Skip to main content
Advertisement
Browse Subject Areas
?

Click through the PLOS taxonomy to find articles in your field.

For more information about PLOS Subject Areas, click here.

  • Loading metrics

Adjuvant Chinese Herbal Products for Preventing Ischemic Stroke in Patients with Atrial Fibrillation

  • Yu-Chiang Hung ,

    Contributed equally to this work with: Yu-Chiang Hung, Yu-Chen Cheng

    hungyuchiang@gmail.com (YCH); oolonghu@gmail.com (WLH)

    Affiliations Department of Chinese Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan, School of Chinese Medicine for Post Baccalaureate, I-Shou University, Kaohsiung, Taiwan

  • Yu-Chen Cheng ,

    Contributed equally to this work with: Yu-Chiang Hung, Yu-Chen Cheng

    Affiliation Department of Chinese Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan

  • Chih-Hsin Muo,

    Affiliation Management Office for Health Data, China Medical University Hospital, Taichung, Taiwan

  • Hsienhsueh Elley Chiu,

    Affiliation School of Chinese Medicine for Post Baccalaureate, I-Shou University, Kaohsiung, Taiwan

  • Chun-Ting Liu,

    Affiliation Department of Chinese Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan

  • Wen-Long Hu

    hungyuchiang@gmail.com (YCH); oolonghu@gmail.com (WLH)

    Affiliations Department of Chinese Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan, Kaohsiung Medical University College of Medicine, Kaohsiung, Taiwan, Fooyin University College of Nursing, Kaohsiung, Taiwan

Abstract

Objective

Chinese herbal products (CHPs) are widely used for atrial fibrillation (AF) in Taiwan. We investigated the effect of adjuvant CHPs in preventing ischemic stroke in patients with AF.

Methods

Taiwanese patients in the Health Insurance Database newly diagnosed with AF during 2000–2011 were enrolled. Medication treatment with/without CHPs was administered within 7 days after the AF diagnosis. The clinical endpoint was an ischemic stroke. The Chi-square test, Fisher’s exact test, and Student t test were used to examine differences between the traditional Chinese medicine (TCM) and non-TCM cohorts. Cox proportional hazard regression was used to assess the risk for ischemic stroke between two cohorts.

Results

Three hundred and eleven patients underwent TCM treatment and 1715 patients did not. Compared to non-TCM users, TCM users had a lower incidence of stroke (12.59% vs. 1.93%, respectively) and lower risk of stroke [CHA2DS2-VASc score = 0–2 (hazard ratio = 0.20; 95% confidence interval = 0.06–0.65)]. Compared to non-TCM users, the stroke risk was significantly lower in TCM users with AF who were female or younger than 65 years, but not in males, people more than 65 years old, or people with comorbidities. Compared to TCM users, non-TCM users who received conventional treatment had a higher ischemic stroke risk. The risk for AF-related hospitalization was significantly lower in TCM users (0.64%) than in non-TCM users (38.1%).

Conclusions

Users of TCM with AF have a lower risk of new-onset ischemic stroke. Therefore, adjuvant CHP therapy may have a protective effect and may be used in AF patients to prevent ischemic stroke.

Introduction

Atrial fibrillation (AF) is characterized by disorganized, rapid, and irregular atrial activation with loss of atrial contraction and an irregular ventricular rate that is determined by AV nodal conduction [1]. It is the most common arrhythmia and significantly increases stroke risk in adults. Some risk factors for stroke are hypertension, diabetes, and hyperlipidemia [2]. The incidence of AF increases with age, so more than 5% of adults older than 70 years will experience an AF [3]. In the Western world, AF affects approximately 1%–2% of the general population [4,5]. In the Chinese population, approximately 1.4% of men and 0.7% of women have an AF [6]. Common AF-associated complications are stroke, thromboembolism, and cardiomyopathy. Cardioembolism is responsible for approximately 20% of all ischemic strokes, and the most significant cause of cardioembolic stroke is nonrheumatic (i.e., nonvalvular) AF. Patients with AF have an average annual stroke risk of approximately 5%. The risk of stroke can be estimated by calculating the CHA2D2-VASc score, [7] also called the Birmingham 2009 scheme, which is obtained by assigning one point for each of the following factors: congestive heart failure, hypertension, age older than 75 years, diabetes mellitus, female, and vascular disease, while assigning two points for a history of stroke or transient ischemic attack. A CHA2DS2-VASc score of 2 or greater indicates a high risk. The relative risk of stroke for patients with AF is 1.8- to 2.9-fold [8]. Anticoagulation therapy is conventionally used to mitigate a possible stroke risk in patients with AF [9]. However, patients with AF under anticoagulation therapy might show a sudden onset of hemorrhagic stroke or an adverse effect such as gastrointestinal or urinary tract bleeding [10].

