INFECTION AFTER PEDIATRIC HEART-TRANSPLANTATION - RESULTS OF A MULTIINSTITUTIONAL STUDY

Background: Detailed information regarding the spectrum and predictors of infection after heart transplantation in children is limited becau se of relatively small numbers of patients at any single institution. We therefore used combined data obtained from the Pediatric Heart Tran splant Study Group to gain additional information regarding infectious complications in the pediatric population. Methods: To determine the time-related risk of infection and death related to infection in a lar ge pediatric patient population, we analyzed data related to 332 pedia tric patients (undergoing heart transplantation between January 1, 199 3, and December 31, 1994) from 22 institutions in the Pediatric Heart Transplant Study Group. Results: Among the 332 total patients, 276 inf ections were identified in 136 patients. Of those patients with develo pment of infection, a single infection episode was reported in 54% of patients, 21% had two infections, and 25% had three or more infections . Of the 276 infections, 164 (60%) were bacterial, 51 (18%) were due t o cytomegalovirus, 35 (13%) were other viral (noncytomegalovirus) infe ctions, 19 (7%) were fungal, and 7 (2%) were protozoal. Bacterial infe ctions were more common in infants younger than 6 months of age at tim e of transplantation, comprising 73% of all infections as compared wit h 49% in patients older than 6 months of age. The incidence of bacteri al infection peaked during the first month after transplantation, with the actuarial likelihood of a bacterial infection among all patients reaching 25% at 2 months. The most common sites of bacterial infection were blood and lung (74% of bacterial infections). Cytomegalovirus ac counted for 59% of viral infections, with a peak hazard occurring at 2 months after transplantation. Among all infections, cytomegalovirus w as less common in infants younger than 6 months of age (8% of all infe ctions) than in older patients (25%). By multivariate analysis, risk f actors for early infection included younger recipient age (p = 0.05), mechanical ventilation at time of transplantation (p = 0.0002), positi ve donor cytomegalovirus serologic study result with negative recipien t result (p = 0.004), and longer donor ischemic time (p = 0.04). The o verall mortality rate from infection was 5%, with an actuarial freedom from death related to infection of 92% at 1 year after transplantatio n. The mortality rate was high in patients with fungal infections (52% ), yet was low for those with cytomegalovirus infection (6%). Infectio ns accounted for 27% of the overall mortality rate in infants younger than 6 months of age, compared with 16% for older patients. Conclusion s: Although most infections in pediatric heart transplant recipients a re successfully treated, infection remains an important cause of postt ransplantation morbidity and death, especially in infants. Bacterial i nfections predominate within the first month after transplantation, wh ereas the peak hazard for viral infections occurs approximately 2 mont hs after transplantation. Cytomegalovirus infections are common in the pediatric transplant population, but death related to cytomegalovirus is low.