Contraindications to ASD Closure
ASD closure should not be performed when PA systolic pressure exceeds two-thirds of systemic pressure, pulmonary vascular resistance exceeds two-thirds of systemic resistance, or when there is a net right-to-left shunt. 1, 2
Absolute Contraindications (Class III: Harm)
The following represent situations where ASD closure causes harm and must be avoided:
- Severe pulmonary arterial hypertension with PA systolic pressure >2/3 systemic pressure
- Elevated pulmonary vascular resistance >2/3 systemic vascular resistance
- Net right-to-left shunting (Eisenmenger physiology)
These thresholds are consistently emphasized across both the 2018 AHA/ACC 1 and 2022 Canadian Cardiovascular Society 2 guidelines as absolute contraindications. Closure in these settings can precipitate acute right heart failure and clinical deterioration 3.
Relative Contraindications & Gray Zones
Borderline Pulmonary Hypertension (Class IIb)
ASD closure may be considered when:
- PA systolic pressure is 50-66% of systemic pressure, AND
- PVR is 1/3 to 2/3 of systemic resistance, AND
- Net shunt remains left-to-right
Critical caveat: These patients require assessment by a multidisciplinary team with expertise in both congenital heart disease and pulmonary arterial hypertension 2. The decision hinges on demonstrating preserved left-to-right shunting and excluding irreversible pulmonary vascular disease.
Complex Anatomical Scenarios
Contraindications based on anatomy and associated conditions:
ASD with complex congenital heart disease - Isolated ASD recommendations do not apply to defects associated with Ebstein anomaly, significant pulmonary stenosis, or right heart failure where the ASD may provide necessary decompression 1
Deficient rims or very large defects (>38mm) - While not absolute contraindications to closure, these are typically unsuitable for transcatheter approaches and require surgical evaluation 4, 5
Non-secundum defects - Primum ASDs, sinus venosus defects, and unroofed coronary sinus defects require surgical rather than transcatheter closure 2
Physiological Contraindications
Impaired left ventricular diastolic function deserves special attention. In elderly patients or those with diastolic dysfunction, acute closure can cause left atrial pressure to rise precipitously (potentially >25 mmHg), risking acute pulmonary edema 6. While not an absolute contraindication, this requires:
- Careful hemodynamic monitoring during test occlusion
- Readiness for mechanical ventilation and inotropic support
- Consider fenestrated devices in high-risk cases
Key Clinical Pitfalls
The most critical error is closing an ASD in unrecognized severe PAH. Pulse oximetry at rest AND with exercise is essential—some patients maintain oxygen saturation >90% at rest but desaturate to <90% with activity, revealing elevated pulmonary vascular resistance and shunt reversal 1.
Right heart catheterization is mandatory when pulmonary hypertension is suspected to accurately measure PA pressures and calculate PVR before making closure decisions 1, 2.
The guidelines differ slightly between AHA/ACC and ESC criteria for borderline cases, with ESC being more restrictive 7. When in doubt, err toward the more conservative ESC approach in borderline pulmonary hypertension cases.