Direct oral anticoagulant considerations in solid organ transplantation: A review

Exploring safety and efficacy of rivaroxaban after living donor liver transplantation: a retrospective study

PURPOSE

Thromboembolic complications remain a significant concern in postoperative patients, particularly those who have undergone liver transplantation. Warfarin has been the standard oral anticoagulant. Direct oral anticoagulants (DOACs) have several advantages over warfarin, including rapid onset of action and standardized dose guidelines. We aimed to assess the safety of rivaroxaban in living donor liver transplantation (LDLT) recipients.

METHODS

This study was a single-center, retrospective descriptive analysis of LDLT recipients who received rivaroxaban between December 2020 and April 2022. A total of 27 recipients received rivaroxaban postoperatively. Liver function tests, immunosuppression levels, serum creatinine, and INR were recorded before the initiation of rivaroxaban and then on post-therapy days 1, 7, 14, 28, 90, and 180.

RESULTS

Among the 27 recipients receiving rivaroxaban postoperatively, portal venous thrombosis was the most prevalent indication for anticoagulation (44.4%), followed by Budd-Chiari syndrome (29.6%). Nine patients had a twofold increase in either ALT or AST values, two of whom were treated for biliary strictures and the others for rejection. Eighteen patients were given tacrolimus, and eight were on cyclosporine, with one patient switched from tacrolimus to cyclosporine due to insufficient therapeutic levels. There were no incidents of bleeding or re-thrombosis during the 180-day follow-up period.

CONCLUSION

Rivaroxaban may be a safe and effective alternative in LDLT recipients with no significant adverse incidents. Further studies with larger sample sizes are needed to confirm these findings and determine this population's optimal dose and duration of rivaroxaban therapy.

Oral Anticoagulants after Heart Transplantation-Comparison between Vitamin K Antagonists and Direct Oral Anticoagulants

AIMS

Patients after heart transplantation (HTX) often require oral anticoagulants (OACs) due to atrial arrhythmias or thromboembolic events but little is known about the post-transplant use of direct oral anticoagulants (DOACs). We investigated the frequency, indications, and complications of DOACs and vitamin K antagonists (VKAs) after HTX.

METHODS

We screened all adult patients for the use of post-transplant OACs who underwent HTX at Heidelberg Heart Center between 2000 and 2021. Patients were stratified by type of OAC (DOAC or VKA) and by DOAC agents (apixaban, dabigatran, edoxaban, or rivaroxaban). Indications for OACs comprised atrial fibrillation, atrial flutter, pulmonary embolism, upper and lower extremity deep vein thrombosis, as well as intracardiac thrombus.

RESULTS

A total of 115 of 459 HTX recipients (25.1%) required OACs, including 60 patients with DOACs (52.2%) and 55 patients with VKAs (47.8%). Concerning DOACs, 28 patients were treated with rivaroxaban (46.7%), 27 patients with apixaban (45.0%), and 5 patients with edoxaban (8.3%). We found no significant differences between both groups concerning demographics, immunosuppressive drugs, concomitant medications, indications for OACs, ischemic stroke, thromboembolic events, or OAC-related death. Patients with DOACs after HTX had a significantly lower one-year rate of overall bleeding complications (p = 0.002) and a significantly lower one-year rate of gastrointestinal hemorrhage (p = 0.011) compared to patients with VKAs after HTX in the Kaplan-Meier estimator.

CONCLUSIONS

DOACs were comparable to VKAs concerning the risk of ischemic stroke, thromboembolic events, or OAC-related death but were associated with significantly fewer bleeding complications in HTX recipients.

Youngest en-bloc kidney transplant recipient in India: defying the barriers and challenges with teamwork

We received a call from a transplant coordinator about the availability of a consented deceased donor. En-bloc kidneys with the aorta and IVC (inferior vena cava) were harvested from a toddler weighing 8 kg. The recipient was of early childhood weighing 14 kg who had been on haemodialysis for the last 3 years for end-stage kidney disease. He received anti-thymocyte globulin as an induction immunosuppressant. The kidneys were transplanted en bloc in the right lower quadrant retroperitoneal region; an anastomosis was performed to the recipient's aorta and IVC, and two separate neocystoureterostomies were created. His serum creatinine reached 0.5 mg/dL on the seventh postoperative day, following a few days of delayed graft function. In this study, we describe the surgical and non-surgical challenges that we faced while performing en-bloc kidney transplant to the youngest recipient and how a multidisciplinary team approach helped us overcome them.

Descriptive analysis evaluating the use of direct oral anticoagulation therapy in heart and lung transplant recipients

BACKGROUND

Direct oral anticoagulants (DOACs) are widely utilized following cardiothoracic transplantation with limited guidance regarding drug-drug interactions (DDIs), periprocedural management, and DOAC-specific monitoring.

METHODS

We performed a single-center, retrospective, descriptive analysis of adult cardiothoracic transplant recipients initiated on DOAC therapy between May 2016 and July 2021. The primary endpoint for this analysis was the percentage of patients dosed per package labeling. Secondary endpoints included DOAC prescribing in the context of DDIs, renal dysfunction, and periprocedural management, as well as thromboembolism and major bleeding at 12 months.

