Abstract 553: Iodofiltic Acid I 123 SPECT Provides Incremental Diagnostic Value over Initial Clinical Information in Emergency Department Patients with Suspected Acute Coronary Syndrome
Objectives: Emergency department (ED) diagnosis of chest pain (CP) is problematic, and often requires hospital admission or prolonged observation. Iodofiltic acid I 123 (BMIPP) SPECT detects recent (≤ 30h) abnormalities in fatty acid metabolism from myocardial ischemia. We studied the incremental value of BMIPP over the initial diagnosis (InDx) of CP in the ED for identifying patients (pts) with acute coronary syndrome (ACS).
Methods: ED pts with CP consistent with ACS were enrolled in this open-label study at 9 centers. Prior MI or STEMI were exclusion criteria. Pts were injected with 0.5 mg of BMIPP (mCi range 2.5–5.4) within 30 hrs of CP cessation. BMIPP images were interpreted quantitatively. Clinical evaluation, serial ECGs and troponin (Tn), were performed in all pts, with stress MPI and/or angiography performed as clinically indicated. The InDx of “definite ACS” (D-ACS) or “definite or probable ACS” (DP-ACS) was based on presenting CP, ECG and Tn. Final diagnosis of D-ACS and DP-ACS was determined using data from all time points (except for BMIPP). D-ACS was defined as elevated Tn or revascularization. DP-ACS was defined as the presence of either D-ACS, significant disease on angiography (>50% stenosis) or ischemia on stress SPECT.
Results: Of the 103 pts, 55% were male with mean age (range) of 56 years (29–84). For D-ACS, quantitative BMIPP plus InDx increased sensitivity by 35% to 97% (p<0.01) and non-significantly increased NPV by 14% to 98% (Table⇓). For DP-ACS, quantitative BMIPP imaging plus InDx increased sensitivity by 40% to 88% (p<0.001) and non-significantly increased NPV by 18% to 88%.
Conclusion: Adding BMIPP to ED InDx increased sensitivity and NPV for detecting D-ACS and DP-ACS. BMIPP may have significant clinical and economic value because of its improved early identification of high-risk ED CP patients.