Safety and efficacy of cryopreserved homologous veins for venous reconstruction in pancreatoduodenectomy

Thrombosis and anticoagulation after portal vein reconstruction during pancreatic surgery: a systematic review

BACKGROUND

Portal vein (PV) resection and reconstruction, which includes the resection and reconstruction of the PV and superior mesenteric vein, enable surgical removal of borderline resectable and locally advanced pancreatic cancer. Thrombosis of the reconstructed PV represents a major cause of early postoperative and long-term morbidity and mortality. No universally accepted standard for anticoagulation exists. This study aimed to assess early and late thrombosis rates after PV reconstruction with special regard to the type of PV reconstruction and anticoagulation regimen and to comprehensively assess thrombotic events and their clinical effect in patients receiving pancreatic surgery with venous resection and reconstruction.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. Studies reporting on PV resection and reconstruction providing data on thrombosis rates were included. The following parameters were assessed: study type, year of publication, number of patients, type/number of PV reconstruction, follow-up period, postoperative mortality, thrombosis rate of the reconstructed PV axis, intraoperative blood loss, and anticoagulation.

RESULTS

A total of 23 studies with 2751 patients were included in the final analysis. Of note, 670 patients received tangential resection of the PV with venorrhaphy or patch repair, 1505 patients had segmental resection with end-to-end reconstruction, and 576 patients received reconstruction with an interposition graft/conduit. The pooled overall thrombosis rate was 15%. Reconstruction of tangential defects with either venorrhaphy or patch repair and end-to-end repair of segmental defects resulted in a thrombosis rate of 12%. Subgroup analysis according to the type of graft reconstruction revealed the highest occlusion rates of 55% in patients with allogeneic grafts, followed by up to 27% in patients with synthetic PV conduits. Autologous conduits had a thrombosis rate of 10%. Early thrombotic events were detected in 5% of patients after venorrhaphy/patch reconstruction and end-to-end reconstruction. Early events were most common in the allogeneic graft subgroup (22%), followed by synthetic conduits (15%). There were fewer early events in the autologous graft group (7%). Early PV thrombosis was associated with relevant mortality of up to 26%. Anticoagulation regimens varied between studies.

CONCLUSION

The overall thrombosis rate after PV resection is low. However, among the different reconstruction techniques, allogeneic interposition grafts/conduits had the highest thrombosis rates among the different types of reconstruction after PV resection. No specific anticoagulation strategy can be considered beneficial based on the existing literature.

Three-Dimensional Bio-Printed Tubular Tissue Using Dermal Fibroblast Cells as a New Tissue-Engineered Vascular Graft for Venous Replacement

The current study was a preliminary evaluation of the feasibility and biologic features of three-dimensionally bio-printed tissue-engineered (3D bio-printed) vascular grafts comprising dermal fibroblast spheroids for venous replacement in rats and swine. The scaffold-free tubular tissue was made by the 3D bio-printer with normal human dermal fibroblasts. The tubular tissues were implanted into the infrarenal inferior vena cava of 4 male F344-rnu/rnu athymic nude rats and the short-term patency and histologic features were analyzed. A larger 3D bio-printed swine dermal fibroblast-derived prototype of tubular tissue was implanted into the right jugular vein of a swine and patency was evaluated at 4 weeks. The short-term patency rate was 100%. Immunohistochemistry analysis showed von Willebrand factor positivity on day 2, with more limited positivity observed on the luminal surface on day 5. Although the cross-sectional area of the wall differed significantly between preimplantation and days 2 and 5, suggesting swelling of the tubular tissue wall (both p < 0.01), the luminal diameter of the tubular tissues was not significantly altered during this period. The 3D bio-printed scaffold-free tubular tissues using human dermal or swine fibroblast spheroids may produce better tissue-engineered vascular grafts for venous replacement in rats or swine.

Resection and reconstruction of the largest abdominal vein system (the inferior vena cava, hepatic, and portal vein): a narrative review

BACKGROUND AND OBJECTIVE

As tumors invade major abdominal veins, surgical procedures are transformed from simple and basic to complicated and challenging. In this narrative review, we focus on what is currently known and not known regarding the technical aspects of major abdominal venous resection and its reconstruction, patency, and oncologic benefit in a cross-cutting perspective.

METHODS

A systematic literature search was performed in PubMed and Semantic Scholar from inception up to October 18, 2023. We reviewed 106 papers by title, abstract, and full text regarding resection or reconstruction of the inferior vena cava, hepatic vein confluence, portal vein (PV), and middle hepatic vein (MHV) tributaries in living donor liver transplantation (LDLT) in a cross-cutting perspective.

