Abstract 14097: Cardiovascular Event Prediction and Risk Reclassification by Coronary, Aortic, and Valvular Calcification in the Framingham Heart Study
Background: We determined whether vascular and valvular calcification predict incident major coronary heart disease (CHD), cardiovascular disease (CVD), and all cause mortality independent of Framingham Risk Factors (FRF) in the community-based Framingham Heart Study.
Methods: Coronary artery calcium (CAC), thoracic aortic calcium (TAC), abdominal aortic calcium (AAC), and mitral or aortic valve calcium (MVC and AVC, respectively) were measured by cardiac computed tomography in 3454 participants free of known CVD in the Offspring and 3rd Generation cohorts of the Framingham Heart Study. All participants were of white ethnicity and were followed for incident major CHD, major CVD, and all cause mortality through a median of 5 years. We tested association of CAC, TAC, AAC, MVC and AVC with endpoints using multivariate Cox proportional hazards models, and analyzed improvement in discriminatory value beyond FRF via the c-statistic and net reclassification index (NRI).
Results: Event rates during follow up were 1.4%, 2.2% and 1.9% for major CHD, CVD and all cause mortality; respectively. Most calcifications were significantly related to incident major CHD and CVD events independent of FRF but not all cause mortality (Table). CAC significantly improved discriminatory value (c-statistic) beyond FRF for CHD (0.80 vs. 0.84, p<0.05) but not for CVD (0.81 vs. 0.82, p=0.15). Risk prediction for CHD improved in models containing continuous CAC (NRI: 25%, 95% CI: 9%-42%) and categorical CAC (NRI: 28%, 95% CI: 12%-44%). The addition of CAC to FRF accurately reclassified 158 participants to lower risk (observed event rate: 1.3%) and 223 to higher risk (observed event rate: 6.7%).
Conclusions: Even after considering traditional Framingham risk factors or other calcifications CAC significantly improves discrimination of asymptomatic participants according to their risk for major CHD and moreover, accurately reclassifies them to higher or lower risk.
- © 2013 by American Heart Association, Inc.