Coronary artery calcium scoring
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Tarek Nafee, M.D. [2]
Overview
The presence of coronary artery calcification (CAC) indicates underlying CHD.[1] The CAC scan is a non-contrast CT scan used to visualize the extent of calcification in the coronary vessels.[2]
Coronary Artery Calcium Scoring
The Agatston score is a scoring system that uses images obtained from a non-contrast CT. It is determined by the number of calcific lesions, the area of each lesion and the peak HU of each lesion detected. The score for every calcific lesion is based on its density score and area (mm2).[3]
The density score is determined by the peak HU and is as follows:
- 1 = 130 - 199 HU
- 2 = 200 - 299 HU
- 3 = 300 - 399 HU
- 4 = >399 HU
If a lesion had a peak HU of 250 and an area of 4 mm2, it would receive a score of 8.
The CAC is the sum of the scores assigned to each calcific lesion.
The severity of CAC is as follows:[4]
| Coronary Artery Calcium Score | Calcification Grade |
|---|---|
| 0 | None |
| 0-10 | Minimum |
| 11-100 | Mild |
| 101-400 | Moderate |
| >400 | Severe |
Volume method
Role of CAC score in Clinical Practice
The presence of CAC indicates underlying CHD. While there is a strong correlation between CAC burden and coronary plaque area, CAC scans do not identify noncalcified plaques that are capable of erosion or rupture. Therefore, CAC is not a good predictor of luminal obstruction.[1]
Although CAC screening improves upon the current Framingham Risk Score, there is no prospective data that indicates that CAC screening results in a reduction of coronary events.[1]
Guidelines regarding the use of CAC have changed over the past few years. In 2010, the American College of Cardiology stated that the use of CAC is appropriate in asymptomatic, low risk individuals with a family history of CHD and in individuals with an intermediate risk of CHD (10%-20% 10 year risk of CHD).[5] However, this has changed in the 2013 guidelines. The latest recommendation by the ACC is that CAC can be used to guide risk based decision making if after quantitative risk assessment, a risk based decision is uncertain.[6]
Due to concerns related to cumulative radiation exposure, routine serial CAC scans are not currently recommended.[1]
Current Guidelines
| Guideline | Recommendation | ||
|---|---|---|---|
| Class | Level of Evidence | ||
| 2013 ACC/AHA Guideline on the Assessment of Cardiovascular Risk [6] | If after quantitative risk assessment, a risk-based decision is uncertain, one or more of the following tools may be used to aid in decision making: family history, hs-CRP, CAC score or ABI. | IIb | B |
| 2016 European Guidelines on Cardiovascular Disease Prevention In Clinical Practice [7] | CAC may be considered as a risk factor in CV risk assessment in patients with a calculated SCORE risk between 5% to 10%. | IIb | B |
| Recommendation | |||
| ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR
2010 Appropriate Use Criteria for Cardiac Computed Tomography [8] |
CAC would be appropriate in patients with a 10-20% 10-year risk of CHD. | Appropriate | |
| CAC would be appropriate in low risk patients (<10% 10-year risk of CHD) with a family history of premature CHD. | Appropriate | ||
| The usefulness of CAC is uncertain in patients with peripheral arterial disease or other coronary risk equivalents, or have a 10-year CHD risk greater than 20%, or who are 40 or older with diabetes. | Uncertain | ||
| CAC would be inappropriate in low risk patients (<10% 10-year risk of CHD). | Inappropriate | ||
References
- ↑ 1.0 1.1 1.2 1.3 Shah NR, Coulter SA (2012). "An evidence-based guide for coronary calcium scoring in asymptomatic patients without coronary heart disease". Tex Heart Inst J. 39 (2): 240–2. PMC 3384065. PMID 22740742.
- ↑ Hecht HS (2015). "Coronary artery calcium scanning: past, present, and future". JACC Cardiovasc Imaging. 8 (5): 579–96. doi:10.1016/j.jcmg.2015.02.006. PMID 25937196.
- ↑ Agatston AS, Janowitz WR, Hildner FJ, Zusmer NR, Viamonte M, Detrano R (1990). "Quantification of coronary artery calcium using ultrafast computed tomography". J Am Coll Cardiol. 15 (4): 827–32. PMID 2407762.
- ↑ van der Bijl N, Joemai RM, Geleijns J, Bax JJ, Schuijf JD, de Roos A; et al. (2010). "Assessment of Agatston coronary artery calcium score using contrast-enhanced CT coronary angiography". AJR Am J Roentgenol. 195 (6): 1299–305. doi:10.2214/AJR.09.3734. PMID 21098187.
- ↑ Greenland P, Alpert JS, Beller GA, Benjamin EJ, Budoff MJ, Fayad ZA; et al. (2010). "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. 56 (25): e50–103. doi:10.1016/j.jacc.2010.09.001. PMID 21144964.
- ↑ 6.0 6.1 Goff DC, Lloyd-Jones DM, Bennett G, Coady S, D'Agostino RB, Gibbons R; et al. (2014). "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". Circulation. 129 (25 Suppl 2): S49–73. doi:10.1161/01.cir.0000437741.48606.98. PMID 24222018.
- ↑ Piepoli MF, Hoes AW, Agewall S, Albus C, Brotons C, Catapano AL; et al. (2016). "2016 European Guidelines on cardiovascular disease prevention in clinical practice: The Sixth Joint Task Force of the European Society of Cardiology and Other Societies on Cardiovascular Disease Prevention in Clinical Practice (constituted by representatives of 10 societies and by invited experts)Developed with the special contribution of the European Association for Cardiovascular Prevention & Rehabilitation (EACPR)". Eur Heart J. 37 (29): 2315–81. doi:10.1093/eurheartj/ehw106. PMC 4986030. PMID 27222591.
- ↑ Taylor AJ, Cerqueira M, Hodgson JM, Mark D, Min J, O'Gara P; et al. (2010). "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 Cardiovasc Comput Tomogr. 4 (6): 407.e1–33. doi:10.1016/j.jcct.2010.11.001. PMID 21232696.