KEY CONTENT AND FINDINGS

The oncologic benefit of aggressive hepatic vein resection with suitable reconstruction against adenocarcinoma remains unclear, and further studies are required to clarify this point. A superior mesenteric/PV resection is now a universal, indispensable, and effective procedure for pancreatic ductal adenocarcinoma. Although many case series using tailor-made autologous venous grafts have been reported, not only size mismatch but also additional surgical incisions and a longer operation time remain obstacles for venous reconstruction. The use of autologous alternative tissue remains only an alternative procedure because the patency rate of customized tubular conduit type to interpose or replace the resected vein is not known. Unlike arterial replacement, venous replacement using synthetic vascular grafts is still rarely reported and there are several inherent limitations except for reconstruction of tributaries of MHV in LDLT.

CONCLUSIONS

Various approaches to abdominal vein resection and replacement or reconstruction are technically feasible with satisfactory results. Synthetic vascular grafts may be appropriate but have a certain rate of complications.

Cryopreserved allografts versus end-to-end anastomosis for the reconstruction of a segment-resected portomesenteric vein during advanced pancreatic cancer surgery

BACKGROUND

Porto-mesenteric vein (PMV) infiltration of pancreatic cancer is classified as borderline resectable cancer. For en-bloc resectability, the probability of PMV resection and reconstruction is the most decisive factor. The purpose of this study was to compare and analyze PMV resection and reconstruction during pancreatic cancer surgery using end-to-end anastomosis (EA) and a cryopreserved allograft (AG) and to verify the effectiveness of reconstruction using an AG.

METHODS

Between May 2012 and June 2021, 84 patients (65 underwent EA, and 19 received AG reconstruction) underwent pancreatic cancer surgery with PMV reconstruction. An AG is a cadaveric graft with a diameter of 8-12 mm and is obtained from a liver transplant donor. Patency after reconstruction, disease recurrence, overall survival, and perioperative factors were assessed.

RESULTS

The median age was higher in EA patients (p = .022) and neoadjuvant therapy (p = .02) was more in AG patients. Upon histopathological examination, the R0 resection margin did not show a significant difference by reconstruction method. During a 36-month survival analysis, primary patency was significantly superior in EA patients (p = .004), and there was no significant difference in recurrence-free survival (p = .628) or overall survival (p = .638) rates.

CONCLUSION

Compared with EA, AG reconstruction after PMV resection during pancreatic cancer surgery showed a lower primary patency, but there was no difference in recurrence-free or overall survival rates. Therefore, the use of AG can be a viable option for borderline resectable pancreatic cancer surgery if the patient is properly followed-up postoperatively.

Peritoneal patch in vascular reconstruction during pancreaticoduodenectomy for pancreatic cancer: a single Centre experience

BACKGROUND

Concomitant venous resection during pancreaticoduodenectomy (PD) for pancreatic adenocarcinoma with mesenterico-portal vein involvement is increasingly performed to achieve oncological resection. This study aims to report a single centre experience in peritoneal patch (PP) as autologous graft for vascular reconstruction (VR) during PD.

METHODS

A retrospective analysis of all patients who underwent PD + VR with PP between December 2019 and September 2020 was performed, using a prospective collected database. Postoperative outcome and pathological margins were evaluated. Venous patency was assessed by computed tomography at day 7 and week 12 post surgery.

RESULTS

Fifteen patients underwent PD + VR with PP reconstruction for pancreatic cancer, including one total pancreatectomy. VR consisted of lateral (n = 14) or tubular (n = 1) patch. The median PP length was 30 mm [26.3-33.8] and venous clamping time 30 min [27.5-39.0]. Computed tomography showed a patent VR in 93.3% and 53.3% after 7 days and 12 weeks, respectively; venous patency loss was always asymptomatic. The only postoperative VR-related complication was one mesenteric venous thrombosis. Five other patients experienced VR-unrelated complications: septic shock (n = 3), biliary fistula (n = 1) and post-traumatic subdural hematoma (n = 1). Mortality was nihil. At pathology, R0 resection (≥1 mm) was observed in 40.0% (6/15), venous margin was free in 46.7% (7/15), and venous wall was involved in 40.0% (6/15).

CONCLUSIONS

Use of PP as venous substitute during PD + VR is safe and feasible with an acceptable postoperative morbidity, and a decreased but asymptomatic venous patency after 12 weeks which should question the role of anticoagulation therapy.

