Selective antegrade cerebral perfusion (SACP) has become the standard cerebral protection strategy during modern aortic arch surgery, yet the optimal cerebral perfusion flow remains uncertain. This study by Piperata and colleagues sought to determine whether different indexed SACP flow ranges influence early clinical and neurological outcomes following complex aortic arch procedures.
The investigators retrospectively reviewed 492 adult patients who underwent aortic arch surgery at a high-volume Italian referral center between 2015 and 2024. All patients received bilateral SACP under moderate hypothermia using a standardized institutional protocol. Patients were divided into three groups according to indexed cerebral perfusion flow: low (<10 mL/kg/min), intermediate (10–15 mL/kg/min), and high (>15 mL/kg/min).
Most patients (80.3%) received perfusion within the recommended intermediate range of 10–15 mL/kg/min. Fourteen percent received lower flows, while only about 5% received higher flows. The investigators examined three primary clinical outcomes: 30-day mortality, permanent neurological dysfunction (stroke or persistent neurological injury), and transient neurological deficit, which included reversible postoperative neurological changes such as delirium or temporary motor dysfunction.
The principal finding was straightforward: no statistically significant relationship was identified between cerebral perfusion flow and any major clinical outcome. Whether perfusion was analyzed by predefined flow groups or as a continuous variable using spline regression, the risk of mortality, permanent neurological injury, and transient neurological complications remained similar across the observed range of flows.
The study also demonstrated how experienced surgical teams individualize cerebral perfusion in daily practice. Although institutional guidelines target 10–15 mL/kg/min, surgeons and perfusionists frequently adjust flow according to patient characteristics, body size, anatomy, cerebral oxygen monitoring, perfusion pressure, and intraoperative physiology. These individualized adjustments likely contributed to the favorable outcomes observed throughout the cohort.
Interestingly, patients receiving lower indexed flow tended to have larger body size, higher BMI, more emergency procedures, more acute type A dissections, and longer cardiopulmonary bypass times. Conversely, higher indexed flows were more common in redo operations and chronic aneurysm cases. Despite these important differences in case complexity, neurological outcomes remained comparable.
The authors emphasize that cerebral blood flow is far more complicated than simply delivering a weight-based pump flow. Cerebral autoregulation, metabolic demand, temperature, carbon dioxide levels, arterial pressure, vascular anatomy, collateral circulation, and cerebral oxygen consumption all influence actual cerebral perfusion. Consequently, indexed pump flow should be viewed as only one component of comprehensive cerebral protection.
The discussion places these findings within the broader literature. Previous investigations have reported conflicting results regarding optimal SACP flow, with recommended values varying substantially among institutions. Some studies suggest neurological injury increases below approximately 10 mL/kg/min, while others have safely used substantially lower flows. These discrepancies likely reflect differences in operative technique, monitoring strategies, temperature management, cannulation methods, and patient populations rather than a universal physiological threshold.
Several limitations should be considered when interpreting the findings. The study was retrospective and performed at a single institution using one standardized protocol. Most patients clustered within the intermediate flow range, limiting statistical power to evaluate extreme flow values. Additionally, advanced cerebral monitoring techniques such as routine transcranial Doppler and continuous electroencephalography were not systematically employed. Residual confounding is also possible because patients receiving low or high flows often differed substantially in surgical complexity.
Despite these limitations, the study contributes meaningful evidence to an area where high-quality randomized data remain lacking. Rather than supporting a rigid flow target, the results reinforce the importance of maintaining cerebral perfusion within generally accepted ranges while allowing experienced clinicians to tailor perfusion according to each patient’s physiology and intraoperative findings.
The authors conclude that individualized cerebral perfusion management may be more important than strict adherence to a single indexed flow threshold. They advocate future prospective randomized trials designed to establish more precise, patient-specific strategies for cerebral protection during aortic arch surgery. Until such evidence becomes available, maintaining SACP within the commonly recommended 10–15 mL/kg/min range while continuously adjusting therapy based on real-time monitoring appears to be a reasonable clinical approach.
