Physicians' Academy for Cardiovascular Education

Substantial risk variation among vascular patients: risk stratification can be refined

Kaasenbrood L, et al., Circulation 2016

Distribution of Estimated 10-Year Risk of Recurrent Vascular Events and Residual Risk in a Secondary Prevention Population

Kaasenbrood L, Boekholdt SM, van der Graaf Y, et al.
Circulation 2016; published online ahead of print


The risk of recurrent events is generally considered to be similar in most patients with a clinical manifestation of vascular disease. However, it is unclear whether these patients are all at high vascular risk, in particular if they are treated according to current guidelines.
In this study, the variation in 10-year risk of recurrent vascular events was assessed in patients with CAD, CVD, PAD or aortic aneurysm, using the SMART risk score [1], which was validated in three external populations: 9447 CAD patients from the usual-dose statin arm of the TNT and IDEAL trials, 2366 patients with CVD from the placebo arm of the SPARCL and 6623 patients with PAD from both arms of the CAPRIE trial [2-5]. Moreover, the achieved risk reduction based on guideline-recommended risk factor targets was evaluated, as well as the residual risk.

Main results

The estimated 10-year risk of recurrent vascular events and mortality in patients with vascular disease varied from <5% to >50% (median estimated risk 17%; IQR: 11%-28%).
  • 18% of patients had a 10-year risk of <10%,
  • 22% of patients had a 10-year risk of >30%,
  • CAD patients had the lowest risks (median 14%; IQR: 10%-20%),
  • patients with poly-vascular disease had the highest risks (median 35%; IQR: 23%-54%).
External validation of the SMART risk score in TNT, IDEAL, SPARCL and CAPRIE:
  • Systematic overestimation of risk was seen among patients with an estimated 5-year risk >25% corresponding with an estimated 10-year risk of more than 40%.
  • Underestimation of risk was seen among CAD patients with a 5-year risk <20% (10-year risk less than 35%).
The overall median reducible risk was 5% (IQR: 2%-11%). This additional reducible risk was:
  • highest in patients with aortic aneurysms (16%; IQR: 9%-22%)
  • lowest in patients with CAD (3%; IQR: 1%-6%).
The estimated residual 10-year risk of recurrent vascular events varied substantially:
  • 47% of patients had a <10% risk,
  • 9% of patients had a >30% risk despite guideline-recommended risk factors targets
  • patients with poly-vascular disease had the highest residual risk (median 22%; IQR: 14%-36%)
  • patients with PAD had the lowest residual risk (median 8%; IQR: 5%-12%).


There is a substantial variation in the estimated 10-year risk of recurrent vascular events in patients with vascular disease, ranging between <10% and >30%. Achieving guideline-recommended risk factor targets could reduce the 10-year risk to less than 10% in half of the patients, however the residual risk showed marked variation, up to >30%.
These findings support the hypothesis that not all patients with vascular disease are at equally high risk of recurrent vascular events, and these patients may benefit from improved risk stratification. The SMART risk score showed reasonable performance in external validation cohorts, especially in those with up to 40% estimated 10-year risk.  
Find this article online at Circulation


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5. Pedersen TR, Faergeman O, Kastelein JJ, et al., Incremental Decrease in End Points Through Aggressive Lipid Lowering Study G. High-dose atorvastatin vs usual-dose simvastatin for secondary prevention after myocardial infarction: the IDEAL study: a randomized controlled trial. JAMA. 2005;294:2437-45.