Acute aortic dissection (AAD) is among the most life-threatening emergencies in cardiovascular medicine, with the highest mortality rate of all cardiac surgical conditions [1]. Without immediate surgical intervention, mortality can exceed 90% [2]. Sun’s procedure—which entails replacement of the ascending aorta, total arch reconstruction, and distal stent-graft implantation—has become the preferred surgical approach for AAD owing to its favorable clinical outcomes [3, 4]. Nevertheless, because the procedure requires reconstruction of the cerebral vascular supply, postoperative neurological complications such as anxiety, stroke, and delirium continue to pose significant challenges [5]. Therefore, optimizing cerebral protection strategies has become a crucial research priority for improving perioperative organ preservation in aortic dissection repair. Current clinical practice utilizes various cerebral protection strategies, such as deep hypothermic circulatory arrest, retrograde cerebral perfusion via the superior vena cava, unilateral antegrade selective cerebral perfusion (uSACP), and bilateral antegrade selective cerebral perfusion (bSACP) [6]. Although our previous studies have confirmed the neuroprotective benefits of uSACP combined with moderate hypothermia in acute aortic dissection surgery, no standardized perfusion protocol has been widely established. Notably, significant inter-institutional variation remains in flow management strategies—with rates typically ranging from 5 to 15 mL/kg—and the assumed linear relationship between cerebral blood flow and patient body weight becomes unreliable beyond certain physiological thresholds. These observations highlight the importance of implementing goal-directed perfusion management to refine cerebral protection strategies [7, 8].

In aortic dissection surgery, cerebral oxygen saturation serves as an indicator of cerebral metabolic status. However, its clinical utility for guiding cerebral perfusion is limited by significant measurement variability, which hinders accurate quantification of optimal perfusion flow. Similarly, pressure-based flow selection strategies are constrained by the inherent inaccuracies of current pressure monitoring technologies, compromising their reliability in ensuring adequate neurological perfusion. In contrast, percentage-based flow management enables personalized perfusion strategies that may offer superior neuroprotection. Building upon this theoretical framework, the present study investigates percentage-flow guided unilateral antegrade selective cerebral perfusion (uSACP) in acute aortic dissection surgery, with the objective of establishing optimized parameters for neurological protection and functional outcomes.

Preserving neurological function is a critical priority in aortic arch reconstruction for acute dissection repair [9]. This complex surgical procedure differs fundamentally from routine cardiac operations due to its requirements for prolonged cardiopulmonary bypass, systemic hypothermia, deep hypothermic circulatory arrest of the lower body, and intricate arch reconstruction—all of which substantially disrupt cerebral metabolic homeostasis [10]. Contemporary cerebral protection strategies during arch reconstruction have yielded satisfactory clinical outcomes. Advances in understanding cerebral injury mechanisms and continuous refinement of surgical techniques have led to a consensus favoring progressively higher circulatory arrest temperatures, marking a transition from deep to moderate hypothermia. Substantial evidence indicates that unilateral selective cerebral perfusion combined with moderate hypothermia (24–28 °C) not only improves overall surgical efficacy but also reduces the incidence of stroke [11]. Our data show that cardiopulmonary bypass (CPB) times in both cohorts were only slightly longer than those observed in complex valve procedures, with an overall perioperative mortality rate of 4.6%—consistent with contemporary published outcomes [12]. These results affirm that technical advancements and optimized thermal management can effectively shorten CPB duration without compromising procedural safety. Nevertheless, current evidence remains largely based on single-center experiences, and the lack of standardized cerebral perfusion protocols continues to raise concerns regarding both safety and therapeutic efficacy.

In this study, we implemented goal-directed perfusion management to optimize tissue oxygenation during surgical intervention. Current evidence indicates that this perfusion strategy enhances neuroprotection in aortic dissection repair [13]. Nevertheless, significant controversy remains regarding optimal cerebral perfusion protocols. Conventional flow rate determination typically relies on patient weight and perfusion pressure parameters, supplemented by intraoperative cerebral oxygen saturation monitoring. This approach has several limitations: (1) cerebral oximetry readings exhibit considerable variability due to anesthetic depth, hypothermic conditions, and individual physiological differences; (2) the inherent latency of saturation monitoring impedes real-time flow precision; and (3) these limitations collectively increase the risk of both cerebral hyperperfusion and hypoperfusion, potentially exacerbating neurological injury.Physiological studies suggest that cerebral blood flow normally accounts for 15–20% of total cardiac output [14]. When normalized to brain tissue mass—approximately 2% of total body weight—percentage-based flow calculation may better reflect actual cerebral perfusion demands. Therefore, our study aimed to evaluate the neuroprotective efficacy of precision-adjusted percentage-flow cerebral perfusion, with the ultimate goal of establishing an optimized brain protection protocol for aortic arch surgery [15].

