Coronary Calcification on a Lung Health Check: What should be done?

Introduction

The Targeted Lung Health Check (TLHC) program was designed to detect lung cancer in the early stages and improve outcomes. What we have seen though, is an additional, massive incidental finding burden. This provides an opportunity to identify individuals at high cardiovascular risk by assessment of coronary artery calcification (CAC) on low-dose CT (LDCT) scans. Analysing data from 3 UK based lung screening cohorts (West London Pilot, Manchester Lung Screening Study, and Lung Screen Uptake Trial - LSUT), show a strong correlation between CAC severity and major adverse cardiovascular event (MACE) risk. Patients with moderate-to-severe CAC have a 5.4 to 7 fold increased risk of myocardial infarction within 10 years. These data are comparable to event rates seen in formal calcium scoring and underscore the role of CAC from TLHC in guiding primary prevention strategies.

Pathophysiology of CAC

• CAC results from atherosclerotic plaque calcification, serving as a marker for coronary artery disease (CAD) burden.

• Smokers and ex-smokers (the primary LHC target population) exhibit higher CAC prevalence due to chronic inflammation, oxidative stress, and endothelial dysfunction.

• Data from NLST, NELSON, and European screening trials confirm a 3-fold increased cardiovascular mortality risk in individuals with any CAC.

UK LHC Cohorts: CAC Prevalence and Risk Stratification

UK LHCs use visual grading of CAC into mild, moderate, and severe categories:

CAC Severity	Description	UK Cohort Prevalence	Associated MI Risk Increase
None	No visible CAC	34-40%	Baseline risk
Mild	<1/3 of artery calcified	43% (Croydon)	2× MI risk
Moderate	1/3–2/3 of artery calcified	23% (West London)	5.4× MI risk
Severe	>2/3 of artery calcified	23% (Manchester)	7× MI risk

• 43% of participants in West London LHC had mild CAC, while 23% had moderate/severe calcification.

• In the LSUT study, 29% of participants with mild CAC had QRISK2 scores >10%, indicating statin eligibility, yet only 36% of those eligible were on lipid-lowering therapy.

Cardiovascular Risk and Outcomes in CAC-Positive Patients

Mild CAC: Elevated Risk but Modest Treatment Uptake

• 2× MI risk increase compared to CAC-negative individuals.

• LSUT data indicate 57% of patients with mild CAC remain untreated despite meeting statin eligibility criteria.

Moderate/Severe CAC: High-Risk Group

• 5.4- to 7-fold MI risk increase in UK LHC data.

• NELSON trial found a 10.24-fold all-cause mortality risk for CAC >400.

• 68% of moderate/severe CAC patients in West London were prescribed statins after TLHC screening.

Long-Term Mortality Risk

• The Danish Lung Cancer Screening Trial (DLCST) showed a 5-year survival rate of 92% for CAC >400, compared to 98% for CAC-negative individuals.

• NELSON trial analysis demonstrated a 7.77-fold increased risk of MACE in severe CAC patients, even after controlling for smoking pack-years and metabolic syndrome.

NHS Primary Care Guidance: CAC Management in TLHC

TLHC Coronary Calcification Primary Care Algorithm:

1. No Known CHD/CVD:

• Lipid profile and QRISK3 assessment.

• Mild CAC → Consider atorvastatin 20mg if QRISK3>10%.

• Moderate CAC → Start atorvastatin 40mg/80mg.

• Severe CAC → Escalate therapy, consider ezetimibe.

2. Known CHD/CVD:

• Ensure high-dose statin therapy (atorvastatin 80mg).

• If non-HDL >2.5 mmol/L or LDL >1.8 mmol/L, add ezetimibe or PCSK9 inhibitors.

3. Symptomatic Patients:

• If cardiac-sounding chest pain, refer to RACPC or General Cardiology.

4. Referral Pathways for Primary Care:

• CVD Risk and Lipid Clinic A&G for statin/lipid queries.

• General Cardiology A&G for symptomatic patients.

Barriers to Implementation in Primary Care

• Only 57% of TLHC participants with CAC attend GP follow-ups.

• 22.6% undergo a management change post-screening.

• Patient perception of CAC as an “incidental” finding leads to low adherence to treatment.

Cost-Effectiveness of CAC-Based Intervention

• Incremental cost of CAC reporting: £5.69 per participant.

• MILD trial models show CAC-guided statin therapy prevents 12.4 MACE per 1,000 screened individuals over 5 years.

• Estimated cost per QALY gained: £8,200, below UK NHS thresholds.

Demographic Disparities in CAC Prevalence

• Age & Smoking Duration:

• CAC prevalence increases with age:

• 60–65 years: 48%

• 66–70 years: 63%

• 71–75 years: 79%

• Pack-years >40 = 3.2× risk of severe CAC.

• Gender Differences:

• 62% of males in UK LHCs have CAC vs. 38% of females (Manchester cohort).

• Hormonal/metabolic protection may explain lower female prevalence.

Limitations & Future Directions

1. Lack of Standardized Reporting – 71.6% inter-radiologist agreement in CAC grading.

2. Underpowered Long-Term Outcome Data – Yorkshire Lung Screening Trial aims to address this with 10-year follow-up.

3. Need for Higher GP Referral Adherence – Strategies to improve post-screening cardiovascular management are essential.

Conclusion

Why TLHC Coronary Calcification Matters for UK Primary Care

• 23–29% of TLHC participants exhibit clinically significant CAC, highlighting an opportunity for early cardiovascular intervention.

• 5.4–7× MI risk increase in moderate/severe CAC patients justifies aggressive primary prevention.

• TLHC provides a scalable model for embedding cardiovascular risk stratification into lung cancer screening.

“Detecting and managing cardiovascular risk is one of the ways TLHC saves lives” – RM Partners Programme Report.

Actionable Takeaways for Primary Care

• GPs should view CAC as a major cardiovascular red flag, not just an incidental finding.

• Routine lipid and QRISK3 assessment in CAC-positive LHC participants should be mandatory.

• Better integration of TLHC reports into primary care workflows is needed to prevent undertreatment of the CV risk represented by the incidental finding

By embedding CAC management into LHCs, the NHS has an unprecedented opportunity to tackle both lung cancer and cardiovascular disease, improving outcomes for high-risk smokers and ex-smokers.