Abstract 12003: Bioprosthetic Valves Have a Higher Longevity in Blood Group a Recipients
BACKGROUND: Pigs share with humans some of the antigens present on cardiac valves. Two such antigens are the major xenogenic Ag, “αGal” which mimics the human B antigen of ABO blood group system and the minor Ag, pig A antigen of AH blood group which is similar to that of human AH antigen. Despite chemical reticulation, the α-Gal is still expressed on the bioprosthesis and elicits an immunological response upon implantation. The role of AH on porcine heart valves is unknown. We hypothesize that these antigens may modify the immunogenicity of the bioprosthesis and also its longevity. ABO distribution may vary between patients with low (<6 years) and high (≥15 years) bioprosthetic longevity.
METHODS: Single-centre registry study (Paris, France) including all porcine bioprostheses (mostly Carpentier-Edwards 2nd/3rd generation heart valves) replaced between 1987-1998; and for the period 1998-2014 all bioprostheses with longevity ≥13 years (follow-up ≤27 yrs). Predictive factors for bioprosthesis longevity, i.e. number, site of implantation and age were collected. Blood group and other variables were entered into an ordinal logistic regression analysis model predicting valve longevity, categorized as low (<6 yrs), medium (6-14.9 yrs), and high (≥15 yrs).
RESULTS: Longevity and ABO blood group were obtained for 548 explanted bioprostheses. Mean longevity was 10.2 yrs+/-3.9 [0-28]. It was low in 11.3% patients, medium in 77.6%, and high in 11.1%. Mean longevity of group A recipients was significantly higher than for other blood groups (p=0.009). Using multivariate analysis, group A predicted a higher longevity category (OR 2.24, p=0.001) as did the number of valves replaced, single vs multiple (OR 2.36, p=0.001); aortic position vs other (OR 1.21, p=0.40); and age <60 years vs older (OR 3.33, p<0.001).
CONCLUSION: Patients of group A but not B have a higher longevity of their bioprostheses. Since only a fraction of pigs expresses the A antigen, its effect is probably underestimated due to the low probability of group A recipient to have randomly received a valve of the corresponding phenotype. Future graft-host phenotyping and matching may give rise to a new generation of long-lasting bioprosthesis for implantation in humans, especially for the younger population.
Author Disclosures: O. Schussler: None. N. Lila: None. T.V. Pernerger: None. P. Mootoosamy: None. M. Ruel: Research Grant; Modest; Medtronic. Honoraria; Modest; Medtronic. A. François: None. A. Kalangos: None. A. Carpentier: None.
- © 2014 by American Heart Association, Inc.