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Page 4 of 16 Gomes et al. Vessel Plus 2023;7:24 https://dx.doi.org/10.20517/2574-1209.2023.60

Table 2. Main risk factors that contribute to the pathophysiology of SCI in the context of thoracic and thoracoabdominal aneurysms
surgery

Demographics: age above 70 years, renal function impairment, hypertension, chronic obstructive pulmonary disease, and diabetes mellitus [26,27]
Aortic cross-clamping and unclamping: produces hypertension proximal to the clamp, increased central venous pressure, and distal
hypotension, which combined, produce spinal cord ischemia [28,29] . Prolonged cross-clamping [30] increases the risk of SCI even more
Other surgical risk factors: Extent II TAAA [27] , emergent presentation with a ruptured aneurysm, presence of dissection [30] , prior or
concomitant AAA surgery, the extension of the aortic repair, excessive intraoperative blood loss, long duration of the procedure, and coverage of
[31]
the subclavian and hypogastric arteries, especially if more than two vascular independent territories will be compromised
[31]
Extensive aortic coverage in endovascular procedures: Produces obliteration of multiple segmental arteries , which is specifically concerning
[32,33]
during endovascular repair because intercostals cannot be surgically reimplanted
Perioperative hypotension [34-36] : with mean arterial pressure < 70 mmHg
Presence of lower density mural thrombus/plaque in the descending thoracic aorta: risk factor for microembolism [37]
Atheroemboli [38]
occlusion of spinal cord feeding vessels with air [39]

[46]
LSA coverage with no prior revascularization . Buth et al., in a multicenter study including 606 patients
with aneurysm or dissection, observed an independent correlation between SCI and LSA coverage after
repair with an odds ratio of 3.9 (P = 0.027), confirming the importance of the LSA patency in the context of
SCI risk . The most common strategies to preserve the flow to the left subclavian artery include LSA to left
[47]
[48]
common carotid artery (LCCA) transposition, LCCA-LSA bypass , and, more recently, thoracic branched
grafts .
[49]
Conversely, other studies report that LSA coverage is well tolerated during TEVAR procedures, even
without revascularization. In a retrospective multicenter study including 1,189 patients submitted to
TEVAR for the treatment of TAA, Maldonado et al. concluded that LSA revascularization was not
protective against SCI, and reported an increased risk of cerebrovascular accidents in female patients
submitted to LSA revascularization . Riesenman et al., in a retrospective analysis including 112 TEVAR
[50]
patients, did not report SCI events among the 24 cases with endograft implanted in zone 2, even though
none of them underwent LSA revascularization . Coverage of the LSA is contraindicated without prior
[51]
revascularization in situations such as the presence of a dominant left vertebral artery . It is also critical to
[51]
evaluate the contribution from the circle of Willis’ anatomy during the surgical planning of procedures that
involve the subclavian arteries. Table 3 summarizes the SVS recommendations for LSA revascularization in
the context of TEVAR with LSA coverage.

Hypogastric artery patency relevance
The patency of the hypogastric arteries plays a vital role in the context of SCI risk factors, especially in
patients submitted to extensive aortic repair, as these arteries significantly contribute to the perfusion of the
distal spinal cord . Picone et al., described seven patients who developed spinal cord ischemia after
[53]
abdominal aortic surgeries, five of whom had unilateral or bilateral hypogastric occlusion during the
procedures . Eagleton et al., in a study including TEVAR (n = 201), FEVAR (n = 227), BEVAR (n = 472),
[54]
and EVAR (351), reported an incidence of SCI of 2.8% (n = 36) . Of these affected patients, fourteen had
[55]
preoperative unilateral or bilateral hypogastric occlusion, and seven had coverage of at least one hypogastric
artery during the endovascular procedure, highlighting the relevance of the internal iliac arteries patency in
the overall risk of SCI.

The importance of preserving hypogastric perfusion cannot be stressed enough. For over a decade now, iliac
branched grafts have been used as a safe and successful strategy of antegrade blood flow preservation to the
hypogastric arteries during aortic surgery in those cases with aneurysmal degeneration affecting the iliac