Gated SPECT evaluation of the relationship between admission troponin I, myocardial salvage, and functional recovery in acute myocardial infarction treated by abciximab and early primary angioplasty.

Abstract

Using gated SPECT, we evaluated the relationship between admission troponin I, risk area, and myocardial salvage in patients with a first myocardial infarction treated with abciximab and primary percutaneous coronary intervention within 6 h. In 43 patients, (99m)Tc-sestamibi was injected before primary percutaneous coronary intervention. Gated SPECT was acquired immediately thereafter and was repeated 7 and 30 d later. The initial risk area and subsequent infarct size were expressed as a percentage of the left ventricle; salvage index was the ratio between salvaged myocardium and initial risk area; left ventricular ejection fraction was calculated using the quantitative gated SPECT software. On admission, 20 patients showed elevated troponin I and had a larger risk area (P < 0.03) than did the group with normal troponin I. Infarct size at 30 d (15% +/- 12% vs. 13% +/- 13%) and salvage index (0.63 +/- 0.27 vs. 0.60 +/- 0.28) were not significantly different between the 2 groups. Ejection fraction was lower in the group with high troponin I on admission (36% +/- 10% vs. 41% +/- 11%, P < 0.05) and at 7 d (41% +/- 11% vs. 48 +/- 10, P < 0.03). At 30 d, improvement was greater in the group with high troponin I, and ejection fraction became comparable. Patients with high troponin I on admission have a larger initial risk area, but if they undergo primary percutaneous coronary intervention within 6 h and are treated with abciximab, myocardial salvage and functional recovery are similar to those observed in patients with normal troponin I, and no unfavorable relationship between high troponin I values on admission and myocardial salvage is registered.