|Ramesh K Adiraju*|
|Corresponding Author: Ramesh K Adiraju, RENU-CA Research Institute, Bristol, PA, USA|
|Received: December 04, 2017; Accepted: February 21, 2019; Published: August 10, 2019;|
|Citation: Adiraju RK. (2019) Cost Effective Coronary Care – A Novel CAD Assessment Protocol. J Cardiol Diagn Res, 2(2): 40-60.|
|Copyrights: ©2019 Adiraju RK. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.|
According to the Centers for Disease Control and Prevention, heart disease is the number one killer in America today. Nearly 2,400 people die each day from heart and blood vessel diseases and more than 7 million Americans have suffered a heart attack in their life time, according to American Heart Association data. Around 500,000 of these individuals will experience recurrence in a year. More than two million patients are triaged and treated for acute coronary syndrome in emergency wards across the country each year. These statistics are increasing by the day. A significant amount of research has therefore been devoted to screening for coronary artery disease (CAD) and to the delineation of mild and moderate from significant CAD disease. Despite the expensive and elaborate testing modalities that are being utilized, the incidence of sudden coronary events and cardiac death is still the leading cause of mortality and disability in the US. Therefore, coronary angiography is still the gold standard to identify significant CAD. With increased coronary angiography, there is increased coronary angioplasty. Hence, CAD is also the number one offender of healthcare spending. Unfortunately, despite the extensive investment in high cost modalities for differentiating mild to moderate CAD from significant CAD, no clear confidence has been instilled in cardiologists to safely avoid unnecessary catheterizations and coronary angioplasties. Hence, the need exists for a cost effective, reliable, non-invasive and universally easy to use modality to differentiate mild to moderate CAD from significant CAD. In this manuscript, we introduce a novel noninvasive coronary ischemia screening and CAD evaluation protocol using the CS-100 (Cardio Scan–100) Frequency Cardiograph (FCG) analysis system.
Keywords: CAD, Acute coronary syndrome, Coronary care, Cardio Scan–100
Acute coronary syndrome (ACS) is the umbrella term for clinical presentations of different stages of myocardial ischemia, ranging from angina/unstable angina (USA) with mild to moderate coronary artery disease (CAD) to acute ST-segment elevation myocardial Infarction (STEMI). Coronary Artery Disease (CAD) with plaque build-up in the coronary arteries compromises myocardial blood flow and modifies myocardial compliance, contractility, and blood flow dynamics. Coronary insufficiency can be from mechanical obstruction due to plaque build-up or from abnormal vasoreactivity due to vascular endothelial cell dysfunction and vascular inflammation. Abnormal vascular wall homeostasis with low vascular wall nitric oxide concentration and increased free radical (reactive oxygen species-ROS) pool occurs from dysautonomia-induced endothelial cell dysfunction. These are dynamic modifications that can be difficult to quantify. Abundant laboratory evidence indicates that inflammation plays a major role in all stages of atherosclerosis. Clinical evidence from several prospective studies demonstrates that inflammatory biomarkers independently predict vascular disease risk with a magnitude of effects as significant as increased blood pressure or high cholesterol. Prospective analysis from JUPITOR trial data indicate that achieving low levels of inflammation may be as important as achieving low levels of LDL-c cholesterol . JUPITOR data prospectively confirms data from several prior studies including CARE, AFCAPS/TexCAPS, PROVE IT, TIMI22, A to Z, REVERSAL. These trials corroborate laboratory evidence that anti-inflammatory processes reduce cell adhesion, monocyte recruitment at the arterial wall, augmented expression of the transcription factor KLF2 with consequent migration of inflammatory and thrombotic mediators, altered smooth muscle migration and reduction in IL-6 and other cytokines triggering plaque development.
