Assessment of myocardial necrosis immediately after intracoronary thrombolysis by intracoronary injection of technetium-99m pyrophosphate.

To assess myocardial necrosis immediately after intracoronary thrombolysis, thallium-201 (TL-201) and technetium-99m pyrophosphate (Tc-99m PYP) were injected simultaneously into the coronary artery in 25 patients with acute transmural myocardial infarction. In 17 of the 25 patients, the occluded coronary artery was reopened. Minutes after the intracoronary injection of Tc-99m PYP into the reopened coronary artery a localized accumulation was seen within the area of the Tl-201 defect in all patients. Control intravenous scintigraphy, which was performed in 8 of these 17 patients 1-6 days later, and in 2 patients 18 and 42 days after infarction, revealed a Tc-99m PYP spot similar to that of the acute intracoronary Tc-99m PYP scintigram in all 10 patients. In the 8 of the 25 patients, in whom intracoronary thrombolysis failed, no localized Tc-99m PYP accumulation was seen after injection into the infarct vessel. In 5 of these patients, a control intravenous scintigram, performed 1-8 days later, resulted in a Tc-99m PYP spot in the area of the Tl-201 defect. We conclude that, in the presence of therapeutic or spontaneous reperfusion, Tc-99m PYP scintigraphy may provide a useful method of assessing myocardial necrosis during the early stage of an acute myocardial infarction.