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Analgesic effect of acupuncture in patients with stable angina: integrative review

ABSTRACT

BACKGROUND AND OBJECTIVES:

Angina is a clinical syndrome characterized by pain or discomfort, considered stable when it occurs for several weeks without progressing to an acute coronary event. Anginal pain management can be performed with pharmacological and non-pharmacological treatments, among which acupuncture is a non-pharmacological option. The aim of this study was to carry out an integrative review of the analgesic effect of acupuncture in patients with stable angina.

CONTENTS:

An integrative review was carried out in April 2021 in databases: Pubmed, Scopus, Cinahl and Bireme. Controlled descriptors “angina pectoris”, “angina stable”, “acupuncture”, “acupuncture therapy”, “acupuncture analgesia” were used. After screening and analyzing the manuscripts, seven experimental studies of the randomized controlled trial type were selected. The results suggest that acupuncture in patients with stable angina can promote an analgesic effect with clinical improvement of symptoms.

CONCLUSION:

Acupuncture can be an adjuvant therapeutic alternative for the treatment of patients with stable angina, since it can promote an analgesic effect with clinical improvement of symptoms.

Keywords:
Acupuncture analgesia; Acupuncture therapy; Angina pectoris; Angina stable; Pain management

RESUMO

JUSTIFICATIVA E OBJETIVOS:

A angina é uma síndrome clínica caracterizada por dor ou desconforto, considerada estável quando ocorre por várias semanas sem evoluir para um evento coronariano agudo. O manejo da dor anginosa pode ser realizado por meio de tratamentos farmacológicos e não farmacológicos, incluindo a acupuntura como uma opção não farmacológica complementar. O objetivo deste estudo foi realizar uma revisão integrativa sobre o efeito analgésico da acupuntura em pacientes com angina estável.

CONTEÚDO:

Foi realizada uma revisão integrativa no mês de abril de 2021 nas bases de dados: Pubmed, Scopus, Cinahl e Bireme. Foram utilizados os descritores controlados “angina pectoris”, “angina stable”, “acupuncture”, “acupuncture therapy”, “acupuncture analgesia”. Após triagem e análise dos manuscritos, foram selecionados sete estudos experimentais do tipo ensaio controlado randomizado. Os resultados sugerem que a acupuntura pode promover efeito analgésico com melhora clínica dos sintomas em pacientes com angina estável.

CONCLUSÃO:

A acupuntura pode ser uma alternativa terapêutica complementar para tratamento de pacientes com angina estável, uma vez que pode promover efeito analgésico com melhora clínica dos sintomas.

Descritores:
Analgesia por acupuntura; Angina estável; Angina pectoris; Manejo da dor; Terapia por acupuntura

INTRODUCTION

Angina is a clinical syndrome that features pain or discomfort in any of the following areas: chest, epigastrium, jaw, shoulder, back, or upper limbs. It is typically triggered or aggravated by physical activity or emotional stress and mitigated using nitroglycerin and its derivatives. Angina usually affects people with coronary artery disease (CAD), but it can also occur in cases of valvular heart disease, hypertrophic cardiomyopathy, uncontrolled hypertension, and in patients with spasm and coronary endothelial dysfunction11 Cesar LA, Ferreira JF, Armaganijan D, Gowdak LH, Mansur AP, Bodanese LC, et al. Diretriz de doença coronária estável. ABC Cardiol. 2014;103(2):1-59..

An anginal condition is considered stable if it occurs for several weeks and doesn’t develop into an acute coronary event. Seizures typically appear in conditions in which there is increased myocardial oxygen demand in a patient with more than 70% light obstruction of one or more coronary arteries. Additionally, the extension, quantity, location and morphology of the stenoses, the presence of collateral circulation and the vasomotor reactivity of the coronary bed are related to the resulting degree of ischemia22 Abreu LM, Cunha AB. Angina estável sem infarto prévio - artigo de revisão. Rev SOCERJ. 1999;7(4):23-9..

