OBJECTIVE:
To assess the effectiveness and safety of acupuncture therapy for angina pectoris.

METHODS:
Randomized controlled trials (RCTs) concerned with acupuncture treatment of angina pectoris were identified by searching Academic Source Premier, MEDLINE, Science Citation Index Expanded, and three Chinese databases (China biology medicine database, China national knowledge infrastructure, and VIP database for Chinese technical periodicals). The valid data were extracted in accordance with our inclusion and exclusion criteria. The main outcomes of the included studies were synthesized using Revman 5.1.

RESULTS:
Twenty-one articles on 16 individual studies were included and evaluated as having high or moderate risk of bias according to the standards of the Cochrane Collaboration. Meta-analysis indicated that acupuncture combined with conventional drugs (ACCD) was superior to conventional drugs alone in reducing the incidence of acute myocardial infarction (AMI) [OR = 0.18, 95% CI (0.04, 0.84), P = 0.03]. Moreover, ACCD was superior to conventional drugs in the relief of angina symptoms [OR = 4.23, 95% CI (2.73, 6.56), P < 0.00001], and improvement of electrocardiography (ECG) [OR = 2.61, 95% CI (1.83, 3.73), P < 0.00001]. Acupuncture by itself was also superior to conventional drugs for angina symptoms [OR = 3.59, 95% CI (1.76,7.92), P = 0.0004] and ECG improvement [OR = 3.07, 95% CI (1.54, 6.10), P = 0.001]. ACCD was superior to conventional drugs in shortening the time to onset of angina relief [WMD = -1.40, 95% CI (-1.65, -1.15), P < 0.00001]. However, the time to onset was significantly longer for acupuncture treatment than for conventional treatment alone [WMD = 2.43, 95% CI (1.63, 3.23), P < 0.000 01].

CONCLUSION:
ACCD reduced the occurrence of AMI, and both acupuncture and ACCD relieved angina symptoms and improved ECG. However, compared with conventional treatment, acupuncture showed a longer delay before its onset of action. This indicates that acupuncture is not suitable for emergency treatment of heart attack. Owing to the poor quality of the current evidence, the findings of this systematic review need to be verified by more RCTs to enhance statistical power.