Abstract 2485: Prognostic Implications of A Normal Real Time Myocardial Perfusion Response in Patients With High Framingham Risk Scores
Background. Clinical trials examining the negative predictive value of various stress tests often include patients who have low pre-test probability of coronary artery disease (CAD). Myocardial perfusion (MP) and wall motion (WM) assessed with real time contrast echocardiography (RTCE) has been utilized to improve the detection of CAD during dobutamine stress echocardiography (DSE). Although MP imaging has improved test sensitivity in this setting, the negative predictive value of a normal WM and MP response in patients considered high risk for CAD has not been evaluated.
Methods. In 372 patients (mean age 64, range 33–92) with Framingham Risk Scores (FRS) greater than 5 in men and 9 in women, the incidence of death or non-fatal myocardial infarction following a normal versus abnormal DSE with RTCE was compared. A study was considered normal if both MP responses (normal replenishment of myocardial contrast following a high mechanical index impulse during a continuous infusion of microbubbles) and wall motion responses to dobutamine were normal at 85% predicted maximum heart rate. Event rates and Kaplan Meier curves were used to compare patients.
Results. Median follow up interval following DSE was 20 months (range 2–36 months). Three year event-free survival in high FRS patients with a normal MP and WM response was 97.5%, compared to 90.6% in patients with abnormal MP responses (Odds ratio 4.05; 95% confidence interval 1.6 –10.6; p = 0.006). Kaplan Meier survival probabilities at 24 months were significantly different (p = 0.0028; Figure⇓)
Conclusions. A normal MP and WM response during DSE has excellent negative predictive value in patients with high Framingham Risk Scores.