Risk stratification in patients with remote prior myocardial infarction using rest-stress myocardial perfusion SPECT: prognostic value and impact on referral to early catheterization.
BACKGROUND
Little is known about the prognostic value of myocardial perfusion single photon emission computed tomography (SPECT) in patients with remote prior myocardial infarction (MI).


RESULTS
We identified 1413 consecutive patients with remote prior MI who underwent rest-stress myocardial perfusion SPECT. Semiquantitative visual analysis of 20 SPECT segments was used to define the summed stress, rest, and difference scores. The number of non-reversible segments was used as an index of infarct size. During follow-up (>or=1 year), 118 hard events occurred: 64 cardiac deaths (CDs) and 54 recurrent MIs. Annual CD and hard event rates increased significantly as a function of SPECT abnormality. For summed stress scores less than 4, 4 to 8, 9 to 13, and more than 13, the annual CD rates were 0.4%, 0.9%, 1.7%, and 3.5%, respectively (P =.002). Patients with small MI (<4 non-reversible segments) and no or mild ischemia (summed difference score <or=6) had an annual CD rate of 0.6%. Patients with small MI and moderate or severe ischemia had an annual CD rate of 1.6%, and those with large MI (>or=4 non-reversible segments) had moderate to high annual CD rates (3.7%-6.6%) regardless of the extent of ischemia. Nuclear testing added incremental prognostic information to pre-scan information. Compared with a strategy in which all patients are referred to catheterization, a strategy that referred only those patients with a risk for CD of greater than 1% by myocardial perfusion SPECT resulted in a 41.6% cost savings.


CONCLUSIONS
Myocardial perfusion SPECT adds incremental value to pre-scan information and is highly predictive and cost-efficient in the risk stratification of patients with remote prior MI. Patients with normal or mildly abnormal scan results or small MI in combination with absent or mild ischemia have a low risk for CD.
Zellweger
Michael J
MJ
Department of Imaging (Division of Nuclear Medicine), Cedars-Sinai Medical Center, The CSMC Burns and Allen Research Institute, Los Angeles, Calif. 90048, USA.
Dubois
Eric A
EA
Lai
Shenghan
S
Shaw
Leslee J
LJ
Amanullah
Aman M
AM
Lewin
Howard C
HC
Friedman
John D
JD
Kang
Xingping
X
Germano
Guido
G
Berman
Daniel S
DS
D000241:Adenosine; D000368:Aged; D000369:Aged, 80 and over; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D017048:Health Care Costs; D006321:Heart / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000150:complications / Q000000981:diagnostic imaging*; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging* / Q000209:etiology; D017063:Outcome Assessment, Health Care; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon / Q000191:economics / Q000379:methods*
D017256:Technetium Tc 99m Sestamibi; D000241:Adenosine