[Role of isotopic techniques in the evaluation of myocardial viability in man].
Modern management of coronary artery disease is increasingly based on techniques of myocardial revascularisation. The introduction of coronary bypass surgery, percutaneous coronary angioplasty and thrombolysis has radically changed the prognosis, reducing the morbidity and mortality related to myocardial infarction and chronic ischaemic heart disease (when associated with left ventricular dysfunction). In this case, the beneficial effects of revascularisation are probably due to improved contractility of dysfunctional tough viable myocardium in response to improved perfusion. Several methods are available for predicting the reversible character of segmental dysfunction after revascularisation. Most are based on fundamental cellular mechanisms thought to contribute to cellular viability and postoperative contractile recovery. These include adequate tissue perfusion for providing energetic substrate and the elimination of metabolic waste; the maintenance of essential membrane functions, the conservation of metabolic pathways for the aerobic use of glucose and fatty acids, and the maintenance of a contractile function capable of ensuring efficacious mechanical activity after surgery. Thallium or MIBI myocardial scintigraphy and position emission tomography (PET) allow the non-invasive evaluation of some of these mechanisms. These techniques are capable of detecting viable myocardium with a high sensitivity (> 80%). They are limited by a lack of specificity (+/- 55% for thallium and +/- 75% for PET). However, all have an additive prognostic value with respect to usual functional (ejection fraction) and anatomical (coronary angiography) parameters.
Vanoverschelde
J L
JL
Service de cardiologie, Université catholique de Louvain. Bruxelles, Belgique.
Pasquet
A
A
Gerber
B
B
Roeland
V
V
Bernard
X
X
Melin
J A
JA
D003326:Coronary Circulation; D005080:Exercise Test; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D009200:Myocardial Contraction; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging*; D009206:Myocardium / Q000378:metabolism*; D012680:Sensitivity and Specificity; D014055:Tomography, Emission-Computed; D015899:Tomography, Emission-Computed, Single-Photon; D016277:Ventricular Function, Left