Several teams of researchers have suggested that the possibility of migration may be “built in” to new-generation IVC filters.
While older models were made of stainless steel or titanium, new retrievable IVC filters come in a variety of cutting-edge alloys with “shape memory.” In colder temperatures, the filters become flexible. When heated, they return to their original shape. Thus fluctuations in body temperature can alter an IVC filter’s configuration, allowing it to detach from the vena cava and flow “upstream.”
Potential Complications Of Migration
In this 2009 report, cardiologists at Michigan’s William Beaumont Hospital described the case of a 54-year-old man whose retrievable IVC filter migrated from below his kidneys to the heart. Eventually, the device entered the patient’s right ventricle, one of the heart’s pumping chambers.
He suffered ventricular tachycardia, an abnormally rapid heart rate, and was subsequently diagnosed with non-Q-wave myocardial infarction, a less severe form of heart attack. A “percutaneous” solution, in which surgeons access internal organs through a single needle puncture, was proposed first but abandoned when it became clear that the IVC filter’s struts had become “intertwined” with tissues of a heart valve.
Ultimately, open-heart surgery was successful in removing the migrated IVC filter.
Symptoms Of Migration
Reviewing relevant medical publications between 1998 and 2008, the researchers found that a majority of patients in whom migration had occurred suffered immediate symptoms, including:
- chest pain,
- fainting (or “syncope) and
- abnormal heart rhythms.
Additionally, patients with migrated IVC filters were considered at high risk for serious complications like ventricular arrhythmia (a common precursor to heart attack) and cardiac tamponade, a potentially fatal medical emergency in which blood escapes into the gap between the heart muscle and the organ’s outer layer.