Optimal Anesthetic Technique for Aortic Arch Surgery

Anesthetic Foundations

• General anesthesia with multisite invasive hemodynamic monitoring, transesophageal echocardiography, and a comprehensive cerebral‑protective strategy that includes hypothermia with circulatory arrest and selective antegrade cerebral perfusion is required for aortic arch repair. 1
• General anesthesia is mandatory because aortic arch surgery requires cardiopulmonary bypass, deep hypothermia, and circulatory arrest. 2

Hemodynamic and Temperature Monitoring

• Invasive arterial pressure monitoring at one or more sites, positioned proximal to aortic clamping zones, should be employed according to the planned cannulation and perfusion strategy. 1
• Core temperature must be measured at two sites: one reflecting cerebral/central temperature (e.g., esophageal, tympanic, nasopharyngeal) and a second reflecting visceral temperature (e.g., bladder or rectal). 1

Intra‑operative Imaging and Neurophysiology

• Transesophageal echocardiography is recommended for all open thoracic aortic repairs unless specific contraindications exist; it provides continuous monitoring, procedural guidance, and detection of graft leaks. 2
• Motor and somatosensory evoked potentials may be employed when the data help guide intra‑operative therapy. 2
• Bilateral near‑infrared spectroscopy (NIRS) should be used during hypothermic circulatory arrest to monitor cerebral oxygenation. 3
• Transcranial Doppler ultrasound can be considered for individualized cerebral perfusion management and emboli detection. 3

Cerebral Protection Strategies

• Deep hypothermic circulatory arrest, selective antegrade cerebral perfusion, and retrograde cerebral perfusion are each reasonable—alone or in combination—to minimize brain injury; the choice should reflect institutional experience. 4
• Cerebral hypothermia is achieved via extracorporeal circulation at temperatures ranging from 12 °C to 30 °C. 4
• Moderate hypothermic circulatory arrest (20.1 °C–28 °C) combined with selective antegrade cerebral perfusion is recommended for arch reconstruction. 3
• Retrograde cerebral perfusion via the jugular vein is performed at a perfusion pressure of 20–40 mm Hg under hypothermic conditions. 4
• Antegrade cerebral perfusion is delivered at a pressure of 50–80 mm Hg through direct cannulation of the brachiocephalic vessels, a lateral graft to the axillary artery, or direct graft cannulation. 4
• Antegrade arterial cannulation (e.g., axillary cannulation) is preferred over retrograde cannulation for systemic perfusion during aortic arch surgery. 3
• Peri‑operative cerebral hyperthermia is contraindicated; rewarming should be performed gradually to avoid hyperthermia. 4

Antifibrinolytic Therapy

• Routine use of antifibrinolytic agents (ε‑aminocaproic acid or tranexamic acid) is supported by strong evidence from other cardiac‑surgery studies and is recommended for aortic arch procedures. 4
• Tranexamic acid dosing of a 10 mg/kg loading dose followed by a 1 mg/kg/h infusion achieves plasma levels sufficient to inhibit fibrinolysis. 4

Regional Anesthesia and Airway Management

• Regional anesthetic techniques are not recommended in patients at risk for neuraxial hematoma due to antiplatelet agents, low‑molecular‑weight heparin, or significant anticoagulation required for cardiopulmonary bypass. 2
• Routine exchange of double‑lumen endotracheal tubes for single‑lumen tubes at the end of complex surgery is discouraged when significant upper‑airway edema or hemorrhage is present; the decision should follow careful assessment of airway swelling. 2

Additional Peri‑operative Considerations

• Alpha‑stat acid‑base management should be employed in adult cardiac surgery patients undergoing moderate‑to‑high hypothermia to improve neurological outcomes. 3
• Peri‑operative magnesium sulfate may be used for prophylaxis of postoperative arrhythmias and to enhance cardiac protection. 3
• The cardiopulmonary bypass circuit should remain functional until chest closure is completed. 3

Arterial Pressure Monitoring and Cannulation Strategies in Aortic Arch Surgery

Arterial Pressure Monitoring

• Bilateral invasive arterial pressure monitoring is mandatory – a right radial line plus either a left radial (or brachial) line or a femoral line is required to verify endoaortic balloon position and to assess cerebral perfusion throughout the procedure. 5
• Right radial artery is the preferred primary monitoring site for all aortic arch operations. [5][6]7
• Left radial or left brachial artery is the preferred secondary site, with the femoral artery as an acceptable alternative when needed. [5][6]7
• Bilateral monitoring enables detection of cerebral mal‑perfusion during cannulation and selective cerebral perfusion phases. 8
• Distal (systemic) perfusion can be continuously assessed during cardiopulmonary bypass using the second arterial line. 7

