The Degree of Inferior Vena Cava Filter Tilt Associated with Challenging Retrieval.

ABSTRACT

BACKGROUND: Inferior vena cava (IVC) filter tilt is associated with technical difficulties at the time of retrieval. However, the degree of tilt that predisposes patients to undergo complex or failed retrieval has not been defined. METHODS: The electronic charts of patients undergoing IVC filter removal between 2010 and 2019 at a single tertiary center were reviewed. Patient and procedural characteristics were recorded. Venograms of placement and retrieval procedures were reviewed, and IVC filter tilt was determined based on its deviation from the IVC axis. IVC diameter and the distance from the lowest renal vein were measured using corresponding filter's length for calibration. All measurements were performed by 3 reviewers and confirmed by 2 reviewers. Patients were divided into 2 groups those who underwent successful removal procedures requiring standard retrieval methods ("simple retrieval group") and those who required advanced endovascular techniques or had failed completely IVC filter retrievals ("challenging retrieval group"). A regression analysis was performed to determine factors associated with challenging retrieval. RESULTS: There were 365 patients who underwent IVC filter retrieval (n = 294 (80.6%) and n = 71 (19.4%) in the simple and challenging groups, respectively) with no difference in age, sex, comorbidities, or indication between the 2 groups. Failed retrieval occurred in 21 patients (5.8%) and was more common among patients requiring advanced endovascular techniques compared to standard techniques (18.0% vs. 3.2%, P < 0.001). In the overall cohort, the mean filter tilt at the time of retrieval was 4.9° ± 4.4° [0c27°], and 145 patients (39.7%) had a filter tilt ≥5.0°. Compared to the simple retrieval group, patients in the challenging group had significantly longer dwell time, greater tilt of IVC filter during placement and retrieval, as well as higher tilt change between the 2 venograms. There was no correlation between the access site during placement and challenging retrieval. However, patients undergoing filter placement via right jugular vein had lower filter tilt as compared to femoral access. Patients with filter tilt ≥5.0° were more likely to have a challenging filter retrieval compared to patients with ˂5.0° tilt (29.7% vs. 12.7%, P < 0.001). Regression analysis showed that tilt ≥5.0° (odds ratio [OR] = 1.18 [1.11-1.25]), dwell time (OR = 1.04 [1.01-1.07]), and age (OR = 0.97 [0.95-0.99]) were independently associated with challenging retrieval. CONCLUSIONS: IVC filter tilt ≥5.0°, dwell time and age are associated with challenging retrieval. Right jugular vein access, multiple imaging projections, and careful filter manipulation during deployment should be considered to maintain tilt at ˂ 5.0° and decrease the likelihood of challenging retrieval.