Compliance and Pulse Wave Velocity Assessed by MRI Detect Early Aortic Impairment in Young Patients With Mutation of the Smooth Muscle Myosin Heavy Chain

Purpose: To evaluate aortic elasticity with MRI on young asymptomatic individuals with mutation of the smooth muscle myosin heavy chain in whom aortic enlargement is not present. Materials and Methods: Aortic compliance, aortic distensibility, and pulse wave velocity (PWV) were semiautomatically measured from MRI in 8 asymptomatic subjects having a mutation of the MYH11 gene (M+) and 21 nonmutated relatives (M-) of similar age, sex, and blood pressure characteristics. Results: Despite a similar aortic diameter in both groups. the aortic compliance and distensibility were significantly lower in M+ subjects compared with M- (0.84 +/- 0.33 versus 2.03 +/- 0.54 mm(2)/mmHg. 1.18 +/- 0.62 10(-3) versus 5.11 +/- 1.58 10(-3) mmHg(-1), respectively), and PWV was significantly higher (5.35 +/- 1.53 versus 3.60 +/- 0.64 m. s(-1)). A threshold aortic compliance value of 1.3 mm(2)/mmHg separated the two groups. The receiver operating characteristics curve analysis indicated an optimal threshold of 2.9 10(-3) mmHg(-1) for aortic distensibility (sensitivity: 87.5%, specificity: 90%), and of 4.4 m.s(-1) for PWV (sensitivity: 75%, specificity: 100%). Conclusion: Young asymptomatic adults with MYH11 mutation have an aortic compliance impairment which is not detectable by the sole measurement of the aortic size. Aortic compliance measurement might be part of routine examination in patients suspected of inherited aortic disease even with a normal aortic diameter.