RESULTS

A total of 125 patients were included in this analysis with a median age of 62 years. At initiation, 63.2% of patients were dosed according to package labeling. The most common reason for non-labeled dosing was concomitant azole antifungal therapy. DOAC therapy was held for 82 procedures with no reported thrombotic events and one major bleed in the setting of AKI. Hemodialysis-dependence was associated with a reduced risk of thrombosis (0 vs. 10 events per 100 PY, p = .002) and an increased risk of major bleeding (23 vs. 8 events per 100 PY, p = .006). Additionally, DOAC-specific anti-xa guided dosing was associated with a reduced risk of major bleeding (0 vs. 13 events per 100 PY, p < .001).

CONCLUSION

Our findings show that deviation from package labeling is common following cardiothoracic transplantation and its association with clinical outcomes warrants further study.

Safety and mortality outcomes for direct oral anticoagulants in renal transplant recipients

PURPOSE

Direct oral anticoagulants (DOACs) are increasingly used in renal transplant recipients (RTR), but relatively understudied in this population. We assess the safety of post-transplant anticoagulation with DOACs compared to warfarin.

METHODS

We conducted a retrospective study of RTRs at the Mayo Clinic sites (2011-present) that were anticoagulated for greater than 3 months excluding the 1st month post-transplant. The main safety outcomes were bleeding and all-cause mortality. Concomitant antiplatelet and interacting drugs were noted. DOAC dose adjustment was assessed according to common US prescribing practices, guidelines, and/or FDA labeling.

RESULTS

The median follow-up was longer for RTRs on warfarin (1098 days [IQR 521, 1517]) than DOACs (449 days [IQR 338, 942]). Largely, there were no differences in baseline characteristics and comorbidities between RTRs on DOACs (n = 208; apixaban 91.3%, rivaroxaban 8.7%) versus warfarin (n = 320). There was no difference in post-transplant use of antiplatelets, immunosuppressants, most antifungals assessed, or amiodarone. There was no significant difference in incident major bleeding (8.4 vs. 5.3%, p = 0.89), GI bleeding (4.4% vs. 1.9%, p = 0.98), or intra-cranial hemorrhage (1.9% vs. 1.4%, p = 0.85) between warfarin and DOAC. There was no significant difference in mortality in the warfarin group compared to DOACs when adjusted for follow-up time (22.2% vs. 10.1%, p = 0.21). Rates of post-transplant venous thromboembolism, atrial fibrillation or stroke were similar between the two groups. 32% (n = 67) of patients on DOACs were dose reduced, where 51% of those reductions were warranted. 7% of patients that were not dose reduced should have been.

CONCLUSIONS

DOACs did not have inferior bleeding or mortality outcomes compared to warfarin in RTRs. There was greater use of warfarin compared to DOACs and a high rate of improper DOAC dose reduction.

Safety of Non-Vitamin K Antagonist Oral Anticoagulant Treatment in Patients with Chronic Kidney Disease and Kidney Transplant Recipients

The use of novel oral anticoagulants in patients with impaired renal function or undergoing immunosuppressive therapy is limited due to the risk of drug-to-drug interactions and anticoagulation-related adverse events. This article aims to assess the current data on the safety of direct-acting oral anticoagulant-based therapy in the population of kidney transplant recipients and patients with impaired renal function. The most important factors affecting the safety of treatment are the incidence of bleeding events, thromboembolic events, deaths and drug-to-drug interactions. The available data were compared to the findings on warfarin-based anticoagulation. Findings on the use of novel oral anticoagulants in kidney transplant recipients are limited yet promising in terms of safety and efficacy of use. However, current recommendations state that the co-administration of non-vitamin K antagonist oral anticoagulants with several immunosuppressive agents is contraindicated.

Drug Interactions Affecting Oral Anticoagulant Use

Oral anticoagulants (OACs) are medications commonly used in patients with atrial fibrillation and other cardiovascular conditions. Both warfarin and direct oral anticoagulants are susceptible to drug-drug interactions (DDIs). DDIs are an important cause of adverse drug reactions and exact a large toll on the health care system. DDI for warfarin mainly involve moderate to strong inhibitors/inducers of cytochrome P450 (CYP) 2C9, which is responsible for the elimination of the more potent S-isomer of warfarin. However, inhibitor/inducers of CYP3A4 and CYP1A2 may also cause DDI with warfarin. Recognition of these precipitating agents along with increased frequency of monitoring when these agents are initiated or discontinued will minimize the impact of warfarin DDI. Direct oral anticoagulants are mainly affected by medications strongly affecting the permeability glycoprotein (P-gp), and to a lesser extent, strong CYP3A4 inhibitors/inducers. Dabigatran and edoxaban are affected by P-gp modulation. Strong inducers of CYP3A4 or P-gp should be avoided in all patients taking direct oral anticoagulant unless previously proven to be otherwise safe. Simultaneous strong CYP3A4 and P-gp inhibitors should be avoided in patients taking apixaban and rivaroxaban. Concomitant antiplatelet/anticoagulant use confers additive risk for bleeding, but their combination is unavoidable in many cases. Minimizing duration of concomitant anticoagulant/antiplatelet therapy as indicated by evidence-based clinical guidelines is the best way to reduce the risk of bleeding.

