Low birth weight or diagnosis, which is a higher risk?--A meta-analysis of observational studies

Published experience with surgical treatment of newborns with low birth weight and congenital heart disease is circumscribed to isolated single case reports and a limited number of case-series. To better assess the risks of early surgical treatment and its relationship to weight and diagnosis we performed a meta-analysis of observational studies, limited to those from which data on individual patients could be extrapolated. A search on the subject in peer-reviewed journals published between 1993 and 2004 limited the number of studies, according to our restrictive criteria, to six articles. Our own series of 37 patients was added to the body of data collected in the meta-analyses. Data on 356 individually identified patients was extracted from the articles. Median weight was 2.05 kg (range 1.1-2.5) and median gestational age was 34.2 weeks (range 26-42). Overall surgical survival was 83.9% but survival was higher when a full repair was done (86.1%). According to our analysis, diagnosis was the most significant predictor of mortality (p = 0.001). Other important predictors were the presence of a surgical complication (p = 0.01), palliative surgery (p = 0.03) and the need for reoperation during the same admission (p = 0.03). We concluded that similarly to larger newborns, diagnosis in this group of patients is the most important predictor of mortality. Independently of patient's weight a full anatomic and physiologic repair is justified in most cases.