Can patent ductus arteriosus (PDA) occur in adults?

Yes, Patent Ductus Arteriosus Absolutely Occurs in Adults

PDA is not only possible but well-documented in adults, representing a congenital heart defect that either went undiagnosed in childhood or persisted despite initial detection. The ductus arteriosus normally closes shortly after birth, but when it remains patent into adulthood, it presents with a spectrum of clinical manifestations ranging from completely asymptomatic "silent" PDAs discovered incidentally to severe presentations with Eisenmenger physiology 1.

Epidemiology and Natural History in Adults

• PDA is found in approximately 0.3% to 0.8% of term infants and is twice as common in females as males 1.
• Many adults with PDA represent cases that were either missed in childhood or were small enough not to warrant intervention earlier 2.
• The incidence of adult PDA diagnosis is actually rising due to improved survival of premature infants at risk for PDA and increased incidental discovery on echocardiograms performed for other indications 2.

Clinical Presentations in Adult PDA Patients

The clinical spectrum varies dramatically based on PDA size and pulmonary vascular resistance 1:

Small/Silent PDA

• No left ventricular volume overload with normal pulmonary artery pressure 1.
• Generally asymptomatic and may only have a continuous murmur or be completely silent 1, 3.
• Often discovered incidentally during echocardiography for other purposes 2.

Moderate PDA with Predominant Volume Overload

• Large left ventricle with normal or reduced function 1.
• May present with left heart failure symptoms 1.

Moderate PDA with Predominant Pulmonary Hypertension

• Pressure-overloaded right ventricle 1.
• May present with right heart failure 1.

Large PDA with Eisenmenger Physiology

• Severe pulmonary vascular disease with shunt reversal (right-to-left shunting) 1, 4.
• Differential cyanosis affecting lower extremities and sometimes the left arm 1.
• This represents the most severe end of the spectrum and carries significant morbidity 4.

Critical Diagnostic Approach in Adults

Physical Examination Findings

• Continuous "machinery" murmur is classic but disappears with development of Eisenmenger syndrome 1.
• Bounding pulses and wide pulse pressure may be present 3.
• Differential cyanosis must be assessed by checking oxygen saturation in both feet AND both hands, as cyanosis from right-to-left shunting manifests predominantly downstream from the ductal insertion 1.

Diagnostic Testing

• Echocardiography with color Doppler in the parasternal short-axis view is the key diagnostic technique 1, 3.
• Assessment must include degree of left ventricular volume overload, pulmonary artery pressure, pulmonary artery size, and right heart changes 1.
• Cardiac catheterization is indicated when pulmonary artery pressure is elevated on echocardiography for estimation of pulmonary vascular resistance 1.
• CMR/CT are indicated when additional quantification of left ventricular volumes or evaluation of pulmonary artery anatomy are required 1.

Important pitfall: Large PDAs with Eisenmenger physiology may be difficult to visualize on echocardiography and can be missed, requiring cardiac CT for diagnosis 4.

Management Decisions in Adult PDA

Indications for Closure

PDA closure in adults is recommended (Class I) when:

• Left atrial or left ventricular enlargement is present and attributable to PDA with net left-to-right shunt, pulmonary artery systolic pressure less than 50% systemic, and pulmonary vascular resistance less than one-third systemic 1.

PDA closure may be considered (Class IIb) when:

• Net left-to-right shunt is present with pulmonary artery systolic pressure 50% or greater systemic and/or pulmonary vascular resistance greater than one-third systemic 1.

Absolute Contraindications to Closure

PDA closure should NOT be performed (Class III: Harm) when:

• Net right-to-left shunt exists with pulmonary artery systolic pressure greater than two-thirds systemic or pulmonary vascular resistance greater than two-thirds systemic 1.
• In Eisenmenger physiology, the ductus provides essential decompression for the failing right ventricle and closure would be harmful 1, 5.

Treatment Modality

• Device closure via transcatheter approach is the method of choice in adults 1, 3, 6.
• Surgical closure is reserved for PDAs too large for device closure, distorted ductal anatomy precluding device placement, or calcified PDAs in adults where calcification and tissue friability make surgical manipulation hazardous 1, 3, 6.
• Success rates for transcatheter closure exceed 95% with complete closure approaching 100% in late-term follow-up 6.

Special Considerations and Complications

Endocarditis Risk

• The risk of endarteritis exists but appears to be low in adults with PDA 1.
• Endocarditis prophylaxis is NOT routinely indicated for unrepaired PDA in hemodynamically stable patients 3.
• Prior history of endarteritis is an indication for closure 3.

Rare Complications

• Aneurysm formation of the duct is a rare complication that may even compress the left main coronary artery 1.
• Polycythemia vera can develop in severe cases with Eisenmenger physiology 4.

Surveillance for Stable PDAs

• For hemodynamically stable PDAs without left heart enlargement, observation with routine echocardiographic surveillance every 3-5 years is recommended 3, 6.
• Monitoring should include assessment for development of continuous murmur, bounding pulses, wide pulse pressure, or symptoms of heart failure 3.

Common Pitfalls to Avoid

• Never assume stability based on clinical exam alone—always confirm with echocardiography, as serious complications like pulmonary vascular disease can develop 3.
• Never miss differential cyanosis—always check oxygen saturation in all four extremities to detect right-to-left shunting at the ductal level 1, 3.
• Do not close PDAs in patients with established Eisenmenger physiology, as this is contraindicated and harmful 1.
• In adults, calcification of the PDA may cause problems for surgical closure, making device closure even more preferable 1.