ASD rims to be assessed to decide device closure vs surgical closure

 ASD Rims to be assessed on Echocardiography

These are usually assessed on Transesophageal Echocardiogram.

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ASD rims to be assessed to decide device closure vs surgical closure

A practical, evidence-based clinical review

Summary (TL;DR)

When planning closure of a secundum atrial septal defect (ASD), careful assessment of the surrounding rims (tissue margins) is essential. Adequate rims (commonly ≥5 mm) allow safe transcatheter/device closure in most cases; deficient or absent rims (especially posteroinferior/IVC or very large defects with insufficient surrounding tissue) and other anatomic issues favour surgical repair. Modern imaging (TTE, TEE — including 3D TEE — and intracardiac echo) defines defect size, shape, number, and rim quality; device choice and sizing, patient age, comorbidities and operator experience then determine whether to attempt percutaneous closure or refer for surgery. 

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1. Why rims matter — the anatomy and mechanics

A secundum ASD is surrounded by several "rims" of septal tissue that provide anchoring surface for device disks. The device (for example, an Amplatzer-type occluder) closes the defect by sandwiching the septum between its two discs; the discs require firm rim tissue to grip and to avoid embolization, malposition, or erosion into adjacent structures (aorta, atrial wall). If rims are absent or very floppy, the device may not seat securely or may impinge adjacent structures. 

Commonly assessed rims (descriptions clinicians use):

Aortic (anterosuperior / retroaortic) rim — between defect and aortic root.

Superior rim — toward the superior vena cava (SVC).

Posterior rim — toward pulmonary veins.

Inferior / posteroinferior (IVC) rim — toward inferior vena cava.

Anteroinferior (AV valve) rim — adjacent to tricuspid/mitral inflow.

Assess each rim for presence, width (mm), consistency (firm vs floppy) and relation to adjacent structures (e.g., absence of aortic rim but with adequate surrounding tissue may still allow closure in selected cases). 

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2. How to assess rims — imaging modalities & measurements

Modalities

Transthoracic echocardiography (TTE) — first-line; good for screening and sizing in many children and thin adults.

Transesophageal echocardiography (TEE) — 2D and 3D — gold standard for detailed rim assessment and intraprocedural guidance in most adults and complex cases. 3D TEE gives superior spatial understanding of rim geometry.

Intracardiac echocardiography (ICE) — frequently used during intervention to avoid general anaesthesia; excellent for live procedural guidance.

Cardiac CT / MRI — adjuncts in complex anatomy or when echo windows are poor. 

What to measure & thresholds

Measure the maximal defect diameter (multiple planes) and the minimal rim widths.

A commonly used practical cutoff: rims <5 mm are considered deficient (though the clinical meaning depends on rim location and tissue quality). Many interventionalists require ≥5 mm of rim for safe standard device implantation; however, successful device closure has been reported with deficient aortic rims in experienced centers. 

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3. Which rim deficits matter most?

Evidence shows the risk profile differs by rim location:

Aortic rim deficiency (absent/very small anterosuperior rim) is common. Multiple contemporary series show many such defects can still be closed percutaneously with careful technique, but an absent aortic rim has been associated in some reports with higher risk of device-related erosion when combined with other risk factors (oversized device, deficient other rims). 

Posteroinferior / IVC rim deficiency and posterior rim deficiency have been associated with higher rates of residual shunt, device instability, and procedural complications in pooled analyses; these rim deficiencies more often push toward surgical repair. 

Floppy or atrialized rims (tissue present but mobile/fragile) are risk factors for embolization; careful sizing and operator experience are paramount. 

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4. Decision principles — device vs surgery

Use an integrated assessment; no single rim measurement automatically mandates surgery. Consider:

Favouring transcatheter/device closure

Secundum ASD with adequate rims (generally ≥5 mm) around most of the circumference or at least sufficient tissue where device discs can sit.

Single defect or multiple defects amenable to a single device (or with fenestrated device strategies).

Defect size within device availability (many devices available up to ~38–40 mm nominal; very large defects may still be closed in expert centers with special techniques).

No other cardiac anomalies requiring open surgery (e.g., primum ASD, sinus venosus ASD, significant AV valve defects, anomalous pulmonary venous return).

Patient preference and acceptable surgical risk. 

Favouring surgical closure

Non-secundum ASD types (primum, sinus venosus, coronary sinus defects) — generally surgical.

Very large defects with multiple rim deficiencies or rim tissue <5 mm in critical locations (particularly posteroinferior/IVC or posterior rims) and inadequate atrial tissue to secure device.

Associated anomalies requiring surgery (e.g., partial anomalous pulmonary venous connection).

