The FDA alerted health care providers, particularly pediatric and adult cardiologists and surgeons, and patients that in very rare instances, tissue surrounding the St. Jude Amplatzer Atrial Septal Occluder (ASO) can erode and result in life-threatening emergencies that require immediate surgery. According to published estimates, these events occur in approximately 1 to 3 of every 1,000 patients implanted with the Amplatzer ASO. As of March 31, 2013, there have been 234,103 Amplatzer ASO devices sold worldwide.
The St. Jude Amplatzer Atrial Septal Occluder (ASO) is a cardiac implant device used in children and adults to treat an abnormal hole between the upper left and right chambers of the heart, known as an atrial septal defect (ASD). The metal device is put into place through catheter inserted into a vein. This is considered a minimally invasive method for ASD closure, and is an alternative to open heart surgery.
Tissue erosion caused by the Amplatzer ASO is rare, but can be life-threatening. Between 2002 and 2011, the FDA received more than 100 reports of erosions associated with the St. Jude Amplatzer ASO. During the same period, several medical journals contained articles reporting tissue erosion among patients implanted with this device.
The device rubbing against the wall of the heart can erode the tissue and create a hole. It can also lead to further scraping or erosion through tissue in the upper chambers of the heart, primarily in the top of the atria near the aorta. This scraping may also cause separate or simultaneous holes in the aortic root, potentially leading to blood building up in the sac surrounding the heart, known as cardiac tamponade. If too much blood builds up in this sac, the heart will not be able to work properly.
Immediate open heart surgery may then be necessary to remove the device, close the holes or other defects caused by erosion, and close the original defect the device was meant to treat less invasively. Tissue erosion can also cause fistulas, abnormal scar tissue that connects parts of the heart that were not previously connected. Fistulas are not life-threatening, but do require surgery for treatment and could result in congestive heart failure.
The FDA has not yet identified risk factors related to the occurrence of erosion. Articles in professional medical journals have discussed the possibility that patients with a lack of tissue in the retro-aortic rim might be at higher risk of erosion events. However, this relationship has not been determined. This type of device failure has not been seen in similar devices used to treat this condition.
The FDA recommended that physicians consider the potential for erosion when talking to patients about long- and short-term benefits and risks of treatment options, including implantation with the Amplatzer ASO. Doctors may inform patients that most people implanted with the Amplatzer ASO experience good outcomes and that erosion is a very rare event. Doctors should educate patients implanted with the Amplatzer ASO to seek immediate medical attention if they develop symptoms such as chest pain, numbness, sudden weakness, dizziness, fainting, shortness of breath, or rapid heartbeat.
The FDA did not recommend device removal for patients who have the Amplatzer ASO unless physicians determine it is appropriate for their particular patient(s). The risks associated with device removal surgery may be equal to or greater than the risk of erosion.
To better understand how erosion impacts the performance of the Amplatzer ASO and assess potential risk factors related to the occurrence of erosion, the FDA is requiring St. Jude to conduct a study of patients who have been recently implanted with the device. The study is designed to estimate the incidence of erosion events within seven days, one month, six months, and 12 months after the implantation of the Amplatzer ASO. The study will also compare patients who experience an erosion event to those who do not, and will identify differences in demographic, clinical, and device characteristics.
The FDA, medical device industry, and echocardiography societies are collaborating to develop standardized echocardiographic imaging techniques and guidelines for ASD procedures. These techniques and guidelines will provide needed information toward understanding pre-, peri-, and post-procedural anatomical characteristics of patients with atrial septal defects and the operation of the device in use.
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