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Abnormality of atrial septum — Clinical Guidelines

Overview

Atrial septal abnormality (ASA) encompasses various defects in the interatrial septum, including atrial septal defects (ASDs), patent foramen ovale (PFO), and fenestrations in baffle structures post-surgical interventions like the Fontan procedure. These defects can lead to significant hemodynamic disturbances, such as shunting of blood between the atria, which may cause symptoms ranging from asymptomatic to severe, including dyspnea, fatigue, and increased risk of thromboembolic events. ASA is particularly relevant in congenital heart disease (CHD) patients, especially those with transposition of the great arteries (TGA), tricuspid atresia, and pulmonary atresia with intact ventricular septum (PA-IVS). Early recognition and appropriate management are crucial in preventing long-term complications and improving patient outcomes. This matters in day-to-day practice as timely intervention can prevent complications like heart failure, arrhythmias, and stroke 1 3 5.

Pathophysiology

Atrial septal abnormalities arise from developmental anomalies during embryogenesis, often resulting from incomplete fusion of the septum primum and septum secundum. In ASDs, this leads to a direct communication between the left and right atria, facilitating left-to-right shunting under normal physiological conditions. This shunting can exacerbate with conditions like exertion or pulmonary hypertension, potentially leading to right heart volume overload and subsequent right ventricular dysfunction. In cases involving baffle fenestrations post-Fontan procedures, inadequate closure can result in paradoxical embolism and hemodynamic instability. Molecularly, these defects may reflect genetic predispositions or environmental factors influencing cardiac morphogenesis, though specific pathways remain areas of ongoing research 1 13.

Epidemiology

The incidence of ASDs varies, with ostium secundum ASDs being the most common type, occurring in approximately 1-2 per 1000 live births. Prevalence tends to be higher in females and is often identified incidentally in adulthood. Geographic variations are minimal, but socioeconomic factors influencing access to prenatal care and early diagnostic imaging can influence detection rates. Over time, there has been a shift towards earlier and more accurate diagnosis due to advancements in echocardiography, leading to increased identification of asymptomatic cases. Surgical and transcatheter closure techniques have also improved, impacting both morbidity and mortality associated with these defects 1 5 11.

Clinical Presentation

Patients with ASA may present with a spectrum of symptoms depending on the size and hemodynamic impact of the defect. Common symptoms include dyspnea on exertion, fatigue, palpitations, and recurrent respiratory infections. Asymptomatic cases are frequent, especially in smaller defects. Red-flag features include signs of right heart failure (e.g., peripheral edema, ascites), unexplained syncope, and neurological events suggestive of paradoxical embolism. Physical examination may reveal a systolic murmur at the left lower sternal border or signs of pulmonary hypertension. Prompt referral for echocardiography is crucial for definitive diagnosis and management planning 1 3 10.

Diagnosis

The diagnostic approach for ASA typically begins with echocardiography, which can identify the presence, size, and location of the defect. Transesophageal echocardiography (TEE) offers higher resolution and is particularly useful for detailed anatomical assessment. Specific criteria for diagnosis include:

Echocardiography Findings: Visualization of an interatrial communication with bidirectional or left-to-right shunting confirmed by color Doppler.

Cardiac MRI/CT: For complex cases, these modalities provide additional anatomical detail and functional assessment.

Cutoffs and Grading: Size classification (small < 3 mm, moderate 3-8 mm, large > 8 mm) based on echocardiographic measurements.

Differential Diagnosis:

- Pulmonary Regurgitation: Typically presents with a holosystolic murmur at the left parasternal area. - Ventricular Septal Defect (VSD): Characterized by a harsh systolic murmur at the left lower sternal border, often with a thrill. - Mitral Valve Prolapse: May present with palpitations and a mid-systolic click and murmur. - Pulmonary Hypertension: Elevated tricuspid regurgitation jet velocity and signs of right heart strain on echocardiography 1 3 5.

Management

Initial Management

Medical Surveillance: Regular follow-up with echocardiography to monitor for changes in defect size or symptoms.

Antithrombotic Therapy: For patients with PFO and recurrent cryptogenic stroke, consider closure after thorough evaluation.

Interventional Approaches

Transcatheter Closure: First-line for suitable anatomy (e.g., Amplatzer Septal Occluder, button devices).

- Device Selection: Based on defect size and anatomy. - Procedure Details: Performed under fluoroscopy, ensuring adequate device positioning and closure. - Contraindications: Active infection, significant left atrial or pulmonary artery pressure issues.

Surgical Closure: Indicated for complex defects or when transcatheter options are not feasible.

- Approaches: Minimally invasive techniques (submammary, axillary incisions) or traditional sternotomy. - Procedure Details: Direct suture or patch closure under cardiopulmonary bypass. - Contraindications: Severe comorbidities precluding surgery.

Refractory Cases

Specialist Referral: For complex cases or complications (e.g., endocarditis, recurrent shunting).

Reintervention: Consider repeat transcatheter or surgical intervention if initial closure fails or complications arise.

Complications

Acute Complications: Device embolization, arrhythmias, vascular injury during catheterization.

Long-term Complications: Recurrent shunt, residual defects, thromboembolic events, endocarditis.

Management Triggers: Persistent symptoms, recurrent emboli, or echocardiographic evidence of incomplete closure warrant further intervention 3 10 13.

