Discrepancy between computed tomography coronary angiography and selective coronary angiography in the pre-stenting assessment of coronary lesion length

We aimed to compare the lesion length measured on computed tomography coronary angiography (CT-CA) with the selective coronary angiography (SCA) lesion length measured on quantitative coronary angiography (QCA). Compared with SCA, CT-CA has the advantage of showing the lumen and the atherosclerotic plaque in the arterial wall. This prospective observational study involved 44 coronary lesions. Computed tomography coronary angiography was carried out with an electrocardiogram-gated 16-slice CT before percutaneous coronary intervention. A cardiologist and a radiologist measured CT lesion lengths in consensus, whereas an interventional cardiologist carried out QCA to obtain SCA lesion lengths independently. The median difference of (CT lesion length - SCA lesion length) was 9.84 mm (95%CI: 7.26, 13.34]). The median difference of (stent length - SCA lesion length) was 7.68 mm (95%CI: 6.29, 9.26]); the median difference of (stent length - CT length) was -2.63 mm (95%CI: -5.80, 0.05]). The mean ratio of stent length to SCA lesion length was 2.07 (95%CI: 1.83, 2.30]). The mean ratio of stent length to CT-CA lesion length was 0.97 (95%CI: 0.83, 1.11]). In the subgroup of drug-eluting stents (17 lesions), the median difference of (stent length - SCA lesion length) was 9.76 mm (95%CI: 6.59, 13.28]); the median difference of (stent length - CT length) was -5.2 mm (95%CI: -11, 0.5]). The mean ratio of stent length to CT-CA lesion length was 0.93 (95%CI: 0.68, 1.17]). Computed tomography lesion length was substantially longer than SCA lesion length measured by QCA. Routine practice of choosing stent length based on QCA may underestimate the actual length of target lesion. This may lead to incomplete coverage of the target lesion, particularly when drug-eluting stents are used.