Prognostic value of quantitative stress myocardial perfusion imaging in unstable angina patients with negative cardiac enzymes and no new ischemic ECG changes.
BACKGROUND
Limited data are available on the value of quantitative stress myocardial perfusion imaging (MPI) in patients with unstable angina. In this report we sought to study the long-term prognostic value of quantitative stress MPI in patients hospitalized with unstable angina with no new ischemic electrocardiographic changes and negative cardiac enzymes.


RESULTS
The study population consisted of 136 patients who were hospitalized at the Methodist Hospital, Houston, Tex, with unstable angina and subsequently underwent MPI before discharge. Cox proportional hazards (regression) analysis was performed to identify clinical and MPI predictors of hard cardiac events (death or nonfatal myocardial infarction). During a mean follow-up of 31 +/- 17 months, 20 patients (15%) sustained either cardiac death (n = 12) or nonfatal myocardial infarction (n = 8). The significant multivariate predictors of cardiac events were the total perfusion defect size ( P = .002), the presence of reversible perfusion defects ( P = .01), and the presence of multiple perfusion defects ( P = .03). The perfusion defect size was significantly larger in patients with events than in those without events (21% +/- 20% vs 12% +/- 14%, P = .002). Kaplan-Meier analysis showed that cardiac events were much more likely to develop in patients with defects involving 15% or more of the left ventricle than in those with defects involving less than 15% of the left ventricle ( P = .003).


CONCLUSIONS
In patients hospitalized with unstable angina with no new ischemic electrocardiographic changes and negative cardiac enzymes, quantitative stress MPI provides powerful prognostic information that can be used in the risk stratification of these patients.
Dakik
Habib A
HA
Division of Cardiology, American University of Beirut, Lebanon. hd01@aub.edu.lb
Hwang
Wayne S
WS
Jafar
Aman
A
Kimball
Kay
K
Verani
Mario S
MS
Mahmarian
John J
JJ
D000789:Angina, Unstable / Q000097:blood / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000401:mortality*; D002986:Clinical Trials as Topic; D003402:Creatine Kinase / Q000097:blood; D052279:Creatine Kinase, MB Form; D004562:Electrocardiography; D005080:Exercise Test / Q000706:statistics & numerical data*; D006801:Humans; D007527:Isoenzymes / Q000097:blood; D009203:Myocardial Infarction / Q000097:blood / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000401:mortality*; D010818:Practice Patterns, Physicians'; D011379:Prognosis; D016016:Proportional Hazards Models; D011877:Radionuclide Imaging; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D016019:Survival Analysis; D013781:Texas / Q000453:epidemiology; D020107:Troponin T / Q000097:blood
D007527:Isoenzymes; D020107:Troponin T; D003402:Creatine Kinase; D052279:Creatine Kinase, MB Form