A new optical coherence tomography-based calcium scoring system to predict stent underexpansion

AIMS: This was a retrospective study to develop and validate an optical coherence tomography (OCT)-based calcium scoring system to predict stent underexpansion. METHODS AND RESULTS: A calcium score was developed using 128 patients with pre- and post-stent OCT (test cohort) and then validated in an external cohort of 133 patients. In the test cohort, a multivariable model showed that the independent predictors of stent expansion were maximum calcium angle per 180° (regression coefficient: -7.43; p180°, 1 point for maximum thickness >0.5 mm, and 1 point for length >5 mm. In the validation cohort, the lesions with calcium score of 0 to 3 had excellent stent expansion, whereas the lesions with a score of 4 had poor stent expansion (96% versus 78%, p180°, maximum thickness >0.5 mm, and length >5 mm may be at risk of stent underexpansion.