Exercise Provocation Test in Patients with Vasospastic Angina: Graded vs. Non-Graded Exercise Test

Background and ObjectivesIn patients with coronary vasospastic angina we investigated whether exercise ECG test results vary with the different modes of exercise load and compared various clinical characteristics, including coronary risk factors, between patients with positive and those with negative exercise test results.Materials and MethodsThis study examined 34 patients who had documented coronary artery spasm without significant stenosis (coronary artery luminal diameter narrowing <70%).The two different modes of treadmill exercise ECG tests, the first based on the Bruce's protocol (graded exercise test, GET) and the second on the sudden rapid exercise protocol (non-graded exercise test, NGET), were performed in the morning of the same day.ResultsOf 29 patients who underwent both GET and NGET, 19 patients manifested a positive result by NGET, whereas only 11 did by GET (66 vs. 38%, p0.04).All patients with a positive GET result produced a positive NGET result and 8 of 18 patients with a negative GET result also did.Of 34 patients who underwent GET, there was no significant difference in the frequency of hypertension, diabetes, current smoking, history of effort chest pain, mixed disease (fixed stenosis > 50%, <70% of luminal diameter) or in total cholesterol level between patients with positive and those with negative results.Among 18 patients with typical variant angina by clinical history, 8 of 10 patients with high disease activity (5 or more attacks per week) exhibited a positive result by either GET or NGET, whereas 4 of 8 patients with low disease activity did (80 vs. 50%, pNS).ConclusionIn patients with coronary vasospastic angina, sudden rapid exercise has the potential to induce coronary artery spasm more frequently than multistage exercise.Exercise test results may not be correlated with coronary risk factors, coronary anatomy, effort chest pain, and the disease activity.