Reducing complications by better case selection: Anatomic considerations

https://doi.org/10.1053/j.semvascsurg.2004.09.006Get rights and content

The feasibility of endovascular aortic aneurysm repair (EVAR) in any individual patient remains inherently dependent on the anatomy of the aorta and iliac arteries. There is a great deal of evidence in the literature that poor anatomic patient selection for EVAR will increase the risk of both procedure-related complications and compromised long-term outcomes. Inferior outcomes can include technical failures such as attachment-site endoleak, endograft migration, and ultimately aneurysm growth and rupture. Unfortunately, it is relatively rare to encounter a patient who possesses completely “ideal” anatomy for this technique. With the broadening spectrum of new devices applicable for the intraluminal treatment of abdominal aortic aneurysms, the vascular surgeon is challenged to be aware of individual selection criteria for the ever-widening variety of endoluminal grafts, in order to choose the optimal device for each patient’s distinct anatomical situation. In patients who would otherwise be at high risk for traditional abdominal aortic aneurysm surgery based on medical comorbidities, the additional challenge for the practitioner who performs EVAR is to possess excellent judgment regarding just how far the anatomical “envelope” may be pushed without compromising patient outcomes.

Section snippets

Proximal anatomy

Complete hemodynamic sealing at the proximal endograft attachment site and secure endograft fixation are absolute requirements for complete aneurysm exclusion.4 Anatomic characteristics of the proximal aortic neck influence both the effectiveness of aneurysm exclusion and the durability of attachment.6 Failure of proper attachment and sealing at the proximal neck predisposes toward complete technical failure, resulting in a proximal attachment-site leak and/or distal migration. Inadequate

Distal aortic neck anatomy

Specific information regarding length, diameter, and characteristics of the distal aortic neck were probably more important when endografts in an aorto-aortic tube configuration were used. Currently, tube stent-grafts have all but been abandoned in favor of bifurcated, or aorto-uni-iliac, devices when necessary. However, the nature of the distal aorta still plays a role in selection criteria and outcomes. Some patients have an extremely narrow distal aortic lumen, which is often the result of

Iliac anatomy

Iliac artery anatomy probably represents the greatest anatomical influence on short-term morbidity following EVAR.4 Iliac artery morphology is essential to obtaining delivery device access into the aorta, sealing the aneurysm to prevent distal attachment-site endoleaks, and maintaining adequate perfusion to the pelvis.4, 6 Critically important factors related to iliac artery anatomy include tortuosity, intraluminal diameter, calcification, and presence of iliac artery aneurysmal disease. In

Do smaller aneurysms have better results with EVAR?

At the author’s institution, an unexpected finding in our analysis of the contribution of anatomic factors to poor outcome following EVAR was the apparent effect of preoperative AAA diameter.2 Multivariate analysis revealed both the preoperative maximum aneurysm diameter and the proximal neck length to be independent predictors of attachment-site leak, despite the interrelationship of these factors. Specifically, in AAAs less than 5 cm in diameter, the incidence of all endoleaks was 8.3%,

Conclusion

In conclusion, although proper anatomic selection is critical in obtaining good outcomes following endovascular aneurysm repair, it is difficult to define strict inclusion criteria to an absolute degree. Although generally accepted guidelines certainly exist, the vascular surgeon must use excellent judgment to realize a compromise between extremely rigorous inclusion criteria that would exclude a large number of patients, and being too willing to tolerate unacceptable anatomy, which would

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  • Technical Success and Long-Term Results with Excluder/C3 Endoprosthesis in Narrow Aortic Bifurcations: First Italian Multicentre Experience

    2018, Annals of Vascular Surgery
    Citation Excerpt :

    These features, now considered essential for the patient's eligibility to EVAR, are widely described in international literature17,18 and refer principally to the following issues: proximal aortic neck region, aortic tortuosity index, presence and patency of aortic branch vessels, iliac artery anatomy, degree of calcification and thrombosis at the device's landing points, and hypogastric arteries patency. Moreover, several predictive factors for EVAR failure have been clearly recognized and studied, as there is great evidence that poor anatomic patient selection based on these criteria would imply greater risk for procedure-related complications and poor long-term outcomes.6 Strong correlation was found between specific anatomic features outside of these criteria and technical failures such as attachment-site EL,7,19 endograft migration,20 and even limb occlusion.21,22

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