Endovascular repair of aortic aneurysms: critical events and adjunctive procedures

Impact of iliac access in elective and non-elective endovascular repair of abdominal aortic aneurysm

Endovascular aortic repair (EVAR) is nowadays the establishment treatment for patients with abdominal aortic aneurysm (AAA) both in elective and urgent setting. Despite the large applicability and satisfactory results, the presence of hostile iliac anatomy affects both technical and clinical success. This narrative review aimed to report the impact of iliac access and related adjunctive procedures in patients undergoing EVAR in elective and non-elective setting. Hostile iliac access can be defined in presence of narrowed, tortuous, calcified, or occluded iliac arteries. These iliac characteristics can be graded by the anatomic severity grade score to quantitatively assess anatomic complexity before undergoing treatment. Literature shows that iliac hostility has an impact on device navigability, insertion and perioperative and postoperative results. Overall, it has been correlated to higher rate of access issues, representing up to 30% of the first published EVAR experience. Recent innovations with low-profile endografts have reduced large-bore sheaths related issues. However, iliac-related complications still represent an issue, and several adjunctive endovascular and surgical strategies are nowadays available to overcome these complications during EVAR. In urgent settings iliac hostility can significantly impact on particular time sensitive procedures. Moreover, in case of severe hostility patients might be written off for EVAR repair might be inapplicable, exposing to higher mortality/morbidity risk in this urgent/emergent setting. In conclusion, an accurate anatomical evaluation of iliac arteries during preoperative planning, materials availability, and skilled preparation to face iliac-related issues are crucial to address these challenges.

Quantifying the Functional Stiffness of Pullthrough Wires Used for Endovascular Aneurysm Repairs Using Comparative Tension Dynamometry

Objective

There are only few studies on the stiffness of guidewires used to deliver devices during endovascular procedures, particularly abdominal/thoracic endovascular aneurysm repair. In certain situations, tensioned pullthrough wires are also used, but no studies have examined their effective/functional stiffness. The objective of this study was to assess the radial stiffness characteristics of pullthrough wires compared with standard stiff wires.

Methods

Two types of stiff guidewires (Lunderquist Extra-Stiff and Amplatz Super Stiff; 0.035″ × 260 cm), were compared with a floppy guidewire (Radifocus Stiff M; 0.035″ × 260 cm) in two configurations: standard (non-tensioned) and pullthrough (tensioned). Radial stiffness was defined as the peak deformation force (PDF; newtons [N]) needed to deform the wires on an electromechanical dynamometer; data were logged on proprietary dynamometric software and peak load values assessed per wire. Three experimental runs were performed on three fresh sets of each wire per configuration. PDFs from straight configuration to midwire deformation at 15 mm were translated into Microsoft Excel for statistical analysis in Minitab 19 for Windows.

Results

Mean ± SD PDFs were 7.83 ± 0.23 N for the Lunderquist and 9.87 ± 0.92 N for the Amplatz. This was 7.84 ± 0.52 N for the Radifocus wire in standard configuration, which increased to 15.48 ± 0.33 N when the Radifocus wire was in pullthrough configuration. This was significantly higher than both the Lunderquist and Amplatz Super Stiff wires (p < .001, one way analysis of variance).

Conclusion

This study affirmed that a pullthrough wire becomes functionally more rigid than typical stiff wires used for endovascular procedures, and it is this stiffness that allows device delivery.

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Tortuous aortic anatomy can hinder device delivery.

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Aortic tortuosity can be straightened by using pull through wires.

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Pull through wires effectively function as stiff wires.

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Effective pull through wire stiffness is an unassessed entity.

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Pull through wires are shown to be functionally stiffer than stiff wires.

