[Acetylsalicylic acid effects on pain sensitivity to myocardial ischemia and skin sensitivity in patients with angina pectoris].

OBJECTIVE

To clarify if pain-relieving action of acetylsalicylic acid (ASA) is associated with lowered sensitivity of anginal patients to pain due to myocardial ischemia.

METHODS

A double blind randomized placebo-controlled trial enrolled 10 males aged 42-69 years with stable effort angina (EA) of functional class II-III. When exposed to exercise tolerance test (treadmill, stress-system Sicard 460S, computed ECG), the patients developed EA attack with at least 1 mm decline of ST segment on ECG. The exercise test was made before, 2 and 4 hours after administration of ASA and placebo. Sensitivity to ischemia was estimated by the total depth of the ST segment decline in 11 ECG leads (sigma ST) registered at the attack onset. Tactile and pain thresholds (TT and PT) were studied with a highly reproducible technique. TT and PT were measured before, 2 and 4 hours after ASA and placebo administration.

RESULTS

2 and 4 hours after intake of 100 mg of ASA, sigma ST and TT significantly rose compared to the baseline level and placebo. PT significantly rose vs the baseline level.

CONCLUSIONS

ASA deteriorates sensitivity of anginal patients to myocardial ischemia, skin tactile and pain sensitivity and thus can deprive the EA patient of the pain attack signal. This leads to the risk of overexercising and emergence of painless myocardial ischemia.