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

Abstract

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

Effect of coronary artery bypass graft surgery on left ventricular systolic function

“…While the magnitude of decrease in LVEF was small (mean 3% reduction), which may not have any clinical significance, the change in EF ranged from −33% to 15%, meaning that some patients had a clinically significant decline in EF. A decrease in LV systolic function with CABG surgery may result from intra-operative global ischemia (15) or myocardial stunning (16), or from early post-operative graft failure (17). These results warrant confirmation in prospective studies with unselected patients.…”

Invasive angiography and revascularization in patients with stable angina following prior coronary artery bypass grafting: Results from the East Denmark heart registry

“…The use of FFR testing in bypass grafts, for instance, has not been subject to extensive prospective validation. Regarding the use of non‐invasive imaging in such patients, published studies in this area have been very small but have suggested comparable accuracy (74–82%) for the detection of graft stenoses . While a positive non‐invasive stress test was an independent predictor of subsequent revascularization, such testing overall had very limited specificity.…”

The Concordance between Myocardial Perfusion Imaging and Coronary Angiography in Detecting Coronary Artery Disease: A Retrospective Study in a Tertiary Cardiac Center at King Abdullah Medical City

“…Researchers claimed that the results of the myocardial perfusion imaging were not concordant with angiographic findings, which was possibly due to the nature of this disease (nonfixed lesion). In another study, the investigator examined the value of using SPECT-MPI to detect the graft disease after a coronary artery bypass surgery (CABG), and it was claimed that “SPECT-MPI has a good sensitivity and accuracy for detecting graft disease in an unselected patient population 1 year post-CABG under optimal stress conditions” (with the presence of variation in accuracy and sensitivity of SPECT-MPI between the exercise stress test and the pharmacological stress test) [ 14 ]. On the other hand, Shelley and his colleagues [ 15 ] have attempted to compare SPECT-MPI with multislice computed tomography (MSCT), and it was found that “whenever MSCT was negative, MPI was almost negative.” In addition, a study conducted by Delcour et al [ 16 ] included 48 patients with normal CAG and abnormal MPI who were followed up for at least 3 years from the conduction of MPI.…”