Extreme Thrombocytosis after Pediatric Pancreatectomy with Islet Autotransplantation Is Unique Compared to Other Postsplenectomy States

Current practices in islet cell autotransplantation

INTRODUCTION

Chronic pancreatitis and recurrent acute pancreatitis comprise a spectrum of disease that results in complications related to exocrine and endocrine insufficiency and chronic pain with narcotic dependence and poor quality of life. The mainstay of therapy has been medical and endoscopic therapy; surgery, especially total pancreatectomy, was historically reserved for few select patients as the obligate exocrine insufficiency and pancreatogenic diabetes (type 3C) are challenging to manage. The addition of islet cell autotransplantation after total pancreatectomy helps to mitigate brittle type 3c diabetes and prevents mortality related to severe hypoglycemic episodes and hypoglycemic unawareness. There have been more recent data demonstrating the safety of surgery and the beneficial long-term outcomes.

AREAS COVERED

The purpose of this review is to describe the current practices in the field of islet cell autotransplantation including the selection and evaluation of patients for surgery, their preoperative work up and management, surgical approach, post-operative management and outcomes.

EXPERT OPINION

Total pancreatectomy and islet cell autotransplantation has the ability to drastically improve quality of life and prevent brittle diabetes for patients suffering with chronic pancreatitis.

Total pancreatectomy with islet autotransplantation reduces opioid use and improves nutritional support in children with debilitating pancreatitis

BACKGROUND

Chronic pancreatitis (CP) can result in opioid dependence and nutritional challenges in children. Total pancreatectomy with islet autotransplantation (TPIAT) is a viable surgical option in appropriately selected patients. We examined differences between children who met criteria for TPIAT versus those who did not and continued with non-operative management.

METHODS

Retrospective observational cohort study of patients evaluated for TPIAT between August 2014 and July 2020 was performed. Cohort-based analyses between TPIAT and non-TPIAT groups were performed.

RESULTS

Analyses included 121 patients, 69 of whom underwent TPIAT. Demographics, genetic risk factors, and anatomic variants did not differ between groups. TPIAT patients were more likely to have CP (88% vs 71%; p = 0.02), had higher median number of endoscopic retrograde cholangiopancreatography procedures (2.0 vs 1.0; p = 0.0001), and had higher likelihood of opioid use (61% vs 42%; p = 0.04) and nutritional supplementation (23% vs 4%; p = 0.004), compared to non-TPIAT. At 6 months post-TPIAT, patients had lower use of any analgesic pain medications (39% vs 73%; p = 0.0002) and lower use of opioids (9% vs 39%; p = 0.0006), compared to non-TPIAT patients at 6 months after evaluation. At 6 months post-TPIAT, rate of exclusively oral nutrition increased from 77% to 86%, and total parenteral nutrition use decreased from 13% to 0% (p = 0.02).

CONCLUSIONS

In children referred for TPIAT evaluation, there is greater burden of disease in those selected for operation, compared to patients who do not undergo operation. TPIAT achieves lower analgesic pain medication use compared to continuation with non-TPIAT management and achieves freedom from nutritional supplementation. Level of evidence: Retrospective comparative study, Level III.

Pharmacological management of patients undergoing total pancreatectomy with auto-islet transplantation

Chronic pancreatitis results in permanent parenchymal destruction of the pancreas gland leading to anatomical and physiological consequences for patients. Surgical management varies, and some patients require total pancreatectomy with autologous islet cell transplantation (TPIAT). Patients undergoing TPIAT require complex and diligent management after surgery. This encompasses the management of glucose control (endocrine function of the pancreas) and supplementing loss of exocrine function of the pancreas with digestive enzymes. Other areas of management include optimizing pain relief while reducing narcotic usage, providing antimicrobial prophylaxis, and reducing loss of islet cells by improving its integrity through anticoagulation and use of anti-inflammatory agents. Each aspect of care is unique to this population. However, comprehensive reviews on its pharmacological management are scarce. This review will discuss the available literature to date surrounding all aspects of pharmacological management of patients undergoing TPIAT.

Urinary 11-dehydrothromboxane B2 aspirin efficacy testing is sensitive to perioperative inflammation in pediatric solid-organ transplant patients

BACKGROUND

Evidence for aspirin efficacy testing in pediatrics is limited, especially outside of cardiology, yet thrombotic events have high morbidity in other areas such as pediatric transplant surgery. Debates about whether thromboembolic events while on aspirin represent "aspirin resistance" or "high on-treatment platelet reactivity" persist, given the poor intertest agreement between testing platforms.

PROCEDURE

This prospective observational study involved measuring aspirin efficacy using ex vivo testing of platelet aggregation (VerifyNow-Aspirin, VN) and urine 11-dehydrothromboxane B2 (AsprinWorks, UTxB2) contemporaneously at up to three time points after major noncardiac organ transplant surgery. The collection days (CD) were the second and seventh days after stable aspirin dosing and then a convalescent time point 2-9 months later.

