Impact of blood amylase peak over vascular graft thrombosis in pancreas transplantation

Exploring definitions of graft pancreatitis following pancreas transplantation: A scoping review

Despite the clinical relevance of graft pancreatitis (GP) after pancreas transplantation (PT), a universally accepted definition is lacking. Aim of this scoping review was to provide a systematic overview of GP definitions reported in the literature. MEDLINE, Web of Science and Embase were searched for relevant articles. Prospective/retrospective studies reporting a GP definition were included. The included series (n = 20) used four main criteria (clinical, biochemical, radiological and pathological) to define GP. Overall, 9 studies defined GP using a single criterion (n = 8 biochemical, n = 1 pathological), 7 series using two criteria (n = 3 clinical + biochemical, n = 3 biochemical + radiological, n = 1 clinical + radiological), 3 series using three criteria (n = 3 clinical + biochemical + radiological), and 1 series using four criteria. Overall, 20 definitions of GP were found. GP rate was reported by 19 series and ranged between 0% and 87%. This scoping review confirms that a universally accepted definition of GP is absent, and there is no consensus on the criteria on which it should be grounded. Future research should focus on developing a validated definition of GP.

Effect of donor pancreas extraction time on pancreas transplantation-a Swiss tertiary center experience

We aimed to assess the effect of donor pancreas extraction time (ET) on postoperative complications and graft function after pancreas transplantation (PT). We analyzed all consecutive donor pancreas procurements for the simultaneous pancreas and kidney transplantation (SPK) and the associated PT in a Swiss transplant center over a 20-year period. Pancreas ET was defined as the time from cold flush to static storage of the pancreas on ice. The primary endpoint was the effect of extraction time on surgical complications. Secondary endpoints comprised the effect of ET on graft function (insulin-free survival) and graft pancreatitis. Of 115 procured pancreas grafts the median donor pancreas ET was 65 min (IQR: 48-78 min). In multivariable analysis, ET did not negatively affect major complications (OR 1.41 [95% CI: .59-3.36]; p = .438) and insulin-free survival (HR 1.42 [95% CI: .55-3.63]; p = .459). The median CIT was 522 (441-608) min. CIT was associated with major complications (OR 2.51 [95% CI: 1.11-5.68]; p = .027), but without impact on insulin-free survival (HR 1.94 [95% CI: .84-4.48]; p = .119). Patients with and without graft pancreatitis had no statistically significant differences in ET and CIT (p = .164 and p = .47, respectively). In multivariable analysis, Amylase levels > 270 U/L on postoperative day 1 were significantly associated with major complications (OR 3.61 [95% CI: 1.06-12.32]; p = .040). Our results suggest that although no effect of ET on complications and graft function after PT was found, shorter CIT and less graft pancreatitis can have a positive impact on surgical complications. Results could possibly be influenced by the exceptional quality of the pancreas donors, with short travel distances and preservation times in Switzerland.

Early Increases in Posttransplant Pancreatic Enzymes Are Associated With Surgical Complications But Not Graft Failure Among Pancreas Transplant Recipients

OBJECTIVES

This study aimed to find the association between immediate postoperative increases in pancreatic enzymes and posttransplant complications among pancreas transplant recipients (PTRs).

METHODS

We analyzed all PTRs transplanted at the University of Wisconsin between June 2009 and September 2018. Enzyme levels were presented as a ratio of absolute numbers to the upper limit of normal value, with value >1 considered as abnormal. We specifically evaluated bleeding, fluid collections, and thrombosis complications based on the amylase or lipase ratios on day 1 (Amylase1, Lipase1) and maximum ratios within 5 days of transplant (Amylasemax, Lipasemax). For early complications, we focused on technical complications that occurred within 90 days of transplant. For long-term outcomes, we assessed patient and graft survival, and rejections.

RESULTS

There were a total of 443 PTRs, 287 were simultaneous pancreas and kidney recipients, and 156 were solitary pancreas recipients. Higher Amylase1, Liplase1, Amylasemax, and Lipasemax were associated with an increase in early complications, mainly need for pancreatectomy, fluid collections, bleeding complications, or graft thrombosis, particularly in the solitary pancreas group.

CONCLUSIONS

Our finding suggests that cases of early perioperative enzyme increase merit consideration for early imaging investigation to mitigate detrimental outcomes.

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.

