Related Experiment Videos
Enalapril does not enhance exercise capacity in patients after Fontan procedure
A A Kouatli1, J A Garcia, T M Zellers
1Department of Pediatrics, University of Texas Southwestern Medical Center at Dallas, 75235-9063, USA.
Insights
Enalapril did not improve exercise capacity or cardiac function in patients after a Fontan procedure. This afterload reduction therapy showed no benefits for these individuals.
Area of Science:
- Cardiology
- Pediatric Cardiology
- Cardiovascular Surgery
Background:
- Patients after Fontan procedure exhibit reduced cardiac output and exercise capacity.
- Abnormal diastolic function and increased systemic vascular resistance are common post-Fontan.
- Angiotensin-converting enzyme inhibitors are known to improve cardiac function in heart failure.
Purpose of the Study:
- To evaluate the effects of enalapril on hemodynamic variables and exercise capacity in Fontan procedure patients.
- To determine if afterload reduction therapy can improve outcomes in this population.
Main Methods:
- A randomized, double-blind, placebo-controlled crossover trial was conducted.
- 18 patients (aged 4-19 years post-Fontan) received enalapril or placebo for 10 weeks.
- Doppler assessment of systemic atrioventricular valve flow and graded exercise tests were performed.
Main Results:
- No significant differences were observed in resting heart rate, blood pressure, or cardiac index.
- Diastolic filling patterns remained unchanged between enalapril and placebo treatments.
- Exercise duration and maximal exercise parameters (cardiac index, oxygen consumption, ventilation, work) were not significantly improved by enalapril.
Conclusions:
- Enalapril administration for 10 weeks did not alter systemic vascular resistance, cardiac index, or diastolic function in Fontan patients.
- The study concluded that enalapril does not improve exercise capacity in individuals who have undergone the Fontan procedure.
Background:
Angiotensin-converting enzyme inhibitors improve exercise capacity in adults with congestive heart failure by decreasing systemic vascular resistance and improving ventricular diastolic function. Patients who have undergone the Fontan procedure have decreased cardiac output, increased systemic vascular resistance, abnormal diastolic function, and decreased exercise capacity compared with normal people.
Methods And Results:
To test the hypothesis that afterload reduction therapy alters hemodynamic variables and augments exercise capacity in patients after a Fontan procedure, we compared the results of graded exercise with maximal effort from 18 subjects (14.5+/-6.2 years of age, 4 to 19 years after Fontan procedure) in a randomized, double-blind, placebo-controlled crossover trial using enalapril (0.2 to 0.3 mg x kg[-1] x d[-1], maximum 15 mg). Each treatment was administered for 10 weeks. Diastolic filling patterns at rest were assessed by Doppler determination of the systemic atrioventricular valve flow velocity at the conclusion of each therapy. No difference was detected in resting heart rate, blood pressure, or cardiac index. Diastolic filling patterns were also similar. Exercise duration was not different (6.4+/-2.6 [enalapril] versus 6.7+/-2.6 minutes [placebo]). The mean percent increase in cardiac index from rest to maximum exercise was slightly but significantly decreased in subjects after 10 weeks of enalapril therapy (102+/-34% [enalapril] versus 125+/-34% [placebo]; P<.02). At maximal exercise, cardiac index (3.5+/-0.9 [enalapril] versus 3.8+/-0.9 L x min[-1] x m2 [placebo]), oxygen consumption (18.3+/-9 [enalapril] versus 20.5+/-7 mL x min[-1] x kg[-1] [placebo]), minute ventilation (57.5+/-17 [enalapril] versus 55.4+/-19 L/min [placebo]), and total work (247+/-181 [enalapril] versus 261+/-197 W [placebo]) were not different.
Conclusions:
We conclude that enalapril administration for 10 weeks does not alter abnormal systemic vascular resistance, resting cardiac index, diastolic function, or exercise capacity in patients who have undergone a Fontan procedure.