Quantitative Analysis Using Overlap Images with Technetium-99m Pyrophosphate Thallium-201 Dual-isotope SPECT to Evaluate Microvascular Reperfusion Injury Following Successful Coronary Intervention in Patients with Acute Myocardial Infarction

Abstract

We evaluated the extent of reperfusion injury (RI) following successful coronary intervention quantitatively and non-invasively using technetium-99m pyrophosphate (Tc-PYP) /thallium-201 dual-isotope single photon emission computed tomography (SPECT) . Tc-PYP/thallium-201 SPECT was performed 48 hours after coronary intervention in 67 patients (62.6±12.1 yr) who had undergone successful coronary intervention (TIMI grade 3) in the infarct-affected left anterior descending coronary artery within 6 hours after acute anteroseptal myocardial infarction. The infarct-affected region, which was defined quantitatively by a>55% uptake of Tc-PYP, was considered as showing RI if the recovery of myocardial perfusion was defined quantitatively by <60% uptake of thallium-201. Left ventriculography was performed immediately after intervention and at the 6-month follow-up. These clinical parameters were compared between patients with and without RI. RI was presented in 32 of the 67 patients. Electrocardiographic ST-segment elevations did not return to normal immediately after intervention in the patients with RI as compared to the patients without RI (62.5% of 20 patients versus 25.7% of 9, P<0.01) . The patients with RI had larger infarcts (Unit/L) (5490±3002 versus 2506±2074, P<0.0001), more severe left ventricular function (43±11.8% versus 50.2±10.2%, P<0.05), and larger end-diastolic left ventricular dilatation at the 6-month follow-up (mL/m2) (101±27.2 versus 85.2±24.1, P<0.05) than the patients without RI. This study therefore demonstrates that RI occurring soon after successful coronary intervention following acute myocardial infarction can be detected quantitatively by overlap SPECT images of Tc-PYP/thallium-201.