Aortopulmonary window (APW) is a rare congenital malformation characterised by an abnormal communication between the ascending aorta and the pulmonary artery, despite the presence of separate semilunar valves. This embryologic defect, resulting from incomplete fusion of the conotruncal septum, accounts for less than 0.2% of all congenital heart diseases.1,2 The defect generates a left-to-right shunt, leading to volume overload, progressive pulmonary hypertension, and, in advanced stages, heart failure.
Diagnosis is typically established through transthoracic or transoesophageal echocardiography, thoracic CT angiography (CTA), and cardiac catheterisation.3 These modalities are essential to assess the morphology of the defect, haemodynamic impact, and the presence or severity of pulmonary hypertension.4
Treatment depends on the size of the defect, the age of the patient, and associated complications, such as severe pulmonary hypertension.5 Traditionally, APW closure has been performed surgically via sternotomy. However, recent advances in interventional cardiology have enabled the development of less invasive percutaneous techniques, including the use of occlusion devices, such as the Amplatzer Septal Occluder (ASO), which has shown increasingly favourable outcomes.6,7
The ASO, one of the most widely used devices for septal defect closure, is made of nitinol mesh and designed with expandable discs that allow secure anchoring and low risk of embolisation.3 Its structure facilitates percutaneous implantation and minimises residual complications. In APW, the device is deployed under fluoroscopic and echocardiographic guidance, achieving effective defect closure.8 Its use has demonstrated technical success, reduced postoperative morbidity, and faster recovery, especially in selected patients with small to moderate defects.9 Compared to surgical alternatives, it significantly lowers the risks of infection, haemorrhagic complications, and prolonged hospitalisation.10 Nevertheless, the procedure is not without potential adverse events, including haemolysis, haematuria, arrhythmias, or vascular access-related complications.
In this context, we report the case of a young woman with a diagnosis of type 1 APW and severe pulmonary arterial hypertension (PAH) who was successfully treated by percutaneous closure using the ASO. We describe the diagnostic approach, procedural details, postoperative complications, including haemolytic anaemia and haematuria, and favourable clinical evolution during follow-up.
Case Report
A 25-year-old woman from Los Ríos Province, Ecuador, with no known congenital heart disease at birth or during early childhood, reported symptoms beginning between the ages of 5 and 6, including exertional dyspnoea, dizziness, palpitations and episodes of near-syncope. At age 9, a cardiac murmur was detected during medical evaluation and an APW was diagnosed. However, her mother declined surgical correction due to economic constraints and perceived procedural risks. The patient, who is from a low-income background, has an obstetric history of two caesarean deliveries at ages 16 and 22.
In 2024, the patient was referred for specialised cardiac evaluation due to acute decompensation. At presentation, she complained of retrosternal chest pain (rated 6/10 on the visual analog scale), headache, dyspnoea and transient loss of consciousness lasting approximately 4 minutes. On examination, she was tachycardic (112 BPM), hypotensive (90/50 mmHg), with an oxygen saturation of 93%, and showed signs of peripheral hypoperfusion. Physical findings included a continuous grade IV/VI murmur, jugular venous distension (grade II), and diminished breath sounds at the right lung base.
Initial electrocardiogram revealed sinus rhythm, frontal axis +10°, PR interval 180 ms, QRS 100 ms, and isoelectric ST segment. Signs of right-axis deviation, prolonged intrinsic deflection, left atrial enlargement, and left ventricular systolic overload were noted. Laboratory tests showed elevated N-terminal pro-B-type natriuretic peptide (3,078 pg/ml), haemoglobin 12 g/dl, haematocrit 36%, and creatinine 0.6 mg/dl. Initial management included IV furosemide infusion, as needed nitroglycerin, sodium-restricted diet, head-of-bed elevation, strict fluid balance, and diuresis control.
While transthoracic echocardiography raised suspicion of an intracardiac shunt, transoesophageal echocardiography (TOE) clearly demonstrated a type 1 APW with a left-to-right shunt, a dilated left ventricle with preserved systolic function with a left ventricular ejection fraction (LVEF) of 50%, and an enlarged left atrium without right-sided chamber involvement. These findings were confirmed by thoracic CTA (Figure 1).
