Determinants of systemic vascular resistance in children with congenital heart disease

Area of Science:

• Cardiovascular Physiology
• Pulmonary Hypertension Research
• Congenital Heart Disease

Background:

• Acute changes in systemic arterial oxygen saturation, hemoglobin concentration, and acid-base state are known to alter systemic vascular resistance.
• The persistence of these effects in chronic conditions remains largely uninvestigated.

Purpose of the Study:

• To determine if factors influencing systemic vascular resistance in acute states also affect it in chronic states.
• To investigate the relationship between hemoglobin concentration, systemic arterial oxygen saturation, and acid-base balance with systemic vascular resistance in individuals with congenital heart disease.

Main Methods:

• Systemic vascular resistance was measured in 195 subjects with congenital heart disease.
• Multiple regression analysis was employed to assess the predictive significance of hemoglobin concentration, systemic arterial pH, and oxygen saturation, while accounting for patient size.

Main Results:

• Hemoglobin concentration, systemic arterial pH (or non-respiratory pH), and systemic arterial oxygen saturation were all significantly and positively correlated with systemic vascular resistance (P < 0.025).
• These correlations remained significant even after adjusting for patient size.

Conclusions:

• The physiological mechanisms influencing systemic vascular resistance in acute conditions appear to remain functional in chronic states.
• Hemoglobin concentration, systemic arterial oxygen saturation, and acid-base status are significant determinants of systemic vascular resistance in the chronic setting, particularly in congenital heart disease.