Cannulation Site Selection

• Right axillary artery cannulation is the preferred arterial inflow for cardiopulmonary bypass in aortic arch surgery because it provides physiological antegrade perfusion, reduces stroke risk, allows selective cerebral perfusion, and is associated with lower hospital mortality. [9][10]8
• Femoral artery cannulation is an alternative but is less favored due to retrograde flow, higher risk of organ mal‑perfusion, and potential limb ischemia; it should be used only when axillary access is not feasible or in emergency/anatomic constraints. [8][10]
• Direct aortic cannulation can be employed in experienced centers with comparable outcomes to axillary cannulation when guided by imaging (TEE or epiaortic ultrasound) and performed using a Seldinger technique under direct visualization. [8][5]7

Strategy‑Specific Monitoring Adjustments

• When ipsilateral axillary bypass is used, a contralateral arterial line (radial or femoral) must be placed because the ipsilateral radial line may give unreliable readings during bypass. [6][7]5
• If femoral cannulation is planned, maintain bilateral radial monitoring and add a femoral line only if femoral cannulation is anticipated. [8][6]

Special Patient Populations

• Patients with peripheral vascular disease should undergo pre‑operative non‑invasive lower‑extremity vascular assessment (and possibly CT angiography) before arterial line placement; femoral cannulation may cause limb ischemia in this group. [5][7]
• Patients with type‑A aortic dissection: avoid axillary cannulation if the axillary artery is involved in the dissection; confirm true‑lumen cannulation with imaging and consider central aortic cannulation under echocardiographic guidance. [8][6]7

Intra‑operative Imaging and Neuromonitoring

• Transesophageal echocardiography (TEE) is recommended for all open thoracic aortic repairs to provide continuous procedural guidance and to detect graft leaks or other complications. 5
• Transcranial Doppler ultrasound can be used to detect cerebral emboli during bypass, supporting individualized cerebral perfusion management. 6

Common Pitfalls to Avoid

• Do not rely on a single arterial line; unilateral monitoring is insufficient for aortic arch surgery. 5
• Do not assume the radial line on the side of axillary cannulation is reliable; plan contralateral access from the start. [6][7]
• Always perform an Allen test (or equivalent) before radial cannulation to ensure adequate palmar collateral flow. 7

Cerebral Protection Strategies During Aortic Arch Surgery

1. Techniques for Cerebral Perfusion

• Deep hypothermic circulatory arrest (DHCA), selective antegrade cerebral perfusion (SACP), and retrograde cerebral perfusion (RCP) are the three principal techniques for maintaining cerebral perfusion during deep hypothermic arrest; the choice is driven by institutional experience. 11
• The American College of Cardiology/American Heart Association/American Association for Thoracic Surgery (ACC/AHA/AATS) consider DHCA, SACP, and RCP to be reasonable methods for minimizing brain injury in aortic‑arch repair (Class IIa, Level B evidence). 12

2. Temperature Management

• Cerebral hypothermia is achieved with cardiopulmonary bypass at target temperatures between 12 °C and 30 °C. [11][13]14
• Moderate hypothermic circulatory arrest (target 20.1 °C–28 °C) combined with SACP is recommended for arch reconstruction (Class IIa, Level B). 15
• Prolonged DHCA without perfusion adjuncts (> 40–45 min) markedly raises the risk of permanent neurological injury (Class III, Level B). [11][13]14
• Rewarming must be performed at a controlled rate to avoid cerebral hyperthermia, which is contraindicated because it is likely neurotoxic (Class III, Level B). [11][13]14

3. Selective Antegrade Cerebral Perfusion (SACP)

• SACP is delivered at a perfusion pressure of 50–80 mm Hg. [11][13]14
• Preferred arterial entry is right axillary artery cannulation (often via a prosthetic side‑graft), allowing extracorporeal circulation and cooling without manipulating the diseased thoracic aorta; it can be used immediately for SACP (Class IIa, Level B). [13][16]
• Direct cannulation of the brachiocephalic arteries, or of a graft segment anastomosed to them, provides the conduit for SACP. [13][17]
• Successful unilateral SACP depends on adequate collateral flow through the circle of Willis; bilateral brachiocephalic cannulation has been reported, but evidence is insufficient to declare it superior. [13][16]
• SACP shortens cerebral ischemic time and permits moderate hypothermia (rather than deep hypothermia), which is associated with favorable clinical outcomes. [16][17]
• Most series show outcomes with any form of arterial SACP that are comparable or superior to DHCA alone or RCP. [13][16]
• A 2013 meta‑analysis demonstrated a significantly lower rate of permanent neurological dysfunction with moderate hypothermia + SACP versus deep hypothermia alone (7.3 % vs 12.8 %; p < 0.001). 18

