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World J Gastrointest Surg. Aug 27, 2026; 18(8): 120360
Published online Aug 27, 2026. doi: 10.4240/wjgs.120360
Sutureless portal vein reconstruction in porcine orthotopic liver transplantation using a microvascular coupler: A randomized study with artificial intelligence-assisted histopathology
Jun-Jie Li, Jian Yang, Jia-Ming Shang, Jiang Li, Chi-Yi Chen, Department of Liver Transplantation, Tianjin First Center Hospital, Tianjin 300192, China
Yan Xie, Wen-Tao Jiang, Department of Liver Transplantation, First Central Hospital of Tianjin Medical University, Tianjin 300380, China
Li-Na Liu, Zhong-Ying Zhang, Bing-Hui Pan, Hua Rong Ke Chuang Biotechnology (Tian Jin) CO. Ltd, Tianjin 300192, China
ORCID number: Jun-Jie Li (0000-0001-8318-3372); Jian Yang (0000-0001-9481-0407); Jiang Li (0000-0002-2368-9942); Wen-Tao Jiang (0000-0002-2064-6760).
Co-first authors: Jun-Jie Li and Jian Yang.
Co-corresponding authors: Yan Xie and Wen-Tao Jiang.
Author contributions: Li JJ and Yang J contributed equally to this article as co-first authors; Li JJ and Jiang WT conceived the study and performed critical revision of the manuscript for important intellectual content; Xie Y, Shang JM, Li J, Chen CY, Liu LN, Zhang ZY, and Pan BH collected the data; Yang J drafted the manuscript; Jiang WT and Xie Y contributed equally to this article as co-corresponding authors; and all authors thoroughly reviewed and endorsed the final manuscript.
AI contribution statement: We have written the response to reviewers from scratch, without any AI involvement whatsoever. It is assured that no AI software (DeepSeek, ChatGPT, etc.) was used in preparing this response.
Supported by Key Project of Scientific Research Plan of Tianjin Municipal Education Commission, No. 2024ZXZD010; Project of Tianjin Science and Technology Bureau Applied Basic Research, No. 23JCYBJC01800; and Beijing Hepatobiliary Sympathy Foundation Special Fund, No. iGandan-1082025-RGG009.
Institutional animal care and use committee statement: All procedures involving animals were reviewed and approved by the Institutional Animal Care and Use Committee of A-Jentec Institutional, approval No. ZH20231207P.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
ARRIVE guidelines statement: The authors have read the ARRIVE guidelines, and the manuscript was prepared and revised according to the ARRIVE guidelines.
Data sharing statement: The datasets generated and analyzed during the current study are available from the corresponding author upon reasonable request.
Corresponding author: Wen-Tao Jiang, Dean, Chief Physician, Full Professor, Department of Liver Transplantation, First Central Hospital of Tianjin Medical University, No. 2 Baoshan West Road, Xiqing District, Tianjin 300380, China. jiangwentao@nankai.edu.cn
Received: February 25, 2026
Revised: March 22, 2026
Accepted: May 25, 2026
Published online: August 27, 2026
Processing time: 173 Days and 21.5 Hours

Abstract
BACKGROUND

Portal vein reconstruction is a critical step in liver transplantation. Hand-sutured anastomosis is time-consuming and may predispose to malalignment, needle-hole bleeding, and stenosis. A sutureless, mechanically coupled anastomotic principle that minimizes mechanical trauma and foreign body reaction could improve healing.

AIM

To compare a microvascular anastomotic coupler (embodying the sutureless principle) with conventional hand-suturing for portal vein reconstruction in a translational porcine orthotopic liver transplantation model.

METHODS

Forty male pigs (weighing 60-66 kg) were randomized (1:1) to coupler or hand-sutured portal vein anastomosis. The primary endpoint was anastomosis time. Secondary endpoints included 12-week patency, portal venous velocity (Doppler), liver biochemistry, and detailed histopathological analysis of the anastomotic site. Histological evaluation was performed using an artificial intelligence-assisted workflow (ChatGPT-4.0 with vision) for pre-segmentation and provisional quantification, with all outputs independently reviewed and corrected by two blinded observers. Final analyses were conducted using the observer-verified values.

