CORONARY ANGIOGRAPHIC RATES AFTER STRESS SINGLE-PHOTON EMISSION COMPUTED TOMOGRAPHIC SCINTIGRAPHY

Background, There is speculation that coronary angiography may be over used for the assessment of coronary artery disease, Because of its pro ved ability to differentiate high- and low-risk subsets of patients wi th coronary artery disease, myocardial perfusion scintigraphy should b e an effective strategy in patient selection for angiography, This ret rospective clinical study analyzed the relation between scintigraphic findings and subsequent angiography. Methods and Results. Coronary ang iographic rates were determined by following up on all stress single-p hoton emission computed tomographic (SPECT) myocardial perfusion studi es performed in a cardiology practice nuclear laboratory during a 26-m onth interval, All patients were followed up for at least 3 months; me an follow-up was 8.9 months, Subsequent angiography was determined fro m catheterization laboratory logs, medical records, and telephone cont act, Scintigraphic studies were graded according to presence or absenc e of reversible perfusion defects, affected coronary territories, and lung uptake of Tl-201, Scans were categorized high risk if more than t wo of the following three criteria were met: reversibility of left ant erior descending or multivessel distributions or abnormal lung uptake of thallium, Of 4162 studies, 60% had reversible perfusion defects, Of such studies, 32% were followed up by angiography versus 3.5% without reversible defects, Among studies with reversible defects, the subseq uent angiography rate was 60% for those showing high-risk reversibilit y, compared with 9% for all other studies demonstrating reversibility, Multivariate logistic regression identified high-risk reversibility ( odds ratio 20.96) and any reversibility (odds ratio 8.22) as the stron gest predictors of angiography, Other correlates of lesser statistical significance were angina and absence of prior infarction or coronary bypass. Conclusion, In this large retrospective study, the results of SPECT scintigraphy overpowered all other clinical and treadmill charac teristics in determining the likelihood of subsequent coronary angiogr aphy, Only rarely were patients categorized as relatively low risk by scintigraphy referred for angiography, As such, SPECT scintigraphy as used in a private practice, self-referral environment appears to be ef fective in stratifying potential candidates for coronary angiography.