A meta-analysis of eight clinical trials conducted between 2000 and 2014 demonstrates the efficacy of acupuncture for the treatment of stable angina. (1) In all eight clinical trials, patients treated with acupuncture experienced a greater rate of angina relief than those in the control group treated with conventional drug therapies (90.1% vs 75.7%). (2) Additionally, the ECG (electrocardiogram, EKG) results of seven studies demonstrate the superiority of acupuncture over conventional drug therapies for the improvement of ST segment (flat portion of the ECG wave between S and T) ischemia. (3)
Angina pectoris is a symptom of transient myocardial ischemia and hypoxia. (4) It is characterized by temporary pain and a feeling of constriction in the chest, as well as substernal pain that may radiate to the neck, jaw, shoulder, back, arm and epigastrium. (5) The most common risk factor for angina pectoris is coronary artery disease (CAD). (6) Patients with angina are at increased risk for acute myocardial infarction; the prognosis depends on the severity of the CAD and the degree to which their heart function is impaired. Though incidence of angina pectoris differs between countries, it is estimated that between 4.9 – 12.5% of men and 5 – 9.2% of women will experience it each year. (7)
In Traditional Chinese Medicine (TCM), angina pectoris is known as Zhen Xin Tong (true chest pain). According to pattern differentiation, there are three basic patterns that lead to angina pectoris: deficiency of heart qi or yang, heart blood stasis, and phlegm-damp retention. Deficiency of heart qi or yang is a constitutional weakness of the heart, which impairs its function. Over a long time, heart qi deficiency can produce qi stagnation and blood stasis. Phlegm-damp accumulation can also cause qi stagnation and subsequent blood stasis.
Stabbing pain is a key sign for diagnosing blood stasis, and is a defining characteristic of angina pectoris, but constitutionally this may be caused by deficiency (heart qi or yang deficiency) or excess (phlegm-damp accumulation). The authors do not provide any information regarding pattern differentiation, but they do note that, “patients with acupuncture of supplementing and activating Zongqi [pectoral qi] could effectively treat stable and exertional angina pectoris.” (8)
The researchers analyzed only randomized-controlled trials (RCTs) of patients that met the criteria for angina pectoris as formulated by the WHO (World Health Organization). The patients included in the eight studies had been diagnosed with stable angina pectoris for at least three months; acupuncture treatment in all trials lasted at least one week and the observation period was at least 10 days. Across the eight trials there were 640 patients with angina pectoris (mean age 45), 372 of whom received acupuncture treatment as a part of the experimental group.
Some studies included additional TCM therapies such as cupping, moxibustion and ear acupressure. The control groups were all treated with common drug therapies, including: Shanhai Dan capsule, compound Tanshen tablets, isosorbide dinitrate, metoprolol and aspirin. (9) One study also compared the time to the onset of angina relief; the results show that nitrates provide more immediate relief than acupuncture. (10)
Current drug treatments (nitrates, beta blockers, calcium antagonists, aspirin and ACE inhibitors) improve the prognosis of patients with angina pectoris, but may be accompanied by undesirable side effects. Nitroglycerin is the standard for immediate symptom relief, but there is a risk of tolerance and rebound. (11) Nitrates vasodilate and decrease left ventricular volume but may increase oxygen supply by selectively redistributing the flow to ischemic areas. (12) Propranolol, a beta-blocker, decreases both heart rate and contractility but increases left ventricular volume. (13) While patients in a more critical position may require drugs such as these to prevent acute myocardial infarction, the adverse effects limit their utility amongst patients with stable angina pectoris, making the development of new treatment protocols imperative. (14)
Acupuncture is the stimulation of acupuncture points with fine filiform needles. In assessing the efficacy and safety of acupuncture for angina pectoris, the results show “that patients with acupuncture therapy significantly increased the clinical curative effects of angina relief, improved the electrocardiography, and reduced the nitroglycerin consumption than that with conventional drugs. No acupuncture related adverse effect was found.” (15) Furthermore, acupuncture combined with conventional drugs (ACCD) considerably decreased “the frequency and the required dosage of drug taking, thereby decreasing the unpleasant side effects of drug therapy,” (16) as well as making acupuncture “cost beneficial in patients with advanced angina pectoris.” (17)
Acupuncture was used in all eight of the studies; one used electroacupuncture by gently stimulating the acupuncture points with an electrical current connected to the acupuncture needles. Two of the studies also stimulated the acupuncture points with moxibustion, which is the burning of moxa (mugwort) on or near the needles to increase warmth at the area of insertion, and promote movement of qi in the channel that is stimulated. Two used cupping, which is the use of suction cups to stimulate points or meridians. One study used ear acupressure in addition to acupuncture; the ears have acupuncture points that can be stimulated with small blunt tools such as probes or ear seeds in lieu of needles.
