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Inferior Vena Cava Filter Migration:‚ÄàUpdated Review and Case Presentation
ABSTRACT: We report a case of inferior vena cava filter migration to the right ventricle resulting in ventricular tachycardia and elevated troponin. The patient was taken to the cardiac catheterization laboratory and under fluoroscopy the filter was found to be in the right ventricle. Later in the day the filter was removed surgically with the aid of cardiopulmonary bypass. This case, as well as the other 27 reported cases of filter migration, were reviewed. It was noticed that newer retrievable filters made of nitinol, phynox and elgioly have a significantly higher percentage of filter migration into the right ventricle as compared to the old stainless steel and titanium-based Greenfield filters. Similarly, there were also higher percentages of complications and mortality associated with the newer retrievable filters migrating to the right ventricle. Filter migration to the right ventricle as opposed to the right atrium increased over the past 10 years, which has resulted in more serious symptoms, ventricular arrhythmias, deaths and higher rates of surgical removal.
J INVASIVE CARDIOL 2009;21:606–610
Key words: inferior vena cava filter migration, right ventricle filter migration, inferior vena cava filter removal
Case Presentation. We present the case of a 54-year-old morbidly obese male who was admitted to the hospital for laparoscopic gastric bypass surgery. Given his history of deep venous thrombosis (DVT) and pulmonary embolism (PE), he was deemed to be a high risk for DVT and PE recurrence, and thus in addition to adminstration of low-molecular-weight heparin, an inferior vena cava (IVC) filter was placed for perioperative PE prophylaxis. The IVC filter was placed at the level of L2 below the renal vein via a femoral approach under fluoroscopic guidance. Post-deployment venography was performed and spot fluoroscopic images were taken to confirm filter alignment, position and deployment. The following day, the patient underwent the laparoscopic Roux-en-Y gastric bypass surgery without any complication.
On postoperative day 2, he was found to have multiple premature ventricular contractions (PVCs) and a run of ventricular tachycardia (VT). He was completely asymptomatic at that time. Blood work was drawn and an electrocardiogram (ECG) was performed. The ECG revealed multiple PVCs and the only laboratory abnormality noted at that time was an elevated troponin level of 3.06. Consultation with the cardiologist resulted in a diagnosis of non-Q-wave myocardial infarction. The patient was started on intravenous heparin, aspirin, beta-blocker and clopidogrel.
He was taken to the cardiac catheterization laboratory. Prior to cardiac catheterization, fluoroscopy was performed due to the patient’s recent history of IVC filter placement. The IVC filter was noted to have migrated into the right ventricle (Figure 1). An echocardiogram was performed and showed that the IVC filter was located in the right ventricle (Figure 2). Percutaneous retrieval of the filter was not attempted because the filter hooks appeared to be intertwined with the chordae tendonae of the tricuspid valve, and the risk of valve damage was believed to be high. After discussion of the case with the cardiothoracic surgeon, the decision was made to proceed with surgical removal of the IVC filter from the right side of the heart under cardiopulmonary bypass. The right atrium was opened and the IVC filter was found in the right ventricle, caught in the chordate of the tricuspid valve. With special care, the filter was freed from the chordate and extracted without any structural damage to the heart (Figure 3). The patient tolerated the procedure well and was extubated the following day. He was discharged home after 1 week. No complications were noted at 1-year follow up.
Discussion. The use of IVC filters has been documented since 1973.1 Their use initially was limited to patients who developed venous thromboembolism (VTE) and also had contraindication to anticoagulation, or patients who were having recurrent VTE despite being on anticoagulation. With the advent of retrievable filters, their use has been extended for prevention of VTE in high-risk patients before they go for surgery. In our patient, the retrievable IVC filter was placed 1 day prior to laparoscopic gastric bypass surgery for PE prophylaxis. The potential indications for IVC filter use are documented in patients2 and listed in Table 1. Placement of a retrievable IVC filter in high-risk bariatric surgery appears to be safe and feasible, and offers potential clinical benefits to patient requiring short-term protection from PE.3 The use of an IVC filter as a prophylaxis for PE in bariatric surgery patients is becoming popular, even though there is no randomized clinical trial done to support this.
