Augmentation index and central aortic blood pressure in patients with abdominal aortic aneurysms

Abstract

Abdominal aortic aneurysm (AAA) is a life-threatening disease as rupture of the aneurysm is associated with high mortality. The likelihood that an AAA will rupture is particularly influenced by the diameter of the aneurysm and the rate of expansion; the reasons for fast expansion are largely unknown. Applanation tonometry (APT) can predict outcome in certain cardiovascular diseases by measuring arterial stiffness (augmentation index, AIx) and central aortic blood pressure (CABP). We tested the hypothesis that AIx and CABP would be higher in patients with fast-progressing AAA. We performed APT and peripheral blood pressure measurements in 114 patients with AAA (11 women) with a mean ± SD age of 67.4±6.1 years. Annual AAA progression rate was determined by ultrasound. Patients were grouped into fast progressors (progression ≥2 mm/year) and slow progressors (progression <2 mm/year). Mean follow-up time after inclusion into the AAA surveillance programme was 22.1 ± 16.3 months. AIx was similar in fast progressors (27.3 ± 13.0%) and slow progressors (26.5 ± 12.6%) (P = 0.73). Fast progressors had a significantly higher CABP during systole (116.0 ± 16.0 mmHg) and diastole (95.7 ± 12.6 mmHg) than slow progressors (109.5 ± 16.3 and 90.0 ± 13.2 mmHg) (P = 0.04 and P = 0.02, respectively). Mean peripheral blood pressure was significantly higher in fast progressors (102.7 ± 12.8 mmHg) than in slow progressors (97.7 ± 12.9 mmHg) (P = 0.04). Augmentation index did not differ in patients with fast and slow-progressing AAA. However, fast progressors had higher central aortic blood pressures suggesting that elevated aortic blood pressure is a risk factor for faster AAA progression, but this needs to be proven in controlled interventional studies.