Patency for autologous vein is superior to cadaveric vein in portal-mesenteric venous reconstruction

BACKGROUND

Portal venous reconstruction (PVR) is often needed during resection of hepatopancreato-biliary (HPB) malignancies. Primary repair (PR), autologous vein (AV), or cryopreserved cadaveric vein (CCV) are frequently utilized, however relative patency is not well studied.

METHODS

All patients undergoing PVR between 2007-2019 at our center were identified. 3-year primary patency (PP), overall survival (OS), and survival-adjusted patency (SAP) were evaluated with Kaplan-Meier and Cox proportional hazards modeling.

RESULTS

One-hundred-twenty patients were identified with a median follow-up of 11 months. PR, AV, and CCV reconstruction were used in 28 (23%), 35 (29%), and 57 (48%) patients, respectively, with two (7%), four (11%), and 29 (51%) thromboses, respectively. 3-year PP was greater for both primary repair (90%) and AV (83%) compared to CCV (33%, both p<0.001). On multivariable analysis, CCV had worse 3-year PP (HR 7.89, p=0.005) and SAP (HR 2.09, p=0.02) compared to PR; AV reconstruction had equivalent oncologic and patency-related outcomes to PR (p>0.4 for both comparisons).

CONCLUSIONS

Primary patency for PR and AV reconstruction is superior to CCV for PVR during resection of HPB malignancies. AV conduit should be the preferred choice of reconstruction when PR is not achievable. Surgeons should only use CCV when factors preclude PR/AV reconstruction.

Extent of venous resection during pancreatectomy-finding the balance of technical possibility and feasibility

The improvement of effective multidrug agents has allowed more patients to undergo resection for pancreatic cancer (PC). In the conversion cases of initially unresectable PC after induction chemotherapy, pancreatic surgeons often encounter challenging vein resections cases such as those of long-segment portal vein (PV)/superior mesenteric vein (SMV) encasement or occlusion of the distal (caudal) SMV. Given the lack of consensus for the optimal approach for major vein resections and reconstructions in these situations, this review summarizes the literature on this topic and provides the best currently available approaches for challenging vein reconstruction cases. For long-segment PV/SMV encasement, tips for direct end-to-end anastomosis without grafts and the splenic vein (SpV) reconstruction to prevent left-side portal hypertension will be introduced. For distal SMV encasement, several bypass techniques to deal with collateralizations will be introduced. Even though some high-volume PC centers are obtaining favorable outcomes for challenging vein resection cases, existing evidence on this topic is limited. It is essential to organize the well-designed international multicenter studies for the small population of challenging vein resection cases. With the emergence of effective chemotherapies, the number of PC patients who can undergo curative resection is increasing. Achieving more successful vessel resection and reconstruction in the treatment of PC is a common goal that pancreatic surgeons should focus on together.

Parachute technique for portal vein reconstruction during pancreaticoduodenectomy with portal vein resection in patients with pancreatic head cancer

BACKGROUND

The most appropriate venous reconstruction method remains debatable when a long section of portal vein (PV) and/or superior mesenteric vein (SMV) must be resected in patients undergoing a pancreaticoduodenectomy (PD). The aim of the present study was to describe the technical details of the parachute technique, a modified end-to-end anastomotic maneuver that can be used in the above-mentioned circumstances, and to investigate its safety and feasibility.

STUDY DESIGN

Patients who underwent venous reconstruction using the parachute technique after receiving a PD with PV resection for pancreatic cancer between January 2014 and March 2019 were retrospectively reviewed. For the parachute technique, the posterior wall was sutured in a continuous fashion while the stitches were left untightened. The stitches were then tightened from both sides after the running suture of the posterior wall had been completed, thereby dispersing the tension applied to the stitched venous wall when the venous ends were brought together and solving any problems that would otherwise have been caused by over-tension. The postoperative outcomes and PV patency were then investigated.

RESULTS

Fifteen patients were identified. The median length of the resected PV/SMV measured in vivo was 5 cm (range, 3-6 cm). The splenic vein was resected in all the patients and was reconstructed in 13 patients (87%). The overall postoperative complication rate (≥ Clavien-Dindo grade I) was 60%, while a major complication (≥ Clavien-Dindo grade IIIa) occurred in 1 patient (7%). No postoperative deaths occurred in this series. The PV patency at 1 year was 87%.

