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Prognostic value of weighted quantitative analysis of
coronary artery disease using rest Tl-201 and gated Tc-99m-sestamibi
imaging.
K. A. Thigpen*, M. Ledges, S. M. Munro, A. D. Fisher, N.
Leitman, R. A. Quaife, University of Colorado Health Sciences Center,
Denver, CCO. (500578)
Objectives: The size and severity of stress-induced
myocardial perfusion defects are important determinates of
cardiovascular prognosis. To investigate whether automated
quantification of stress-induced regional perfusion defects could
predict cardiac events, we stdied 126 consecutive patients (followed
for a mean of 15 months), undergoing a dual-isotope gated stress
Tc-99m-sestamibi (gMIBI) perfusion imaging protocol and underwent
coronary angiography, using 4D-MSPECT (University of Michigan)
quantitative analysis software.
Methods: Regional stress perfusion was visually
interpreted using a 20 segment semi-quantitative scoring method by 2
blinded and independent observers. Quantitative stress regional
perfusion (QSP) was automatically determined and weighted to define
severity values for total cardiac and each coronary vascular
distribution stress defect burden. Summed stress scores(SSS) were
calculated from the visual scoring of gMIBI studies. Comparison of
cardiac events was performed using logistic regression analysis for
both visual and quantitative interpretation of stress perfusion
defects.
Results: Hard cardiac events occurred in 10% of patients,
including 8 deaths, 2 myocardial infarctions, and 2 cardiac
transplants. The sensitivity for detecting significant (³50% stenosis)
coronary artery disease was 86% and 84% respectively for both observers
and 86% for the quantitative method. Both SSS and QSP identified
increased cardiac risk of events (X2=7.5 and 9.3 respectively; and p =
.006 and .002 respectively). Additionally, left ventricular ejection
fraction (LVEF) quantitated from g MIBI was lower between those
patients with cardiac events, LVEF = .37 and those patients with out
cardiac events, LVEF = .50; p = .0065).
Conclusions: We conclude that hard cardiac events such as
MI, cardiac transplant, and death are predicted by quantitative
analysis of stress gMIBI studies and is similar to the SSS method. LVEF
determined at the time of gMIBI imaging was significantly reduced and
predictive of cardiac events, but was not independent of the
quantitated stress perfusion values.
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