Can nitrate-augmented SPET predict myocardial perfusion recovery after surgical treatment of ischaemic cardiomyopathy?

Abstract

Background and Aim: Tc-99m-sestamibi (MIBI) is a perfusion agent which is retained in the myocardium for many hours with a slow washout rate. Recently, a higher washout rate for MIBI has been reported in patients with acute myocardial infarction (AMI) after reperfusion treatment. In this study, we investigated the usefulness of MIBI myocardial SPECT in assessing stunned myocardium in AMI patients. Subjects and Methods: The subjects were 38 AMI patients whose infarct-related arteries were LAD and who had received successful reperfusion treatment within 24 hours from onset. A two-phase imaging of MIBI was performed at rest condition approximately 7 days after the onset of AMI. An I-123-BMIPP (BMIPP) myocardial SPECT was also performed about the same time as the MIBI. The SPECT images were divided into 17 segments and visual uptake was scored according to a 5-point scheme. The sum of scores in segments corresponding with infarct-related area was expressed as total score (TS). Washout score (WS) was defined as the difference in TS between an early image of MIBI and a delayed image of MIBI. Mismatch score (MS) was defined as the difference in TS between an early image of MIBI and an early image of BMIPP. Regional washout rate (RWR) in each coronary territory was calculated from polar map. Left ventriculography was performed at the time of reperfusion treatment and at the late stage (4-6 months after), and the improvement rate in regional wall motion (dRWM) was quantitatively evaluated by the centerline method.Results: TS in delayed images of MIBI showed strong correlation with TS in early images of BMIPP (R=0.935). Consequently, visual findings of these two images were very similar. Significant correlation was demonstrated between WS and MS (R=0.777). RWR in infarct areas were significantly higher than that in non-infarct areas (32.8 +/- 6.8% vs. 25.2 +/- 5.9%; P<0.0001). The dRWM showed significant correlations with RWR in infarct area, WS and MS. [...].