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

bilateral stenosis), or abnormalities in the vertebral arteries. Our current practice is changing to therapeutic
drain only.

As for the complications related to spinal drain placement, Kärkkäinen et al., in a study including 187
patients submitted to 240 procedures (F/BEVAR or first-stage TEVAR) with the prophylactic placement of
CSF drain, observed 6% of intracranial hypotension and 3% of spinal hematomas resulting in paraplegia or
[77]
transient paraparesis in 2% . A meta-analysis conducted by Rong et al. observed a polled event rate of 6.5%
for overall CSF drainage-related events and 2.5% for CSF drainage-related severe complications such as
[78]
intracranial hemorrhage, meningitis, epidural hematoma, and neurological deficits .
In light of the described complications, in some institutions, a therapeutic strategy is being considered the
[75]
best option in F/BEVAR cases , using perioperative neuromonitoring to detect SCI before the onset of
symptoms postoperatively. In some institutions, prophylactic spinal drains are placed only in high-risk
situations, such as patients with preoperative bilateral hypogastric occlusion requiring extensive repair, or
cases with prior neurological deficits. More recently, the US-ARC has advocated a therapeutic-drain-only
approach to patients undergoing endovascular TAAA repair.

Hemodynamic management for spinal cord protection during TAA And TAAA repair
To promote appropriate perfusion and oxygen delivery to the spinal cord during TAA and TAAA repair, a
cardiac index (CI) above 2.5 L/min/BSA is recommended . Attention is needed to avoid attempts of CI
[79]
increment based on excessive volume infusion or on the excessive use of vasoactive drugs. The former could
provoke elevation of the central venous pressure, which is inversely proportionate to the spinal perfusion
pressure. The latter could produce undesirable vasoconstriction in the spinal cord microcirculation .
[80]

As for blood pressure management, intraoperative hypotension is a well-known risk factor for SCI after
TAA and TAAA repair . Aucoin et al., in the aforementioned study on the SCI prevention practices
[81]
adopted by the US-ARC, report that the authors recommend permissive hypertension starting before the
index procedure . It should be maintained in the first 2 to 4 postoperative weeks, which is especially
[75]
relevant for patients that postoperatively presented reversible symptoms of SCI. To achieve this goal,
angiotensin receptor blockers and angiotensin-converting enzyme inhibitors should be withheld
preoperatively at least 48 h before surgery. As for the alfa- and beta-blockers, there was no consensus among
the PIs about discontinuing or not these medications, and in most cases, the beta-blockers were continued
throughout the perioperative period. The spinal cord perfusion pressure (SCPP) is directly proportionate to
[82]
mean arterial pressure , hence the hazardous effect of hypotension over the SCPP. A goal of SCPP > 80
mmHg is recommended. To fulfill this goal, a MAP > 90 mmHg is desired, and in cases in which a lumbar
drain has been placed preoperatively, the targeted CSF pressure should be kept at < 10 mmHg.

Optimizing hemoglobin levels perioperatively also plays a significant role in the SCI strategy. Behzadi et al.,
in a study including 174 TAA and suprarenal AAA patients submitted to either open or endovascular
repair, observed that preoperative hemoglobin < 9 mg/dL was a risk factor for the occurrence of SCI .
[83]
Perioperative hemoglobin ≥ 10 mg/dL has been reported in the literature as part of protocols for SCI
[84]
prevention in TAAA patients submitted to F/BEVAR .
Another valuable tool for spinal cord protection during aortic surgery is epidural cooling for regional spinal
cord hypothermia. Tabayashi et al., in a study including 37 patients submitted to open thoracic or
thoracoabdominal aorta replacement for TAAA or aortic dissection, concluded that epidural cooling is a
safe method of effectively reducing postoperative SCI . The authors utilized a catheter placed into the
[85]