Microvascular Responses to Donor Specific HLA Antibodies in Heart Transplantation. Sidestream Dark Field Imaging Results
Purpose: The presence of Donor Specific Antibodies (DSA) is recognized for its ability to trigger vascular damage and neo-intimal remodeling through various mechanisms. Our study focused on examining the impact of HLA antibodies on the microcirculation using sidestream dark field (SDF) imaging with GlycoCheck analysis in Heart Transplant recipients.
Methods: The health status of sublingual microvasculature (MV) was assessed using a sidestream darkfield camera linked to the GlycoCheck software. This system captured videos illustrating the real-time movement of red blood cells (RBCs) within the microvessels and computed five functional parameters: (a) perfused boundary region (PBR), (b) capillary density;(c)blood flow and density; (d) recruitment capacity; and (e) a global MV_HealthScore (MVHS). Two groups were defined according to the presence of absence of DSA at the time of measurement.
Results: 90 heart transplant recipients were included. The median age was 53 years (IQR 43-60),39% were females and 24% were Black. No significant differences were found in baseline characteristics between the groups except for diabetes that was more prevalent in the non-DSA group (43% vs 16%; p=0.01;Fig1A). Time from transplant to microvascular assessment was longer in the DSA group (5 yrs vs 1 yr; p=0.005). The DSA group showed a higher prevalence of a previous history of antibody-mediated rejection, with rates of 43% compared to 16% in the non-DSA group (p=0.01). The use of prednisone and mycophenolate treatments was more frequent in the non-DSA group (p=0.049). When evaluating the microvascular health, patients with DSA exhibited greater total microvascular density (56 vs. 45; p=0.04) and higher flow (78 vs. 53; p=0.02). Even after conducting a sub-analysis that excluded patients with diabetes as a potential confounder, the results remained consistent
Conclusion: Preliminary data suggest that the presence of DSA had no adverse effect on microvascular health in heart transplant recipients.