This study is a single-center retrospective cohort analysis, consecutively collected 58 patients with acute DeBakey Type I aortic dissection who underwent emergency surgery in the Department of Cardiovascular Surgery of our hospital from August 2023 to October 2024. All data were extracted from the electronic medical record system and surgical records. All patients received ascending aorta replacement, total aortic arch replacement, and descending aorta stent grafting (Sun’s procedure). Patients were divided into two groups based on whether the LSA was dissected during surgery: the experimental group (n = 28, using non-dissection LSA combined with single-branch intraoperative stent grafting technique) and the control group (n = 30, traditional LSA dissection technique). The study was approved by the Ethics Committee of our hospital (Approval number 2025050). Due to the retrospective nature of the analysis, patient informed consent was waived, and all data were anonymized.

Inclusion Criteria: ① Patients diagnosed with acute Stanford Type A aortic dissection (symptom onset to surgery time 72 hours), DeBakey Type I. ② Undergoing Sun’s procedure for the first time. ③ Aged between 18 and 75 years. ④ Preoperative CTA confirmed that the dissection involved the ascending aorta, aortic arch, and the entire descending aorta. Exclusion Criteria: ① DeBakey Type II or III dissection. ② Presence of thoracic aortic aneurysm, Marfan syndrome, or previous aortic surgery. ③ Severe organ failure preoperatively (such as cardiogenic shock, renal failure requiring dialysis) or malignancy.

In the control group, the surgical procedure was conducted as follows: (1) After satisfactory anesthesia, the patient was placed in the supine position followed by routine disinfection and draping; a femoral artery incision and median sternotomy were performed to expose the vessels and establish cardiopulmonary bypass (CPB) with systemic heparinization (3 mg/kg, ACT $>$480 s); (2) Under cooling and left atrial venting, the distal ascending aorta was cross-clamped, ventricular fibrillation was induced, and a transverse aortotomy was made for HTK cardioplegia delivery; the diseased aorta was resected and the aortic root was managed with valve repair, Bentall, or Wheat procedure as appropriate, followed by proximal graft anastomosis with 4-0 Prolene suture; (3) Under bilateral cerebral perfusion initiated at nasopharyngeal temperature of 30 °C, lower body circulatory arrest was implemented, the aortic arch was opened distally to the left subclavian artery, and the distal anastomosis was performed—specifically, the anastomosis sequence was: left common carotid artery, aortic proximal end, left subclavian artery, and brachiocephalic artery; (4) Perfusion to the lower body was restored via the graft, cardiac reperfusion was achieved, rewarming was initiated, and the heart was defibrillated if necessary; arch vessel anastomoses were completed and the patient was weaned from CPB after stabilization. The experimental group adopted the same procedures except for the modified distal stent graft deployment, wherein the arch incision was made between the left common carotid and subclavian arteries, and under direct vision, the stent was deployed stepwise: the main body was first placed in the descending aortic true lumen to seal the entry tear, followed by precise branch stent release into the left subclavian artery, avoiding misalignment or twisting—all other technical aspects remained consistent, enabling a rigorous comparative assessment. Fig. 1 provides a schematic representation of the entire surgical or research process.

Fig. 1.

Application of non-mobilized left subclavian artery (LSA) with single-branched intraoperative stent graft technique in acute DeBakey type I aortic dissection surgery versus classical Sun’s procedure. (A1) Intraoperative mobilization of the brachiocephalic trunk and left common carotid artery. (A2) Intraoperative deployment of the single-branched stent graft. (A3) Schematic demonstrating aortic arch replacement with a four-branched artificial graft and concurrent descending aortic single-branched stent graft implantation for vascular remodeling. (B1, B2) Classical Sun’s procedure schematic, illustrating aortic arch replacement with a four-branched artificial graft and concurrent elephant trunk stent implantation in the descending aorta for vascular remodeling. LSA, left subclavian artery.

Statistical analysis was performed using SPSS 26.0.0.0. (IBM-SPSS Statistics, Chicago, IL, USA). Normally distributed continuous variables were expressed as mean $\pm$ standard deviation ($\overline{x}$ $\pm$ S) and compared between groups using the independent samples t-test. Non-normally distributed continuous variables were described as median (interquartile range) [M (P25, P75)] and analyzed with the Mann-Whitney U test. Categorical variables were presented as percentages (%) and compared between groups using Pearson’s chi-square test, continuity correction chi-square test, or Fisher’s exact test, as appropriate.

