[Correlation Between Referred Pain Region and Sensitized Acupoints in Patients with Stable Angina Pectoris and...

To observe the correlation between the referred pain regions of stable angina pectoris (SAP) and the acupoints in coronary heart disease (CHD) patients and to investigate the rule of regional sensitized point distribution in rats.

A total of 1 046 CHD patients with SAP from 8 hospitals in China were recruited in the present study. The tenderness was palpated along the left and right chest, back, shoulder, upper limb, etc. by a specially-assigned researcher in each hospital. Among them, 77 patients accepted pain threshold (PT) measurement by using a hand-held esthesiometer. In animal experiments, 14 SD rats were subjected to occlusion of the left anterior descending branch of the left coronary artery for 4 h for establishing myocardial ischemia (MI) model, and other 4 normal rats were used as the sham-operation control group. Four hours after MI, all the rats accepted tail venous injection of 5% Evans blue (50 mg/kg) for examining the distribution of the blue dye exudation spots at the body surface where the mechanical PT was also detected by a von Frey.

In 1 046 CHD patients, 987 (94.36%) were found to have at least one tenderness spot. The tenderness spots were found at the left chest (87.47%), right chest (13.67%), left arm (ulnar side, 41.30%), right upper limb (4.68%), left shoulder back (30.21%), right shoulder back (7.07%), etc., accompanied with rash or pigmentation, subcutaneous induration, cord-like tissue contracture, skin sag, etc. The mechanical PT level was significantly lower at the tenderness spots of the left upper limb than at non-tender points of the right upper limb in CHD patients (P<0.001). Tenderness and cutaneous abnormal changes in angor pectoris patients distributed mostly on the left chest, back, shoulder and upper limb, and some also on the right. Tender points scattered on, near or outside acupoints. A similar distribution of the blue exudation spots and lower mechanical PT spots were found in MI rats, but not in sham-MI rats.

In the case of MI, a regular "referred sensitization" response frequently occurs in the dermatomere area innervated by the corresponding segments (T 1－T 5) in both CHD patients and MI rats, which may be closely associated with the formation of acupoints in ancient China.