Real-life anticoagulation treatment of atrial fibrillation after catheter ablation: Possible overtreatment of low-risk patients

Summary

Catheter ablation provides curative treatment for atrial fibrillation (AF). Data on anticoagulation after the procedure are sparse. We investigated real-life antithrombotic treatment after AF ablation and examined its adherence to current recommendations. Eight hundred forty-four patients (age 58 ±10 years) underwent AF ablation. Most patients had a CHADS₂ score of 0 (46%) or 1 (45%). Seven-day Holter was performed at three, six and 12 months after ablation. Decision on anticoagulation treatment was made by general practitioners and referring cardiologists in consultation with the patients. At discharge, anticoagulants were prescribed for the vast majority (94–96%) of patients. This percentage remained high at three and six months (80–90%) without differences between stroke risk groups. At 12 months, the use of anticoagulants was mainly influenced by the detection of recurrence; usage exceeded 90% in all stroke risk groups in patients with recurrences. In patients without recurrences, differences between risk groups were significant but small, ranging from 42% (CHADS₂=0) to 62% (CHADS₂≥2) (p=0.033). In multivariate analysis, the only factor independently associated with oral anticoagulation at 12 months was the detection of recurrences (odds ratio=16.2, p<0.001), whereas the effect of the CHADS₂ score was not significant (p=0.080).The effect of all other examined factors was also not significant. Contrary to current recommendations, anticoagulation after AF ablation is hardly guided by the stroke risk profile and remains high even in low-risk patients. The most important factor influencing the use of anticoagulants is the detection of recurrences during follow-up. This results in possible overtreatment of low-risk patients.

