Background: Pharmacological stress echocardiography (PSE) is increasingly used for cardiac risk stratification. Our study was undertaken to assess the long-term prognostic significance of PSE in patients with known or suspected coronary artery disease.
Methods: We studied 622 consecutive patients who underwent PSE with either dobutamine or dipyridamole. Outcome was finally assessed in 448 patients for a mean period of 32.9 months. Death and hard events (death and myocardial infarction) were considered as endpoints.
Results: PSE was positive for ischemia in 192 patients (42.9%). During the follow-up, 53 hard events occurred, including 28 deaths and 25 acute non-fatal myocardial infarctions. With multivariate analysis, peak ejection fraction < 40% appeared to be the strongest predictor of cardiac-related deaths and of hard endpoints (chi2 28.4 and 32.0, respectively). Peak wall motion score index revealed a strong predictive value of the same events (chi2 8.6 and 16.3, respectively). An ischemic pattern at PSE predicted a 2.4 higher cardiac mortality rate over a 5-year follow-up (9.4 vs 3.9%, p < 0.01; log rank 5.68), while patients with a peak ejection fraction < 40% had a cardiac-related mortality 4 times higher (16.3 vs 4.1%, p < 0.00001; log rank 21.16). Hard events occurred in 6.7% of patients with a negative test vs 18.8% of patients with a positive test (p < 0.001; log rank 15.8), while hard event rate was 8.4% in patients with a peak ejection fraction > 40% vs 27.5% in patients with a peak ejection fraction < 40% (p < 0.00001; log rank 38.64).
Conclusions: The ischemic response to PSE showed a sustained prognostic value for cardiac events, especially in patients considered at either intermediate or high risk on the basis of recognized clinical risk factors. However, only the evaluation of both descriptors of global left ventricular performance and of the extension of induced ischemia may better help to select patients at higher risk of cardiac death.