[Changes in the renin-angiotensin-aldosterone system during open heart surgery. I. Factors involved in renin secretion].

The endocrine, humoral and hemodynamic factors that affect renin secretion are studied during open-heart surgery in a group of 40 patients, 20 with mitral and 20 with aortic valve disease. During the incission period, the PRA (plasma renin activity) increases due to a sympatoadrenergic hyperactivity. These increase is noted also during bypass, and is closely related with the hypotension that extracorporeal circulation produces. It is also discussed the influence of the exclusion of pulmonary circulation, that decreases conversion of angiotensin I to II and catabolism of norepinephrine.