Preserving Access After Lead Extraction in Venous Stenosis Using Snaring: The Cowboy Bridge Technique

Venous stenosis is a common challenge during device upgrade procedures, typically requiring either percutaneous crossing of the obstruction followed by venoplasty or lead extraction. The decision to perform an extraction in this setting must be carefully weighed up, as each approach offers distinct advantages; however, lead extraction is often favoured in many centres because of its ability to restore venous access and remove redundant leads.¹ It has also been associated with fewer complications when a generator replacement or system upgrade is planned, compared with lead-only extraction.² Notably, the Heart Rhythm Society Expert Consensus Statement on Cardiovascular Implantable Electronic Device Lead Management and Extraction supports this approach, designating lead extraction in patients with venous stenosis requiring an upgrade as a Class 2a indication.³

Maintaining continuous access to the right heart chambers during these procedures is essential, as both anterograde and retrograde crossing of the stenotic segment can be particularly difficult. This challenge may be intensified immediately following lead extraction, particularly if the extraction sheath does not easily progress beyond the stenosis site. Furthermore, a recently implanted lead may not offer enough support to keep advancing the extraction sheath.^4–6 The Cowboy Bridge technique emerges as a promising solution to this issue by using a retrograde snaring approach to maintain venous access even in the face of significant stenosis.

We discuss the successful application of this technique in two patients who required an upgrade from dual-chamber ICDs to CRT-defibrillators (CRT-D) and presented with occlusion of the ipsilateral venous access. By detailing the procedural steps and outcomes of the cases, we aim to illustrate the effectiveness of the Cowboy Bridge technique in overcoming access challenges posed by venous stenosis, advancing the field of cardiac device interventions and improving standards of patient care.

Case Report 1

A 78-year-old man with a medical history of hypertension, granulomatosis with polyangiitis and non-ischaemic cardiomyopathy, who had received an ICD for primary prevention 1 year earlier, was admitted due to newly diagnosed complete atrioventricular block requiring ventricular pacing. A transthoracic echocardiogram showed moderate-to-severe left ventricular dysfunction. Review of device telemetry showed that the patient had experienced multiple episodes of atrial flutter; thus, anticoagulation therapy was initiated. Given the deterioration of his functional capacity and the need for permanent ventricular pacing, the decision was made to upgrade his DF-4 ICD to a CRT-D. Pre-procedural upper-extremity peripheral venogram demonstrated complete occlusion of the left subclavian vein (Figure 1A). The plan was to obtain venous access through the removal of the right ventricular (RV) lead, followed by implantation of new right and left ventricular leads. The right atrial lead remained in its place.

Under general anaesthesia and guided by transoesophageal echocardiography, the patient was prepared in the operating room. In accordance with the local institution’s lead extraction protocols, bilateral femoral venous access was established with 7 Fr sheaths. A temporary pacing lead was placed via the right femoral vein into the RV to ensure stable pacing support throughout the procedure.

After making an incision over the existing subcutaneous pocket, the generator was carefully dissected free from its fibrotic adhesions and removed. The existing bipolar active fixation RV lead (Plexa ProMRI DF-4; Biotronik) was then prepared for extraction.

A locking stylet (Liberator, Cook Medical) was advanced to the RV lead tip, and upon gentle traction, the lead moved freely without significant resistance. A single 120 cm loop snare was introduced through the left femoral vein sheath and guided into the right atrium until the tip of the retracted lead was successfully captured (Figure 1B). Subsequently, the snared lead was carefully withdrawn through the superior vena cava, innominate vein and left subclavian vein to the device pocket, where the snare was released (Figures 1B–1D). Next, two guidewires for new ventricular lead placement were snared and pulled back into the right atrium by exerting traction from the proximal end of the snare in the left femoral access, thereby preserving venous access for the subsequent enhancement to CRT-D (Figures 1E–1). Angiography of the coronary sinus did not show any proper vessel to implant a lead. Finally, left bundle branch pacing was chosen as the pacing modality for CRT and a Rivacor 5 HF-T-QP (Biotronik) generator was placed in the subcutaneous pocket (Figure 1H).

