07.01 Outward Hypertrophic Remodeling and Increased Carotid Artery Wall Stiffness in Patients with Ruptured Intracranial Aneurysms

Abstract

Because an underlying arteriopathy might contribute to the development and rupture of intracranial aneurysms (IAs), we assessed the elastic properties of proximal conduit arteries in 27 patients with antecedent of ruptured IAs (delay: 4.8±0.6 years) and 27 control subjects. Arterial pressure, diameter, intima-media thickness (IMT), circumferential wall stress (CWS) and elastic modulus were determined in the common carotid arteries using applanation tonometry and echotracking. Moreover, carotid augmentation index (AIx) and carotid-to-femoral pulse wave velocity (PWV) were assessed.

Compared to controls, patients with IA exhibit higher carotid systolic (108±2 vs. 122±3 mmHg), diastolic (73±1 vs. 81 ±1 mmHg) and pulse pressures (35±1 vs. 41 ±2 mmHg), an increased IMT (0.55±0.01 vs. 0.64±0.01 mm, all P<0.01) without difference in diameter. IMT was correlated with pulse pressure in controls (r=0.539, P<0.001) but not in patients (r=0.152, P = 0.2). Despite a similar CWS between groups, patients display an increased elastic modulus (0.21±0.02 vs. 0.37±0.03 kPa.10³, P<0.001). These increased IMT and modulus were still observed in patients matched with controls for carotid arterial pressures (n = 17 in each group). Furthermore, patients with IAs have higher PWV (7.8±0.2vs. 8.3±0.2 m.s⁻¹, P<0.05) which contributes to the increase in arterial wave reflections (AIx: 15.8±2.1 vs. 21.1±1.6%, P<0.05) and thus in systolic and pulse pressures.

This study demonstrates that patients with IAs display a particular carotid artery phenotype with a partly pressure-independent outward hypertrophic remodeling and altered elastic properties which might contribute together with the fatiguing effect of increased pulsatile stress on the arterial wall, to the pathogenesis of IAs.