Resumo

ARAMAYO GERONIMO, Ema N et al. Relationship between Myocardial Viability, Myocardial Flow and Coronary Anatomy by Positron Emission Tomography Integrated with Multislice Computed Tomography. Rev. argent. cardiol. [online]. 2013, vol.81, n.2, pp.122-128. ISSN 1850-3748.  http://dx.doi.org/10.7775/rac.es.v81.i2.737.

Background The relationship between myocardial viability, myocardial flow and the degree of epicardial coronary stenosis in patients with coronary artery disease and left ventricular dysfunction is unclear. Objective The purpose of this study is to determine whether positron emission tomography (PET) viability and myocardial flow at rest correlate with the degree of epicardial coronary stenosis. Methods Myocardial viability was evaluated in 27 patients by the combined analysis of ¹³N-Ammonia (¹³NH₃) perfusion and ¹⁸F-fluoro-2-deoxyglucose (FDG) metabolism to identify four PET patterns: match (concordant reduced uptake of both radiotracers), mismatch (hypoperfusion with preserved FDG uptake), reverse mismatch (preserved perfusion and reduced FDG uptake) and preserved uptake of both radiotracers. Myocardial blood flow was calculated using a two-compartment model. Coronary artery stenosis was classified as mild (50%), severe (>70%) and critical (= 90%). Results From 459 analyzed segments, 33% were match, 12% mismatch, 11% reverse-mismatch and 44% preserved. Mismatch, reverse-mismatch and preserved patterns exhibited higher flows than the match pattern (p < 0.01). Fifteen coronary lesions were mild, 7 moderate, 20 severe and 39 critical. There was no correlation between the degree of coronary stenosis and viability patterns (R< 0.2, p=NS) or blood flow values (R=0.12). Analysis by vascular territory did not correlate with the degree of coronary stenosis (p=NS). Conclusions Lack of correlation between PET viability patterns, degree of epicardial stenosis and myocardial blood flow suggest that coronary anatomy can neither differentiate viable from necrotic myocardium nor predict the functional status of myocardial flow in patients with left ventricular dysfunction.

Palavras-chave : Positron-Emission Tomography; Cell Survival; Perfusion Imaging.