Successful endovascular treatment of Nutcracker and May-Thurner syndromes remains problematic because of possible stent migration. Although uncommon, the magnitude of the health risk imposed by this complication is great. There are several possible reasons for stent migration including the fluidity of the venous wall during the cardiac cycle. To prevent the stent embolization, we have employed the use of a temporary IVC filter to stabilize the immediately adjacent IVC wall and to trap a migrating stent. This study represents a retrospective analysis of prospectively collected data to identify any additional risk imposed by the use of an IVC filter in conjunction with venous stenting.

Pelvic venography was performed according to our protocol which mandates a 20° reverse Trendelenburg position, common femoral venous access, individual cannulation and imaging of bilateral renal, ovarian, common iliac, external iliac, and internal iliac veins, using only hand injection of contrast. Normal respiration during injection was permitted. IVUS was used to evaluate the left renal and left common iliac veins. Clinically significant venous compression was diagnosed only if all of the following conditions were met: the present of reflux, diversion of flow from major veins to smaller collateral veins, and cross pelvic venous flow. Women who had noncyclic pelvic pain for greater than 12 months, unremarkable gynecologic evaluations, and pelvic venography that documented the presence of clinically significant left renal or common iliac compression were considered candidates for treatment. Patients with venous compression, no matter how severe, but without evidence of these other venographic findings were not treated. All venograms were reviewed by a group consisting of vascular surgeons, interventional radiologists, and pelvic pain gynecologists. If the patient was considered a candidate for and consented to endovascular treatment of renal or iliac venous compression, a removable IVC filter was placed just above the planned proximal level of the stent as the initial step in the endovascular intervention. The stent, sized by IVUS, CT scan, and venogram was then placed. The patients were seen in follow-up at 3 weeks post-treatment. Between 4 - 6 weeks after stent placement the patient was reimaged and if there was no movement of the stent, the filter was removed. In 4 patients, the IVC diameter at the site of stent placement was measured across the respiratory cycle.

Of 190 patients evaluated, 33 were found to have clinically significant renal (22) or left common iliac compression (11). Endovascular treatment was undertaken in 10 patients with renal and in all 11 patients with iliac compression. All patients had successful placement of a removable IVC filter (Option, Argon Medical) from the right internal jugular approach for renal stents and right common femoral approach for the left common iliac stents. The presence of the filter did not interfere with stent placement (Wall, Vici, Boston Scientific). There were no complications from either portion of the procedure. All patients were discharged home on the day of the procedure. There were no 30 day complications. All patients complained of mild to moderate back discomfort described as a muscle ache or spasm in the vicinity of the IVC filter. This discomfort resolved almost immediately after stent removal in all cases. At the time of re-imaging, all stents were in the same position as the time of placement. There was no evidence of stent movement or malpositioning of filter body or tines. IVC filters were removed at a median of 4 weeks (3-24) after placement. There were no complications from filter removal. Respiratory variation in IVC diameter was 2mm (1.4-2.6mm) prior to filter placement across the respiratory cycle but undetectable after. After filter placement, no fluctuations in IVC diameter could be detected.

Temporary IVC filter placement is a simple and effective way of reducing the risk of stent migration, although the sample size of this study is inadequate for confirmation of treatment effect. There was no additional patient risk to filter placement and removal. It is likely that the filter may stabilize the IVC wall and reduce the fluctuations in IVC and target vein diameters, reducing vein wall movement around the stent to allow for more rapid stent incorporation.