Susceptibility-directed anticoagulation after pancreas transplantation: A single-center retrospective study

The concept of immunothrombosis in pancreas transplantation

Early failure of a pancreatic allograft due to complete thrombosis has an incidence of approximately 10% and is the main cause of comorbidity in pancreas transplantation. Although several risk factors have been identified, the exact mechanisms leading to this serious complication are still unclear. In this review, we define the roles of the individual components involved during sterile immunothrombosis-namely endothelial cells, platelets, and innate immune cells. Further, we review the published evidence linking the main risk factors for pancreatic thrombosis to cellular activation and vascular modifications. We also explore the unique features of the pancreas itself: the vessel endothelium, specific vascularization, and relationship to other organs-notably the spleen and adipose tissue. Finally, we summarize the therapeutic possibilities for the prevention of pancreatic thrombosis depending on the different mechanisms such as anticoagulation, anti-inflammatory molecules, endothelium protectors, antagonism of damage-associated molecular patterns, and use of machine perfusion.

A study on the prevention of thrombosis after simultaneous pancreas-kidney transplantation

BACKGROUND

Renal failure is one of the most common chronic complications of diabetes. Simultaneous pancreas-kidney transplantation (SPK) is considered the preferred treatment for individuals with diabetes and chronic renal failure. This procedure has demonstrated efficacy in enhancing the quality of life for patients and minimizing the complications associated with diabetes.

OBJECTIVE

In this study, we analyzed the incidence and safety of complications in different thrombosis prevention techniques post simultaneous pancreas-kidney transplantation (SPK).

METHODS

Patients who underwent SPK between January 2019 and December 2022 were selectively categorized into two groups: the heparin group and the non-heparin group depending on the utilization of low molecular weight heparin. The occurrence of complications and clinical outcomes were subsequently calculated in each group.

RESULTS

In this study, we included a total of 58 recipients who underwent SPK, with 36 in the heparin group and 22 in the non-heparin group. Among the 58 participants, there were 3 cases of pancreatic thrombosis complications, with 2 cases (5.6%) in the heparin group and 1 case (4.6%) in the non-heparin group, and the differences were not statistically significant (P> 0.05). Regarding gastrointestinal bleeding, there were 17 cases out of the total 58 patients, with 14 cases (38.9%) in the heparin group and 3 cases (13.6%) in the non-heparin group, and the difference was statistically significant (P< 0.05).

CONCLUSION

After surgery, the use of low molecular weight heparin anticoagulation may increase the likelihood of experiencing gastrointestinal bleeding. Prior to the surgery, a comprehensive evaluation of the coagulation status and medical history of the patient should be performed, enabling stratification of risks involved. Based on this assessment, either low-molecular-weight heparin or aspirin should be selected as a preventive measure against thrombosis.

Pancreatic Allograft Thrombosis: Implementation of the CPAT-Grading System in a Retrospective Series of Simultaneous Pancreas-Kidney Transplantation

Pancreatic graft thrombosis (PAT) is a major surgical complication, potentially leading to graft loss. The recently proposed Cambridge Pancreas Allograft Thrombosis (CPAT) grading system provides diagnostic, prognostic and therapeutic recommendations. The aim of the present study was to retrospectively assess computed tomography angiography (CTA) examinations performed routinely in simultaneous pancreas-kidney (SPK) recipients to implement the CPAT grading system and to study its association with the recipients' outcomes. We retrospectively studied 319 SPK transplant recipients, who underwent a routine CTA within the first 7 postoperative days. Analysis of the CTA scans revealed PAT in 215 patients (106 grade 1, 85 grade 2, 24 grade 3), while 104 showed no signs. Demographic data of the patients with and without PAT (thrombosis and non-thrombosis group) were not significantly different, except for the higher number of male donors in the thrombosis group. Pancreatic graft survival was significantly shorter in the thrombosis group. Graft loss due to PAT was significantly associated with grade 2 and 3 thrombosis, while it did not differ for recipients with grade 0 or grade 1 thrombosis. In conclusion, the CPAT grading system was successfully implemented in a large series of SPK transplant recipients and proved applicable in clinical practice.

