were dead, 3% were aneurysm-related. Seven (7%) patients developed a type Ib endoleak, with the remainder being type II (29%), type Ia (2%), type III (1%), and type V (endotension, 1%). Eight (27.5%) type II endoleaks persisted, with the remainder closing spontaneously with sac shrinkage. The iliac artery-related secondary intervention rate was 10%, and the overall secondary intervention rate was 16%.

CONCLUSION

Iliac arteries between 16 and 22 mm in diameter may be treated with a cuff to the iliac limb with an expectation of 90% efficacy. Surveillance is required, with a high index of suspicion for type 1b endoleaks. Early secondary iliac intervention with extension to the external iliac artery is recommended if there is an increase in sac size after 6 months.