Temporal variability and correlation with geometric parameters in vasospastic angina: a quantitative angiographic study.

Abstract

Long-term changes in vasocontractility were examined in 23 coronary segments from 20 patients with variant angina using computer-based quantitative coronary angiography and ergonovine provocation tests repeated at an interval of 42 +/- 14 months. Measurements of vasospasticity at the sites of fixed stenoses were compared with values predicted by an elementary geometric theory based on the assumption that the cross-sectional area of a vessel wall is constant regardless of its state of vasoconstriction. While all patients were symptomatic initially, only 11 remained symptomatic at follow-up. At the initial provocation test, the response was correctly predicted in four segments, was lower than expected in one, and was stronger in 18. At follow-up, only one of the four segments in which the response had been initially predicted correctly again showed the predicted response and the remaining three showed a response weaker than expected; the one segment which was initially hypocontractile remained hypocontractile at follow-up; and of the 18 segments which were initially hypercontractile, 12 exhibited hypercontractility again, four had the predicted value and the remaining two showed hypocontractility. In only one of 23 segments did the geometric theory predict the behaviour of vasospasticity at the site of fixed stenosis on both tests. Vasospastic responsiveness is a dynamic process demonstrating temporal variability and is not directly predicted by geometric theory.