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Page 6 of 17 Hong et al. Vessel Plus 2022;6:4 https://dx.doi.org/10.20517/2574-1209.2021.88

(2) eliminating diseased aortic tissue mitigates the risk for the subsequent formation of an island patch
aneurysm; and (3) reducing the anastomotic tension decreases the likelihood of late pseudoaneurysm
formation.

Preoperative imaging
Meticulous analysis of preoperative imaging is the mainstay of TAAA repair. We look for calcification,
dissection, and mural thrombus at potential aortic clamping and cannulation sites. Hypothermic circulatory
arrest may be necessary if no suitable proximal aortic clamping site is available because of the aneurysm or a
contained rupture. At our institution, we prefer a staged approach for treating patients with arch aneurysms
(especially those related to chronic aortic dissection), in which we perform total aortic arch replacement by
using an elephant trunk extension technique to set up the subsequent thoracoabdominal aneurysm repair.
We rarely use hypothermic circulatory arrest during thoracoabdominal aortic repair, given the ensuing
potential for coagulopathy and lung injury. The origins of important branching vessels, including the arch
vessels and intercostal, lumbar, visceral, renal, and iliofemoral arteries, are assessed with respect to the true
and false lumens. The spatial orientations of the renal and visceral arteries are considered in decision-
making about the use of an island patch or individual branching grafts. Anatomic variations of the aorta, its
branches, and the visceral organs also should be reviewed.

Preparation, monitoring, and adjuncts for spinal cord protection
Standard intravenous access is obtained by including a central line, a pulmonary artery catheter, and an
arterial line in the right upper extremity for hemodynamic monitoring. A double-lumen endobronchial tube
is used to facilitate single-lung ventilation. We have found that a bronchial blocker provides inferior lung
isolation and results in a higher incidence of postoperative pulmonary contusion due to manual retraction
of the lung. The patient’s temperature is passively cooled to mild hypothermia (32-33 °C). Core temperature
is measured in the nasopharynx. Cerebral oximetry is used to monitor cerebral perfusion throughout the
procedure.

We use a multimodal strategy to prevent spinal cord, visceral artery, and renal artery injuries during TAAA
repair. The mean arterial pressure (MAP) is kept at 70-90 mmHg, measured from the right-sided upper
extremity. In most cases, a left heart bypass (LHB) circuit with a cell saver for autotransfusion is used;
however, a complete cardiopulmonary bypass circuit is needed for cases requiring hypothermic circulatory
arrest (18-20 °C). In addition, cerebrospinal fluid (CSF) drainage is used for Crawford extent I and II TAAA
repairs, extent III repairs when iliac artery replacement is anticipated, and extent IV repairs when previous
descending thoracic aneurysm or extent I repairs are present. The CSF pressure is kept below 15 mmHg,
and CSF is drained at a maximum rate of 10 mL/h or 25 mL over 4 h. Importantly, we use passive mild
hypothermia, sequential cross-clamping, aggressive reimplantation of suitable intercostal or lumbar arteries,
cold renal solution to protect the kidneys whenever possible, and isothermic blood from the LHB circuit to
perfuse the celiac axis and superior mesenteric artery (SMA) [29-31] .

Positioning, exposure, and left heart bypass
The patient is placed in a modified right lateral decubitus position, with the upper body kept at 60 degrees
and the hips kept at 30 degrees by using a suction-deflated beanbag [Figure 4]. The left arm is positioned in
a freestyle swimming position at an angle above the shoulders. The operating table is gently flexed slightly
superior to the anterior superior iliac spine. This position allows for exposure of the TAAA and the femoral
arteries. A sigmoid skin incision is made beginning a finger breadth below the left scapula and coursing
along the seventh rib, across the costal margin, to the left of the umbilicus. The ribs are counted in the plane
deep to the serratus muscle along the spine, and the 6th intercostal space is entered. A segment of the
posterior rib may be removed to improve the exposure of the thoracic cavity.