Utilizing Bifurcated Allogeneic Vein Grafts to Prevent Sinistral Portal Hypertension Following Pancreaticoduodenectomy

Academic Background

Pancreatic cancer is a highly malignant tumor with a poor prognosis, with a 5-year survival rate of less than 10%. The early invasive growth of pancreatic cancer often involves the portal vein system, particularly in tumors located in the pancreatic head or uncinate process, which frequently invade the confluence of the portal vein (PV), superior mesenteric vein (SMV), and splenic vein (SV). To achieve radical resection (R0 resection), surgeons typically perform pancreaticoduodenectomy (PD) combined with resection of the invaded portal vein system. However, this surgical approach may lead to sinistral portal hypertension (SPH), a localized form of portal hypertension caused by obstruction of splenic venous outflow, which can result in serious complications such as splenomegaly, thrombocytopenia, esophagogastric varices (EGV), and even gastrointestinal bleeding.

Currently, there is ongoing debate regarding how to manage the splenic vein during PD. Some surgeons argue that after splenic vein ligation, collateral circulation through the left gastric vein or other pathways can maintain splenic outflow, making splenic vein reconstruction unnecessary. However, increasing evidence suggests that patients may develop SPH within 6 months postoperatively if the splenic vein is ligated, significantly impacting their quality of life. Therefore, effectively preventing SPH has become a critical issue in pancreatic cancer surgery.

Source of the Paper

This paper was co-authored by Jing Wang, Shao-Cheng Lyu, Song-Ping Cui, and others, affiliated with the Department of Hepatobiliary and Pancreaticosplenic Surgery at Beijing Chaoyang Hospital and Massachusetts General Hospital, Harvard Medical School, among other institutions. The paper was published online on July 12, 2024, in the International Journal of Surgery, titled “Utilizing bifurcated allogeneic vein grafts: a novel approach for preventing sinistral portal hypertension following pancreaticoduodenectomy. A 10-year before and after study.”

Research Process and Results

Study Design

The study consisted of two parts: a retrospective study and a prospective study: 1. Retrospective Study: Clinical data from 66 patients who underwent PD combined with resection of the portal vein confluence at Beijing Chaoyang Hospital between January 2011 and December 2021 were collected. Based on whether the splenic vein was reconstructed, patients were divided into a reconstruction group (43 cases) and a ligation group (23 cases). 2. Prospective Study: From January 2021 to January 2023, 15 patients undergoing splenic vein reconstruction were prospectively enrolled and followed for at least 6 months.

Surgical Methods

• Reconstruction Group: Bifurcated allogeneic veins were used to reconstruct the portal vein, superior mesenteric vein, and splenic vein. The allogeneic veins were obtained from cardiac death donors, treated with antibiotics, and stored at low temperatures before use.
• Ligation Group: The splenic vein was directly ligated, and tubular allogeneic veins or end-to-end anastomosis were used to reconstruct the portal vein and superior mesenteric vein.

Key Results

1. Retrospective Study Results:

   • At 1, 3, and 6 months postoperatively, the reconstruction group showed better platelet counts, spleen volume, spleen volume ratio, and EGV grading compared to the ligation group (p < 0.05).
   • At 6 months postoperatively, the incidence of SPH in the ligation group was significantly higher than in the reconstruction group (36.4% vs. 8.1%).
   • Multivariate analysis revealed that intraoperative non-reconstruction of the splenic vein was the only independent risk factor for postoperative SPH (OR = 19.050).

2. Prospective Study Results:

   • Among the 15 patients who underwent splenic vein reconstruction, only 1 case (6.7%) developed EGV at 3 months postoperatively, possibly due to portal vein thrombosis causing splenic vein stenosis.
   • At 6 months postoperatively, platelet counts and spleen volume ratios remained stable, with an SPH incidence of 6.7%.

Data Analysis

The study used Kaplan-Meier curves and log-rank tests to compare SPH incidence between the two groups, with statistical analysis performed using SPSS 24.0 software. Measurement data were expressed as mean ± standard deviation or median (interquartile range), and categorical data were compared using χ² tests or Fisher’s exact probability method.

Conclusions and Significance

This study demonstrates that reconstructing the portal vein confluence using bifurcated allogeneic veins effectively prevents SPH following PD without increasing postoperative complications. This technique restores normal anatomical structure and hemodynamics, significantly reducing the incidence of SPH, improving platelet counts and spleen volume, and decreasing the risk of varices and gastrointestinal bleeding.

Research Highlights

1. Innovation: The first proposal to use bifurcated allogeneic veins for reconstructing the portal vein confluence, providing a novel solution for preventing SPH.
2. Clinical Value: Robust evidence from a 10-year retrospective study and prospective study supports the efficacy and safety of this technique.
3. Broad Applicability: This technique is suitable for patients with locally advanced pancreatic cancer, especially those with portal vein system invasion, expanding surgical indications.

Study Limitations

1. Single-Center Study: The small sample size may limit the generalizability of the results.
2. Technical Uniqueness: The bifurcated allogeneic vein reconstruction technique is currently only practiced at this center, requiring further promotion and multicenter validation.
3. Follow-Up Duration: For patients with longer survival, extended follow-up is needed to obtain more comprehensive clinical data.

Summary

This study provides an effective solution for preventing SPH following PD through the innovative use of bifurcated allogeneic vein reconstruction. This technique not only improves patients’ quality of life but also offers new insights into the surgical treatment of locally advanced pancreatic cancer. Future multicenter studies and long-term follow-up are needed to validate its broader applicability.