Abstract 15538: Referral to Coronary Angiography Subsequent to an Abnormal Stress-Only SPECT Study: Expanding the Concept Beyond the Normal Scan
BACKGROUND: Current standards are to perform rest imaging when the stress scan is abnormal, as no data exists as to diagnostic accuracy of stress only (SO) SPECT image. We therefore studied 145 consecutive patients who underwent stress only (SO) SPECT and were referred to coronary angiography (CA) within 30 days and no change in symptoms.
METHODS: From 1/2005 to 4/2013, 145 pts who had a SO SPECT and underwent CA were included. A summed stress score (SSS) of ≥3 for non-attenuation corrected (AC) and ≥ 2 for AC SPECT was defined as abnormal. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for significant CAD (≥70%) as well as in relation to single and multivessel CAD, gender, BMI, and stress modality was determined. Statistical significance was calculated using Chi Square and unpaired t test.
RESULTS: Average age and BMI was 59.7 ± 10.6 yrs and 30.2 ± 6.2 kg/m2 respectively. 70% were male, 29% had known CAD, 23% were diabetic, 70% had hypertension, 26% were smokers, 73% had dyslipidemia and 30% were stressed with a vasodilator. 99/145 had abnormal SO SPECT and the remaining 46 underwent CA for variety of clinical indications. 97/145 pts had significant CAD on CA. The mean radiation dose was 6.8 ± 3.4 mSv. The mean SSS of pts with abnormal SPECT and CA was significantly higher than those with abnormal SPECT but normal cors (10.8 ± 5.4 vs 6.4 ± 6.1, p=0.006). Overall sensitivity, specificity, PPV and NPV of SO SPECT was 91%, 77%, 89% and 80% respectively. Sensitivity was higher in male and pts with multivessel CAD while specificity was higher in female. The diagnostic accuracy among pt with BMI <30 vs ≥30, pharmacologic vs exercise and AC vs non AC SPECT was not statistically different (Table).
CONCLUSION: SO SPECT achieved high diagnostic accuracy in patients with multiple risk factors for CAD. This has important implications for improving efficiency, reducing costs, and reducing radiation exposure for patients referred for SPECT imaging.
- © 2013 by American Heart Association, Inc.