Characterization of viability, scarring and hibernation of the myocardium supplied by epicardial coronary arteries with low flow grades

Objective: The aim of this study was to analyse the relationship between reduced coronary artery flow and myocardial viability, scarring and hibernation.Patients and methods: Coronary flow grades and collateral vessels were scored using the thrombolysis in myocardial infarction trial (TIMI) and the Rentrop and Cohen scoring systems, respectively. 13N-ammonia and fluorine-18-fluorodeoxyglucose (18F-FDG) are the perfusion and metabolic markers on PET, respectively. The left ventricle was divided into three coronary territories. The area with the highest 13N-ammonia uptake was considered the reference region. Myocardial regions with 18F-FDG uptake of at least 50% of the reference region were considered viable and those with 18F-FDG uptake less than 50% of the reference region were considered scarred. Hibernation was considered present if the viable myocardium had significant wall motion abnormality.Results: There were 80 (71 males) patients with 240 myocardial territories. TIMI 2–3 arteries supplied 151 regions (group A), and 89 regions were supplied by TIMI 0–1 arteries (group B). Viable myocardium was present in 140 (93%) regions of group A and in 76 (85%) regions of group B (P=0.068). Scarring was present in 40 (26%) regions in group A and in 49 (55%) regions in group B (P<0.0001). Wall motion data were available in 215 regions: 133 regions in group A and 82 regions in group B. Hibernating myocardium was predicted in 36 (28%) regions in group A and in 34 (41%) regions in group B (P<0.05).Conclusion: Myocardial regions supplied by arteries with TIMI 0–1 are characterized by significantly increased incidence of hibernation and scarring. Video abstract: http://links.lww.com/NMC/A115