Is Atrial Septal Defect (ASD) repair Magnetic Resonance Imaging (MRI) compatible?

MRI Compatibility of Atrial Septal Defect (ASD) Repair

Yes, both surgical and device-based ASD repairs are generally MRI compatible, though specific precautions may be needed depending on the type of repair.

Device-Based ASD Closure and MRI Compatibility

• The most commonly used ASD closure devices in the United States (AMPLATZER septal occluder and HELEX septal occluder) are composed of nitinol (nickel-titanium alloy), which is considered MRI compatible 1
• Cardiac MRI is rated as "May Be Appropriate" for routine surveillance after the first year following surgical ASD closure or PAPVC repair, indicating its safety for use in these patients 1
• In post-procedural evaluation of ASD device closure, CMR (Cardiovascular Magnetic Resonance) is rated as "Rarely Appropriate" within 30 days, not due to safety concerns but because other imaging modalities like TTE are preferred during this period 1

MRI's Role in ASD Patients

• MRI serves as an excellent non-invasive tool for diagnosis, planning, and follow-up after interventional ASD occlusion 2
• For evaluation due to change in clinical status or new concerning symptoms following ASD closure, CMR is rated as "Appropriate," indicating its safety and utility 1
• MRI shows excellent agreement with transesophageal echocardiography (TEE) for estimation of maximum defect size (R = 0.87) and can potentially replace TEE in the work-up for percutaneous closure 3

Specific Considerations for MRI After ASD Repair

• For patients with significant residual shunt, valvular or ventricular dysfunction, arrhythmias, or pulmonary hypertension following ASD closure, CMR is rated as "May Be Appropriate" for routine surveillance 1
• MRI has demonstrated significant improvement in right ventricular volumes, mass, and function after transcatheter closure of ASDs, making it valuable for follow-up assessment 4
• Cardiac MRI shows better correlation of ASD diameter measurement to balloon sizing compared to TEE, which is important for both pre-procedural planning and post-procedural assessment 5

Clinical Protocol for MRI After ASD Repair

• Wait at least 6 weeks after device implantation before performing MRI to allow for complete endothelialization of the device 6
• Standard MRI sequences can be used, including cine gradient echo, steady-state free precession sequences, and gradient echo phase contrast sequences 2
• MRI can accurately assess:
  • Device position and stability 6
  • Presence of residual shunting 6
  • Pulmonary-to-systemic flow ratio (Qp/Qs) 2
  • Right ventricular volumes and function 4

Precautions and Limitations

• While MRI is generally safe after ASD repair, patients should always inform radiology staff about their specific type of ASD closure device 6
• For routine surveillance within the first year following surgical ASD closure or PAPVC repair in asymptomatic patients, TTE is preferred over CMR 1
• In patients with device closure, CMR is rated as "Rarely Appropriate" for routine surveillance within the first week, at 1 month, at 3-6 months, and at 1 year, as TTE is the preferred modality during this period 1, 6

Conclusion

ASD repairs, whether surgical or device-based, are generally MRI compatible. The nitinol-based devices commonly used for ASD closure have been established as safe for MRI. Cardiac MRI serves as a valuable tool for both pre-procedural planning and post-procedural assessment of ASD repairs, particularly for evaluating right ventricular function and detecting complications.