Bridging therapy and oral anticoagulation: current and future prospects:

Is Continuing Anticoagulation or Antiplatelet Therapy Safe Prior to Kidney Transplantation?

Background

Patients undergoing kidney transplantation are often placed on anticoagulation or antiplatelet therapy, and their perioperative management is often challenging. This study aimed to determine the safety of continuing anticoagulation or antiplatelet therapy prior to kidney transplantation. The primary outcome was bleeding after transplantation.

Material/Methods

Patients who underwent kidney transplantation between January 2017 and July 2019 were included and divided into 3 groups: pretransplant anticoagulation with warfarin (WARF; n=23); pretransplant antiplatelet therapy with clopidogrel/aspirin (ASA/CLOP; n=32); and control (CTL; n=197). Patients received kidneys from live or deceased donors. Preoperative INRs and platelet counts were compared to ensure therapeutic anticoagulation in the warfarin group and no significant platelet count variation among groups. The primary outcome was graft exploration for bleeding at 3 and 6 months after transplantation. Secondary outcomes included perioperative transfusion requirements, prolonged length of stay (>7 days), and outcomes at 3 and 6 months after transplantation, including hemodialysis and rejection rates and creatinine levels.

Results

Pretransplant INR was significantly greater in the warfarin group (CTL 1.1, WARF 2.2, ASA/CLOP 1.2; P<0.01). There were no differences in pretransplant platelet count (CTL 202×10³, WARF 186×10³, ASA/CLOP 194×10³; P=0.31), graft exploration for bleeding at 3 (CTL 3%, WARF 0%, ASA/CLOP 3%; P=0.69) and 6 months after transplantation (CTL 1%, WARF 4%, ASA/CLOP 0%; P=0.12), or perioperative blood transfusion requirements (CTL 4%, WARF 4%, ASA/CLOP 14%; P=0.13). Prolonged length of stay was similar (CTL 24%, WARF 26%, ASA/CLOP 44%; P=0.08). There were no significant differences among groups at 3 months in dialysis (CTL 2%, WARF 0%, ASA/CLOP 0%; P=0.71), creatinine (CTL 1.5 mg/dL, WARF 1.7 mg/dL, ASA/CLOP 1.7; P=0.13), or rejection (CTL 6%, WARF 0%, ASA/CLOP 0%) or at 6 months in dialysis (CTL 3%, WARF 0%, ASA/CLOP 0%; P=0.49), creatinine (CTL 1.5 mg/dL, WARF 1.7 mg/dL, ASA/CLOP 1.5; P=0.49), or rejection (CTL 1%, WARF 0%, ASA/CLOP 3%).

Conclusions

Continuing anticoagulation or antiplatelet was safe in not increasing bleeding complications or perioperative transfusion requirements. Outcomes were similar at 3 and 6 months among groups. This strategy avoids exposing patients to risk of thrombosis if treatment is held and simplifies proceeding to transplantation.

Periprocedural management of patients receiving a vitamin K antagonist or a direct oral anticoagulant requiring an elective procedure or surgery

The periprocedural management of patients receiving chronic therapy with oral anticoagulants (OACs), including vitamin K antagonists (VKAs) such as warfarin and direct OACs (DOACs), is a common clinical problem. The optimal perioperative management of patients receiving chronic OAC therapy is anchored on four key principles: (i) risk stratification of patient-related and procedure-related risks of thrombosis and bleeding; (ii) the clinical consequences of a thrombotic or bleeding event; (iii) discontinuation and reinitiation of OAC therapy on the basis of the pharmacokinetic properties of each agent; and (iv) whether aggressive management such as the use of periprocedural heparin bridging has advantages for the prevention of postoperative thromboembolism at the cost of a possible increase in bleeding risk. Recent data from randomized trials in patients receiving VKAs undergoing pacemaker/defibrillator implantation or using heparin bridging therapy for elective procedures or surgeries can now inform best practice. There are also emerging data on periprocedural outcomes in the DOAC trials for patients with non-valvular atrial fibrillation. This review summarizes the evidence for the periprocedural management of patients receiving chronic OAC therapy, focusing on recent randomized trials and large outcome studies, to address three key clinical scenarios: (i) can OAC therapy be safely continued for minor procedures or surgeries; (ii) if therapy with VKAs (especially warfarin) needs to be temporarily interrupted for an elective procedure/surgery, is heparin bridging necessary; and (iii) what is the optimal periprocedural management of the DOACs? In answering these questions, we aim to provide updated clinical guidance for the periprocedural management of patients receiving VKA or DOAC therapy, including the use of heparin bridging.