Heparin Thromboprophylaxis in Simultaneous Pancreas-Kidney Transplantation: A Systematic Review and Meta-Analysis of Observational Studies

Thrombosis is a leading causes of pancreas graft loss after simultaneous pancreas kidney (SPK), pancreas after kidney (PAK), and pancreas transplant alone (PTA). There remains no standardized thromboprophylaxis protocol. The aim of this systematic review and meta-analysis is to evaluate the impact of heparin thromboprophylaxis on the incidence of pancreas thrombosis, pancreas graft loss, bleeding, and secondary outcomes in SPK, PAK, and PTA. Following PRISMA guidelines, we systematically searched BIOSIS®, PubMed®, Cochrane Library®, EMBASE®, MEDLINE®, and Web of Science® on April 21, 2021. Primary peer-reviewed studies that met inclusion criteria were included. Two methods of quantitative synthesis were performed to account for comparative and non-comparative studies. We included 11 studies, comprising of 1,122 patients in the heparin group and 236 patients in the no-heparin group. When compared to the no-heparin control, prophylactic heparinization significantly decreased the risk of early pancreas thrombosis and pancreas loss for SPK, PAK and PTA without increasing the incidence of bleeding or acute return to the operating room. Heparin thromboprophylaxis yields an approximate two-fold reduction in both pancreas thrombosis and pancreas loss for SPK, PAK and PTA. We report the dosage, frequency, and duration of heparin administration to consolidate the available evidence.

Improved surgical outcomes following simultaneous pancreas-kidney transplantation in the contemporary era

BACKGROUND

Complications leading to early technical failure have been the Achilles' heel of simultaneous pancreas-kidney transplantation (SPKT). The study purpose was to analyze longitudinally our experience with early surgical complications following SPKT with an emphasis on changes in practice that improved outcomes in the most recent era.

STUDY DESIGN

Single center retrospective review of all SPKTs from 11/1/01 to 8/12/20 with enteric drainage. Early relaparotomy was defined as occurring within 3 months of SPKT. Patients were stratified into two sequential eras: Era 1 (E1): 11/1/01-5/30/13; Era 2 (E2) 6/1/13-8/12/20 based on changes in practice that occurred pursuant to donor age and pancreas cold ischemia time (CIT).

RESULTS

255 consecutive SPKTs were analyzed (E1, n = 165; E2, n = 90). E1 patients received organs from older donors (mean E1 27.3 vs. E2 23.1 years) with longer pancreas cold CITs) (mean E1 16.1 vs. E2 13.3 h, both p < .05). E1 patients had a higher early relaparotomy rate (E1 43.0% vs. E2 14.4%) and were more likely to require allograft pancreatectomy (E1 9.1% vs. E2 2.2%, both p < .05). E2 patients underwent systemic venous drainage more frequently (E1 8% vs. E2 29%) but pancreas venous drainage did not influence either relaparotomy or allograft pancreatectomy rates. The most common indications for early relaparotomy in E1 were allograft thrombosis (11.5%) and peri-pancreatic phlegmon/abscess (8.5%) whereas in E2 were thrombosis, pancreatitis/infection, and bowel obstruction (each 3%).

CONCLUSION

Maximizing donor quality (younger donors) and minimizing pancreas CIT are paramount for reducing early surgical complications following SPKT.

Effective Technique for Pancreas Transplantation by Iliac Vascular Transposition, Without Heparin-Based Anticoagulation Therapy

BACKGROUND

To evaluate patients undergoing a new procedure, iliac vascular transposition, in pancreas transplantation regarding the risk of thrombosis and graft survival without heparin-based anticoagulation therapy.

