Detention of hibernated myocardium using intracoronary technetium-99 m-Sestamibi

A possible limitation of intravenously administered perfusion tracers in detecting hibernating myocardium is their poor availability in low-flow areas. The authors have hypothesized that intracoronary administration might overcome such a limitation. In two patients with a previous anterior myocardial infarction and a severe residual stenosis of the anterior descending coronary artery, Technetium-99 m-Sestamibi (74 MBq) was selectively injected into the infarct-related coronary artery before successful PTCA. SPECT imaging was carried out 1 hour after the PTCA. In patient 1, evident tracer uptake was detected in the majority of the antero-apical dyssynergic area, previously characterized by a severe irreversible defect (less than 50% of peak activity) a rest-redistribution thallium SPECT ('mismatched pattern'); in patient 2, no uptake of Sestamibi was detected in the dyssynergic area showing a severe irreversible defect (less than 50% of peak activity) at rest-redistribution thallium SPECT, ('matched pattern'). Forty days after PTCA, contractile recovery as well as normalization of thallium uptake occurred in patient 1, confirming that most of the dyssynergic area was viable (hibernating), while neither wall motion nor thallium uptake improvement occurred in patient 2, confirming that most of the dyssynergic area was not viable (scar). The authors conclude that Sestamibi retention in the dyssynergic area after selective intracoronary administration correctly identified viable and scarred myocardium. The potential diagnostic value of intracoronary Sestamibi at the time of coronary angiography deserves to be validated as a possible alternative to other current procedures for detecting hibernating myocardium