Bronchial arterial response to contrast medium.
OBJECTIVE
Contrast agents have been shown to produce vasodilatory responses in several vascular beds. To our knowledge, however, their effect on the bronchial vasculature has not been examined. Clinically, contrast-induced bronchial vasodilation could potentially exacerbate life-threatening pulmonary hemorrhage during bronchial angiography for hemoptysis. In the current study, we systematically measured the bronchial vasodilatory response to diatrizoate meglumine 66% and diatrizoate sodium 10% (MD-76) and examined whether vasodilation would be mediated by nitric oxide (NO).


METHODS
We measured bronchial blood flow in seven anesthetized, ventilated, open-chested sheep using an ultrasonic flow probe placed around the bronchial artery. Bronchial blood flow was recorded before and after injection of 2 ml MD-76 into the bronchial artery. The protocol was repeated after 20 min infusion of N omega-nitro-L-arginine (L-NA; 10(-2) mol/l), an NO-synthase inhibitor, into the bronchial artery.


RESULTS
There was a 45 +/- 8 ml/min increase (p < .01) in bronchial blood flow after injection of MD-76, which was reduced to 20 +/- 6 ml/min (p < .01) after infusion of L-NA.


CONCLUSIONS
Bronchial arterial injection of MD-76 results in a consistent increase in bronchial blood flow that is mediated partly by NO.
Baile
E M
EM
University of British Columbia Pulmonary Research Laboratory, St. Paul's Hospital, Vancouver, British Columbia, Canada.
Mayo
J R
JR
Sasaki
F
F
Bai
T R
TR
Paré
P D
PD
D000818:Animals; D001981:Bronchial Arteries / Q000187:drug effects*; D003287:Contrast Media / Q000494:pharmacology*; D003973:Diatrizoate / Q000494:pharmacology*; D003974:Diatrizoate Meglumine / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008297:Male; D009569:Nitric Oxide / Q000502:physiology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D019335:Nitroarginine / Q000494:pharmacology; D012039:Regional Blood Flow / Q000187:drug effects; D012756:Sheep; D014665:Vasodilator Agents / Q000494:pharmacology*
D003287:Contrast Media; D004791:Enzyme Inhibitors; D014665:Vasodilator Agents; D003973:Diatrizoate; D019335:Nitroarginine; D009569:Nitric Oxide; D003974:Diatrizoate Meglumine; D019001:Nitric Oxide Synthase