RESULTS

Coupler use halved anastomosis time (12.4 ± 2.2 minutes vs 24.5 ± 3.8 minutes, P < 0.001). Twelve-week patency was comparable (100% vs 95%, P = 1.000). Portal venous velocity remained stable and was consistently higher in the coupler group (immediate: 20.5 ± 3.1 cm/second vs 18.3 ± 2.6 cm/second, P = 0.020; 12-week: 22.9 ± 3.4 cm/second vs 20.8 ± 2.8 cm/second, P = 0.040). Liver function tests showed no significant between-group differences. Histology revealed significantly fewer inflammatory cells (macrophages, lymphocytes, and plasma cells) and a smaller necrotic area in the coupler group (e.g., macrophages: 5.3 ± 1.1 vs 8.6 ± 1.5 per high power field, P < 0.001), along with lower inflammation and tissue disorganization scores (both P < 0.001).

CONCLUSION

In a porcine liver transplantation model, the microvascular anastomotic coupler enables faster portal vein reconstruction while maintaining excellent patency, favorable hemodynamics, and superior histologic healing. These findings support its translational potential for clinical use.

Key Words: Microvascular anastomotic coupler; Sutureless anastomosis; Portal vein reconstruction; Porcine model; Liver transplantation; Artificial intelligence-assisted histopathology

Core Tip: This randomized porcine orthotopic liver transplantation study evaluates a microvascular anastomotic coupler for sutureless portal vein reconstruction. Compared with hand-sewn anastomosis, the coupler shortened anastomosis time by about 12 minutes while maintaining 12-week patency and portal hemodynamics. Quantitative, artificial intelligence-assisted (human-verified) histopathology demonstrated fewer inflammatory cells and smaller necrotic areas around the anastomosis, supporting a favorable local tissue response. These findings indicate that a simple, standardized coupler can reduce warm ischemia and technical variability without sacrificing vascular integrity, offering a practical pathway to streamline portal reconstruction in liver transplantation.



INTRODUCTION

Liver transplantation has become the standard treatment for patients with end-stage liver disease, significantly improving both survival and quality of life[1]. The procedure requires delicate surgical techniques to ensure correct connection of vessels and bile ducts. Among these, portal vein reconstruction is particularly critical because the portal vein supplies approximately 75% of hepatic blood flow, delivering nutrients and gut-derived toxins for processing[2].

Optimal vascular anastomotic healing is hindered by the mechanical trauma and chronic foreign-body response induced by conventional suturing[3]. Traditional portal vein reconstruction is typically performed with interrupted or continuous running sutures, sometimes using parachute, eversion/inversion techniques, or patch/vein-graft augmentation in complex cases. While effective in experienced hands, these approaches demand considerable skill and time, and may predispose to needle-hole bleeding, malalignment, and stenosis/thrombosis when tension is uneven[4-6]. Complications can lead to significant morbidity and may compromise graft survival[7].

Microvascular anastomotic couplers offer a potential solution by providing a standardized, sutureless method for vascular anastomosis[8,9]. These devices simplify the anastomosis process, reduce operative time, and minimize complications by ensuring precise luminal apposition without penetrating suture material[10,11]. Because portal vein anastomosis in transplantation occurs under ischemia–reperfusion and immunologic conditions that differ fundamentally from isolated vascular repair, evaluating couplers directly in an orthotopic allogeneic liver transplantation (OALT) model is essential for translational relevance.

In this study, we tested the hypothesis that a sutureless, mechanically coupled anastomotic principle—by ensuring precise apposition while eliminating penetrating foreign material—creates a superior healing microenvironment. We compared a microvascular anastomotic coupler against hand-sutured techniques for portal vein reconstruction in a randomized porcine OALT model, focusing on anastomotic time, patency, hemodynamics, and detailed artificial intelligence (AI)-assisted histopathology.

MATERIALS AND METHODS
Ethics approval

All animal experiments were approved by the A-Jentec Institutional Animal Care and Use Committee, approval No. ZH20231207P, and performed in accordance with relevant institutional and national guidelines. This study is reported in accordance with the ARRIVE guidelines.

