Antithrombin therapy in pancreas retransplantation and pancreas-after-kidney/pancreas-transplantation-alone patients

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.

Pretreatment with Warfarin Attenuates the Development of Ischemia/Reperfusion-Induced Acute Pancreatitis in Rats

In acute pancreatitis (AP), pancreatic damage leads to local vascular injury, manifesting as endothelial damage and activation, increased vascular permeability, leukocyte rolling, sticking and transmigration to pancreatic tissue as well as activation of coagulation. Previous studies have shown that pretreatment with heparin or acenocoumarol inhibits the development of AP. The aim of the present study was to check the impact of pretreatment with warfarin, an oral vitamin K antagonist, on the development of ischemia/reperfusion-induced AP in rats. AP was induced by pancreatic ischemia followed by reperfusion of the gland. Warfarin (90, 180 or 270 µg/kg/dose) or vehicle were administered intragastrically once a day for 7 days before induction of AP. The effect of warfarin on the severity of AP was assessed 6 h after pancreatic reperfusion. The assessment included histological, functional, and biochemical analyses. Pretreatment with warfarin given at a dose of 90 or 180 µg/kg/dose increased the international normalized ratio and reduced morphological signs of pancreatic damage such as pancreatic edema, vacuolization of acinar cells, necrosis and the number of hemorrhages. These effects were accompanied by an improvement of pancreatic blood flow and a decrease in serum level amylase, lipase, pro-inflammatory interleukin-1β and plasma level of D-dimer. In contrast, pretreatment with warfarin given at a dose of 270 µg/kg/dose led to an increase in severity of pancreatic damage and biochemical indicators of AP. In addition, this dose of warfarin resulted in deaths in some animals. Pretreatment with low doses of warfarin inhibits the development of AP induced by pancreatic ischemia followed by reperfusion.

Outcomes after pancreas retransplantation: is the juice worth the squeeze?

PURPOSE OF REVIEW

Pancreas retransplantations are rarely carried out, and their outcomes are still debatable because of a lack of studies and clinical series on this issue.

RECENT FINDINGS

In general, pancreas retransplantations achieve similar or even higher patient survival than primary transplantations; however, it should be noted that this finding may be biased, as only healthier patients are selected for retransplantation. Graft survival in retransplantations is usually lower than that in primary transplantation, but this comparison may also be biased, as most retransplantations are solitary pancreas transplantations (which are known to have lower graft survival), whereas primary transplantations are mostly simultaneous kidney-pancreas transplantations. Technical loss is similar between primary pancreas transplantations and pancreas retransplantations, but the occurrence of surgical complications is greater in the latter.

SUMMARY

This review summarizes the literature on pancreas retransplantations, comparing them with primary transplantations, and demonstrates that in selected patients in experienced centres, retransplantation can be a valid and effective option for returning the patient to an insulin-free state.

Antithrombin: anti-inflammatory properties and clinical applications

Many humoral and cellular components participate in bidirectional communication between the coagulation and inflammation pathways. Natural anticoagulant proteins, including antithrombin (AT), tissue factor pathway inhibitor, and protein C, suppress proinflammatory mediators. Conversely, inflammation blunts anticoagulant activity and, when uncontrolled, promotes systemic inflammation-induced coagulation, such as those that occur in disseminated intravascular coagulation and severe sepsis. This review discusses the mechanisms of action and clinical use of AT concentrate in critically ill patients and in the settings of perioperative anticoagulation management for surgery and obstetrics. AT is a serine protease inhibitor with broad anticoagulant activity and potent anti-inflammatory properties. In clinical conditions associated with hereditary or acquired AT deficiency, administration of AT concentrate has been shown to restore proper haemostasis and attenuate inflammation. Of note, AT modulates inflammatory responses not only by inhibiting thrombin and other clotting factors that induce cytokine activity and leukocyte-endothelial cell interaction, but also by coagulation-independent effects, including direct interaction with cellular mediators of inflammation. An increasing body of evidence suggests that AT concentrate may be a potential therapeutic agent in certain clinical settings associated with inflammation. In addition to the well-known anticoagulation properties of AT for the treatment of hereditary AT deficiency, AT also possesses noteworthy anti-inflammatory properties that could be valuable in treating acquired AT deficiency, which often result in thrombotic states associated with an inflammatory component.

