According to the recommendations provided by the American College of Chest Physicians (ACCP 2012), the thrombotic risk of patients previously under treatment with oral anticoagulants, needing treatment interruption because of an invasive procedure, is classified in three groups (7). Patients presenting with AF and a CHADS2 score 0 to 2 (without a history of stroke or transient ischemic event) and patients with a history of venous thromboembolism at least 12 months before but no other risk factors, are considered as low-risk. However, evidence about the perioperative management of oral VKA is limited and stems from observational studies and recommendations provided by scientific societies (11). In fact, there seems to be a great discrepancy between hematologists and primary care physicians regarding the timing and appropriateness of bridging anticoagulation prior to invasive procedures.
Aiming to clarify this controversy, Douketis et al conducted the BRIDGE study, a double-blind, placebo-controlled randomized trial in which, following interruption of warfarin therapy prior to an invasive procedure, patients were randomized to receive either bridging anticoagulation with LMWH or placebo. The objective was to identify the need for bridging anticoagulation in AF patients undergoing invasive procedures. The primary endpoints of the study included the occurrence of arterial thromboembolism and major bleeding episodes within 30 days after the procedure.
The study included 1,884 patients, 950 received placebo and 934 received bridging anticoagulation. The incidence of thromboembolism was 0.4% and 0.3% in the placebo and treatment groups, respectively risk difference, 0.1 percentage points; 95% confidence interval [CI], -0.6 to 0.8; P=0.01 for noninferiority). However, the occurrence of a major hemorrhagic episode was 1.3% and 3.2% in the placebo and treatment groups, respectively (relative risk, 0.41; 95% CI, 0.20 to 0.78; P=0.005 for superiority). The authors concluded that patients not receiving bridging therapy had not only similar thromboembolic complications but fewer major bleeding episodes (12).
In our study, in which bridging anticoagulation was used in all patients, we observed an incidence rate of 0.62% and 2.4% of major and minor bleeding events, respectively.
Misuse of bridging anticoagulation by hematologists and primary care physicians is a matter of concern among scientific societies that have questioned its applicability. Moreover, the Canadian Hematology Society has suggested that bridging anticoagulation should not be offered to patients unless the risk of thrombosis clearly outweighs the risk of hemorrhage, given that the majority of patients will likely not benefit and might result in unwanted complications, increasing cost and avoidable work overload (14).
The study by Rios et al has shown that, in AF patients under VKA treatment, bridging anticoagulation prior to an invasive procedure was independently associated to a higher risk of all peri-procedure complications (15).
In Spain, the use of warfarin is marginal (5.2%) and we lack specific data regarding bridging anticoagulation. However, the management of non-valvular AF patients under acenocoumarol does not seem to be different from that of warfarin and data is generally extrapolated (16).
An increasing number of patients under VKA necessarily means more personnel working in Anticoagulation Units. In our area, management and control of oral anticoagulation therapy has been decentralized and shared with general practitioners using a telemedicine system.
This system enhances communication between hematologists and primary care physicians, reduces costs attributed to specialized consultations, and improves patient satisfaction (17,18). This decentralization process granted new competences to primary care physicians, who have demonstrated good quality management of this therapy (19,20). In our center, the electronic clinical record application allows to issue recommendation forms about withdrawal of anticoagulation, so the patient can undergo bridging anticoagulation as outpatient treatment, thus avoiding hospital stay, as also reported by Pappas et al (21). However, costs do increase whenever anticoagulation withdrawal and bridging therapy are unnecessarily offered to patients. Given that the cost of controlling oral anticoagulation therapy is lower in primary care than in specialized consultation (22), it seems reasonable that forms about anticoagulation withdrawal prior to invasive procedures should ideally be issued by primary care physicians, thus reducing specialist workload. We believe that primary care physicians should be involved in the implementation of oral anticoagulation guidelines. A close observation of such guidelines should result not only in fewer adverse effects and complications but also in reduced costs (23).
In our center, we have been using unnecessary bridging therapy with LMWH which resulted in cases of post-procedure hemorrhage. It increased costs because of Emergency attendance and hospital stay due to the management of hemorrhagic complications. In Europe, such discrepancy between Guidelines’ recommendations and clinical practice has led to the design of electronic resources aimed to help in the correct application of protocols and to enhance adherence to guidelines (24).