AUTHOR’S REPLY
Circulation Journal Official Journal of the Japanese Circulation Society http://www. j-circ.or.jp
Catheter Ablation of Atrial Fibrillation and Thromboembolic Risk – Reply – We thank Dr Kornej and coworkers for their interest in our paper and for raising important issues. Regarding the follow-up accuracy, annual telephone interviews with the patients and their families were conducted to confirm each patient’s hospitalization history for each year during our study.1 Thus, we are certain that we did not miss any patients with symptomatic thromboembolism (TE) who required hospitalization during the follow-up period. However, patients with transient ischemic attacks may have been missed if they did not visit a neurologist because of distance or timing reasons, did not visit a hospital because of symptom resolution, or if the attending physician deemed the symptom(s) sufficiently minor to make hospitalization unnecessary. We understand that the new European Society of Cardiology guidelines (2010) recommend the use of the CHA2DS2VASc score to complement initial assessments using the CHADS2 score.2 The CHA2DS2-VASc score is more inclusive of common stroke risk factors seen in everyday clinical practice, and an increasing number of studies support its use.3,4 However, unfortunately, we did not collect all relevant data to allow determination of the CHA2DS2-VASc score during this study because the guideline published in 2006 had recommended the use of the CHADS2 score.5 In contrast to previous studies regarding post-catheter ablation (CA) strokes, however, we performed detailed examinations of the 11 individuals who developed TE in the present study. Among them, 3 patients exhibited CHADS2 score ≤1 and 2 of those individuals showed CHA2DS2-VASc scores ≥2, one of them reaching a CHADS2 score of 2 and a CHA2DS2-VASc score of 3 at the time of the TE because she was over 75 years old. The remaining patient developed TE 4 years after the CA, at age 63 years, despite demonstrating low risk on both the CHADS2 (=0) and CHA2DS2-VASc (=0) score. However, this patient had underlying valvular heart disease. Despite the utility of scoring systems such as the CHADS2 and CHA2DS2-VASc, conditions specific to each individual also have to be taken into account, because tailor-made therapy may be important to the follow-up of post-CA atrial fibrillation (AF) patients. Hence, the TE risk should be reassessed as patients get older. Furthermore, in addition to the scores, each patient’s background should be carefully considered; for example, patients with cardiomyopathy,6,7 amyloidosis,8 low left atrial appendage flow velocity or spontaneous echo contrast on transesophageal echocardiography7,9 may have additional risks, even if they are in a lower risk group according to the scoring system. Moreover, the evidence of the value of these scoring systems for stroke risk stratification in patients with valvular heart disease has not been established.10 In addition, we should be very careful when discussing the post-CA predictors of TE. Although several factors are associated with late-phase TE, a low stroke incidence may decrease the statistical power and the results could easily change. AF recurrence, as a specific associated factor, should be dealt with carefully because the determination of AF recurrence itself is a limitation of AF ablation studies. AF recurrence may depend on the original type of AF (paroxysmal, persistent, or longstanding persistent), the presence or absence of symptoms or
medications, or the follow-up protocol. As well as Dr Kornej, we believe that AF recurrence might be an important predictor of late-phase TE, despite the weak statistical power of our study.1 However, further investigations involving large study populations and long and thorough follow-up are required to arrive at a definitive conclusion regarding this issue. Several studies have suggested that high-risk patients, categorized using risk scores, require optimized anticoagulation with intensified oral anticoagulation and/or intensified rhythm control. However, the optimized management for low-risk patients remains unknown and further studies are needed to elucidate these issues, as Dr Kornej mentioned. Disclosures None.
