[Thallium-201 scintigraphy and dobutamine echocardiography in the assessment of myocardial viability].
BACKGROUND
The possibility of differentiating viable from non-viable tissue among patients with severe coronary artery disease and severe left ventricular impairment entails relevant clinical and therapeutic implications since it may influence the indication of patient revascularization. To evaluate the presence of myocardial viability two techniques are available in the clinical setting: echocardiography with intravenous infusion of dobutamine and scintigraphy with myocardial perfusion with thalliem-201 by means of single-photon emission tomography.


OBJECTIVE
To compare prospectively the value of these techniques for detecting viable myocardium.


METHODS
Thirty-five patients with severe coronary disease and severe left ventricular dysfunction were included in the study. All patients underwent an echocardiogram using incremental doses of dobutamine, from 5 up to 40 micrograms/kg/min in three-minute periods. For thallium-201 scintigraphy the rest redistribution protocol with delayed images at 4 hours was used. The criteria for detecting viability were: a) for thallium-201, the presence of redistribution in delayed images and normal uptake at rest, and b) for dobutamine echocardiography, a sustained improvement in regional motion, biphasic response, and worsening.


RESULTS
By considering the segmental improvement post-revascularization as "gold standard" of viability, the statistically significant variables in a logistic regression model and, therefore, predictors of segmental functional recovery were the biphasic response and the sustained response for dobutamine echocardiography and normal uptake at rest and redistribution in the delayed images for thallium-201. Taken together, the result was significant for the biphasic response of dobutamine echocardiography.


CONCLUSIONS
The biphasic response with dobutamine echocardiography is the echocardiographic pattern that best predicts the functional recovery of the ischemic myocardium. A normal uptake and redistribution at four hours is the only scintigraphic pattern that can predict functional improvement. Of both patterns, the biphasic response is the best predictor of the functional recovery of the dysfunctional myocardium.
Peral
V
V
Servicio de Cardiología, Hospital Universitario Son Dureta, C./Andrea Doria, 55, 07014 Palma de Mallorca.
Vilacosta
I
I
de la Peña
A
A
San Román
J A
JA
Fernández
C
C
Hernández
M
M
Batlle
E
E
Carreras
J L
JL
Bethencourt
A
A
D002316:Cardiotonic Agents; D004280:Dobutamine; D004452:Echocardiography; D005080:Exercise Test; D006801:Humans; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000175:diagnosis; D009204:Myocardial Revascularization; D017682:Myocardial Stunning / Q000175:diagnosis*; D011446:Prospective Studies; D013794:Thallium Radioisotopes; D015899:Tomography, Emission-Computed, Single-Photon; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology; D016277:Ventricular Function, Left
D002316:Cardiotonic Agents; D013794:Thallium Radioisotopes; D004280:Dobutamine