Purpose: Stress echocardiography (SE) and radionuclide perfusion imaging are competing diagnostic methods in patients with ischemic heart disease. The prognostic value of nuclear studies has been much better established so far. The purpose of the study was to evaluate the long term prognostic value of pharmacological stress echocardiography.
Methods: We followed up 224 patients (62% men, aged 55 +/- 10 yrs) diagnosed with pharmacological stress echocardiography with ischemic heart disease, 46% with angina, 39% with hypertension, 43% with hypercholesterolemia, 12% current smokers, 44% previous smokers, 10% with diabetes mellitus. Positive SE result was defined as new or increased wall motion abnormalities. Follow-up period ranged from 12 to 91 months, average 53 +/- 19 months. Myocardial infarction, recurrent unstable angina requiring hospitalization and need for invasive surgical revascularization or death were defined as adverse outcome.
Results: Positive SE result was observed in 109 patients (48%). During follow-up, 21 patients died (9%) and in 132 patients (59%) other cardiac events were observed. Positive predictive value (PPV) during follow-up was 51% (for cardiac death--8%) for the first year and 7-12% (for cardiac death--0-4%) in the years 2-5. 51% for first year and 7-12% for 2-4 year. Negative predictive value (NPV) was 82% for the first year (for cardiac death--98%) and 79-94% (for cardiac death--99-100%) in years 2-5. 82% for first year and 94-92% in further follow-up. However, 1-year PPV for mortality was 8% with a high NPV (98%). 5-year death-related NPV of the test is very high (100%).
Conclusion: Negative result of SE has a moderate NPV for 1 year cardiac event but high NPV for mortality. NPV in 2-5 years of follow-up in patients with negative SE results is high. PPV is higher in the first 1 year than in further follow-up which results partly from selection bias and remains stable thought area 5 years.