Traditional Chinese medicine (TCM) has been widely used in the Eastern world for thousands of years. Since 1995, Chinese herbal products (CHPs) have been listed under the National Health Insurance (NHI) program in Taiwan. Individual herbs such as Dan Shen (Salvia miltiorrhiza Bunge, rhizome) or herbal formulas such as zhi-gan-cao-tang (ZGCT; a multiple composition) are used to treat heart disease [11,12]. Whether adjuvant CHP therapy effectively prevents ischemic stroke in AF patients is still unclear. We investigated the effect of adjuvant CHP therapy on preventing ischemic strokes in patients with AF. We used a nationwide cohort containing nearly 100% Taiwanese residents who received health insurance from 2000 to 2011 in Taiwan.

Methods

Data resources

Since March 1995, Taiwan has implemented the NHI program. Until the end of 2014, approximately 99% of the total Taiwanese population had enrolled in the NHI program (NHI research database [NHIRD]; http://nhird.nhri.org.tw/en/). The Bureau of NHI (BNHI) is contracted with 97% of hospitals and clinics throughout the nation [13]. The database provides a representative sample of data, and includes some medical information for several years and keeps track of the people whose details are entered into the sample files.

Longitudinal Health Insurance Database 2000 (LHID2000) includes information for 1 million people. The identification of insurants in the LHID2000 was recoded before being sent to researchers because of the Personal Information Protection Act. This study was approved by the Institutional Review Board of China Medical University in Central Taiwan (CMU-REC-101-012).

Study population

We collected the data for 14,415 patients with newly diagnosed AF (ICD-9-CM codes 427.31 and 427.89) from the LHID during 2000–2011. Patients with AF were excluded if they had a history of stroke (based on the International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM] codes 430–438), were younger than 20 years, or had undergone medication treatment more than 7 days after the date of the AF diagnosis. Medication treatment was administered with/without CHPs within 7 days after the date of the AF diagnosis. AF patients were grouped into the TCM cohort (i.e., CHPs and conventional treatment) or the non-TCM cohort (i.e., conventional treatment only). The endpoint was an ischemic stroke (ICD-9-CM codes 433–438) or the end of 2011. (Fig 1)

thumbnail
Fig 1. Flow chart of the study participants.

AF, atrial fibrillation; LHID, Longitudinal Health Insurance Database; TCM, traditional Chinese medicine.

https://doi.org/10.1371/journal.pone.0159333.g001

Potential risk factors included hypertension (ICD-9-CM codes 401–405), diabetes (ICD-9-CM code 250), hyperlipidemia (ICD-9-CM code 272), congestive heart failure (CHF; ICD-9-CM codes 428, 402.01, 402.11, 402.91, 404.01, 404.11, and 404.91), and ischemic heart disease (ICD-9-CM codes 410–414, 443.89, 443.9 and 444). Complications of bleeding included hemorrhagic stroke (ICD-9-CM codes 430–432) and gastrointestinal bleeding (ICD-9-CM code 578). All risk factors were defined before the date of the AF diagnosis.

Statistical analysis

All analyses used SAS software, version 9.3 (SAS Institute, Cary, NC). The statistical significance level was P<0.05 (two-tailed). The Chi-square test was used to test differences between the TCM and non-TCM cohorts, based on sex, age (i.e., younger than 65 years or 65 years and older), comorbidities, and one complication (e.g., gastrointestinal bleeding). Fisher’s exact test was used to test the differences between the two cohorts for another complication (i.e., hemorrhagic stroke). The Student t test was used to test the difference between the two cohorts in the mean age and CHA2DS2-VASc score. Person-years were counted in each cohort from the index date to the date of ischemic stroke (ICD-9-CM codes 433–437). Patients who did not have a stroke were followed until the date they withdrew from the program or the end of 2011, whichever was first. For each cohort, the ischemic stroke incidence was calculated by the number of ischemic strokes divided by person-years. The number of person-years was calculated by summing the number of years from the index date to the date of endpoint. Cox proportional hazard regression was used to assess the risk for ischemic stroke in the TCM cohort in comparison to the non-TCM cohort. Model 1 was adjusted for continuous age, sex, and all comorbidities. Model 2 was adjusted for the CHA2DS2-VASc score. Risks specific for age, sex, comorbidities, and CHA2DS2-VASc score were estimated. The association between ischemic stroke and different medication treatments was assessed. We also estimated the risk of emergency room (ER) visits and hospitalization due to AF within 1 year after the index date in TCM users, compared to non-TCM users in logistical regression. In the sensitivity test, we selected two subgroups of non-TCM users from the original non-TCM cohort. The first non-TCM subgroup was matched by age, sex, and comorbidity according to propensity score. The second non-TCM subgroup was matched by the propensity score, which was calculated by logistical regression, based on the CHA2DS2-VASc score (S1S4 Tables).