Case Report of a Patient Treated With Acenocumarol Awaiting Orthotopic Liver Transplant: Perioperative Coagulation Management and Risk for Hepatic Artery Thrombosis

BACKGROUND

End-stage liver disease is associated with a concomitant reduction of pro- and anticoagulant factors that typically leads to rebalanced hemostasis. This rebalanced hemostasis can be easily disturbed, encountering both hemostasis-related bleeding episodes and thrombotic events.

METHODS

This article reports a case of a 52-year-old man diagnosed with portal vein thrombosis and treated with Acenocumarol. The patient received ortothopic liver transplant. The preprocedure international normalized ratio was 3.5. A transfusion of 2000 units of prothrombin complex concentrate was indicated by Hematology.

RESULTS

Repeated intra- and postoperative hepatic artery thrombosis resulted in graft loss and patient retransplantation in first 24 hours.

CONCLUSIONS

The new concept of rebalanced hemostasis in these patients forces us to change our clinical decisions in preoperative coagulation management, avoiding old practices based on the traditional model such as transfusion guided by international normalized ratio and platelet count, among others that will be analyzed in present work.

Safety and efficacy of direct oral anticoagulants under long-term immunosuppressive therapy after liver, kidney and pancreas transplantation

The safety of direct oral anticoagulants (DOACs) in patients after solid organ transplantation (SOT) is not well defined. This study aimed at describing the safety and efficacy of DOACs in patients after SOT. Patients after kidney and/or liver transplantation under maintenance immunosuppression treated with rivaroxaban (n = 26), apixaban (n = 20) and edoxaban (n = 1) were included. Clinical data were collected retrospectively and using a questionnaire. DOAC plasma levels and thrombin generation (TG) were measured in patients after SOT and compared with nontransplanted controls receiving DOACs. DOACs were administered for 84.6 patient-years. Mean immunosuppressive trough levels after DOAC initiation increased from baseline by 18.8 ± 29.6% compared to 3.0 ± 16.5% in matched controls (P = 0.004), without significant differences in dose adjustments. No transplant rejection or significant change in liver or renal function was observed. There was one major bleeding after the observation period but no thromboembolic complication. DOAC plasma levels reached the expected range in all patients. The intrinsic hemostatic activity in transplanted patients was higher compared to nontransplant controls. Treatment with DOACs after SOT is safe and effective. Immunosuppressive trough levels should be monitored after DOAC initiation, particularly in the early phase after SOT. These data should be confirmed in a prospective study.

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 DOACs in a large cohort of 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% versus 16.1%) and 180 days (11.4% versus 24.9%, P = 0.034). Cumulative incidence of major bleeding (P = 0.686) and thrombosis (P = 0.515) 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. This article is protected by copyright. All rights reserved.

Clinical Evidence for the Choice of the Direct Oral Anticoagulant in Patients with Atrial Fibrillation According to Creatinine Clearance

Atrial fibrillation (AF) often coexists with chronic kidney disease (CKD), which confer to the patient a higher risk of both thromboembolic and hemorrhagic events. Oral anticoagulation therapy, nowadays preferably with direct oral anticoagulants (DOACs), represents the cornerstone for ischemic stroke prevention in high-risk patients. However, all four available DOACs (dabigatran, apixaban, rivaroxaban and edoxaban) are eliminated by the kidneys to some extent. Reduced kidney function facilitates DOACs accumulation and, therefore, different dose reductions are required, with slight differences between American and European recommendations especially in case of severe renal impairment (creatinine clearance < 30 mL/min). Overall, the use of DOACs in patients with non-end stage CKD and AF is effective similarly to warfarin, showing a better safety profile. The management of thromboembolic risk among patients with AF on dialysis remains challenging, as warfarin effectiveness for stroke prevention in this population is questionable and retrospective data on apixaban need to be confirmed on a larger scale. In kidney transplant recipients, DOACs may provide a potentially safer option compared to warfarin, but co-administration with immunosuppressants is a matter of concern.

Need for anticoagulation and use of direct oral anticoagulants in lung transplant recipients

Limited information is available about use of direct oral anticoagulants (DOACs) in lung transplant recipients (LTRs). The purpose of this study is to describe the indications and use of long-term anticoagulation, including the safety and tolerability of DOACs, in LTRs. This was a single-center retrospective study. LTRs who received therapeutic anticoagulation were identified. Patient characteristics, indications for treatment, and complications of therapy were obtained. A total of 203 patients underwent lung transplantation of which 118 patients (58.1%) had an indication for anticoagulation. Patients with an indication for anticoagulation were older than those without (59 ± 14 years versus 48 ± 17 years, p < 0.001) and were more likely to be male (72.0% versus 50.6%, p = 0.002). Of the patients with indication for anticoagulation, 74 (62.7%) received it. Fifty-one (68.9%) of patients receiving anticoagulation were treated with DOACs. In the patients receiving anticoagulation, there were 14 major bleeding events in 13 patients, of which 3 were receiving DOACs and the remainder were receiving heparin or warfarin. The need for anticoagulation is common in LTRs for both atrial arrhythmias and venous thromboembolism. However, many patients with atrial arrhythmias do not receive anticoagulation. The use of DOACs is well tolerated and safe in LTRs.