Pharmacological and non-pharmacological treatments are used for relief of anginal pain. Pharmacological treatments include nitrates, calcium channel antagonists, and trimetazidine, which reduce symptoms and episodes of myocardial ischemia11 Cesar LA, Ferreira JF, Armaganijan D, Gowdak LH, Mansur AP, Bodanese LC, et al. Diretriz de doença coronária estável. ABC Cardiol. 2014;103(2):1-59.. Acupuncture is a complementary non-pharmacological therapy option for patients with stable angina33 Xue Y, Zhang X, Yang Q, Zhang Y, Liu Z, Lu W, Huang W. Acupuncture and related therapies for stable angina pectoris: a protocol for network meta-analysis. Medicine. 2020;99(51):e23756.. In China, complementary therapies of Traditional Chinese Medicine (TCM), such as acupuncture, have been used to treat the symptoms of CAD44 Huang X, Guo S, Li F, Tan X, Cai Q, Wang H, Chen P, Wang G, Ma X. Acupuncture as an adjunctive treatment for angina due to coronary artery disease: a meta-analysis. Med Sci Monit. 2019;25:1263-74..

The mechanisms of pain reduction and cardiovascular dysfunction by acupuncture may be related to the release in the central nervous system of excitatory and inhibitory neurotransmitters that alter the processing of sensory information and, ultimately, the autonomic flow and, therefore, cardiovascular function55 Longhurst J. Acupuncture’s cardiovascular actions: a mechanistic perspective. Med Acupunct. 2013;25(2):101-13.. There is a gap in the literature regarding the use of non-pharmacological therapies, especially acupuncture, as adjuvant methods for the relief of pain related to stable angina.

This study’s objective was to perform an integrative review on the analgesic effect of acupuncture in patients with stable angina.

CONTENTS

Integrative review including experimental studies for a better understanding of the subject66 Sousa LMM, Vieira CMAM, Severino SSP, Antunes AV. A metodologia de revisão integrativa da literatura em enfermagem. RIE. 2017;21(2):17-26., carried out with the following steps: formulation of the problem, data collection, data assessment, analysis and interpretation and presentation of results77 Roman AR, Friedlander MR. Revisão integrativa de pesquisa aplicada à enfermagem. Cogitare Enferm. 1998;3(2):109-12..

The study was guided by the following question: is acupuncture an effective complementary non-pharmacological method for the relief of pain related to stable angina?

Searches were performed in the following databases: Pubmed, Scopus, Cinahl, and Bireme, using the controlled descriptors “angina pectoris”, “angina stable”, “acupuncture”, “acupuncture therapy”, “acupuncture analgesia”, with the addition of the Boolean operators AND and OR, during the month of April 2021. Original primary studies, with no restrictions for language and publication year, that investigated the analgesic effect of acupuncture in patients with stable angina were included. The following were excluded: studies that used animal models, systematic reviews, integrative, narrative, and scoping reviews, editorials, letters to the editor, commentaries, experience reports, research involving pediatric population or with other types of unstable, refractory and variant, or prinzmetal angina, and those which did not have the full text available.

The studies found were screened by reading the titles and abstracts. Then, they were read in their entirety so that the eligibility criteria could be analyzed (Figure 1). The data from the included studies were compiled in an electronic spreadsheet prepared by the authors. The main characteristics of the studies were summarized in a table: authors, study design, level of evidence, sample size, and objectives (Table 1). The articles were classified according to the level of evidence proposed in the Oxford Center for Evidence-Based Medicine (OCEBM) tool, which classifies evidence from level one to five, the first level being the most relevant88 OCEBM Levels of Evidence Working Group et al. The Oxford Levels of Evidence 2: Oxford Centre for Evidence-Based Medicine; 2016.2016..

Table 1
Description of articles included in the study

Figure 1
Flowchart of articles identification and selection

A scarcity of studies on the subject was evidenced, a wide variation in the publication period (1986 to 2019), and a large temporal gap for the development of new research. The studies included in the final analysis had experimental design, but most (6; 85.7%) had a small sample size, which increases the probability of random errors and decreases the statistical power of their inferences. The main results of the articles are described in table 2. Although few studies on the use of acupuncture in patients with stable angina were found, literature shows that the application of acupuncture has shown therapeutic effects in other diseases, such as fibromyalgia, providing pain relief and improved quality of life1717 Branco CA, Fonseca RB, Oliveira TRC, Gomes VL, Fernandes Neto AJ. Acupuntura como tratamento complementar nas disfunções temporomandibulares: revisão da literatura. Rev Odontol UNESP. 2013;34(1):11-6., as well as in patients with temporomandibular dysfunction for the control of facial pain1818 Yu J, Jiang Y, Tu M, Liao B, Fang J. Investigating prescriptions and mechanisms of acupuncture for chronic stable angina pectoris: an association rule mining and network analysis study. Evid Based Complement Alternat Med. 2020;2020..

