The Safety of Continuing Therapeutic Anticoagulation During Inferior Vena Cava Filter Retrieval: A 6-Year Retrospective Review from a Tertiary Centre.

PURPOSE: Assess the safety of inferior vena cava (IVC) filter retrieval in patients taking anticoagulation, compared to a non-anticoagulated cohort. MATERIALS AND METHODS: Single-centre retrospective analysis of patients who underwent IVC filter retrieval between January 2012 and February 2018. Information about patient demographics, anticoagulation, tilt, major and minor complications was collected. Major complications were defined as: IVC injury from the filter retrieval, retained fragment of filter, filter fracture and filter embolisation. Minor complications were defined as: neck haematoma and puncture site infection. RESULTS: Total of 357 patients (age 18-95, Male: 231) underwent IVC filter retrieval, comprising of Cook Celect Platinum, Cook Celect, and ALN-branded filters. Of these 182 patients were on anticoagulation and 175 patients were not on anticoagulation, based on the indication for the filter (thrombosis or prophylaxis) and at the discretion of the referring unit who were managing the anticoagulation. IVC filter retrieval was technically successful in 349 patients. Five major complications (1.4% of retrievals) were recorded and no minor complications (0% of retrievals). In the anticoagulation cohort, there were two major complications (1.1% of retrievals) both related to IVC injury. In the non-anticoagulated cohort, there were three major complications (1.7% of retrievals) relating to filter embolisation, IVC injury, and filter fracture. CONCLUSIONS: IVC filter retrieval is a safe procedure with a low complication rate. Being on anticoagulation does not increase the risk of a major complication or change the management of major complication compared with a non-anticoagulated cohort. IVC filter retrieval is safe to perform in patients currently taking prophylactic or therapeutic anticoagulation based on our cohort. LEVEL OF EVIDENCE: Level 3, retrospective cohort study.

CD90 Identifies Adventitial Mesenchymal Progenitor Cells in Adult Human Medium- and Large-Sized Arteries.

Mesenchymal stem cells (MSCs) reportedly exist in a vascular niche occupying the outer adventitial layer. However, these cells have not been well characterized in vivo in medium- and large-sized arteries in humans, and their potential pathological role is unknown. To address this, healthy and diseased arterial tissues were obtained as surplus surgical specimens and freshly processed. We identified that CD90 marks a rare adventitial population that co-expresses MSC markers including PDGFRα, CD44, CD73, and CD105. However, unlike CD90, these additional markers were widely expressed by other cells. Human adventitial CD90+ cells fulfilled standard MSC criteria, including plastic adherence, spindle morphology, passage ability, colony formation, and differentiation into adipocytes, osteoblasts, and chondrocytes. Phenotypic and transcriptomic profiling, as well as adoptive transfer experiments, revealed a potential role in vascular disease pathogenesis, with the transcriptomic disease signature of these cells being represented in an aortic regulatory gene network that is operative in atherosclerosis.