RESULTS

Fifty-five participants (age range, 0-21 years) were enrolled, having undergone total pancreatectomy with islet autotransplantation (N = 36), orthotopic liver transplantation (N = 18), and combined liver-kidney transplantation (N = 1). Platelet reactivity measured by VN remained unchanged, whereas UTxB2, which was elevated postoperatively, decreased significantly from CD1 to CD2 and CD3. Discordance in therapeutic efficacy was noted per manufacturer cutoffs, with therapeutic VN results in 86% of tests, whereas 12% of UTxB2 were therapeutic. Age-based stratification of UTxB2 results using previously published pediatric median levels increased overall UTxB2 therapeutic rates (80%) and intertest concordance (67% vs 27% if using adult range). No thrombotic events were observed.

CONCLUSIONS

Our data suggest that urine thromboxane production may be an underappreciated reflection of postoperative inflammation. Validation of pediatric normal ranges for UTxB2 is a critical next step.

Portal Vein Thrombosis May Be More Strongly Associated With Islet Infusion Than Extreme Thrombocytosis After Total Pancreatectomy With Islet Autotransplantation

BACKGROUND

Total pancreatectomy with islet autotransplantation (TPIAT) involves pancreatectomy, splenectomy, and reinjection of the patient's pancreatic islets into the portal vein. This process triggers a local inflammatory reaction and increase in portal pressure, threatening islet survival and potentially causing portal vein thrombosis. Recent research has highlighted a high frequency of extreme thrombocytosis (platelets ≥1000 × 109/L) after TPIAT, but its cause and association with thrombotic risk remain unclear.

METHODS

This retrospective single-site study of a contemporary cohort of 409 pediatric and adult patients analyzed the frequency of thrombocytosis, risk factors for thrombosis, and antiplatelet and anticoagulation strategies.

RESULTS

Of 409 patients, 67% developed extreme thrombocytosis, peaking around postoperative day 16. Extreme thrombocytosis was significantly associated with infused islet volumes. Thromboembolic events occurred in 12.2% of patients, with portal vein thromboses occurring significantly earlier than peripheral thromboses. Portal vein thromboses were associated with infused islet volumes and portal pressures but not platelet counts or other measures. Most thromboembolic events (82.7%) occurred before the postoperative day of maximum platelet count. Only 4 of 27 (14.8%) of portal vein thromboses occurred at platelet counts ≥500 × 109/L. Perioperative heparin was given to all patients. Treatment of reactive thrombocytosis using aspirin in adults and hydroxyurea in children was not associated with significantly decreased thromboembolic risk.

CONCLUSIONS

These results suggest that post-TPIAT thrombocytosis and portal vein thromboses may be linked to the islet infusion inflammation, not directly to each other, and further reducing this inflammation may reduce thrombosis and thrombocytosis frequencies simultaneously.

Total Pancreatectomy with Autologous Islet Cell Transplantation-The Current Indications

Total pancreatectomy is a major complex surgical procedure involving removal of the whole pancreatic parenchyma and duodenum. It leads to lifelong pancreatic exocrine and endocrine insufficiency. The control of surgery-induced diabetes (type 3) requires insulin therapy. Total pancreatectomy with autologous islet transplantation (TPAIT) is performed in order to prevent postoperative diabetes and its serious complications. It is very important whether it is safe and beneficial for patients in terms of postoperative morbidity and mortality, and long-term results including quality of life. Small duct painful chronic pancreatitis (CP) is a primary indication for TPAIT, but currently the indications for this procedure have been extended. They also include hereditary/genetic pancreatitis (HGP), as well as less frequent indications such as benign/borderline pancreatic tumors (intraductal papillary neoplasms, neuroendocrine neoplasms) and “high-risk pancreatic stump”. The use of TPAIT in malignant pancreatic and peripancreatic neoplasms has been reported in the worldwide literature but currently is not a standard but rather a controversial management in these patients. In this review, history, technique, indications, and contraindications, as well as short-term and long-term results of TPAIT, including pediatric patients, are described.

