Aortic Arch Advancement #2: CPB/ACP Strategy

Aortic arch advancement for coarctation associated with transverse arch hypoplasia is commonly performed through a median sternotomy using cardiopulmonary bypass (CPB) and selective antegrade cerebral perfusion (ACP). In contemporary practice, this strategy is favored because it allows precise reconstruction of the distal ascending aorta, transverse arch, and isthmus while reducing the cerebral ischemic burden associated with prolonged deep hypothermic circulatory arrest. At the same time, current multicenter and review data make clear that substantial inter-institutional variability remains in temperature targets, flow rates, and monitoring protocols, indicating that ACP is a dominant strategy but not yet a fully standardized one [1, 2].

1. Why this strategy is used

The technical challenge in neonatal and infant arch reconstruction is that the surgeon must create a broad, tension-free, anatomically durable repair in a region where uninterrupted systemic perfusion cannot always be maintained safely. The perfusion strategy therefore serves two simultaneous purposes:

• to provide a quiet, bloodless operative field for accurate arch reconstruction; and
• to maintain end-organ protection, especially cerebral protection, during the interval of arch interruption.

This is the fundamental rationale for combining CPB with ACP. Rather than relying exclusively on deep hypothermic circulatory arrest, many centers now favor moderate hypothermia with continuous or near-continuous cerebral perfusion, thereby attempting to balance operative exposure, neurologic protection, and systemic tolerance [1, 2].

2. Cannulation strategy: operative logic

2.1 Arterial inflow

A highly practical and widely adopted strategy is arterial cannulation through a side graft sewn to the innominate artery. This configuration offers several important operative advantages:

• it keeps the ascending aorta and proximal arch field less crowded;
• it facilitates smooth transition from full-body CPB to selective ACP;
• it minimizes repeated manipulation of a small and fragile native ascending aorta; and
• it provides a reproducible route for controlled cerebral inflow during reconstruction.

From a technical standpoint, graft-based innominate cannulation is especially attractive in neonates and small infants, where direct cannulation of native arch vessels may be less stable or may compromise exposure. Available pediatric series support innominate artery cannulation as a safe and effective approach for arch reconstruction with antegrade cerebral perfusion [3, 4].

2.2 Venous drainage

Venous drainage is usually obtained by either:

• bicaval cannulation, when intracardiac exposure, decompression, or associated intracardiac repair is important; or
• single right atrial cannulation, when the procedure is primarily arch-focused and exposure is otherwise adequate.

The choice is therefore driven less by doctrine than by operative requirements. If concomitant intracardiac work is planned, bicaval drainage is usually preferred; if reconstruction is confined to the arch and decompression is satisfactory, single right atrial drainage may be entirely appropriate.

3. Hypothermia: why moderate hypothermia is often preferred

In current neonatal and infant arch surgery, moderate hypothermia is commonly used rather than profound hypothermia. The rationale is physiologically straightforward:

• reduced metabolic demand,
• improved cerebral and systemic tolerance during reduced-flow conditions,
• shorter cooling and rewarming times,
• less coagulopathy,
• and less overall physiologic disruption than with deeper levels of hypothermia.

Importantly, however, “moderate hypothermia” is not a single universally fixed protocol. Across published neonatal arch reconstruction series, target temperatures vary substantially, reflecting differences in institutional philosophy, ACP flow strategy, hematocrit targets, acid-base management, and monitoring responses. A recent comprehensive review confirmed that variability remains significant not only in temperature selection, but also in ACP flow targets and neuromonitoring practices [2].

Accordingly, the success of the perfusion strategy depends less on one exact number than on the internal coherence of the entire protection plan: temperature, flow, pressure, hematocrit, monitoring, and reconstruction time must all work together.

4. Selective antegrade cerebral perfusion (ACP): core concept

During the arch reconstruction phase, the brachiocephalic vessels are selectively controlled and cerebral perfusion is delivered through the innominate graft. The goal of ACP is simple in principle but complex in execution: to preserve cerebral oxygen delivery while the arch is opened and reconstructed.