Immediate post-operative complications (I): Post-operative bleeding; vascular origin: Thrombosis pancreatitis

Simultaneous pancreas-kidney transplantation is the treatment of choice for insulin-dependent diabetes that associates end-stage diabetic nephropathy, since it achieves not only a clear improvement in the quality of life, but also provides a long-term survival advantage over isolated kidney transplant. However, pancreas transplantation still has the highest rate of surgical complications among organ transplants. More than 70% of early graft losses are attributed to technical failures, that is, to a non-immunological cause. The so-called technical failures include graft thrombosis, bleeding, infection, pancreatitis, anastomotic leak and pancreatic fistula. Pancreatic graft thrombosis leads these technical complications as the most frequent cause of early graft loss. Currently most recipients receive postoperative anticoagulation with the aim of reducing the rate of thrombosis. Hemoperitoneum in the early postoperative period is a frequent cause of relaparotomy, but it is not usually associated with graft loss. The incidence of hemoperitoneum is clearly related to the use of anticoagulation in the postoperative period. Post-transplant pancreatitis is another cause of early postoperative complications, less frequent than the previous. In this review, we analyze the most common surgical complications that determine pancreatic graft losses.

Early protocol computer tomography and endovascular interventions in pancreas transplantation

BACKGROUND

Early vascular complications following pancreatic transplantation are not uncommon (3%-8%). Typically, cross-sectional imaging is requested in response to clinical change. We instituted a change in protocol to request imaging pre-emptively to identify patients with thrombotic complications.

METHODS

In 2013, protocol computer tomography angiography (CTA) at days 3-5 and day 10 following pancreas transplantation was introduced. A retrospective analysis of all pancreas transplants performed at our institution from January 2001 to May 2019 was undertaken.

RESULTS

A total of 115 patients received pancreas transplants during this time period. A total of 78 received pancreas transplant without routine CTA and 37 patients with the new protocol. Following the change in protocol, we detected a high number of subclinical thromboses (41.7%). There was a significant decrease in invasive intervention for thrombosis (78.6% before vs 30.8% after, p = .02), and graft survival was significantly higher (61.5% before vs 86.1% after, p = .04). There was also a significant reduction in the number of graft failures (all-cause) where thrombosis was present (23.4% before vs 5.6% after, p = .02). Patient survival was unaffected (p = .48).

CONCLUSIONS

Implementation of early protocol CTA identifies a large number of patients with subclinical graft thromboses that are more amenable to conservative management and significantly reduces the requirement for invasive intervention.

Splenic Vein Thrombosis Following Pancreas Transplantation: Identification of Factors That Support Conservative Management

Prophylaxis for graft portal/splenic venous thrombosis following pancreas transplant varies between institutions. Similarly, treatment of venous thrombosis ranges from early re-exploration to conservative management with anticoagulation. We wished to determine the prevalence of graft splenic vein (SV) thrombosis, as well as the clinical significance of non-occlusive thrombus observed on routine imaging. Records of 112 pancreas transplant recipients over a 5-year period at a single center were reviewed. Venous thrombosis was defined as absence of flow or presence of thrombus identified in any part of the graft SV on ultrasound. Thirty patients (27%) had some degree of thrombus or absence of flow in the SV on postoperative ultrasound. There were 5 graft losses in this group. Four were due to venous thrombosis, and occurred within 20 days of transplant. All patients with non-occlusive partial SV thrombus but normal arterial signal on Doppler ultrasound were successfully treated with IV heparin followed by warfarin for 3-6 months, and remained insulin independent. Findings of arterial signal abnormalities, such as absence or reversal of diastolic flow within the graft, require urgent operative intervention since this finding can be associated with more extensive thrombus that may lead to graft loss.

Clinical application of regulatory T cells in type 1 diabetes

Regulatory T cells (Tregs) are responsible for the maintenance of peripheral tolerance. Animal studies have shown that administration of Tregs can prevent type 1 diabetes (DM1). Several clinical trials attempted to induce Tregs with various agents, and thus provide long-term tolerance of β cells in DM1. Nevertheless, most of these studies have focused on clinical parameters (e.g. C-peptide) and not Treg numbers nor their function after treatment. Therefore, it is not possible to conclude if the majority of these therapies failed because the drugs did not induce Tregs, or if they failed despite Treg expansion. The current knowledge regarding Tregs, along with our experience in Treg therapy of patients with graft versus host disease, prompted us to use ex vivo expanded Tregs in 10 children with recent-onset DM1. No adverse effects in the treated individuals were observed. There was a significant increase in Treg number in peripheral blood immediately after the treatment administration, while the first clinical differences between treated and control patients were observed 4 months after Treg injection. Treated individuals had higher C-peptide levels and lower insulin requirements than non-treated children. Eleven months after diagnosis of DM1, there are still 2 individuals who are independent of exogenous insulin. These results indicate that autologous Tregs are a safe and well-tolerated therapy in children with DM1, which can inhibit or delay the destruction of pancreatic β cells. Additionally, Tregs can be a useful tool for local protection of transplanted pancreatic islets. Isolation and expansion of antigen-specific Tregs is one of the directions for future studies on cellular therapy of DM1.