Long-term thrombosis after transvenous permanent pacemaker implantation

Pulmonary Thromboembolism and Myocarditis Resulting from a Large Pacing-Lead-Associated Right Ventricular Thrombus in a Dog with Chronic Cough as Presenting Sign

In the present case report, we describe the clinical course and postmortem findings of a 12-year-old Labrador retriever dog with a third-degree atrio-ventricular block that developed a chronic cough, and later dyspnea and weakness as a result of massive pulmonary thromboembolism 3 years after implantation of a transvenous permanent pacemaker. A large soft tissue mass was seen in the right ventricular chamber around the pacing lead with echocardiography. Initially, this was thought to be caused by mural bacterial endocarditis based on hyperthermia, severe leukocytosis and the appearance of runs of ventricular tachycardia, the latter suggesting myocardial damage. While blood culture results were pending, antibiotics were administered without a positive effect. Due to clinical deterioration, the owner elected for euthanasia and a post-mortem examination confirmed a right ventricular thrombus and surrounding myocarditis, without signs of bacterial infection, and a massive pulmonary thromboembolism. We conclude that pulmonary thromboembolism should be considered in dogs with a cough that have an endocardial pacing lead implanted. Serial screening for proteinuria before and after implantation of an endocardial pacing lead would allow timely initiation of prophylactic antiplatelet therapy. Local myocarditis can develop secondary to an intracavitary thrombus, which can subsequently lead to runs of ventricular tachycardia.

Multilevel Venous Obstruction in Patients with Cardiac Implantable Electronic Devices

Background and Objectives: The nature of multilevel lead-related venous stenosis/occlusion (MLVSO) and its influence on transvenous lead extraction (TLE) as well as long-term survival remains poorly understood. Materials and Methods: A total of 3002 venograms obtained before a TLE were analyzed to identify the risk factors for MLVSO, as well as the procedure effectiveness and long-term survival. Results: An older patient age at the first system implantation (OR = 1.015; p < 0.001), the number of leads in the heart (OR = 1.556; p < 0.001), the placement of the coronary sinus (CS) lead (OR = 1.270; p = 0.027), leads on both sides of the chest (OR = 7.203; p < 0.001), and a previous device upgrade or downgrade with lead abandonment (OR = 2.298; p < 0.001) were the strongest predictors of MLVSO. Conclusions: The presence of MLVSO predisposes patients with cardiac implantable electronic devices (CIED) to the development of infectious complications. Patients with multiple narrowed veins are likely to undergo longer and more complex procedures with complications, and the rates of clinical and procedural success are lower in this group. Long-term survival after a TLE is similar in patients with MLVSO and those without venous obstruction. MLVSO probably better depicts the severity of global venous obstruction than the degree of vein narrowing at only one point.

Pacemaker-lead-associated thrombosis in dogs: a multicenter retrospective study

INTRODUCTION

Pacemaker implantation is the treatment of choice for clinically relevant bradyarrhythmias. Pacemaker-lead-associated thrombosis (PLAT) occurs in 23.0-45.0% of people with permanent transvenous pacemakers. Serious thromboembolic complications are reported in 0.6-3.5%. The incidence of PLAT in dogs is unknown.

ANIMALS, MATERIALS AND METHODS

multicenter retrospective study of seven centers with 606 client-owned dogs undergoing permanent pacemaker implantation between 2012 and 2019. 260 dogs with a transvenous pacemaker with echocardiographic follow-up, 268 dogs with a transvenous pacemaker without echocardiographic follow-up and 78 dogs with an epicardial pacemaker.

RESULTS

10.4% (27/260) of dogs with transvenous pacemakers and echocardiographic follow-up had PLAT identified. The median time to diagnosis was 175 days (6-1853 days). Pacemaker-lead-associated thrombosis was an incidental finding in 15/27 (55.6%) dogs. Of dogs with a urine protein:creatinine ratio measured at pacemaker implantation, dogs with PLAT were more likely to have proteinuria at pacemaker implantation vs. dogs without PLAT (6/6 (100.0%) vs. 21/52 (40.4%), P=0.007). Urine protein:creatinine ratio was measured in 12/27 (44.4%) dogs at PLAT diagnosis, with proteinuria identified in 10/12 (83.3%) dogs. Anti-thrombotic drugs were used following the identification of PLAT in 22/27 (81.5%) dogs. The thrombus resolved in 9/15 (60.0%) dogs in which follow-up echocardiography was performed. Dogs with PLAT had shorter survival times from implantation compared to those without PLAT (677 days [9-1988 days] vs. 1105 days [1-2661 days], P=0.003).

