Abnormal responses for blood pressure in children and adults with surgically corrected aortic coarctation.
BACKGROUND
Despite successful surgical repair of aortic coarctation, life expectancy is reduced, and up to one-third of patients remain or become hypertensive. So as to characterize the responses for blood pressure, we have studied 55 patients with surgically repaired coarctation. Their mean age was 11.3 +/- 5.97 years. We documented maximal uptake of oxygen, anaerobic threshold, plasma renin activity and blood pressures during a Bruce protocol treadmill test. The velocity across the site of repair as imaged by cross-sectional echocardiography was measured before and after exercise. We measured the changes in heart rate and blood pressure subsequent to an infusion of 1 ug per kg of isoprenalin, monitoring blood pressure over 24 hours in all patients.


RESULTS
When compared with 40 healthy age-matched controls, the patients with coarctation had a normal exercise capacity. Resting systolic blood pressures above the 95th percentile were present in 45% of the patients. Exercise-induced hypertension, and an elevation in the average systolic 24 hour blood pressures, were observed, but less frequently than elevated baseline values, suggesting that so-called white-coat" hypertension may be present in this population. Abnormal reactions and elevation of plasma renin activity were related to a history of paradoxical hypertension at the time of surgery. Attenuation of the circadian rhythm for blood pressure was a frequent finding, and may have implications in the development of long-term damage to end-organs. A high correlation was found between mean systolic blood pressure measured by 24 hour monitoring and left ventricular hypertrophy (r=0.65, p<0.05).


CONCLUSIONS
Abnormalities in blood pressure occurred independently of significant mechanical obstruction. Despite successful surgical repair, abnormalities in the shape of the aortic arch, reduced sensitivity of baroreceptor reflexes, and neurohumoral factors may all contribute to the development of hypertension.
Hauser
M
M
Deutsches Herzzentrum, Department of Paediatric Cardiology, Munich, Germany. hauser@dhm.mhn.de
Kuehn
A
A
Wilson
N
N
D000293:Adolescent; D000328:Adult; D001017:Aortic Coarctation / Q000150:complications* / Q000401:mortality / Q000601:surgery*; D001794:Blood Pressure; D016022:Case-Control Studies; D015984:Causality; D002648:Child; D002940:Circadian Rhythm; D004452:Echocardiography; D015716:Electrocardiography, Ambulatory; D005080:Exercise Test; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology*; D017379:Hypertrophy, Left Ventricular / Q000209:etiology; D008017:Life Expectancy; D008297:Male; D010101:Oxygen Consumption; D011183:Postoperative Complications / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology*; D012083:Renin / Q000097:blood; D013599:Systole
D012083:Renin