A 52-Year-Old Man With Atherosclerosis
A 52-year-old executive was referred to our clinic for risk factor management after undergoing coronary computed tomography angiography (CTA) as part of an Executive Physical. He has no history of coronary artery disease and exercises regularly without experiencing anginal symptoms.
His family history is notable for a myocardial infarction (MI) in his father at the age of 52 years. He is a lifelong non-smoker. He does not take medications.
His blood pressure was 110/75. His exam was notable for being overweight with a BMI of 27, but was otherwise unremarkable.
His total cholesterol is 206 mg/dL, HDL-C is 46 mg/dL, triglycerides are 178 mg/dL, calculated LDL-C is 124 mg/dL, and non HDL-C is 160 mg/dL. His fasting glucose is 86 mg/dL. His Hgb A1c is 5.6%.
His 10-year risk based on the 2013 ACC/AHA pooled ASCVD risk estimator is 3.7%.
His coronary artery calcium (CAC) score is 120, which places him in the 87th percentile for his age, gender, and ethnicity.
His coronary CTA shows the following in the proximal LAD:
In addition to maximizing therapeutic lifestyle changes (exercise, weight loss), what is the next step in this patient’s management?
The correct answer is: B. Maximize risk factor modification by starting a low-dose aspirin and statin therapy.
Atherosclerosis is necessary for nearly all coronary events. The development of atherosclerosis is multifactorial. There is significant heterogeneity in the contribution of common traditional modifiable risk factors including apolipoprotein B (apoB)-containing lipoproteins, smoking, diabetes, hypertension, and sedentary lifestyle to atherogenesis.1 In participants from the Multi-Ethnic Study of Atherosclerosis (MESA) without atherosclerosis as measured by coronary artery calcium (CAC), even the presence of multiple modifiable risk factors was associated with low event rates (3.1%). In contrast, in those with elevated CAC and no modifiable risk factors, the event rates were significantly higher at nearly 11%.1
While risk estimators are improving in accuracy,2,3 the presence of subclinical atherosclerosis (primarily by CAC) has consistently been an additive predictor of coronary events in individuals and further discriminates between those at higher and lower risk for events.4-6 The case patient is at elevated risk because of the burden of subclinical atherosclerosis and, therefore, answer choice A is incorrect.
The recent 2013 ACC/AHA guidelines on cholesterol treatment take a risk-based approach to recommendations for statin therapy.7 The patient in this case has a low estimated 10-year risk at 3.7%. The current guidelines suggest a risk discussion in this case based on the patient's family history of premature coronary heart disease (CHD). Subclinical atherosclerosis imaging by CAC scanning can help with this discussion.8
Recently, eight-year follow-up from the Dallas Heart Study showed that among participants with a family history of MI, those without CAC experienced a significantly lower CHD event rate of 1.9% compared to 8.8% in those with any CAC.9 The case patient has a CAC score >100 that places him above the 75th percentile for his age, gender, and ethnicity. We would recommend moderate- or high-intensity statin therapy during a risk discussion based on an estimated 10-year event rate that exceeds 7.5%. Furthermore, recent data support the use of aspirin in those with CAC >100. Therefore, answer choice B is the correct answer.
Subclinical atherosclerosis imaging with CAC scanning has been endorsed by several committees to assist with risk assessment. The 2010 ACC/AHA risk assessment guidelines gave CAC scanning a IIA recommendation in those deemed to be at intermediate risk for CHD events.11 In the 2010 appropriate use criteria for cardiac CT endorsed by multiple societies, CAC scanning was deemed appropriate among low-risk asymptomatic patients with a family history of premature CHD in addition to those at intermediate risk.12 Most recently, the 2013 ACC/AHA risk assessment guidelines gave CAC scoring a IIB recommendation. Specifically, the committee suggests that if there is uncertainty about whether to start pharmacotherapy after risk estimation, then CAC scoring could be considered.2
An important consideration in this case is the use of CTA to identify subclinical atherosclerosis. While coronary CTA is a more specific and sensitive test for atherosclerosis, there is no evidence that CTA adds significantly to CAC scanning in an asymptomatic population. However, CTA may identify vulnerable features of plaque that are not picked up by CAC scanning, such as those present in the case example.13 Motoyama et al. identified high-risk features for acute coronary syndromes (ACS) in asymptomatic subjects on CTA including positive remodeling and low-attenuation plaque, in addition to spotty calcification in those presenting with ACS.14,15 A small preliminary study suggested a benefit of statin therapy on plaque volume and the amount of low-attenuation plaque.16 The role of CTA in asymptomatic, primary prevention patients is actively under investigation.17 The benefits of CTA should be weighed against exposure to contrast, expense, and the need to train readers. With rapidly advancing technology, CTAs can now be performed with the equivalent radiation exposure of two mammograms.18
Currently, the use of CTA is useful in appropriate symptomatic patients, particularly in chest pain protocols in the emergency department.19 Many of these patients have mild or moderate, non-obstructive atherosclerosis that is unlikely to be the cause of their presenting symptoms, but should be managed with aggressive preventive therapies. In symptomatic patients from the CONFIRM registry, there is an increased hazard of mortality in those with non-obstructive atherosclerosis on CTA compared to those without atherosclerosis on CTA.20
Some have advocated for stress testing in those with CAC scores > 400; however, the patient in this case does not meet this criteria.21,22 Therefore, answer choices C and D are incorrect as the patient is asymptomatic.