References 1. Takigawa M, Takahashi A, Kuwahara T, Takahashi Y, Okubo K, Nakashima E, et al. Late-phase thromboembolism after catheter ablation for paroxysmal atrial fibrillation. Circ J 2014; 78: 2394 – 2401. 2. Camm AJ, Kirchhof P, Lip GY, Schotten U, Savelieva I, Ernst S, et al. Guidelines for the management of atrial fibrillation: The Task Force for the Management of Atrial Fibrillation of the European Society of Cardiology (ESC). Europace 2010; 12: 1360 – 1420. 3. Potpara TS, Polovina MM, Licina MM, Marinkovic JM, Prostran MS, Lip GY. Reliable identification of “truly low” thromboembolic risk in patients initially diagnosed with “lone” atrial fibrillation: The Belgrade atrial fibrillation study. Circ Arrhythm Electrophysiol 2012; 5: 319 – 326. 4. Kornej J, Hindricks G, Kosiuk J, Arya A, Sommer P, Husser D, et al. Renal dysfunction, stroke risk scores (CHADS2, CHA2DS2VASc, and R2CHADS2), and the risk of thromboembolic events after catheter ablation of atrial fibrillation: The Leipzig Heart Center AF Ablation Registry. Circ Arrhythm Electrophysiol 2013; 6: 868 – 874. 5. Fuster V, Rydén LE, Cannom DS, Crijns HJ, Curtis AB, Ellenbogen KA, et al. ACC/AHA/ESC 2006 guidelines for the management of patients with atrial fibrillation: Executive summary. Circulation 2006; 114: 700 – 752. 6. Yamamoto K, Ikeda U, Furuhashi K, Irokawa M, Nakayama T, Shimada K. The coagulation system is activated in idiopathic cardiomyopathy. J Am Coll Cardiol 1995; 25: 1634 – 1640. 7. Yakar Tuluce S, Kayikcioglu M, Tuluce K, Yilmaz MG, Ozdogan O, Aydın M, et al. Assessment of left atrial appendage function during sinus rhythm in patients with hypertrophic cardiomyopathy: Transesophageal echocardiography and tissue Doppler study. J Am Soc Echocardiogr 2010; 23: 1207 – 1216. 8. Feng D, Edwards WD, Oh JK, Chandrasekaran K, Grogan M, Martinez MW, et al. Intracardiac thrombosis and embolism in patients with cardiac amyloidosis. Circulation 2007; 116: 2420 – 2426. 9. Lowe BS, Kusunose K, Motoki H, Varr B, Shrestha K, Whitman C, et al. Prognostic significance of left atrial appendage “sludge” in patients with atrial fibrillation: A new transesophageal echocardiographic thromboembolic risk factor. J Am Soc Echocardiogr 2014; 27: 1176 – 1183. 10. Hohnloser SH, Lopes RD. Atrial fibrillation, valvular heart disease, and use of target-specific oral anticoagulants for stroke prevention. Eur Heart J 2014 October 21, doi:10.1093/eurheartj/ehu386.
Masateru Takigawa, MD Atsushi Takahashi, MD Taishi Kuwahara, MD Kenzo Hirao, MD Mitsuaki Isobe, MD Cardiovascular Center, Yokosuka Kyosai Hospital, Yokosuka (M.T., A.T., T.K.); Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo (K.H.); and Department of Cardiovascular Medicine, Tokyo Medical and Dental University, Tokyo (M.T., M.I.), Japan
Circulation Journal Vol.79, February 2015
(Released online January 7, 2015)
Circulation Journal Official Journal of the Japanese Circulation Society http://www. j-circ.or.jp
Catheter Ablation of Atrial Fibrillation and Thromboembolic Risk – Reply – We thank Dr Kornej and coworkers for their interest in our paper and for raising important issues. Regarding the follow-up accuracy, annual telephone interviews with the patients and their families were conducted to confirm each patient’s hospitalization history for each year during our study.1 Thus, we are certain that we did not miss any patients with symptomatic thromboembolism (TE) who required hospitalization during the follow-up period. However, patients with transient ischemic attacks may have been missed if they did not visit a neurologist because of distance or timing reasons, did not visit a hospital because of symptom resolution, or if the attending physician deemed the symptom(s) sufficiently minor to make hospitalization unnecessary. We understand that the new European Society of Cardiology guidelines (2010) recommend the use of the CHA2DS2VASc score to complement initial assessments using the CHADS2 score.2 The CHA2DS2-VASc score is more inclusive of common stroke risk factors seen in everyday clinical practice, and an increasing number of studies support its use.3,4 However, unfortunately, we did not collect all relevant data to allow determination of the CHA2DS2-VASc score during this study because the guideline published in 2006 had recommended the use of the CHADS2 score.5 In contrast to previous studies regarding post-catheter ablation (CA) strokes, however, we performed detailed examinations of the 11 individuals who developed TE in the present study. Among them, 3 patients exhibited CHADS2 score ≤1 and 2 of those individuals showed CHA2DS2-VASc scores ≥2, one of them reaching a CHADS2 score of 2 and a CHA2DS2-VASc score of 3 at the time of the TE because she was over 75 years old. The remaining patient developed TE 4 years after the CA, at age 63 years, despite demonstrating low risk on both the CHADS2 (=0) and CHA2DS2-VASc (=0) score. However, this patient had underlying valvular heart disease. Despite the utility of scoring systems such as the CHADS2 and CHA2DS2-VASc, conditions specific to each individual also have to be taken into account, because tailor-made therapy may be important to the follow-up of post-CA atrial fibrillation (AF) patients. Hence, the TE risk should be reassessed as patients get older. Furthermore, in addition to the scores, each patient’s background should be carefully considered; for example, patients with cardiomyopathy,6,7 amyloidosis,8 low left atrial appendage flow velocity or spontaneous echo contrast on transesophageal echocardiography7,9 may have additional risks, even if they are in a lower risk group according to the scoring system. Moreover, the evidence of the value of these scoring systems for stroke risk stratification in patients with valvular heart disease has not been established.10 In addition, we should be very careful when discussing the post-CA predictors of TE. Although several factors are associated with late-phase TE, a low stroke incidence may decrease the statistical power and the results could easily change. AF recurrence, as a specific associated factor, should be dealt with carefully because the determination of AF recurrence itself is a limitation of AF ablation studies. AF recurrence may depend on the original type of AF (paroxysmal, persistent, or longstanding persistent), the presence or absence of symptoms or
medications, or the follow-up protocol. As well as Dr Kornej, we believe that AF recurrence might be an important predictor of late-phase TE, despite the weak statistical power of our study.1 However, further investigations involving large study populations and long and thorough follow-up are required to arrive at a definitive conclusion regarding this issue. Several studies have suggested that high-risk patients, categorized using risk scores, require optimized anticoagulation with intensified oral anticoagulation and/or intensified rhythm control. However, the optimized management for low-risk patients remains unknown and further studies are needed to elucidate these issues, as Dr Kornej mentioned. Disclosures None.
