Risk assessment beyond traditional risk factors

• Coronary Artery Calcium Score

  AI search for risk with CAC over 1000

  This is an excellent, clinically relevant question. For a cardiologist, a Coronary Artery Calcium (CAC) score 1≥1000 (Agatston units) places a patient in a very high-risk category, often considered equivalent to a secondary prevention patient.2

  The data for the annual acute ischemic coronary event rate comes primarily from large, long-term, multi-ethnic cohort studies, such as the Multi-Ethnic Study of Atherosclerosis (MESA) and the CAC Consortium databases.

  Annualized Acute Ischemic Coronary Event Rate for CAC ≥1000

  Based on the MESA data and other large registry analyses of asymptomatic primary prevention individuals with a CAC score ≥1000:

  Event Rate Metric	Approximate Annualized Rate	Context/Reference
  3-Point MACE Rate	~3.4 events per 100 person-years	MESA: This includes non-fatal Myocardial Infarction (MI), non-fatal stroke, and cardiovascular (CV) death.
  Hard CHD Events Rate	~2.0–2.8 events per 100 person-years	Derived from MESA: This typically includes MI, resuscitated cardiac arrest, and Coronary Heart Disease (CHD) death.
  All CHD Events Rate	~7.6 per 1000 person-years	A separate analysis showed an annual CHD mortality rate of 5.1 per 1000 person-years in this group.

  Note: 3.4 events per 100 person-years translates to a 3.4% annual risk of a major adverse cardiac event.

  Key Clinical Implications for CAC ≥1000

  1. Secondary Prevention Equivalence: The most critical finding is that a CAC score of 3≥1000 in a primary prevention patient is associated with an annual 3-point MACE rate (~3.4%) that is similar to or higher than the event rates observed in stable, treated secondary prevention populations (e.g., those with known CAD or prior MI).4 This risk is substantially higher than the ≤1% annual risk typically seen with a CAC =0.
  2. No Plateau of Risk: The risk does not plateau at this high level; the risk continues to increase linearly as the CAC score climbs above 51000 (e.g., 61500, 72000).8

  3. Treatment Thresholds: Because of this high risk, a CAC score 9≥1000 is considered a powerful risk-enhancing factor that generally warrants the most aggressive preventive therapies, consistent with the management of a very high-risk patient.10 This includes:
  • High-intensity statin therapy.11
  • Strong consideration for Aspirin (in the absence of contraindications).
  • Potential consideration for non-statin therapies (e.g., ezetimibe, PCSK9 inhibitors) to achieve very low LDL-C goals, in line with secondary prevention guidelines.12
  4. Risk Factors: A CAC 13≥1000 identifies a cohort with a high prevalence of diffuse, multi-vessel disease and often other high-risk features like diabetes and severe left main coronary artery calcification, all of which further compound the risk.14

   

  From

  Gemini

   

   

  2021

  Very High Coronary Artery Calcium (≥1000) and Association With Cardiovascular Disease Events, Non–Cardiovascular Disease Outcomes, and Mortality: Results From MESA

  https://doi.org/10.1161/CIRCULATIONAHA.120.050545

   

  JACC Imaging 2021- risk with CAC greater than 1000