Impact of peri-operative red blood cell transfusions for treatment of anemia on acute rejection in renal transplant recipients.

INTRODUCTION: Anemia occurs before and after kidney transplantation. Determining the impact of perioperative transfusion on post-transplant outcomes can help determine best management of anemia. PROJECT AIM: The current study aims to describe clinical outcomes associated with packed red blood cell transfusions in the peri-operative management of anemia after transplantation. DESIGN: This was a single-center, retrospective study of adult kidney recipients with anemia at the time of transplantation. 1271 patients were stratified by donor-type due to the potential variability in underlying recipient and transplant characteristics; living donor (n = 698, 62%) or deceased donor (n = 573, 38%). RESULTS: Living donor recipients that received blood during the index hospitalization were more likely to experience rejection within 30 days (18% vs. 10%, p = 0.008) and 1 year of transplant (32% vs. 16%, p = 0.038). In multivariate analysis, receiving both blood and darbepoetin (HR: 1.89 [1.20,3.00], p = 0.006), age at transplant (HR: 0.98 [0.97, 0.99], p = 0.02), number of HLA mismatches (HR: 1.17 [1.05,1.30], p = 0.003), and whether the case was a repeat transplant (HR: 2.77 [1.93,3.97], p < 0.01) were significantly associated with hazard of rejection. For deceased donor recipients, there were no differences in acute rejection, graft failure or mortality at 30 days or 1 year. When analyzing hazard of rejection in a multivariate model, treatment received was not found to be significantly associated with rejection. CONCLUSION: Our findings suggest there may be a role for more aggressive pre-transplant treatment of anemia for those patients undergoing living donor transplants.

Obesity is associated with a higher incidence of rejection in patients on belatacept: A pooled analysis from the BENEFIT/BENEFIT-EXT clinical trials.

Though belatacept is administered with a weight-based dosing schema, there has been higher clearance reported in obese patients. Therefore, we evaluated the association between body mass index (BMI) and transplant outcomes in kidney transplant recipients who were randomized to cyclosporine- or belatacept-based immunosuppression in the BENEFIT and BENEFIT-EXT randomized clinical trials. A total of 666 and 543 patients underwent randomization and transplantation in BENEFIT and BENEFIT-EXT, respectively, of which 1056 had complete data and were included in this analysis. Patients were grouped categorically according to BMI: <25, 25 to <30, and ≥30 kg/m2. BMI did influence both the incidence and severity of acute rejection. Obese patients with BMI >30 kg/m2 in the low intensity belatacept group experienced significantly more rejection at 12 months than did patients with BMI <25 kg/m2 or BMI 25 to <30 kg/m2. In both the moderate intensity belatacept and low intensity belatacept groups, obese patients with BMI >30 kg/m2 experienced significantly more severe acute rejection than did patients with BMI < 25 kg/m2 or BMI 25 to <30 kg/m2. These results suggest that obese kidney transplant recipients are at an increased risk for acute rejection when under belatacept-based immunosuppression when compared to nonobese patients.

Bivalirudin Compared to Heparin as the Primary Anticoagulant in Pediatric Berlin Heart Recipients.

Bivalirudin has been used in increasing frequency as an alternative to unfractionated heparin (UFH) in pediatric recipients of Berlin Heart EXCOR ventricular assist devices (VAD). This single-center, retrospective review characterizes anticoagulant trends and outcomes in pediatric Berlin Heart VAD recipients implanted between September 1, 2013, and August 31, 2021, anticoagulated with either bivalirudin or UFH. Thirty-one patients were included; 65% who received bivalirudin and 35% who received UFH. The median age was 2.9 years, included 64.5% females, with 61.3% of patients diagnosed with dilated cardiomyopathy and 25.8% of patients with congenital heart disease. Therapeutic anticoagulation was achieved sooner in the bivalirudin group compared to UFH via anti-Xa monitoring (median 5.7 and 69.5 hours, respectively, p < 0.001). Bivalirudin had a greater number of therapeutic values comparatively to UFH (52% and 24%, respectively; p < 0.001) and a superior number of hours in the therapeutic range (67% and 32%, respectively; p < 0.001). Secondary outcomes were similar among the two groups, apart from greater chest tube output (UFH), more frequent events of elevated plasma-free hemoglobin (bivalirudin), and more frequent elevated inflammatory markers postimplant (bivalirudin). Prevalence of pump replacements secondary to significant clot burden and prevalence of stroke was comparable. In this patient cohort, bivalirudin demonstrated greater anticoagulation stability comparatively to UFH. Multicenter collaboration would be necessary to identify whether this further translates into improved patient outcomes.

