New non-invasive protocol for detection of coronary spastic angina with significant organic stenosis

This study sought to determine whether a newly-combined test, accelerated exercise following mild hyperventilation (HV) is more beneficial to detect ischaemic evidence in patients with pharmacology-induced coronary artery spasm (CAS) and luminal narrowing of > 75% than classic methods.

Forty consecutive patients who all had luminal narrowing of > 75% but < 90% and pharmacology-induced coronary vasospasms of fixed lesions were involved in this study. In these patients, initial HV test, followed by treadmill (TM) exercise test and lastly the newly combined test were performed on three consecutive days. Of the 40 patients, firstly six, secondarily 16 and lastly 32 had positive responses to the HV test, TM exercise test, and newly combined test, respectively. The remaining six patients (15%) had negative results, although the triple sequential tests were performed. Thus, sensitivity of the HV test, the TM exercise test, and the newly combined test was 15% (6/40), 40% (16/40), and 84% (32/38), respectively. Specificity of the three tests were all 100% (46/46). Non-sustained ventricular tachycardia and hypotension were observed in two (5%) patients. However, no serious or irreversible complications were encountered in this study.

We recommend the newly combined protocol rather than the classic tests for the detection of ischaemic evidence in patients with coronary spastic angina and fixed stenosis.