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Is hyperuricemia a recognizable biomarker for low risk of stroke in patients with atrial fibrillation?
International Journal of Cardiology 203 (2016) 624–625
Contents lists available at ScienceDirect
International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard
Correspondence
Is hyperuricemia a recognizable biomarker for low risk of stroke in patients with atrial fibrillation? Yufan Yang, Qiming Liu ⁎, Zhihong Wu, Xuping Li, Ce Deng, Shenghua Zhou Cardiac Catheterization Lab of Second Xiangya Hospital attached to Central South University, No. 139 Middle Renmin Road, Changsha, Hunan 410011, People's Republic of China Department of Cardiology of Second Xiangya Hospital attached to Central South University, No. 139 Middle Renmin Road, Changsha, Hunan 410011, People's Republic of China
a r t i c l e
i n f o
Article history: Received 1 November 2015 Accepted 4 November 2015 Available online 5 November 2015 Keywords: Hyperuricemia Atrial fibrillation Stroke
Dear Editor We found the article on ‘The relationship between hyperuricemia and the risk of stroke in the patients with atrial fibrillation’ by Chao et al. [1] to be very interesting, in which hyperuricemia was demonstrated to be a high-risk factor for ischemia stroke in patients with atrial fibrillation. In addition, the incidence of ischemia stroke in hyperuricemia patients with CHA2DS2-VASc score of 0 was significantly higher than those without hyperuricemia, and anticoagulant drugs were recommended for atrial fibrillation patients with hyperuricemia and CHA2DS2-VASc score of 0. The investigation of stroke in low-risk patients by Chao et al. [1] has great clinical significance, and suggested the modification of current guidelines for anticoagulant treatment in patients with atrial fibrillation. CHA2DS2-VASc scale is a recently proposed method to evaluate the risk of stroke in patients with atrial fibrillation. It was adopted by ESC guideline in 2012 [2] and ACC/AHA atrial fibrillation management guideline in 2014 [3] as the only stratification scale, for stroke risk evaluation in patients with non-valvular atrial fibrillation receiving anticoagulant treatment. Is hyperuricemia a novel biomarker for stroke in patients with atrial fibrillation? Could hyperuricemia predict low risk of stroke in patients with atrial fibrillation? Some details in the article are quite confusing besides the limitation stated by Chao et al. Firstly, ⁎ Corresponding author at: Cardiac Catheterization Lab of Second Xiangya Hospital attached to Central South University, No. 139 Middle Renmin Road, Changsha, Hunan 410011, People's Republic of China. E-mail addresses: [email protected] (Y. Yang), [email protected] (Q. Liu).
http://dx.doi.org/10.1016/j.ijcard.2015.11.019 0167-5273/© 2015 Elsevier Ireland Ltd. All rights reserved.
hyperuricemia was defined as at least one onset of gout in patients who needed long-term administration of uric acid lowering medicines. So was there any difference in the incidence of stroke between patients with or without stable normal uric acid level? Secondly, both atrial fibrillation and hyperuricemia are high-risk factors for stroke; atrial fibrillation causes stroke due to embolism from thrombus detachment from left atrium/left atrial appendage [4], while hyperuricemia causes stroke due to the proliferation of vascular smooth muscle cells and the accelerated oxidation of low-density lipoprotein peroxidation, which leads to atherosclerotic plaque formation and embolism by the detached emboli [5]. Transesophageal echocardiography showing higher embolism rate in left atrial appendage of patients with hyperuricemia than those without hyperuricemia would be very convincing evidence. Thirdly, uric acid is known to have anti-oxidative effect [5,6], and the prognosis of stroke patients with elevated uric acid level was better than those with normal uric acid, implying that the effect of uric acid on stroke needs further investigation. Fourthly, atrial fibrillation patients were recruited within 10 years from January 2000 and December 31st 2009, the follow-up period was 3.0 ± 2.7 years, and only 14.7% patients had stroke during this period. So was any endpoint observed for the remaining 85.3% patients? For how long were these patients followed-up? Stroke in atrial fibrillation patients is known to be closely associated with disease course, and the longer the disease course, the higher is the risk of stroke. Therefore, the short follow-up duration in this study might have led to a biased conclusion. If the endpoint was not observed for 85.3% patients, then majority of the data was unknown in the current study, which would also lead to a biased conclusion. In summary, to investigate the possibility of hyperuricemia as a risk factor of stroke in atrial fibrillation patients, more rigorous clinical design is needed to exclude mixed influencing factors and avoid or reduce bias. Additionally, larger sample size, longer follow-up period, and more in-depth analysis are required before arriving at a definitive conclusion. Conflict of interest The authors report no relationships that could be construed as a conflict of interest. References [1] T.F. Chao, C.J. Liu, S.J. Chen, K.L. Wang, Y.J. Lin, S.L. Chang, et al., Hyperuricemia and the risk of ischemic stroke in patients with atrial fibrillation-could it refine clinical risk stratification in AF? Int J Cardiol 170 (2014) 344–349.