Table 2
Results of articles included in the study.

Acupuncture provided an analgesic effect, with a decrease in the frequency of angina episodes and reduction of nitroglycerin consumption, evidenced in six of the seven articles included in the study99 Zhao L, Li D, Zheng H, Chang X, Cui J, Wang R, Shi J, Fan H, Li Y, Sun X, Zhang F, Wu X, Liang F. Acupuncture as adjunctive therapy for chronic stable angina: a randomized clinical trial. JAMA Intern Med. 2019;179(10):1388-97.

10 Wang M, Chen H, Lu S, Wang J, Zhang W, Zhu B. Impacts on neutrophil to lymphocyte ratio in patients of chronic stable angina pectoris treated with acupuncture at Neiguan (PC 6). Zhongguo Zhen Jiu. 2015;35(5):417-21.

11 Ballegaard S, Karpatschoff B, Holck JA, Meyer CN, Trojaborg W. Acupuncture in angina pectoris: do psycho-social and neurophysiological factors relate to the effect? Acupunct Electrother Res. 1995;20(2):101-16.

12 Richter A, Herlitz J, Hjalmarson J. Effect of acupuncture in patients with angina pectoris. Eur Heart J. 1991;12(2):175-8.

13 Ballegaard S, Meyer CN, Trojaborg W. Acupuncture in angina pectoris: does acupuncture have a specific effect? J Intern Med. 1991;229(4):357-62.
-1414 Ballegaard S, Pedersen F, Pietersen A, Nissen VH, Olsen NV. Effects of acupuncture in moderate, stable angina pectoris: a controlled study. J Inter Med. 1990;227(1):25-30.. The decrease in anginal episodes was strongly evidenced in the largest multicenter clinical trial investigating the adjuvant effects of acupuncture in patients with stable angina99 Zhao L, Li D, Zheng H, Chang X, Cui J, Wang R, Shi J, Fan H, Li Y, Sun X, Zhang F, Wu X, Liang F. Acupuncture as adjunctive therapy for chronic stable angina: a randomized clinical trial. JAMA Intern Med. 2019;179(10):1388-97.. Furthermore, other effects of acupuncture corroborate the clinical improvement of symptoms, evidenced by improved exercise tolerance, which is expressed by the difference in pressure rate between rest and maximal exercise (dPRP) and increased cardiac work capacity1111 Ballegaard S, Karpatschoff B, Holck JA, Meyer CN, Trojaborg W. Acupuncture in angina pectoris: do psycho-social and neurophysiological factors relate to the effect? Acupunct Electrother Res. 1995;20(2):101-16.

12 Richter A, Herlitz J, Hjalmarson J. Effect of acupuncture in patients with angina pectoris. Eur Heart J. 1991;12(2):175-8.

13 Ballegaard S, Meyer CN, Trojaborg W. Acupuncture in angina pectoris: does acupuncture have a specific effect? J Intern Med. 1991;229(4):357-62.

14 Ballegaard S, Pedersen F, Pietersen A, Nissen VH, Olsen NV. Effects of acupuncture in moderate, stable angina pectoris: a controlled study. J Inter Med. 1990;227(1):25-30.
-1515 Ballegaard S, Jensen G, Pedersen F, Nissen VH. Acupuncture in severe, stable angina pectoris: a randomized trial. Acta Med Scand. 1986;220(4):307-13.. This increase in exercise endurance consequently delays the onset of anginal pain1212 Richter A, Herlitz J, Hjalmarson J. Effect of acupuncture in patients with angina pectoris. Eur Heart J. 1991;12(2):175-8..

