Oxidative Stress in Structural Valve Deterioration: A Longitudinal Clinical Study.

The cause of structural valve deterioration (SVD) is unclear. Therefore, we investigated oxidative stress markers in sera from patients with bioprosthetic heart valves (BHVs) and their association with SVD. Blood samples were taken from SVD (Phase A) and BHV patients during the first 24 (Phase B1) and >48 months (Phase B2) after BHV implantation to assess total antioxidant capacity (TAC), malondialdehyde (MDA), and nitrotyrosine (NT). The results show that MDA levels increased significantly 1 month after surgery in all groups but were higher at 6 months only in incipient SVD patients. NT levels increased gradually for the first 24 months after implantation in the BHV group. Patients with transcatheter aortic valve implantation (TAVI) showed even higher levels of stress markers. After >48 months, MDA and NT continued to increase in BHV patients with a further elevation after 60-72 months; however, these levels were significantly lower in the incipient and established SVD groups. In conclusion, oxidative stress may play a significant role in SVD, increasing early after BHV implantation, especially in TAVI cases, and also after 48 months' follow-up, but decreasing when SVD develops. Oxidative stress potentially represents a target of therapeutic intervention and a biomarker of BHV dysfunction.

The role of antibody responses against glycans in bioprosthetic heart valve calcification and deterioration.

Bioprosthetic heart valves (BHVs) are commonly used to replace severely diseased heart valves but their susceptibility to structural valve degeneration (SVD) limits their use in young patients. We hypothesized that antibodies against immunogenic glycans present on BHVs, particularly antibodies against the xenoantigens galactose-α1,3-galactose (αGal) and N-glycolylneuraminic acid (Neu5Gc), could mediate their deterioration through calcification. We established a large longitudinal prospective international cohort of patients (n = 1668, 34 ± 43 months of follow-up (0.1-182); 4,998 blood samples) to investigate the hemodynamics and immune responses associated with BHVs up to 15 years after aortic valve replacement. Early signs of SVD appeared in <5% of BHV recipients within 2 years. The levels of both anti-αGal and anti-Neu5Gc IgGs significantly increased one month after BHV implantation. The levels of these IgGs declined thereafter but anti-αGal IgG levels declined significantly faster in control patients compared to BHV recipients. Neu5Gc, anti-Neu5Gc IgG and complement deposition were found in calcified BHVs at much higher levels than in calcified native aortic valves. Moreover, in mice, anti-Neu5Gc antibodies were unable to promote calcium deposition on subcutaneously implanted BHV tissue engineered to lack αGal and Neu5Gc antigens. These results indicate that BHVs manufactured using donor tissues deficient in αGal and Neu5Gc could be less prone to immune-mediated deterioration and have improved durability.

Twenty-Year Secular Trends in Infective Endocarditis in a Teaching Hospital.

BACKGROUND: The purpose of this study was to analyze the secular trends of infective endocarditis in a teaching hospital between January 1996 and December 2015. METHODS: We report on a single-center retrospective study of patients with left-side valve infective endocarditis. We performed an analysis of secular trends in the main epidemiological and etiological aspects, as well as clinical outcomes, in 5 successive 4-year periods (P1 to P5). RESULTS: In total, 595 episodes of infective endocarditis were included, of which 76% were community-acquired and 31.3% involved prosthetic valves. Among the cases, 70% occurred in men, and the mean age (SD) was 64.1 (14.3) years. A significant increase in older patients (age ≥70 years) between P1 (15.332%) and P5 (51.9%; P < .001) was observed. The rate of infective endocarditis on biological prostheses also increased in the prosthetic group, accounting for 30% in P1 and 67.3% in P5 (P < .001). By contrast, there were significant decreases in vascular and immunological phenomena over the study period, with decreases in the presence of moderate to severe valvular insufficiency (75.9% in P1 to 52.6% in P5; P < .001) and valvular surgery (43% in P1 vs 29.6% in P5; P = .006). Finally, overall mortality was 23.9%, and although it was highest in P1, it subsequently remained stable through P2 to P5 (38% in P1 to 20% in P5; P = .004). CONCLUSIONS: There has been a significant increase in infective endocarditis in older patients. The decrease in moderate to severe valve regurgitation at diagnosis could explain the stable mortality despite the increase in the mean age of patients over time.