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Sympathetic activity in children undergoing balloon valvuloplasty of pulmonary stenosis
1Department of Cardiovascular Diseases, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia.
Insights
Balloon valvuloplasty normalizes elevated alpha-adrenoceptor density in pulmonary stenosis patients. Beta-adrenoceptor density also improves post-procedure, indicating acute effects on sympathetic function.
Area of Science:
- Cardiology
- Pediatric Cardiology
- Pharmacology
Background:
- Pulmonary stenosis is a condition affecting heart valve function in children.
- Adrenoceptor and catecholamine levels may be altered in pediatric cardiovascular diseases.
Purpose of the Study:
- To investigate the impact of balloon valvuloplasty on adrenoceptor densities and catecholamine levels in children with pulmonary stenosis.
- To compare these changes with a control group undergoing patent ductus arteriosus occlusion.
Main Methods:
- Measured alpha- and beta-adrenoceptor densities, plasma catecholamines (norepinephrine, epinephrine, dopamine), and cyclic AMP (cAMP) levels.
- Assessed levels before and 10 minutes after balloon valvuloplasty in pulmonary stenosis patients (n=31).
- Used children undergoing transcatheter occlusion of patent ductus arteriosus (n=15) as controls.
Main Results:
- Alpha-adrenoceptor density was significantly higher in pulmonary stenosis patients before valvuloplasty, decreasing to control levels post-procedure.
- Beta-adrenoceptor density was lower in pulmonary stenosis patients, increasing towards control levels after valvuloplasty.
- Plasma dopamine and cAMP levels were elevated in pulmonary stenosis patients and remained high after the procedure.
Conclusions:
- Balloon valvuloplasty acutely normalizes elevated alpha-adrenoceptor density in pediatric pulmonary stenosis.
- The procedure also increases attenuated beta-adrenoceptor density, suggesting a significant impact on sympathetic functional status.
Abstract:
We studied the influence of balloon valvuloplasty on alpha- and beta-adrenoceptor densities, plasma catecholamine, and cAMP levels in children and infants with pulmonary stenosis before and 10 min after balloon dilatation, employing as controls children undergoing transcatheter occlusion of patent ductus arteriosus (PDA) with Qp/Qs ratio < 1.5. In the PDA group, the alpha-adrenoceptor density (Bmax) was 3.75 +/- 0.72 fmol/10(7) cells (n = 15) before occlusion and remained unchanged at 3.35 +/- 0.47 fmol 10 min thereafter. In the pulmonary stenosis patients (n = 31), the receptor density was 59% higher (p < 0.05) before, and decreased to PDA levels 10 min after, the procedure. The control beta-adrenoceptor density was 64.8 +/- 11.0 fmol/10(6) cells before, and 71.2 +/- 13.2 fmol 10 min after, occlusion. In the study group, the density was 23% lower (p < 0.07) and increased to the PDA levels 10 min after the dilatation. Compared with the PDA, pre- and postdilatation plasma norepinephrine levels were not significantly changed; epinephrine was slightly elevated before, but increased by 73% after, dilatation; dopamine was 80% (p < 0.05); and cAMP was 37% higher before, and remained elevated at 70 and 23% above the PDA values after, the procedure. Accordingly, alpha-adrenoceptor density is significantly elevated in children with pulmonary stenosis and decreases significantly immediately after balloon valvuloplasty. On the other hand, beta-adrenoceptor density is attenuated and increases toward normal levels after the procedure. The immediate reversal of the receptor levels after balloon valvuloplasty suggests that this procedure exerts acute effects on the sympathetic functional level in this disease.