The two groups were comparable in terms of preoperative baseline characteristics. As shown in Table 1, there were no statistically significant differences between the experimental group (n = 28) and the control group (n = 30) in terms of age (54.93 $\pm$ 1.865 years vs. 54.13 $\pm$ 2.011 years, p = 0.774), hypertension (89.29% vs. 86.67%, p = 1.000), diabetes (3.57% vs. 6.67%, p = 1.000), and coronary heart disease (14.29% vs. 16.67%, p = 1.000) (all p $>$ 0.05). The proportion of smoking history was significantly lower in the experimental group than in the control group (42.86% vs. 66.67%, p = 0.068), but it did not reach the statistical significance threshold (p 0.05). Other variables (such as renal insufficiency, hyperlipidemia, chronic obstructive pulmonary disease, etc.) also showed no statistically significant differences between the two groups (Table 1).

The experimental group demonstrated significantly better intraoperative time efficiency compared to the control group. The total operative time was significantly shorter in the experimental group (256.21 $\pm$ 53.08 minutes vs. 298.97 $\pm$ 51.09 minutes, t = –3.125, p = 0.003). Additionally, the experimental group had significantly shorter aortic cross-clamp time (median 37.00 minutes vs. 46.50 minutes, Z = –2.296, p = 0.022) but a longer circulatory arrest time (median 10.00 minutes vs. 8.50 minutes, Z = –3.476, p = 0.001) compared to the control group. However, there were no statistically significant differences between the two groups in terms of cardiopulmonary bypass time (p = 0.056) and heparinization time (p = 0.950) (Table 2).

The experimental group showed better performance in postoperative recovery and complication control. The drainage volume on the first postoperative d ay was significantly lower in the experimental group (median 843.00 mL vs. 1099.00 mL, Z = –2.303, p = 0.021), and the total amount of red blood cell transfusion was also lower (median 6.00 U vs. 7.00 U, Z = –2.085, p = 0.037). The experimental group had significantly shorter tracheal intubation time (median 87.50 hours vs. 140.00 hours, Z = –2.723, p = 0.006), ICU stay duration (median 159.50 minutes vs. 257.00 minutes, Z = –3.649, p 0.001), and postoperative hospital stay (median 14.00 days vs. 21.00 days, Z = –3.412, p = 0.001) showed no statistically significant difference in mortality, re-thoracotomy rate, hoarseness, or chylothorax (p $>$ 0.05); please see Table 3 for detailed causes of mortality among deceased patients in both groups. No strokes occurred postoperatively in either group.

This study systematically validated the significant advantages of the non-dissection LSA combined with single-branch stent grafting technique in the surgical treatment of acute DeBakey Type I aortic dissection. The total operative time in the experimental group was reduced by approximately 43 minutes compared to the traditional technique (p = 0.003), primarily due to the simplification of the dissection of the posterior wall of the aortic arch. In the traditional technique, dissection of the LSA requires extensive separation of the posterior wall of the aortic arch to expose the recurrent laryngeal nerve and the course of the thoracic duct, which is not only time-consuming but also prone to nerve injury or lymphatic rupture due to traction [21]. In contrast, the single-branch stent grafting technique achieves precise anchoring of the stent branch to the LSA orifice, directly reconstructing blood flow without the need for LSA dissection and anastomosis [22]. Additionally, the experimental group had a 23% reduction in postoperative drainage volume (p = 0.021) and a 14% decrease in red blood cell transfusion (p = 0.037), which may be related to the reduced intraoperative injury to the lymphatic system [23]. Injury to the thoracic duct in the traditional technique can lead to chyle leakage, while no chylothorax occurred in the experimental group, further confirming the protective effect of the non-dissection technique on lymphatic structures [24]. It is noteworthy that although the circulatory arrest time was slightly longer in the experimental group (10.0 minutes vs. 8.5 minutes), the aortic cross-clamp time was significantly shorter (37.0 minutes vs. 46.5 minutes, p = 0.022). The slightly prolonged circulatory arrest time in the experimental group (10.0 minutes vs. 8.5 minutes) reflects the deliberate intraoperative verification of true lumen guidewire positioning and precise deployment of the branched stent graft under direct vision; however, this necessary technical step crucially ensured accurate LSA branch anchoring without increasing neurological complications or compromising overall surgical efficiency gains. This suggests that the technique optimizes the aortic arch operation process, reducing the organ ischemic burden during deep hypothermic circulatory arrest (DHCA), which may have potential value in improving neurological prognosis [25].

