Inferior sinus venosus defects: anatomic features and echocardiographic correlates

Area of Science:

• Cardiology
• Pediatric Cardiology
• Cardiac Surgery

Background:

• Inferior sinus venosus defects (SVDs) are rare atrial septal defects involving the inferior vena cava (IVC) and left atrium.
• These defects are often misdiagnosed as secundum atrial septal defects (ASDs) with inferior extension.
• Inferior SVDs carry an increased risk of anomalous pulmonary venous return (PAPVR).

Purpose of the Study:

• To review institutional experience with inferior SVDs.
• To establish a precise echocardiographic definition to differentiate inferior SVDs from secundum ASDs with inferior extension.
• To improve diagnostic accuracy for guiding treatment strategies.

Main Methods:

• Retrospective review of 161 patients (1.5-32 years) who underwent repair for secundum ASD with inferior extension or inferior SVD.
• Analysis of surgical notes, preoperative transthoracic echocardiograms (TTEs), and transesophageal echocardiograms (TEEs).
• Application of a strict anatomic and echocardiographic definition by blinded observers for reclassification.

Main Results:

• 91% of patients were initially diagnosed with secundum ASD, and 9% with inferior SVD.
• TTE and surgical diagnosis correlated in 89% of cases.
• A strict echocardiographic definition led to correct reclassification in 78% of TTE reviews and 100% of TEE reviews.

Conclusions:

• Accurate diagnosis of inferior SVDs remains challenging.
• A strict echocardiographic definition, focusing on the defect's origin at the IVC mouth and extension into the left atrium, enables accurate differentiation.
• This distinction is vital for selecting appropriate surgical or device closure interventions for these rare defects.