Keywords

Atrial fibrillation - catheter ablation - oral anticoagulation - stroke risk

• References

• 1 Fuster V, Rydén LE, Cannom DS. et al. ACC/AHA/ ESC 2006 guidelines for the management of patients with atrial fibrillation-executive summary: a report of the American College of Cardiology/American Heart Association Task Force on practice guidelines and the European Society of Cardiology Committee for Practice Guidelines. Eur Heart J 2006; 27: 1979-2030.
• 2 Nieuwlaat R, Capucci A, Lip GY. et al. Antithrombotic treatment in real-life atrial fibrillation patients: a report from the Euro Heart Survey on Atrial Fibrillation. Eur Heart J 2006; 27: 3018-3026.
• 3 Nademanee K, Schwab MC, Kosar EM. et al. Clinical outcomes of catheter substrate ablation for highrisk patients with atrial fibrillation. J Am Coll Cardiol 2008; 51: 843-849.
• 4 Oral H, Chugh A, Ozaydin M. et al. Risk of thromboembolic events after percutaneous left atrial radiofrequency ablation of atrial fibrillation. Circulation 2006; 114: 759-765.
• 5 Hindricks G, Piorkowski C, Tanner H. et al. Perception of atrial fibrillation before and after radiofrequency catheter ablation: relevance of asymptomatic arrhythmia recurrence. Circulation 2005; 112: 307-313.
• 6 Calkins H, Brugada J, Packer DL. et al. HRS/ EHRA/ECAS expert consensus statement on catheter and surgical ablation of atrial fibrillation: recommendations for personnel, policy, procedures and followup. Europace 2007; 09: 335-379.
• 7 Gage BF, Waterman AD, Shannon W. et al. Validation of clinical classification schemes for predicting stroke: results from the National Registry of Atrial Fibrillation. JAMA 2001; 285: 2864-2870.
• 8 Kottkamp H, Tanner H, Kobza R. et al. Time courses and quantitative analysis of atrial fibrillation episode number and duration after circular plus linear left atrial lesions: trigger elimination or substrate modification: early or delayed cure?. J Am Coll Cardiol 2004; 44: 869-877.
• 9 Glazer NL, Dublin S, Smith NL. et al. Newly detected atrial fibrillation and compliance with antithrombotic guidelines. Arch Intern Med 2007; 167: 246-252.
• 10 Nieuwlaat R, Olsson SB, Lip GY. et al. Guidelineadherent antithrombotic treatment is associated with improved outcomes compared with undertreatment in high-risk patients with atrial fibrillation. The Euro Heart Survey on Atrial Fibrillation. Am Heart J 2007; 153: 1006-1012.
• 11 Hughes M, Lip GY. Guideline Development Group, National Clinical Guideline for Management of Atrial Fibrillation in Primary and Secondary Care, National Institute for Health and Clinical Excellence. Stroke and thromboembolism in atrial fibrillation: a systematic review of stroke risk factors, risk stratification schema and cost effectiveness data. Thromb Haemost 2008; 99: 295-304.
• 12 Tay KH, Lip GY, Lane DA. Atrial fibrillation and stroke risk prevention in real-life clinical practice. Thromb Haemost 2009; 101: 415-416.
• 13 Fang MC, Go AS, Chang Y. et al. Comparison of risk stratification schemes to predict thromboembolism in people with nonvalvular atrial fibrillation. J Am Coll Cardiol 2008; 51: 810-815.
• 14 Poli D, Antonucci E, Grifoni E. et al. Stroke risk in atrial fibrillation patients on warfarin. Predictive ability of risk stratification schemes for primary and secondary prevention. Thromb Haemost 2009; 101: 367-372.
• 15 McBane RD, Hodge DO, Wysokinski WE. Clinical and echocardiographic measures governing thromboembolism destination in atrial fibrillation. Thromb Haemost 2008; 99: 951-955.
• 16 Poli D, Antonucci E, Grifoni E. et al. Gender differences in stroke risk of atrial fibrillation patients on oral anticoagulant treatment. Thromb Haemost 2009; 101: 938-942.
• 17 Lane DA, Lip GY. Female gender is a risk factor for stroke and thromboembolism in atrial fibrillation patients. Thromb Haemost 2009; 101: 802-805.
• 18 Mant JW. Pro: ‘Warfarin should be the drug of choice for thromboprophylaxis in elderly patients with atrial fibrillation’. Why warfarin should really be the drug of choice for stroke prevention in elderly patients with atrial fibrillation. Thromb Haemost 2008; 100: 14-5.
• 19 Hylek EM. Contra: ‘Warfarin should be the drug of choice for thromboprophylaxis in elderly patients with atrial fibrillation’. Caveats regarding use of oral anticoagulant therapy among elderly patients with atrial fibrillation. Thromb Haemost 2008; 100: 16-17.
• 20 Hart RG, Pearce LA, Aguilar MI. Meta-analysis: antithrombotic therapy to prevent stroke in patients who have nonvalvular atrial fibrillation. Ann Intern Med 2007; 146: 857-867.
• 21 Rietbrock S, Plumb JM, Gallagher AM. et al. How effective are dose-adjusted warfarin and aspirin for the prevention of stroke in patients with chronic atrial fibrillation? An analysis of the UK General Practice Research Database. Thromb Haemost 2009; 101: 527-534.
• 22 Ezekowitz MD, James KE, Nazarian SM. et al. Silent cerebral infarction in patients with nonrheumatic atrial fibrillation. The Veterans Affairs Stroke Prevention in Nonrheumatic Atrial Fibrillation Investigators. Circulation 1995; 92: 2178-2182.
• 23 Matsuo S, Nakamura Y, Kinoshita M. Warfarin reduces silent cerebral infarction in elderly patients with atrial fibrillation. Coron Artery Dis 1998; 09: 223-226.
• 24 Dagres N, Kottkamp H, Piorkowski C. et al. Influence of the duration of Holter monitoring on the detection of arrhythmia recurrences after catheter ablation of atrial fibrillation Implications for patient follow-up. Int J Cardiol. In press [Epub ahead of print] doi:10.1016/j.ijcard.2008.10.004.