Detection of hibernated myocardium using intracoronary technetium-99m-sestamibi

Abstract

A possible limitation of intravenously administered perfusion tracers in detecting hibernating myocardium is their poor availability in low-flow areas. We 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 left anterior descending coronary artery, technetium-99m-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 dys-synergic area, previously characterized by a severe irreversible defect (less than 50% of peak activity) at rest-redistribution thallium SPECT ("mismatched pattern"); in patient 2, no uptake of sestamibi was detected in the dys-synergic 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 dys-synergic area was viable (hibernating), while neither wall motion nor thallium uptake improvement occurred in patient 2, confirming that most of the dys-synergic area was not viable (scar). We conclude that sestamibi retention in the dys-synergic 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.