Abstract 562: Evidence of Protozoan Biofilm Communities in Atheromatous Debris

Abstract

Background: Evidence that vascular inflammation is an important mechanism involved in all stages of atherogenesis continues to accumulate. We hypothesize that common complex microbial involvement may be present in atheromatous debris removed from treated lesions. We evaluated this debris with metagenomic analysis. Methods: After informed consent, fifteen cases of vascular aspirate or explanted embolic filters were examined. Thirteen cases were in patients undergoing carotid stenting (3 MoMa, 10 embolic filters). One case was in a saphenous vein graft intervention (aspirate and filter) and one case was after SFA orbital atherectomy (aspirate and filter). Fluorescence microscopy, bacterial and protozoan metagenomic analysis using the RIDI™ Next Generation Sequencing (NGS) analysis system, and specific protozoan multiplex PCR probes were used to assess the presence and composition of biofilm populations. Results: Bacteria were not detected in peripheral blood; however, 4 of 12 filters and 2 of 5 atheroma debris samples had identified bacterial populations (2 patients had atheroma debris and filter evaluated). Evidence of protozoan populations was obtained in 4 of 15 peripheral blood samples, 11 of 12 filters and 4 of 5 atheroma debris samples. Microscopy illustrated a complex composition of biofilm communities in blood, devices, and atheroma debris samples. The identified bacterial taxa in atheroma debris suggest a diverse and novel population composition. Biofilm dwelling bacteria, while present in several atheroma or filter samples, were not detectable in peripheral blood and were not universally present in atheroma or filter. Taxonomic comparisons of sequenced protozoa are consistent with a diverse array of organisms similar to poorly characterized environmental protozoa. Conclusion: Of 15 patients, 6 patients had evidence of bacteria and 13 had evidence of protozoa in debris and 14 exhibited evidence of complex biofilm communities. This data suggests that biofilm forming protozoa may play a key role in arterial vascular disease.