Prevalence and significance of two major inherited thrombophilias in infective endocarditis

The pathogenesis of infective endocarditis (IE) involves activation of the haemostasis system at the site of endocardial defects. Whether prothrombotic conditions are associated with IE by enhancing early vegetation formation is unknown. In this study, we assess the prevalence and clinical significance of two major conditions associated with thrombophilia in patients with IE. Mutations G20210A of the prothrombin (PTH) gene and G1691A of factor V (FV Leiden) gene were studied by means of allele-specific polymerase chain reaction in 203 IE patients, 175 valvular heart disease (VHD) patients and 200 blood donors (BD). IE patients show higher cumulative frequencies of mutated alleles of PTH and FV Leiden [6.4 vs 3.25 %; OR 2.03 (95 % CI 0.97-3.66); p = 0.047] compared to BD, but not VHD. Device-related IE is enriched with FV Leiden, and prosthetic valve IE with PTH mutations (allele frequency 8.3 vs 2.2 % in native valve IE; p = 0.021). Vegetation size and embolic complications are not influenced by the examined thrombophilias. A trend for a higher mortality was observed in IE patients with any of the two thrombophilias studied. Our data do not support a role for factor V Leiden and G20210A prothrombin gene mutations in the susceptibility to IE. Whether any of these genetic polymorphisms play a role in a specific subtype of IE needs to be re-examined in larger studies.