The point selection provided encompasses all patients across the eight different studies. For constitutional deficiency, the following acupoints were employed:
- BL15 (Xinshu)
- BL17 (Geshu)
- BL18 (Ganshu)
- BL20 (Pishu)
- BL23 (Shenshu)
- HT7 (Shenmen)
- PC7 (Daling)
- ST36 (Zusanli)
- CV6 (Qihai)
For moving stasis, the following acupoints were used:
- HT5 (Tongli)
- PC3 (Quze)
- PC4 (Ximen)
- PC5 (Jianshi)
- PC6 (Neiguan)
- CV17 (Danzhong)
Overall, the results clearly show the potential of acupuncture for the treatment of stable angina pectoris. They show that, “ACCD is safe and effective for intractable angina pectoris and it can improve short term prognosis.” (18) While drug therapies are still indicated for their speed in treating acute attacks, acupuncture can help increase overall well-being if administered judiciously. Although further clinical trials are needed, there is a clear indication that “acupuncture therapy may be effective and safe for treating stable angina pectoris,” (19) and that it is a highly effective and cost effective adjunct therapy.
Notes
(1) Zhang Z, Chen M, Zhang L, Zhang Z, Wu W, Liu J, Yan J, and Yang G. Meta-Analysis of Acupuncture for the Treatment of Stable Angina Pectoris. International Journal of Clinical and Experimental Medicine (2015) Vol 8, no. 4 (2015): 5112-5120.
(2 – 3) Zhang, et al. Meta-Analysis of Acupuncture for the Treatment of Stable Angina Pectoris. 5115.
(4) Wang J, Liao E, Huang C and Qi H. Internal medicine (for 8-year and 7-year clinical and other professional). Beijing: People’s Medical Publishing House; 2010. Vol 283. pp. 292.
(5) Gibbons RJ, Abrams J, Chatterjee K, Daley J, Deedwania PC, Douglas JS, Ferguson TB, Fihn SD, Fraker TD and Gardin JM. ACC/AHA 2002 guideline update for the management of patients with chronic stable angina-summary article a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on the Management of Patients With Chronic Stable Angina). J Am Coll Cardiol 2003; 41: 159-168.
(6) Lo MY, Bonthala N, Holper EM, Banks K, Murphy SA, McGuire DK, de Lemos JA, Khera A. A risk score for predicting coronary artery disease in women with angina pectoris and abnormal stress test finding. Am J Cardiology. 2013;111:781–785.
(7) Skalidis EI, Vardas PE. Guidelines on the management of stable angina pectoris. Eur Heart J. 2006;27:2606–2606.
(8) Zhang, et al. Meta-Analysis of Acupuncture for the Treatment of Stable Angina Pectoris. 5118.
(9) Zhang, et al. Meta-Analysis of Acupuncture for the Treatment of Stable Angina Pectoris. 5114-5115.
(10) Zhang, et al. Meta-Analysis of Acupuncture for the Treatment of Stable Angina Pectoris. 5116.
(11) Parker JD, Parker JO. Nitrate Therapy for Stable Angina Pectoris. Survey of Anesthesiology. 1999;43:6.
(12) Heidenreich PA, McDonald KM, Hastie T, Fadel B, Hagan V, Lee BK, Hlatky MA. Meta-analysis of trials comparing β-blockers, calcium antagonists, and nitrates for stable angina. JAMA. 1999;281:1927–1936.
(13) Leon MB, Rosing DR, Bonow RO, Lipson LC, Epstein SE. Clinical efficacy of verapamil alone and combined with propranolol in treating patients with chronic stable angina pectoris. Am J Cardiol. 1981;48:131–139.
(14 – 15) Zhang, et al. Meta-Analysis of Acupuncture for the Treatment of Stable Angina Pectoris. 5117.
(16 – 19) Zhang, et al. Meta-Analysis of Acupuncture for the Treatment of Stable Angina Pectoris. 5118.
