[Myocardial contractility and viability. A radionuclide tomography study using technetium-99m labeled isonitriles].
BACKGROUND
There are comparatively few studies evaluating the patterns of myocardial viability and its relation with contractility in patients with coronary artery disease. The aim of the present study was to quantify the viable and nonviable myocardium, using 99m-technetium isonitriles SPET, as related with left ventricular regional wall motion abnormalities.


METHODS
61 consecutive patients with coronary artery disease were investigated. The severity and extension of the defects were evaluated using a qualitative and quantitative analysis of the 99mTc-isonitriles SPET and compared with ventricular wall motion in contrast ventriculography. An uptake level of 40% of peak uptake or higher was considered as indicating viable myocardium.


RESULTS
Of the 244 evaluated regions (4 per patient), 72 (29%) had normal perfusion, 100 (41%) were ischemic, 25 (10%) had a mild irreversible defect and 47 (19%) had a severe irreversible defect. Wall motion was normal in 176 regions (72%), 29 (12%) were hypokinetic, and 39 (16%) were akinetic of dyskinetic. The amount of viable myocardium in akinetic and dyskinetic regions (64.8%) was significantly different (p < 0.05) from that in hypokinetic (86.1%) and normokinetic (98.8%) regions. Visual assessment of uptake underestimated myocardial viability, as quantitative analysis disclosed that in 61% of akinetic and dyskinetic regions with severe irreversible defects there was more than 50% of viable myocardium.


CONCLUSIONS
In 61% of akinetic and dyskinetic regions with a severe irreversible defect in perfusion scintigraphy positive viability criteria were found. Therefore, visual assessment of the myocardial perfusion studies using 99mTc-MIBI SPET underestimates viable myocardium. Tomographic studies with quantification of the uptake and defect extension are required for a proper evaluation of viable myocardium.
Tamosiunas
G
G
Servico de Cardiología, Hospital General Universitari Vall d'Hebron, Barcelona.
Castell
J
J
Candell Riera
J
J
Fraile
M
M
Aguadé
S
S
García-Burillo
A
A
D000328:Adult; D000368:Aged; D003287:Contrast Media; D017023:Coronary Angiography; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D009203:Myocardial Infarction / Q000000981:diagnostic imaging; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon
D003287:Contrast Media; D017256:Technetium Tc 99m Sestamibi
Contractilidad y viabilidad miocárdicas. Estudio mediante tomogammagrafía con isonitrilos marcados con tecnecio-99m.