Short-Term Prognostic Value Of Rest Tc99m-Mibi Gated Spect After Acute Non-Q Wave Myocardial Infarction

Aim: The purpose of this study is to determine the short–term prognostic value of technetium 99m methoxyisobutylisonitrile gated single photon emission computed tomography (Tc99m–MIBI Gated SPECT) in patients with acute Non–Q wave myocardial infarction (NQMI) in 30 days.
Methods: We identified 36 patients who underwent rest Tc99m–MIBI Gated SPECT and who were followed-up 30.65±0.49 days after first a NQMI. 21 patients were males, 15 females, with a mean age of 60.30±10.17 years. Rest Tc99m–MIBI Gated SPECT were performed within 48 (30.7±2.3) hours of admission to the coronary care unit after acute myocardial infarction (MI). The left ventricular ejection fraction (LVEF), end diastolic (EDV) and end systolic volumes (ESV), and summed rest score (SRS) and extent score (ES) were assessed using rest Tc99m–MIBI Gated SPECT.
Results: Rest Tc99m–MIBI Gated SPECT parameters and clinical datas were analyzed and divided two group according to prognosis, as new cardiac event (poor prognosis) and stable stuation (good prognosis). During follow-up, 12 patients (33%) had a new clinical event, [4 congestive heart failure (11%), 7 revascularization (19%) and 1 reinfarct (2%)], whereas 24 patients (66%) showed a good outcome. There were significant differences LVEF, EDV, ESV, SRS and ES values between poor and good prognosis group (p=0.011, p=0.016, p=0.017, p<0.001, p<0.001 respectively). The hazard ratio for new cardiac events were 7.6 for patients with rest LVEF lower than 40% (Relative Risk (RR)=7.66, Confidence Intervals (CI) 1.60 to 35.90, p=0.005), for ESV>70 ml (RR=5.31, CI 1.17 to 24.14, p=0.027), SRS≥7 (RR=7.00, CI 1.25 to 39.14, p=0.032) and ES≥3 (RR=6.59 CI 0.72 to 60.02, p=0.037).
Conclusion: Left ventricular parameters (LVEF, ESV) and perfusion scores (SRS, ES) which obtained by rest Tc99m–MIBI Gated SPECT, provide useful information in the prediction of future cardiac events after NQMI in 30 days.

Keywords
Non-Q wave myocardial infarction, short-term prognosis, Tc99m-MIBI Gated SPECT.