Impairment of pulmonary endothelium-dependent relaxation in patients with Eisenmenger's syndrome.
A comparison has been made between the endothelium-dependent relaxation of pulmonary arteries (PA) obtained at heart-lung transplantation from 4 patients with Eisenmenger's syndrome and secondary pulmonary hypertension, and PA obtained at lobectomy from 4 patients with lung carcinoma, the controls. All vascular rings were studied immediately after lung excision. PA rings from control patients dose-dependently relaxed to cumulative doses of acetylcholine (ACh, 10(-10) to 10(-5) M), achieving a maximal relaxation of 80 +/- 5% (mean +/- s.e. mean) from precontraction with phenylephrine. By contrast, PA rings from Eisenmenger's syndrome patients achieved a maximal relaxation of only 34 +/- 12% (P less than 0.05, unpaired t test), with even paradoxical contraction at high doses of ACh (10(-6) to 10(-5) M). Sodium nitroprusside (10(-4) M) relaxed all PA rings, with and without endothelium (carefully removed before study), obtained from both control and Eisenmenger's syndrome patients. These results provide the first evidence that endothelium-dependent relaxation of PA mediated by endothelium-derived relaxing factors is impaired in Eisenmenger's syndrome patients with secondary pulmonary hypertension.
Dinh Xuan
A T
AT
Department of Respiratory Physiology, Papworth Hospital, Cambridge.
Higenbottam
T W
TW
Clelland
C
C
Pepke-Zaba
J
J
Cremona
G
G
Wallwork
J
J
D000109:Acetylcholine / Q000494:pharmacology; D000293:Adolescent; D000328:Adult; D004541:Eisenmenger Complex / Q000503:physiopathology*; D004730:Endothelium, Vascular / Q000502:physiology*; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D066298:In Vitro Techniques; D009126:Muscle Relaxation / Q000187:drug effects; D009599:Nitroprusside / Q000494:pharmacology; D011651:Pulmonary Artery / Q000503:physiopathology*
D009599:Nitroprusside; D000109:Acetylcholine