Scimitar syndrome is a rare congenital anomaly characterized by partial anomalous pulmonary venous return from the right lung to the inferior vena cava (IVC). An atypical rare variant involves dual drainage—into both the IVC and a left atrial connection—potentially allowing for a catheter-based intervention.

We report three patients diagnosed with atypical scimitar anatomy over a 12-month period at our institution. All underwent multimodal imaging and transcatheter intervention.

Patients were aged 5, 26, and 34 years. Scimitar syndrome was diagnosed incidentally during follow-up for asthma or recurrent respiratory infections. Patients were in NYHA-WHO functional class 2. All presented with dual venous drainage on cardiac CT, confirmed by catheterization. Cardiac MRI showed significant left-to-right shunting and right ventricular dilation. Pulmonary artery pressures were normal in 2 patients (mean pulmonary artery pressure at 17 and 19mmHg) and slightly elevated in one patient (22mmHg). No patient had associated intra-cardiac left to right shunt.

Balloon occlusion testing at the IVC opening of the scimitar vein demonstrated adequate left atrial drainage without pressure elevation. Two patients had stenosis at the IVC connection. All three underwent transcatheter closure of the scimitar vein's IVC connection using amplatzer duct occluder (Fig. 1). Systemic-to-pulmonary collaterals, present in 2 patients, were embolized. All procedures were successful and complication-free. Symptomatic patients reported clinical improvement during follow-up.

In this rare anatomical configuration, transcatheter closure of the anomalous IVC drainage is feasible, safe, and effective. This strategy may prevent long-term complications of chronic left-to-right shunting and represents a minimally invasive alternative to surgery in selected cases.