Results

We enrolled 2026 AF patients: 311 patients with CHP treatment and 1715 patients without CHP treatment. Patients in the TCM cohort, compared to the non-TCM cohort, were more often women (75.9% [n = 236] vs. 44.5% [n = 763], respectively), younger (49.4±14.3 years vs. 65.0±14 years), and had fewer comorbidities and complications such as hypertension (27.7% vs. 66.8%), diabetes (6.43% vs. 18.0%), ischemic heart disease (19.0% vs. 53.2%), CHF (1.93% vs. 24.1%), hemorrhagic stroke (0.32% vs. 2.68%), and gastrointestinal bleeding (4.5% vs. 12.8%) (Table 1). There was no difference between the two cohorts in the prevalence of hyperlipidemia. The mean CHA2DS2-VASc score was lower in the TCM users (1.49±1.11) than in the non-TCM users (2.88±1.68).

thumbnail
Table 1. The Comorbidities, CHA2DS2-Vasc Scores, and Complications between the TCM and Non-TCM Groups.

https://doi.org/10.1371/journal.pone.0159333.t001

During the mean 5.17 follow-up-year period, the incidence of ischemic stroke was lower in the TCM cohort (5.25/1000 person-years) than in the non-TCM cohort (23.14/1000 person-years) (Table 2). After adjusting for age, sex, and comorbidities, the hazard ratio for ischemic stroke was significant at 0.39 (95% CI = 0.17–0.90). The other adjusted CHA2DS2-VASc score for ischemic stroke was 0.33 (95% CI = 0.15–0.75). The TCM users had a significantly lower risk of stroke, compared to non-TCM users who were women [HR = 0.20 (95% CI = 0.17–0.90) in model 1; HR = 0.19 (95% CI = 0.05–0.83) in model 2] or younger than 65 years [HR = 0.10 (95% CI = 0.01–0.07) in model 1; HR = 0.09 (95% CI = 0.01–0.63) in model 2]. In addition, TCM users had a significantly lower ischemic stroke risk [HR = 0.20 (95%CI = 0.06–0.65)] than non-users in patients with a CHA2DS2-VASc score of 0–2. There were no significant differences between patients who were male, older than 65 years, had comorbidities, and a CHA2DS2-VASc score > 2. In the sensitivity analyses, TCM users and non-TCM users had the same trends, regardless of which matched criteria were used.

thumbnail
Table 2. The Incidence and Hazard Ratios for Ischemic Stroke in the TCM Cohort, Compared to the Non-TCM Cohort.

https://doi.org/10.1371/journal.pone.0159333.t002

The proportion of AF-related ER visits within 1 year after the AF diagnosis was lower in TCM users than in non-users (14.5% vs. 15.3%, respectively; odds ratio, 0.94 in model 1 and 0.87 in model 2). The risk for AF-related hospitalization within 1 year of diagnosis was also significantly lower in TCM users (0.64%) than in non-users (38.1%) (odds ratio, 0.01 in model 1 and 0.02 in model 2) (Table 3). The top three combined diseases responsible for AF-related hospitalization were heart failure (10.1%), ischemic heart disease (10.1%), and diabetes (5.5%). The top three combined diseases responsible for AF-related ER visits were heart failure (13.7%), ischemic heart disease (12.7%), and symptoms involving the cardiovascular system (5.86%). The annual total medical cost was 1988 NTD (New Taiwan Dollar) and 61310 NTD in TCM and non-TCM cohort during the study period. The most common formula and single CHPs used for AF treatment in Taiwan were ZGCT (5.42%; Table 4) and Dan Shen (3.95%; Table 4).

thumbnail
Table 3. The Odds Ratio for Emergency Room Visits and Hospitalization due to Atrial Fibrillation within 1 Year after the Index Date in the TCM Cohort, Compared to the Non-TCM Cohort.

https://doi.org/10.1371/journal.pone.0159333.t003

thumbnail
Table 4. The top 5 single and formula CHPs prescribed by TCM physicians for treating patients with AF from 2000 to 2010 in Taiwan.

https://doi.org/10.1371/journal.pone.0159333.t004

Discussion

In this nationwide cohort analysis, we showed that adjuvant CHP therapy could reduce the incidence of new ischemic stroke in AF patients who are female, younger than 65 years, and have a CHA2DS2-VASc score less than 2 (i.e. low risk for ischemic stroke). A previous study showed that female patients with AF and a CHA2DS2-VASc score of 1 had a higher risk for ischemic events, compared to non-AF patients [14]. Some researchers have found a lower incidence of stroke in pre- menopausal women, but a higher incidence of stroke in post-menopausal women compared with men. This phenomenon may be due to the potential neuroprotective benefits of hormones, most notably estrogen [15,16]. However, estrogen had no dominant effects in female patients with AF. They have been noted to have greater thromboembolic risk than male patients with AF [17,18], which may result from biological factors, including increased hypertension, renal dysfunction, and hyperthyroidism, in female patients with AF. Our results showed that patients with AF in the TCM cohort, compared to the non-TCM cohort, were more often women (75.9% [n = 236] vs. 44.5% [n = 763]). Female patients with AF in the TCM group having lower risk of stroke than male patients with AF may be due to a stronger response to integrated TCM and conventional Western medicine. (TCM group were treated with TCM and conventional Western medicine; non-TCM group were only treated with conventional Western medicine). The other result also showed there were more younger patients with AF in the TCM cohort than in the non-TCM cohort (49.4±14.3 years vs. 65.0±14 years). A previous study found age-related changes in brain support cells [19]. Younger patients with AF may have fewer comorbidities and a stronger response to integrated TCM and conventional Western medicine. These results could also support the benefit of adjuvant CHP therapy in our study. We also found in the non-TCM cohort that the greater the number of medications, the higher was the incidence of stroke. Multiple medications to treat AF may indicate a greater severity of AF.