CONCLUSION

The parachute technique is both safe and feasible and is a simple venous reconstruction procedure suitable for use in cases undergoing PD when the distance between the resected PV and SMV is relatively long.

Graft type for superior mesenteric and portal vein reconstruction in pancreatic surgery - A systematic review

BACKGROUND

Contemporary practice for superior mesenteric/portal vein (SMV-PV) reconstruction during pancreatectomy with vein resection involves biological (autograft, allograft, xenograft) or synthetic grafts as a conduit or patch. The aim of this study was to systematically review the safety and feasibility of the different grafts used for SMV-PV reconstruction.

METHODS

A systematic search was performed in PubMed and Embase according to the PRISMA guidelines (January 2000-March 2020). Studies reporting on ≥ 5 patients undergoing reconstruction of the SMV-PV with grafts during pancreatectomy were included. Primary outcome was rate of graft thrombosis.

RESULTS

Thirty-four studies with 603 patients were included. Four graft types were identified (autologous vein, autologous parietal peritoneum/falciform ligament, allogeneic cadaveric vein/artery, synthetic grafts). Early and overall graft thrombosis rate was 7.5% and 22.2% for synthetic graft, 5.6% and 11.7% for autologous vein graft, 6.7% and 8.9% for autologous parietal peritoneum/falciform ligament, and 2.5% and 6.2% for allograft. Donor site complications were reported for harvesting of the femoral, saphenous, and external iliac vein. No cases of graft infection were reported for synthetic grafts.

CONCLUSION

In selected patients, autologous, allogenic or synthetic grafts for SMV-PV reconstruction are safe and feasible. Synthetic grafts seems to have a higher incidence of graft thrombosis.

Venous Reconstruction During Pancreatectomy Using Polytetrafluoroethylene Grafts: A Single-Center Experience with Standardized Perioperative Management

BACKGROUND

Although primary end-to-end anastomosis is preferred for portal vein-superior mesenteric vein (PV-SMV) reconstruction, interposition graft use may be required in some situations. We investigated the efficacy of polytetrafluoroethylene (PTFE) grafts when used during pancreatectomy in this context.

METHODS

From 2014 to 2019, 19 patients who underwent pancreatectomy requiring PV-SMV reconstruction using ringed PTFE grafts were entered prospectively into a clinical database (NCT02871336, CNIL No. Sy50955016U). Unfractionated heparin was used during the first 24 h postoperatively. The administration of low-molecular-weight heparin was initiated twice a day (two injections of 1 mg/kg enoxaparin) on postoperative day 2 and was continued until the first clinical follow-up. Patency was assessed by CT scan before home discharge. Patients were switched to antiplatelet therapy (75 mg of aspirin-based drug Kardegic^®) without a deadline.

RESULTS

Pancreatoduodenectomy was the most commonly performed procedure (15 patients, 79%), and pancreatic duct adenocarcinoma was the predominant etiology (17 patients, 89%). The median PTFE graft diameter and length were 10 mm and 8 cm, respectively. The median clamping time was 25 min. The overall severe morbidity and 90-day mortality values were 21% and 10%, respectively. None of the patients experienced anticoagulation-related morbidity or PTFE graft-related infection. The 6-month PTFE graft patency rate was 68%. Patients who underwent distal pancreatectomy showed a higher late thrombosis rate than those who underwent a pancreaticoduodenectomy (50% vs. 8%, p = 0.049). The median long-term PTFE graft patency duration was 37 months.

CONCLUSIONS

PTFE reconstruction can be safely performed with simple perioperative management in cases requiring interposition graft use.

Vascular Resection for Pancreatic Cancer: 2019 French Recommendations Based on a Literature Review From 2008 to 6-2019

Introduction: Vascular resection remains a subject of debate in the management of Pancreatic Ductal Adenocarcinoma (PDAC). These French recommendations were drafted on behalf of the French National Institute of Cancer (INCA-2019).

Material and Methods: A systematic literature search, with PubMed, Medline® (OvidSP), EMBASE, the Cochrane Library, was performed for abstracts published in English from January 2008 to June 2019, and identified systematic reviews/metaanalyses, retrospective analyses and case series dedicated to vascular resections in the setting of PDAC. All selected articles were graded for level of evidence and strength of recommendation was given according to the GRADE system.

