Original paper
Regaining venous access for implantation of a new lead

Introduction

Significant symptoms of venous occlusion or thrombosis in patients with a pacemaker or implantable cardioverter-defibrillator (ICD) are rarely observed in clinical practice. Most frequently, the diagnosis of occlusion is made accidently or during another procedure related to the implanted device, despite the fact that venous occlusion or its significant stenosis occurs in 10-25% of patients and clinical symptoms are present in 1-3% of cases [1, 2]. Prolongation of life and natural disease progression (especially the onset of heart failure) create a necessity to upgrade the existing pacemaker to an ICD or pacemaker/ICD with possibility of resynchronization (cardiac resynchronization therapy – CRT). In these situations it is necessary to insert a new electrode. Unfortunately, damage to the previously implanted electrode is becoming a more common indication for the procedure. Introduction of a new electrode into the venous system may be difficult due to venous occlusion (Figures 1 and 2). In that case of implantation ipsilateral to the previous one the following management strategies are possible: 1. Contralateral implantation of a new device (Figure 3).

2. Contralateral implantation of a new electrode and its percutaneous tunnelization to the previously created pacemaker implantation site (Figure 4).

3. Removal of a damaged or unnecessary lead and restoration of venous access.

The techniques listed in points 1 and 2 are subject to great inconvenience and potential risk of late complications re­sulting from the interaction between two implanted electronic devices, excess of remaining electrodes in the venous system and the need for creation of a percutaneous passage of electrodes. Therefore, the optimal procedure seems to consist of re­moval of the unnecessary electrode by means of special sets and, obtained this way, restoration of venous access.

Aim

The aim of the study was to assess the efficacy and safety of a new electrode implantation technique consisting of electrode removal and restoration of venous access.

Material and methods

The analysis included procedures of endocavitary electrode removal by means of transvenous technique performed between 1.08.2008 and 15.10.2012. Only the removal procedures for electrodes implanted  6 months earlier were chosen. Of the database including 203 patients, only procedures in which the main indication for removal was the need for implantation of a new electrode in spite of an existing ipsilateral venous occlusion were taken into consideration.



Procedure description



The procedures were performed in the operating theatre (and from January 2012 in a hybrid catheterization laboratory) with a possibility of immediate sternotomy and surgery with the use of extracorporeal circulation. Intratracheal general anaesthesia was used. There was continuous ECG, blood pressure, central venous pressure and oxygen saturation monitoring during the whole procedure. All elements of the procedures involving manoeuvres in the cardiovascular system were performed under fluoroscopy [3, 4]. Electrodes were dissected by means of an electric knife and their lumen was engaged with a standard guidewire. An attempt to unscrew the fixing element in case of active fixation electrodes was performed under fluoroscopy. If it was possible to use manual traction, an electrode stabilized with a guidewire covered with long sheath from the electrode extraction set was used. In all other cases a countertraction technique was applied. It is based on the use of a locking stylet (Liberator, COOK) and telescope Teflon or polypropylene sheaths (7-16 F). In case of failure to release the electrode from its adhesions, especially on its course in the subclavian or innominate vein, with the use of Teflon or polypropylene sheaths, mechanical traction by means of the COOK evolution set was applied. This technique was described in detail previously [5-8]. After removal of an unnecessary electrode the remaining sheath from the electrode extraction set was used to introduce a hemodynamic guidewire (0.8 mm, 150 cm length) into the right atrium. In situations where implantation of more than 1 electrode was needed an adequate number of guidewires was introduced. After removal of the extraction sheath the introduced guidewires were covered in a typical way with vascular peel-away sheaths (8-10 F, depending on the type of electrode). They were subsequently used to introduce new electrodes into the venous system. Electrodes were implanted according to the current standards with radiological control of their position and measurement of electrophysiological parameters. Then electrodes were connected to the device, which was placed in the implantation site. The wound was sutured in layers. After the procedure patients remained under observation in the intensive care unit. All procedures of electrode extraction were followed by echocardiographic and radiological (exclusion of pulmonary emphysema) examination.



Statistical analysis



Continuous variables were presented as arithmetic means ± standard deviations (SD) and categorical variables were depicted as percentages (%).

Results

During the analysed period a necessity to restore the vascular access was the main indication for the procedure in 10 pa­tients (4.9%). The need for implantation of a new electrode was related to: (1) electrode damage – 7 patients; (2) system upgrade (the use of resynchronization therapy) – 3 patients.

