TRANSMISSION OF HEPATITIS-B VIRUS AMONG HEART-TRANSPLANT RECIPIENTS DURING ENDOMYOCARDIAL BIOPSY PROCEDURES

Background: The unexpected conversion to HBsAg seropositivity of three cardiac allograft recipients prompted us to conduct a multidisciplina ry study to identify the source, transmission mode, and extent of the hepatitis B virus (HBV) infection among the 256 cardiac allograft reci pients of our hospital. Methods: All recipients were retrospectively s creened for serum markers of HBV infection. A selected genomic region defining subtypes of the viruses involved was amplified and sequenced. An epidemiologic case-control study for possible risk factors was con ducted to identify the mode of transmission. Results: Eighteen additio nal HBV-infected patients were identified, none of whom had shown symp toms of HBV infection. The involvement of one virus (subtype ayw 3) wa s shown in 20 of the 21 HBV-infected patients. This virus is found in less than 10% of HBV-infected individuals in The Netherlands. The demo nstration of a common source of infection, combined with results of th e epidemiologic study, identified posttransplantation endomyocardial b iopsy procedures as the most likely mode of transmission. However, we also found evidence of secondary virus transmission by cardiac cathete rization procedures to nonallograft recipients. Conclusions: The immun osuppressive therapy practiced in these patients to prevent allograft rejection may have not only facilitated virus transmission by causing high levels of viremia but also left the spreading of HBV undetected b y causing a subclinical course of the infection. These findings stress the necessity of strict hygienic precautions during intravascular dia gnostic procedures and indicate that vaccination against and routine m onitoring for certain bloodborne infections in cardiac allograft recip ients should be considered.