Case Report 2

A 79-year-old man with a history of non-ischaemic cardiomyopathy, paroxysmal AF, left bundle branch block and a gastric ulcer who had received an ICD for primary prevention 5 years earlier, was admitted for elective upgrade to CRT-D because he remained symptomatic (New York Heart Association class II) with a left-ventricular ejection fraction of 25% despite optimal medical therapy.

Pre-procedural upper-extremity peripheral venogram confirmed complete occlusion of the left subclavian vein (Figure 2A). A 7 Fr sheath was placed in the right femoral vein.

A locking stylet (Liberator, Cook Medical) was advanced to the tip of the RV lead. Extraction of the lead was facilitated by mechanical dissection with an 11 Fr short rotating dilator sheath (Evolution Shortie RL, Cook Medical) followed by a 13 Fr long dilator sheath (Evolution RL, Cook Medical, Figure 2B). The tip of the retracted lead was then captured in the right atrium with a loop snare introduced via the femoral sheath, and the lead was extracted thorough the dilator sheath while right-atrial access was preserved (Figures 2C–2E). Two guidewires grasped by the snare were exteriorised from the original subclavian entry site, creating a ‘Cowboy Bridge’ rail (Figure 2F). Over this rail, a new RV pacing-defibrillation lead was positioned at the apical septum, and a quadripolar coronary-sinus lead was advanced to the distal posterolateral branch (Figure 2G). An Amvia Edge HF-T QP pulse generator (Biotronik) was placed in the existing pectoral pocket.

Discussion

The number of procedures involving the implantation of cardiac pacing devices has increased exponentially over recent decades. With the advancement of CRT, the number of endocavitary leads has likewise expanded, inevitably increasing the incidence of associated complications.⁷ In some cases, patients require an upgrade from simple pacing therapy to more complex resynchronisation therapy. A well-recognised obstacle during these upgrades is the selection of an appropriate vascular access route. It is estimated that up to 25% of patients with transvenous leads experience some degree of venous stenosis, which can complicate future lead implantation during system upgrades.⁸ Identified risk factors for venous stenosis include the presence of three or more leads and prior system revisions involving lead insertion.⁴ Notably, neither of the two patients in this series presented with known predictors of this complication.

Several strategies are available to address this issue, including tunnelling a new lead to the contralateral side of the chest, performing venoplasty or extracting the existing leads to create space for new leads. Currently, there is on-going debate regarding the optimal approach for patients who require an upgrade in the presence of ipsilateral venous stenosis.^1,9 Expert, high-volume centres typically prefer a complete transvenous extraction of previously implanted leads, thereby preserving the patency of the ipsilateral venous system and enabling device implantation on the same side.

Evidence suggests that when leads are left in place (i.e. abandoned) and a new system is implanted on the contralateral side, the rate of subsequent complications is significantly higher compared with cases where the primary venous route is maintained.¹⁰ Some of the reported drawbacks of this approach include lead-to-lead interactions, potential tricuspid valve damage, higher procedural complexity when performing future lead extractions and the traditional contraindication to MRI.^3,11 However, extracting the existing lead enables the creation of an access channel through the ipsilateral occluded vein, allowing for new lead implantation while preserving contralateral access for future interventions or as a bail-out option if the initial approach fails. Large registries have consistently demonstrated that transvenous lead extraction is a safe and effective procedure, with reported mortality rates between 0.2% and 1.2%.² Several studies have identified specific risk factors associated with procedural complications, including longer lead time duration (>6 years), female sex, low BMI, the presence of three or more implanted leads and infectious indications for extraction.² In our cases, none of these risk factors were present, which likely contributed to the favourable procedural outcomes.