Chylothorax and hoarseness are common complications associated with traditional Sun’s procedure. In this study, the incidence of these complications was 0% in the experimental group, while the control group had incidences of 6.67% and 10%. This can be largely attributed to the unique anatomical structure of the LSA [26, 27]: the recurrent laryngeal nerve loops beneath the aortic arch and is susceptible to thermal or traction injury during traditional LSA dissection. Meanwhile, the thoracic duct, which drains into the venous system between the left common carotid artery and the LSA, can be inadvertently severed during surgery, leading to chylothorax. The single-branch stent grafting technique circumvents these risks by avoiding dissection of the posterior aortic arch wall [28]. Previous studies have reported postoperative hoarseness rates of 5%–15% with traditional methods. The zero incidence in our experimental group significantly outperforms these figures, suggesting that this technique could be a great strategy for reducing nerve injury. Moreover, the experimental group experienced a 38% reduction in ICU stay duration (p 0.001) and a 33% decrease in postoperative hospital stay (p = 0.001), which may be related to the lower incidence of complications and reduced surgical trauma.

The application of single-branch stent grafting not only simplifies surgical procedures but also enhances the stability of the distal anastomosis with its radial support force. In traditional techniques, the anastomosis between the descending aorta stent graft and the artificial vessel relies on suture techniques, which are prone to endoleak or anastomotic tear due to tissue fragility. In contrast, the branched stent graft used in the experimental group, by anchoring the true lumen, can evenly distribute the hemodynamic shear forces, thereby reducing the risk of late endoleak [29]. Moreover, preserving the anatomical continuity of the LSA helps maintain blood flow perfusion to the left upper limb and the vertebrobasilar artery, potentially reducing the incidence of postoperative spinal cord ischemia [30]. However, it is necessary to be vigilant about the potential risks of branched stent grafting. First, the true lumen of an acute dissection is often compressed and narrowed, and any deviation in stent deployment may result in incomplete coverage of important branches. Second, the mobility of the distal intimal flap of the dissection may affect the stent apposition. In this study, the rethoracotomy rate in the experimental group was comparable to that in the control group (10.71% vs. 10.00%), indicating the need for further optimization of stent deployment techniques, such as combining intraoperative ultrasound or angiography to confirm the position of the true lumen guidewire.

Although no statistical difference was found in mortality rates between the experimental and control groups (28.57% vs. 10.71%, p = 0.071), the causes of death detailed in Table 3 reveal that among the 8 deaths in the experimental group, 5 were due to coagulation disorders, 2 resulted from unrecoverable malignant arrhythmia (ventricular fibrillation), and 1 was caused by multiple organ failure; the 3 deaths in the control group were attributed to multiple organ failure, coagulation disorders, and acute respiratory distress syndrome (1 case each). The primary causes of mortality were associated with the critical nature of acute Debakey type I aortic dissection itself, preoperative malperfusion of multiple organs, and postoperative coagulation dysfunction, rather than being directly related to the technical approach for managing the left subclavian artery. The higher proportion of coagulation disorders in the experimental group may indicate a worse preoperative coagulation status or a more severe surgical stress response in these patients, though the difference was not significant likely due to the limited sample size; cases of ARDS and multiple organ failure in the control group might be related to intraoperative ischemia-reperfusion injury and postoperative inflammatory responses. These results suggest that the two techniques did not significantly differ in their impact on ultimate patient survival, which was primarily determined by the severity of the primary disease and the patients’ systemic condition; further studies with larger samples are needed to better identify high-risk factors and clarify their relationship with technical selection.

The current study has the following limitations: First, the retrospective design makes it difficult to completely eliminate selection bias. Although the baseline data are well matched, the lower proportion of smoking history in the experimental group (42.86% vs. 71.43%) may affect the interpretation of postoperative recovery indicators. Second, the small sample size (n = 58) may reduce statistical power, especially in the analysis of hard endpoints such as mortality (28.57% vs. 10.71%, p = 0.142), which requires cautious interpretation. Third, the lack of long-term follow-up data means that the durability of the branch stent and long-term complications (such as stent migration or new entry tear) cannot be assessed. In the future, multicenter randomized controlled trials should be conducted, combined with intraoperative imaging navigation technology, to further verify the safety of this surgical procedure. In addition, the application of the new type of four-branch stent may achieve anatomical reconstruction of the entire aortic arch vessels, but its feasibility in acute dissection still needs to be explored [31].