Patients’ clinical characteristics are presented in Table 1. Mean age of the patients was 59.5 ±21.4 years (14-80 years). In 5 patients only one electrode was removed. In 5 other cases it was necessary to extract more than 1 electrode. This was caused by malfunction of another electrode (n = 2), presence of the pacemaker on the other side of the body (n = 1), and dislocation or damage of an electrode during the procedure (n = 2). Altogether, 23 electrodes were extracted (9 defibrillation electrodes, 12 pacing electrodes and 2 left ventricular electrodes). Mean time from their implantation was 92.2 ±42.21 months (48-152 months). In the case of 20 electrodes, Teflon or polypropylene sheaths were used. Additional application of the Evolution system (except telescopic sheaths) was necessary for the extraction of three electrodes [4]. Manual traction (after previous extraction of a different electrode and restoration of venous access by means of telescopic sheaths) was enough for removal of three electrodes. Previously implanted, correctly functioning atrial electrodes were left in two cases. Detailed data presenting types of extracted electrodes, their age and the applied technique are presented in Table 2. In all cases it was possible to implant new electrodes as pre-planned. There were no serious complications in the analysed group (death, need for surgical intervention, pulmonary embolism, complications of anaesthesia, stroke or systemic infection).

Discussion

The study presented the management technique in case of venous occlusion in patients with previously implanted pacing or defibrillating electrodes, who require implantation of a new electrode. According to the current guidelines of the cardiological societies, class I indications for electrode extraction include bilateral subclavian vein or superior vena cava thrombosis in patients who require implantation of a new electrode. Class I indications also include situations when contralateral implantation is contraindicated (for example in patients after mastectomy or with the presence of a dialysis fistula). Restoration of venous access, if contralateral implantation is possible, was given a class II indication [3, 4]. There are not many studies on this subject in the literature [9-11]. It is difficult to assess in which percent of cases venous occlusion was the main indication for extraction of a previously implanted electrode. It is also impossible to find out how often alternative strategies are used (contralateral implantation or electrode tunnelization). There are also no data on the frequency of the use of other techniques for the system upgrade (for example, sewing of the left ventricular electrode with cardio-surgical methods) or how frequently the idea of system upgrade or the use of resynchronization therapy is abandoned. Venous occlusion is relatively frequent in patients with implanted endocavitary electrodes [1]. It is assumed that various degrees of stenosis are present in about 30% of patients. Due to asymptomatic course the diagnosis is made during system upgrade or removal of the damaged electrode. This has significant practical implications: venous patency on the side of the planned implantation should also be assessed before the procedure. Examinations shown to adequately assess the status of the venous system include venography and computed tomography. Ultrasonography does not permit one to assess the patency of the innominate vein or superior vena cava. It is important to remember that contrast administration through the antecubital vein may not demonstrate stenosis or occlusion of the superior vena cava. One of the methods of assessment consists of subclavian vein puncture and an attempt to introduce a 0.32-0.35 F guidewire to the right atrium (before preparation of the implantation site). Continuation of the procedure depends on the possibility to overcome the eventual occlusion and to introduce the guidewire beyond the occlusion site. Detection of the venous occlusion permits one to avoid unnecessary preparation of the implantation site, which is related to patient discomfort and increased risk of infection. It also allows one to plan another management strategy. Several laser techniques used to remove old electrodes and regain venous access have been described in the literature [9]. It was possible to restore venous access for im­plantation of new electrodes in all cases of 18 patients undergoing this type of procedure. An interesting, but rather controversial technique was described by Staniforth and Schilling [11]. It is based on removal of metallic parts of the electrode from the isolation followed by the introduction of a hemodynamic guidewire inside the isolation and electrode removal through the femoral vein. The guidewire remains in the right atrium, which permits the installation of a new sheath and electrode introduction. It should be noted that in almost 10% of cases (a total of 34 patients) it was impossible to fully remove the electrode. Released electrodes left in the vascular system are a source of potential complications related to electrode migration, arrhythmia generation or pulmonary embolism. In conclusion, it should be noted that implan- tation of a new electrode on the side of the previously installed device is possible despite venous occlusion. It should be expected that the number of patients with indications for this type of procedure will continue to grow. Such treatment, however, should be carried out with full cardio-surgical support, as the risk of serious complications associated with removal of the electrodes is 2-3%. It should also be noted that venous access restored after removal of the electrode is usually not permanent and that clinical signs of venous thrombosis occur quite often, which may be associated with endothelial damage in a large portion of the vein and with closure of collateral circulation [12].

Conclusions

The presence of venous occlusion should not be regarded as a contraindication to an upgrade of the existing system or to implantation of new electrodes on the side of the previously implanted device. Transvenous techniques of electrode removal permit venous access to be restored.

References

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