Objective: This study evaluated how much of the myocardium was hibernating in patients
with left ventricle dysfunction and/or comorbidities who planned to undergo either surgical
or interventional revascularization. Furthermore, this study also identified which irrigation areas of
the coronary arteries presented more scar and hibernating tissue.
Methods: At rest, Tc-99m MIBI SPECT and cardiac F-18 FDG PET/CT images collected between
March 2009 and September 2016 from 65 patients (55 men, 10 women, mean age 64±12) were retrospectively
analyzed in order to evaluate myocardial viability. The areas with perfusion defects
that were considered metabolic were accepted as hibernating myocardium, whereas areas with perfusion
defects that were considered non-metabolic were accepted as scar tissue.
Results: Perfusion defects were observed in 26% of myocardium, on average 48% were associated
with hibernation whereas other 52% were scar tissue. In the remaining Tc-99m MIBI images, perfusion
defects were observed in the following areas in the left anterior descending artery (LAD;
31%), in the right coronary artery (RCA; 23%) and in the Left Circumflex Artery (LCx; 19%)
irrigation areas. Hibernation areas were localized within the LAD (46%), LCx (54%), and RCA
(64%) irrigation areas. Scar tissue was also localized within the LAD (54%), LCx (46%), and RCA
(36%) irrigation areas.
Conclusion: Perfusion defects are thought to be the result of half hibernating tissue and half scar
tissue. The majority of perfusion defects was observed in the LAD irrigation area, whereas hibernation
was most often observed in the RCA irrigation area. The scar tissue development was more
common in the LAD irrigation zone.