Ductus Venosus: Definition and Management of Persistent Patency in Newborns
The ductus venosus is a fetal vascular channel connecting the umbilical vein to the inferior vena cava that normally closes within the first 1-2 weeks after birth; when it remains patent beyond this period and causes complications, transcatheter device closure is the preferred treatment approach.
What is the Ductus Venosus?
The ductus venosus (DV) is a physiological fetal shunt that allows oxygenated blood from the umbilical vein to bypass the liver and flow directly into the inferior vena cava. This vessel serves a critical role in fetal circulation but becomes unnecessary after birth when the umbilical circulation ceases.
Normal Closure Timeline
- Full-term infants: The DV typically closes within 1-2 days after birth 1
- Premature infants (33-36 weeks): Patent in 56% at 1 week, 14% at 2 weeks, and closes by 3 weeks 2
- Very premature infants (28-32 weeks): Patent in 85% at 1 week, 42% at 2 weeks, and 27% at 3 weeks 2
Important caveat: In the first weeks of life, a patent DV should be recognized as a normal physiological finding and not mistaken for a pathological portosystemic shunt 1.
Clinical Significance of Persistent Patent Ductus Venosus
When the DV remains patent beyond the expected closure period, it functions as a congenital portosystemic shunt, bypassing hepatic circulation and causing multisystem complications 3, 4.
Key Clinical Presentations
The most common initial presentations include 4:
- Cholestatic jaundice (hyperbilirubinemia in 7/9 patients)
- Respiratory symptoms with tachypnea
- Recurrent respiratory infections
Serious Complications
Persistent patent DV can lead to life-threatening conditions 4, 5:
- Pulmonary arterial hypertension (PAH): Most serious cardiovascular consequence, with systolic PA pressures reaching 106 mm Hg in documented cases
- Hyperammonemia and hepatic encephalopathy: Due to ammonia bypassing hepatic metabolism (found in 4/9 patients in one series)
- Hypersplenism: Leading to leukocytopenia and thrombocytopenia
- Hepatic dysfunction: Abnormal liver enzymes in 8/9 patients
- Coagulation abnormalities: Present in 6/9 patients
- Renal dysfunction: Documented in 3/9 patients
Diagnostic Approach
Imaging Findings
Direct imaging sign: A vascular structure connecting the left branch of the portal vein to the inferior vena cava 4
Secondary imaging findings (present in virtually all cases) 4:
- Dilated right heart chambers
- Dilated pulmonary artery
- Dilated left portal vein branch
- Atrophic right portal vein branch
- Hepatomegaly (8/9 patients)
- Splenomegaly (8/9 patients)
- Hypoperfusion of right hepatic lobe
Laboratory Abnormalities to Assess
- Arterial blood gas (hypoxemia)
- Ammonia levels (hyperammonemia)
- Liver function tests (bilirubin, transaminases)
- Coagulation profile (PT/INR, PTT)
- Complete blood count (cytopenias from hypersplenism)
- Myocardial enzymes
- Renal function
Hemodynamic Assessment
Critical preoperative evaluation 6, 5:
- Echocardiography to estimate pulmonary artery pressures
- Right heart catheterization for precise PA pressure and pulmonary vascular resistance
- Balloon occlusion test: Essential to measure portal vein pressure during test occlusion of the DV to determine if closure is safe
Treatment Algorithm
Step 1: Initial Stabilization
For patients with PAH, initiate combination pharmacotherapy with bosentan and tadalafil before intervention 5. This approach is safe and effective in reducing pulmonary pressures.
Step 2: Assess Candidacy for Closure
Perform balloon occlusion angiography to:
Closure is appropriate when:
- Portal vein pressure remains normal during test occlusion
- Adequate intrahepatic portal venous branches are present
- Patient has symptomatic complications (jaundice, PAH, hyperammonemia, hypersplenism)
Closure is contraindicated when:
- Exceedingly high portal pressures during test occlusion
- Severe portal vein hypoplasia with only diminutive branches
- In these cases, liver transplantation may be the only option 3, 6
Step 3: Choose Intervention Method
Transcatheter device closure is the preferred treatment approach 7, 8, 6:
Device options:
- Amplatzer vascular plug II (for large shunts up to 22 mm) 8
- Figulla Flex II atrial septal defect occluder (for huge shunts with severe portal vein hypoplasia) 6
- Standard vascular plug devices 7
Advantages of transcatheter approach:
- Less invasive than surgery
- Can be performed in staged procedure if needed
- Devices licensed for other indications (ASD closure) can be safely adapted 6
Surgical ligation remains an alternative when:
- Anatomy is unfavorable for device closure
- Transcatheter approach fails
- Local expertise favors surgical approach 4, 5
Step 4: Timing of Intervention
Early surgical or transcatheter closure is recommended once complications develop 4. However, timing should be individualized based on:
- Severity of complications (PAH, encephalopathy, hypersplenism)
- Portal vein development and pressures
- Patient age and size (larger patients may have more favorable anatomy) 6
Step 5: Post-Intervention Monitoring
Expected improvements after successful closure 5:
- Normalization of pulmonary artery pressures
- Resolution of hyperammonemia
- Improvement in liver function
- Normalization of blood cell counts
- Weight gain and improved exercise tolerance
Critical Pitfalls to Avoid
Do not mistake physiologic patent DV in the first 1-3 weeks of life for pathology 1, 2
Do not proceed with closure without balloon occlusion testing - this can lead to catastrophic portal hypertension if portal vein is hypoplastic 6
Do not miss associated malformations - 7/9 patients in one series had coexisting abnormalities, most commonly congenital heart disease and vascular anomalies 4
Do not delay treatment once complications develop - multisystem damage progresses and may become irreversible 4
Do not overlook the need for preoperative PAH management - combination therapy should be initiated before intervention in patients with elevated PA pressures 5