CT calcium scoring could be added to government-funded ‘Heart Health Checks’ to improve the targeting of statin treatment for primary prevention of cardiovascular disease, cardiologists say.
A Victorian study has found that the current Australian absolute cardiovascular disease risk (ACVDR ) calculator is less sensitive than international risk tools, with a higher statin treatment threshold (5-year risk of 10%) that excludes many patients with both family histories of early onset coronary artery disease (CAD) and subclinical atherosclerosis.
And while all cardiovascular risk tools are moderately sensitive for identifying people with coronary artery calcium, the Australian calculator was among the least sensitive, according to researchers led by Professor Thomas Marwick, Director of the Baker Heart and Disease Institute, Melbourne.
The findings come from a coronary artery calcium screening study of 1059 middle aged Australians (aged 40-70) without known CAD but with a family history of early onset CAD. The participants had 5‐year absolute risk of cardiovascular disease of 2–15% according to the Australian guidelines.
Almost half (45%) had non‐zero coronary artery calcium scores (median 5‐year ACVDR , 4.8%, with median coronary artery calcium score, 41.7, while the 55% with zero calcium scores had a median 5‐year ACVDR of 3.2%.
The study found that 77% of the 151 participants with high calcium scores (100 or more) warranting lipid-lowering treatment were deemed to be at low cardiovascular risk by Australian guidelines. Conversely, 19% of 75 participants at intermediate risk had zero calcium scores.
The researchers also noted that the ACVDR calculator – based on the now superseded Framingham model – was inferior to PCE, SCORE, and CUORE models with respect to identifying people with non‐zero calcium scores (AUC 0.674 vs 0.711 for the pooled cohort model.
Professor Marwick and colleagues said the findings showed that coronary artery calcium scores could be useful for identifying patients at intermediate risk, and used to change decisions about statin treatment in 40% of this patient group.
They said the data supported a recent CSANZ position statement that calcium scores are most helpful in patients at intermediate 10-year risk (10–20%).
“We propose a 5-year ACVDR risk of 5% as a suitable threshold for coronary artery calcium scoring for patients with family histories of early onset CAD,” they wrote in the MJA.
“By enhancing the heart health checks, we can better stratify their risk and proactively put in place preventive treatment where needed,” said Professor Marwick.
“As we are seeing with US guidelines, CCS could be used as a decision aid to consider statin therapy in intermediate risk patients, and to avoid treatment in those with zero CCS”.
“Because the prediction and management of coronary risk (rather than other events) is the main driver of clinical decision making in those with a family history of early onset CAD, calcium scoring may help personalise the application of the ACVDR calculator to this large and heterogenous group of patients.