References 1. Takigawa M, Takahashi A, Kuwahara T, Takahashi Y, Okubo K, Nakashima E, et al. Late-phase thromboembolism after catheter ablation for paroxysmal atrial fibrillation. Circ J 2014; 78: 2394 – 2401. 2. Camm AJ, Kirchhof P, Lip GY, Schotten U, Savelieva I, Ernst S, et al. Guidelines for the management of atrial fibrillation: The Task Force for the Management of Atrial Fibrillation of the European Society of Cardiology (ESC). Europace 2010; 12: 1360 – 1420. 3. Potpara TS, Polovina MM, Licina MM, Marinkovic JM, Prostran MS, Lip GY. Reliable identification of “truly low” thromboembolic risk in patients initially diagnosed with “lone” atrial fibrillation: The Belgrade atrial fibrillation study. Circ Arrhythm Electrophysiol 2012; 5: 319 – 326. 4. Kornej J, Hindricks G, Kosiuk J, Arya A, Sommer P, Husser D, et al. Renal dysfunction, stroke risk scores (CHADS2, CHA2DS2VASc, and R2CHADS2), and the risk of thromboembolic events after catheter ablation of atrial fibrillation: The Leipzig Heart Center AF Ablation Registry. Circ Arrhythm Electrophysiol 2013; 6: 868 – 874. 5. Fuster V, Rydén LE, Cannom DS, Crijns HJ, Curtis AB, Ellenbogen KA, et al. ACC/AHA/ESC 2006 guidelines for the management of patients with atrial fibrillation: Executive summary. Circulation 2006; 114: 700 – 752. 6. Yamamoto K, Ikeda U, Furuhashi K, Irokawa M, Nakayama T, Shimada K. The coagulation system is activated in idiopathic cardiomyopathy. J Am Coll Cardiol 1995; 25: 1634 – 1640. 7. Yakar Tuluce S, Kayikcioglu M, Tuluce K, Yilmaz MG, Ozdogan O, Aydın M, et al. Assessment of left atrial appendage function during sinus rhythm in patients with hypertrophic cardiomyopathy: Transesophageal echocardiography and tissue Doppler study. J Am Soc Echocardiogr 2010; 23: 1207 – 1216. 8. Feng D, Edwards WD, Oh JK, Chandrasekaran K, Grogan M, Martinez MW, et al. Intracardiac thrombosis and embolism in patients with cardiac amyloidosis. Circulation 2007; 116: 2420 – 2426. 9. Lowe BS, Kusunose K, Motoki H, Varr B, Shrestha K, Whitman C, et al. Prognostic significance of left atrial appendage “sludge” in patients with atrial fibrillation: A new transesophageal echocardiographic thromboembolic risk factor. J Am Soc Echocardiogr 2014; 27: 1176 – 1183. 10. Hohnloser SH, Lopes RD. Atrial fibrillation, valvular heart disease, and use of target-specific oral anticoagulants for stroke prevention. Eur Heart J 2014 October 21, doi:10.1093/eurheartj/ehu386.
Masateru Takigawa, MD Atsushi Takahashi, MD Taishi Kuwahara, MD Kenzo Hirao, MD Mitsuaki Isobe, MD Cardiovascular Center, Yokosuka Kyosai Hospital, Yokosuka (M.T., A.T., T.K.); Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo (K.H.); and Department of Cardiovascular Medicine, Tokyo Medical and Dental University, Tokyo (M.T., M.I.), Japan
Circulation Journal Vol.79, February 2015
(Released online January 7, 2015)
