Quantification of Tc-99(m)-sestamibi and I-123-BMIPP uptake for predictingfunctional outcome in chronically ischaemic dysfunctional myocardium

Little is known about the usefulness of free fatty acid scintigraphy for as sessing viability in chronic ischaemic heart disease. To investigate this, we quantified the uptake of Tc-99(m)-sestamibi and I-123-BMIPP at rest twic e within 6 months in 20 patients with chronic ischaemic left ventricular dy sfunction and infarction. Four patterns of the relative distribution of bot h tracers were observed and classified as normal, mismatched, matched and s car. The proportion of the left ventricular surface corresponding to each p attern was expressed as the percentage of the total surface using a polar m ap, between the two studies, the patients either underwent revascularizatio n or were treated conservatively. The quantitative results were compared wi th those of dobutamine stress echocardiography (DSE) in arterial territorie s with resting contractile dysfunction and correlated with the evolution of regional and global function at follow-up. At baseline, 25 arterial territ ories were analysed. Using sestamibi, on average one-third of their surface was considered to be normally perfused. No clear association was found bet ween the percent normally perfused surface and the DSE findings. Adding BMI PP and using a value of >7% of the arterial surface with BMIPP lower than s estamibi (mismatch) as the cut-off for the significance of viability, 14 of 18 mismatched regions were considered viable by DSE, and six of seven with <7% mismatched surface or matching were not. Fifteen patients were viable, of whom 13 were revascularized (16 territories). At follow-up, global func tion improved in 11 of the 15 viable patients, all in the revascularized gr oup. Regional improvement was noted in 11 of 16 revascularized territories, and was associated with a significant increase in sestamibi and BMIPP upta ke and in the percent normally perfused myocardial surface. In the five pat ients without significant viability, no functional deterioration or changes in the quantitative parameters were observed during treatment. The results suggest that quantitative analysis of the uptake of sestamibi and BMIPP is a reliable method to objectively assess the presence of myocardial viabili ty in chronic ischaemic heart disease and to predict functional improvement after revascularization. ((C) 1999 Lippincott Williams & Wilkins).