This technique has become a major component of modern neonatal arch surgery because it permits a more deliberate repair without requiring complete cessation of cerebral blood flow. That said, ACP should not be viewed as a binary on/off maneuver. It is better understood as a dynamic physiologic management strategy that requires continuous interpretation of pressure, flow, oxygenation, and exposure.

Key operative principles include:

• maintaining adequate cerebral inflow without overperfusion,
• avoiding excessive perfusion pressure or cerebral edema,
• ensuring that snares and clamps create the intended cerebral isolation pattern,
• and adjusting management according to real-time monitoring rather than any single static parameter.

Comparative clinical data suggest that ACP can reduce neurologic complications relative to deep hypothermic circulatory arrest, although this potential neurologic benefit may be accompanied by unresolved concerns regarding distal organ perfusion, including renal dysfunction [5]. Thus, the contemporary interpretation is nuanced: ACP is highly useful and widely accepted, but it is not free of trade-offs.

5. Monitoring: why multimodality assessment matters

No single monitor fully defines the adequacy of cerebral protection during arch reconstruction. For this reason, contemporary practice increasingly favors multimodal neuromonitoring, typically combining right radial arterial pressure, cerebral near-infrared spectroscopy (NIRS), and, when available, transcranial Doppler [2, 6].

5.1 Right radial arterial pressure

Right radial arterial pressure serves as a practical surrogate for pressure within the right brachiocephalic circulation during ACP. It is useful for confirming that perfusion pressure is present and for identifying abrupt circuit or cannulation problems. However, pressure alone does not guarantee adequate cerebral flow or oxygen delivery. A satisfactory arterial pressure tracing may coexist with inadequate tissue-level perfusion if flow, cannula position, or vascular resistance is unfavorable.

5.2 Cerebral NIRS

Cerebral NIRS provides continuous, noninvasive information regarding regional cerebral oxygenation and is particularly useful for detecting:

• inadequate oxygen delivery,
• perfusion pathway obstruction or malposition,
• and abrupt changes during clamping, snaring, cooling, or rewarming.

Experimental and clinical work has shown that NIRS is sensitive to ACP flow alteration and can detect deterioration in cerebral oxygenation as flow is reduced [6]. In practical terms, NIRS is valuable not because it gives a perfect absolute number, but because it provides continuous trend information during a highly dynamic portion of the operation.

5.3 Transcranial Doppler

Transcranial Doppler contributes information that neither arterial pressure nor NIRS can fully provide: real-time assessment of cerebral blood flow velocity. This is especially helpful when the team wants to distinguish between apparent perfusion pressure and true forward cerebral flow. In other words, Doppler helps answer whether ACP is actually delivering meaningful cerebral circulation, rather than merely generating pressure within the system [6, 7].

6. Perfusion strategy: what the literature suggests

The modern literature supports several practical conclusions.

First, ACP is now mainstream, and multicenter data show that regional or selective cerebral perfusion is used more commonly than isolated deep hypothermic circulatory arrest in neonatal and infant arch repair [1].

Second, the literature supports innominate artery cannulation as an effective route for establishing ACP and facilitating exposure during arch reconstruction [3, 4].

Third, the quality of ACP appears to matter greatly. Earlier low-flow strategies may have contributed to inconsistent neurologic benefit, whereas higher-flow, neuromonitoring-guided ACP has been associated with improved cerebral oxygen delivery and avoidance of postoperative white matter injury in some series [7].

Fourth, despite these advantages, there is still no universally accepted “best” ACP recipe. A recent review demonstrated wide ranges in target flow, temperature, and monitoring response across published neonatal studies, emphasizing that the field remains in a stage of refinement rather than full consensus [2].

7. Practical surgical pearls

7.1 Build the perfusion plan around the reconstruction

The cannulation strategy should not merely establish bypass; it should actively facilitate the repair. Innominate graft inflow is valuable because it improves exposure and simplifies transition to ACP.