Are All Wires Created the Same? A Quality Assurance Study of the Stiffness of Wires Typically Employed During Endovascular Surgery Using Tension Dynamometry

Objective

There have only been a few studies on the stiffness and load bearing characteristics of guidewires used to deliver devices during endovascular procedures, particularly endovascular aneurysm repair. The aim of this study was to compare the load bearing characteristics of typical stiff and floppy wires, including in the context of consistency for each wire type.

Methods

Two sets of stiff guidewires (Lunderquist Extra-Stiff and Amplatz Super Stiff [0.035” × 260 cm]), were compared with a floppy hydrophilic guidewire (Radifocus Stiff M [0.035” × 260 cm]). Radial stiffness was defined as the force (newtons [N]) needed to deform the wires on an electromechanical dynamometer. Tests were repeated with three runs on three sets of the same wire to check for consistency. Data were logged on proprietary dynamometric software and peak load values assessed per wire. Peak deformation forces (PDFs) from straight configuration to midwire deformation at 15 mm was translated into Microsoft Excel for statistical analysis in Minitab 19 for Windows.

Results

There was good agreement within each wire set, with no difference in PDFs from runs for each wire (p > .10). Mean ± standard deviation PDFs were 7.83 ± 0.23 N for the Lunderquist, 9.87 ± 0.92 N for the Amplatz, and 7.84 ± 0.52 N for the Radifocus wires. The Amplatz wire exhibited the greatest resistance to deformation vs. both the Lunderquist and Radifocus wires (p < .001, one way analysis of variance). Both Amplatz and Radifocus wires had non-linear deformation characteristics.

Conclusion

This study confirmed that the represented hydrophilic wire is more deformable than the stiff wires. The Amplatz wire has complex construction features that yielded surprising baseline stiffness characteristics. The linear stiffness characteristics of the Lunderquist wire possibly contribute to it being the preferred choice for large endograft delivery.

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A range of stiff and floppy wires are used in endovascular procedures.

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Very few studies have assessed wire stiffness characteristics.

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No study has undertaken external quality assurance analyses of wire stiffness.

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This study confirms consistent wire stiffness characteristics.

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Predictable Lunderquist wire stiffness supports its choice for device delivery.

Comparing polymer-filled versus self-expanding endografts in Chinese patients

INTRODUCTION

We performed a single-center nonrandomized study on patients who underwent endovascular aneurysm repair using polymer-filled or other self-expanding endografts.

METHODS

Consecutive patients with asymptomatic infrarenal abdominal aortic aneurysms who underwent endovascular repair were retrospectively reviewed. They were divided into a polymer-filled ( n = 20) or self-expanding group ( n = 42). Baseline characteristics, operative mortality and morbidity, and follow-up data were compared.

RESULTS

Aneurysm diameter, neck and iliac morphologies did not differ between the two groups. Technical success was 100%. The 30-day mortality was 0% and 2.4% in the polymer-filled and self-expanding group, respectively. At a mean follow-up of 17 months, the changes in sac size were -2.1 mm and -5.1 mm ( p = 0.144) at one year, and -3.5 mm and -7.7 mm ( p = 0.287) at 2 years in the polymer-filled and self-expanding group, respectively. The polymer-filled group had 7 (35%) type II endoleaks, and the self-expanding group had 1 (2.4%) type Ia and 13 (31%) type II endoleaks. Neck diameter remained stable in the polymer-filled stent-grafts whereas there was progressive neck degeneration in the self-expanding group. The rates of reintervention and overall survival were similar in both groups. The presence of an endoleak was the only predictor of non-regression of the aneurysm (odds ratio = 17.00, 95% confidence interval: 4.46-64.88, p < 0.001).

CONCLUSION

Polymer-filled endografts had similar safety, effectiveness, and durability to other self-expanding endografts. The major advantage is the small iliofemoral access. They also have the potential long-term benefit of a more stable neck.

Management of Difficult Access during Endovascular Aneurysm Repair

BACKGROUND

To describe a large single-institutional experience in managing challenging access situations during endovascular aneurysm repair (EVAR).

