Clinical significance of mild inferolateral wall ischemia of the left ventricle on 99mTc-MIBI myocardial perfusion single photon emission computed tomography (SPECT).

Introduction: Mild ischemia in the inferolateral wall on myocardial perfusion imaging is seen frequently in practice. The aim of this study is to assess the importance of the above issue on myocardial perfusion SPECT with coronary angiography.

Patients And Methods: All patients enrolled in this study exhibited mild ischemia of the inferolateral wall on myocardial single photon emission computed tomography (SPECT) with 99mTc-MIBI, using the 20 left ventricular segments model. Each patient completed a questionnaire, including type of chest pain, risk factors, and previous examinations, and all cases were followed up for one year. Luminal stenosis of >50% was classified as significant stenosis on coronary angiography. A p value < 0.05 was considered statistically significant.

Results: During investigation, 105 cases had mild ischemia on myocardial perfusion imaging (MPI) of which 36 subjects (22 male and 14 female) underwent coronary angiography. The mean age was 56.62±10.23 years old (age range: 36-73 years). The inferolateral wall was compared to the left circumflex (LCX) territory. Nineteen out of 36 (52.7%) cases had stenosis in the LCX. Twenty-three of 105 (21.90%) underwent revascularization during the one year follow up. In multiple logistic regressions, with LCX stenosis on angiography as the dependent variable, only abnormal MPI was independently associated significantly.

Conclusions: The findings of the study may indicate that even a mild perfusion defect in the inferolateral wall should be carefully managed, especially in high-risk subjects for coronary artery disease.