Jh. Cornel et al., Agreement and disagreement between "metabolic viability" and "contractile reserve" in akinetic myocardium, J NUCL CARD, 6(4), 1999, pp. 383-388
Background, In patients with chronic coronary artery disease and depressed
left ventricular function, assessment of residual viability in akinetic myo
cardium is important for therapeutic management. Intact perfusion, preserve
d metabolism, and presence of contractile reserve are different aspects of
cellular viability. However, not all viable cells exhibit all characteristi
cs; it is thought that contractile reserve is less often preserved compared
with metabolic activity or intact perfusion, In this study we performed a
direct comparison between perfusion imaging with thallium-201 single photon
emission computed tomography (SPECT), metabolic imaging with F18-fluorodeo
xyglucose SPECT, and assessment of contractile reserve with low-dose dobuta
mine echocardiography in akinetic myocardium,
Methods and Results, Forty patients with depressed left ventricular functio
n (mean left ventricular ejection fraction 31% +/- 16%) were studied, Resti
ng echocardiography showed akinesis in 165 (32%) segments, Most (n = 154, 9
3%) of these segments demonstrated resting hypoperfusion, F18-fluorodeoxygl
ucose imaging revealed a perfusion-metabolism mismatch in 41 segments and a
match in 113 segments, Contractile reserve was present in 33 (80%) of the
segments with a perfusion-metabolism mismatch and in 7 (6%) segments with a
match (P <.0005). Of the 11 segments with normal perfusion, only 5 (45%) s
howed contractile reserve. The agreement between SPECT and dobutamine echoc
ardiography was 87%, Although 94% of the segments that were nonviable on sc
intigraphy did not show contractile reserve, the disagreement between SPECT
and dobutamine echocardiography was caused mainly by the absence of contra
ctile reserve in 27% of the segments that were viable on scintigraphy,
Conclusion, This study shows a good agreement between SPECT and dobutamine
echocardiography, although a substantial number of segments with preserved
viability on SPECT do not exhibit contractile reserve, indicating underesti
mation of viability by dobutamine echocardiography compared with F18-fluoro
deoxyglucose imaging.