METHODS

Iliac vascular transposition (IVT) involves changing the positions of the external iliac artery and vein relative to each other. In this study, this technique was evaluated in patients undergoing the procedure compared with patients not undergoing the procedure (iliac vascular parallel (IVP) group).

RESULTS

No patients received prophylactic heparin therapy. Two patients in the IVP group (n = 26) developed complete thrombosis and six developed partial thrombosis, compared with no patients with complete thrombosis and one with partial thrombosis in the IVT group (n = 29). The cumulative incidence of thrombosis was significantly higher in the IVP group (p < 0.01). Cox regression revealed that not receiving iliac vascular transposition was the only significant risk factor for thrombosis (odds ratio: 10.1, 95% confidence interval: 1.27-81.2; p = 0.03). One-year graft survival was significantly better in the IVT group vs IVP group (p = 0.03).

CONCLUSIONS

IVT in pancreas transplantation is a simple technique that results in a lower thrombosis risk and better graft survival rates without heparin-based anticoagulation therapy.

Suture ligation for submucosal hemostasis during hand-sewn side-to-side duodeno-ileostomy in simultaneous pancreas and kidney transplantation

BACKGROUND

Enteric anastomotic (EA) bleeding is a potentially life-threatening surgical complication associated with enteric anastomosis during simultaneous pancreas and kidney transplantation (SPKT).

AIM

To investigate whether suture ligation (SL) for submucosal hemostasis during hand-sewn enteric anastomosis could decrease the morbidity of early EA bleeding in SPKT.

METHODS

We compared the outcomes of 134 patients classified into SL (n = 44) and no SL (NSL) groups (n = 90). This study adheres to the declarations of Istanbul and Helsinki and all donors were neither paid nor coerced.

RESULTS

During the first postoperative week, the EA bleeding rate in the SL group was lower than that in the NSL group (2.27% vs 15.56%; P = 0.021); no relationship was found between EA bleeding and donor age, mean pancreatic cold ischemia time, platelet count, prothrombin time international normalized rate, activated partial thromboplastin time, and thrombin time. Anastomotic leakage was observed in one case in the SL group at postoperative day (POD) 14 and in one case at POD 16 in the NSL group (P = 0.754). No significant difference was found between the two groups in the patient survival, pancreas graft survival, or kidney graft survival.

CONCLUSION

SL for submucosal hemostasis during hand-sewn enteric anastomosis in SPKT can decrease the morbidity of early EA bleeding without increasing the anastomotic leakage rate.

Risk Factors for Early Pancreatic Allograft Thrombosis Following Simultaneous Pancreas-Kidney Transplantation: A Systematic Review

Simultaneous pancreas-kidney (SPK) transplantation remains the most effective treatment for providing consistent and long-term euglycemia in patients having type 1 diabetes with renal failure. Thrombosis of the pancreatic vasculature continues to contribute significantly to early graft failure and loss. We compared the rate of thrombosis to graft loss and systematically reviewed risk factors impacting early thrombosis of the pancreas allograft following SPK transplantation. We searched the MEDLINE, EMBASE, The Cochrane Library, and PREMEDLINE databases for studies reporting thrombosis following pancreas transplantation. Identified publications were screened for inclusion and synthesized into a data extraction sheet. Sixty-three studies satisfied eligibility criteria: 39 cohort studies, 22 conference abstracts, and 2 meta-analyses. Newcastle-Ottawa Scale appraisal of included studies demonstrated cohort studies of low bias risk; 1127 thrombi were identified in 15 936 deceased donor, whole pancreas transplants, conferring a 7.07% overall thrombosis rate. Thrombosis resulted in pancreatic allograft loss in 83.3% of reported cases. This review has established significant associations between donor and recipient characteristics, procurement and preservation methodology, transplantation technique, postoperative management, and increased risk of early thrombosis in the pancreas allograft. Further studies examining the type of organ preservation fluid, prophylactic heparin protocol, and exocrine drainage method and early thrombosis should also be performed.

