Predictors of inexplicable coronary artery spasm during coronary angiography in patients with stable angina--the role of intravascular oxidative stress.

OBJECTIVE

This study was conducted to investigate the potential role of intravascular oxidative stress in inexplicable episodes of coronary artery spasm (CAS) during coronary angiography (CAG).

METHODS

Serial patients with stable angina scheduled for routine CAG were prospectively evaluated. Patients with clinical evidence of variant angina were excluded. Blood sampling was done immediately before CAG.

RESULTS

Inexplicable episodes of CAS were identified during CAG in 7 patients with and 8 patients without significant coronary artery disease (CAD). Compared to those without CAS (n=220), the 15 patients with CAS had significantly increased plasma triglyceride level, white blood cell (WBC) count and superoxide production in whole blood, and reduced plasma high-density lipoprotein (HDL) level. In multivariate analysis, CAS episodes were associated with an elevated baseline WBC count (relative risk, RR, of increasing one tertile, 2.49) and peak whole blood superoxide production (RR, 2.36), and a reduced plasma HDL level (RR, 0.37).

CONCLUSIONS

Both an increased WBC count and superoxide production in whole blood preceded and predicted the inexplicable development of CAS during CAG irrespective of the presence of CAD, suggesting that intravascular oxidative stress might be the major mediator. Antioxidants given before CAG may be warranted to prevent CAS episodes.