Study design and animal model

A prospective, randomized, controlled study was conducted using a porcine OALT model. Forty male domestic pigs (age: 6 months; weight: 60-66 kg) were randomized into two groups (n = 20 each) using a computer-generated sequence concealed in sealed envelopes. Male pigs were used to reduce sex-related variability in vessel caliber and perioperative hormonal fluctuations, improving internal validity. Six-month-old pigs were selected because their portal vein caliber and wall thickness are comparable to adult humans, supporting translational relevance.

All surgeries were performed by a single experienced transplant surgeon (Li JJ) with over 15 years of experience in liver transplantation, including more than 500 orthotopic liver transplantations. Prior to the study, the surgeon had completed 10 training procedures with the coupler device on non-survival animals to overcome the learning curve. The same surgical team assisted in all operations to minimize variability.

Surgical procedure

Standard OALT was performed with the following sequential steps: Reconstruction of the suprahepatic and infrahepatic vena cava, portal vein anastomosis and reperfusion, hepatic artery reconstruction, and finally bile duct anastomosis. Anesthesia was induced with 5% isoflurane and maintained with 2% isoflurane. Preoperative care included fasting, intramuscular injection of 5 mg/kg cefazolin for infection control, and 0.1 mL/kg flunixin meglumine for analgesia.

After dissection and isolation, the portal vein was clamped and transected. In the coupler group, anastomosis was performed using a microvascular anastomotic coupler (KingSung Medical; NMPA registration No. 20233020825) according to the manufacturer’s instructions. The sequential steps of coupler application are illustrated in Figure 1. The appropriate coupler size was selected using a vascular gauge (Figure 2). In the control group, anastomosis was performed using continuous 6-0 polypropylene (Prolene) sutures.

Figure 1
Figure 1 Sequential steps of microvascular anastomotic coupler application. A: Align the transected portal vein ends and select the coupler size with a vascular gauge (outer diameter matched to vessel caliber); B: Open the coupler and expose the barbed pins; C: Evert each vein edge and seat the wall evenly onto the pins, ensuring full thickness capture without intimal folding; D: Repeat pinning on the contralateral stump with circumferential, evenly spaced engagement; E: Approximate the rings and lock using the mechanical rotation tool until the audible/visual stop is reached; F: Inspect for uniform apposition, absence of gaps/bleeding, and confirm lumen patency; G and H: Schematics showing pressure and tension distribution after closure, highlighting circumferential load sharing and anti-slippage by the barbed pins. P: Pressure; T: Tension; S: Sectional.
Figure 2
Figure 2 Device overview and surgical application for portal vein reconstruction. A: Schematic illustration of the microvascular anastomotic coupler (KingSung Medical; NMPA Reg. No. 20233020825) and its alignment mechanism; B: Vascular gauge for diameter measurement; C: The coupler device; D: Intraoperative preparation of the portal vein ends; E: Alignment and closure of the vessel ends using the rotation tool; F: Completed anastomosis showing a secure, uniform connection.

Anastomosis time was recorded from clamp application to release. Post-transplant immunosuppression was maintained with tacrolimus (trough 6-10 ng/mL in month 1), mycophenolate sodium, and a methylprednisolone taper. Intraoperative heparinization was guided by activated clotting time; postoperative low-molecular-weight heparin (anti-Xa 0.2-0.5 IU/mL) was initiated once hemostasis was secured (12-24 hours). Aspirin 75-100 mg daily was started on postoperative day 1 if bleeding risk allowed.

Outcome measures

The primary outcome was anastomosis time. Key secondary outcomes included 12-week patency, mean portal venous velocity (cm/second), peri-anastomotic complications (bleeding, stenosis, and thrombosis), liver function tests, and histology. Doppler ultrasonography was performed preoperatively, immediately post-operation, and at 1 week, 4 weeks, 8 weeks, and 12 weeks post-operation, with angle correction ≤ 60° to obtain time-averaged mean velocity. The incidence of complications was documented.