METHODS

Data from all patients undergoing EVAR at a tertiary academic medical center between 2009 and 2013 were collected retrospectively, including demographics, size of iliac arteries, type of device used, approach to managing difficult access (DA), and outcomes. The median follow-up was 38 months. DA was defined as iliac arteries with a diameter of less than 7 mm bilaterally. Fenestrated and snorkel repairs were excluded.

RESULTS

Of 400 EVARs performed during the study period, 191 (48%) were done in patients with DA. Of the DA patients, 35 (18.3%) underwent 42 adjuncts before the introduction of the main body device: including 15 dilators, 11 balloon angioplasties, 9 aortouniiliac devices, 3 SoloPath sheaths, 1 retroperitoneal cutdown, and 3 iliac stents. In another 29 patients, iliac stents were used to correct stenoses or kinks in the limbs after EVAR devices were deployed. The average diameter of the iliac artery used to deliver main body component was 4.6 mm in the group of patients requiring adjuncts and 5.4 mm in the remainder of the patients with small iliac arteries (P = 0.008). The median size of the main body device was 28 mm. Two cases were aborted due to inability to deliver the device. Other complications included 7 (3.6%) iliac ruptures, 3 (1.6%) instances of limb ischemia, and 5 (2.6%) patients needed early reoperation (within 30 days). Two patients (1%) had type I endoleaks at the conclusion of EVAR. During follow-up, 12 (6.3%) patients required EVAR revisions. Seven patients (3.6%) had limb thrombosis which occurred only in patients who did not have adjective procedures during the initial EVAR. Limb thrombosis and rate of revisions in patients with DA were not significantly different from the rates observed in non-DA patients. Perioperative mortality after elective repairs was 1.6% in DA patients and 0% in non-DA patients (P = 0.12).

CONCLUSIONS

EVAR can be successfully performed in patients with bilateral small iliac arteries. Adjunctive procedures might increase the technical success rate of EVAR in these patients and should definitely be considered in patients with iliac arteries less than 5 mm in diameter. Next generation and "low-profile" devices might minimize the need for adjunctive procedures and facilitate EVAR in these patients.

“Paving and Cracking”: An Endovascular Technique to Facilitate the Introduction of Aortic Stent-Grafts through Stenosed Iliac Arteries

Purpose:

To describe a technique that facilitates the safe introduction of aortic stent-grafts through diseased iliac arteries.

Technique:

The technique involves relining and dilating (“paving and cracking”) stenosed iliac arteries with covered stents prior to the introduction of the main aortic stent-graft. It has been successfully used to introduce aortic stent-grafts in patients where other transfemoral endovascular measures have failed.

Conclusion:

This technique increases the applicability of transfemoral EVAR and prevents serious complications as a result of access-related damage to the iliac arteries.

Conduit-Free Retroperitoneal Access to the Iliac Artery in Endovascular Aortic Repair in Patients With Improper Access Vessels

Successful endovascular aortic repair is highly dependent on the quality of the iliac access vessels. Patients with poor access vessels can be turned down from endovascular aortic repair or thoracic endovascular aortic repair by the treating physician. Perioperative complications such as failure to deliver the device or iliac rupture can be addressed to improper access vessels. In this article, we describe a novel technique to access the common iliac artery when access vessels are poor in diameter or quality. This sutureless conduit-free access technique can be used in TEVAR or EVAR and requires less surgical exposure of the iliac arteries.

The impact of concomitant procedures during endovascular abdominal aortic aneurysm repair on perioperative outcomes

BACKGROUND

Concomitant procedures during endovascular aneurysm repair (EVAR) of an abdominal aortic aneurysm are performed to facilitate endograft delivery, to simultaneously treat unrelated conditions, or to resolve intraoperative pitfalls. The frequency and perioperative impact of these procedures are not well described. This study aimed to assess the frequency and perioperative impact of various concomitant procedures performed at the time of EVAR.