Immune cell function assay and T lymphocyte counts lack association with rejection or infection in pediatric heart transplant recipients.

INTRODUCTION: Immune cell function assay (ICFA) and CD3 lymphocyte counts have been considered to be useful in discerning the overall intensity of immunosuppression in pediatric orthotopic heart transplant (OHT) recipients. METHODS: The aim of this retrospective analysis was to evaluate trends of ICFA and CD3 lymphocyte counts and their association with adverse outcomes post-OHT. RESULTS: A total of 381 ICFA and 493 CD3 laboratory values obtained in 78 patients within six months post-OHT were analyzed. There were 14 patients treated for biopsy-proven acute rejection, four of whom had ISHLT grade 2R/3A rejection. In patients with rejection versus those without, CD3 and ICFA values were 122 (IQR 74.5-308) cells/mm2 and 224.5 (IQR 132-343.5) ng/ml compared to 231.8 (IQR 68-421) cells/m2 and 191 (IQR 81.5-333) ng/mL (p = NS for both). Twenty-six patients had at least one detectable cytomegalovirus or Epstein-Barr virus DNAemia within the study timeframe. In patients with viremia versus those without, CD3 and ICFA values were 278.5 (IQR 68-552) cells/mm2 and 130 (IQR 48-284) ng/ml compared to 195 (IQR 74.5-402.5) cells/mm2 and 212 (IQR 89-342) ng/ml (p = NS for both). CONCLUSIONS: No association was found between these immune markers and adverse outcomes. In the absence of larger pediatric studies justifying the role of these tests in identifying elevated risk profiles post OHT, we do not recommend their routine use.

Elevated posaconazole trough concentrations are not associated with increased risk for posaconazole toxicity in lung transplant recipients.

OBJECTIVE: Posaconazole is used for prophylaxis and treatment of invasive fungal infections in lung transplant recipients (LTR). Previous studies have not described the relationship between elevated posaconazole trough concentrations and adverse drug reactions in this population. METHODS: This IRB-approved, retrospective cohort study at NewYork-Presbyterian Hospital included LTR who had posaconazole trough concentrations measured. The primary aim of this study was to evaluate elevated posaconazole trough concentrations and changes in liver function tests as well as QTc interval. A secondary aim of this study was to identify patient factors associated with elevated posaconazole trough levels. RESULTS: A total of 109 LTR were included. The average age was 58.1 years (IQR, 48-65), the majority were male (56%). A total of 932 trough levels were assessed with a median number of 8 (IQR, 5-15) levels per patient. The median posaconazole trough concentration was 1.7 mg/L (IQR, 1.1-2.5). Hepatotoxicity, as defined by common terminology criteria for adverse events (CTCAE), was observed in 73.4% of subjects, with the majority classified as grade 1 (67.5%). However, there was no correlation between elevated posaconazole levels and aspartate aminotransferase (r = .03), alanine aminotransferase (r = .04), alkaline phosphatase (r = .04), and total bilirubin (r = .02). There was also no correlation between posaconazole trough concentrations and QTc interval (r = .03). CONCLUSION: This analysis demonstrates that no correlation exists between whole blood posaconazole levels and hepatotoxicity or QTc prolongation. Based on these results, posaconazole dose reductions may not be warranted for posaconazole levels that are significantly above the therapeutic target to avert risk for hepatotoxicity or QTc prolongation.

COVID-19 therapeutics and outcomes among solid organ transplant recipients during the Omicron BA.1 era.

Treatment outcomes associated with the use of novel COVID-19 therapeutics in solid organ transplant recipients (SOTR) are not well described in the literature. The objective of this analysis was to characterize 30-day hospitalization and other key secondary endpoints experienced by outpatient SOTR with mild-moderate COVID-19 treated with nirmatrelvir/ritonavir (NR), sotrovimab, or no SARS-CoV-2 specific treatment. This IRB-approved, retrospective study included 154 SOTR with a documented positive SARS-CoV-2 infection between December 16, 2021 and January 19, 2022 (a predominant Omicron BA.1 period in New York City). Patients who received NR (N = 28) or sotrovimab (N = 51) experienced a lower rate of 30-day hospitalization or death as compared to those who received no specific treatment (N = 75) (p = .009). A total of three deaths occurred, all among patients who initially received no specific treatment prior to hospitalization. These results suggest a role for SARS-CoV-2 specific agents in the treatment of SOTR with COVID-19, and that there does not appear to be any difference in effectiveness when comparing NR versus sotrovimab.

