Abstract 20926: Combined Regadenoson with Symptom Limited Exercise for Myocardial Perfusion Imaging; Initial Experience and Comparison with Low-level Exercise and No-Exercise Regadenoson testing
Background: Vasodilator stress with dipyridamole or adenosine is often combined with low-level exercise (ex) and sometimes with higher levels (symptom-limited) ex. Symptom-limited ex combined with regadenoson (Reg) may be beneficial, but there are no published data describing this practice. Because clinically significant changes in systolic BP have been described after Reg in some patients (pts), it is important to know if this effect is more common when Reg is combined with ex.
Methods: To evaluate the safety of combined symptom-limited ex and peak ex injection of Reg, we studied 164 pts who had this performed in conjunction with myocardial perfusion imaging. Pts were referred for either pharmacological testing and underwent the combined ex-vasodilator stress test per clinical protocol, or were tested initially with ex and were given Reg near peak ex after being unable to achieve adequate HR response. The BP changes at time of Reg injection for these pts (Grp 1) were compared to the BP changes of 34 pts who were tested with Reg combined with low level ex (1.7 mph, 0% grade) (Grp 2) and with 68 pts who underwent Reg stress testing with no ex (Grp 3).
Results: Grp 1 had 109 (66.5%) males, mean age 57 ± 11y, mean BMI 30± 6, 67 (40.9%) with known CAD). Mean level of ex was 7.7 ± 2.7 mets, mean peak treadmill speed 2.7 ± 0.8 mph, and mean peak incline 10.6 ± 4.9 % grade. The mean HR at the time of Reg injection was 112.0 ± 17.2 bpm. Mean increase in HR after Reg injection was 8.2 ± 16.0 bpm. No pts developed heart block or were hospitalized, 23 (14.0%) pts were monitored beyond the standard 6 min of recovery. Aminophylline was given in 1 (0.7 %). Systolic BP response is shown in the table:
Conclusions: Symptom-limited ex combined with Reg vasodilator stress appears to be generally well tolerated. However, 32% of pts had a marked > 40 mmHg increase or ≥ 30 mm/hg decrease in SBP, not observed in any pts tested at rest or low level ex with Reg. Larger studies are warranted to identify pts in whom this protocol may not be advised.
- © 2010 by American Heart Association, Inc.