METHODS

We included all elective EVARs in the Vascular Study Group of New England between January 2003 and November 2014 and identified those with and those without concomitant procedures. Multivariable logistic regression analysis was used to establish the independent association between concomitant procedures and perioperative outcomes.

RESULTS

The study included 4033 patients, with 1168 (29.0%) patients undergoing one or more additional procedures. Independent risk factors for 30-day mortality were concomitant femoral endarterectomy (odds ratio [OR], 4.8; 95% confidence interval [CI], 2.1-11.2) and renal angioplasty or stenting (OR, 3.1; 95% CI, 1.2-8.3). Postoperative bowel ischemia was associated with hypogastric embolization (OR, 3.8; 95% CI, 1.1-13.4) and iliac angioplasty or stenting (OR, 3.5; 95% CI, 1.3-9.6). Leg ischemia was associated with unplanned graft extension (OR, 2.3; 95% CI, 1.02-5.0), other artery reconstruction (OR, 5.2; 95% CI, 1.8-15.1), thromboembolectomy (OR, 5.2; 95% CI, 1.3-20.8), and repair of arterial injury (OR, 4.6; 95% CI, 1.2-18.3). Risk factors for deterioration of renal function were iliofemoral bypass (OR, 3.9; 95% CI, 1.3-12.2), other artery reconstruction (OR, 2.7; 95% CI, 1.3-5.8), renal angioplasty or stenting (OR, 2.5; 95% CI, 1.3-4.6), and repair of arterial injury (OR, 4.5; 95% CI, 1.6-12.2). Myocardial infarction was associated with femorofemoral bypass (OR, 3.9; 95% CI, 1.7-8.7), other artery reconstruction (OR, 3.9; 95% CI, 1.6-9.2), and repair of arterial injury (OR, 6.1; 95% CI, 1.8-21.0). Wound complications were predicted by femorofemoral bypass (OR, 13.4; 95% CI, 5.8-31.1).

CONCLUSIONS

Concomitant procedures during EVAR are associated with increased postoperative morbidity and mortality. The need for performing concomitant procedures should be carefully considered. The morbidity associated with intraoperative complications highlights the importance of avoidance of arterial injury and thromboembolic events where possible.

Contralateral acute lower limb ischaemia following total hip replacement in a patient with an endovascular abdominal aortic aneurysm repair

Total hip replacement (THR) is a common procedure to treat patients with a fractured neck of femur. Ipsilateral major vessel injury with acute lower limb ischaemia is a rare but potentially devastating complication. Contralateral acute limb ischaemia is unreported. We present the case of a contralateral, acute lower limb ischaemia following THR for a fractured neck of femur in the presence of an endovascular aortic aneurysm repair (EVAR) and femoro-femoral crossover grafts. We advise early vascular surgery consultation for patients undergoing THR with an EVAR stentgraft in situ to help minimize risks of peri- and postoperative graft occlusion and consequent acute lower limb ischaemia.

Thoracic aneurysm repair: managing severe tortuosity with brachiofemoral traction

Challenging anatomy of the thoracic aorta is often encountered, and aortic tortuosity may be a major impediment to the propulsion of the stent-graft. Traction on both ends of a guidewire, with one end exiting the right upper extremity and the other end exiting the lower extremity, is an excellent option to manage thoracic aorta tortuosity. Careful application of simple guidelines may lessen associated risks and improve safety.

Access for Endovascular Aneurysm Repair

Despite advancement in stent-graft technology, access-related problems continue to occur during endovascular repair of aortic aneurysms. Various techniques have been adopted to overcome difficult access situations, however. To survey these developments in arterial access, we performed a systematic literature review from 1994 through 2005 to identify relevant articles pertaining to endovascular access techniques and complications. Excessive iliac tortuosity, circumferential vessel wall calcification, significant occlusive disease, and small caliber vessels account for the majority of access problems, most of which are readily apparent with adequate baseline imaging. Even with careful preoperative assessment, however, some access problems may not be foreseen; nonetheless, the majority can be overcome using today's array of ancillary procedures, such as an iliac conduit, a brachiofemoral wire, or arterial reconstruction. Alternatively, other approach routes, such as the common carotid artery or direct aortic access, may be used to facilitate endovascular aneurysm repair.