The Impact of Dabigatran Treatment on Sinusoidal Protection Against Hepatic Ischemia/Reperfusion Injury in Mice

Thrombin is a key player in the coagulation cascade, and it is attracting much attention as a promotor of cellular injured signaling. In ischemia/reperfusion injury (IRI), which is a severe complication of liver transplantation, thrombin may also promote tissue damage. The aim of this study is to reveal whether dabigatran, a direct thrombin inhibitor, can attenuate hepatic IRI with focusing on a protection of sinusoidal endothelial cells (SECs). Both clinical patients who underwent hepatectomy and in vivo mice model of 60-minute hepatic partial-warm IRII, thrombin generation was evaluated before and after IRI. In next study, IRI mice were treated with or without dabigatran. In addition, hepatic SECs and hepatocytes pretreated with or without dabigatran were incubated in hypoxia/reoxygenation (H-R) environment in vitro. Thrombin generation evaluated by thrombin-antithrombin complex (TAT) was significantly enhanced after IRI in the clinical study and in vivo study. Thrombin exacerbated lactate dehydrogenase cytotoxicity levels in a dose-dependent manner in vitro. In an IRI model of mice, dabigatran treatment significantly improved liver histological damage, induced sinusoidal protection, and provided both antiapoptotic and anti-inflammatory effects. Furthermore, dabigatran not only enhanced endogenous thrombomodulin (TM) but also reduced excessive serum high-mobility group box-1 (HMGB-1). In H-R models of SECs, not hepatocytes, pretreatment with dabigatran markedly attenuated H-R damage, enhanced TM expression in cell lysate, and decreased extracellular HMGB-1. The supernatant of SECs pretreated with dabigatran protected hepatocytes from H-R damage and cellular death. Thrombin exacerbated hepatic IRI, and excessive extracellular HMGB-1 caused severe inflammation-induced and apoptosis-induced liver damage. In this situation, dabigatran treatment improved vascular integrity via sinusoidal protection and degraded HMGB-1 by endogenous TM enhancement on SECs, greatly ameliorating hepatic IRI.

Idarucizumab (Praxbind®) for dabigatran reversal in patients undergoing heart transplantation: a cohort of ten patients

Background

Novel oral anticoagulants are used in atrial fibrillation. Idarucizumab has been approved for reversal of dabigatran in situations of life-threatening hemorrhage or emergency surgery.

Objectives

We report a single center experience of ten patients on dabigatran therapy who were given idarucizumab prior to heart transplantation.

Methods & results

The mean plasma concentration of dabigatran prior to reversal was 139 ± 89 ng/ml. Hemoglobin, hematocrit and platelet levels were decreased after surgery. Surgical procedures were successfully performed with no increased risk, especially regarding bleeding complications. All patients were alive after 90 days.

Conclusion

Dabigatran reversal with idarucizumab in contexts of emergency surgery/urgent procedures is an attractive and safe option to be taken into consideration for patients with end stage heart disease awaiting transplantation and indication of anticoagulant therapy.

Survival Benefit of En Bloc Transplantation of Small Pediatric Kidneys in Children

BACKGROUND

En bloc transplantation of small pediatric kidneys in children may help expand the existing deceased donor pool; however, studies examining the long-term outcomes of en bloc transplantation in children are few.

METHODS

We used the Scientific Registry of Transplant Recipients to identify 149 pediatric en bloc recipients transplanted from October 1, 1987 to December 31, 2017. We used propensity scores to match 148 en bloc with 581 non-en bloc deceased donor recipients (matching variables: transplant age, gender, race, pretransplant dialysis, transplant center, and year). We evaluated patient and graft survival using Kaplan-Meier and Fleming-Harrington weighted log-rank test and examined survival benefit of en bloc transplantation versus remaining on the waiting list using the sequential Cox approach. We divided the study period into three 10-y intervals to assess the effect of era on outcomes.

RESULTS

Compared with non-en bloc recipients, en bloc recipients had lower 1-y graft survival (78.9% versus 88.9%; P = 0.007); however, when stratified by transplant era, lower 1-y survival was only observed in the oldest era (1987-1997). En bloc recipients had superior 10-y patient (89.0% versus 80.4%; P = 0.04) and graft survival (51.6% versus 39.9%; P = 0.04) compared with non-en bloc recipients. After multivariate adjustment, en bloc transplantation was associated with superior patient survival compared with remaining on the waiting list (adjusted hazard ratio: 0.58; 95% confidence interval: 0.36-0.95; P = 0.03).