Early clinical experience with nirmatrelvir/ritonavir for the treatment of COVID-19 in solid organ transplant recipients.

Nirmatrelvir/ritonavir (NR) use has not yet been described in solid organ transplant recipients (SOTRs) with mild COVID-19. The objective was to evaluate outcomes among SOTR and describe the drug-drug interaction of NR. This is an IRB-approved, retrospective study of all adult SOTR on a calcineurin inhibitor (CNI) or mammalian target of rapamycin inhibitor who were prescribed NR between December 28, 2021 and January 6, 2022. A total of 25 adult SOTR were included (n = 21 tacrolimus, n = 4 cyclosporine, n = 3 everolimus, n = 1 sirolimus). All patients were instructed to follow the following standardized protocol during treatment with 5 days of NR: hold tacrolimus or mTOR inhibitor or reduce cyclosporine dose to 20% of baseline daily dose. Four patients (16%) were hospitalized by day 30; one for infectious diarrhea and three for symptoms related to COVID-19. No patients died within 30 days of receipt of NR. Median tacrolimus level pre- and post-NR were 7.4 ng/ml (IQR, 6.6-8.6) and 5.2 (IQR, 3.6-8.7), respectively. Four patients experienced a supratherapeutic tacrolimus concentration after restarting tacrolimus post-NR. Our results show the clinically significant interaction between NR and immunosuppressive agents can be reasonably managed with a standardized dosing protocol. Prescribers should carefully re-introduce CNI after the NR course is complete.

Comparing weight-based dosing of tacrolimus XR in obese and non-obese renal transplant recipients.

The recommended initial weight-based dose of extended-release (XR) tacrolimus (Envarsus XR) in kidney transplant recipients (KTR) is 0.14 mg/kg/day. However, no data exist regarding dosing recommendations for obese patients specifically. The aim of this study was to evaluate weight-based dosing requirements in a cohort of obese KTR who were initiated on de novo tacrolimus XR post-transplantation. The primary outcome was weight-based dosing requirements (mg/kg/day) on post-operative day (POD) 7 and 14. Of the 254 KTR, 81 (31%) were obese. The median therapeutic dose on POD7 was 0.1 versus 0.12 vs. 0.14 mg/kg/day in the BMI > 30 kg/m2 , BMI 25-30 kg/m2 , and BMI < 25 kg/m2 , respectively, (p = .0001). This result was similar on POD14; median therapeutic dose was 0.09 versus 0.11 versus 0.15 mg/kg/day in the BMI > 30 kg/m2 , BMI 25-30 kg/m2 , and BMI < 25 kg/m2 , respectively, (p < .001). Therapeutic dose on POD7 and POD14 based on ideal body was similar in all cohorts (p = .238, p = .923, respectively). This finding was supported by a strong linear relationship between ideal body weight (IBW) and therapeutic dose (r = .929). In both obese and non-obese KTR, IBW had a stronger correlation with the therapeutic dose for tacrolimus XR.

Less bleeding associated with apixaban versus other direct acting oral anticoagulation in solid organ transplant recipients.

BACKGROUND: The purpose of this study was to evaluate outcomes of bleeding and thrombosis resulting from the use of direct oral anticoagulants (DOACs) in a large cohort of solid organ transplant (SOT) recipients. METHODS: This was a single center, retrospective cohort study of adult kidney, heart, lung, and liver transplant recipients transplanted between August 2009 and May 2018. Patients were stratified into two groups: those who received apixaban (apixaban group) or those patients receiving either rivaroxaban or dabigatran (non-apixaban group). The primary endpoint was the cumulative incidence of bleeding while receiving DOAC therapy. The secondary endpoints were incidence of major bleeding and thrombosis at any time while receiving DOAC therapy. RESULTS: A total of 106 patients were included; 70 patients received apixaban and 36 patients received non-apixaban anticoagulation. Cumulative incidence of any bleeding was lower in the apixaban group compared to the non-apixaban group at both 90 days (4.9% vs. 16.1%) and 180 days (11.4% vs. 24.9%, P = .034). Cumulative incidence of major bleeding (P = .686) and thrombosis (P = .515) were similar between groups. DOAC dosing congruent with the package insert(s) was associated with a lower risk of thrombosis. CONCLUSION: Apixaban-based anticoagulation was associated with a lower cumulative incidence of any bleeding compared to non-apixaban DOACs.