A previous cohort study revealed that approximately one in eight users of western medicine (e.g., antiplatelets, anticoagulants, or digoxin) was concomitantly prescribed CHPs in the Taiwanese population [20]. In our study, the most used single CHP and formula CHP in AF patients were Dan Shen (Salvia miltiorrhiza Bunge, rhizome) and ZGCT, respectively. Dan Shen is a very versatile Chinese herbal drug that has been used for hundreds of years to treat ailments such as cardiovascular diseases [21,22]. Pharmacological studies indicate that Dan Shen acts against atherosclerotic vascular disease by inhibiting smooth muscle proliferation [23,24], and is used for dilating the cardiocerebral vessels, suppressing the aggregation of platelets, activating circulation, dispersing blood stasis, protecting from ischemic reperfusion injury, and enhancing the tolerance of ischemic tissue to hypoxia [25,26]. In a recent Chinese study, Dan Shen reduced the incidence of arrhythmias from 30% to 18% [27]. Dan Shen has also been used as a standard treatment clinically for cerebrovascular diseases, which include stroke. The neuroprotective mechanisms of Dan Shen through antiapoptotic, anti-oxidant, anti-inflammatory effects were predicted by several studies [28]. However, some systematic reviews of randomized controlled trials failed to support its efficacy in improving disability after ischemic stroke [29,30]. Nevertheless, these results may be because of the unclear methodological quality of these identified trials [31].

For thousands of years in the Chinese community, ZGCT has been a representative formula to treat arrhythmia in patients with a knotted irregular pulse and severe palpitations [32]. Several clinical trials show that ZGCT may improve heart palpitations, shortness of breath, insomnia, and fatigue in patients with premature ventricular contractions [33]. In Taiwan, ZGCT is widely used alone or in combination with antiarrhythmic drugs as an alternative, effective treatment for AF. The possible mechanisms of frequently used CHPs (single and formula) for AF are presented in Table 5.

thumbnail
Table 5. Possible mechanisms of frequently used CHPs for AF from 2000 to 2010 in Taiwan.

https://doi.org/10.1371/journal.pone.0159333.t005

Dan Shen may interact with the anticoagulant action of warfarin. Patients receiving warfarin therapy may show gross overanticoagulation and bleeding complications when taking Dan Shen [60]. Dan Shen may be able to bind with warfarin to affect its absorption [61]. Some review articles have listed many CHPs that interact with warfarin by influencing absorption, metabolizing enzymes, protein binding, platelet function, vitamin K cycle, or coagulation cascade [62,63]. Thus, it is necessary to have an interval of 1 hour between taking CHPs and taking a Western medication. It is important to monitor the prothrombin time or the international normalized ratio in these patients.

After ischemic stroke or transient ischemic attack, a patient should not have oral anticoagulants combined with antiplatelet therapy. The most recent advice by the American Heart Association for treating stroke in AF patients proposes this. However, this treatment is reasonable in patients with clinically apparent coronary artery disease, particularly patients with acute coronary syndrome or stent placement [64]. We excluded patients with a previous stroke history in this cohort; however, the prevention of new onset ischemic stroke on AF patients using CHPs was significant. Our results suggested that TCM reduces the severity of AF, which subsequently reduces the risk of stroke and were consistent with previous reports in which adjuvant CHP medication demonstrated favorable circulatory system outcomes [65]. Therefore, adjuvant CHP therapy may be a choice for patients who are unsuitable for oral anticoagulation with antiplatelet therapy.

Our study has several limitations. First, the non-TCM users may have received other complementary therapies during the study. The TCM data from our NHI database is confined to CHPs. Herbal decoctions were not recorded in the database. Second, the TCM users may have received acupuncture therapy during the treatment. Several studies show acupuncture has positive effects on heart rate control. The acupuncture point, PC-6 (Pericardium-6; “Neiguan” in modern Chinese language), is involved in controlling arrhythmias [6669]. Third, lifestyle-related information such as data on drinking, weight, or smoking status in this cohort was lacking. Fourth, as we discussed previously, there were still some risks of bleeding and adverse effects when we combined CHPs with warfarin, which promotes blood circulation and removes blood stasis. The data for the risk of bleeding and adverse effects in this cohort was lacking. Fifth, the coagulation function and percentage of AF ablation between TCM and non-TCM users were not available in LHID. It was unlikely that we could provide the data on AF burden.