Comparison of uninterrupted warfarin and bridging therapy using low-molecular weight heparin with respect to the severity of bleeding after dental extractions in patients with prosthetic valves

Objective:

The management of anticoagulated patients with warfarin during dental extraction is an intricate issue. We carefully designed the current study so that the amount of bleeding was measured with objective methods and the data from the same patient in different dental extraction appointments could be compared, eliminating the bleeding diathesis differences of patients.

Methods:

This prospective and controlled study was conducted in 36 adult patients with prosthetic valve requiring multiple tooth extractions. The first dental extraction was performed without the discontinuation of warfarin therapy, and the second procedure was performed with a discontinuation of warfarin and bridging with low-molecular weight heparin (LMWH). The two dental extraction protocols in the same patient group were compared. The total amount of bleeding was calculated as the difference between the weights of gauze swabs used before and after the tamponade; the number of gauze swabs used for bleeding control in the first 48 h was recorded.

Result:

The median number of used gauze swabs was 2.5 (IQR: 1–5) and 3.0 (IQR: 2–7) in the first and second dental extraction procedures, respectively. The median bleeding time was 50.0 (IQR: 20–100) in the first procedure compared with 60.0 (IQR: 40–140) min in the second procedure. The mean amounts of bleeding were 2194±1418 mg in the first dental extraction procedure and 2950±1694 mg in the second dental extraction procedure. The median number of used gauze swabs, the median bleeding time, and the mean amount of bleeding were statistically higher in the second dental extraction procedure (p<0.001).

Conclusion:

Continued warfarin treatment at the time of dental extractions reduces the total amount of bleeding compared with bridging therapy in patients with prosthetic valves.

Risk factors for artificial urinary sphincter failure

PURPOSE

To analyze revision rates and risk factors for artificial urinary sphincter failure.

METHODS

Eighty-four patients underwent implantation of an artificial urinary sphincter in one reference center. Continence rates were defined by daily pad usage. Influence of predefined risk factors for device explantation, revision, differences in preoperative pad usage, and device survival was analyzed using Chi-squared test, Wilcoxon signed-rank test, and Kaplan-Meier analysis. A multivariate analysis was performed using a logistic regression model. A p value below 0.05 was considered statistically significant.

RESULTS

After a mean follow-up of 39.7 months, the device was still in situ in 64 patients. In univariate analysis, perioperative need of anticoagulation led to a significant increase in urethral erosion (6 vs. 30 %; p = 0.002) and explantation rate (15 vs. 34 %; p = 0.047). Pelvic irradiation increased postoperative infection rates significantly (0 vs. 10 %; p = 0.018). Penoscrotal approach led to significant increase in urethral erosion rate (0 vs. 21 %; p = 0.015). Implantation of a double cuff led to a significant increase in explantation rate (58 vs. 24 %; p = 0.014), revision rate (75 vs. 38 %; p = 0.017), and infection rate (17 vs. 1 %; p = 0.008). When using cuff size of 3.5 cm, revision rate (20 vs. 50 %; p = 0.026) as well as incontinence rates (40 vs. 82 %; p = 0.014) was significantly lower. In multivariate analysis, only perioperative anticoagulation and double-cuff placement were independent predictors of artificial urinary sphincter failure.

CONCLUSIONS

Our findings highlight the influence of perioperative anticoagulative therapy. In addition, the current study provides further evidence that double-cuff implantation should be performed only with caution during primary implantation.

Bemiparin versus unfractionated heparin as bridging therapy in the perioperative management of patients on vitamin K antagonists: the BERTA study

BACKGROUND AND OBJECTIVE

The management of patients on vitamin K antagonist therapy who require an invasive procedure is problematic. A randomised, controlled, double-blind clinical trial was designed to compare the efficacy and safety of bemiparin, a low molecular weight heparin (LMWH), with unfractionated heparin (UFH) as bridging therapy: the BERTA (BEmiparin Randomised Trial on bridging Anticoagulants) study.

