Identification of hibernating myocardium: comparative accuracy of myocardial contrast echocardiography, rest-redistribution thallium-201 tomography and dobutamine echocardiography.
OBJECTIVE
We sought to evaluate the comparative accuracy of myocardial contrast echocardiography (MCE), quantitative rest-redistribution thallium-201 (Tl-201) tomography and low and high dose (up to 40 microg/kg body weight per min) dobutamine echocardiography (DE) in identifying myocardial hibernation.


BACKGROUND
Myocardial contrast echocardiography can assess myocardial perfusion and may therefore be useful in predicting myocardial hibernation. However, its accuracy in comparison to myocardial perfusion scintigraphy and to that of high dose DE remains to be investigated.


METHODS
Eighteen patients (aged [+/- SD] 57 +/- 10 years) with stable coronary artery disease and ventricular dysfunction underwent the above three modalities before coronary revascularization. Myocardial contrast echocardiography was achieved with intracoronary Albunex. Rest echocardiographic and Tl-201 studies were repeated > or = 6 weeks after revascularization.


RESULTS
Of 109 revascularized segments with severe dysfunction, 46 (42%) improved. Left ventricular ejection fraction increased from 38 +/- 14% to 45 +/- 13% at follow-up (p = 0.003). Rest Tl-201 uptake and the ratio of peak contrast intensity of dysfunctional to normal segments with MCE were higher (p < 0.01) in segments that recovered function compared with those that did not. Myocardial contrast echocardiography, thallium scintigraphy and any contractile reserve during DE had a similar sensitivity (89% to 91%) with a lower specificity (43% to 66%) for recovery of function. A biphasic response during DE was the most specific (83%) and the least sensitive (68%) (p < 0.01). The best concordance with MCE was Tl-201 (80%, kappa 0.57). Changes in ejection fraction after revascularization related significantly to the number of viable dysfunctional segments by all modalities (r = 0.54 to 0.65).


CONCLUSIONS
In myocardial hibernation, methods evaluating rest perfusion (MCE, Tl-201) or any contractile reserve have a similar high sensitivity but a low specificity for predicting recovery of function. A limited contractile reserve (biphasic response) increases the specificity of DE. Importantly, the three techniques identified all patients who had significant improvement in global ventricular function.
Nagueh
S F
SF
Department of Medicine, Baylor College of Medicine, The Methodist Hospital, Houston, Texas 77030, USA.
Vaduganathan
P
P
Ali
N
N
Blaustein
A
A
Verani
M S
MS
Winters
W L
WL
Zoghbi
W A
WA
D000368:Aged; D000418:Albumins; D002316:Cardiotonic Agents; D003287:Contrast Media; D004280:Dobutamine; D004452:Echocardiography / Q000379:methods*; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008875:Middle Aged; D009200:Myocardial Contraction; D015428:Myocardial Reperfusion Injury / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D009206:Myocardium / Q000473:pathology*; D011877:Radionuclide Imaging; D012680:Sensitivity and Specificity; D013318:Stroke Volume; D013794:Thallium Radioisotopes; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology
D000418:Albumins; C060687:Albunex; D002316:Cardiotonic Agents; D003287:Contrast Media; D013794:Thallium Radioisotopes; D004280:Dobutamine