A multinational study to establish the value of early adenosine technetium-99m sestamibi myocardial perfusion imaging in identifying a low-risk group for early hospital discharge after acute myocardial infarction.
OBJECTIVE
The purpose of this study was to determine whether gated adenosine Tc-99m sestamibi single-photon emission computed tomography (ADSPECT) could accurately define risk and thereby guide therapeutic decision making in stable survivors of acute myocardial infarction (AMI).


BACKGROUND
Controversy continues as to the role of noninvasive stress imaging in stratifying risk early after AMI.


METHODS
The INSPIRE (Adenosine Sestamibi Post-Infarction Evaluation) trial is a prospective multicenter trial which enrolled 728 clinically stable survivors of AMI who had gated ADSPECT within 10 days of hospital admission and subsequent 1-year follow-up. Event rates were assessed within prospectively defined INSPIRE risk groups based on the adenosine-induced left ventricular perfusion defect size, extent of ischemia, and ejection fraction.


RESULTS
Total cardiac events/death and reinfarction significantly increased within each INSPIRE risk group from low (5.4%, 1.8%), to intermediate (14%, 9.2%), to high (18.6%, 11.6%) (p < 0.01). Event rates at 1 year were lowest in patients with the smallest perfusion defects but progressively increased when defect size exceeded 20% (p < 0.0001). The perfusion results significantly improved risk stratification beyond that provided by clinical and ejection fraction variables. The low-risk INSPIRE group, comprising one-third of all enrolled patients, had a shorter hospital stay with lower associated costs compared with the higher-risk groups (p < 0.001).


CONCLUSIONS
Gated ADSPECT performed early after AMI can accurately identify a sizeable low-risk group who have a <2% death and reinfarction rate at 1 year. Identifying these low-risk patients for early hospital discharge may improve utilization of health care resources at considerable cost savings.
Mahmarian
John J
JJ
Methodist DeBakey Heart Center, Department of Cardiology, The Methodist Hospital, Houston, Texas 77030, USA. jmahmarian@tmh.tmc.edu
Shaw
Leslee J
LJ
Filipchuk
Neil G
NG
Dakik
Habib A
HA
Iskander
Sherif S
SS
Ruddy
Terrence D
TD
Henzlova
Milena J
MJ
Keng
Felix
F
Allam
Adel
A
Moyé
Lemuel A
LA
Pratt
Craig M
CM
D000241:Adenosine; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging*; D010351:Patient Discharge; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D018570:Risk Assessment; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon
D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi; D000241:Adenosine