Given the long-standing nature of the defect and the absence of prior intervention, surgical correction was initially discussed. However, the patient expressed reluctance to undergo conventional surgery due to the perceived procedural risk. After a multidisciplinary assessment that included clinical cardiology, interventional cardiology and cardiovascular surgery, the team proposed percutaneous closure as a feasible and less invasive alternative, supported by favourable anatomical features and a positive vasoreactivity test.
Right and left heart catheterisation confirmed severe PAH, with an mPAP of 50 mmHg, a Qp/Qs ratio of 2.4:1, and elevated pulmonary vascular resistance (PVR) of 4.2 Wood units. A vasoreactivity test using 100% oxygen demonstrated a significant haemodynamic improvement. The mPAP decreased by 10% and the PVR was reduced by 46% (Table 1 ), confirming pulmonary vascular reactivity and supporting the feasibility of percutaneous closure. During hospitalisation, the patient also developed a urinary tract infection caused by Escherichia coli, which was effectively treated with piperacillin/tazobactam (4.5 g IV every 6 hours for 5 days).
Once clinically stabilised, percutaneous defect closure was performed using a 14 mm ASO, guided by fluoroscopy and intraoperative TOE. Arterial and venous femoral access was established, and an arteriovenous loop was formed. A sizing balloon (18 mm) was used to measure the defect. The procedure was completed successfully, with proper device placement and minimal residual flow. A grade I–II/VI continuous systolic murmur at the upper left sternal border, corresponding to the trivial residual shunt, was noted and resolved spontaneously during follow-up.
Postoperatively, the patient was transferred to the critical care unit for monitoring. She developed progressive anaemia with laboratory signs of haemolysis: elevated lactate dehydrogenase (2,826 U/l), indirect hyperbilirubinemia (3.07 mg/dl), and schistocytes on peripheral smear. Coombs test was negative. Haematuria was also noted and evaluated with urogram CT, which revealed no structural abnormalities. Anaemia was managed with oral folic acid 5 mg/day and subcutaneous erythropoietin (5,000 IU/day). Medical therapy included aspirin 100 mg/day and carvedilol (6.25 mg twice daily).
Serial echocardiograms confirmed correct device positioning and shunt resolution. Figure 2 illustrates pre- and post-intervention Doppler flow characteristics. The left ventricle remained dilated (Figure 3), with preserved systolic function (LVEF 54%), an enlarged left atrium, and normal right heart chambers, without pericardial effusion. Follow-up echocardiography also confirmed laminar flow in the right pulmonary artery, without turbulence or evidence of obstruction.
ECG monitoring revealed isolated ventricular extrasystoles, which were self-limited and required no intervention. The patient remained afebrile, normotensive and did not require supplemental oxygen. She was discharged after 36 days at New York Heart Association functional class I, with instructions for monthly haematologic surveillance and regular cardiology follow-up.
During her first week post-discharge, the patient experienced intense thoracic pain (rated 7/10), which resolved after 2 weeks and was not associated with any acute complications. Overall, she reported clinical improvement with resolution of palpitations, dyspnoea, and exertional chest pain – previously worsened by cold weather – as well as reduced headache frequency and improved exercise tolerance.
At the 3-month follow-up, echocardiography showed a severely dilated left ventricle (end diastolic diameter 6.5 cm) with mildly reduced systolic function (biplane LVEF 45%) and anteroseptal hypokinaesia. Global longitudinal strain was reduced (−11.2%), and indexed left ventricular mass was elevated (222.88 g/m²). The left atrium was severely enlarged (67.65 ml/m²), with grade I diastolic dysfunction and normal filling pressures. Mild regurgitation was observed in the aortic, pulmonary, and tricuspid valves. Right ventricular size and function remained normal (tricuspid annular plane systolic excursion 2.6 cm; S wave 13 cm/s).
The ASO device remained in optimal position with no residual shunt. Estimated systolic pulmonary artery pressure had decreased to 36 mmHg (mean pressure 19 mmHg; PVR 71 dyn·s/cm5), showing significant improvement from baseline (mPAP 50 mmHg). No pericardial effusion or volume overload signs were detected on the inferior vena cava 1.4 cm, with >50% inspiratory collapse; estimated right atrial pressure 5 mmHg.