4. Retrograde Cerebral Perfusion (RCP)

• RCP is administered via the internal jugular vein at a perfusion pressure of 20–40 mm Hg under mild or deep hypothermia. [11][13]14
• Evidence regarding RCP’s ability to meet cerebral metabolic demands and improve neurological outcomes is controversial. [11][13]14
• Some centers report that RCP maintains cerebral hypothermia and yields better outcomes when used as the primary neuroprotective strategy (Class IIa, Level B). [11][13]16

5. Intra‑operative Cerebral Monitoring

• Bilateral near‑infrared spectroscopy (NIRS) is recommended for continuous cerebral oxygenation monitoring during DHCA (Class I, Level C). 15
• Transcranial Doppler ultrasound may be employed for individualized perfusion management and emboli detection (Class IIb, Level C). 15
• Additional modalities include electroencephalography (EEG), somatosensory evoked potentials, bispectral index, and jugular venous oximetry. [11][16]

6. Arterial Cannulation Strategy

• Antegrade arterial entry (e.g., right axillary cannulation) is preferred over retrograde femoral entry for aortic‑arch repair (Class IIa, Level B). 15
• Retrograde femoral cannulation is reserved for emergencies or when anatomical constraints preclude antegrade access because it carries a higher risk of systemic malperfusion. 15

7. Acid‑Base Management

• An α‑stat acid‑base strategy is advised for adult cardiac surgery patients undergoing moderate‑to‑high hypothermia, as it is linked to improved neurological and neurocognitive outcomes (Class IIa, Level B). 15

All bullet points are derived from cited references and include the guideline class and level of evidence where provided.

Evidence‑Based Monitoring and Perfusion Targets for Selective Antegrade Cerebral Perfusion

Pressure Targets for Cerebral and Systemic Circulation

Flow Rate and Temperature Management

Anatomical Considerations Influencing Monitoring Strategy

Risks Associated with Cannulation Strategies

Summary of Monitoring Protocol

All bullet points and table entries are derived from peer‑reviewed evidence cited above.

Arterial Monitoring and Cannulation Strategies for Hemiarch Repair with Brief DHCA

Preferred Cannulation Site

• The right axillary artery is recommended as the preferred cannulation site for hemiarch repair, providing reliable systemic perfusion during cardiopulmonary bypass. 23

Risks Associated with Cannulation Choice

• When femoral artery cannulation is used, retrograde flow is associated with a higher risk of cerebral and systemic malperfusion compared with ante‑grade axillary cannulation; therefore, bilateral radial arterial monitoring is essential to detect these perfusion deficits. [23][24]

Neurological Outcomes of Brief Deep Hypothermic Circulatory Arrest

• Deep hypothermic circulatory arrest (DHCA) performed for less than 40–50 minutes results in acceptable neurological outcomes, with permanent neurological deficit rates reported between 2 % and 7 % in adult cardiac surgery cohorts. [25][26]

Guideline Recommendation on Neuro‑protection Strategies

• The 2021 consensus of the American Association for Thoracic Surgery (AATS) states that adding either antegrade cerebral perfusion (ACP) or retrograde cerebral perfusion (RCP) during circulatory arrest is reasonable (Class IIa), but does not require these techniques for brief arrest times; bilateral arterial monitoring remains mandatory regardless of the neuro‑protection method chosen. 23

Arterial Monitoring and Cannulation Strategies in Acute Type A Aortic Dissection Surgery

Risks Associated with Femoral Cannulation

• Retrograde femoral cannulation generates unpredictable flow patterns within the dissected aorta, potentially worsening organ (especially cerebral) malperfusion. This risk is observed in patients undergoing acute type A aortic dissection repair with hemiarch reconstruction. 27, 28, 29

• Femoral cannulation is linked to a significantly higher incidence of postoperative stroke compared with axillary or central aortic cannulation. Large database analyses of type A dissection repairs demonstrate this increased cerebrovascular risk. 27, 29

• At the start of cardiopulmonary bypass, bilateral radial arterial monitoring promptly reveals retrograde malperfusion caused by femoral flow. Immediate detection allows corrective measures before cerebral injury occurs. 27, 29

Guideline Recommendations on Cannulation Site

• 2021 AATS Expert Consensus: Femoral artery cannulation “may be reasonable” (Class IIb, Level B) but carries a higher stroke risk than ante‑grade strategies such as axillary or direct aortic cannulation. 30, 27, 28

• Right axillary artery cannulation is the preferred approach for hemodynamically stable patients (Class IIa, Level B), providing ante‑grade flow that reduces stroke risk and overall mortality. 30, 27, 28

• Direct aortic cannulation with imaging guidance is considered reasonable (Class IIa, Level B) and yields outcomes comparable to axillary cannulation when performed in experienced centers. 27, 28

• Femoral cannulation should be reserved for patients who are hemodynamically unstable or when anatomical constraints preclude safe ante‑grade access. This selective use aims to limit the higher stroke and malperfusion risks associated with retrograde flow. 27, 29