Working towards an ERAS Protocol for Pancreatic Transplantation: A Narrative Review

Enhanced recovery after surgery (ERAS) initially started in the early 2000s as a series of protocols to improve the perioperative care of surgical patients. They aimed to increase patient satisfaction while reducing postoperative complications and postoperative length of stay. Despite these protocols being widely adopted in many fields of surgery, they are yet to be adopted in pancreatic transplantation: a high-risk surgery with often prolonged length of postoperative stay and high rate of complications. We have analysed the literature in pancreatic and transplantation surgery to identify the necessary preoperative, intra-operative and postoperative components of an ERAS pathway in pancreas transplantation.

Anticoagulation in simultaneous pancreas kidney transplantation - On what basis?

BACKGROUND

Despite technical refinements, early pancreas graft loss due to thrombosis continues to occur. Conventional coagulation tests (CCT) do not detect hypercoagulability and hence the hypercoagulable state due to diabetes is left untreated. Thromboelastogram (TEG) is an in-vitro diagnostic test which is used in liver transplantation, and in various intensive care settings to guide anticoagulation. TEG is better than CCT because it is dynamic and provides a global hemostatic profile including fibrinolysis.

AIM

To compare the outcomes between TEG and CCT (prothrombin time, activated partial thromboplastin time and international normalized ratio) directed anticoagulation in simultaneous pancreas and kidney (SPK) transplant recipients.

METHODS

A single center retrospective analysis comparing the outcomes between TEG and CCT-directed anticoagulation in SPK recipients, who were matched for donor age and graft type (donors after brainstem death and donors after circulatory death). Anticoagulation consisted of intravenous (IV) heparin titrated up to a maximum of 500 IU/h based on CCT in conjunction with various clinical parameters or directed by TEG results. Graft loss due to thrombosis, anticoagulation related bleeding, radiological incidence of partial thrombi in the pancreas graft, thrombus resolution rate after anticoagulation dose escalation, length of the hospital stays and, 1-year pancreas and kidney graft survival between the two groups were compared.

RESULTS

Seventeen patients who received TEG-directed anticoagulation were compared against 51 contemporaneous SPK recipients (ratio of 1: 3) who were anticoagulated based on CCT. No graft losses occurred in the TEG group, whereas 11 grafts (7 pancreases and 4 kidneys) were lost due to thrombosis in the CCT group (P = 0.06, Fisher's exact test). The overall incidence of anticoagulation related bleeding (hematoma/ gastrointestinal bleeding/ hematuria/ nose bleeding/ re-exploration for bleeding/ post-operative blood transfusion) was 17.65% in the TEG group and 45.10% in the CCT group (P = 0.05, Fisher's exact test). The incidence of radiologically confirmed partial thrombus in pancreas allograft was 41.18% in the TEG and 25.50% in the CCT group (P = 0.23, Fisher's exact test). All recipients with partial thrombi detected in computed tomography (CT) scan had an anticoagulation dose escalation. The thrombus resolution rates in subsequent scan were 85.71% and 63.64% in the TEG group vs the CCT group (P = 0.59, Fisher's exact test). The TEG group had reduced blood product usage {10 packed red blood cell (PRBC) and 2 fresh frozen plasma (FFP)} compared to the CCT group (71 PRBC/ 10 FFP/ 2 cryoprecipitate and 2 platelets). The proportion of patients requiring transfusion in the TEG group was 17.65% vs 39.25% in the CCT group (P = 0.14, Fisher's exact test). The median length of hospital stay was 18 days in the TEG group vs 31 days in the CCT group (P = 0.03, Mann Whitney test). The 1-year pancreas graft survival was 100% in the TEG group vs 82.35% in the CCT group (P = 0.07, log rank test) and, the 1-year kidney graft survival was 100% in the TEG group vs 92.15% in the CCT group (P = 0.23, log tank test).

CONCLUSION

TEG is a promising tool in guiding judicious use of anticoagulation with concomitant prevention of graft loss due to thrombosis, and reduces the length of hospital stay.