METHODS

Two hundred and six patients on long-term oral anticoagulation therapy (OAT) requiring an invasive procedure were randomized to receive bridging therapy with bemiparin + matching placebo or UFH. OAT was resumed on day 1. The study medication was continued for 5-6 days after the procedure. The primary efficacy endpoint was the combined incidence of arterial and venous thromboembolic events. The primary safety endpoint was the incidence of major bleeding within 10 days after the invasive procedure.

RESULTS

There were no thromboembolic events in the bemiparin group, but two events (2.2 %) occurred in the UFH group. No major bleeding occurred in either group, but minor bleeding occurred in four patients (4.3 %) and six patients (6.1 %) in the bemiparin and UHF groups, respectively. No deaths and no cases of severe thrombocytopenia occurred during the whole study period.

CONCLUSION

Despite its small size, the BERTA study is the first randomised, double-blind clinical trial comparing UFH with a fixed high-risk thromboprophylactic dose of an LMWH as bridging therapy. There were no thromboembolic events and fewer bleeding episodes in the bemiparin group than in the UFH group, hence we suggest that bemiparin is at least as safe as UFH as bridging therapy.

Rapid bedside coagulometry prior to urgent neurosurgical procedures in anticoagulated patients

INTRODUCTION

With the increased use of oral anticoagulation with vitamin K antagonists, emergency physicians encounter a growing number of patients requiring a rapid reversal of anticoagulant effects in order to perform urgent surgical procedures. Initiation of these procedures can be delayed because the coagulation status has to be assessed through examination of blood samples in central laboratories (CL). This delay may lead to negative effects, especially in potentially life-threatening conditions such as intracranial haemorrhage. Point-of-care (POC) devices for assessment of international normalized ratio (POC INR) have improved the management of anticoagulation therapy in the outpatient setting. The use of these devices may also have beneficial effects in the treatment of anticoagulated patients requiring urgent neurosurgical procedures. The primary aim of this study was to analyse the potential of POC-guided assessment of INR to reduce time to potentially life-saving neurosurgery in this setting. Feasibility and accuracy as well as the gain of time through the use of this device were analysed.

MATERIALS AND METHODS

The POC coagulometer CoaguChek XS(®) was used in 17 patients with a history of anticoagulant use and a condition requiring urgent anticoagulant reversal prior to neurosurgical procedures (burr-hole trepanation: n = 8, craniotomy: n = 7, laminectomy: n = 2).

RESULTS

No technical difficulties occurred and rapid assessment of INR was achieved in all cases within 2 min. POC INR values correlated well with CL INR assessment with a mean INR deviation of 0.036 ± 0.12. The mean gain of time through the use of the POC INR device compared with CL assessment of INR was 47 ± 6 min (range: 37-61 min).

CONCLUSION

Our initial experiences with a POC INR device in anticoagulated patients undergoing urgent neurosurgical procedures demonstrate that its use may contribute to an improved management of these patients.

The current status of bridging anticoagulation

For patients prescribed chronic vitamin K antagonist therapy requiring a surgical or invasive procedure, the question of whether or not to bridge and how to bridge is commonly encountered in clinical practice. Bridging anticoagulation has evolved over the years and the evidence base for current practice is deficient in many areas. Clinical trials currently being completed with conventional anticoagulants should help strengthen the evidence base for future practice. The availability of novel oral anticoagulants is a welcome addition, though their optimal management peri-procedure is yet to be determined. Prospective multi-centre controlled studies that can provide the evidence base for novel oral anticoagulant peri-procedural management are required.

How I treat anticoagulated patients undergoing an elective procedure or surgery

The periprocedural management of patients receiving long-term oral anticoagulant therapy remains a common but difficult clinical problem, with a lack of high-quality evidence to inform best practices. It is a patient's thromboembolic risk that drives the need for an aggressive periprocedural strategy, including the use of heparin bridging therapy, to minimize time off anticoagulant therapy, while the procedural bleed risk determines how and when postprocedural anticoagulant therapy should be resumed. Warfarin should be continued in patients undergoing selected minor procedures, whereas in major procedures that necessitate warfarin interruption, heparin bridging therapy should be considered in patients at high thromboembolic risk and in a minority of patients at moderate risk. Periprocedural data with the novel oral anticoagulants, such as dabigatran, rivaroxaban, and apixaban, are emerging, but their relatively short half-life, rapid onset of action, and predictable pharmacokinetics should simplify periprocedural use. This review aims to provide a practical, clinician-focused approach to periprocedural anticoagulant management.

