Elastic aortic properties in patients with X syndrome

Introduction: Elastic properties of the aorta represent an important determinant of left ventricular function and coronary blood flow but there are few data about aortic stiffness in patients with X syndrome.

Aim: To investigate the elastic aortic proprieties (aortic stiffness and distensibility) and arterial wall motion velocities as measured by tissue Doppler imaging (TDI) in patients with cardiac X syndrome.

Materials and methods: Fifteen patients with X syndrome (typical chest pain and angiographically normal coronary arteries associated with a positive exercise test) were enrolled in the study. The control group consisted of 15 healthy patients. The aortic elastic indexes, namely distensibility (cm(2) dyne(-1)) and stiffness index (β index) were calculated from M-mode echocardiographically-derived thoracic aortic diameters using accepted formulae, and TDI parameters were measured on the wall of the ascending aorta 3 cm above the aortic valve. Anterior wall aortic expansion velocity (S), early (E) and late (A) diastolic retraction velocity and peak systolic strain were determined.

Results: Aortic elastic proprieties were more impaired in the syndrome X group than in the control group. Aortic distensibility was significantly lower in the syndrome X group (3.2 ± 1.3 vs. 7.95 ± 4 cm(2) dyne(-1), p<0.001), while stiffness index was higher (7.3 ± 2.1 vs. 4.1 ± 1.6, p<0.001) than in the control group. Peak systolic (S) and diastolic waves (E and A waves) of the aortic wall TDI were similar in patients and controls (S wave: 5.7 ± 1.6 cm/s vs. 5.8 ± 1.6 cm/s, E wave: -4.8 ± 2.0 vs. -4.1 ± 2.0 cm/s; A wave: -4.32 ± 2.1 vs. -4.76 ± 1.8 cm/s) while tissue strain of the aortic wall was lower in patients with X syndrome than controls (-12.80 ± 7% vs. -22.3 ± 5.9%, p<0.00001).

Conclusion: Deterioration in aortic elasticity properties in patients with cardiac syndrome X suggests that this disease may be a more generalised disturbance of the vasculature.