CONCLUSIONS

En bloc transplantation of small pediatric kidneys in children is associated with superior long-term patient and graft survival. The increased risk of 1-y graft loss among en bloc recipients only appeared in the oldest era.

Use of direct-acting oral anticoagulants in solid organ transplantation: A systematic review

The use of direct-acting oral anticoagulants (DOACs) has increased secondary to the mounting evidence for comparable efficacy and potentially superior safety to vitamin K antagonists (VKAs) in the general population. However, insufficient data regarding DOAC use in solid organ transplant (SOT) recipients and numerous pharmacokinetic and pharmacodynamic considerations limit their use in this highly selected patient population. A systematic review of recent clinical evidence on the safety and efficacy of DOACs compared to VKAs in SOT recipients was conducted. Additional considerations including transplant-specific strategies for DOAC reversal and common pharmacokinetic/pharmacodynamic concerns were also reviewed. Although current evidence is limited to single-center retrospective analyses, DOACs, especially apixaban, appear to be a safe and effective alternative to VKAs for SOT recipients with stable graft function and without drug-drug interactions. Reliable data on DOAC reversal at the time of transplant surgery are lacking, and clinicians should consider idarucizumab, andexanet alfa, and other non-specific reversal agents on an individual patient basis. There is no evidence supporting deviations from the Food and Drug Administration labeling recommendations for DOAC dosing in the setting of drug-drug interactions, obesity, and renal function, especially in patients on hemodialysis.

Safety and efficacy of catheter ablation for atrial fibrillation in abdominal solid organ (renal and hepatic) transplant recipients: A single-center pilot experience

BACKGROUND

Atrial fibrillation (AF) is common in abdominal solid organ transplant recipients and a cause of morbidity and mortality in this population. However, the outcomes of catheter ablation (CA) in transplant recipients with AF remain unclear. This study aimed to elucidate the outcomes of CA in renal and hepatic transplant recipients.

METHODS AND RESULTS

Between 2015 and 2019, 14 transplant recipients (nine with kidney transplantation and five with liver transplantation) were enrolled from among 10,741 AF patients and underwent CA at Anzhen Hospital. Another 56 patients matched by age, sex, and AF type were selected as the control group (four controls for each transplant recipient). During a mean follow-up of 30.0 ± 13.3 months after the initial procedure, 10 (71.4%) of the transplant patients, compared to 41 (73.2%) of the control patients, remained free from AF recurrence (p = 1.000). A repeated procedure was performed in one transplant patient and in six control subjects. Consequently, 11 (78.6%) of the transplant patients, compared to 46 (82.1%) of controls, were in sinus rhythm after the repeated ablation (p = .715). Notably, Kaplan-Meier analysis did not demonstrate any significant differences in the atrial arrhythmia-free rate after the initial and repeated procedure between the two groups. Vascular complications were identified in one transplant patient and two control subjects, while no life-threatening complications were observed in either group. There was no transient allograft dysfunction in transplant recipients after CA.

CONCLUSION

CA is safe and effective in abdominal solid transplant recipients, and maybe an optimal therapeutic strategy for this group.

Prothrombin Complex Concentrate in Liver Transplant Surgery: Correction of Therapeutic Anticoagulation and the Coagulopathy of End-Stage Liver Disease: Case Series

Suggested treatment for active bleeding or invasive procedure prophylaxis has been described in the setting of end-stage liver disease (ESLD) in patients not receiving anticoagulation, and has included fresh frozen plasma (FFP), prothrombin complex concentrates (PCC), platelets, and cryoprecipitate. Today, the therapy for pharmacologically anticoagulated patients with ESLD presenting for liver transplant surgery remains controversial, poorly studied, and physician-dependent. We observed a variety of treatments administered at initiation of liver transplantation to correct acquired coagulopathy at our leading transplant center and present these cases. Three patients receiving preoperative therapeutic anticoagulation with warfarin for acute deep venous thrombosis and/or atrial fibrillation were transfused PCC, FFP, and/or cryoprecipitate for liver or liver-kidney transplant surgery. No thrombotic complications occurred, and one patient required reoperation for hemorrhage. We report data from these cases including estimated blood loss, presence of complications, duration of ICU stay, and length of hospitalization. Perioperative orthotopic liver transplant hematologic management and a review of relevant literature is presented.

Absence of interaction between rivaroxaban, tacrolimus and everolimus in renal transplant recipients with deep vein thrombosis or atrial fibrillation

