Severity and extent of perfusion defects provoked by transient coronary occlusion compared with myocardial damage observed after infarction.

A peripheral perfusion tracer injection at the time of coronary occlusion during percutaneous transluminal coronary angioplasty (PTCA) may delineate the myocardial 'area at risk' related to a given artery. To evaluate the location, size and severity of the corresponding scintigraphic defects, we conducted a prospective study of 36 patients who received a 99 Tc m -sestamibi injection during single-vessel coronary angioplasty (PTCA=18 LAD, 16 RCA and 2 LCX) followed by SPET. For comparison, a reference group of 36 successive patients examined during the early phase of myocardial infarction (MI), matched for the same vascular territories (18 anterior, 16 inferior and 2 lateral), were analysed in the same way after standard stress/reinjection 201 Tl SPET. The imaging characteristics of both groups showed excellent agreement as well degree of uptake defects, in terms of topography and extent. A defect index, taking into account both size and severity, was in the same range for PTCA and MI patients (mean±standard deviation): for LAD vs anterior=28.4±13.5% (PTCA), 27.1±12.2% (MI-stress) and 24.2±10.0% (MI-reinjection); for RCA vs inferior =15.5 ± 10.2% (PTCA), 14.7±9.7% (MI-stress) and 13.2 ±8.2% (MI-reinjection). Sectoral correlations between PTCA and MI groups were also highly significant.