Comparison of Atheroma Burden Changes Using Conventional vs. End-Diastolic Intravascular Ultrasound Segmentation - Post Hoc Analysis of the PACMAN-AMI Study.

Background This study compared changes in percentage atheroma volume (PAV) using an end-diastolic (ED) intravascular ultrasound (IVUS) segmentation approach vs. the conventional 1-mm interval analysis in serial IVUS data from the PACMAN-AMI trial.Methods And Results IVUS data from the PACMAN-AMI study were analyzed by 2 core laboratories: one with 1-mm segmentation and the other with an ED-based approach. The same arterial segments were assessed at baseline and at the 52-week follow-up in patients receiving alirocumab or placebo. Changes in segment length, lumen, vessel, total atheroma volume (TAV), and PAV between baseline and follow-up were compared between methods. Biomarkers associated with atherosclerotic progression were measured and correlated with TAV and PAV changes. In all, 387 segments were analyzed. Agreement between conventional and ED volumetric analysis was excellent (intraclass coefficient >0.891, P<0.001). TAV and PAV were larger in both groups in the ED analysis than with the conventional approach; however, changes between treatment arms were similar for the conventional and ED analyses (TAV: 14.34 vs. 14.64 mm3, respectively P=0.823; PAV: 1.29% vs. 1.25%, respectively P=0.911). Biomarker correlations with TAV and PAV changes did not differ between approaches.Conclusions ED- and 1-mm-based analyses demonstrated comparable treatment effects of alirocumab on plaque regression in PACMAN-AMI. These findings support the use of the less time-consuming 1-mm segmentation method in serial IVUS studies.