No data are available on rivaroxaban use in renal transplant recipients and on its surmised interaction with immunosuppressants. The aim was to investigate potential interactions between rivaroxaban and immunosuppressants in this setting. Renal transplant recipients with a stable renal function treated with rivaroxaban and tacrolimus with or without everolimus were investigated. All drugs and creatinine concentrations were determined daily for 2 weeks after the start of anticoagulation. Blood samples were drawn at 8.00 am and 3-4 h later for trough and peak concentrations, respectively. Bleeding and thrombotic events were recorded during a minimum follow-up of 6 months. In 8 renal transplant patients, rivaroxaban levels showed a predictable pharmacokinetic trend, both at C_trough (30-61 μg/L) and at C_peak (143-449 μg/L), with limited variability in the 25th-75th percentile range. Tacrolimus (C_trough 3-13 μg/L; C_peak 3-16 μg/L), everolimus (C_trough 3-11 μg/L; C_peak 5-17 μg/L) and creatinine concentrations were stable as well. Immunosuppressors variability before and after rivaroxaban were 30% and 30% for tacrolimus, 27% and 29% for everolimus, respectively, as well as 14% and 3% for creatinine. For rivaroxaban monitoring, the reference change value better performed in identifying significant variations of its concentration. No patient had bleeding or thrombotic events, worsening of renal graft function, and signs of immunosuppressants toxicity during a mean follow-up of 23 (9-28) months. In conclusion, rivaroxaban does not seem to interact with tacrolimus and everolimus in renal transplant recipients. Both anticoagulant and immunosuppressive effects seem warranted, without major bleeding complications and effect on the graft function.

Assessment of direct oral anticoagulants administered as potentially inappropriate medications to elderly inpatients

Background There is evidence that direct oral anticoagulants administered as potentially inappropriate medications increase the risk of bleeding and thromboembolic complications, which represent serious threats to human health. Objective To identify direct oral anticoagulants administered as potentially inappropriate medications for hospitalized patients aged ≥ 65 years in our hospital, and to determine associated factors and the correlation between potentially inappropriate medications and adverse reactions. Setting Xi'an Central Hospital, China. Method A retrospective cross-sectional study of elderly hospitalized patients who received either dabigatran or rivaroxaban at Xi'an Central Hospital between June 1, 2018 and June 1, 2019. The evaluation criteria of direct oral anticoagulants were formulated based on drug labels, disease guidelines and the 2019 American Geriatrics Society Beers Criteria, and any non-compliance with the criteria was considered to be potentially inappropriate medications. The Pearson chi-square test and a binary logistic regression model were used. Main outcome measure Factors associated with potentially inappropriate medications and correlation between potentially inappropriate medications and adverse reactions. Results This study analysed 315 patients aged ≥ 65 years. The application of our evaluation criteria identified 155 (49.2%) instances of potentially inappropriate medications, comprising 5 different types of potentially inappropriate medications. Fifteen adverse drug reactions occurred in the study participants. The Pearson chi-square test revealed significant differences in number of medications (p = 0.021) and creatinine clearance rate (p = 0.002) between potentially inappropriate medications and non-potentially inappropriate medications groups. In the binary logistic regression model, potentially inappropriate medications use was associated with creatinine clearance (creatinine clearance < 30: OR = 3.590, 95% CI = 1.214-10.615, p = 0.021), and there was no significant correlation between potentially inappropriate medications and adverse drug reactions after eliminating the confounding factors (age, length of hospitalization, number of disease combined) with p values of less than 0.25 (adjusted OR = 0.372, 95% CI = 0.117-1.182, p = 0.094). Conclusion This study revealed that the incidence of potentially inappropriate medications was relatively high, number of medications and creatinine clearance differed significantly between potentially inappropriate medications and non-potentially inappropriate medications groups, and potentially inappropriate medications was associated with creatinine clearance (creatinine clearance < 30 mL/min), but there was no significant correlation between potentially inappropriate medications and adverse drug reactions after eliminating the confounding factors.

Incidence of Direct Oral Anticoagulant Prescriptions in Kidney Transplant Recipients in Ontario, Canada

BACKGROUND

Kidney transplant recipients (KTRs) are routinely excluded from direct oral anticoagulant (DOAC) trials. Given the lack of safety and efficacy data in this population, we examined real-world prescribing practices of DOACs in KTRs.

METHODS

We conducted a retrospective cohort study using linked administrative data sets in Ontario, Canada. All adult KTRs (n = 5580) from June 23, 2009, to March 31, 2017, were included. The primary outcomes were the first prescription for a DOAC or warfarin. Patients were censored on graft failure, death, or end of follow-up.

RESULTS

The mean age was 55 (SD, 14) years; 63% were male, and 65% had received a deceased donor kidney. Over a median follow-up of 5.5 and 4.7 years, 224 KTRs (4.0%) and 824 KTRs (14.8%) were prescribed DOACs and warfarin, respectively. The rates of DOAC and warfarin prescriptions were 8.1 and 32.6 per 1000 person-years, respectively. Older age, receipt of a kidney transplant in more recent years, and higher baseline estimated glomerular filtration rate were associated with DOAC prescription compared with warfarin. Patients with multiple comorbidities and a history of deep venous thromboembolism had a lower risk of DOAC prescription compared with warfarin. When examined by era, the incidence rate of both DOAC and warfarin prescriptions increased significantly over time.

CONCLUSIONS

Despite limited safety and efficacy data, DOACs are prescribed to KTRs. However, warfarin still remains more commonly prescribed in this selected patient population. Anticoagulant prescriptions overall are on the rise in KTRs. Further study is needed to determine the safety and efficacy of DOACs in KTRs.

