Fragment embolization rates high for Bard vena cava filters
MedWire News: Bard retrievable vena cava filters have a high prevalence of fracture and embolization, with potentially life threatening consequences, US researchers report.
"Vena cava filters represent an alternative treatment option for patients with contraindications to anticoagulation, or they might serve as adjunctive treatment for continued emboli despite anticoagulation," explain William Nicholson (York Hospital, York, Pennsylvania) and colleagues.
"The fracture of a filter strut with subsequent end-organ embolization is a rarely reported but potentially life-threatening occurrence," they add.
Following an initial case of filter fracture at their hospital, Nicholson and team evaluated 80 patients who received either a Bard Recovery (first generation) or a Bard G2 (second generation) vena cava filter between April 2004 and January 2009. The patients underwent fluoroscopy to assess the integrity of the filter. Those whose filter was fragmented also underwent echocardiography and cardiac computed tomography.
The researchers found that 13 (16%) patients had at least one strut fracture from their filter. This included seven (25%) of 28 patients with Bard Recovery filters. In five (71%) of these seven cases, at least one fragment embolized to the heart. Three patients experienced life-threatening symptoms of ventricular tachycardia and/or tamponade, and one patient experienced sudden death at home.
The Bard G2 filter had a lower, but still high, fracture prevalence of 12% (six of 52 patients). In two of these six cases, the patients had asymptomatic end-organ fragment embolization to the hepatic vein and lung. In the remaining four patients, the fragments stayed close to the filter.
Nicholson and team note that the average time since filter implantation was about 50 months for patients with the Bard Recovery filter and 24 months for the Bard G2 filter. They suggest that the prevalence of Bard G2 filter fractures would be higher if they had been in place for a similar amount of time as the Bard Recovery filter.
"It is essential that patients and their treating physicians be educated about this previously underrecognized and potentially life-threatening complication of these devices," write Nicholson and team in the Archive of Internal Medicine
"Early awareness and evaluation could be life saving," they conclude.
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By Laura Dean