Long-term outcome and medical radiation exposure in patients hospitalized for cardiovascular disease

Background: Lowradiation doses fromdiagnostic and therapeutic procedures may increase cancer incidence after decades in cardiac patients. The aim of the studywas to evaluate the long-termoutcome and the prognostic effect of radiological exposure. Methods: A retrospective cohort study examined 16,311 Italian cardiac patients without cancer consecutively hospitalized between 1970 and 2009 and followed-up for a median of 10 years. Cumulative estimated effective dose was calculated for the imaging procedures. Main causes of death and primary cancer onset were the end points and their relation with radiation exposure was analyzed by Cox model. Results: Over the years, there was an increasing trend of cancer, a decreasing trend of cardiovascular,with stability of other-causes death. Cumulative estimated effective radiation dosewas higher in patientswho died for cancer (20±19 mSv) compared to cardiovascular (17±17, P b 0.001) and other-causes deaths (15±17, p b 0.001). The cumulative estimated effective dose adjusted HRwas 1.004 (95% CI 1.000-1.009, p=0.045) for cancer death and 1.008 (95% CI 1.005-1.011, p b 0.001) for (fatal and non-fatal) cancer onset. Radiation effective dose was not predictive of cardiovascular mortality (HR=0.991), nor it was of other types of deaths (HR=0.995). Smoking was a predictor for cardiovascular mortality, but it was not of other types of deaths. Conclusions: Non-cardiovascular causes of death are responsible for almost half of later deaths in cardiac patients. The radiological exposure from medical imaging procedures is predictive of cancer risk and cancer death.