1010-65 Predicting Adverse Outcome in a Mixed Population with Exercise SPECT Sestamibi (MIBI) Scans

There is widespread use of MIBI for the diagnosis of coronary artery disease (CAD) because of favorable imaging characteristics including better tissue penetration and less attenuation with obesity or breast tissue. There is little data available on the utility of exercise SPECT MIBI in predicting long-term outcome. We sought to determine our ability at predicting adverse events in a typical population with comparable distribution of males and females. In 1992, 255 consecutive patients (126 female) had exercise SPECT MIBI scans for evaluation of chest pain syndrome, CAD, or myocardial infarction (MI). Acquisition of perfusion images was accomplished with a single head Sophy DS7 camera using 32 projections over a 180 degree body contour orbit at 25 seconds/step, and energy window peaked at 140 keV (20% symmetry). A low energy all purpose collimator was used and processing was performed on a Sophy computer. Clinical readings were reviewed and scored by independent observers as normal (NL), or abnormal (AB). Follow-up was performed by written questionnaire, telephone interview, and review of clinic charts. The events, non-fatal MI and cardiac death, were corroborated by chart review or physician contact when possible. Patients (pts) were excluded from analysis if they had revascularization within 1 month of imaging. The follow-up Interval was defined as time from scanning until an event, late revascularization, or patient response. Follow-up averaged 18 months and was ≈92% complete with no significant difference in response rate or time noted between gender or scan score. In total, there were 172 NL scans (i.e. 67%), and 83 AB scans (33%). Of the 255 pts, 2/172 NL, and 6/83 AB had clinical events. Statistical analysis using the Kaplan-Meier survival curve suggests a significant difference in event free survival between NL and AB scans with AB scans portending worse outcome (t = 8.0484, Chi square p l 0.005). Conclusion exercise SPECT MIBI scans do predict adverse outcome in a typical referral population with a high prevalence of women.