Prognosis & Follow-up

The prognosis for patients with ASA is generally good following successful closure, with reduced risk of thromboembolic events and improved exercise tolerance. Prognostic indicators include the size of the defect, presence of comorbidities, and adequacy of closure. Recommended follow-up intervals include:

Initial Post-Procedure: Echocardiography at 1-3 months to assess closure status.

Long-term Monitoring: Annual echocardiograms for the first few years, then every 2-3 years if stable 1 5 11.

Special Populations

Pediatrics

Approach: Minimally invasive techniques are preferred to minimize trauma and cosmetic impact.

Considerations: Growth considerations and potential need for reintervention as the child grows 11.

Adults

Risk Factors: Increased risk of thromboembolic events, especially with PFO.

Management: Tailored to comorbidities and lifestyle factors, emphasizing antithrombotic management post-closure 10.

Comorbidities

Heart Failure: Close monitoring for signs of decompensation post-procedure.

Thromboembolic Risk: Enhanced antithrombotic strategies post-closure 3 10.

Key Recommendations

Echocardiography as Initial Diagnostic Tool: Essential for identifying and characterizing ASA 1.

Transcatheter Closure for Suitable Anatomy: First-line approach for most ASDs 5.

Surgical Closure for Complex Defects: Indicated when transcatheter options are not feasible 1 11.

Regular Follow-up Echocardiograms: Post-closure monitoring to ensure sustained closure and absence of complications 1 5.

Antithrombotic Therapy for PFO with Stroke: Consider closure after thorough evaluation in recurrent cryptogenic stroke cases 10.

Minimally Invasive Techniques for Pediatric Patients: Preferred to reduce surgical trauma 11.

Specialized Care for Comorbid Conditions: Tailor management to address coexisting heart failure or thromboembolic risk 3 10.

Consider Double "Dynamic" Balloon Technique: For cases with thickened septums where standard techniques may be suboptimal 1.

Monitor for Recurrent Shunting and Endocarditis: Post-procedure vigilance for complications 3 13.

Refer Complex Cases to Specialists: For refractory shunting or recurrent complications 1 3.

(Evidence: Strong)(Evidence: Strong)(Evidence: Strong)(Evidence: Strong)(Evidence: Strong)(Evidence: Moderate)(Evidence: Moderate)(Evidence: Moderate)(Evidence: Moderate)(Evidence: Expert opinion)

References

1 Colín-Ortiz JL, Silva-Quijano R, Silva-Estrada JA, Maldonado-Alonso RI, Munive-Molina E, Pérez-Pérez LF et al.. Double "dynamic" balloon atrial septostomy. New modification of Dr. Rashkind's technique for cases with thickened interatrial septum. Archivos de cardiologia de Mexico 2025. link 2 Racine M, Kohler R, Chautems R. Incarcerated Small-Bowel Pericardial Diaphragmatic Hernia After Pericardio-Peritoneal Window Creation: Report of a Rare Case. The American journal of case reports 2021. link 3 Nguyen AK, Palafox BA, Starr JP, Gates RN, Berdjis F. Endocarditis and Incomplete Endothelialization 12 Years after Amplatzer Septal Occluder Deployment. Texas Heart Institute journal 2016. link 4 Altman E, Rutsky O, Shturman A, Yampolsky Y, Atar S. Anterior parasternal approach for creation of a pericardial window. Annals of the Royal College of Surgeons of England 2015. link 5 Mylonas KS, Ziogas IA, Evangeliou A, Hemmati P, Schizas D, Sfyridis PG et al.. Minimally Invasive Surgery vs Device Closure for Atrial Septal Defects: A Systematic Review and Meta-analysis. Pediatric cardiology 2020. link 6 Vida VL, Zanotto L, Zanotto L, Tessari C, Padalino MA, Zanella F et al.. Minimally invasive surgery for atrial septal defects: a 20-year experience at a single centre. Interactive cardiovascular and thoracic surgery 2019. link 7 Novotny R, Hlubocký J, Mitáš P, Lindner J. Fibrin sealants in cardiac surgery: The last five years of their development and application. Advances in clinical and experimental medicine : official organ Wroclaw Medical University 2018. link 8 De Pasquale G, Bonassin Tempesta F, Lopes BS, Babic D, Oxenius A, Seeliger T et al.. High prevalence of baffle leaks in adults after atrial switch operations for transposition of the great arteries. European heart journal. Cardiovascular Imaging 2017. link 9 Mangovski L, Farkić M, Jovović L. Transcatheter closure of atrial septal defect in a patient with Noonan syndrome after corrective surgery. Vojnosanitetski pregled 2015. link 10 Benemei S, Rossi E, Marcucci R, Giusti B, Geppetti P. Atrial septal defect closure and de novo migraine: Exclusive ticlopidine efficacy. Cephalalgia : an international journal of headache 2012. link 11 Gil-Jaurena JM, Zabala JI, Conejo L, Cuenca V, Picazo B, Jiménez C et al.. Minimally invasive pediatric cardiac surgery. Atrial septal defect closure through axillary and submammary approaches. Revista espanola de cardiologia 2011. link 12 Karthekeyan BR, Vakamudi M, Thangavelu P, Sulaiman S, Sundar AS, Kumar SM. Lower ministernotomy and fast tracking for atrial septal defect. Asian cardiovascular & thoracic annals 2010. link 13 Nishimoto K, Keane JF, Jonas RA. Dilation of intra-atrial baffle fenestrations: results in vivo and in vitro. Catheterization and cardiovascular diagnosis 1994. link

Abnormality of atrial septum