Bench validation of ring separation force

To verify ring-locking integrity and anti-slippage performance, we tested seven coupler sizes (4 mm, 6 mm, 8 mm, 12 mm, 16 mm, 20 mm, and 23 mm; n = 3 each). After full engagement per instructions for use, assemblies were mounted on a uniaxial tensile setup and loaded axially until decoupling; the peak load (N) at separation was recorded. The manufacturer’s technical requirement (N) was the priori acceptance threshold.

Histopathological analysis with AI assistance

At 12 weeks, portal vein samples encompassing the anastomosis were harvested, fixed, and sectioned for hematoxylin and eosin staining. Whole-slide images were scanned at 40 × magnification. A vision-capable large multimodal model (ChatGPT-4.0 with vision; OpenAI; accessed 2025) was used strictly as an assistive tool for pre-segmentation and provisional quantification of inflammatory cells (macrophages, lymphocytes, and plasma cells) and necrotic area percentage within standardized regions of interest. The AI outputs served only as an initial guide; the final data used for statistical analysis were exclusively the human verified values. This hybrid approach combines the efficiency of AI with the accuracy and biological insight of expert human judgment. Crucially, all AI-generated outputs were independently reviewed, corrected, and finalized by two blinded observers (Xie Y and Chen CY) according to pre-specified adjudication rules (detailed in Supplementary method of Supplementary material). AI-assisted histopathology has emerged as a powerful tool for objective and reproducible quantification[12,13]. The final dataset used for statistical analysis consisted entirely of these observer-verified values. In addition to cell counts, prespecified 4-point scales were used for semiquantitative assessment: Inflammation (0-3): 0 = none, 1 = scattered cells, 2 = multifocal clusters, and 3 = confluent dense infiltrates; tissue disorganization (0-3): 0 = normal, 1 = mild distortion without layer loss, 2 = partial layer loss/irregular thickening, and 3 = extensive disruption with loss of architecture.

Inter-observer agreement between the two reviewers was assessed using the intraclass correlation coefficient for continuous variables (cell counts and necrotic area) and Cohen’s kappa for categorical scores (inflammation and disorganization). Intraclass correlation coefficient values ranged from 0.91 to 0.96 for all cell types, and kappa values were 0.87 for inflammation score and 0.84 for disorganization score, indicating excellent agreement. Discrepancies were resolved by consensus with a third reviewer (Li JJ) when needed.

Statistical analysis

Sample size was calculated based on the primary endpoint (anastomosis time). Based on preliminary data, we estimated a mean anastomosis time of 24 minutes in the hand-sutured group and 12 minutes in the coupler group, with a common standard deviation of 3.5 minutes. To detect this difference with 80% power and a two-sided alpha of 0.05, 10 animals per group were required. To account for potential technical failures or perioperative mortality, we enrolled 20 animals per group. The sample size was not powered for secondary endpoints such as patency or complications, which are presented descriptively. Sample size calculation followed established guidelines for animal studies[14,15].

Continuous variables, presented as the mean ± SD, were compared using independent-samples t-tests (Welch’s t when variances were unequal). Categorical variables were compared using Fisher's exact test. Normality was assessed using the Shapiro-Wilk test. All primary and secondary continuous outcomes (anastomosis time, portal velocity, cell counts, necrotic area proportion, and biochemical parameters) were normally distributed (P > 0.05 for all). Therefore, parametric tests were used for comparisons. For variables that deviated from normality, the Mann-Whitney U test would have been applied; no such cases were identified in the final dataset. All tests were two-sided, with P < 0.05 considered statistically significant. Analyses were performed using SPSS 26.0 (IBM Corp.). Anastomosis time was the primary endpoint; all other outcomes were secondary/exploratory without multiplicity adjustment. P values are rounded to three decimals; an asterisk indicates P < 0.05.

RESULTS
Anastomosis time, patency, and operative outcomes

The use of the microvascular anastomotic coupler significantly reduced mean portal vein anastomosis time by approximately 50% compared to hand-suturing (12.4 ± 2.2 minutes vs 24.5 ± 3.8 minutes, P < 0.001). All anastomoses in the coupler group remained patent at 12 weeks (100%, 20/20), compared to 95% (19/20) in the hand-sutured group (P = 1.000); one case of stenosis was successfully treated by balloon angioplasty. Immediate postoperative anastomotic bleeding occurred in 10% (2/20) of hand-sutured cases and none in the coupler group (P = 0.487). Anastomosis time and patency outcomes are summarized in Table 1.

