Endothelial-Dependent Vasomotor Dysfunction in Infants After Cardiopulmonary Bypass

Area of Science:

• Pediatric Cardiology
• Vascular Biology
• Critical Care Medicine

Background:

• Cardiopulmonary bypass (CPB) can induce endothelial dysfunction, evidenced by changes in pulmonary vascular resistance and capillary leak.
• Systemic endothelial-dependent vasomotor dysfunction following CPB has not been previously quantified in infants.

Purpose of the Study:

• To quantify the acute effects of CPB on endothelial vasomotor control in infants.
• To correlate these effects with postoperative cytokines, tissue edema, and clinical outcomes.

Main Methods:

• A prospective observational pilot study in a pediatric cardiac ICU.
• Laser Doppler perfusion monitoring with iontophoresis of acetylcholine (endothelium-dependent) and sodium nitroprusside (endothelium-independent) was used.
• Measurements were taken preoperatively, 2-4 hours, and 24 hours post-CPB in infants undergoing congenital heart repair.

Main Results:

• CPB significantly decreased endothelium-dependent vasodilation (acetylcholine response) 2-4 hours post-bypass (p=0.0006).
• Endothelium-independent vasodilation (sodium nitroprusside response) remained unchanged.
• Acetylcholine response improved by 24 hours post-CPB but often remained below baseline; preserved function correlated with higher urine output (R=0.43, p=0.008).

Conclusions:

• Infants exhibit cutaneous endothelial dysfunction immediately after CPB, with partial recovery within 24 hours.
• Persistent endothelial dysfunction may be linked to reduced urine output, suggesting clinical significance.
• Further research will investigate the pattern of endothelial dysfunction and its relationship with inflammatory markers and clinical outcomes.