Risk Assessment and Predictive Value of Coronary Artery Disease Testing

Abstract

This review highlights and compares risk assessment, predictive accuracy, and economic outcomes for 3 commonly applied cardiac imaging procedures: stress myocardial perfusion SPECT or PET and coronary CT angiography (CCTA). This review highlights an expansive evidence base for stress myocardial perfusion imaging and reveals a decided advantage for higher-risk patients, notably those who have established coronary artery disease (CAD). It is likely that the use of CCTA will continue to expand, particularly for patients with more atypical symptoms and patients with a lower likelihood of CAD. Despite a high level of evidence, comparative research is not available across modalities that could definitively drive utilization of cardiac imaging modalities. Evi dence about the accuracy of a variety of noninvasive imaging tests for the identification of at-risk patients with known and suspected coronary artery disease (CAD) has been evolving. Most of the early published research on noninvasive cardiology, from the 1980s and early 1990s, focused on the diagnostic accuracy of a test. More recent research has focused on evaluating the ensuing risk in patients with normal and abnormal cardiac imaging findings. Further exploration has been aimed at the graded or directly proportional relationships between the extent and the severity of imaging risk markers and major adverse cardiovascular events. These relationships highlight a common theme throughout the literature of ever-increasing and worsening cardiac event risk with more extensive and severe imaging abnormalities. More recent topics in the prognosis literature are the utility of new technology, such as coronary CT angiography (CCTA), and its accuracy compared with that of conventional testing, such as stress nuclear imaging. For this report, we compare risk assessment, predictive accuracy, and economic outcomes for 3 commonly applied cardiac imaging procedures: stress myocardial perfusion SPECT or PET and CCTA. We further highlight the potential value of hybrid imaging with PET/CT or even sequential imaging with SPECT plus CT. CORRELATION BETWEEN MYOCARDIAL ISCHEMIA AND CORONARY ANATOMYEarly research focused on the accuracy of stress nuclear imaging for detecting obstructive coronary stenosis. Lessons learned from these evaluations were that the detection of obstructive stenosis was related to the severity of the stenosis, collateral flow, and underlying endothelial function. Documentation of high rates of false-positive results (i.e., ischemia with no obstructive CAD) with stress myocardial perfusion may be related to vascular dysfunction, an early marker of atherosclerosis. In addition, normal stress perfusion results in patients with CAD are related to many factors, including collateral blood flow or prior coronary revascularization. It is for these reasons that much of the recent imaging research has focused on risk determination. However, for discussion purposes, it is helpful to understand the relationship between ischemia and coronary anatomy. INDUCIBLE ISCHEMIA D...

PET Assessment of Myocardial Perfusion Reserve Inversely Correlates with Intravascular Ultrasound Findings in Angiographically Normal Cardiac Transplant Recipients

“…13 N-ammonia dynamic PET blood flow measurements include integrated vasodilation capacity, endothelium-related vasomotor function, and epicardial conduit vessel function (42,43). MBF and MPR not only can provide important diagnostic and prognostic information (10)(11)(12)(20)(21)(22)(23)(24)(25) but also can be used as a surrogate endpoint to assess therapeutic response (44-48) and to guide interventions aimed at reducing cardiac risks or ischemic burden in subjects with native coronary artery disease (49).…”

“…13 N-ammonia dynamic PET blood flow measurements include integrated vasodilation capacity, endothelium-related vasomotor function, and epicardial conduit vessel function (42,43). MBF and MPR not only can provide important diagnostic and prognostic information (10)(11)(12)(20)(21)(22)(23)(24)(25) but also can be used as a surrogate endpoint to assess therapeutic response (44-48) and to guide interventions aimed at reducing cardiac risks or ischemic burden in subjects with native coronary artery disease (49).CAV is a progressive process involving the epicardial and microvascular coronary systems. Conflicting results in IVUS-and Doppler-derived coronary flow reserve studies (7,8,(28)(29)(30)(31)(32)(33)(34)(50)(51)(52) suggest that the correlation between endothelial dysfunction and coronary changes is complex.…”

“…Stress myocardial perfusion images, including SPECT and PET, have been recognized as key diagnostic methods to evaluate coronary artery disease (9)(10)(11)(12). Stress myocardial SPECT, in comparison with invasive coronary angiography, frequently underestimates the extent and severity of CAV (8,(13)(14)(15)(16).…”

Role of coronary artery calcium score for risk stratification in patients with non significant perfusion defects by myocardial perfusion single photon emission computed tomography

“…More extensive and severe perfusion defects are associated with up to 5% of the annual cardiac events rates [11][12][13]. The last subset is decidedly of high risk and favors the use of aggressive anti-ischemic therapy and consideration of coronary angiography and revascularization [14].…”

Non-Invasive Assessment and Clinical Strategy of Stable Coronary Artery Disease by Magnetic Resonance Imaging, Multislice Computed Tomography and Myocardial Perfusion SPECT

“…24 Conversely, critical stenosis in the left main coronary artery, which might be overlooked by myocardial perfusion SPECT, correlated with high cardiac event rates. [25][26][27] When MSCT findings did show equivocal or mildly abnormal in patients without high coronary risks, the next recommendations are so far uncertain. Furthermore, we do not have enough data whether or not the information of MSCT angiography improve patients' outcome.…”