Comparison of hemodynamic and stress testing variables in patients undergoing regadenoson stress myocardial perfusion imaging to regadenoson with adjunctive low-level exercise myocardial perfusion imaging

Background: Regadenoson (REG), a selective adenosine A2a receptor agonist, is becoming the preferred pharmacologic agent for stress myocardial perfusion imaging (MPI). Hemodynamic and stress variables, immediate safety and use of aminophylline when using REG combined with low-level exercise (REG WALK MPI) compared with REG MPI, have not been well studied and formed the basis of our study. Methods: Retrospective evaluation of patients who underwent REG MPI (n = 887) was compared to patients undergoing REG WALK MPI (n = 485) from January to November 2009. Patient demographics, hemodynamic parameters, REG MPI data, side effects, immediate major clinical events, and use of aminophylline were evaluated. Results: Patients in REG WALK MPI group tended to be younger, male and obese compared to patients in REG MPI group. REG WALK MPI patients had higher stress heart rate (103 ± 20.5 vs 84 ± 19 bpm, P =.001), higher heart rate reserve (36.3 ± 19 vs 14.7 ± 15.5 bpm, P <.001), and greater systolic blood pressure rise (4.8 ± 21.3 vs -8.9 ± 19.8 mm Hg, P <.001), compared to REG MPI patients. No major adverse events were reported immediately after REG WALK MPI. There were no differences in drug-related side effects in between the two groups; however, the use of aminophylline was lower in REG WALK MPI Group (5.6% vs 11.4%, P =.001). Conclusion: REG WALK MPI gives more favorable hemodynamic response with lesser use of aminophylline and no increase in adverse events when compared with REG MPI.