Genetic and environmental effects on carotid flow velocities: An international twin study

Abstract

Introduction: Altered carotid blood flow velocities (CFV) have a complex background but the underlying genetic contribution is still unclear. We sought to evaluate the influence of genetics, shared and unshared environmental components on individual differences of CFV. Methods: 193 healthy twin pairs, 126 monozygotic (MZ) and 67 dizygotic (DZ) (mean age 53±14 years) recruited in Italy, in the United States and in Hungary underwent bilateral color-coded Doppler flow assessment of the common carotid artery (CCA) and of the internal carotid artery (ICA) in order to assess the peak systolic (PSV) and end diastolic (EDV) velocities. Means of bilateral CFV values were used in the analysis. Results: Age- and country-adjusted intra-class correlations were higher in monozygotic than in dizygotic pairs for mean PSV of the ICA indicating a heritability of 63%. Unique environmental factors contributed to 37% of ICA PSV. With regards to the mean PSV and EDV of the CCA, and EDV of the ICA, heritabi