What is Coronary Artery Disease (CAD)?
Coronary artery disease or coronary heart disease are terms which signify the accumulation of atherosclerotic (cholesterol-rich) plaques in the coronary arteries. A heart attack characteristically results from progressive build-up followed by sudden rupture of an atherosclerotic plaque, with resultant blockage of coronary blood flow.
Some individuals may have warning-sign symptoms in the lead-up to a first heart attack, most notably chest pain or chest heaviness on exertion, disproportionate shortness of breath with exercise, and palpitations or sweatiness in conjunction with chest heaviness. If present, these symptoms warrant urgent investigation. In many cases, however, there are no obvious symptoms present prior to a first heart attack. Coronary screening tests can provide valuable insights for those who are at elevated risk of coronary events. At-risk individuals include those with diabetes mellitus (two-fold increased risk of cardiovascular disease), high blood pressure, high cholesterol levels, cigarette smoking history, family history of cardiovascular disease, obesity, and/or chronic kidney disease.1
Commonly available screening or diagnostic tests for CAD largely fall into two categories:
Functional tests that detect cardiac abnormalities in response to stress
Anatomical tests that detect coronary plaques through direct visualization.
The benefits and limitations of commonly available tests are outlined below. Of note, blood tests such as troponin levels and resting electrocardiography (ECG) are not designed to detect CAD outside of the context of an acute heart attack and therefore are not reliable screening tests.
Coronary Artery Testing Modalities
Functional Tests
1. Graded Exercise Stress Test (GXT)
Description: Exercise to a target heart rate on a treadmill while monitoring ECG for changes that indicate a positive result.
Main Benefits:
Non-invasive with no radiation.
Provides insight into functional capacity and cardiovascular risk.
Main Limitations:
Lower sensitivity (68%) and specificity (77%).
Not suitable for those unable to exercise, reach target heart rate, or with certain ECG abnormalities.
2. Stress Echocardiogram (Exercise or Chemical)
Description: Evaluates heart wall motion during stress induced by exercise or medication.
Main Benefits:
Non-invasive, no radiation.
Useful when GXT is inconclusive or used alongside GXT.
Main Limitations:
Less sensitive than nuclear imaging; may miss mild disease.
Harder to interpret in obese individuals or those with emphysema.
3. Nuclear Medicine Myocardial Perfusion Imaging
Description: Combines stress testing with imaging to identify areas of reduced blood flow in the heart.
Main Benefits:
High sensitivity.
Effective in evaluating known CAD or inconclusive stress tests.
Main Limitations:
Radiation exposure.
May miss mild to moderate coronary lesions.
Possible false negatives in global ischemia or multivessel disease.
Anatomical Tests
1. CT Coronary Artery Calcium Score (CACS)
Description: Measures calcium buildup in coronary plaques; useful for assessing long-term risk.
Main Benefits:
Lower radiation than CCTA.
Ideal for asymptomatic or intermediate-risk individuals; aids cholesterol treatment decisions.
Main Limitations:
Does not detect non-calcified (higher risk) plaques.
Possible false positives in elderly with high calcification but no significant blockage.
2. CT Coronary Angiography (CCTA)
Description: Detailed CT scan of coronary arteries using contrast dye.
Main Benefits:
Very high sensitivity (99%) and specificity (89%).
Identifies both calcified and non-calcified plaques.
Main Limitations:
Involves radiation and iodinated contrast dye.
Limited accuracy in patients with stents, arrhythmias, or heavy calcification.
3. Conventional Coronary Angiogram
Description: Invasive procedure using catheterization and continuous X-ray to visualize coronary arteries.
Main Benefits:
Gold standard for diagnosing coronary artery disease.
Enables treatment interventions like stenting during the procedure.
Main Limitations:
Invasive with potential complications.
Continuous radiation exposure.
Almira Medical's Approach
In the long-term prevention of cardiovascular mortality, CAD screening can serve as a helpful adjunct to effective lifestyle changes and management of modifiable risk factors such as diabetes, hypertension, and high cholesterol. At Almira Medical we offer an annual, combined screening approach for coronary disease with graded exercise stress ECG (GXT) immediately followed by exercise stress echocardiogram. We prefer these screening modalities especially for asymptomatic individuals as they are non-invasive, can be performed safely and simultaneously in an office setting, and can be performed as often as needed without any concern for cumulative radiation exposure. Furthermore, exercise stress testing provides additional valuable information on an individual's functional capacity, as measured by metabolic equivalents (METs), which correlates strongly with an individual's cardiovascular mortality risk.5 If there are abnormalities or equivocal results based on initial screening tests, further testing such as with CT Coronary Angiography, nuclear imaging, or conventional (invasive) coronary angiography may be pursued on a case-by-case basis. When no concerns are identified, clearance for intensive aerobic activity can typically be granted, providing peace of mind. For those with negative stress tests we offer subsequent VO2 Max testing to further characterize an individual's aerobic capacity and to inform an individualized exercise prescription.
To learn more about Almira Medical's comprehensive testing and preventative care programs, and to take the next steps to maximizing your potential longevity, contact us to today.
References
Emerging Risk Factors Collaboration. Diabetes mellitus, fasting blood glucose concentration, and risk of vascular disease: a collaborative meta-analysis of 102 prospective studies. The lancet. 2010 Jun 26;375(9733):2215-22.
Arena R, Myers J, Williams MA, Gulati M, Kligfield P, Balady GJ, Collins E, Fletcher G. Assessment of functional capacity in clinical and research settings: a scientific statement from the American Heart Association Committee on Exercise, Rehabilitation, and Prevention of the Council on Clinical Cardiology and the Council on Cardiovascular Nursing. Circulation. 2007 Jul 17;116(3):329-43.
Mairesse GH, Marwick TH, Arnese M, Vanoverschelde JL, Cornel JH, Detry JM, Melin JA, Fioretti PM. Improved identification of coronary artery disease in patients with left bundle branch block by use of dobutamine stress echocardiography and comparison with myocardial perfusion tomography. The American journal of cardiology. 1995 Aug 15;76(5):321-5.
Chow BJ, Small G, Yam Y, Chen L, McPherson R, Achenbach S, Al-Mallah M, Berman DS, Budoff MJ, Cademartiri F, Callister TQ. Prognostic and therapeutic implications of statin and aspirin therapy in individuals with nonobstructive coronary artery disease: results from the CONFIRM (COronary CT Angiography EvaluatioN For Clinical Outcomes: An InteRnational Multicenter registry) registry. Arteriosclerosis, thrombosis, and vascular biology. 2015 Apr;35(4):981-9.
RJ G. ACC/AHA 2002 guideline update for exercise testing: summary article. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Update the 1997 Exercise Testing Guidelines). J Am Coll Cardiol. 2002;40:1531-40.