Conclusions

In this cohort study, TCM users had a lower risk of new onset ischemic stroke and lower hospitalization within 1 year, compared to non-TCM users. Therefore, adjuvant CHPs therapy may be used in AF patients to prevent ischemic stroke.

Supporting Information

S1 Table. Distribution for demographic characteristic between TCM and non-TCM cohort after propensity score matching.

https://doi.org/10.1371/journal.pone.0159333.s001

(DOCX)

S2 Table. Incidence and hazard ratio for ischemic stroke in TCM cohort compared with non-TCM cohort after propensity score matching.

https://doi.org/10.1371/journal.pone.0159333.s002

(DOCX)

S3 Table. Odds ratio for ER and hospitalization due to AF within one year after index date in TCM cohort compared with non-TCM cohort in logistic regression.

https://doi.org/10.1371/journal.pone.0159333.s003

(DOCX)

S4 Table. The Incidence and Hazard Ratios for Ischemic Stroke among the Different Treatments.

https://doi.org/10.1371/journal.pone.0159333.s004

(DOCX)

Acknowledgments

We thank Prof Chung Y. Hsu for his enthusiastic help in this work.

Author Contributions

Conceived and designed the experiments: YCH WLH. Performed the experiments: YCH WLH YCC CHM. Analyzed the data: CHM. Contributed reagents/materials/analysis tools: CHM. Wrote the paper: YCH WLH YCC CHM. Critically reviewed the manuscript: HEC CTL.

