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ACC/AHA Appropriate Use Criteria recommend performing stress myocardial perfusion imaging (MPI) for intermediate to high-risk patients presenting with syncope (Level A7), but not for low-risk patients (level I3). However, there are limited data to support these recommendations. We investigated the diagnostic utility of stress MPI for patients without a history of CAD presenting with syncope.
From the Cleveland Clinic IRB approved MPI database, we identified consecutive patients without known diagnosis of CAD, who had undergone stress MPI between 2006-2012 for workup of syncope. For patients with abnormal MPI, coronary angiograms (LHC) were reviewed if performed. All-cause death was determined using SSDI master file. Binary regression analysis was performed to assess independent predictors of abnormal MPI.
There were 700 patients (mean age 62±15years, 55% female) who had undergone stress MPI; 659 (94%) with normal perfusion. Of the 41 (6%) with abnormal MPI, 18 had subsequent LHC with 9 true positive (overall yield 1.3%). Assuming that those who did not have LHC (n=23) had true positive stress test, the yield would be 4.6% (likely an overestimation). On multivariate binary regression analysis, EF <50% (OR 14.2 [6.9,29]) and age ≥65 yrs (OR 2.4 [1.2,4.8]) were the only independent predictors of abnormal MPI. Among those with EF ≥50% and age <65 years (n=348), there were 9 abnormal MPI, 6 LHC and only 1 positive angiogram (yield 0.3-1.1%). Among those EF <50% or age≥65 yrs, there were 8 positive LHC (yield 2.3%-7.9%). Over a 2.6 year median follow-up time, 45 patients (5 with abnormal MPI) died. There was no difference in outcomes between those who underwent LHC vs. those who did not (2/18 vs. 3/23, log-rank P= 0.9). Also, there was no significant difference in annual mortality between those with normal and abnormal MPI (2.3% vs. 3.3%, respectively, log-rank P=0.3).
Stress MPI for evaluation of syncope of patients without known CAD, with EF≥50% and age <65 years, has a very low yield and is inappropriate. For those with EF <50% or age ≥ 65 years, 2.3-7.9 % will have abnormal MPI; a relatively low diagnostic yield. Revision of the appropriateness criteria might be in order.
Poster Sessions, Expo North
Sunday, March 10, 2013, 9:45 a.m.-10:30 a.m.
Session Title: SPECT: Appropriate Use Criteria and Role in Specific Populations
Abstract Category: 21. Imaging: Nuclear
Presentation Number: 1229-361
- 2013 American College of Cardiology Foundation