Baroreceptor reflexes after coarctectomy

Patients with hypertension have a impaired baroreflex sensitivity, the reduction being proportional to the blood pressure elevation. Coarctation of the aorta is characterized by hypertension in the upper part of the body. In eight young men, operated upon for coarctation of the aorta during childhood, baroreflex sensitivity was estimated from the prolongation of the R-R interval during the transient rise of arterial blood pressure induced by intravenous injections of small doses of angiotensin. The patients were compared with normotensive and hypertensive reference groups, of the same age and sex, who were examined in the same way. The resting mean blood pressure in the coarctation group was slightly elevated, and the baroreflex sensitivity was reduced proportionally. The fact that the baroreceptors were more sensitive than would be expected from the patients pre-operative high blood pressure suggests that the baroreceptor-resetting in high blood pressure is to a considerable degree reversible when the blood pressure is reduced.