Periprocedural heparin bridging in patients receiving vitamin K antagonists: systematic review and meta-analysis of bleeding and thromboembolic rates

BACKGROUND

Periprocedural bridging with unfractionated heparin or low-molecular-weight heparin aims to reduce the risk of thromboembolic events in patients receiving long-term vitamin K antagonists. Optimal periprocedural anticoagulation has not been established.

METHODS AND RESULTS

MEDLINE, EMBASE, and Cochrane databases (2001-2010) were searched for English-language studies including patients receiving heparin bridging during interruption of vitamin K antagonists for elective procedures. Data were independently collected by 2 investigators (κ=0.90). The final review included 34 studies with 1 randomized trial. Thromboembolic events occurred in 73 of 7118 bridged patients (pooled incidence, 0.9%; 95% confidence interval [CI], 0.0.0-3.4) and 32 of 5160 nonbridged patients (pooled incidence, 0.6%; 95% CI, 0.0-1.2). There was no difference in the risk of thromboembolic events in 8 studies comparing bridged and nonbridged groups (odds ratio, 0.80; 95% CI, 0.42-1.54). Bridging was associated with an increased risk of overall bleeding in 13 studies (odds ratio, 5.40; 95% CI, 3.00-9.74) and major bleeding in 5 studies (odds ratio, 3.60; 95% CI, 1.52-8.50) comparing bridged and nonbridged patients. There was no difference in thromboembolic events (odds ratio, 0.30; 95% CI, 0.04-2.09) but an increased risk of overall bleeding (odds ratio, 2.28; 95% CI, 1.27-4.08) with full versus prophylactic/intermediate-dose low-molecular-weight heparin bridging. Low-thromboembolic-risk and/or non-vitamin K antagonist patient groups were used for comparison. Study quality was poor with heterogeneity for some analyses.

CONCLUSIONS

Vitamin K antagonist-treated patients receiving periprocedural heparin bridging appear to be at increased risk of overall and major bleeding and at similar risk of thromboembolic events compared to nonbridged patients. Randomized trials are needed to define the role of periprocedural heparin bridging.

Striking a balance between the risks and benefits of anticoagulation bridge therapy in patients with atrial fibrillation: clinical updates and remaining controversies

Long-term anticoagulation with a vitamin K antagonist (VKA) or the new agent dabigatran is recommended to decrease stroke risk in patients with atrial fibrillation. When patients with atrial fibrillation undergo initiation or interruption of VKA therapy, or experience an isolated subtherapeutic international normalized ratio (INR), bridge therapy with a parenteral anticoagulant may be considered. To describe the literature for anticoagulation bridge therapy in patients with atrial fibrillation, we conducted a MEDLINE search (1966-February 2011) of the English-language literature to identify related studies. Ongoing clinical trials were identified through a search of the ClinicalTrials.gov registry. Major national and international guidelines were gathered and evaluated. Additional literature was obtained through review of relevant references of the identified articles. Bridging is not supported by guidelines or clinical trials for patients starting VKA therapy for atrial fibrillation. A subtherapeutic INR value during long-term VKA therapy may be associated with increased thromboembolic events, but the benefit of bridging has not been demonstrated. When VKA therapy is interrupted for procedures, retrospective and cohort data suggest that the decision to bridge should be based on a patient's thromboembolic and bleeding risks associated with the procedure. Typically, it is recommended to use bridge therapy in patients with atrial fibrillation at high risk for thromboembolism, but the benefit of bridging is less clear in patients at low risk. Not all procedures necessitate anticoagulation interruption. Recent trials suggest that VKAs can be continued when patients are undergoing cardiac device procedures and some types of radiofrequency ablation. Several clinical trials are ongoing that will provide more definitive guidance for perioperative anticoagulation management of patients with atrial fibrillation. Patients taking dabigatran are unlikely to require bridge therapy because of a predictable anticoagulant effect and rapid onset of action. However, evidence for optimal perioperative management of dabigatran is needed.