Correspondence [2] A.J. Camm, G.Y. Lip, R. De Caterina, I. Savelieva, D. Atar, S.H. Hohnloser, et al., ESC Committee for Practice Guidelines-CPG; Document Reviewers. 2012 focused update of the ESC guidelines for the management of atrial fibrillation: an update of the 2010 ESC guidelines for the management of atrial fibrillation- developed with the special contribution of the European heart rhythm association, Europace 14 (10) (2012) 1385–1413. [3] C.T. January, L.S. Wann, J.S. Alpert, H. Calkins, J.E. Cigarroa, J.C. Cleveland Jr., et al., American college of cardiology/American heart association task force on practice guidelines. 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: a report of the American college of cardiology/American heart. J Am Coll Cardiol 64 (21) (2014) e1–e76.
625
[4] M.C. Fang, A.S. Go, Y. Chang, M.C. Fang, A.S. Go, Y. Chang, et al., Comparison of risk stratification schemes to predict thromboembolism in people with nonvalvular atrial fibrillation, J Am Coll Cardiol 51 (8) (2008) 810–815. [5] R.C. Seet, K. Kasiman, J. Gruber, S.Y. Tang, M.C. Wong, H.M. Chang, et al., Is uric acid protective or deleterious in acute ischemic stroke? A prospective cohort study, Atherosclerosis 209 (2010) 215–219. [6] A. Chamorro, V. Obach, A. Cervera, M. Revilla, R. Deulofeu, J.H. Aponte, Prognostic significance of uric acid serum concentration in patients with acute ischemic stroke, Stroke 33 (2002) 1048–1052.
Contents lists available at ScienceDirect
International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard
Correspondence
Is hyperuricemia a recognizable biomarker for low risk of stroke in patients with atrial fibrillation? Yufan Yang, Qiming Liu ⁎, Zhihong Wu, Xuping Li, Ce Deng, Shenghua Zhou Cardiac Catheterization Lab of Second Xiangya Hospital attached to Central South University, No. 139 Middle Renmin Road, Changsha, Hunan 410011, People's Republic of China Department of Cardiology of Second Xiangya Hospital attached to Central South University, No. 139 Middle Renmin Road, Changsha, Hunan 410011, People's Republic of China
a r t i c l e
i n f o
Article history: Received 1 November 2015 Accepted 4 November 2015 Available online 5 November 2015 Keywords: Hyperuricemia Atrial fibrillation Stroke
Dear Editor We found the article on ‘The relationship between hyperuricemia and the risk of stroke in the patients with atrial fibrillation’ by Chao et al. [1] to be very interesting, in which hyperuricemia was demonstrated to be a high-risk factor for ischemia stroke in patients with atrial fibrillation. In addition, the incidence of ischemia stroke in hyperuricemia patients with CHA2DS2-VASc score of 0 was significantly higher than those without hyperuricemia, and anticoagulant drugs were recommended for atrial fibrillation patients with hyperuricemia and CHA2DS2-VASc score of 0. The investigation of stroke in low-risk patients by Chao et al. [1] has great clinical significance, and suggested the modification of current guidelines for anticoagulant treatment in patients with atrial fibrillation. CHA2DS2-VASc scale is a recently proposed method to evaluate the risk of stroke in patients with atrial fibrillation. It was adopted by ESC guideline in 2012 [2] and ACC/AHA atrial fibrillation management guideline in 2014 [3] as the only stratification scale, for stroke risk evaluation in patients with non-valvular atrial fibrillation receiving anticoagulant treatment. Is hyperuricemia a novel biomarker for stroke in patients with atrial fibrillation? Could hyperuricemia predict low risk of stroke in patients with atrial fibrillation? Some details in the article are quite confusing besides the limitation stated by Chao et al. Firstly, ⁎ Corresponding author at: Cardiac Catheterization Lab of Second Xiangya Hospital attached to Central South University, No. 139 Middle Renmin Road, Changsha, Hunan 410011, People's Republic of China. E-mail addresses: [email protected] (Y. Yang), [email protected] (Q. Liu).
