Acute type A aortic dissection (ATAAD) is a rare but lethal cardiovascular disease, that accounts for approximately 60% of total aortic dissections (ADs) worldwide [1]. Patients who fail to receive prompt and comprehensive treatment in the early stage face a daunting mortality rate, estimated at 1% to 2% per hour [2], and a total mortality of 49% [3]. According to the international registry of acute aortic dissection (IRAD), surgical management can significantly decrease mortality from 23.7% to 4.4% at 48 hours, with a 3-year survival rate for discharged patients ranging from 69% to 90% [4]. Cardiac and aortic surgery remain the primary option and cornerstone of treatment for ATAAD patients [5]. However, patients who survive ATTAD surgery are commonly accompanied by long-term sequelae, including functional impairment and compromised quality of life. These are attributable to a spectrum of perioperative complications and diverse organ malperfusion [6, 7]. Furthermore, a retrospective study from China revealed the incidence of gastrointestinal (GI) dysfunction after ATAAD open surgery may reach 70%–80% if the occurrence of functional GI disorders, such as difficulty defecating, diarrhea, and abdominal distention, are considered [8, 9]. The occurrence of GI dysfunction has been shown to significantly increase the incidence of GI complications, prolong the intensive care unit (ICU) stay and duration of hospitalization after cardiac surgery [10, 11, 12]. Therefore, further improvement in the monitoring and management of GI function during the early postoperative phase is needed to reduce the incidence of GI dysfunction and facilitate the recovery of GI function in AD patients.

During the management of perioperative stage, the treatment of GI dysfunction in critically ill patients is mainly focused on early enteral nutrition, target-oriented fluid therapy, early transoral feeding, GI motility drugs, early physiotherapy and mobilization [13, 14, 15]. However, the clinical results of GI function recovery are still unsatisfactory, possibly due to the limitations of imposed by the early critical conditions of ATAAD patients.

Previous research has shown that transcutaneous electrical acupoint stimulation (TEAS) can improve postoperative GI dysfunction and reduce the duration of hospitalization [16]. Gastrointestinal electrical stimulation (GES) is another promising type of complementary therapy in GI dysfunction. In addition, GI pacing therapy is a type of electrotherapy based on the GI pacemaker theory. It generates a pacing current through the action of electrical pulses on the pacemaker area of the GI tract, thus regulating dynamic functions of the GI tract [17, 18]. Its therapeutic effects on the recovery of GI function include functional dyspepsia, abdominal distension, belching, anorexia, nausea, and gastroparesis, as well as intestinal dysfunction, irritable bowel syndrome, constipation, and other symptoms and diseases [19, 20].

Surface gastrointestinal electrical stimulation (SGES) is the combination of TEAS and GES. It may be a particularly promising option and clinical value in perioperative patients due to its non-invasiveness, low cost, and easy implementation compared with other invasive GI pacing therapies. Nevertheless, the application of SGES in patients after AD surgery is limited because of the pathophysiology of AD and dismal outcome of the AD population, and its clinical effects remain to be further clarified.

The principal objective of this study was to observe the efficacy of SGES in promoting GI function, reducing GI-related symptoms, shortening the duration of hospital stay, and improving the quality of life (QoL) of patients after AD surgery. This study is expected to provide evidence in favour of the application of SGES for perioperative patients, as well as a feasible pathway for the prevention and management of GI dysfunction in patients undergoing cardiac surgery.

The results of this study provide novel evidence regarding the effects of SGES based on ERP on GI function recovery after ATAAD open-heart surgery. This approach achieved the promotion of GI-2, that is, earlier postoperative transoral feeding and defecation, reduced GI-related symptom scores, and improved long-term GI-related QoL index.

Despite these encouraging findings, it is important to interpret the results in the context of the complex clinical landscape of ATAAD patients. GI recovery in this population is often complicated by severe physiological stress, surgical trauma, and heterogeneous postoperative trajectories. While SGES showed benefits in certain surrogate outcomes such as GI-2 and GSRS, no statistically significant effects were observed in more difficult to achieve endpoints such as constipation, diarrhea, IAP, or the duration of ICU/hospital stay. These results may reflect both the multifactorial nature of GI dysfunction and the possibility that TES offers modest, supportive effects rather than transformative clinical impact in this setting.