The uses for IVC filters have increased markedly during the last two decades. The number of patients who underwent IVC filter placement increased from 2,000 in 1979 to 49,000 in 1999.4 This increase in number also resulted in an increase in complications related to the IVC filter. IVC filter migration is an unusual, but potentially lethal, complication of filter placement. Filter migration to the heart can be avoided by a preinsertion cavogram, with measurement of the caval diameter for proper filter selection and the avoidance of insertion of any central venous line or pulmonary arterial catheter.5 But one shouldn’t forget that IVC is a dynamic vessel and caval sizing is only a two-dimensional image of the cava. Relying on this measure alone to gauge the presence or absence of mega cava may provide a misleading sense of security. Moreover, especially in bariatric surgery patients, the vena cava is under constant stress, especially from fluid resuscitation and dynamic stress of pneumoperitoneum and surgical manipulation intraoperatively.6 In addition to perioperative stress, an increase in abdominal pressure on the vena cava occurs in morbidly obese patients.7
Numerous cases of IVC filter migration to the right atrium and ventricle have been reported. In 1996, James et al reviewed 22 cases of Greenfield IVC filter migration to the heart, 15 of which migrated to the right atrium, 1 to the right ventricle, 3 to the right pulmonary artery and 1 to the left pulmonary artery. One death was recorded as being directly caused by the filter being attached to the myocardial wall.8 Although nearly half of these (10 of 22) have been asymptomatic, clinical manifestations of migration include arrhythmia and pericardial tamponade. Significant arrhythmia has been reported in 4 cases, one of which resulted in cardiopulmonary collapse. In 2004, Izutani et al reviewed 12 cases of IVC filter migration to the heart, 5 migrated to the right atrium, 5 to the right ventricle and 2 to the pulmonary artery.9 No IVC filter-related deaths were mentioned. Half of these patients (6 of 12) were asymptomatic. Clinical manifestations of migration include arrhythmia and cardiogenic shock and acute myocardial infarction (AMI).
We performed an electronic search using PubMed, which includes Medline, Old Medline and OVID. The dates of searches were from January 1998 to September 2008.We used combined medical subject-match headings (MeSH). The combined search terms were: inferior vena cava filter, which was matched with migration, displacement, migration to the heart, migration to the right atrium, migration to the right ventricle.
We included all the patients who had IVC filter migration to the heart or pulmonary arteries (Table 2). We also included the patients with a fractured filter arm migration to the heart. There were a total of 28 cases, including this case,6,9–33 out of which 10.7% (3/28 IVC filters, 95% CI 3.9–27.4%) of cases involved a broken filter arm migrating to the heart,11,14,19 and the remaining 89.3% (25/28 IVC filters, 95% CI 73.5–96.1%) involved IVC filters that migrated to the heart.6,9,10,12,13,15–18,20–33 The type of filter, site of migration, symptoms, treatment and outcome are shown in Table 2.
The goal of this review was to determine the differences in the presentation and outcome resulting from IVC filter migration as compared to the cases shown in previous reviews. It has been noticed that most of the patients who experienced IVC filter migration in the past 10 years had some symptoms (chest pain, palpitation, syncope and arrhythmias) (Table 2). They were also noted to be at increased risk for major cardiac events (ventricular arrhythmias and pericardial tamponade) and death as compared to the patients who had IVC filter migration shown in previous reviews (Table 3). The reason for this change in complication trends related to IVC filter migration to the heart is not known. At the same time, however, it has also been noticed that a higher percentage of the IVC filters migrated to the right ventricle.
The likely explanation for these cardiac symptoms and mortality rates may be due to increased filter migration beyond the tricuspid valve. James et al reported only 1 case of IVC filter migration to the right ventricle in patient who was experiencing multiple premature ventricular contractions.8 The filter was removed by cardiac surgery. Five patients reported by Izutani et al had right ventricle migration and 3 of whom were experiencing ventricular arrhythmia.9 Surgical removal was performed in all 3 of these patients. In the current review 60.7% (17/28 patients, 95% CI 42.3–76.5 %) of the patients either had a filter arm or the entire filter migrate to the right ventricle. Three of these patients died, and in 57% (8/14 patients CI 32.8–79.8%) of them, the filter was removed surgically. An overall comparison between percutaneous and surgical removal is provided in Table 4.
The newer IVC filters are made of lighter alloys, nitinol, phynox and elgioly (Table 5). These alloys are composed of different materials. They are radially compressible, axially flexible and self-expandable structures. The unique characteristic of these alloys is their thermally triggered shape memory. IVC filters that are constructed with such alloys can assume a different shape when cooled under a temperature transformational level. When the temperature rises above this level, these devices can regain their original shape. This allows the device to become soft at a lower temperature, which permits loading into a catheter in a relatively compressed and elongated state and regains the memorized shapes in an austenitic state when warmed to a selected temperature, above the temperature transformation level, such as human body temperature. Even in the austenitic state, these IVC filters are very flexible and readily conformable. The unique differences in the manufacturing materials could be the contributing factor to the higher incidence of IVC filter migration beyond the tricuspid valve compared to stainless steel or titanium-based IVC filters (Table 5). Migration beyond the tricuspid valve may result in a higher rate of surgical versus percutaneous removal.
Filter migration to the right ventricle as opposed to the right atrium has been noticed to increase in the past 10 years, resulting in more serious symptoms, ventricular arrhythmias, deaths and a higher rate of surgical removal.