Additionally, in one study, electrocardiographic analysis revealed decreased ST-segment depression, which is usually increased in angina attacks1212 Richter A, Herlitz J, Hjalmarson J. Effect of acupuncture in patients with angina pectoris. Eur Heart J. 1991;12(2):175-8.. The belief is that the vasodilation resulting from sympathetic inhibition promoted by acupuncture is responsible for the clinical improvement in patients with stable angina1313 Ballegaard S, Meyer CN, Trojaborg W. Acupuncture in angina pectoris: does acupuncture have a specific effect? J Intern Med. 1991;229(4):357-62.. The time and severity of the disease seem to modify the effect of acupuncture in patients with stable angina, since the benefit was greater in mild cases and those with less time of disease1313 Ballegaard S, Meyer CN, Trojaborg W. Acupuncture in angina pectoris: does acupuncture have a specific effect? J Intern Med. 1991;229(4):357-62.. Improvements in well-being, anxiety and depression were other secondary outcomes reported99 Zhao L, Li D, Zheng H, Chang X, Cui J, Wang R, Shi J, Fan H, Li Y, Sun X, Zhang F, Wu X, Liang F. Acupuncture as adjunctive therapy for chronic stable angina: a randomized clinical trial. JAMA Intern Med. 2019;179(10):1388-97.,1414 Ballegaard S, Pedersen F, Pietersen A, Nissen VH, Olsen NV. Effects of acupuncture in moderate, stable angina pectoris: a controlled study. J Inter Med. 1990;227(1):25-30..

As for the studies’ methodology, there was homogeneity among some of the inclusion and exclusion criteria of the studied populations. The diagnosis of stable angina and anginal manifestation in the last six months were pre-requisites for eligibility in the studies. Among the exclusion criteria, previous cardiac surgery, previous acute myocardial infarction (AMI), valvular heart disease, severe heart failure, severe arrhythmias, hypertension, previous treatment with acupuncture, and chest pain of non-cardiac origin were some of the criteria established so that there would be no influence or compromise of the results. Only one of the studies did not consider as an exclusion factor the history of AMI and previous coronary artery bypass graft surgery1212 Richter A, Herlitz J, Hjalmarson J. Effect of acupuncture in patients with angina pectoris. Eur Heart J. 1991;12(2):175-8..

On the other hand, there was heterogeneity among the acupuncture techniques employed in the studies, with the following points and meridians used: pericardium 6 (Neiguan), heart 5 (Tongli), heart 7 (Shenmen), urinary bladder 14 (Jueyinshu), urinary bladder 15 (Xinshu), urinary bladder 20 (Pishu), stomach 36 (Zusanli), large intestine 4 (Hegu), large intestine 11 (Quchi), and liver 3 (Taichong).

A meta-analysis investigating acupuncture prescription for treatment of chronic stable angina through association rule mining, network analysis, and underlying mechanisms revealed that PC6, LU9, and ST36 were the top three acupuncture points used for treatment, and the top three meridians reported were the pericardium meridian, lung meridian, and heart meridian1818 Yu J, Jiang Y, Tu M, Liao B, Fang J. Investigating prescriptions and mechanisms of acupuncture for chronic stable angina pectoris: an association rule mining and network analysis study. Evid Based Complement Alternat Med. 2020;2020.. The present review has the limitation of not including searches on eastern databases and the gray literature. However, the main international databases were included without language and time restrictions. Therefore, taking into account the present findings, it is suggested that acupuncture may be a complementary therapeutic alternative for pain management of patients with stable angina. Nonetheless, additional clinical trials with greater methodological rigor are needed to provide more solid evidence for its implementation in clinical practice, since there is significant heterogeneity between the intervention protocols of the published studies.

CONCLUSION

Acupuncture can promote analgesic effects with clinical improvement of symptoms in patients with stable angina, resulting in the main outcomes: reduced anginal attack rate, decreased nitroglycerin consumption, improved tolerance to exercise, increased cardiac work capacity, decreased ST-segment depression, and improvements in general well-being.

