Temporal Evolution of Neointimal Proliferation After Implantation of Two Types of Drug-eluting Stents with Biodegradable Polymers in a Porcine Model: Qualitative Assessment by Sequential Optical Coherence Tomography

ABSTRACTBackgroundBased on the hypothesis that the neointima found in drug-eluting stents (DES) with biodegradable polymers at 28days is not a definitive neointima and that optical coherence tomography (OCT) is an effective method for sequential neointimal evaluation, we aim, in this experimental study, to compare OCT findings at 28 and 90days, in two different DES with biodegradable polymers: the sirolimus-eluting stent (Inspiron®, Scitech) and the biolimus A9-eluting stent (Biomatrix®, Biosensors International).MethodsOverall, 6 non-atherosclerotic pigs were submitted to the implantation of 6 Inspiron® stents and 6 Biomatrix® stents. Each pig received both stent types, one in each coronary artery (left anterior descending artery and circumflex artery) and after 28 and 90 days qualitative in-stent OCT analyses were performed at 1-millimeter intervals.ResultsQualitative assessment was performed in-stent pairing millimeter by millimeter. Heterogeneous neointimal tissue was evidenced in 39% at 28days and in 0% at 90days, the presence of intraluminal tissue in 18% at 28days and in 0% at 90days, luminal irregularity in 62% at 28days and in 2% at 90days (P < 0.005). There was no difference between groups regarding the quality of the neointima over time (P > 0.05).ConclusionsThe OCT findings corroborate the hypothesis that the neointima found in DES with biode gradable polymers at 28days is not a definitive neointima. The most significant experimental evidence is the change in the neointimal characteristics observed at sequential OCT