Yao, Xiaoxi

Background Incidental mobile thrombi are commonly found on endovascular leads of cardiac implantable electronic devices ( CIED s). Transseptal puncture for catheter ablation of arrhythmia poses a risk for paradoxical embolism. We examined risk of ischemic stroke, transient ischemic attack ( TIA ), or systemic embolism after transseptal ablation in patients with and without CIED s. Methods and Results Using a national administrative claims database, 31 720 patients who underwent a transseptal catheter ablation between January 2004 and September 2014 were identified. Two propensity‐matched cohorts were created by matching demographic variables, administrative variables, Charlson Comorbidity Index, CHA 2 DS 2 ‐Vasc score, and year and indication for ablation (5533 and 11 300 patients with and without CIED s). Incidence rates and Cox proportional hazards models were used to estimate risk of ischemic stroke, TIA , or systemic embolism for patients with and without CIED s. Impact of oral anticoagulation ( OAC ) use on the endpoint was examined. Over a mean follow‐up of 2.1 years, the incidence of the combined endpoint was 1.9 per 100 person‐years in patients with CIED s and 1.5 per 100 person‐years in patients without CIED s ( P =0.03). Among patients not on OAC , presence of a cardiac device was associated with an increased risk (hazard ratio [ HR ], 1.71 [1.24–2.35]; P <0.01), whereas there was no association noted among patients treated with OAC ( HR , 0.98 [0.75–1.28]). Conclusion CIED s are associated with an increased risk of stroke, TIA , or systemic embolism after transseptal ablation, but this risk is attenuated with postablation OAC use. Role of anticoagulation post‐transseptal ablation in patients with CIED warrants further investigation.

Background In comparison to warfarin, non–vitamin K antagonist oral anticoagulants ( NOAC s) have the advantages of ease of dosing, fewer drug interactions, and lack of need for ongoing monitoring. We sought to evaluate whether these advantages translate to improved adherence and whether adherence is associated with improved outcomes in patients with atrial fibrillation. Methods and Results We performed a retrospective cohort analysis by using a large US commercial insurance database to identify 64 661 patients with atrial fibrillation who initiated warfarin, dabigatran, rivaroxaban, or apixaban treatment between November 1, 2010, and December 31, 2014. During a median of 1.1 y of follow‐up, 47.5% of NOAC patients had a proportion of days covered of ≥80%, compared with 40.2% in warfarin patients ( P <0.001). Patients with CHA 2 DS 2 ‐ VAS c (risk based on the presence of congestive heart failure, hypertension age 65–74 y, age ≥75 y, diabetes mellitus, prior stroke or transient ischemic attack, vascular disease, sex category) score ≥4 were at increased risk of stroke when they were not taking anticoagulation ≥1 month versus <1 week (1–3 months: hazard ratio [ HR ] 1.96, 3–6 months: HR 2.64, ≥6 months: HR 3.66; all P <0.001). Patients with CHA 2 DS 2 ‐ VAS c score 2 or 3 were at increased risk of stroke when they were not taking anticoagulation ≥6 months ( HR 2.73, P <0.001). In these patients with CHA 2 DS 2 ‐ VAS c score ≥2, nonadherence was not associated with intracranial hemorrhage. Among patients with CHA 2 DS 2 ‐ VAS c score 0 or 1, time not taking anticoagulation was not associated with stroke, but not taking anticoagulation ≥3 months was associated with a significant reduction of bleeding. Conclusions Adherence to anticoagulation is poor in practice and may be modestly improved with NOAC s. Adherence to therapy appears to be most important in patients with CHA 2 DS 2 ‐ VAS c score ≥2, whereas the benefits of anticoagulation may not outweigh the harms in patients with CHA 2 DS 2 ‐ VAS c score 0 or 1.

Background There is significant practice variation in oral anticoagulation ( OAC ) use following catheter ablation for atrial fibrillation. It is not clear whether the risk of cardioembolism increases after discontinuation of OAC following catheter ablation. Methods and Results We identified 6886 patients within a large national administrative claims database who underwent catheter ablation for atrial fibrillation between January 1, 2005, and September 30, 2014. We assessed the effect of time off of OAC by CHA 2 DS 2 ‐ VAS c score (after adjusting for other comorbidities) on risk of cardioembolism, using Cox proportional hazards models. There was an increase in the use of non–vitamin K OAC after ablation from 0% in 2005 to 69.8% in 2014. OAC discontinuation was high, with only 60.5% and 31.3% of patients remaining on OAC at 3 and 12 months, respectively. The rate of discontinuation was higher in low‐risk patients (82% versus 62.5% at 12 months for CHA 2 DS 2 ‐ VAS c 0–1 versus ≥2, respectively; P <0.001). Stroke occurred in 1.4% of patients with CHA 2 DS 2 ‐ VAS c ≥2 and 0.3% of those with CHA 2 DS 2 ‐ VAS c 0 or 1 over the study follow‐up. The risk of cardioembolism in the first 3 months after ablation was increased among those with any time off OAC (hazard ratio 8.06 [95% CI 1.53–42.3], P <0.05). The risk of cardioembolism beyond 3 months was increased with OAC discontinuation among high‐risk patients (hazard ratio 2.48 [95% CI 1.11–5.52], P <0.05) but not low‐risk patients. Conclusion The overall risk of stroke in postablation patients is low; however, OAC discontinuation after ablation is common and is associated with increased risk of cardioembolism for all patients within the first 3 months and for high‐risk patients in the long term. Continuing OAC for at least 3 months in all patients and indefinitely in high‐risk patients appears to be the safest strategy.