Utilization of direct-acting oral anticoagulation in solid organ transplant patients: A national survey of institutional practices

The safety and efficacy of direct-acting oral anticoagulants (DOACs) and reversal strategies are not well established in the solid organ transplant population. This was a survey of pharmacists to assess DOAC and urgent reversal practices among adult transplant programs in the United States. A 27-question survey was distributed to members of transplant pharmacy organization listservs between 5/28/19 and 6/30/19. A total of 115 responses were received from kidney (43.5%), heart (20.0%), lung (18.3%), liver (13.9%), and pancreas (4.4%) transplant programs. DOAC use prior to transplant was mostly prohibited in thoracic programs (77.3%) but more permissive in kidney transplant programs (64.0%). If permitted, apixaban (57.8%) was most preferred. At transplant surgery, reversal of DOAC was performed "as needed" (20.9%) or was not routine (18.3%). DOAC use post-transplant was more permissive (94.3%). A majority of responders follow FDA recommended dosing in the setting of drug-drug interactions (51.1%). Major factors influencing DOAC prescribing decisions included renal function, drug-drug interactions, and insurance. High clinical practice variability exists regarding DOAC utilization and urgent reversal strategies in pre-, peri-, and post-transplant stages. While more research is needed to refine the clinical landscape, many institutions are using DOAC therapy under the perception that they pose a similar risk of bleeding compared to a non-transplant population.

Cardiovascular disease in the kidney transplant recipient: epidemiology, diagnosis and management strategies

Kidney transplantation (KT) is the optimal therapy for end-stage kidney disease (ESKD), resulting in significant improvement in survival as well as quality of life when compared with maintenance dialysis. The burden of cardiovascular disease (CVD) in ESKD is reduced after KT; however, it still remains the leading cause of premature patient and allograft loss, as well as a source of significant morbidity and healthcare costs. All major phenotypes of CVD including coronary artery disease, heart failure, valvular heart disease, arrhythmias and pulmonary hypertension are represented in the KT recipient population. Pre-existing risk factors for CVD in the KT recipient are amplified by superimposed cardio-metabolic derangements after transplantation such as the metabolic effects of immunosuppressive regimens, obesity, posttransplant diabetes, hypertension, dyslipidemia and allograft dysfunction. This review summarizes the major risk factors for CVD in KT recipients and describes the individual phenotypes of overt CVD in this population. It highlights gaps in the existing literature to emphasize the need for future studies in those areas and optimize cardiovascular outcomes after KT. Finally, it outlines the need for a joint 'cardio-nephrology' clinical care model to ensure continuity, multidisciplinary collaboration and implementation of best clinical practices toward reducing CVD after KT.

Anticoagulation management strategies in heart transplantation

Anticoagulation before, during, and after heart transplantation (HT) presents unique challenges to clinicians. Bleeding and thrombotic morbidity continues to affect this patient population throughout all phases of the HT journey. Reversal is commonly required since patients are commonly bridged to HT with left ventricular assist devices, which require chronic anti platelet and anticoagulation. Caution must be exercised in patients requiring cardiopulmonary bypass during surgery who are at risk of complications from heparin induced thrombocytopenia. The reported incidence of venous thromboembolism following HT is high, particularly during the first post-HT year, most likely due to surgery, biopsies, specific immunosuppression (mTOR inhibitors) and immobilization. It is crucial to maintain long-term oral anticoagulation after the first venous thromboembolism event, especially when risk factors exist. A major issue, and one for which there remains considerable debate, is the optimal treatment of such complications, particularly upper extremity venous thrombosis. For both warfarin and the thrombin inhibitors or Factor Xa inhibitors, the clinician must determine potential drug interactions based on the HT drug regimen, and then develop a patient-specific management strategy.

Safety of direct-acting oral anticoagulants relative to warfarin in a matched cohort of liver transplant recipients

Despite increasingly widespread utilization of direct-acting oral anticoagulants (DOACs), there remains limited experience with the use of these agents following liver transplantation. We performed a single-center, retrospective review of liver transplant recipients prescribed DOACs or warfarin between January 2014 and January 2018. Patients receiving DOACs were matched with warfarin-treated controls based on discrete clinical parameters and followed from the time of anticoagulant prescription, until treatment discontinuation or study conclusion. The primary endpoint for this review was the incidence of clinically relevant major or non-major bleeding among the treatment groups. Twenty-seven patients prescribed DOACs were identified for inclusion in the review, of which 20 could be matched with suitable warfarin controls. At the conclusion of the study, warfarin-treated patients had a significantly higher incidence of clinically relevant bleeding (45% vs 15%; P = .01). No statistically significant differences were found in the rate of new or recurrent thrombotic events. Multivariable logistic regression demonstrated that warfarin treatment was associated with a significantly higher odds of a bleeding event compared to treatment with a DOAC (OR = 6.9; 95% CI, 1.1-44.6). DOAC use appears relatively safe compared with warfarin in select liver transplant recipients. Patient-specific factors still bear consideration when selecting between the various anticoagulant options.