Table 1 Anastomosis time, patency rates, and blood flow, mean ± SD.
Parameter
Coupler group (n = 20)
Hand-sutured group (n = 20)
P value
Anastomosis time (minutes)12.4 ± 2.224.5 ± 3.8< 0.001a
Patency (%)100% (20/20)95% (19/20)1.000
Immediate bleeding (%)0% (0/20)10% (2/20)0.487
Stenosis (%)0% (0/20)5% (1/20)1.000
Preoperative velocity (cm/second)22.8 ± 5.523.1 ± 5.60.865
Immediate postoperative blood flow (cm/second)20.5 ± 3.118.3 ± 2.60.019a
Postoperative week 4 blood flow (cm/second)21.8 ± 3.319.7 ± 2.50.029a
Postoperative week 8 blood flow (cm/second)22.5 ± 3.320.6 ± 2.70.054
Postoperative week 12 blood flow (cm/second)22.9 ± 3.420.8 ± 2.80.039a
Hemodynamic assessment

Doppler ultrasound revealed significantly higher portal venous velocities in the coupler group at multiple time points (immediate: 20.5 ± 3.1 cm/second vs 18.3 ± 2.6 cm/second, P = 0.020; 4-week: 21.8 ± 3.3 cm/second vs 19.7 ± 2.5 cm/second, P = 0.029; 12-week: 22.9 ± 3.4 cm/second vs 20.8 ± 2.8 cm/second, P = 0.040). The difference at 8 weeks did not reach statistical significance (22.5 ± 3.3 cm/second vs 20.6 ± 2.7 cm/second, P = 0.054). Preoperative velocities were similar between groups (22.8 ± 5.5 cm/second vs 23.1 ± 5.6 cm/second, P = 0.865). Detailed hemodynamic data are presented in Table 1. Representative Doppler images and gross specimens are shown in Figure 3.

Figure 3
Figure 3 Doppler ultrasound and gross specimen evaluation. A: Doppler ultrasound and specimen evaluation of the coupler group. Columns 1-3: Doppler ultrasound images of portal vein velocity at pre-operation, 10 minutes post-operation, and 12 weeks post-operation for four representative cases. These images demonstrate stable velocity and patency. Column 4: Portal vein samples excised at 12 weeks, showing uniform healing and intact structures. Column 5: Liver specimens from the same animals, showing no visible ischemic damage; B: Doppler ultrasound and specimen evaluation of the hand-sutured group. Columns 1-3: Doppler ultrasound images at the same time points for four representative cases. Variable velocity and signs of stenosis or reduced patency are observed in some cases at 12 weeks. Column 4: Portal vein samples, showing occasional irregular healing and fibrosis. Column 5: Liver specimens, with some cases showing mild ischemic changes.
Liver function and biochemical markers

Liver function remained within normal physiological ranges for both groups throughout the 12-week follow-up, with no significant differences in alanine aminotransferase, aspartate aminotransferase, total bilirubin, alkaline phosphatase, gamma-glutamyl transferase, blood urea nitrogen, or creatinine levels (all P > 0.05). Albumin was slightly higher in the hand-sutured group (39.7 ± 2.5 g/L vs 38.1 ± 2.4 g/L, P = 0.046). Detailed results are shown in Table 2. Corresponding liver histology findings are shown in Figure 4.