CONCLUSIONS

Pacemaker-lead-associated thrombosis is identified in 10.4% (27/260) of dogs following transvenous pacing, is associated with proteinuria, can cause significant morbidity, and is associated with reduced survival times.

Severity and Extent of Lead-Related Venous Obstruction in More Than 3000 Patients Undergoing Transvenous Lead Extraction

Background

Lead-related venous stenosis/obstruction (LRVSO) may be a major challenge in patients with cardiac implantable electronic devices (CIED) when device upgrade, insertion of central lines, or creation of an arteriovenous fistula for hemodialysis is indicated. The aim of this study was to evaluate the extent and severity of LRVSO.

Methods

We performed a retrospective analysis of 3002 venograms from patients awaiting transvenous lead extraction (TLE) to assess the occurrence, severity, and extent of LRVSO.

Results

Mild LRVSO occurred in 19.9%, moderate in 20.7%, severe in 19.9% and total venous occlusion in 22.5% of the patients. Moderate/severe stenosis or total occlusion of the subclavian and brachiocephalic veins was found in 38.2% and 22.5% of the patients, respectively. LRSVO was not detected in 16.9% of the patients. Moderate and severe superior vena cava (SVC) obstruction and total SVC occlusion were rare (0.4%, 0.3%, and 0.3%, respectively). Lead insertion on the left side of the chest contributed to an increased risk of LRVSO compared to right-sided implantation. Major thoracic veins on the opposite side may be narrowed in varying degrees.

Conclusion

A total of 60% of the patients with pacemaker or high-voltage leads have an advanced form of LRVSO. Any attempt to insert new pacing leads, central lines, venous ports, or catheters for hemodialysis, or to create dialysis fistula on the same side as the existing lead should be preceded by venography. Furthermore, venography may provide useful information, if it is planned to implant the lead or the catheter on the opposite side of the chest.

The Role of Preoperative Venography in Predicting the Difficulty of a Transvenous Lead Extraction Procedure

INTRODUCTION

We hypothesized that an accurate assessment of preoperative venography could be useful in predicting transvenous lead extraction (TLE) difficulty.

METHODS AND RESULTS

A dedicated preoperative venogram was performed in consecutive patients with cardiac implantable electronic device who underwent TLE. The level of stenosis was classified as without significant stenosis, moderate, severe, and occlusion. The presence of extensive lead-venous wall adherence (≥50 mm) was also assessed. A total of 105 patients (median age 71 years; 72% male) with a median of 2(1-2) leads to extract were enrolled. Preoperative venography showed moderate to severe stenosis in 31(30%), complete occlusion in 15(14%), and extensive lead-venous wall adherence in 50 (48%) patients. Complete TLE success was achieved in 103(98%) patients. Fifty-five (52%) were advanced extractions as they required a power mechanical and/or laser sheath. They were more prevalent in the group with extensive lead-venous wall adherence (72% vs. 34%, p<0.001), while no differences were found between patients with and without venous occlusion. In multivariate analysis, the presence of adherence was a predictor of advanced extraction (odds ratio 2.89[1.14-7.32], p=0.025). The fluoroscopy time was also significantly longer (14.0[8.2-18.7] vs. 5.1[2.1-10.0] min, p<0.001). The rate of complications did not differ based on the presence of venous lesions.

CONCLUSION

Although procedural success and complication rates were similar, patients with extensive lead-venous wall adherence required a longer fluoroscopy time and were 3 times more likely to need advanced extraction tools. Conversely, the presence of total venous occlusion had no impact on the procedure complexity. This article is protected by copyright. All rights reserved.

New Insights in Central Venous Disorders. The Role of Transvenous Lead Extractions

Over the last decades, the implementation of new technology in cardiac pacemakers and defibrillators as well as the increasing life expectancy have been associated with a higher incidence of transvenous lead complications over time. Variable degrees of venous stenosis at the level of the subclavian vein, the innominate trunk and the superior vena cava are reported in up to 50% of implanted patients. Importantly, the number of implanted leads seems to be the main risk factor for such complications. Extraction of abandoned or dysfunctional leads is a potential solution to overcome venous stenosis in case of device upgrades requiring additional leads, but also, in addition to venous angioplasty and stenting, to reduce symptoms related to the venous stenosis itself, i.e., the superior vena cava syndrome. This review explores the role of transvenous lead extraction procedures as therapeutical option in case of central venous disorders related to transvenous cardiac leads. We also describe the different extraction techniques available and other clinical indications for lead extractions such as lead infections. Finally, we discuss the alternative therapeutic options for cardiac stimulation or defibrillation in case of chronic venous occlusions that preclude the implant of conventional transvenous cardiac devices.

