How do SMPI studies compare with routine stress ECG studies in the evaluation of patients with CAD?
Generally, a routine stress ECG is sensitive, with positive ECG stress test results indicating a high likelihood for CAD. The accuracy is significantly reduced, however, in patients with abnormal baseline ECGs or a previous history of CAD, or if a patient does not achieve 85% of the maximal heart rate for patient age. In these patients, an SMPI study has a sensitivity of approximately 92% and a specificity of approximately 72% for detecting CAD. The relative prevalence of CAD in the specific patient population is also a factor. Women have a much higher rate of false-positive stress test results because their prestudy risk is much lower than that for men.