Efficacy and safety of non-vitamin K antagonist oral anticoagulants post-kidney transplantation

BACKGROUND

Novel oral anticoagulants (NOACs) were developed as alternatives to vitamin K antagonists, primarily warfarin, as they do not require routine monitoring and have limited drug-drug and drug-food interactions. However, the efficacy and safety of these agents in kidney transplantation are not well studied.

AIM

To assess the profile and safety of NOACs for patients who had kidney transplantation, and to provide recommendations and guidelines on therapeutic strategies in these patients.

METHODS

This was a retrospective study carried out among adult patients who were actively on the following NOACs (apixaban, rivaroxaban or dabigatran) in our renal transplantation program from December 2015 to December 2016. The patients were identified primarily through electronic medical record system (patient data linkage). Data on the clinical and laboratory profile of the patients were retrieved and analyzed with SPSS 22.0.

RESULTS

Complete data on 42 renal transplant patients were retrieved: 59.5% males, 90.5% were whites and 66.7% were older than 60 years old. The mean duration since renal transplantation of the patients was 8.8 ± 7.4 years. The most common risk factors for the development of end-stage renal disease in the subjects were hypertension (19.0%), polycystic kidney disease (19.0%), followed by diabetic nephropathy (16.7%) and chronic glomerulonephritis (16.7%). The main indications for NOACs use in the cohort were atrial fibrillation in 25 patients (59.5%) and venous thromboembolism in 10 patients (23.8%). Overall, 29 patients (69%) were treated with apixaban, 10 patients (23.8%) with rivaroxaban and 3 patients (7.14%) with dabigatran. No (0%) thromboembolic events were observed during the one-year period, but 3 (7.1%) bleeding events occurred in the cohort consisting of 1 patient treated with rivaroxaban 15 mg daily and 2 patients who received apixaban 2.5 mg twice daily. There were no significant changes in serum tacrolimus level three days after the initiation of NOACs among patients treated with tacrolimus (pre- and post-NOACs tacrolimus levels were 7.2516 and 7.8867 ng/mL, P = 0.55, respectively). Also, after one-year of treatment with NOACs there were no significant changes in the pre- and post-NOACs serum creatinine level (P = 0.772) and estimated glomerular filtration rates (P = 0.232).

CONCLUSION

No thromboembolic events or significant changes in renal profile were observed in our cohort of kidney transplant recipients who were treated with NOACs for at least a year. However, a few bleeding events were observed. This calls for further well-planned randomized controlled trials to assess the efficacy and safety of NOACs among renal transplant recipients.

Safety and efficacy of direct oral anticoagulants for venous thromboembolism and stroke prophylaxis in patients with hematologic malignancies

Purpose

Low-molecular-weight heparins are currently the recommended antithrombotic therapy for treatment and prevention of malignancy-related venous thromboembolism. Currently, the evidence evaluating direct oral anticoagulants versus low-molecular-weight heparins or a vitamin K antagonist in cancer patients with hematologic malignancies is limited. We evaluated the safety and efficacy of direct oral anticoagulants for venous thromboembolism treatment or stroke prevention for non-valvular atrial fibrillation in patients with hematologic malignancies.

Methods

This was a retrospective evaluation of adult patients with hematologic malignancies who received at least one dose of the Food and Drug Administration-approved direct oral anticoagulant for venous thromboembolism treatment or stroke prevention. We determined the frequency of major bleeding events, non-major bleeding events, stroke, systemic embolism, appropriateness of initial direct oral anticoagulant doses, holding practices prior to procedures, and the rate of all-cause mortality. An analysis was also performed to compare the incidence of bleeding between patients with a history of hematopoietic stem cell transplant to non-transplant patients.

Results

A total of 103 patients were identified, with the majority of patients receiving rivaroxaban for venous thromboembolism treatment. Major bleeding events occurred in four patients and no fatal bleeding events occurred. Non-major bleeding occurred in 29 patients, most commonly epistaxis and bruising. Two patients experienced a systemic embolism while on direct oral anticoagulant therapy.

Conclusion

Direct oral anticoagulants may be a safe and effective alternative for anticoagulation therapy in patients with hematologic malignancies. However, larger prospective studies comparing direct oral anticoagulants to low-molecular-weight heparins or vitamin K antagonists are warranted to compare efficacy and safety outcomes in this patient population.

Insights From Practice With Use of Direct Oral Anticoagulants in Transplantation

Solid organ transplant patients are at risk of developing atrial fibrillation and venous thromboembolism. Direct oral anticoagulants are considered an attractive option for anticoagulation in patients due to their convenience; however, strong evidence of their use in transplantation is lacking. We conducted a search using Pubmed, Embase, and Scopus databases, in addition to International Society of Heart and Lung transplantation and American Transplant Congress abstracts (from 2012 through December 2017). Fourteen articles were reviewed that included case reports, retrospective case series, or chart review analyses of small cohorts. Based on this review, the findings can only generate hypotheses that should be further studied in a larger randomized cohort. This review can help clinicians gain insight into the use of direct oral anticoagulant in this special population. For now, clinicians should be cautious about their use in this special population.