Impact of ABO Blood Group on Survival after Isolated Xenograft Aortic Valve Replacement

Objectives: Bioprosthetic heart valves of porcine or bovine origin are used for the majority of surgical aortic valve replacements (AVRs). While the advantages of xenografts compared with mechanical valves are known, information about the possible influence of blood type on long-term outcomes is lacking. The purpose of this study was to investigate long-term outcomes after bioprosthetic AVR with a particular focus on patient blood type.

Methods: A total of 6,205 consecutive patients who underwent isolated AVR between October 1994 and December 2017 from our high-volume center were included. Demographic, pre-, and perioperative data, as well as survival were analyzed with the focus on blood group characteristics as a possible influencing factor. Our mean follow-up was 9.0 ± 6.4 years.

Results: After data preprocessing, a total of 4,274 cases (1,521 porcine valves, 2,753 bovine valves, and 23 valve types) were included. Mean age was 69.7 ± 9.8 years, 56.6% male, 27% diabetes mellitus, 25.5% smoker, 14.1% peripheral vascular disease, and mean EF 57.8 ± 13.3% (no difference between blood groups). Kaplan–Meier survival analysis showed that survival was higher with blood groups O and A, followed by blood groups AB and B. Significant differences regarding survival were documented for blood groups O and A when compared with blood group B (O vs. B, p = 0.027; A vs. B, p = 0.023; O vs. A, p = 0.944; O vs. AB, p = 0.834; A vs. AB, p = 0.821; and B vs. AB, p = 0.224). Survival for patients with isolated mechanical AVR (n = 1,480) did not differ in subject to the different blood groups. Results for survival after xenograft AVR can be summarized as follows: O = A > AB > B. Cox regression showed that blood group B (p = 0.015, hazard ratio = 5.870) is an independent risk factor for survival after xenograft AVR. Rhesus factor positivity did not influence survival after biological aortic valve implantation (p = 0.995).

Conclusion: The present study demonstrated that ABO blood group influenced survival after isolated AVR of bioprostheses. Patients with blood group B had a higher mortality rate in long-term follow-up.