Guided by existing evidence on goal-directed perfusion in cardiac surgery, we maintained an intraoperative oxygen delivery (DO₂) target of 280 mL/m²$\cdot$min. Cerebral perfusion was initiated at 15% of the mean pre-deep hypothermic circulatory arrest (DHCA) flow rate and dynamically adjusted using near-infrared spectroscopy (NIRS) monitoring [16]. Although both groups showed comparable rates of major neurological complications such as stroke and seizures, the percentage-flow perfusion group demonstrated superior outcomes in several key areas: (1) a significantly lower incidence of transient neurological dysfunction; (2) improved cerebral oxygenation, reflected by higher NIRS values; and (3) reduced times to wakefulness and extubation. These results indicate that percentage-flow adjusted cerebral perfusion enables a more physiological flow distribution, leading to enhanced oxygen delivery, improved metabolic regulation, and optimized perfusion dynamics. Consequently, this approach offers strengthened neuroprotection—a conclusion that supports and extends previous research findings [17, 18].

This study further evaluated the expression levels of brain injury biomarkers under different perfusion strategies. The results demonstrated that postoperative serum levels of S100$\beta$ and NSE were significantly lower in the percentage-flow perfusion group compared to the conventional control group. These findings support the view that percentage-flow perfusion improves perfusion efficiency, helps maintain an optimal flow rate, enhances cerebral metabolic conditions, and reduces brain injury-related factors—consistent with conclusions from previous studies [19, 20, 21].

Building upon previous studies examining risk factors for neurological impairment after acute aortic dissection surgery, we analyzed data from the present patient cohort. The analysis identified age, unilateral cerebral perfusion time, and cardiopulmonary bypass (CPB) duration as significant contributors to postoperative neurological injury. Advanced age is associated with a progressive decline in physiological reserve, particularly affecting the cardiovascular and nervous systems. In elderly patients, preexisting cerebral arteriosclerosis may reduce baseline cerebral blood flow, increasing susceptibility to ischemic injury during surgery. Furthermore, the aging brain exhibits reduced tolerance to ischemia, rendering it more vulnerable to irreversible neuronal damage under conditions of inadequate perfusion. Unilateral cerebral perfusion—while useful for reducing overall cerebral perfusion pressure in selected scenarios—carries an inherent risk of hypoperfusion in the non-perfused hemisphere. Prolonged unilateral perfusion may exacerbate oxygen and nutrient deficiency in contralateral brain regions, potentially leading to neurological complications. Additionally, extended CPB time represents a major risk factor for neurological injury. Prolonged bypass can induce systemic hypothermia, acid-base imbalance, and coagulation disorders, all of which may adversely affect nervous system integrity. These findings align with previously published reports [22, 23, 24].

The implementation of percentage-flow-based cerebral perfusion management in acute aortic dissection surgery significantly enhances intraoperative cerebral protection. This strategy not only shortens the duration of postoperative mechanical ventilation and facilitates faster recovery from anesthesia but also effectively reduces the incidence of neurological complications. Furthermore, our results indicate that neurological injury is associated with patient age and the duration of cerebral perfusion during cardiopulmonary bypass. The developed predictive model demonstrates strong clinical utility, providing valuable guidance for optimizing cerebral perfusion strategies in this high-risk surgical population.

The data that support the findings of this study are available from the corresponding author, Wan, upon reasonable request.

YHY: Conceptualization, Methodology, Formal analysis, Investigation, Writing – original draft, Writing – review & editing. JCS: Data curation, Software, Validation, Visualization, Writing – review & editing. LW: Conception, Design, Resources, Supervision, Project administration, Funding acquisition. ZHW: Acquiring the patient data, Interpreting the imaging results. LLW: Investigation, Resources, Data curation, Writing – original draft. All authors contributed to editorial changes in the manuscript. All authors read and approved the final manuscript. All authors have participated sufficiently in the work and agreed to be accountable for all aspects of the work.

This study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by Nanjing First Hospital’s ethics committee (Ethics Approval No. KY20220805). All patients/participants or their families/legal guardians gave their written informed consent before they participated in the study.

This research received no external funding.

The authors declare no conflict of interest.