Radiofrequency wire-assisted recanalization of chronic venous stent occlusions

Abstract

Venous in-stent reocclusion can result in recurrent obstructive symptoms. Occlusions that are recalcitrant to traditional crossing techniques are inaccessible to effective therapies. However, radiofrequency-assisted recanalization techniques can mitigate the risk of therapy failure and allow treatment of previously untreatable lesions. The feature of automatic disabling of the radiofrequency wire upon metal contact can be exploited to increase the safety of crossing by ensuring intraluminal traversal and avoidance of unintended perforation of adjacent structures.

Keywords: In-stent restenosis; Radiofrequency; Venous stent.

Fig 1

Image of alert message displayed when radiofrequency (RF) wire contacts metal.

Fig 2

Case 1. Recanalization of chronically occluded iliofemoral vein stent. (A) Spot radiograph from prior recanalization attempt reveals previous thrombectomy attempts were unsuccessful due to inability to maintain intraluminal position at the level of the hip, and prior thrombectomy and angioplasty devices were deployed through the interstices and external to the stent lumen. (B) Left femoral venogram through mid-thigh left femoral vein access with 9 Fr sheath. (C) Spot radiograph demonstrating a 10-mm snare placed in the caudal most aspect of the stent. Right internal jugular access was achieved, and 8 Fr sheath was placed. A straight 75-g PowerWire was advanced from jugular approach through the in-stent occlusion, targeting the caudal 10-mm snare and avoiding the metal contact that would indicate stent exit through interstices. (D) Completion venogram following thrombectomy and stent relining of the caudal segment of the stent complex.

Fig 3

Case 2. Entry into the lumen of a bare metal stent using the radiofrequency (RF) wire. (A) Left arm venography demonstrates chronic occlusion of a stent extending from the superior vena cava to the left brachiocephalic vein as well as occlusion of peripheral segment of native left brachiocephalic vein. (B) Attempts at blunt recanalization failed to achieve entry into the left brachiocephalic vein. At the margins of the chronic occlusions, there is often a dense fibrous cap due to highly organized thrombus that are particularly resistant to blunt recanalization when they have a concave morphology. (C) The straight-tip 75-g RF PowerWire allowed traversal across the fibrous cap. After this, a hydrophilic guidewire was unable to be advanced into the stent because it repeatedly exited the intravascular space. (D) Using careful fluoroscopic triangulation, the angled tip catheter was pointed towards the orifice of the stent, and the PowerWire was used to successfully enter the occluded stent (E). (F) The angled catheter was used to follow the guidewire into the stent. (G) From here, a curved-tip Rosen guidewire was advanced through the stent. It is not uncommon for the thrombus within the stent to be less organized and fibrous than at the stent margins, sometimes allowing a buckled guidewire to be relatively quickly advanced without concern for exiting through stent interstices.

Fig 4

Case 3. Recanalization of a bare metal stent using the radiofrequency (RF) wire and angioplasty-assisted redirection. Patient with long-term chronic occlusion of right iliac vein stents and inferior vena cava (IVC). (A) Computed tomography venogram demonstrates chronic in-stent occlusion of the iliac veins and IVC to the level of an IVC filter, which is also notable for segments of calcified thrombus throughout. (B) Right iliac venogram demonstrates chronic occlusion of the stent with outflow via a dominant collateral vein. (C) Recanalization was performed from above, wherein blunt recanalization was successfully accomplished to the level of the right external iliac vein, at which point the guidewire repeatedly exited the vein. Attempts to reposition the angled catheter in a different direction to start a new tract failed, and further progress could not be made. (D) Angioplasty was performed with a 6-mm diameter angioplasty balloon to enlarge the tight, fixed space in which the catheter tip resided. (E) The newly created space allowed the angle of the catheter to express itself, allowing the catheter tip to point in a new direction towards the center of the stent. The straight-tip 75-g RF wire was able to be advanced in this new direction, creating a new tract that allowed additional blunt recanalization. (F) Successful traversal of the entirety of the occluded stent with a guidewire. Angioplasty and stenting were successful in restoring venous outflow to the right leg.

Fig 5

Case 4. Radiofrequency (RF)-guided recanalization after inadvertent jailing of central thoracic veins with covered stent. Patient with history of end-stage renal disease underwent right brachiocephalic-superior vena cava covered stent placement at an outside facility. (A) Venogram demonstrates that the stent graft was inadvertently deployed across the left brachiocephalic vein, resulting in acute thrombosis and ultimately chronic occlusion, leaving the patient with chronic left upper extremity venous outflow obstructive symptoms. (B) Spot radiograph after left basilic vein access with coaxial 8 and 6 Fr sheaths and left common femoral vein access. An 8-mm angioplasty balloon was inflated inside the right brachiocephalic vein stent graft to act as a target for the RF wire. Through the left brachiocephalic vein sheaths, Kumpe catheter was delivered, and using meticulous triangulation technique, the right-sided stent with balloon inside was targeted with a straight 75-g RF PowerWire. Initially, the wire deactivated with metal contact but was redirected caudally, along the undersurface of the stent graft, until the balloon was ruptured. (C) Completion venogram after balloon-expandable, covered stent graft reconstruction of the brachiocephalic vein confluence.

Fig 6

Case 5. Aborted recanalization of a transjugular intrahepatic portosystemic shunt (TIPS) stent. Patient with recurrently thrombosed TIPS stent presented for additional recanalization attempt. (A) Spot radiograph of radiofrequency (RF)-assisted recanalization attempts. After failed attempts to recanalize the stent using both traditional techniques, a snare was placed from a jugular vein approach. A straight-tip 75-g RF PowerWire was advanced from a transhepatic approach in an attempt to recanalize the stent. However, the wire continuously encountered metal contact despite attempts at redirection; this recurrent metal contact alert at the level of the deformed cephalad stent segment raised concern that recanalization would result in extraluminal wire passage and risk right atrial injury. Therefore, the procedure was aborted. (B) Venogram after patient returned for trans splenic-assisted percutaneous mesocaval shunt placement instead of TIPS recanalization, which has remained patent for >3 years at the time of this publication.