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Introduction:Clinical, health economic and quality of life data supports the Direct Oral Anticoagulants (DOAC) over warfarin in patients at risk for thromboembolic events in the setting of non-valvulvar atrial fibrillation (AF). We sought to evaluate the rate and reasons for ongoing use of warfarin in this population.Methods:Baseline, follow up, medication reconciliation and insurance status data for all patients treated with warfarin at a large AF clinic were collected for this analysis. Contraindication to DOAC use were noted for all patients in the cohort. History of cardiovascular, renal, and hepatic disease, as well as the CHA2DS2-VASc score was obtained for all patients. Canadian Cardiovascular Society 2018 guidelines was used to assess treatment appropriateness.Results:553 patients treated with warfarin at the time of data collection (August 2018, Mean age: 76.0?9.6 years, 52% Male, Mean CHA2DS2-VASc score: 3.5?1.3) were identified and included in this analysis. Of those on warfarin 16% (88) did not have private insurance and were under the age of 65 (no public coverage), 18% (101) had a mechanical valve, 13% (74) had severe renal impairment, 3.4% (19) had a prior major bleeding episode, 10 of which occurred while patient was treated with a DOAC. Remaining 271 (49%) were eligible for treatment with a DOAC.Conclusion:Half of the patients seen at a large atrial fibrillation clinic treated with warfarin as of 2018 had no contraindications to a DOAC, but for reasons related to medication coverage, patient and physician comfort remain on warfarin. This population may derive further benefit from appropriate conversion to a DOAC.

Introduction:Evidence supports utilization of Direct Oral Anticoagulants (DOAC) in patients at risk for stroke or thromboembolic events in the setting of non-valvular atrial fibrillation (AF) . Unfortunately, a number of patients may be at risk of adverse outcomes related to under treatment. We sought to describe DOAC prescribing patterns at a large AF clinic and understand the rate and reasons for subclinical DOAC dosing in these patients.Methods:Baseline, and follow up data for all patients on low dose Rivaroxaban (R) (15mg OD), Dabigatran (D) (110mg BiD), and Apixaban(A) (2.5mg BiD) was collected for analysis. Patients were then stratified into one of 3 groups based on the DOAC prescribed. History of cardiovascular, renal, and hepatic disease, as well as the HAS-BLED score was obtained for all patients.Results:629 patients were included in this analysis (Mean age: 82.3?7.6 years, 68.9% Male, A: 152, D: 242, R: 210). Average HAS-BLED score was 2.4 (A: 2.5?1.1, D: 2.2?0.8, R: 2.7?1.0) for all patients. Overall 63% (A: 52%, D:75%, R: 58%) were appropriately prescribed the lower dose of DOAC. Patients who were undertreated had an average HAS-BLED score of 2.5 (A: 2.5?0.9, D: 2?0.8, R: 2.5?1.0) vs. 2.4 (A: 2.5?1.0, D: 2.3?1.0, R: 2.9?1.0) P=0.16, for patients appropriately receiving the lower dose. Of the undertreated patients 12 had prior history of stroke (A: 3, D: 3, R: 6). Reasons for dose reduction included concomitant treatment with antiplatelet agents in 33 patients (A: 5, D: 7, R: 21), age greater than 80 as a sole factor in 93 patients (A: 56, D: 0, R: 37) and elevated creatinine (Scr>130umol/L) as a sole factor in 21 patients (A: 4, D: 4, R: 13). Of the patients on reduced dose of DOAC, those on Rivaroxaban were the most likely to be undertreated (P=0.03). The most significant factor for prescription of lower DOAC dose was age greater than 80 years (P=0.001).Conclusion:A significant number of patients with non-valvular AF who have clinical indications for oral anticoagulation therapy are undertreated with DOACs. Age greater than 80 appears to be the main reason for undertreatment. This pattern is not driven by objectively higher risk of bleeding according to the patient?s HAS-BLED score.

Introduction:Catheter ablation is the cornerstone treatment for patient with Atrial Fibrillation (AF) refractory to antiarrhythmic medications. CHA2DS2-VASc score has been used to assess stroke risk in patients with AF, as well as a guide for anticoagulation treatment. Risk stratification tools are necessary for appropriate patient management, therefore, in this study we sought to determine whether these risk scores can predict long-term outcomes post AF ablation.Methods:Overall, 1906 patients with AF who underwent catheter ablation between 2004-2018 in a single tertiary care center were studied. ECG, and 48-hour holter monitoring, were used to assess patients at 3, 6, 9 and 12-months post ablation and every 6 months thereafter. Late recurrence was defined as any recurrence of atrial tachyarrhythmia >30 seconds after catheter ablation, and post blanking period. CHA2DS2-VASc score was calculated for each patient and was categorized to those with score of 0, 1, 2, and >2. Patients? outcomes were analyzed over follow-up time for atrial tachyarrhythmia recurrence post blanking period using chi-square and logistic regression.Results:Amongst 1906 patients (mean age: 61.09?10.2 years, male: 1272 (66.7%), Non-Paroxysmal AF (NPAF): 665 (34.9%)), 909 (47.7%) had late recurrence (NPAF: 366, PAF: 543) within mean follow-up time of 1.5?1.8 (0-14.05) years. Patients with higher CHA2DS2-VASc score had significantly greater rate of late recurrence (p=0.003) (Table 1). Univariate logistic regression revealed CHA2DS2-VASc score as a significant predictor of late recurrence (Overall: OR=1.16, P<0.001, CHA2DS2-VASc >2 vs CHA2DS2-VASc =0: OR=1.5, p=0.002). CHA2DS2-VASc score remained a significant predictor of recurrence when adjusted for type of AF (PAF/NPAF) and left atrial diameter, in the multivariate model (Overall: OR=1.14, p=0.003, CHA2DS2-VASc >2 vs CHA2DS2-VASc =0: OR=1.5, p=0.006).Conclusions:CHA2DS2-VASc score can significantly predict late recurrence in patient with atrial fibrillation.