Effect of insulin resistance associated with compensatory hyperinsulinemia on the long-term prognosis in patients with vasospastic angina.

Background: Insulin resistance associated with compensatory hyperinsulinemia plays a significant role in the pathogenesis of cardiovascular diseases, including vasospastic angina (VSA). However, the effects of insulin resistance associated with hyperinsulinemia on the long-term prognosis in patients with VSA remain unclear.

Methods: A total of 265 selected patients with VSA and 56 control subjects with atypical chest pain were enrolled in the present study. Patients with VSA had a positive acetylcholine (ACh) provocation test with normal coronary angiograms, and control subjects had a negative ACh test and normal coronary angiograms. A 75-g oral glucose tolerance test was performed, and the plasma glucose and immunoreactive insulin (IRI) levels were measured before, and 30 min and 120 min (IRI 120) after the 75-g glucose load.

Results: During the median follow-up period of 90.0 months, thirty-one patients developed cardiac events, including 6 sudden cardiac deaths and 25 readmissions for acute coronary syndrome. Cardiac events occurred in 38.9% of the patients with an IRI 120 ≥ 80 μU/ml and only 1.6% of the patients with an IRI 120<80 μU/ml (log rank 77.220, p<0.001). A multivariate analysis showed that an IRI 120 ≥ 80 μU/ml (hazard ratio 27.49, 95% confidence interval: 4.66-162.10, p<0.001) was an independent predictor of cardiac events.

Conclusions: These data indicate that insulin resistance associated with compensatory hyperinsulinemia increases the risk of cardiac events in VSA patients.