Early positive technetium-99m stannous pyrophosphate images as a marker of reperfusion after thrombolytic therapy for acute myocardial infarction

Abstract

Fourteen patients with transmural acute myocardial infarction (AMI) were treated with intravenous streptokinase a mean of 4 ± 1 hours after chest pain and underwent technetium-99m stannous pyrophosphate (Tc-99m-PPi) imaging 7 ± 2 hours after the onset of chest pain. The early Tc-99m-PPi images were obtained to test the hypothesis that an early, strongly abnormal Tc-99m-PPi image suggests reperfusion. Eleven of 14 patients had early peaking (within 16 hours) serum creatine kinase isoenzyme levels (CK-B) at a mean of 11 ± 3 hours. Ten of 14 patients had 3+ or 4+ acute Tc-99m-PPi images. Eight of 11 patients had patent infarct-related vessels at cardiac catheterization 15 days after AMI. One patient who had both an early positive Tc-99m-PPi image and CK-B peak level had an occluded infarct-related artery at catheterization. Acute left ventricular (LV) ejection fraction (EF) by radionuclide ventriculography was compared with LVEF on day 15, and improved from 0.37 ± 0.13 to 0.50 ± 0.16 (p = 0.004) in the 10 patients with strongly positive acute Tc-99m-PPi images. LVEF also improved from 0.37 ± 0.12 to 0.49 ± 0.15 (p = 0.003) in the 11 patients with early peaking serum CK-B values. Three patients without evidence of reperfusion failed to improve the LVEF from the initial value to the one obtained at hospital discharge. Six control patients had acute Tc-99m-PPi images 10 ± 2 hours after chest pain; none had strongly positive acute Tc-99m-PPi images, and the mean time to peak CK-B was 19 ± 5 hours. Strongly positive early Tc-99m-PPi images may be as reliable as early peaking CK-B in predicting successful reperfusion in patients receiving intravenous streptokinase therapy for AMI.