Figure 4
Figure 4 Histological analysis of liver tissue in the coupler group/hand-sutured group. A: Histological analysis of liver tissue in the coupler group (hematoxylin and eosin staining). Representative images from five cases at 40 ×, 100 ×, and 400 ×. 40 ×/100 ×: Lobular architecture is preserved without significant inflammation, fibrosis, or necrosis. 400 ×: High magnification views show intact hepatocytes (yellow arrows), scattered lymphocytes (blue arrows), small necrotic areas (white arrows), and occasional polymorphonuclear cells (orange arrows), indicating minimal injury; B: Histological analysis of liver tissue in the hand-sutured group (hematoxylin and eosin staining). Representative images from five cases at 40 ×, 100 ×, and 400 ×. 40 ×/100 ×: Mild disorganization of lobular structure, focal necrosis, and inflammatory cell infiltration are seen in some cases. 400 ×: Intact hepatocytes (yellow arrows) and lymphocytes (blue arrows) are present, but overall inflammatory burden is higher.
Table 2 Laboratory examination at 12 weeks, mean ± SD.
Parameter
Coupler group (n = 20)
Hand-sutured group (n = 20)
P value
Hb (g/L)116.3 ± 8.4115.7 ± 9.10.829
ALT (U/L)35.2 ± 5.538.4 ± 6.90.113
AST (U/L)45.8 ± 6.348.3 ± 7.20.249
TBil (mg/dL)3.37 ± 0.23.51 ± 0.30.091
Albumin (g/L)38.1 ± 2.439.7 ± 2.5 0.046
ALP (U/L)107.4 ± 13.8116.2 ± 15.10.062
GGT (U/L)49.9 ± 8.554.9 ± 10.30.098
Creatinine (μmol/L)3.66 ± 0.714.75 ± 2.660.085
BUN (mmol/L)109.5 ± 18.9106.7 ± 15.20.609
Histopathological analysis of anastomotic healing

AI-assisted histopathology (with mandatory human verification) revealed pronounced differences between groups. The coupler group exhibited significantly lower counts of key inflammatory cells per high-power field: Macrophages (5.3 ± 1.1 vs 8.6 ± 1.5, P < 0.001), lymphocytes (4.1 ± 0.8 vs 5.8 ± 1.2, P < 0.001), and plasma cells (2.4 ± 0.4 vs 4.5 ± 1.0, P < 0.001). The proportion of necrotic area was also markedly lower in the coupler group (2.6% ± 0.5% vs 8.0% ± 1.7%, P < 0.001). Semiquantitative scores confirmed substantially reduced inflammation and tissue disorganization in the coupler group (both P < 0.001). Table 3 summarizes these findings, and representative images are shown in Figure 5.

Figure 5
Figure 5 Histological analysis of portal vein tissue in the coupler group/hand-sutured group. A: Histological analysis of portal vein tissue in the coupler group (hematoxylin and eosin staining). Representative images from five cases at 40 ×, 100 ×, and 400 ×. 40 ×/100 ×: The portal vein exhibits intact structure with minimal inflammation and no significant necrosis. Vessel walls are well preserved. 400 ×: Scattered macrophages (yellow arrows), lymphocytes (blue arrows), and rare plasma cells (orange arrows) are seen, with only small necrotic areas (white arrows); B: Histological analysis of portal vein tissue in the hand-sutured group (hematoxylin and eosin staining). Representative images from five cases at 40 ×, 100 ×, and 400 ×. 40 ×/100 ×: Structural disorganization, inflammatory cell infiltration, and focal necrosis are evident. Vessel walls show irregular thickening and fibrosis. 400 ×: Increased macrophages (yellow arrows), lymphocytes (blue arrows), plasma cells (orange arrows), and significant necrotic tissue (white arrows) are present, indicating higher inflammation and tissue injury.
Table 3 Histological analysis of portal vein anastomotic sites, mean ± SD.
Parameter
Coupler group (n = 20)
Hand-sutured group (n = 20)
P value
Macrophage count (HPF)5.3 ± 1.18.6 ± 1.5< 0.001
Lymphocyte count (HPF)4.1 ± 0.85.8 ± 1.2< 0.001
Plasma cell count (HPF)2.4 ± 0.44.5 ± 1.0< 0.001
Necrotic area proportion (%)2.6 ± 0.58.0 ± 1.7< 0.001
Inflammation score (0-3)0.8 ± 0.32.4 ± 0.6< 0.001
Tissue disorganization score (0-3)1.1 ± 0.62.7 ± 0.5< 0.001
Mechanical retention (bench testing)

All coupler sizes passed the predefined criterion: The lowest single reading for each model exceeded its requirement. Mean separation forces ranged from 56.6 N to 96.8 N, corresponding to 2.7 × to 16.6 × the requirement. The lowest single reading was 54.8 N (5 mm model, requirement 4 N), and the highest mean was 96.8 N (20 mm model, requirement 19 N). Detailed data are provided in Supplementary Table 1.