REFERENCES

  • 1
    Cesar LA, Ferreira JF, Armaganijan D, Gowdak LH, Mansur AP, Bodanese LC, et al. Diretriz de doença coronária estável. ABC Cardiol. 2014;103(2):1-59.
  • 2
    Abreu LM, Cunha AB. Angina estável sem infarto prévio - artigo de revisão. Rev SOCERJ. 1999;7(4):23-9.
  • 3
    Xue Y, Zhang X, Yang Q, Zhang Y, Liu Z, Lu W, Huang W. Acupuncture and related therapies for stable angina pectoris: a protocol for network meta-analysis. Medicine. 2020;99(51):e23756.
  • 4
    Huang X, Guo S, Li F, Tan X, Cai Q, Wang H, Chen P, Wang G, Ma X. Acupuncture as an adjunctive treatment for angina due to coronary artery disease: a meta-analysis. Med Sci Monit. 2019;25:1263-74.
  • 5
    Longhurst J. Acupuncture’s cardiovascular actions: a mechanistic perspective. Med Acupunct. 2013;25(2):101-13.
  • 6
    Sousa LMM, Vieira CMAM, Severino SSP, Antunes AV. A metodologia de revisão integrativa da literatura em enfermagem. RIE. 2017;21(2):17-26.
  • 7
    Roman AR, Friedlander MR. Revisão integrativa de pesquisa aplicada à enfermagem. Cogitare Enferm. 1998;3(2):109-12.
  • 8
    OCEBM Levels of Evidence Working Group et al. The Oxford Levels of Evidence 2: Oxford Centre for Evidence-Based Medicine; 2016.2016.
  • 9
    Zhao L, Li D, Zheng H, Chang X, Cui J, Wang R, Shi J, Fan H, Li Y, Sun X, Zhang F, Wu X, Liang F. Acupuncture as adjunctive therapy for chronic stable angina: a randomized clinical trial. JAMA Intern Med. 2019;179(10):1388-97.
  • 10
    Wang M, Chen H, Lu S, Wang J, Zhang W, Zhu B. Impacts on neutrophil to lymphocyte ratio in patients of chronic stable angina pectoris treated with acupuncture at Neiguan (PC 6). Zhongguo Zhen Jiu. 2015;35(5):417-21.
  • 11
    Ballegaard S, Karpatschoff B, Holck JA, Meyer CN, Trojaborg W. Acupuncture in angina pectoris: do psycho-social and neurophysiological factors relate to the effect? Acupunct Electrother Res. 1995;20(2):101-16.
  • 12
    Richter A, Herlitz J, Hjalmarson J. Effect of acupuncture in patients with angina pectoris. Eur Heart J. 1991;12(2):175-8.
  • 13
    Ballegaard S, Meyer CN, Trojaborg W. Acupuncture in angina pectoris: does acupuncture have a specific effect? J Intern Med. 1991;229(4):357-62.
  • 14
    Ballegaard S, Pedersen F, Pietersen A, Nissen VH, Olsen NV. Effects of acupuncture in moderate, stable angina pectoris: a controlled study. J Inter Med. 1990;227(1):25-30.
  • 15
    Ballegaard S, Jensen G, Pedersen F, Nissen VH. Acupuncture in severe, stable angina pectoris: a randomized trial. Acta Med Scand. 1986;220(4):307-13.
  • 16
    Pereira HS, Nunes MS, Ribeiro CJ, Ribeiro MC. Efeitos da acupuntura na fibromialgia: revisão integrativa. BrJP. 2021;4(1):68-71.
  • 17
    Branco CA, Fonseca RB, Oliveira TRC, Gomes VL, Fernandes Neto AJ. Acupuntura como tratamento complementar nas disfunções temporomandibulares: revisão da literatura. Rev Odontol UNESP. 2013;34(1):11-6.
  • 18
    Yu J, Jiang Y, Tu M, Liao B, Fang J. Investigating prescriptions and mechanisms of acupuncture for chronic stable angina pectoris: an association rule mining and network analysis study. Evid Based Complement Alternat Med. 2020;2020.

Publication Dates

  • Publication in this collection
    16 Feb 2022
  • Date of issue
    Jan-Mar 2022

History

  • Received
    02 July 2021
  • Accepted
    17 Dec 2021
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