Impaired vasodilation of peripheral arteries in response to acetylcholine in human beings with abdominal aortic aneurysm.
OBJECTIVE
Most aneurysms are generally presumed to be atherosclerotic in origin. Endothelium-dependent dilations were impaired in the cases of atherosclerosis. It is not clear whether the endothelial function of the peripheral arteries in humans with abdominal aortic aneurysm is impaired. The purpose of this study is to characterize endothelium-dependent relaxations in patients with abdominal aortic aneurysm.


METHODS
Responses of external iliac artery blood flow to acetylcholine (30 micrograms/min: an endothelium-dependent vasodilator) and sodium nitroprusside (10 micrograms/min: a direct dilator of smooth muscle) were examined by electromagnetic blood flow meter in a group of 13 patients consisting of six patients with abdominal aortic aneurysm, six patients with colorectal cancer, and one patient with abdominal aortic aneurysm and rectal cancer.


RESULTS
The mean blood flow before administration of drugs was comparable between the two groups. In the patients with abdominal aortic aneurysm, infusion of acetylcholine did not significantly increase the mean blood flow, whereas in the patients with colorectal cancer, acetylcholine increased the blood flow significantly. The increases of blood flow by an infusion of sodium nitroprusside were comparable between the two groups. In one patient with abdominal aortic aneurysm and rectal cancer, acetylcholine did not alter the blood flow, and sodium nitroprusside increased the blood flow, which was similar to what the patient with abdominal aortic aneurysm experienced.


CONCLUSIONS
These results suggest that in patients with abdominal aortic aneurysm, the endothelium-dependent vasodilations of the peripheral artery were impaired without changing the smooth muscle property.
Second Department of Surgery, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
K
K
Komori
K
K
Mawatari
H
H
Itoh
K
K
Sugimachi
D000109:Acetylcholine / Q000494:pharmacology*; D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000150:complications / Q000503:physiopathology*; D001783:Blood Flow Velocity / Q000187:drug effects; D015179:Colorectal Neoplasms / Q000150:complications / Q000503:physiopathology*; D055590:Electromagnetic Phenomena; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007083:Iliac Artery / Q000187:drug effects* / Q000503:physiopathology*; D007261:Infusions, Intra-Arterial; D008297:Male; D008875:Middle Aged; D009599:Nitroprusside / Q000494:pharmacology*; D012004:Rectal Neoplasms / Q000150:complications / Q000503:physiopathology*; D012212:Rheology; D014664:Vasodilation / Q000187:drug effects
D009599:Nitroprusside; D000109:Acetylcholine