The open label randomised controlled WOEST
The open-label, randomised, controlled WOEST trial (Dewilde et al., 2013) suggested that patients undergoing PCI and are on treatment with warfarin (only two-thirds had AF) should be managed by a combination of warfarin and clopidogrel for 1year post PCI and then with warfarin indefinitely. This was based on the finding that the use of clopidogrel without aspirin was associated with a significant CX5461 cost in bleeding complications and no increase in the rate of thrombotic events. However, the HAS-BLED score and the CHA2DS2-VASc score were not used for decision making in the trial. Also, a placebo was not used instead of aspirin in the double-therapy group. Other limitations of this trial have been discussed (PubMed — NCBI, 2015a).
In patients receiving VKA, the TTR should be maintained above 70% to avoid excess in stroke or haemorrhage. The lower tested dose of the NOACs for stroke prevention is advisable, when used in combination with antiplatelet therapy. The combination of OACs with prasugrel or ticagrelor should be avoided (Lip et al., 2014b).
Oral Anticoagulation and Cardioversion Based on guidelines, in patients with AF of duration more 48h (or AF of unknown duration) oral anticoagulation should be given for at least 3weeks prior to cardioversion, or transoesophageal echocardiography should be performed to rule out left atrial thrombi (Camm et al., 2010). Observational data from the RE-LY trial showed a comparatively low stroke rate related to cardioversion in patients treated with either dabigatran and VKAs (Nagarakanti et al., 2011). Analysis of data from the ARISTOTLE trial showed that patients undergoing cardioversions being managed with either apixaban or warfarin had no thromboembolic events within the first 90days (Flaker et al., 2014). Likewise, there was no difference in the ROCKET-AF trial in the number of strokes or systemic embolisms between warfarin and rivaroxaban following electrical or pharmacological cardioversion (Piccini et al., 2013). The pre-procedural time before cardioversion is usually not delayed with NOACs, as is common with VKAs due to non-therapeutic INRs (unless there is a compliance issue). It is mandatory to explicitly ask the patient about adherence over the previous 3weeks and to document the answer in the history notes. If compliance with NOAC has been confirmed, cardioversion seems acceptably safe. Transoesophageal echocardiogram should be considered if there is doubt about compliance. In patients with stroke risk factors or at high risk of recurrence, OAC should be continued long-term, whether with a VKA or a NOAC (Heidbuchel et al., 2015; Lip & Lane, 2015a).
Catheter Ablation and Anticoagulation in Atrial Fibrillation Catheter ablation should be reserved for patients with AF who remain symptomatic despite optimal medical therapy (Camm et al., 2010). A medium size randomised study showed vasopressin performing catheter ablation of AF without warfarin discontinuation and with a therapeutic INR in patients at high risk for stroke significantly reduces the occurrence of periprocedural stroke/TIA and minor bleeding complications (Di Biase et al., 2014). The VENTURE-AF is the first randomised prospective comparative trial of an uninterrupted NOAC (Rivaroxaban) vs. VKA therapy in patients with AF undergoing catheter ablation. In patients undergoing catheter ablation for AF, the use of uninterrupted oral rivaroxaban was feasible and event rates were similar to those for uninterrupted VKA therapy (Cappato et al., 2015). More trials are underway to define the role of dabigatran [RE-CIRCUIT, DAPPAR-AF (NCT01468155) and ODIn-AF (PubMed — NCBI, 2015b)] around the time of ablation procedures.
Should Bridging Therapy Be Used or Not? Bridging anticoagulation is defined as administration of a short-acting anticoagulant (low molecular weight heparin or unfractionated heparin) during interruption of VKA therapy when the INR is not within a therapeutic range (Douketis et al., 2012). Use of bridging anticoagulation was associated with significantly higher overall rates of bleeding and the data do not support routine use of bridging in anticoagulated patients with non-valvular AF (Steinberg et al., 2015; Douketis et al., 2015).