References

  1. 1. Michaud GF, Stevenson WG. Supraventricular Tachyarrhythmias. In: Kasper D, Fauci A, Hauser S, Longo D, Jameson J, Loscalzo J. eds. Harrison's Principles of Internal Medicine, 19th Ed. New York, NY: McGraw-Hill; 2015. Available: http://accessmedicine.mhmedical.com/content.aspx?bookid=1130&Sectionid=79742251. Accessed 20 March 2016.
  2. 2. Tsai CF, Anderson N, Thomas B, Sudlow CL. Risk factors for ischemic stroke and its subtypes in Chinese vs. Caucasians: Systematic review and meta-analysis. Int J Stroke. 2015;10:485–93. pmid:25907735
  3. 3. Marchlinski F. The Tachyarrhythmias. In: Longo DL, Fauci AS, Kasper DL, Hauser SL, Jameson J, Loscalzo J, eds, 2012. Harrison's Principles of Internal Medicine, 18th Ed. New York, NY: McGraw-Hill. Available: http://accessmedicine.mhmedical.com/content.aspx?bookid=331&Sectionid=40727006. Accessed 28 February 2015.
  4. 4. Go AS, Hylek EM, Phillips KA, Chang Y, Henault LE, Selby JV, et al. Prevalence of diagnosed atrial fibrillation in adults: national implications for rhythm management and stroke prevention: the Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA) Study. JAMA. 2001;285: 2370–2375. pmid:11343485
  5. 5. Pellman J, Sheikh F. Atrial fibrillation: mechanisms, therapeutics, and future directions. Compr Physiol. 2015;5:649–665. pmid:25880508
  6. 6. Chien KL, Su TC, Hsu HC, Chang WT, Chen PC, Chen MF, et al. Atrial fibrillation prevalence, incidence and risk of stroke and all-cause death among Chinese. Int J Cardiol. 2010;139: 173–180. pmid:19046608
  7. 7. Lip GYH, Nieuwlaat R, Pisters R, Lane DA, Crijns HJGM. Refining clinical risk stratification for predicting stroke and thromboembolism in atrial fibrillation using a novel risk factor-based approach: the Euro Heart Survey on atrial fibrillation. Chest. 2010;1372: 263–272. pmid:19762550
  8. 8. Smith WS, English JD, Johnston SC. Cerebrovascular Diseases. In: Longo DL, Fauci AS, Kasper DL, Hauser SL, Jameson J, Loscalzo J, eds, 2012. Harrison's Principles of Internal Medicine, 18th Ed. New York, NY: McGraw-Hill. Available: http://accessmedicine.mhmedical.com/content.aspx?bookid=331&Sectionid=40727186. Accessed 28 February 2015.
  9. 9. You JJ, Singer DE, Howard PA, Lane DA, Eckman MH, Fang MC, et al. Antithrombotic therapy for atrial fibrillation: antithrombotic therapy and prevention of thrombosis, 9th Ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141: e531S–e575S. pmid:22315271
  10. 10. Ageno W, Gallus AS, Wittkowsky A, Crowther M, Hylek EM, Palareti G. Oral anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th Ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141: e44S–e88S. pmid:22315269
  11. 11. Liu W, Xiong X, Feng B, Yuan R, Chu F, Liu H. Classic herbal formula Zhigancao Decoction for the treatment of premature ventricularcontractions (PVCs): A systematic review of randomized controlled trials. Complementary Therapies in Medicine. 2015;23: 100–115. pmid:25637158
  12. 12. Chen LY, Chen Q, Liu RH, Bi M, Zhou LJ, Wen H. Studies on effect of main active principles in ZHIGANCAO DECOCTION on myocardial electrophysiology. Chinese Traditional and Herbal Drugs. 2001;32: 134–136.
  13. 13. Chiang TL, 1997. Taiwan's 1995 health care reform. Health Policy. 39, 225–239. pmid:10165463
  14. 14. Chao TF, Liu CJ, Chen SJ, Wang KL, Lin YJ, Chang SL, et al. Atrial fibrillation and the risk of ischemic stroke: does it still matter in patients with a CHA2DS2-VASc score of 0 or 1? Stroke. 2012;43: 2551–2555. pmid:22871677
  15. 15. Koellhoffer EC, McCullough LD. The effects of estrogen in ischemic stroke. Transl Stroke Res. 2013;4:390–401. pmid:24323337
  16. 16. Liu R, Yang SH. Window of opportunity: estrogen as a treatment for ischemic stroke. Brain Res. 2013;1514:83–90. pmid:23340160
  17. 17. Cheng EY, Kong MH. Gender differences of thromboembolic events in atrial fibrillation. Am J Cardiol. 2016;117:1021–7. pmid:26923085
  18. 18. Cove CL, Albert CM, Andreotti F, Badimon L, Van Gelder IC, Hylek EM. Female sex as an independent risk factor for stroke in atrial fibrillation: possible mechanisms. Thromb Haemost. 2014;111:385–91. pmid:24305974
  19. 19. Sohrabji F, Bake S, Lewis DK. Age-related changes in brain support cells: Implications for stroke severity.Neurochem Int. 2013;63:291–301. pmid:23811611
  20. 20. Tsai HH, Lin HW, Chien CR, Li TC. Concurrent use of antiplatelets, anticoagulants, or digoxin with Chinese medications: a population-based cohort study. Eur J Clin Pharmacol. 2013;69: 629–639. pmid:22875040
  21. 21. Cheng TO. Danshen: a versatile Chinese herbal drug for the treatment of coronary heart disease. Int J Cardiol.2006;113: 437–438 pmid:16338013
  22. 22. Cheng TO. Cardiovascular effects of Danshen. Int J Cardiol. 2007;121: 9–22. pmid:17363091
  23. 23. Hung YC, Wang PW, Pan TL. Functional proteomics reveal the effect of Salvia miltiorrhiza aqueous extract against vascular atherosclerotic lesions. Biochim Biophys Acta. 2010;1804: 1310–1321. pmid:20170756
