Abstract 5864: In Vivo Aortic Valve Thermal Heterogeneity In Patients With Non-rheumatic Aortic Valve Stenosis: First In Vivo Experience In Humans
Background: Histological studies have demonstrated a potential role of inflammation and neoangiogenesis in aortic valve stenosis (AVS). Inflammatory activation may generate heat. We investigated in vivo in patients with AVS whether there is:
thermal heterogeneity within the valve leaflets,
temperature difference between the leaflets and the ascending aortic wall and
a possible correlation between heat production, inflammation and neoangiogenesis.
Methods: We examined 96 leaflets from 32 patients scheduled for aortic valve replacement. Seventy-five leaflets were from 25 patients with AVS and 21 from 7 patients with aortic valve insufficiency (AVI) (control group). Temperature measurements were performed right before the hypothermic cardioplegia. Temperature difference (ΔT) was assigned as the mean temperature of each aortic leaflet minus the temperature of the aortic wall.
Results: Histological, immunohistological analysis for inflammatory cells and vascular endothelial growth factor (VEGF) immunoreactivity was performed. Significant thermal heterogeneity was recorded within the leaflets of AVS, compared AVI (1.52±1.35°C vs 0.13±0.11°C, p<0.01). In AVS ΔT was 1.09±1.16°C for the non-coronary (NC), 1.24±1.03°C for the right and 1.53±1.23°C, for the left leaflet. ΔT was lower in AVI (0.10±0.10°C for the NC, 0.02±0.19°C for the right and 0.05±0.19°C, for the left leaflet, p<0.01 for all comparisons). Leaflets of AVS had increased inflammatory cell infiltration, calcium deposit, and anti-VEGF expression compared to AVI (p<0.01).
Conclusions: Thermal heterogeneity is increased in AVS and correlates with inflammatory mononuclear cell infiltration, expression of pro-inflammatory cytokines and neoangiogenic factors. Future studies need to be performed to investigate possible prognostic and therapeutic implications.