Optical coherence tomography follow-up 18 months after titanium-nitride-oxidecoated versus everolimus-eluting stent implantation in patients with acute coronary syndrome

Background: Inadequate neointimal coverage of stent struts is associated with late stent thrombosis. Purpose: To demonstrate the extent of neointimal coverage and strut malapposition in titanium-nitride-oxide-coated bioactive stents (BAS) versus everolimus-eluting stents (EES) by optical coherence tomography (OCT) performed at 18-month follow-up. Material and Methods: In the BASE-ACS trial, 827 patients presenting with acute coronary syndrome were randomized to receive either BAS or EES. Forty patients (20 BAS, 20 EES) underwent OCT at 18-month follow-up for evaluation of stent strut coverage, malapposition, and neointimal hyperplasia (NIH). Primary endpoint was binary stent strut coverage (ratio of covered struts to all analyzed struts multiplied by 100). Co-primary endpoint was the percentage of malapposed struts. Results: We analyzed 3465 struts in 330 cross-sections of BAS and 3327 struts in 316 cross-sections of EES. Binary stent strut coverage, based on strut-level analysis, was higher with BAS versus EES (99.5% versus 94.2%, respectively; P< 0.001), the strut-level percentage of malapposed struts was lower with BAS (0.6% versus 2.5%, respectively; P< 0.001). Yet, the mean NIH thickness was greater with BAS (237 +/- 125 versus 108 +/- 62 mu m, respectively; P< 0.001). Conclusion: In the current post-hoc analysis with OCT performed at 18 months, binary strut coverage, based on strutlevel analysis, was higher with BAS versus EES; strut-level malapposed struts were fewer with BAS; yet, BAS induced thicker NIH.