  24. 24. Hung YC, Wang PW, Pan TL, Bazylak G, Leu YL. Proteomic screening of antioxidant effects exhibited by radix Salvia miltiorrhiza aqueous extract in cultured rat aortic smooth muscle cells under homocysteine treatment. J Ethnopharmacol. 2009;124: 463–474. pmid:19481143
  25. 25. Chinese Materia Medical Compiling Committee of the National Administration Bureau of Traditional Chinese Medicine. Radix Salviae Miltiorrhizae. 1998. Chinese Materia Medica.: Shanghai Science and Technology Press. pp.1654–1663.
  26. 26. Li JL, Liu H. Compound Dan Shen Injection for noncardiocerebrovascular diseases. Research of Traditional Chinese Medicine. 2000;16: 57–58.
  27. 27. Qiu ZX, Ma HJ, Wang DF. Observation on effect of compound Danshen droplet-pill combined with trimetazidine in treating senile unstable angina pectoris. Zhongguo Zhong Xi Yi Jie He Za Zhi. 2005;25: 787–789 pmid:16248238
  28. 28. Bonaccini L, Karioti A, Bergonzi MC, Bilia AR. Effects of Salvia miltiorrhiza on CNS Neuronal Injury and Degeneration: A Plausible Complementary Role of Tanshinones and Depsides. Planta Med. 2015;81:1003–16. pmid:26190397
  29. 29. Wu B, Liu M, Liu H, Li W, Tan S, Zhang S, et al. Meta-analysis of traditional Chinese patent medicine for ischemic stroke. Stroke. 2007;38: 1973–1979. pmid:17463317
  30. 30. Sze FK, Yeung FF, Wong E, Lau J. Does Danshen improve disability after acute ischaemic stroke? Acta Neurol Scand. 2005;111: 118–125 pmid:15644072
  31. 31. Wu B, Liu M, Zhang S. Dan Shen agents for acute ischaemic stroke. Cochrane Database of Systematic Reviews. 2007 Apr 18;(2):CD004295. pmid:17443544
  32. 32. Chen WG, Ba ZM. Prof. ZHANG Yi's experience in treating severe arrhythmia. J Tradit Chin Med. 2010;30: 47–50. pmid:20397463
  33. 33. Wang B. The effect of Zhi Gan Cao Decoction on frequent premature ventricular contractions. J Pract Tradit Chin Med. 2013;29: 168.20.
  34. 34. Tsai DS, Chang YS, Li TC, Peng WH. Prescription pattern of Chinese herbal products for hypertension in Taiwan: a population-based study. J Ethnopharmacol. 2014;155: 1534–40. pmid:25091464
  35. 35. Tsai TF. Meridian Related Myocardial Infarction- A Case Report. Taiwan Journal of Clinical Chinese Medicine. 2008;14:308–15.
  36. 36. Chen LC, Wang BR, Chen IC, Shao CH. Use of Chinese herbal medicine among menopausal women in Taiwan. Int J Gynaecol Obstet. 2010;109: 63–66. pmid:19969298
  37. 37. Zhou X. Tianwang Buxin Mini-pills in the Treatment of Premature Ventricular Contractions(Hyperactivity of Fire due to Yin Deficiency Type) for 46 Cases. Chinese Medicine Modern Distance Education of China. 2015;12:50–51.[Article in Chinese]
  38. 38. Liu SJ, Zhou YL. Ningxin Anshen Fang, Ciwujia Joint Tianwangbuxin Treating Cardiovascular Neurosis Randomized Controlled Study. Journal of Practical Traditional Chinese Internal Medicine. 2015;8:7–8. [Article in Chinese]
  39. 39. Chen Q. Pharmacological and Clinical Basis of Renowned Patent Traditional Chinese Medicines: Pharmacology and Clinical Applications, People's Medical Publishing House, Beijing, China. (1998), p. 382
  40. 40. Qin RA, Yao XX, Huang ZY. Effects of compound danshen tablets on spatial cognition and expression of brain beta-amyloid precursor protein in a rat model of Alzheimer's disease. J Tradit Chin Med. 2012;32:63–6. pmid:22594104
  41. 41. Ren-an Q, Juan L, Chuyuan L, et al. Study of the protective mechanisms of Compound Danshen Tablet (Fufang Danshen Pian) against myocardial ischemia/reperfusion injury via the Akt-eNOS signaling pathway in rats. J Ethnopharmacol. 2014;156:190–8. pmid:25178948
  42. 42. Li J, Jai G. Clinical Applicational Situation of Qingxin Lianzi Decoction in Kidney Disease. Journal of Liaoning University of TCM. 2009;11:83–4. [Article in Chinese]
  43. 43. Chu FY, Wang J, Yao KW, Li ZZ. Effect of Xuefu Zhuyu Capsule (血府逐瘀胶囊) on the symptoms and signs and health-related quality of life in the unstable angina patients with blood-stasis syndrome after percutaneous coronary intervention: a randomized controlled trial. Chin. J. Integr. Med. 2010;16: 399–405 pmid:20535581
  44. 44. Lee JJ, Hsu WH, Yen TL, Chang NC, Luo YJ, Hsiao G, et al. Traditional Chinese medicine, Xue-Fu-Zhu-Yu decoction, potentiates tissue plasminogen activator against thromboembolic stroke in rats. J Ethnopharmacol. 2011;134: 824–30. pmid:21315142
  45. 45. Wu CJ, Chen JT, Yen TL, Jayakumar T, Chou DS, Hsiao G, et al. Neuroprotection by the Traditional Chinese Medicine, Tao-Hong-Si-Wu-Tang, against Middle Cerebral Artery Occlusion-Induced Cerebral Ischemia in Rats. Evid Based Complement Alternat Med. 2011;2011:803015. pmid:21076527
  46. 46. Chen FY, Guo R, Zhang BK. Advances in cardiovascular effects of tanshinone II(A). Zhongguo Zhong Yao Za Zhi. 2015;40:1649–53. [Article in Chinese] pmid:26323123
