Atrial Fibrillation: Obviating the Need for Anticoagulants With Percutaneous Closure of Left Atrial Appendage/ PLAATO & PROTECT-AF Trials

Left atrial appendage (LAA) occlusion is a potential alternative to warfarin in patients with atrial fibrillation who have contraindications to anticoagulation. Currently, there are two devices specifically designed for percutaneous LAA occlusion: the Percutaneous LAA Transcatheter Occlusion (PLAATO System, ev3 Inc., Plymouth, Minnesota) and the WATCHMAN LAA system (Atritech Inc., Plymouth, Minnesota). Despite early interesting and promising data from the PLAATO device, this device was withdrawn by the manufacturer in 2006. Early data on the WATCHMAN system were reported in 2007, and this device is the focus of the recently published PROTECT-AF (WATCHMAN Left Atrial Appendage System for Embolic Protection in Patients with Atrial Fibrillation) study. According to the results of the study, the efficacy of percutaneous closure of the LAA with this device was non-inferior to that of warfarin therapy, suggesting that closure of the LAA might provide an alternative strategy to chronic warfarin therapy for stroke prophylaxis in patients with non-valvular atrial fibrillation

In Vivo Aortic Valve Thermal Heterogeneity in Patients With Nonrheumatic Aortic Valve Stenosis The First In Vivo Experience in Humans

ObjectivesWe investigated in vivo in aortic valve stenosis (AVS) whether there is: 1) thermal heterogeneity within the valve leaflets; 2) temperature difference between the leaflets and the ascending aortic wall; and 3) a possible correlation between heat production, inflammation, and neoangiogenesis.BackgroundHistological studies have demonstrated a potential role of inflammation and neoangiogenesis in AVS.MethodsWe examined 96 leaflets scheduled for aortic valve replacement. Twenty-five patients had AVS, and 7 had aortic valve insufficiency (AVI). Temperature measurements were performed right before hypothermic cardioplegia. Temperature difference (ΔT) was assigned as the mean temperature of each leaflet minus the temperature of the aortic wall. Histological, immunohistological analysis, and vascular endothelial growth factor (VEGF) immunoreactivity was performed.ResultsSignificant thermal heterogeneity was recorded within the leaflets of AVS, compared with AVI (1.52 ± 1.35°C vs. 0.13 ± 0.11°C, p < 0.01). In AVS ΔT was greater in all leaflets compared with the AVI group (p < 0.01). Leaflets of AVS had increased inflammatory cell infiltration, calcium deposit, and anti-VEGF expression compared with AVI (p < 0.01).ConclusionsThermal heterogeneity is increased in AVS and correlates with inflammatory mononuclear cell infiltration, expression of pro-inflammatory cytokines and neoangiogenic factors