http://dx.doi.org/10.1016/j.ijcard.2015.11.019 0167-5273/© 2015 Elsevier Ireland Ltd. All rights reserved.
hyperuricemia was defined as at least one onset of gout in patients who needed long-term administration of uric acid lowering medicines. So was there any difference in the incidence of stroke between patients with or without stable normal uric acid level? Secondly, both atrial fibrillation and hyperuricemia are high-risk factors for stroke; atrial fibrillation causes stroke due to embolism from thrombus detachment from left atrium/left atrial appendage [4], while hyperuricemia causes stroke due to the proliferation of vascular smooth muscle cells and the accelerated oxidation of low-density lipoprotein peroxidation, which leads to atherosclerotic plaque formation and embolism by the detached emboli [5]. Transesophageal echocardiography showing higher embolism rate in left atrial appendage of patients with hyperuricemia than those without hyperuricemia would be very convincing evidence. Thirdly, uric acid is known to have anti-oxidative effect [5,6], and the prognosis of stroke patients with elevated uric acid level was better than those with normal uric acid, implying that the effect of uric acid on stroke needs further investigation. Fourthly, atrial fibrillation patients were recruited within 10 years from January 2000 and December 31st 2009, the follow-up period was 3.0 ± 2.7 years, and only 14.7% patients had stroke during this period. So was any endpoint observed for the remaining 85.3% patients? For how long were these patients followed-up? Stroke in atrial fibrillation patients is known to be closely associated with disease course, and the longer the disease course, the higher is the risk of stroke. Therefore, the short follow-up duration in this study might have led to a biased conclusion. If the endpoint was not observed for 85.3% patients, then majority of the data was unknown in the current study, which would also lead to a biased conclusion. In summary, to investigate the possibility of hyperuricemia as a risk factor of stroke in atrial fibrillation patients, more rigorous clinical design is needed to exclude mixed influencing factors and avoid or reduce bias. Additionally, larger sample size, longer follow-up period, and more in-depth analysis are required before arriving at a definitive conclusion. Conflict of interest The authors report no relationships that could be construed as a conflict of interest. References [1] T.F. Chao, C.J. Liu, S.J. Chen, K.L. Wang, Y.J. Lin, S.L. Chang, et al., Hyperuricemia and the risk of ischemic stroke in patients with atrial fibrillation-could it refine clinical risk stratification in AF? Int J Cardiol 170 (2014) 344–349.
Correspondence [2] A.J. Camm, G.Y. Lip, R. De Caterina, I. Savelieva, D. Atar, S.H. Hohnloser, et al., ESC Committee for Practice Guidelines-CPG; Document Reviewers. 2012 focused update of the ESC guidelines for the management of atrial fibrillation: an update of the 2010 ESC guidelines for the management of atrial fibrillation- developed with the special contribution of the European heart rhythm association, Europace 14 (10) (2012) 1385–1413. [3] C.T. January, L.S. Wann, J.S. Alpert, H. Calkins, J.E. Cigarroa, J.C. Cleveland Jr., et al., American college of cardiology/American heart association task force on practice guidelines. 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: a report of the American college of cardiology/American heart. J Am Coll Cardiol 64 (21) (2014) e1–e76.
625
[4] M.C. Fang, A.S. Go, Y. Chang, M.C. Fang, A.S. Go, Y. Chang, et al., Comparison of risk stratification schemes to predict thromboembolism in people with nonvalvular atrial fibrillation, J Am Coll Cardiol 51 (8) (2008) 810–815. [5] R.C. Seet, K. Kasiman, J. Gruber, S.Y. Tang, M.C. Wong, H.M. Chang, et al., Is uric acid protective or deleterious in acute ischemic stroke? A prospective cohort study, Atherosclerosis 209 (2010) 215–219. [6] A. Chamorro, V. Obach, A. Cervera, M. Revilla, R. Deulofeu, J.H. Aponte, Prognostic significance of uric acid serum concentration in patients with acute ischemic stroke, Stroke 33 (2002) 1048–1052.