P7 The impact of coronary calcification on diagnostic performance of workstation CT derived fractional flow reserve - a multicentre experience

Abstract

Abstract Background On-site workstation based computed tomography derived fractional flow reserve (CT-FFR) is an emerging method to assess the vessel specific ischaemia in coronary artery disease (CAD). The impact of coronary calcification on its diagnostic performance is unknown. Purpose To evaluate the impact of coronary calcification on the diagnostic performance of reduced-order CT-FFR at detecting vessel specific ischaemia. Methods This is a retrospective pooled analysis of 141 patients with suspected CAD enrolled from 3 global centres who underwent CT-coronary angiography (CTA), onsite CT-FFR and invasive FFR. Coronary calcification was assessed by Agatston score (AS). The diagnostic performance of CT-FFR (≤0.8) and CTA (≥50%) in evaluation of vessel specific ischaemia (FFR ≤ 0.8) was assessed across AS quartiles (Q1-4). A comparison of diagnostic performance of the low to mid AS (Q1 to Q3) versus high AS (Q4) was performed. Results Mean age and median AS was 65.8 ± 9.9 and 327.3 (interquartile range = 78.5 – 798.1). Diagnostic accuracy, sensitivity and specificity of CT-FFR for low-mid AS (0-798) and high AS (799-4019) were 77.4% vs 82.9%; 78.9% vs 94.7%; 68.8% vs 76.5% respectively with no statistical difference between the two groups. The AUC for ischaemia of CT-FFR in low to mid AS was comparable with AUC in the high AS (0.76 [95% CI: 0.66-0.86] vs 0.84 [0.69-0.99]; P = 0.397). The AUC for ischemia for CT-FFR in both low to mid AS and high AS was significantly higher than for CTA (0.76 [0.66-0.86] vs 0.57 [0.50-0.64]; P = 0.003 and 0.84 [0.69-0.99] vs 0.48 [0.38-0.57]; P < 0.001 respectively). Conclusion On-site workstation CT-FFR demonstrated consistently high diagnostic performance in patients with high AS. Its diagnostic performance was superior when compared with significant stenosis assessment on CTA across all spectrum of Agatston scores.