Coronary artery calcium score: old faithful delivers again
In the previous issue of the Netherlands Heart Journal, Rijlaarsdam-Hermsen et al. describe the prognostic value of the coronary artery calcium (CAC) score in patients with suspected stable coronary artery disease [1]. In their study, the researchers correlated clinical outcome with the CAC scores of 644 stable chest pain patients who underwent CAC scoring as part of their diagnostic work-up. Their results show that increasing CAC scores are associated with an increased risk of mortality and adverse cardiac events. A large body of literature has accumulated since the introduction of CAC scoring in the late 1980s [2]. Large, multicentre studies have established the strong prognostic value of CAC scoring in asymptomatic individuals [3, 4]. Absence of CAC, in particular, correlates with a very favourable outcome. In a meta-analysis including more than 70,000 study participants, absence of CAC was correlated with an event rate of less than 0.5% during a follow-up of 4 years [5]. This ‘power of zero’ was also encountered in a symptomatic population, albeit with a slightly higher incidence of cardiovascular events (i.e. 1.8%). Given the excellent prognosis, the additional value of further diagnostic testing of symptomatic patients in the absence of CAC can be debated, especially those with a low pre-test probability and longstanding complaints that correspond to a steady plaque build-up with calcification [6]. Once CAC is present, however, the story becomes more complicated with regard to how to apply the CAC results in clinical