Endovascular treatment for aortic disease: Is a surgical environment necessary?

OBJECTIVE

Interventional radiologists, cardiologists, and vascular surgeons are capable of performing endovascular procedures successfully in their respective environments. Suboptimal anatomy or intraoperative technical problems can be encountered, and endovascular management alone is not always suitable. The objectives of this study were to define the incidence of adjunctive surgical techniques, to discuss the rationale for endovascular reconstruction in a well-developed surgical environment, and to assess the effect of experience on the incidence of adjunctive repair.

METHODS

All primary aortic and aortoiliac elective, urgent, and emergent endovascular procedures performed at the Peter Lougheed Center and entered into a prospective database from May 25, 1999 to June 01, 2005, were reviewed. All adjunctive surgical techniques to enable stent deployment, enhance attachment site, or solve intraoperative difficulties were captured. The study period was divided into two time periods based on learning curve data to assess the effect of experience on the rate of adjunctive repairs.

RESULTS

Four hundred thirty-eight patients underwent elective (80%), urgent (15%), or emergent (5%) endovascular procedures during the study period. These consisted of 101 thoracic and 337 abdominal operations, including the use of 13 fenestrated stents. One hundred thirty-nine patients (31.7%) required 180 open surgical procedures. Complete data were available for the entire patient cohort. The mean follow-up was 793.2 days (SD, 519.1 days). Procedures were necessary for vascular access, arterial dissection/rupture, limb ischemia, and enhancement/elongation of the stent attachment site. The persistent endoleak rate was 5.3%, the late rupture rate was 0.7%, the conversion rate was 1.6%, the 30-day surgical mortality rate was 3.2%, all-cause mortality to date is 7.3%, and the reintervention rate was 4.6%. There was no statistically significant effect of the learning curve on the incidence of surgical adjunctive procedures in either the thoracic group (11/26 [42.3%] for phase 1 vs 17/75 [22.6%] for phase 2) or the abdominal group (14/50 [28.0%] for phase 1 vs 97/287 [33.8%] for phase 2). Overall, 31.5% of patients required adjunctive surgical repair.

CONCLUSIONS

Successful endografting requires endovascular expertise in addition to a well-developed surgical environment to increase applicability and decrease patient risk. Despite advances in endovascular technology, hybrid techniques will continue to be required to achieve good overall success rates.

Adjuvant Procedures Performed During Endovascular Repair of Abdominal Aortic Aneurysm. Does it Influence Outcome?

OBJECTIVE

The purpose of this study was to assess whether there is a difference in outcome of endovascular repair in patients with and without intraoperative adjuvant procedures.

METHODS

Demographic, anatomic and operative details were assessed in patients undergoing endovascular repair using the EUROSTAR registry and correlated with morbidity and mortality rates. Three groups of adjuvant procedures: (A) endovascular, (B) surgical peripheral arterial and (C) surgical abdominal arterial were compared with a group of patients without an adjuvant procedure (D). Logistic regression and Cox proportional hazards model were used for statistical analysis.

RESULTS

Of 4631 endovascular repairs, 1353 patients (29.2%) required adjuvant procedures. Additional endovascular procedures were performed in 1057 (78.1%), surgical peripheral arterial in 193 (14.3%) and surgical abdominal arterial in 103 (7.6%). The 30-day mortality rate was significantly higher in categories with peripheral arterial surgical (6.7%) and abdominal surgical procedures (7.8%) compared to patients without adjuvant procedures (1.5%, p = .001 and p = .004, respectively). Life-table-analysis demonstrated that late mortality, conversion or rupture rates were not increased in patients with an adjuvant procedure.

