Comparative prognostic value of automatic quantitative analysis versus semiquantitative visual analysis of exercise myocardial perfusion single-photon emission computed tomography

Objectives. The purpose of this study was to determine the prognostic value of automatic quantitative analysis in exercise dual-isotope myocardial per fusion single-photon emission computed tomography (SPECT) and to compare th e prognostic value of quantitative analysis to semiquantitative visual SPEC T analysis. Background. Extent, severity and reversibility of exercise myocardial perfu sion defects have been shown to correlate with prognosis, However, most stu dies examining the prognostic value of SPECT in chronic coronary artery dis ease (CAD) have been based on visual analysis by experts. Methods. We studied 1,043 consecutive patients with known or suspected CAD who underwent rest Tl-201/exercise Tc-99m sestamibi dual-isotope myocardial perfusion SPECT and were followed up for at least 1 year (mean 20.0 +/- 3. 7 months). After censoring 59 patients with early coronary artery bypass gr afting or percutaneous transluminal coronary angioplasty, <60 days after nu clear testing, the final population consisted of 984 patients (36% women, m ean age 63 +/- 12 years). Results. During the follow up period, 28 hard events (14 cardiac deaths, 14 nonfatal myocardial infarctions) occurred. Patients with higher defect ext ent (>10%), severity (>150) and reversibility (>5%) by quantitative SPECT d efect analysis, as well as those with an abnormal scan (>2 abnormal segment s, summed stress score >4 and summed difference score >2) by semiquantitati ve visual SPECT analysis, had a significantly higher hard event rate compar ed to patients with a normal scan (p < 0.001). With both visual and quantit ative analyses, hard event rates of approximately 1% with normal scans and 5% with abnormal scans (p > 0.05) were observed over the 20-month follow up period. A Cox proportional hazards regression model showed that chi-square increased similarly with the addition of quantitative defect extent and vi sual summed stress score variables after considering both clinical and exer cise variables (improvement chi-square = 11 for both, p < 0.0007). There we re no significant differences in the areas under receiver operating charact eristic curves between quantitative and visual analysis (p > 0.70). Linear regression analysis also indicated that quantitative assessments correlated well with visual semiquantitative assessments. Conclusions. The findings of this study indicate that automatic quantitativ e analysis of exercise stress myocardial perfusion SPECT is similar to semi quantitative expert visual analysis for prognostic stratification, These fi ndings may be of particular clinical importance in laboratories with less e xperienced visual interpreters. (J Am Coll Cardiol 1998;32:1987-95) (C) 199 8 by the American College of Cardiology.