Multislice CT for assessing in-stent dimensions after left main coronary artery stenting: a comparison with three dimensional intravascular ultrasound.

OBJECTIVE To evaluate the agreement between multislice CT (MSCT) and intravascular ultrasound (IVUS) to assess the in-stent lumen diameters and lumen areas of left main coronary artery (LMCA) stents. DESIGN Prospective, observational single centre study. SETTING A single tertiary referral centre. PATIENTS Consecutive patients with LMCA stenting excluding patients with atrial fibrillation and chronic renal failure. INTERVENTIONS MSCT and IVUS imaging at 9-12 months follow-up were performed for all patients. MAIN OUTCOME MEASURES Agreement between MSCT and IVUS minimum luminal area (MLA) and minimum luminal diameter (MLD). A receiver operating characteristic (ROC) curve was plotted to find the MSCT cut-off point to diagnose binary restenosis equivalent to 6 mm(2) by IVUS. RESULTS 52 patients were analysed. Passing-Bablok regression analysis obtained a β coefficient of 0.786 (0.586 to 1.071) for MLA and 1.250 (0.936 to 1.667) for MLD, ruling out proportional bias. The α coefficient was -3.588 (-8.686 to -0.178) for MLA and -1.713 (-3.583 to -0.257) for MLD, indicating an underestimation trend of MSCT. The ROC curve identified an MLA ≤ 4.7 mm(2) as the best threshold to assess in-stent restenosis by MSCT. CONCLUSIONS Agreement between MSCT and IVUS to assess in-stent MLA and MLD for LMCA stenting is good. An MLA of 4.7 mm(2) by MSCT is the best threshold to assess binary restenosis. MSCT imaging can be considered in selected patients to assess LMCA in-stent restenosis.