Amplatzer Device: A Transcatheter Cardiac Occluder for Structural Heart Defects
The Amplatzer device is a self-expanding nitinol mesh occluder used for transcatheter closure of various cardiac defects, including atrial septal defects, ventricular septal defects, and patent ductus arteriosus, with high technical success rates and low complication profiles. 1
Device Structure and Characteristics
- Made from a Nitinol wire mesh (nickel-titanium alloy) shaped into two disks with a connecting waist
- The connecting waist centers the device in the defect while providing occlusion
- Self-expanding design allows for easy deployment and secure positioning
- Available in various configurations for different defect types:
Clinical Applications
1. Atrial Septal Defect (ASD) Closure
- Primary indication for secundum ASDs with suitable anatomy
- Technical success rate of 98% in clinical studies 3
- Complete occlusion achieved in approximately 90% of patients at 1-year follow-up 2
- Contraindicated for sinus venosus, coronary sinus, and primum defects (which require surgical closure) 4
2. Patent Foramen Ovale (PFO) Closure
- Used for patients with cryptogenic stroke attributed to paradoxical embolism
- May be considered for patients with recurrent stroke despite medical therapy
- Not routinely recommended for migraine with aura (insufficient evidence) 1, 5
3. Ventricular Septal Defect (VSD) Closure
- Used for muscular VSDs with suitable anatomy
- Perventricular hybrid approach may be used in small infants to avoid cardiopulmonary bypass 1
- Suitable for defects with:
- Hemodynamically significant shunt
- Low likelihood of spontaneous closure
- Accessible location without impingement on valves
- Adequate rim size for device stability 1
4. Patent Ductus Arteriosus (PDA) Closure
- Effective for PDAs of various sizes, including those up to 16mm
- High success rate with complete occlusion approaching 100% in long-term follow-up 1
Procedural Considerations
Anticoagulation Protocol
- Procedural anticoagulation: 100 U/kg UFH (up to 5000-U maximum dose) during implantation 1
- Post-procedural thromboprophylaxis:
- Low-dose aspirin for at least 6 months after implantation for all device types
- Additional anticoagulant may be considered for high-risk patients 1
Technical Aspects
- Typically performed under general anesthesia with transesophageal echocardiography guidance
- Device selection usually 1-2mm larger than the measured defect diameter
- Deployment involves:
Complications and Risks
Early Complications (0-30 days)
- Device embolization/migration (0.7%) 3
- Arrhythmias (1.8%) including atrial fibrillation 3
- Vascular access complications
- Procedural bleeding
Late Complications
- Cardiac erosion/perforation leading to tamponade
- Device thrombosis
- Residual shunting
- Recurrent embolic events (annual recurrence rate ~3.6%) 5
Follow-up Recommendations
- Echocardiography at 24 hours, 1 month, 6 months, and annually thereafter
- Continued antiplatelet therapy with low-dose aspirin for at least 6 months
- Annual clinical follow-up to monitor for:
- Residual shunting
- Device position
- Arrhythmias
- Ventricular function 4
Advantages Over Surgical Closure
- Avoids cardiopulmonary bypass
- Shorter hospital stay
- Reduced recovery time
- Less invasive with smaller incisions
- Lower overall complication rate for suitable defects 1, 4
The Amplatzer device has revolutionized the treatment of structural heart defects by providing a less invasive alternative to surgery with excellent outcomes. Patient selection and proper sizing of the device are critical factors for successful implantation and long-term results.