Discussion
This case is notable for involving a 25-year-old woman with a diagnosis of APW in childhood who, despite not undergoing surgical correction, remained clinically compensated until presenting with acute decompensated heart failure. The medical records do not clarify why corrective surgery was not performed during childhood, raising questions about possible social, economic or healthcare system barriers that delayed appropriate treatment.
Initially, transthoracic echocardiography raised diagnostic uncertainty, suggesting a possible atrial septal defect or persistent ductus arteriosus. It was TOE that clearly delineated the anomalous communication between the ascending aorta and pulmonary trunk, confirming the diagnosis of a type 1 APW. This underscores the diagnostic value of TOE in adults with atypical or poorly characterised congenital heart disease.
Acute presentation triggered a multidisciplinary assessment, which identified a type 1 APW associated with severe PAH, which is generally considered a relative contraindication to defect closure due to the risk of precipitating right ventricular failure or Eisenmenger syndrome. The patient’s positive vasoreactivity test supported the feasibility of intervention. This clinical decision was critical, especially in the absence of formal guidelines for transcatheter APW closure in adults with advanced PAH – most literature on the topic consists of paediatric case series and reports.11,12
A 14 mm ASO device was selected based on balloon sizing (18 mm) and the availability of adequate anatomical rims, ensuring distance from the semilunar valves and coronary ostium – criteria described in previous paediatric and adult series.13,14
During the immediate postoperative period, the patient developed progressive anaemia due to non-immune haemolysis and gross haematuria. These complications were likely related to minimal residual flow across the device, as described in previous reports.3,15 Haemolysis was managed with subcutaneous erythropoietin and oral folic acid, without the need for reintervention. Haematuria persisted for approximately 1 month after discharge, and the patient reported malodorous urine for nearly 2 months, although urological imaging revealed no anatomical abnormalities.
At 3-month follow-up, the device remained in proper position with no residual shunting, confirming the technical success of the procedure. Nevertheless, mild left ventricular systolic dysfunction was documented (LVEF 45%) along with anteroseptal hypokinaesia and reduced global longitudinal strain (−11.2%). These findings may reflect chronic myocardial remodelling or irreversible structural damage prior to closure. Severe left atrial dilation and grade I diastolic dysfunction were also observed, without elevated filling pressures, suggesting persistent left-sided volume overload despite shunt closure.
From a haemodynamic perspective, pulmonary artery systolic pressure decreased from 50 to 36 mmHg, with a mean pressure of 19 mmHg and pulmonary vascular resistance of 71 dyn·s/cm5. These findings indicate a favourable vascular response post-intervention and reaffirm the value of preprocedural vasoreactivity testing for candidate selection.
This case also emphasises the importance of comprehensive patient care. Management extended beyond the technical procedure to include clinical stabilisation, infection control, complication management, and structured follow-up. This holistic strategy contributed to a favourable outcome and aligned with current recommendations for managing complex congenital heart disease in adults.
Among the strengths of the case are optimal patient selection, use of advanced diagnostic tools (echocardiography, CTA, catheterisation), and individualised therapeutic planning. Limitations include the absence of a formal rationale for erythropoietin use, lack of detailed anatomical correlation between the defect and valvular structures, and the short-term nature of follow-up, which limits assessment of long-term ventricular remodelling and haemodynamic evolution.
Conclusion
Percutaneous closure of an APW in young adults with severe pulmonary hypertension may be feasible and safe when vasoreactivity and favourable anatomy are present. Although not the standard approach, use of an ASO achieved effective shunt elimination and reduced pulmonary artery pressure. Multidisciplinary care and structured follow-up remain essential to ensure clinical stability and monitor long-term outcomes.
Clinical Perspective
- Uncorrected aortopulmonary window usually causes severe clinical manifestations, often becoming symptomatic shortly after birth and potentially leading to heart failure or even death within the first months of life. In rare cases, patients may remain apparently stable for years and reach adulthood before decompensation occurs.
- Percutaneous closure using the Amplatzer Septal Occluder device is a viable option in patients with reversible pulmonary hypertension, achieving significant postprocedural pressure reduction.
- Persistent mild systolic dysfunction and left atrial dilation following closure highlight the need for structured echocardiographic monitoring.
- In cases of minimal or haemodynamically insignificant residual flow, a conservative medical approach may be considered without requiring reintervention.