Results: Neoadjuvant treatment should be performed rather than direct surgery in borderline and locally advanced non-metastatic PDAC with venous and/or arterial infiltration (T4 stage). Patients who respond or those with stable disease and good performance status should undergo surgical exploration to assess resectability because cross-sectional imaging often fails to identify the extent of the remaining viable tumor. Combining vascular resection with pancreatectomy in these cases increases the feasibility of curative resection which is still the only option to improve long-term survival. Venous resection (VR) is recommended if resection is possible in the presence of limited lateral or circumferential involvement but without venous occlusion and in the absence of arterial contact with the celiac axis (CA; cephalic tumors) or the superior mesenteric artery (SMA; all tumor locations) (Grade B). The patients should be in good general condition because mortality and morbidity are higher than following pancreatectomy without VR (Grade B). In case of planned VR, neoadjuvant treatment is recommended since it improves both rate of R0 resections and survival compared to upfront surgery (Grade B). Due to their complexity and specificities, arterial resection (AR; mainly the hepatic artery (HA) or the CA) must be discussed in selected patients, in multidisciplinary team meetings in tertiary referral centers, according to the tumor location and the type of arterial extension. In case of invasion of a short segment of the common HA, resection with arterial reconstruction may be proposed after neoadjuvant therapy. In case of SMA invasion, neoadjuvant therapy may be followed by laparotomy with dissection and biopsy of peri-arterial tissues. A pancreaticoduodenectomy (PD) with SMA-resection is not recommended if the frozen section examination is positive (Grade C). In case of distal PDAC with invasion of the CA, a distal pancreatectomy with CA-resection without arterial reconstruction may be proposed after neoadjuvant therapy and radiologic embolization of the CA branches (expert opinion).

Conclusion: For PDAC with vascular involvement, neoadjuvant treatment followed by pancreatectomy with venous resection or even arterial resection can be proposed as a curative option in selected patients with selected vascular involvement.

Comparison of Different Thawing Protocols in Human Cryopreserved Venous Grafts

BACKGROUND

The aim of our study was to assess the impact of different thawing protocols on morphological changes arising in cryopreserved human saphenous vein grafts.

METHODS

The study was performed in 12 saphenous vein grafts harvested in brain death donors. Storage in the vapor phase of liquid nitrogen for 3 or 5 years followed. Two thawing protocols were tested: slow thawing in a refrigerator at temperature +4°C for 2 hr and rapid thawing-in a water bath at +37°C. Grafts were processed for scanning electron microscopy. Comparisons of continuous parameters under study between experimental groups were performed using the t-test (age, cold ischemia time, exposure to cryoprotectant, time of storage, total thawing time, mean thawing rate, morphology scoring of thawed HSVG) and the median test (HSVG length). Categorical parameters (sex and blood group) were formally tested using the chi-square test.

RESULTS

All samples were evaluated according to morphological changes and scored in terms of morphologically intact endothelium, confluent endothelium with structural inhomogeneity, disruption of the intercellular contacts, separation of the endothelial cells, complete loss of the endothelium, and damage of the subendothelial layers. There is no statistically significant difference between the sample sets at the significance level of 0.05. There was no association with donors' age, sex, and time of storage.

CONCLUSIONS

Human cryopreserved saphenous vein grafts in our experimental work showed no difference in terms of structural deterioration of the endothelial surface and basal membrane depending on different thawing protocols used.

Safety and efficacy of venous reconstruction in liver resection using cryopreserved homologous veins

BACKGROUND

Only a few studies have reported the resection and reconstruction of major hepatic veins during hepatectomy. Here, we present our strategy and techniques for venous reconstruction with cryopreserved homologous veins, and describe the surgical outcome.

METHODS

Among 2,387 hepatectomy patients, 39 patients who required hepatic venous reconstruction were reviewed retrospectively. Venous reconstruction was performed to secure a non-congested liver remnant volume of at least 40% of the total liver volume.

RESULTS

There was no operative mortality, and the severe morbidity rate was 5% in this series. A total of 41 veins were reconstructed; 30 with homologous veins (73.2%) and 11 with autologous veins (26.8%), with the middle hepatic vein being the most frequent (n = 23, 56%). Interposition grafting was performed more often (P = 0.003), the length of the venous resection was longer (P = 0.007), and pathologic wall infiltration of the vein was revealed more often (P = 0.002) in the homologous graft group than in the autologous graft group. The 1-, 2-, and 3-year overall patency of the reconstructed veins was 55.4%, 46.3%, and 46.3%, respectively.

CONCLUSIONS

Aggressive venous reconstruction during hepatectomy using cryopreserved homologous veins is a feasible option with satisfactory short-term outcomes, and may be warranted to improve operative safety.