Several anatomical and technical factors must be considered when selecting the most appropriate strategy. According to the study by Contractor et al., the obstruction can be approached antegradely, retrogradely, or through a combination of both methods.⁵ The antegrade approach offers an anatomical advantage, such as the direction of the valves and the manipulation of tools and catheters over short distances. Conversely, the retrograde approach often encounters less fibrotic tissue and reduced resistance. However, no randomised studies have clearly identified risk factors or predictive characteristics to guide the choice of one approach over another.

The Cowboy Bridge technique is a valuable addition to the armamentarium of cardiac electrophysiologists by preserving venous access after lead extraction in the setting of venous stenosis. One of the main advantages is that, in some cases, it may reduce the need for extraction tools and their associated complications. When an extraction sheath is required, the technique provides additional support for advancing the sheath once the leads are freed, while also lowering the risk of perforation compared to attempts at traversing the stenotic segment anterogradely or retrogradely with wires or catheters.

Our approach maintains the in-lead stylet throughout extraction, providing superior column strength and torque control compared with standard guidewires used in alternative techniques such as wire-under-the-insulation or retained-wire femoral strategies (Table 1).¹² This stiffness helps maintain lead integrity, improves coaxial support for subclavian-route extraction, and is especially valuable when the extraction sheath demonstrates kinking or when thrombus burden and longitudinal extent are uncertain on pre-procedural venography.

The technique remained feasible in older leads, as illustrated in Case 2. We decided to defer extracting the RV lead and later advance a wire through the extraction sheath as hyper-acute thrombotic occlusion can occur immediately after lead removal, potentially preventing antegrade wire passage. Pre-procedural venography can underestimate thrombus burden and longitudinal extent, especially in the left side, so removing the lead may be associated with a greater risk of wire loss. Additionally, fluoroscopy demonstrated sheath kinking, so keeping the lead distally engaged provided support to safely manipulate the extraction sheath.

Although retained wire femoral lead removal could also be an alternative in Case 2, our approach allows the femoral loop to secure several guidewires simultaneously and advance them to the right atrium/ventricle with a single traction. This reduces procedural steps and ensures immediate alternative support should one wire dislodge or prove insufficient for sheath delivery.

When no free lead end is available or the tip is entrapped, a femoral capture using a 94 cm Needle’s Eye Snare (Cook Medical) retrieval set remains compatible with the Cowboy Bridge technique. After the tip is released from the myocardium, temporary release and re-capture may be required to facilitate extraction from the axillary access.

The main limitation would be the rare scenario in which the freed lead is suddenly retracted from the cardiac chambers and becomes trapped within the stenosis segment, which impedes snaring the tip. Impingement of the snared lead in the venous stenosis is also a possible complication of this approach. In that circumstance, predefined bailouts include targeted venoplasty with ‘rendezvous’ wire externalisation to traverse the lesion, a jugular pull-through to recreate a superior rail when femoral reach is inadequate or contralateral implantation with subcutaneous tunnelling if ipsilateral recanalisation remains unsuccessful.

In our institution, all extraction procedures are performed in operating theatres or hybrid laboratories under strict sterile conditions. Although femoral snare-assisted techniques theoretically carry a risk of pocket contamination when instruments traverse from the groin to the subclavian region, this risk appears to be very low with full dual-field preparation, careful draping and standard peri-procedural antibiotic prophylaxis.

Venoplasty and stenting of the subclavian-innominate system occlusion were not considered as there is a high risk of repeated thrombosis due to the small diameter of these vessels; superior vena cava syndrome remains the most common indication for such interventions in our institution.⁵

We performed an in-depth description of the snaring technique suggested by Contractor et al.⁵ These case reports demonstrate the feasibility and efficacy of a retrograde snaring technique in enabling antegrade access during the challenges of device upgrade procedures. By implementing this strategy, we can mitigate the risks associated with venous occlusion and enhance the success rates of complex cardiac device interventions. This technique not only emphasises the critical nature of flexibility in procedural methodologies, but also offers a promising avenue for patients who require additional lead implantation following initial device upgrades.