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Friday, March 15, 2019

Safety and durability of infrarenal aorta as distal landing zone in fenestrated or branched endograft repair for thoracoabdominal aneurysm 


Clinical Question:
Does using the infrarenal aorta as a distal landing zone, instead of iliac arteries, for fenestrated or branched endovascular aortic repair (FB-EVAR) decrease the rate of spinal cord and mesenteric ischemia?

Take-away Point:
Termination of an aortic endograft in the infrarenal aorta for fenestrated and branched EVAR is technically feasible with similar rates of paraplegia and mesenteric ischemia however more data is needed to evaluate for future type 1B endoleaks due to aortic degeneration.

Reference:
Law Y, Kölbel T, Rohlffs F, Behrendt C, Heidemann F, Debus ES, Tsilmparis N. (2018). A Safety and durability of infrarenal aorta as distal landing zone in fenestrated or branched endograft repair for thracoabdominal aneurysm. J Vasc Surg, 69(2), 334-341. doi:10.1016/j.jvs.2018.04.052

Click here for abstract

Study Design: Retrospective single-center cohort study

Funding Source: Self-funded

Setting: Department of Vascular Medicine, German Aortic Center Hamburg, University Heart Center of Hamburg, Germany

Summary


Conventional knowledge and manufacturer recommendation supports use of the iliac arteries as the distal landing zone for fenestrated and branched endovascular aneurysm repair (FB-EVAR) however there is no data in the literature to support iliac over distal aorta landing zone. This study retrospectively evaluated 40 patients who received FB-EVAR with the native infrarenal aorta as the distal landing zone. Grafts included the Zenith custom-made, Zenith T-branch and surgeon-modified endografts. Criteria for use of the infrarenal aorta included ≥2 cm of healthy infrarenal aorta, preferably free of thrombus, dissection and calcification. The distal stent graft was oversized by 15-30% diameter; in the event of a severe size mismatch of the distal stent graft modules a Giant Palmaz stent was placed to correct infolding and strengthen the connection.

No immediate or delayed type 1B endoleaks (range 0-72 months) were identified on surveillance CTA. Spinal cord ischemia occurred in 15% of patients (5 temporary and 1 permanent) and zero incidence of mesenteric ischemia, both of which are comparable to literature with iliac distal landing zones. 30-day mortality was 7.5% (sepsis, pneumonia, and multiorgan failure following laparotomy for GDA bleed). Post-operative CTA showed that 92.5% had at least 1 lumbar artery preserved and 74.2% had the IMA preserved. Of note, there was gradual degeneration of the infrarenal aorta at the stent graft landing zone, likely attributable to the aorta expanding to the size of the stent graft from the outward radial force. 


Figure 4. Denervation of infrarenal aorta and iliac arteries over time. The averaged nominal diameter of stent grafts was indicated. The error bars indicate the 95% confidence interval (CI).

Commentary


Termination of the stent graft in the infrarenal aorta for FB-EVAR is technically feasible with similar paraplegia and mesenteric ischemia rates to current reported literature on iliac landing zones. While the rates of paraplegia and mesenteric ischemia reported by the authors are comparable, they question whether their rates may be higher due to a high proportion of emergent cases. Preserving the IMA and lumbar arteries intuitively would minimize this risk. Degeneration of the infrarenal aorta at the site of the stent graft however appears problematic for younger patients as they will likely need distal extension for future type 1B endoleaks. Infrarenal aortic landing zone seems best suited for those patients at highest risk for paraplegia (long total coverage area, prior repair, etc) and mesenteric ischemia. Further work is needed however with comparison studies and longer term follow-up to determine the viability of this treatment option.

Post Author:
Nicole A. Keefe, MD
Resident Physician
Department of Radiology and Medical Imaging
University of Virginia
@NikkiKeefe

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