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Abnormal responses for blood pressure in children and adults with surgically corrected aortic coarctation
1Deutsches Herzzentrum, Department of Paediatric Cardiology, Munich, Germany. hauser@dhm.mhn.de
Insights
Patients with repaired coarctation of the aorta often experience hypertension due to factors beyond mechanical obstruction. This study highlights abnormal blood pressure regulation and its links to long-term cardiovascular health.
Area of Science:
- Cardiovascular Medicine
- Pediatric Cardiology
- Hypertension Research
Background:
- Aortic coarctation repair improves life expectancy but hypertension persists in up to one-third of patients.
- Understanding blood pressure responses post-repair is crucial for long-term patient management.
- This study investigates hemodynamic and neurohumoral factors in surgically repaired coarctation patients.
Purpose of the Study:
- To characterize blood pressure responses in patients with surgically repaired coarctation of the aorta.
- To identify factors contributing to persistent or new-onset hypertension after coarctation repair.
- To correlate hemodynamic measurements with long-term cardiovascular outcomes.
Main Methods:
- Studied 55 patients with surgically repaired coarctation (mean age 11.3 years).
- Assessed maximal oxygen uptake, anaerobic threshold, plasma renin activity, and blood pressure during treadmill testing.
- Measured echocardiographic velocity at the repair site, and monitored 24-hour blood pressure and heart rate response to isoproterenol.
Main Results:
- Patients exhibited normal exercise capacity but 45% had high resting systolic blood pressure.
- Exercise-induced hypertension and elevated 24-hour systolic blood pressure were noted.
- Abnormal plasma renin activity correlated with surgical history; attenuated circadian blood pressure rhythm was frequent.
- Mean 24-hour systolic blood pressure strongly correlated with left ventricular hypertrophy (r=0.65, p<0.05).
Conclusions:
- Hypertension post-coarctation repair is not solely due to residual mechanical obstruction.
- Aortic arch abnormalities, reduced baroreceptor sensitivity, and neurohumoral factors contribute to hypertension.
- These findings underscore the need for ongoing cardiovascular monitoring in repaired coarctation patients.
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.