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Open Access Research article

Utility of nuclear stress imaging for detecting coronary artery bypass graft disease

Basel Al Aloul12*, Mackenzi Mbai12, Selcuk Adabag12, Santiago Garcia12, Hoang Thai3, Steven Goldman3, William Holman4, Gulshan Sethi3, Rosemary Kelly12, Herbert B Ward12 and Edward O McFalls12

Author Affiliations

1 University of Minnesota, Minneapolis, MN, USA

2 Veterans Affairs’ Medical Center, Minneapolis, MN, USA

3 Veterans Affairs’ Medical Center, Tucson, AZ, USA

4 Veterans Affairs’ Medical Center, Birmingham, AL, USA

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BMC Cardiovascular Disorders 2012, 12:62  doi:10.1186/1471-2261-12-62

Published: 3 August 2012

Abstract

Background

The value of Single Photon Emission Computed Tomography stress myocardial perfusion imaging (SPECT-MPI) for detecting graft disease after coronary artery bypass surgery (CABG) has not been studied prospectively in an unselected cohort.

Methods

Radial Artery Versus Saphenous Vein Graft Study is a Veterans Affairs Cooperative Study to determine graft patency rates after CABG surgery. Seventy-nine participants agreed to SPECT-MPI within 24 hours of their coronary angiogram, one-year after CABG. The choice of the stress protocol was made at the discretion of the nuclear radiologist and was either a symptom-limited exercise test (n = 68) or an adenosine infusion (n = 11). The SPECT-MPI results were interpreted independent of the angiographic results and estimates of sensitivity, specificity and accuracy were based on the prediction of a graft stenosis of ≥70% on coronary angiogram.

Results

A significant stenosis was present in 38 (48%) of 79 patients and 56 (22%) of 251 grafts. In those stress tests with an optimal exercise heart rate response (>80% maximum predicted heart rate) (n = 26) sensitivity, specificity and accuracy of SPECT-MPI for predicting the graft stenosis was 77%, 69% and 73% respectively. With adenosine (n = 11) it was 75%, 57% and 64%, respectively. Among participants with a suboptimal exercise heart rate response, the sensitivity of SPECT-MPI for predicting a graft stenosis was <50%. The accuracy of SPECT-MPI for detecting graft disease did not vary significantly with ischemic territory.

Conclusions

Under optimal stress conditions, SPECT-MPI has a good sensitivity and accuracy for detecting graft disease in an unselected patient population 1 year post-CABG.

Keywords:
Coronary artery bypass grafts; CABG; Coronary artery imaging; Cardiac catheterization/intervention