7.2 Avoid overreliance on any single monitor

A normal right radial pressure does not prove adequate cerebral oxygen delivery, and an NIRS change must always be interpreted in context. Flow, hematocrit, temperature, carbon dioxide strategy, clamp position, and cannula orientation all matter.

7.3 Reconstruction time still matters

ACP improves cerebral protection, but it does not eliminate the physiologic cost of prolonged selective-flow states. Efficient arch reconstruction remains important for both neurologic and systemic reasons.

7.4 Neuroprotection extends beyond the operating room

Even when intraoperative perfusion management is excellent, long-term neurodevelopmental outcome in congenital heart disease is influenced by prenatal, perioperative, postoperative, genetic, and socioeconomic factors. Arch repair should therefore be viewed as one component of a broader neuroprotective continuum rather than as the sole determinant of later neurologic outcome [8].

8. Consolidated summary

Aortic arch advancement in neonates and infants is commonly performed through median sternotomy on CPB, with arterial inflow established through a graft to the innominate artery and venous drainage obtained through bicaval or single right atrial cannulation. During the reconstructive phase, selective antegrade cerebral perfusion under moderate hypothermia provides cerebral protection while allowing a controlled and accurate repair of the hypoplastic arch. Contemporary evidence supports ACP as a central neuroprotective strategy and supports the safety and utility of innominate artery cannulation, yet also shows ongoing variation in temperature targets, flow strategies, and monitoring protocols. For that reason, optimal results likely depend not on one isolated parameter, but on disciplined integration of cannulation, hypothermia, cerebral monitoring, and efficient reconstruction [1-8].

References

[1] Meyer DB, Jacobs JP, Hill K, Wallace AS, Bateson B, Jacobs ML. Variation in perfusion strategies for neonatal and infant aortic arch repair: contemporary practice in the STS Congenital Heart Surgery Database. World J Pediatr Congenit Heart Surg. 2016;7(5):638-644.

[2] Catalano MA, Toubat O, Nitsche LJ, Aronowitz DI, Beqaj H, Smood BF, Grasty M, Lynch JM, Gaynor JW, Mavroudis CD. Variation in techniques of selective antegrade cerebral perfusion in neonates undergoing aortic arch reconstruction: a comprehensive review. Ann Thorac Surg. 2025;120(3):591-602.

[3] Nasirov T, Mainwaring RD, Reddy VM, Sleasman J, Margetson T, Hanley FL. Innominate artery cannulation and antegrade cerebral perfusion for aortic arch reconstruction in infants and children. World J Pediatr Congenit Heart Surg. 2013;4(4):356-361.

[4] Fraser CD Jr, Andropoulos D. Principles of antegrade cerebral perfusion during arch reconstruction in newborns/infants. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu. 2008:61-68.

[5] Kornilov IA, Sinelnikov YS, Soinov IA, Ponomarev DN, Kshanovskaya MS, Krivoshchekov EV, Lomivorotov VV, Karaskov AM. Outcomes after aortic arch reconstruction for infants: deep hypothermic circulatory arrest versus moderate hypothermia with selective antegrade cerebral perfusion. Eur J Cardiothorac Surg. 2015;48(3):e45-e50.

[6] Hofer A, Haizinger B, Geiselseder G, Mair R, Rehak P, Gombotz H. Monitoring of selective antegrade cerebral perfusion using near infrared spectroscopy in neonatal aortic arch surgery. Eur J Anaesthesiol. 2005;22(4):293-298.

[7] Nelson DP, Andropoulos DB, Fraser CD Jr. Perioperative neuroprotective strategies. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu. 2008:49-56.

[8] Sood E, Newburger JW, Anixt JS, Cassidy AR, Jackson JL, Jonas RA, Lisanti AJ, Lopez KN, Peyvandi S, Marino BS, et al. Neurodevelopmental outcomes for individuals with congenital heart disease: updates in neuroprotection, risk-stratification, evaluation, and management: a scientific statement from the American Heart Association. Circulation. 2024;149(13):e997-e1022.