- Silverman MG, Blaha MJ, Krumholz HM, et al. Impact of coronary artery calcium on coronary heart disease events in individuals at the extremes of traditional risk factor burden: the Multi-Ethnic Study of Atherosclerosis. Eur Heart J. 2013 Dec 13 [Epub ahead of print].
- Goff DC, Jr., Lloyd-Jones DM, Bennett G, et al. 2013 ACC/AHA guideline on the assessment of cardiovascular risk: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol 2014;63:2935-59.
- Muntner P, Colantonio LD, Cushman M, et al. Validation of the atherosclerotic cardiovascular disease Pooled Cohort risk equations. JAMA 2014;311:1406-15.
- Polonsky TS, McClelland RL, Jorgensen NW, et al. Coronary artery calcium score and risk classification for coronary heart disease prediction. JAMA 2010;303:1610-6.
- Erbel R, Möhlenkamp S, Moebus S, et al. Coronary risk stratification, discrimination, and reclassification improvement based on quantification of subclinical coronary atherosclerosis: the Heinz Nixdorf Recall study. J Am Coll Cardiol 2010;56:1397-406.
- Yeboah J, McClelland RL, Polonsky TS, et al. Comparison of novel risk markers for improvement in cardiovascular risk assessment in intermediate-risk individuals. JAMA 2012;308:788-95.
- Stone NJ, Robinson J, Lichtenstein AH, et al. 2013 ACC/AHA guideline on the treatment of blood cholesterol to reduce atherosclerotic cardiovascular risk in adults: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol 2014;63:2889–934.
- Nasir K, Budoff MJ, Wong ND, et al. Family history of premature coronary heart disease and coronary artery calcification: Multi-Ethnic Study of Atherosclerosis (MESA). Circulation 2007;116:619-26.
- Paixao AR, Berry JD, Neeland IJ, et al. Coronary artery calcification and family history of myocardial infarction in the Dallas Heart Study. JACC Cardiovasc Imaging. 2014 June [Epub ahead of print].
- Miedema MD, Duprez DA, Misialek JR, et al. Use of coronary artery calcium testing to guide aspirin utilization for primary prevention: estimates from the multi-ethnic study of atherosclerosis. Circ Cardiovasc Qual Outcomes 2014;7:453-60.
- Greenland P, Alpert JS, Beller GA, et al. 2010 ACCF/AHA guideline for assessment of cardiovascular risk in asymptomatic adults: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol 2010;56:e50-103.
- Taylor AJ, Cerqueira M, Hodgson JM, et al. ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 appropriate use criteria for cardiac computed tomography. a report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the North American Society for Cardiovascular Imaging, the Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance. J Am Coll Cardiol 2010;56:1864-94.
- Voros S, Rinehart S, Qian Z, et al. Coronary atherosclerosis imaging by coronary CT angiography: current status, correlation with intravascular interrogation and meta-analysis. JACC Cardiovasc Imaging 2011;4:537-48.
- Motoyama S, Sarai M, Harigaya H, et al. Computed tomographic angiography characteristics of atherosclerotic plaques subsequently resulting in acute coronary syndrome. J Am Coll Cardiol 2009;54:49-57.
- Motoyama S, Kondo T, Sarai M et al. Multislice computed tomographic characteristics of coronary lesions in acute coronary syndromes. J Am Coll Cardiol 2007;50:319-26.
- Inoue K, Motoyama S, Sarai M, et al. Serial coronary CT angiography-verified changes in plaque characteristics as an end point: evaluation of effect of statin intervention. JACC Cardiovasc Imaging 2010;3:691-8.
- U.S. National Institutes of Health.Detection of Subclinical Atherosclerosis in Asymptomatic Individuals (Decide CTA). (ClinicalTrials.gov website). 2009-2014. Available at: http://clinicaltrials.gov/ct2/show/NCT00862056?term=DECIDE-CTA. Accessed June 22, 2014.
- Achenbach S, Marwan M, Ropers, D et al. Coronary computed tomography angiography with a consistent dose below 1 mSv using prospectively electrocardiogram-triggered high-pitch spiral acquisition. Eur Heart J 2010;31:340-6.
- Hoffmann U, Truong QA, Schoenfeld DA, et al. Coronary CT angiography versus standard evaluation in acute chest pain. N Engl J Med 2012;367:299-308.
- Min JK, Dunning A, Lin FY, et al. Age- and sex-related differences in all-cause mortality risk based on coronary computed tomography angiography findings results from the International Multicenter CONFIRM (Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter Registry) of 23,854 patients without known coronary artery disease. J Am Coll Cardiol 2011;58:849-60.
- Hendel RC, Berman DS, Di Carli MF, et al. ACCF/ASNC/ACR/AHA/ASE/SCCT/SCMR/SNM 2009 appropriate use criteria for cardiac radionuclide imaging: a report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the American Society of Nuclear Cardiology, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the Society of Cardiovascular Computed Tomography, the Society for Cardiovascular Magnetic Resonance, and the Society of Nuclear Medicine. J Am Coll Cardiol 2009;53:2201-29.
- Berman DS, Hachamovitch R, Shaw LJ, et al. Roles of nuclear cardiology, cardiac computed tomography, and cardiac magnetic resonance: Noninvasive risk stratification and a conceptual framework for the selection of noninvasive imaging tests in patients with known or suspected coronary artery disease. J Nucl Med 2006;47:1107-18.