Abdominal aortic aneurysm expansion rate: effect of size and beta-adrenergic blockade

Abstract

Purpose: The purpose of this study was to investigate the hypothesis that abdominal aortic aneurysm (AAA) expansion may be slowed by beta-adrenergic antagonists.

Methods: One hundred twenty-one patients with infrarenal AAA were monitored with serial aortic ultrasound examinations. Eighty-three patients received no beta-blockers (group I), and 38 patients received beta-blockers (group II). Values are expressed as mean +/- SD.

Results: The mean follow-up was 43 +/- 29 months with 5.5 +/- 3.4 ultrasound examinations per patient. The expansion rate among all AAA was 0.38 +/- 0.44 cm/yr. Large aneurysms (> or = 5 cm) expanded significantly faster than small aneurysms (p = 0.02) in patients not treated with beta-blockers. Among patients with large AAA, those receiving beta-blockers had a significantly reduced mean expansion rate; 0.36 +/- 0.20 versus 0.68 +/- 0.64 cm/yr, (p < 0.05). Although rupture rates were lower in group I (5%) versus group II (13%), this difference was not statistically significant. Thirty-four patients in a poor-risk category with AAA were monitored greater than 5 cm in diameter. Ten of these AAA ruptured. The mean expansion rate was significantly greater in those patients with ruptured AAA versus those patients with AAA that did not rupture; 0.82 +/- 0.74 versus 0.42 +/- 0.41 cm/yr (p = 0.04).

Conclusions: In patients not undergoing beta-blocker therapy, large AAA expand at a significantly greater rate than smaller AAA. Large aneurysms that rupture show more rapid expansion than those AAA that do not rupture. We have demonstrated a significantly reduced rate of expansion of large AAA in patients receiving beta-blockade.