Determinants of a positive exercise test in patients admitted with acute non-infarct chest pain

Background and objectives. Some patients with suspected unstable angina show ischemia at the exercise treadmill test despite having been medically stabilized. The objective of this study was to determine clinical characteristics predicting a positive exercise treadmill test in patients with suspected unstable angina after medical stabilization. Methods. In 885 hospitalized patients with medically stabilized unstable angina, the relationship between the result of the pre-discharge exercise treadmill test and clinical characteristics was studied. Results. Mean age was 62±9 years and 668 (75%) were male. Exercise test was positive (chest pain and/or ST depression ≥1 mm) in 288 patients (33%). Univariate analysis showed the following associated with ischemia at the exercise test: male gender (56% vs. 20%, P<0.001), diabetes mellitus (41% vs. 31%, P=0.009), previous unstable angina (41% vs. 24%, P=0.001), previous stable angina (44% vs. 30%, P<0.001), previous coronary artery bypass grafting (43% vs. 31%, P=0.043), peripheral artery disease (45% vs. 31%) and progressive angina (55% vs. 31%, P<0.001). Multivariate analysis showed the following as independent predictors of ischemia: male gender (OR=2.25), diabetes (OR=4.12), previous unstable angina (OR=3.89), previous stable angina (OR=3.74) and progressive angina (OR=4.05). Conclusions. In patients with suspected unstable angina, after medical stabilization: (1) the exercise treadmill test is positive in one-third of cases; (2) male gender, diabetes, previous angina (unstable and stable) and progressive angina are independent predictors of ischemia.