DISCUSSION

This randomized translational study demonstrates that a microvascular anastomotic coupler provides a feasible and efficient alternative to hand-sutured portal vein anastomosis in a porcine OALT model. The device achieved its primary objective of significantly reducing anastomosis time by approximately 50% while maintaining excellent mid-term patency. Beyond efficiency, it conferred significant histological benefits, including reduced peri-anastomotic inflammation and necrosis, indicating a more favorable healing response.

The superior outcomes are likely attributable to the coupler’s adherence to a biomechanical healing principle: Minimizing focal mechanical trauma and mitigating the chronic foreign-body reaction. On the one hand, the uniform circular force distribution and precise luminal apposition reduce focal endothelial shear stress and injury compared to intermittent suture points, explaining the improved hemodynamic profile[16]. On the other hand, the absence of permanent, penetrating foreign material circumvents the sustained foreign-body reaction that drives chronic inflammation and fibrosis[17]. The eversion-based coupling technique may also better preserve the vasa vasorum microcirculation, mitigating ischemic necrosis at the anastomotic rim, as evidenced by the dramatically lower necrotic area proportion.

The porcine model employed here provides a critical and predictive translational platform. The anatomical and physiological similarities of the porcine portal vein to humans lend direct relevance to our findings. The significant reduction in anastomosis time directly translates to a potential decrease in warm ischemia time, a crucial factor in clinical living-donor transplantation. Furthermore, the improved hemodynamic profile and reduced inflammatory response suggest a potentially lower risk of clinically relevant complications, such as early thrombosis and late stenosis.

Importantly, the rigorous AI-assisted histopathology workflow—with mandatory human verification—provides objective, quantitative evidence of the superior biological response, setting a new standard for translational device evaluation. While the coupler is a specific device, its design embodies a broader principle: The replacement of punctate, penetrating fixation with distributed, non-penetrating coupling, and the minimization of permanent, pro-inflammatory foreign material within the healing zone.

Limitations

This study has several limitations. The 12-week follow-up period, while adequate for assessing early healing, does not capture very late outcomes. The use of healthy animal vessels may not fully replicate the complexity of portal vein reconstruction in diseased human livers. The sample size was powered for the primary endpoint (time) and may be insufficient to detect small differences in patency or velocity. Only male pigs were included to reduce variability; future studies should include mixed-sex cohorts and larger samples to improve generalizability. Nevertheless, the consistency of the histological and hemodynamic benefits observed with the coupler strongly supports its translational potential.

CONCLUSION

In conclusion, this work provides compelling preclinical evidence that minimizing iatrogenic mechanical trauma and the foreign-body response through a sutureless, mechanically coupled principle creates a microenvironment conducive to superior vascular healing. The microvascular anastomotic coupler enables faster portal vein reconstruction while maintaining excellent patency, favorable hemodynamics, and superior histologic healing. These findings support its clinical translation and offer a rational foundation for innovating anastomotic techniques across surgical disciplines.

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Footnotes

Peer review: Externally peer reviewed.

Peer-review model: Single blind

Corresponding Author's Membership in Professional Societies: Chinese Society of Organ Transplantation, Standing Committee Member; Chinese College of Transplant Doctors, Chinese Medical Doctor Association, Committee Member; Tianjin Medical Association Organ Transplantation Branch, Chairperson; Organ Donation Group of the 7th Committee of Chinese Society of Organ Transplantation, Vice Chairperson; Hepatobiliary Surgery Committee of Chinese College of Surgeons, Standing Committee Member.

Specialty type: Gastroenterology and hepatology

Country of origin: China

Peer-review report’s classification

Scientific quality: Grade B

Novelty: Grade B

Creativity or innovation: Grade B

Scientific significance: Grade B

P-Reviewer: Au SCL, Chief Physician, Clinical Assistant Professor (Honorary), Principal Investigator, Research Fellow, China S-Editor: Bai Y L-Editor: Wang TQ P-Editor: Zhao YQ

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