Pancreatic retransplantation is associated with poor allograft survival: an update of the United Network for Organ Sharing database

The aim of the study was to assess outcomes of pancreas retransplantation versus primary pancreas transplantation.

METHODS

Data from the United Network for Organ Sharing database on all adult (age, ≥18 years) subjects who received pancreas and kidney-pancreas transplants between 1996 and 2012 were analyzed (n = 20,854). The subjects were analyzed in the following 2 groups: retransplant (n = 1149) and primary transplant (n = 19,705).

RESULTS

Kaplan-Meier analysis demonstrated significantly different patient survival (P < 0.0001) and death-censored graft survival (P < 0.0001) between the primary transplant versus retransplant subjects. Allograft survival was significantly poorer in the retransplantation group. Patient survival was greater in the retransplant group.

CONCLUSIONS

The results of our study differ from previous studies, which showed similar allograft survival in primary and secondary pancreas transplants. Further studies may elucidate specific patients who will benefit from retransplantation. At the present time, it would appear that pancreas retransplantation is associated with poor graft survival and that retransplantation should not be considered for all patients with primary pancreatic allograft failure.

Outcomes of pancreas retransplantation

BACKGROUND

Pancreas retransplantation is associated with increased rates of technical failure and rejection compared to other organ transplants. As such, it is not routinely done, and outcomes are mostly known through registry data. Here we analyze the outcomes of primary versus retransplant for all pancreas transplants done in our program over nearly 35 years.

METHODS

Donor and recipient characteristics and outcomes data were prospectively gathered and recorded in our institutional database. Outcomes of primary and retransplants were reported overall, and then subgrouped by number (second, third, fourth). An in-depth analysis of transplants done after 2003 was included. Rates of technical failure, 1 year acute rejection, graft survival, and patient survival were compared.

RESULTS

Two thousand one hundred forty-five pancreas transplants were performed at our institution between 1978 and 2012. Four hundred fifteen of these were retransplants. Improvements were seen in technical failure rates and graft survival for both primary and retransplants over time. There were no significant differences in technical failure or patient survival for primary versus retransplants overall, or by transplant number (second, third, fourth). Modern era retransplants had more acute rejection in the first year after transplantation. Retransplants (vs primary) had decreased mid-term death censored graft survival. Transplant type continues to be an important driver of outcome.

CONCLUSIONS

Retransplant outcomes have improved over time, yet increased rejection and immunologic graft loss rates remain associated with pancreas retransplantation. In contrast, risk of technical failure and patient death for primary versus retransplants are similar. Therefore, pancreas retransplantation in highly selected candidates should be considered in experienced centers.

Donor risk factors, retrieval technique, preservation and ischemia/reperfusion injury in pancreas transplantation

PURPOSE OF REVIEW

Pancreas transplantation is still hampered by a high incidence of early graft loss, and organ quality concerns result in high nonrecovery/discard rates. Demographic donor characteristics, surgical retrieval strategy, preservation fluid and ischemia time are crucial factors in the process of organ selection and are discussed in this review.

RECENT FINDINGS

The donor shortage is driving an increasing utilization of nonideal organs which would previously have been identified as unsuitable. Recent literature suggests that organs from extended criteria donors - older (>45 years), BMI >30  kg/m(2), and donation after cardiac death (DCD) - can achieve the same graft and patient survival as those from standard criteria donors, with the proviso that the accumulation of risk factors and long ischemic times should be avoided. Visual assessment of the pancreas is advisable before declining/accepting a pancreas. University of Wisconsin represents the gold standard solution; however, histidine-tryptophan-ketoglutarate and Celsior result in equal outcomes if cold ischemia time (CIT) is less than 12  h. Currently in pancreas transplantation, there is no proven effective ischemia/reperfusion injury prophylaxis than trying to keep CIT as short as possible.

SUMMARY

Demographic risk factors, inspection of the pancreas by an experienced surgeon and predicted CIT are crucial factors in deciding whether to accept a pancreas for transplantation. However, there is a need for an improved evidence base to determine where to set the 'cut-off' for unsuitable pancreatic grafts.