Although endovascular treatment of thoracic aneurysms is typically less invasive than open surgical repair, preparation for possible open repair must be undertaken in longer, complex cases with more bleeding. General and regional anesthetic techniques have been described, but general anesthesia remains the most popular anesthetic technique for TEVAR. General anesthesia facilitates neuromonitoring and, if need be, TEE monitoring, as well as immobility to improve intraoperative angiographic imaging and provide stability during endograft deployment.

Induction: As for open repair, avoidance of hypertension, tachycardia, and increased stress on the aneurysm is key.

IV Access: Routine use of central venous access is recommended to facilitate the rapid transfusion of IV fluids and blood products, as well as the use of vasoactive medications. As for open repair, placement of a preinduction arterial catheter is necessary for close continuous monitoring of arterial blood pressure. The location of the arterial line should be discussed with the vascular surgeon, as it may vary depending on the surgical approach and landing zones of the TEVAR. For example, coverage of the left subclavian arterial takeoff by the endograft or surgical placement of an angiography catheter into the left brachial artery can necessitate right radial arterial cannulation. If monitoring of arterial pressure distal to the endograft is necessary, femoral arterial access may be established and transduced simultaneously with the radial arterial line for a comparison of pressures.

Spinal cord protection: The risk of spinal cord ischemia can be mitigated with the placement of CSF drains in high-risk patients, such as those with a history of aortic repair and extent I to III thoracoabdominal aneurysms, as well as those who require graft coverage of extensive portions of the aorta. Prophylactic placement of CSF drains in lower-risk elective TEVARs remains controversial and, thus, requires consideration of whether the benefits outweigh the risks. CSF is drained to typically maintain a CSF pressure less than 10 to 15 mm Hg, without exceeding a maximal drainage rate of 20 to 25 mL/h, as well as an SCPP greater than or equal to 70 mm Hg.

Neuromonitoring with SSEPs and MEPs may be used to assess the integrity of spinal cord pathways and global spinal cord perfusion. For instance, a reduction in 50% to 75% from baseline amplitude merits further augmentation of SCPP by raising MAP to greater than 90 to 100 mm Hg and reducing CSF pressure to 5 mm Hg, according to a protocol from the Mayo Clinic. If signals do not normalize, flow to the pelvis and lower extremities should be restored and a decision is made either to place an arterial conduit prior to proceeding or to perform the procedure in stages.

Hemodynamic considerations: It is reasonable to maintain the MAP close to baseline for elective TEVARs while a lower blood pressure goal may be sought when there is a concern for aneurysm rupture or extension of an acute dissection. Vasoconstrictors and vasodilators should be readily available to allow precise titration of blood pressure. Immediately before endograft deployment, migration of the graft should be minimized using techniques such as induced hypotension, rapid ventricular pacing, adenosine-induced cardiac arrest, and right atrial-inferior vena cava balloon occlusion. This results in significant transient hemodynamic instability, particularly if the patient has poor cardiac function. Transient balloon occlusion of the aorta during deployment can have a similar effect. After deployment, it is reasonable to target a MAP of 85 to 100 mm Hg to achieve an SCPP greater than or equal to 70 mm Hg. The indication for TEVAR helps determine the precise blood pressure target; hypertension is well tolerated after repair of degenerative aneurysms, but it can lead to exacerbation of residual dissection after repair of TBADs.

TEE: TEE can be used to guide vascular access by visualizing the placement of wires and to ensure the exclusion of aortic pathology by the endograft. Once the endograft is deployed, TEE can be used to evaluate for endoleaks and rule out the occurrence of retrograde dissection.

References

• Chatterjee S, Preventza O, Orozco-Sevilla V, Coselli JS. Perioperative management of patients undergoing thoracic endovascular repair. Ann Cardiothorac Surg. 2021;10:768-777.
• Cheruku S, Huang N, Meinhardt K, Aguirre M. Anesthetic management for endovascular repair of the thoracic aorta. Anesthesiol Clin. 2019;37:593-607.
• Isselbacher EM, Preventza O, Hamilton Black J 3rd, et al; Peer Review Committee Members. 2022 ACC/AHA guideline for the diagnosis and management of aortic disease: a report of the American Heart Association/American College of Cardiology Joint Committee on clinical practice guidelines. Circulation. 2022;146:e334-e482.
• Nation DA, Wang GJ. TEVAR: endovascular repair of the thoracic aorta. Semin Intervent Radiol. 2015;32: 265-271.
• Pulido JN, Wittwer ED, Baker AC, Oderich GS. Anesthetic considerations for complex endovascular aortic repair. In: Oderich GS, ed. Endovascular Aortic Repair: Current Techniques with Fenestrated, Branched and Parallel Stent-Grafts. Springer International Publishing; 2017.