Quantitative coronary CT angiography: absolute lumen sizing rather than %stenosis predicts hemodynamically relevant stenosis.

Abstract

ObjectiveTo identify the most accurate quantitative coronary stenosis parameter by CTA for prediction of functional significant coronary stenosis resulting in coronary revascularization.Methods160 consecutive patients were prospectively examined with CTA. Proximal coronary stenosis was quantified by minimal lumen area (MLA) and minimal lumen diameter (MLD), %area and %diameter stenosis. Lesion length (LL) was measured. The reference standard was invasive coronary angiography (ICA) (>70 % stenosis, FFR <0.8).Results210 coronary segments were included (59 % positive). MLA of ≤1.8 mm2 was identified as the optimal cut-off (c = 0.97, p < 0.001; 95 % CI 0.94–0.99) (sensitivity 90.9 %, specificity 89.3 %) for prediction of functional-relevant stenosis (for MLA >2.1 mm2 sensitivity was 100 %). The optimal cut-off for MLD was 1.2 mm (c = 0.92; p < 0.001; 95 % CI 0.88–95) (sensitivity 90.9, specificity 85.2) while %area and %diameter stenosis were less accurate (c = 0.89; 95 % CI 0.84–93, c = 0.87; 95 % CI 0.82–92, respectively, with thresholds at 73 % and 61 % stenosis). Accuracy for LL was c = 0.74 (95 % CI 0.67–81), and for LL/MLA and LL/MLD ratio c = 0.90 and c = 0.84.ConclusionsMLA ≤1.8 mm2 and MLD ≤1.2 mm are the most accurate cut-offs for prediction of haemodynamically significant stenosis by ICA, with a higher accuracy than relative % stenosis.Key Points• Quantitative coronary CT-angiography is accurate for prediction of functional relevant stenosis. • Absolute lumen area and diameter rather than %stenosis predict functional relevance. • Lumen area <1.8 mm 2 and diameter <1.2 mm are the most accurate cut-offs. • Quantitative parameters are helpful for decision-making in terms of patient management.