A 69–year–old man with a basal ganglia hemorrhage was found on his 9th hospital day to have multiple right upper and middle lobe pulmonary artery emboli (PE). Because of his recent hemorrhagic stroke, anticoagulation was contraindicated. The following day, an Optease IVC filter (composed of nitinol, a nickel–titanium alloy) was positioned in the infrarenal segment of the inferior vena cava (IVC) without complication. Seven days later, the abrupt onset of nonsustained ventricular tachycardia (NSVT) (up to 12 beats at a rate of 150 beats/min) was noted. Intravenous amiodarone was initiated without suppression and subsequent trans–thoracic echocardiogram (TTE) revealed embolization of the IVC filter to the right ventricle (RV) (Figure 1). Later that afternoon fluoroscopy confirmed device migration (Figure 2). The filter was eventually removed via use of a guidewire loop. Repeat TTE revealed new severe tricuspid regurgitation. Two days later an Eclipse IVC filter (also composed of nitinol) was placed in the infrarenal IVC. Eighteen months later the patient has had no recurrence of NSVT or PE and his tricuspid valve regurgitation is being clinically followed.
First used in 1972, IVC filters have become increasingly common in patients with contraindications to therapeutic anticoagulation. Prior to 2008, 98 intracardiac IVC filter migrations had been described, of which only 20 migrated as far as the right ventricle. More recently, device migration to the RV has become more common, probably due to changes in device construction. Earlier IVC filters were made of stainless steel or titanium, which were rigid and difficult to handle. Newer filters are constructed from lighter, more flexible alloys such as nitinol and elgioloy and have the ability to assume a unique shape when cooled below a certain temperature (facilitating insertion) and then regain their original shape when warmed to body temperature. These more flexible filters are easier to implant but appear more likely to migrate. In our patient we hypothesize that contact between the filter and the tricuspid valve, a notoriously arrhythmogenic area, caused recurrent NSVT unresponsive to intravenous amiodarone. NSVT promptly ceased with device extraction.
Although formerly rare, it is anticipated that IVC filter migration to the RV may become more frequent as filter construction continues to evolve. The abrupt development of frequent and complex ventricular ectopy, especially in individuals without known structural heart disease, should alert the clinician to the possibility of IVC filter migration, and should prompt noninvasive imaging.
Figure 1An apical 4 chamber view of a trans–thoracic echocardiogram showing the IVC filter (arrow) in the right ventricle. RA = right atrium, LA = left atrium and LV = left ventricle.
Figure 2Cardiac fluoroscopy, confirming the presence of the IVC filter (arrow) in the right ventricle.