Recently, standardized enhanced perioperative management protocols have been introduced to facilitate GI recovery following major surgeries [35, 36]. However, patients undergoing cardiac surgery are prone to experience GI dysfunction, mainly because of reduced GI blood supply due to surgical trauma, stress reactions, and poor preoperative perfusion, all of which can negatively affect prognosis [37]. Although numerous RCTs have explored the clinical efficacy of various gastrointestinal electrical stimulation (GES) methods for general GI dysfunctions such as constipation and functional dyspepsia, their therapeutic potential and clinical applicability following open-heart surgery for ATAAD have yet to be investigated [38]. This gap in research may be attributed to the significant heterogeneity among ATAAD patients, the critical condition of these patients in the early postoperative stage, and the challenges associated with patient recruitment and long-term follow-up. The definition of GI dysfunction remains ambiguous, and there is currently no standardized approach for assessing and determining the extent of GI recovery [39]. Given that time to first flatus is considered an unreliable measurement, the current study employed the objective, composite time-based indicator GI-2 [40]. This was complemented by ultrasound assessment and GI symptom scores to evaluate multiple aspects of recovery and to enhance the sensitivity of assessment. We believe the development of such a comprehensive evaluation system for GI function holds promising clinical applicability and may improve the accuracy and consistency of postoperative assessments.

In this prospective RCT, SGES shortened the time to GI function recovery (GI-2) after open-heart surgery for ATAAD by 1.9 days compared to CG. This finding, is similar to the previous results for abdominal surgery [41]. Previous study showed that GES significantly improved GIQLI scores and symptom scores [42]. Consistent with this, in the present study SGES significantly reduced the total postoperative GI-related symptom scores during hospitalization as well as showing benefits in long-term GIQLI during follow-up. Although these improvements did not translate into significant differences in the incidence of constipation or diarrhea, AGIUS scores, length of ICU stay, or duration of hospitalization the study may have been underpowered to detect such effects.

No statistically significant differences in AGIUS results were found between IG and CG, although IG showed a improvement in intestinal motility as detected by ultrasound compared to CG. The relationship between intestinal ultrasound and gastrointestinal recovery is still unclear [43]. The primary outcome measures of interest in this study may not have been fully captured due to the complex pathophysiology and mechanism of postoperative GI dysfunction [44]. No previous study reported that GES can improve IAP. Similarly, there were no significant differences in the IAP measurement or IAP changes between IG and CG. Additionally, both the AGIUS and IAP measurements were relatively low in both groups, indicating that none of the enrolled patients had significant organic GI disorders. This aligns with the inclusion criteria for our study, which excluded patients with severe organic GI disease or high IAP in order to ensure baseline consistency.

The results of GSRS and GIQLI revealed that IG experienced significant positive effects in both short-term (assessed within one week of hospitalization) and long-term (assessed during the two weeks post-discharge) GI-related QoL. These improvements were observed for both early postoperative recovery and long-term recovery, thus highlighting the positive effects of SGES on GI-related QoL. The findings also indicated that the majority of patients undergoing ATAAD surgery had not fully regained 100% GI function by six months postoperatively. A previous study reported similar findings, with the health-related QoL of ATAAD patients showing a significant long-term decline after surgery [45]. This outcome may be due to multiple factors, including disease pathophysiology, surgical trauma, the complex effects of medication, reduced physical activity, and psychological or emotional influences [46].

