Abstract 6131: Regadenoson Induces Perfusion Defects of Comparable Extent and Severity as Adenosine: A Quantitative Analysis from the ADVANCE 2 Trial
The quantified total and ischemic left ventricular (LV) perfusion defect size (PDS) is an important determinant of subsequent patient outcome. Therefore it is important to determine whether a new stressor agent induces similar perfusion abnormalities as a standard stressor agent such as adenosine. The ADVANCE 2 was a double-blind randomized trial comparing image results in patients undergoing standard adenosine (Ad) SPECT who were then randomized to either a second Ad SPECT (N=260) or SPECT following pharmacologic stress with Regadenoson (Reg) (N=493). All raw data of gated SPECT images (2 sets/patient) were reconstructed and reoriented in a standard fashion. Quantitative SPECT was performed using a previously validated automated program which determined the extent and severity of left ventricular (LV) perfusion defect size (PDS) and the extent of scintigraphic ischemia. PDS severity was defined as mild, moderate or severe based on the relation to normal pixel count activity (>50%, 26–50%, and 0–25%, respectively). Quantification was performed blinded to randomization and image sequence. Baseline perfusion results were similar (p>.05) between patients randomized to Ad vs Reg with respect to total (10.2±14.8 vs 11.5±15.8), ischemic (4.2±7.8 vs 4.6±8.9) and scar (6.0±10.7 vs 6.9±11.3) LV PDS. Results are summarized in the table⇓ below. Linear regression analysis showed a close correlation between Ad vs Reg for total (r=0.97, p<.0001) and ischemic (0.94, p<.0001) LV PDS. In this large database, quantitative SPECT analysis demonstrates that Regadenoson induces a comparable extent and severity of perfusion abnormality as induced with standard adenosine stress. This implies that similar prognostic information should be obtainable with Regadenoson stress as observed with adenosine.