Inaccurate Glucose Sensor Values After Hydroxyurea Administration

Objective: To assess the degree, duration, mean absolute relative difference (MARD), and error analysis of discrepant values per continuous glucose monitoring (CGM) systems after hydroxyurea (HU) administration. Research Design and Methods: Inpatient glucometer and CGM data from 16 total pancreatectomy/islet autotransplantation patients using Dexcom Professional G4 and 12 patients using Dexcom G6 were analyzed after daily dosing with HU. Timing of HU dosing and median of 9.5 days of sensor and glucometer values were assessed per patient. Results: A large positive elevation of sensor readings was identified after HU dosing. The greatest discrepancy between glucometer and sensor readings occurred 0.5-2 h after HU administration [G4 (mean 3.0 mmol/L, median 2.4 mmol/L, MARD 55%), G6 (mean 4.2 mmol/L, median 4.6 mmol/L, MARD 91%)]. The discrepancy was <1.1 mmol/L, mean (-0.5 mmol/L) and median (-0.5 mmol/L), MARD 14% (G4) and <1.1 mmol/L, mean (0.3 mmol/L) and median (0.3 mmol/L), MARD 17% (G6), by 6 h after administration. Error analysis with the G6 system found 94% of pairs in clinically acceptable range by 6-9 h after HU administration. Aspirin, also given once daily, did not result in glucose value discrepancy with the G6 system but variability was observed with the G4 system. Conclusions: There was marked elevation of sensor glucose readings compared with glucometer values [up to 13.9 mmol/L (G4), 13 mmol/L (G6)] from 0.5 to 6 h after HU administration. It is important to counsel a patient using a Dexcom CGM system and HU therapy on this finding and to advise reliance on glucometer testing for accurate glucose assessment up to 6-9 h after HU administration.

Improved Glycemic Outcomes with Early Initiation of Insulin Pump Therapy in Pediatric Postoperative Total Pancreatectomy with Islet Autotransplantation

Total pancreatectomy with islet autotransplantation (TPIAT) is a surgical procedure for patients with chronic pancreatitis and poor quality of life. Euglycemia is critical for islet cell survival and engraftment. We reviewed clinical care practice and hypothesized that early in-hospital transition from intravenous insulin to insulin pump therapy, managed by an endocrine unit trained on post-surgical care, would improve glucose control and impact the length of hospital stay. We completed a retrospective analysis of 40 pediatric patients who underwent TPIAT. Comparative hospitalized postoperative groups included those who received insulin intravenously, followed by multiple daily injections, subsequently managed by pump therapy (n = 14), versus those who received insulin intravenously followed by early pump therapy provided on the endocrine unit trained to manage post-surgical patients (n = 26). The outcomes analyzed included percentage of blood glucoses in target (4.44–6.66 mmol/L (80–120 mg/dL)), hypoglycemia (<3.33 mmol/L (<60 mg/dL)) and hyperglycemia (>7.77 mmol/L (>140 mg/dL)), blood glucose variability, and length of hospital unit stay post-ICU. Hospitalized patients with early transition to pump therapy on a specialized endocrine unit had a higher proportion of glucose values in the target range (61% vs. 51%, p = 0.0003), a lower proportion of hyperglycemia (15% vs. 19%, p = 0.04), and a lower proportion of hypoglycemia, though not statistically significant (3.4% vs. 4.4%, p = 0.33). Early pump users also had lower variability in glucose values over 10 days post-intravenous insulin (p = 0.001), and the post-transition median length of stay was shorter by 5 days (median: 11.5 vs. 16.5 days, p = 0.005). Early in-hospital pump therapy managed by the specialized endocrine unit improved glucose outcomes and reduced the duration of in-unit stay.

Hydroxyurea Pharmacokinetics in Pediatric Patients After Total Pancreatectomy With Islet Autotransplantation

Total pancreatectomy with islet autotransplantation is a complex surgical approach for acute recurrent or chronic pancreatitis that frequently triggers extreme thrombocytosis (platelets ≥ 1000 × 10⁹ /L). Thrombocytosis can be prothrombotic, so cytoreductive hydroxyurea is often initiated after this surgery; however, optimal dosing strategy and efficacy are unknown. This prospective pilot study characterized the pharmacokinetics of hydroxyurea after this procedure in children. It also compared them with previously published pediatric parameters in sickle cell anemia (SCA), the disease in which pediatric hydroxyurea pharmacokinetics have primarily been studied. Plasma hydroxyurea levels were quantified in 14 participants aged 4-19 years using high-performance liquid chromatography. Blood collections were scheduled 20 minutes, 1 hour, and 4 hours after the first dose, on pharmacokinetic day 1 (PK1), and again 2-3 months later if still on hydroxyurea (PK2). Six participants had PK1 and PK2 data at all 3 postdose timed collections, 5 only had PK1 samples, and 3 only had PK2 samples. Total pancreatectomy with islet autotransplantation participants had reduced and delayed absorption compared with sickle cell anemia participant data from the Hydroxyurea Study of Long-Term Effects, regardless of timing or dosing methodology. Total pancreatectomy with islet autotransplantation participants had different pharmacokinetic profiles at PK1 versus PK2, with lower dose-normalized exposures than previously reported in sickle cell anemia. These results suggest variability exists in hydroxyurea absorption and bioavailability in total pancreatectomy with islet autotransplantation patients, suspected to be primarily because of Roux-en-Y reconstruction, and suggest that more pharmacokinetic data are needed for scenarios when hydroxyurea is prescribed to children without sickle cell anemia.