Extensive research and a plethora of non-invasive testing modalities such as nuclear stress testing with Dobutamine Stress ECHO (DSE), SPEC imaging, pharmacologic stress testing with imaging, positron emission tomography (PET) imaging, coronary computed tomography angiography (CCTA) and coronary calcium scoring are some of the newer modalities that are being investigated to assess CAD and delineate mild to moderate CAD from significant CAD. This differentiation has both prognostic and therapeutic value. While significant CAD has a strong correlation to mortality and morbidity, mild to moderate CAD has good long-term prognosis with medical management alone. Fear of missing the monster (significant CAD) has driven research and the cost of caring for patients with CAD. Unfortunately, despite the extensive investment in high cost modalities for differentiating mild to moderate CAD from significant CAD, no clear confidence has been instilled in cardiologists to safely avoid unnecessary catheterizations and coronary angioplasties. This has been clearly demonstrated in the recent National Cardiovascular Registry (NCDR) data. Retrospective NCDR registry analysis of >400,000 positive non-invasive coronary ischemia tests found obstructive CAD association in only 38% overall . In female patients, particularly, only 33% had obstructive CAD, while >55% had normal angiograms. Appropriate use criteria (AUC) and unnecessary angioplasty recommendations generated by ACC and AHA, based on NCDR registry findings, have been arguably debated by interventionists for lack of high specificity and sensitivity in the available modalities to delineate false positivity and prevent false negative results. This forces interventional cardiologists to err on the side of safety. Hence, the need exists for a cost effective, reliable, non-invasive and universally easy to use modality to differentiate mild to moderate CAD from significant CAD.
Recent NCDR registry 2010 data analysis by Patel et al.  demonstrated poor yield from non-invasive testing in identifying significant CAD by coronary angiography and identified coronary angiography as the culprit for wasted healthcare dollars and demonstrated poor health care delivery. The American Heart Association (AHA) and the American College of Cardiology (ACC) therefore updated practice guidelines and performance measures for CAD to help clinicians adhere to standard of care. Appropriate use criteria (AUC) were developed by a task force from ACC to limit overuse of angiography and revascularization procedures. This was prompted due to recent literature demonstrating comparable mortality and morbidity between aggressive medical management and coronary revascularization. The cost for revascularization has skyrocketed in the last three decades. Despite the widespread use of percutaneous coronary interventions (PCI), the appropriateness of these procedures in contemporary practice is unknown and the mortality from CAD has not been affected by PCI. Based on this premise, there was a recent prospective study conducted to evaluate appropriateness of PCI highlighting inappropriate use of PCI [3-5]. However, stakes are high in ACS in high-risk groups to not intervene with PCI and adapt medical management safely. An expert panel published a study recently offering constructive criticism of the AUC and pointed out the deficiencies in AUC and the risk involved in adapting the AUC in high risk groups (Percutaneous coronary intervention uses in the United States: Defining Measures of Appropriateness by Arbab-Zadeh et al. . They argued that while minimizing overuse of PCI is important, the AUC that were developed do not assess properly the effectiveness of PCI in high risk subgroups such as DM-II, known as significant CAD. In their criticism, they highlighted a few facts and made recommendations for revisions to AUC :
• Relying on these tests for authorization for coronary angiography would be inappropriate.
• Provocative testing in high-risk symptomatic patients is risky.
• Minimizing overuse and underuse of PCI should be a national healthcare priority.
• The AUC do not assess effectiveness (PCI can be appropriate without improvement of symptoms).
• Scenario 12B (1- or 2-vessel disease, without proximal LAD, low-risk findings on noninvasive testing, 0 or 1 anti-angina medications (of CCS class I or II) should be changed to ‘uncertain.’
• The CTO-specific AUC categories should be removed.
The above concerns by experts highlight the unpredictability of CAD and the inadequacy of current noninvasive testing in assessing obstructive CAD (OCAD). This is more so in high-risk groups such as women and diabetics. Various types of testing modalities for coronary ischemia are recognized as sensitive but lack specificity with high false positivity. There is growing consensus that this lack of specificity results in a significant number of