Comparison of the prognostic value of normal regadenoson with normal adenosine myocardial perfusion imaging with propensity score matching.
OBJECTIVE
The aim of this study was to test the hypothesis that patients with normal regadenoson myocardial perfusion imaging (MPI) have a low rate of cardiac events, similar to patients with normal adenosine MPI.


BACKGROUND
Regadenoson, a new selective adenosine A(2A) receptor agonist, is now a widely used stress agent for MPI. The low rate of cardiac events in patients with normal adenosine MPI is well-documented, but the prognostic implications of a normal regadenoson MPI have not been examined and compared with those with adenosine.


METHODS
Data on primary composite endpoint (cardiac death, myocardial infarction, and coronary revascularization) were collected for 2,000 patients (1,000 regadenoson, and 1,000 adenosine stress) with normal myocardial perfusion and left ventricular ejection fraction referred for vasodilator MPI. In addition, propensity scores were used to assemble a balanced cohort of 505 pairs of patients who were balanced on 36 baseline characteristics.


RESULTS
The primary endpoint occurred in 21 (2.1%; 1.1%/year) patients in the regadenoson group and 33 (3.3%; 1.7%/year) patients in the adenosine group (hazard ratio [HR] for regadenoson vs. adenosine: 0.62; 95% confidence interval [CI]: 0.36 to 1.08; p = 0.090). In the propensity-matched pairs, the primary endpoint occurred in 7 (1.4%; 0.7%/year) patients in the regadenoson group and 13 (2.6%; 1.3%/year) patients in the adenosine group (matched HR: 0.58; 95% CI: 0.23 to 1.48; p = 0.257). Cardiac deaths were infrequent in the entire sample and in the propensity-matched groups; the cardiac death rate was 0.9%/year and 1.15%/year in the regadenoson and adenosine groups (HR: 0.77; 95% CI: 0.42 to 1.43; p = 0.404) in the pre-match sample and 0.5%/year and 0.7%/year in the matched groups, respectively (HR: 0.83; 95% CI: 0.25 to 2.73; p = 0.763).


CONCLUSIONS
Major cardiac events are infrequent in patients with normal regadenoson MPI. These findings provide assurance that normal MPI using a simpler stress protocol with regadenoson provides prognostic data similar to normal adenosine MPI.
Tulane University Heart and Vascular Institute, New Orleans, LA 70112, USA. fiqbal1@tulane.edu
Fahad M
FM
Iqbal
Fadi G
FG
Hage
Ali
A
Ahmed
Phillip J
PJ
Dean
Saleem
S
Raslan
Jaekyeong
J
Heo
Ami E
AE
Iskandrian
D000241:Adenosine; D058908:Adenosine A2 Receptor Agonists; D000368:Aged; D055426:Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography; D002423:Cause of Death; D016009:Chi-Square Distribution; D005260:Female; D006331:Heart Diseases / Q000000981:diagnostic imaging* / Q000401:mortality / Q000503:physiopathology / Q000628:therapy; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000503:physiopathology; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D009204:Myocardial Revascularization; D011237:Predictive Value of Tests; D011379:Prognosis; D057216:Propensity Score; D016016:Proportional Hazards Models; D011687:Purines; D011720:Pyrazoles; D012016:Reference Values; D012307:Risk Factors; D013318:Stroke Volume; D013997:Time Factors; D014665:Vasodilator Agents; D016277:Ventricular Function, Left
D058908:Adenosine A2 Receptor Agonists; D011687:Purines; D011720:Pyrazoles; D014665:Vasodilator Agents; C430916:regadenoson; D000241:Adenosine