Unfavourable septal geometry (multiple large defects widely separated) not amenable to device strategies.

Recurrent device failure, embolization, erosion risk profile (very thin atrial wall, oversized device). 

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5. Practical device-selection & sizing tips (interventionalist checklist)

1. Measure maximal ASD diameter in multiple planes (TEE/3D preferred). Choose device diameter typically 2–4 mm larger than maximal measured defect (centre-to-centre measurement varies by operator and device). 

2. Evaluate all rims individually — note any rim <5 mm, floppy tissue, or proximity to aorta/AV valves.

3. If aortic rim absent but other rims adequate, experienced operators may still implant device with cautious sizing and close follow-up; consider use of devices with lower profile and less risk of erosion. 

4. If multiple rim deficiencies (especially posteroinferior/IVC) — favour surgical consult; consider hybrid approaches (stent-assisted device anchoring) only in select centres with experience. 

5. Intra-procedural imaging (ICE or TEE) is essential to confirm seating, exclude impingement on valves or aorta, and check for residual shunt before release. 

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6. Outcomes & risks related to rim status

Meta-analyses and cohort studies show higher residual shunt and adverse events when important rims (posteroinferior/posterior) are deficient. Aortic rim deficiency alone does not universally preclude device closure and can often be managed successfully, though some increased device-related risks have been reported in certain series. Overall success and safety have improved with operator experience and device evolution. 

Device erosion/perforation is rare but linked to device oversizing and possibly to deficient anterosuperior (aortic) rim in some case series — avoid large degree of oversizing and ensure proper surveillance. 

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7. A practical stepwise algorithm (clinician-friendly)

1. Confirm ASD type — only secundum ASD considered for device closure. If primum, sinus venosus, coronary sinus → surgical. 

2. Initial imaging (TTE) — estimate size and rim presence. If good windows, proceed to TEE/3D or ICE for detailed planning. 

3. Measure maximal diameter and each rim (mm). Mark deficits (<5 mm), floppy tissue, multiple defects. 

4. Assess for associated lesions (PAPVR, valvular disease). If present → refer for surgical evaluation. 

5. If anatomy favorable (adequate rims, single defect, size suitable) → plan transcatheter closure with intra-procedural echocardiographic guidance. If marginal anatomy (one small rim but otherwise OK), discuss risks/benefits with patient and consider operator experience. 

6. If multiple significant rim deficiencies or extremely large defect → surgical closure or refer to tertiary centre for complex/interventional strategies. 

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8. Follow-up after closure

Early echo (24–48 h) to check device position and residual shunt; repeat at ~1–3 months and 6–12 months. Endocarditis prophylaxis per local guidelines until endothelialization (often 6 months) and antiplatelet therapy (aspirin ± clopidogrel) per institutional protocols. Monitor for late complications (device erosion, arrhythmia, residual shunt). 

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9. Emerging techniques & special cases

Large defects with deficient rims: in expert centres, hybrid approaches (covered stents, modified anchoring techniques) and newer devices allow closure of larger/complex defects that previously required surgery — but these are center- and operator-dependent and require careful case selection. 

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10. Practical pitfalls & pearls

Don’t rely on a single 2D plane. Use multiplane/3D imaging — rim width can be underestimated or overestimated in single views. 

Document rim quality, not just width. Floppy thin tissue behaves differently than firm tissue even if the measured mm value is similar. 

Informed consent must include the specific rim deficiencies and how they affect success rate and complication risks, including potential conversion to surgery.

If the anatomy is borderline, referral to a dedicated congenital/interventional centre is prudent.

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Key references (selected)

1. 2018 AHA/ACC Guideline for the Management of Adults With Congenital Heart Disease. 

2. Turner ME, et al. Transcatheter closure of atrial and ventricular septal defects (JACC review). 

3. Contreras AE, et al. Sufficient versus deficient rims during percutaneous ASD closure (meta-analysis, 2023). 

4. Fraisse A, et al. Atrial septal defect closure: indications and contraindications (J Thorac Dis review). 

5. ASE/ESC imaging and procedural guidance on ASD assessment (echo guidance & intraprocedural imaging). 

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Conclusion

Rim assessment is central to the decision between device vs surgical closure of secundum ASD. Use a structured imaging protocol (multiplane TEE/3D or ICE), measure maximal diameter and every rim, and integrate that anatomic data with patient factors, device availability, and local expertise. While many defects with isolated aortic rim deficiency can be safely closed percutaneously in experienced hands, deficiencies of posterior/posteroinferior rims, multiple rim deficits, very large defects, or associated structural lesions still favour surgical repair. Discuss borderline cases in multidisciplinary teams and involve experienced centers when complex techniques are being considered. 

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