Relation between age, arterial distensibility, and aortic dilatation in the Marfan syndrome

This study examined the relations between age, arterial distensibility, and systemic hemodynamics in patients with the Marfan syndrome. The study group included 170 patients referred to a specialist clinic, of whom 55 (age 26 ± 12 years) were diagnosed as having Marfan syndrome. The remaining 115 patients (age 25 ± 14 years) formed a control group. Each patient underwent echocardiographic examination, with measurement of ascending aorta diameter at end-diastole and end-systole, and aortic flow velocities. The elastic properties of the aorta were indexed by calculation of aortic distensibility, wall stiffness, and systemic pulse wave velocity. Mean end-diastolic aortic diameter in the Marfan group (38 ± 9 mm) was greater than that in the controls (26 ± 4 mm, p < 0.01). Resting heart rate and aortic flow velocities were similar in the 2 groups, but systemic arterial pulse pressure was greater in the Marfan group (50 ± 12 mm Hg) than in the controls (41 ± 8 mm Hg, p < 0.01). Aortic diameter increased with age in both groups, but at all ages the Marfan group exhibited greater aortic diameters (p < 0.05). Aortic distensibility was less in the Marfan group (2.6 ± 1.3 cm² · dynes^-1. 10^-6) than in the controls (6.2 ± 2.1 cm² · dynes^-1 · 10^-6, p < 0.01), and the aortic wall stiffness index was greater in the Marfan group (7.9 ± 3.4) than in the controls (2.8 ± 0.6, p < 0.01). Aortic wall stiffness increased with age and aortic diameter, but at all ages the Marfan group exhibited a stiffer aorta for a given diameter than did the controls. Systemic pulse wave velocity was greater in the Marfan group (621 ± 139 cm · s^-1) than in the controls (394 ± 62 cm · s^-1, p < 0.01). In patients with the Marfan syndrome, the aorta exhibits markedly abnormal elastic properties from an early age, including increased stiffness and increased systemic pulse wave velocities.