My goal is to become an exceptional health services investigator whose main research focus is to evaluate the efficacy and safety of non-invasive imaging strategies in the management of cardiovascular disease. I propose a mentoring plan and study program that will enable me to evaluate the impact and value of non-invasive imaging in the management of obstructive coronary artery disease (a disease caused by arterial blockages in the heart). Coronary artery disease (CAD) remains one of the most common causes of morbidity and mortality in Veterans and non-Veterans in the United States (U.S). In 2010, the estimated cost of CAD in the U.S., including hospitalizations and lost productivity, is approximately $503.2 billion. Diagnostic imaging accounts for much of the costs associated with patient care. The use of non-invasive testing, especially nuclear exams, has risen dramatically in the last three decades, but it is unclear whether patients are benefiting from more testing or merely receiving more radiation exposure. Routine evaluation of patients with suspected CAD currently requires an initial non-invasive functional test. If ischemia is suspected, cardiac catheterization is performed to identify potential arterial blockages. This paradigm is used to limit unnecessary exposure to the risks of an invasive procedure (e.g., cardiac catheterization) including arterial complications, arrhythmia (dangerous heart rhythms), stroke, and even death. Furthermore, it ensures access to limited resources and minimizes unnecessary costs. Recent studies in the general population suggest that the current paradigm may be potentially ineffective and may increase cancer risk. In a study of over 350,000 non-Veterans who were referred to a cardiac catheterization based on the current paradigm, only one-third had significant disease and benefitted from the procedure. Not only did two thirds of patients not benefit from the procedure, but they may also have been exposed to low dose radiation from non-invasive imaging tests (e.g., nuclear testing). Radiation exposure from nuclear testing has increased dramatically over the past three decades, potentially increasing cancer risk. These findings suggest that the impact and value of current strategies needs to be further evaluated and perhaps a new paradigm for the management of obstructive CAD is needed. To address this controversy, I will first need to determine the utilization pattern of non-invasive testing and the factors affecting utilization (Aim 1). This examination will enable me to determine whether variations in utilization also exist in the Veterans Affairs Health Care System. Then I will perform a cost-effective analysis using modeling and recent data from the literature, taking into account the amount of radiation exposure as a potential cancer risk (Aim 2). Finally, I will develop a clinical decision tool to guide VA care providers to select the most cost-effective strategy for the risk stratification and diagnosis of Veterans with obstructive CAD. I will also analyze outcomes before and after implementation of the clinical decision tool(Aim 3).

Public Health Relevance

Coronary artery disease (CAD) is highly prevalent among US Veterans and results in significant morbidity and mortality, including myocardial infarction, dangerous arrhythmias, heart failure and even death. Non-invasive imaging tests are the mainstay of diagnosis of CAD and contribute to significant costs to the Veterans Affairs Health Care System (VAHCS). Recent studies, however, have raised concerns regarding the effectiveness and safety of these non-invasive imaging tests. These concerns have yet to be addressed in the VAHCS. This proposal will benefit Veterans by determining factors affecting utilization and the most cost-effective imaging strategies for Veterans. Based on these findings, we will develop a clinical decision tool to help providers order the most appropriate test and measure outcomes before and after implementation.

National Institute of Health (NIH)
Veterans Affairs (VA)
Veterans Administration (IK2)
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HSR&D Career Development Award (CDA0)
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Veterans Admin Palo Alto Health Care Sys
Palo Alto
United States
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Chung, Kieran S; Nguyen, Patricia K (2018) Non-invasive measures of coronary microcirculation: Taking the long road to the clinic. J Nucl Cardiol 25:2112-2115
Lee, Won Hee; Nguyen, Patricia; Hu, Shijun et al. (2015) Variable activation of the DNA damage response pathways in patients undergoing single-photon emission computed tomography myocardial perfusion imaging. Circ Cardiovasc Imaging 8:e002851
Nguyen, Patricia K; Wu, Joseph C (2011) Radiation exposure from imaging tests: is there an increased cancer risk? Expert Rev Cardiovasc Ther 9:177-83