Integration of non-invasive functional assessments with anatomical risk stratification in complex coronary artery disease: The non-invasive functional SYNTAX score

Since the early days of coronary angiography, the extension and severity of coronary artery disease (CAD) have been used for risk stratification. The SYNTAX score objectively characterizes CAD in patients with multivessel disease. Furthermore, recalculating the SYNTAX score by the incorporation of the functional component coronary stenosis (i.e., FFR) increases the discrimination for the risk of adverse events. The calculation of the SYNTAX score derived from non-invasive modalities such as coronary computed tomography angiography (CTA) has emerged as a mean to obtain the SYNTAX score before invasive cardiac catheterization. Likewise, the computation of the non-invasive fractional flow reserve CT (FFRCT) allows for the calculation of the non-invasive functional SYNTAX score. Ultimately, the combination of anatomical and functional evaluations with clinical factors further refines the identification of patients at risk and provides a recommendation for the Heart Team regarding the treatment strategy (i.e., PCI or CABG) based on the predicted 4-year mortality. The purpose of this review is to describe the integration of a novel non-invasive functional coronary assessment with the angiographic risk score in patients with multivessel CAD.