CONCLUSION

Adjuvant surgical procedures were associated with increased 30-day mortality. Because of this higher risk, endovascular repair should be recommended with caution when surgical adjuvant procedures are anticipated.

ENDOVASCULAR ABDOMINAL AORTIC ANEURYSM REPAIR: A 7 YEAR EXPERIENCE AT THE LAUNCESTON GENERAL HOSPITAL

BACKGROUND

To review our 7 year experience of endovascular abdominal aortic aneurysm repair (EVR) and to compare this to open repair (OR) during the same time period.

METHODS

One hundred and one EVR and 65 OR patients were studied. Parameters analysed included patient and procedure details, intensive care unit (ICU) and hospital admission time, and morbidity and mortality with particular emphasis on procedure-related problems.

RESULTS

Endovascular grafts were deployed with successful abdominal aortic aneurysm (AAA) exclusion in 100 patients. Primary technical success was achieved in 84%, clinical success in 86% and secondary success in 90% of cases. Complications occurred in 63% and 88% of EVR and OR patients, respectively. Early device-related complications occurred in 40 EVR patients (40%); 24 (60%) were corrected immediately by further stenting. Late device-related complications occurred in 15 EVR patients (15%); four (27%) required additional stenting. Most of the complications in the OR group were systemic (89%) resulting in longer ICU and hospital stays (median 48 vs 17 h and 13 vs 4 days for OR and EVR, respectively). Death within 30 days of the procedure occurred in three EVR patients. There was no perioperative mortality in the OR group.

CONCLUSION

Endovascular AAA repair can be undertaken successfully in a district general hospital. The majority of local and device-related complications can be corrected immediately, while those persisting beyond the initial procedure usually resolve spontaneously. EVR offers a minimally invasive approach to a problem that in the past has involved major surgery.

Endoleak after endovascular repair of abdominal aortic aneurysm

PURPOSE

We sought to assess the role of endovascular techniques in the management of perigraft flow (endoleak) after endovascular repair of an abdominal aortic aneurysm.

METHOD

We performed endovascular repair of abdominal aortic aneurysm in 114 patients, using a variety of Gianturco Z-stent-based prostheses. Results were evaluated with contrast-enhanced computed tomography (CT) at 3 days, 3 months, 6 months, 12 months, and every year after the operation. An endoleak that occurred 3 days after operation led to repeat CT scanning at 2 weeks, followed by angiography and attempted endovascular treatment.

RESULTS

Endoleak was seen on the first postoperative CT scan in 21 (18%) patients and was still present at 2 weeks in 14 (12%). On the basis of angiographic localization of the inflow, the endoleak was pure type I in 3 cases, pure type II in 9, and mixed-pattern in 2. Of the 5 type I endoleaks, 3 were proximal and 2 were distal. All five resolved after endovascular implantation of additional stent-grafts, stents, and embolization coils. Although inferior mesenteric artery embolization was successful in 6 of 7 cases and lumbar embolization was successful in 4 of 7, only 1 of 11 primary type II endoleaks was shown to be resolved on CT scanning. There were no type III or type IV endoleaks (through the stent-graft). Endoleak was associated with aneurysm dilation two cases. In both cases, the aneurysm diameter stabilized after coil embolization of the inferior mesenteric artery. There were two secondary (delayed) endoleaks; one type I and one type II. The secondary type I endoleak and the associated aneurysm rupture were treated by use of an additional stent-graft. The secondary type II endoleak was not treated.

CONCLUSIONS

Type I endoleaks represent a persistent risk of aneurysm rupture and should be treated promptly by endovascular means. Type II leaks are less dangerous and more difficult to treat, but coil embolization of feeding arteries may be warranted when leakage is associated with aneurysm enlargement.