The aim of this work was to estimate the impact of clinical variables on predicting stress myocardial perfusion abnormalities in patients with suspected coronary artery disease, abnormal resting electrocardiogram, and noninterpretable exercise test.
Material and methods: The clinical variables and stress myocardial perfusion data were analyzed in 370 patients (157 males and 213 females) with suspected coronary artery disease and abnormal resting electrocardiogram. All patients underwent (99m)Tc-methoxyisobutylisonitrile (MIBI) scintigraphy following a one-day protocol (stress-rest). The bicycle exercise test was considered noninterpretable when the age-predicted peak heart rate was not achieved, and ischemic signs were not detected.
Results: One hundred sixty (43.2%) patients had noninterpretable bicycle exercise test. Pathological stress myocardial perfusion defects (reversible and fixed) were more often present in patients with noninterpretable than in patients with informative exercise test (63.1 and 50.0%, respectively, p<0.01). Univariate analysis showed that reversible perfusion defects were more frequent in men than in women (p<0.00001, odds ratio 9.6), in patients with pre-existing left bundle-branch block (p<0.02, odds ratio 3.4), and in cases when sufficient working capacity (> or =150 W) was achieved (p<0.05, odds ratio 2.1).
Conclusion: The myocardial perfusion defects were registered in 63.1% of patients with suspected coronary artery disease, abnormal resting electrocardiogram, and noninterpretable exercise test. The probability of reversible perfusion defects was higher in male patients, in patients with pre-existing left bundle-branch block and with sufficient working capacity (> or =150 W).