PACIFIC: First Head-to-Head Comparison of PET, SPECT, CCTA in Diagnosing CAD
Of the three most commonly used non-invasive techniques to evaluate myocardial perfusion or coronary artery stenosis severity, positron emission tomography (PET) had more diagnostic accuracy than either single photon emission computed tomography (SPECT) or coronary computed tomography angiography (CCTA), according to results from the PACIFIC Trial presented Aug. 29 at ESC Congress 2016 in Rome.
The single center study included 208 patients with suspected coronary artery disease (CAD). All patients underwent initial invasive coronary angiography, which showed 44 percent had hemodynamically significant CAD. Patients then received non-invasive PET, SPECT and CCTA as well as some “hybrid” combinations of PET and CCTA or SPECT and CCTA designed to combine functional and anatomical assessments.
Comparing results of these non-invasive results to the invasive results, investigators showed that PET was significantly more accurate (85 percent) for diagnosing coronary ischemia as compared to CCTA (74 percent) and SPECT (77percent). Sensitivity of the non-invasive approaches was 87 percent for PET, 90 percent for CCTA, and 57 percent for SPECT. Additionally, specificity was 84 percent for PET, 60 percent for CCTA, and 94 percent for SPECT. Diagnostic accuracy was not enhanced by either hybrid CCTA/SPECT or CCTA/PET, and instead resulted in an increase in false negatives and decrease in false positive results (p<0.001), according to investigators.
“At present, there is little consensus about the choice of non-invasive imaging modality, and European and U.S. guidelines do not advocate for any one over another,” said Ibrahim Danad, MD, from VU University Medical Center, Amsterdam, who presented the findings. “The vast majority of studies used invasive coronary angiography as a reference standard, which may lead to erroneous interpretations. These data represent the first comprehensive evaluation of CAD and will help to guide the clinician to choose the appropriate non-invasive test for his or her patients.”
“With the limited sample size, larger studies are needed to confirm these initial findings,” adds Kim A. Eagle, MD, MACC, editor in chief of ACC.org.
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