  47. 47. Xu KD, Chang YX, Zhang J, Wang PL, Wu JX, Li YY, et al. A lower pH value benefits regeneration of Trichosanthes kirilowii by somatic embryogenesis, involving rhizoid tubers (RTBs), a novel structure. Sci Rep. 2015;5:8823. pmid:25744384
  48. 48. Zhou W, Wang Y. A network-based analysis of the types of coronary artery disease from traditional Chinese medicine perspective: potential for therapeutics and drug discovery. J Ethnopharmacol. 2014; 151:66–77. pmid:24269247
  49. 49. Liu P, Hu Y, Guo DH, Wang DX, Tu HH, Ma L, et al. Potential antidepressant properties of Radix Polygalae (Yuan Zhi). Phytomedicine. 2010;17: 794–9. pmid:20541923
  50. 50. Tian H, Xu X, Zhang F, Wang Y, Guo S, Qin X, et al. Analysis of Polygala tenuifolia Transcriptome and Description of Secondary Metabolite Biosynthetic Pathways by Illumina Sequencing. Int J Genomics. 2015;2015:782635. pmid:26543847
  51. 51. Nagajyothi PC, Cha SJ, Yang IJ, Sreekanth TV, Kim KJ, Shin HM. Antioxidant and anti-inflammatory activities of zinc oxide nanoparticles synthesized using Polygala tenuifolia root extract. J Photochem Photobiol B. 2015;146:10–7. pmid:25777265
  52. 52. Shia CS, Tsai SY, Lin JC, Li ML, Ko MH, Chao PD, et al. Steady-state pharmacokinetics and tissue distribution of anthraquinones of Rhei Rhizoma in rats. J. Ethnopharmacol. 2011;137: 1388–1394. pmid:21855620
  53. 53. Cai Y, Sun M, Xing J, Corke H. Antioxidant phenolic constituents in roots of Rheum officinale and Rubia cordifolia: structure–radical scavenging activity relationships. J Agric Food Chem. 2004;52:7884–90. pmid:15612771
  54. 54. Lu L, Guan QX, Tian YX, Lin JX, Liang SW, Wang SM. Simulation and Prediction of Material Foundation of Rhei Radix et Rhizoma for Ischemic Stroke Based on Molecular Docking Technology. Zhong Yao Cai. 2015;38:781–5. pmid:26672347 [Article in Chinese]
  55. 55. Sim Y, Oh H, Oh DS, Kim N, Gu PS, Choi JG, et al. An experimental study on providing a scientific evidence for seven-time alcohol-steaming of Rhei Rhizoma when clinically used. BMC Complement Altern Med. 2015;15:388. pmid:26506837
  56. 56. Xiao Y, Liu YY, Yu KQ, Ouyang MZ, Luo R, Zhao XS. Chinese herbal medicine liu jun zi tang and xiang sha liu jun zi tang for functional dyspepsia: meta-analysis of randomized controlled trials. Evid Based Complement Alternat Med. 2012;2012: 936459. pmid:23304226
  57. 57. Chinese Pharmacopoeia Commission Pharmacopoeia of the People's Republic of China (Volume 1). China: China Medical Science and Technology Press. 2010. pp 236–237.
  58. 58. Tang JY, Liu FJ, Su MX, Huang SF, Chen JY,Chen QX. Study on Antioxidant and Antimicrobial Effects of extract from Amomum villosum. Journal of Xiamen University(Natural Science). 2012;4:789–92.
  59. 59. Zhang D, Li S, Xiong Q, Jiang C, Lai X. Extraction, characterization and biological activities of polysaccharides from Amomum villosum. Carbohydr Polym. 2013;95:114–22. pmid:23618247
  60. 60. Chan Thomas YK. Interaction between warfarin and danshen (Salvia miltiorrhiza). Ann Pharmacother. 2001;35: 501–504. pmid:11302416
  61. 61. Nutescu EA, Shapiro NL, Ibrahim S, West P. Warfarin and its interactions with foods, herbs and other dietary supplements. Expert Opin Drug Saf. 2006; 5:433–51. pmid:16610971
  62. 62. Ge B, Zhang Z, Zuo Z. Updates on the clinical evidenced herb-warfarin interactions. Evid Based Complement Alternat Med. 2014;2014:957362. pmid:24790635
  63. 63. Chua YT, Ang XL, Zhong XM, Khoo KS. Interaction between warfarin and Chinese herbal medicines. Singapore Med J. 2015;56:11–8. pmid:25640094
  64. 64. Kernan WN, Ovbiagele B, Black HR, Bravata DM, Chimowitz MI, Ezekowitz MD, et al. Guidelines for the prevention of stroke in patients with stroke and transient ischemic attack: a guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke. 2014;45: 2160–2236. pmid:24788967
  65. 65. Chiu HE, Hong YC, Chang KC, Shih CC, Hung JW, Liu CW, et al. Favorable circulatory system outcomes as adjuvant traditional Chinese medicine (TCM) treatment for cerebrovascular diseases in Taiwan. PLoS One. 2014;9: e86351. pmid:24475108
  66. 66. Lomuscio A, Belletti S, Battezzati PM, Lombardi F. Efficacy of acupuncture in preventing atrial fibrillation recurrences after electrical cardioversion. J Cardiovasc Electrophysiol. 2011;22: 241–247. pmid:20807278
  67. 67. Xu HK, Zhang YF. Comparison between therapeutic effects of acupuncture and intravenous injection of amiodarone in the treatment of paroxymal atrial fibrillation and atrial flutter. Zhongguo Zhen Jiu. 2007;27: 96–98. pmid:17370488
  68. 68. Lee S, Lee MS, Choi JY, Lee SW, Jeong SY, Ernst E. Acupuncture and heart rate variability: a systematic review. Auton Neurosci. 2010;155: 5–13. pmid:20304708
  69. 69. Chung JW, Yan VC, Zhang H. Effect of acupuncture on heart rate variability: a systematic review. Evid Based Complement Alternat Med. 2014;2014: 819–871.