Saha P, et al. - Researchers assessed the risk of adverse cardiovascular events related to lower-complexity adult congenital heart disease (ACHD) that conventional risk factors can’t account for. Among >500,000 British adults in the UK Biobank, they identified individuals with lower-complexity ACHD and those without for comparison using a multitiered classification algorithm. With retrospectively and prospectively gathered data from the UK Biobank, a maximum follow-up of 22 years was performed. A higher burden of adverse cardiovascular events was observed among subjects with lower-complexity ACHD vs general population, that was not accounted for by conventional cardiovascular risk factors. In this growing population of high-risk adults, closer surveillance is required.