Stent Underexpansion Prediction Is Improved by Intravascular Ultrasound‐Based Distance‐Averaged Calcium Angles
Jia‐Jie Wang, Hang Liu, Yian Yao, Minyu Wu, Zi Ye, Hungchen Lin, Chengxing Liu, Fei Chen, Yan Lai, Xuebo LiuABSTRACT
Background
Calcified coronary lesion, assessed by intravascular ultrasound (IVUS)‐based maximum calcium angle, is an important predictor for stent underexpansion.
Aims
We aimed to determine whether the mean of all calcium angles measured within a specified distance from the maximum calcium site (distance‐averaged) using IVUS was associated with stent underexpansion.
Methods
Patients undergoing IVUS‐guided percutaneous coronary intervention (PCI) with drug‐eluting stent implantation between 2016 and 2022 in a single tertiary center were retrospectively analyzed. Pre‐PCI IVUS was used to assess the angles of calcified plaque every 1 mm; a total of 11 calcium angles were measured within 5 mm of the maximum calcium site. The endpoint was percent stent expansion, and stent underexpansion was defined as percent stent expansion < 70%.
Results
In the analysis of 87 stent underexpansions that occurred among 292 patients, distance‐averaged calcium angles were significantly associated with stent underexpansion. Discrimination increased when using distance‐averaged calcium angles instead of maximum calcium angle, with the area under the receiver operating characteristic curve (AUC) ranging from 0.75 (95% CI, 0.69−0.82) for 10 mm‐averaged calcium angles to 0.77 (95% CI, 0.72−0.83) for 2 mm‐averaged calcium angles ( p < 0.05). Compared to 2 mm‐averaged calcium angles, increasing measuring distance did not result in significant improvement in AUC.
Conclusion
Distance‐averaged calcium angles were associated with stent underexpansion. Compared with maximum calcium angle, distance‐averaged calcium angles improved the prediction of stent underexpansion. Among these, 2 mm‐averaged calcium angles may be a simpler, equally accurate approach to predicting stent underexpansion.