The stimulation parameters and treatment area greatly influence the mechanism of action of GES [47]. The sites selected for electrical stimulation in this study were the projection of GI pacemaker on the body surface and two main acupoints. According to a previous systematic review and meta-analysis, ST36 and ST25 are the most commonly selected acupoint for transcutaneous electrical acupoint stimulation (TEAS), that can improve postoperative GI dysfunction [48]. Projection of the GI pacemaker covered by the electrode on the body surface by modulated medium frequency electrotherapy may have similar therapeutic effects, and is different to invasive GI pacemaker electrical stimulation [49]. Similar to interferential current (IFC), the current frequency (4 kHz plus 0.05 Hz–100 Hz) selected in this study is better tolerated and well suited to penetrate deeper tissues for GI dysfunction [50, 51]. Moreover, although SGES incorporates acupoint stimulation and noninvasive GI pacing, the precise biological mechanisms underlying its effects remain incompletely understood. Hypotheses include neuromodulation of autonomic control, enhancement of GI pacemaker activity, and reduction of inflammation. However, direct mechanistic evidence in post-cardiac surgery patients is still lacking.

Of note, the adoption of TES in clinical practice remains limited, especially in cardiac surgery patients. This is due to concerns surrounding feasibility, cost-effectiveness, and the need for standardization. Our study does not seek to recommend routine TES use, but rather seeks to stimulate further inquiry. We consider this work to be hypothesis-generating and exploratory, with the goal of opening new avenues for multidisciplinary interventions that target GI recovery in high-risk surgical patients.

This study has several limitations. It was conducted in a medical center with a strict ERP, which may limit the generalizability of the results to other settings. Due to the nature of the intervention, it was deemed impractical to implement blinding for both the participants and assessors. However, the blinding principles were strictly followed for data assessors, with independent arrangements for the interventionists, assessors, and data handlers. Data analysis was also conducted under blinded conditions with respect to group allocation. The absence of a placebo-controlled group in this trial means that the placebo effect could not be excluded, which may impact the interpretation of treatment outcomes. Additionally, challenges with patient recruitment resulted in a smaller sample size and a higher than expected dropout rate during follow-up. These issues were primarily due to the geographical distribution of some patients in remote areas of China. Another noticeable consideration is that while an attempted was made to address the significant heterogeneity among TAAD patients by ensuring consistency in baseline surgical data (e.g., duration of surgery, extracorporeal circulation time, and anesthesia time), the potential influence of variations in surgical techniques on the study outcomes remains uncertain. Furthermore, the physiological basis for SGES remains speculative, with no direct biomarkers or electrophysiological endpoints included. Finally, this study reflects an early-stage clinical trial, and we caution against interpreting the results as conclusive.

If possible, future research should focus on a specific type of surgical approach to minimize variability and improve the precision of results. It may also be worthwhile to consider whether ultrasound and IAP measurement should be used as routine monitoring tools for GI dysfunction after ATAAD open heart surgery. Future large-scale clinical studies are expected to further reveal the optimal therapeutic parameters and mechanisms of SGES therapy. We recommend further multicenter trials with a larger sample size, standardized stimulation protocols, and embedded mechanistic assessments to further evaluate TES. SGES may represent a feasible, non-invasive adjunctive strategy, but its role must be more clearly defined through rigorously designed studies.

This study provides preliminary evidence supporting the clinical benefits of SGES in improving GI function and QoL, as well as the reduction of GI symptoms scores after open heart surgery in ATAAD patients. Further large-scale studies are warranted to confirm these findings and to explore the broader implications and mechanisms of SGES in postoperative recovery strategies for cardiac surgery patients.

The datasets used and analyzed during the current study are available from the corresponding author on reasonable request.

WD and ZRXL designed the research study. WD drafted the initial manuscript of this protocol. ZL, XZ and MC revised the manuscript. WD and ZRXL were involved in the intervention. JS, ZL and WH collected and managed the trial data. XZ and WH provided methodological and statistical expertise. PMY supervised the project from conception through publication, provided critical revisions, and served as the corresponding author. All authors contributed to conception and critical revisions, and approved the final version of the manuscript. All authors meet the ICMJE criteria for authorship, have participated sufficiently in the work to take public responsibility for appropriate portions of the content, and agree to be accountable for all aspects of the work.

This study was carried out in accordance with the guidelines of the Declaration of Helsinki and approved by the Ethical Committee of West China Hospital (No.20230112). Written informed consent was obtained before discharge.

This study was supported by the Major Project of the Science and Technology Department in Sichuan province China (grant number 2024YFFK0138).

The authors declare no conflict of interest.