Hypertension accelerates the growth of experimental aortic aneurysms

Abstract Hypertension has long been suspected to increase the growth rate of abdominal aortic aneurysms (AAA), but there is little experimental evidence to support this hypothesis. Using an established model, aneurysms were induced in normotensive Wistar-Kyoto (WKY) rats and in a unique strain of genetically hypertensive Wistar-Kyoto (WKHT) rats by perfusing an isolated segment of the infrarenal aorta with elastase ( n = 14, each group). Aortic diameter was measured with a micrometer and systolic blood pressure (sBP) determined by tail plethysmography. Rats were killed at 7 or 14 days, aneurysm diameter was measured, and aneurysms were examined histologically. Systolic blood pressure was significantly higher in WKHT rats (164 ± 15 mm Hg) compared to WKY animals (119 ± 7 mm Hg, P P = 0.02) and Day 14 (WKY, 2.36 ± 0.25; WKHT, 3.45 ± 0.89; P = 0.001). Overall, the mean AAA growth rate of the WKYHT group was nearly twice that of the WKY group: 0.13 ± 0.09 mm/day vs 0.07 ± 0.03 mm/day, ( P = 0.004). Growth rates were also positively correlated with sBP ( r = 0.82, P