Atrial defect size after Blalock-Hanlon atrioseptectomy

Area of Science:

• Cardiovascular Surgery
• Pediatric Cardiology
• Congenital Heart Disease Pathology

Background:

• Transposition of the great arteries (TGA) often requires surgical intervention to improve intracardiac mixing.
• The Blalock-Hanlon closed atrial septectomy is a common palliative procedure for TGA, but its pathological assessment is limited.
• Understanding the anatomical outcomes of this septectomy is crucial for optimizing surgical results in cyanotic congenital heart disease.

Purpose of the Study:

• To pathologically assess the Blalock-Hanlon atrial septectomy in patients with transposition of the great arteries.
• To quantify the atrial communication achieved by the septectomy and identify factors influencing its size.
• To provide recommendations for surgical technique to maximize intracardiac mixing.

Main Methods:

• Analysis of 14 heart specimens from patients with TGA who underwent Blalock-Hanlon septectomy (age 3 days to 19 years).
• Identification of septectomy margins, fossa ovalis, and atrial septum in each specimen.
• Calculation of the total septal defect area and atrial septal area using planimetry.
• Expression of atrial communication as a percentage of the total atrial septal area.

Main Results:

• Atrial communication varied significantly based on the extent of the septectomy.
• Specimens with an intact limbus of the foramen ovale showed 5-39% communication (mean 18%).
• Specimens with excision of the limbus demonstrated 26-57% communication (mean 42%), with larger communication when the defect extended into the fossa ovalis.

Conclusions:

• The extent of the Blalock-Hanlon septectomy directly impacts the degree of atrial communication.
• Extending the septectomy across the limbus into the foramen ovale is essential for achieving optimal bidirectional atrial mixing.
• Pathological evaluation confirms the importance of surgical technique in maximizing the efficacy of the Blalock-Hanlon procedure for TGA.