Soft Bioelectronics Based on Nanomaterials

Recent advances in nanostructured materials and unconventional device designs have transformed the bioelectronics from a rigid and bulky form into a soft and ultrathin form and brought enormous advantages to the bioelectronics. For example, mechanical deformability of the soft bioelectronics and thus its conformal contact onto soft curved organs such as brain, heart, and skin have allowed researchers to measure high-quality biosignals, deliver real-time feedback treatments, and lower long-term side-effects in vivo. Here, we review various materials, fabrication methods, and device strategies for flexible and stretchable electronics, especially focusing on soft biointegrated electronics using nanomaterials and their composites. First, we summarize top-down material processing and bottom-up synthesis methods of various nanomaterials. Next, we discuss state-of-the-art technologies for intrinsically stretchable nanocomposites composed of nanostructured materials incorporated in elastomers or hydrogels. We also briefly discuss unconventional device design strategies for soft bioelectronics. Then individual device components for soft bioelectronics, such as biosensing, data storage, display, therapeutic stimulation, and power supply devices, are introduced. Afterward, representative application examples of the soft bioelectronics are described. A brief summary with a discussion on remaining challenges concludes the review.

Risk Factors for Lead-Related Venous Obstruction: A Study of 2909 Candidates for Lead Extraction

Background: our knowledge of lead-related venous stenosis/occlusion (LRVSO) remains limited and there is still controversy regarding the risk factors for LRVSO. Venography is mandatory before transvenous lead extraction (TLE). Methods: we performed a retrospective analysis of venograms in 2909 patients (39.43% females, average age 66.90 years) who underwent TLE between 2008 and 2021 at high-volume centers. Results: the severity of LRVSO was likely to be dependent on the number of leads in the system (OR = 1.345; p = 0.003), the number of abandoned leads (OR = 1.965; p < 0.001), the presence of coronary sinus leads (OR = 1.184; p = 0.056), male gender (OR = 1.349; p = 0.003) and patient age at first CIED implantation (OR = 1.008; p = 0.021). The presence of permanent atrial fibrillation (OR = 0.666; p < 0.001) and right ventricular diastolic diameter (OR = 0.978; p = 0.006) showed an inverse correlation with the degree of LRVSO. The combined three-model multivariate analysis provided better prediction of LRSVO using the above-mentioned factors than the CHA2DS2-VASc score. Conclusions: the severity of LRVSO is probably dependent on the mechanical impact of the implanted/abandoned leads on the vein wall, therefore the study has demonstrated the central role of system-/procedure-related risk factors. The thrombotic mechanism may be less important, especially long after implantation, and for this reason the combined prediction model for LRVSO in this study was more effective than the CHA2DS2-VASc score.

The Influence of Lead-Related Venous Obstruction on the Complexity and Outcomes of Transvenous Lead Extraction

Background: Little is known about lead-related venous stenosis/occlusion (LRVSO), and the influence of LRVSO on the complexity and outcomes of transvenous lead extraction (TLE) is debated in the literature. Methods: We performed a retrospective analysis of venograms from 2909 patients who underwent TLE between 2008 and 2021 at a high-volume center. Results: Advanced LRVSO was more common in elderly men with a high Charlson comorbidity index. Procedure duration, extraction of superfluous leads, occurrence of any technical difficulty, lead-to-lead binding, fracture of the lead being extracted, need to use alternative approach and lasso catheters or metal sheaths were found to be associated with LRVSO. The presence of LRVSO had no impact on the number of major complications including TLE-related tricuspid valve damage. The achievement of complete procedural or clinical success did not depend on the presence of LRVSO. Long-term mortality, in contrast to periprocedural and short-term mortality, was significantly worse in the groups with LRSVO. Conclusions: LRVSO can be considered as an additional TLE-related risk factor. The effect of LRVSO on major complications including periprocedural mortality and on short-term mortality has not been established. However, LRVSO has been associated with poor long-term survival.

Upper Extremity Deep Vein Thrombosis and Asymptomatic Vein Occlusion in Patients With Transvenous Leads: A Systematic Review and Meta-Analysis

Aims: The presence of transvenous leads for cardiac device therapy may increase the risk of venous thromboembolisms. The epidemiology of these complications has not yet been determined systematically. Therefore, this study aims to determine (I) the incidence of symptomatic upper extremity deep vein thrombosis (UEDVT) and (II) the prevalence of asymptomatic upper extremity vein occlusion in patients with transvenous leads, both after the initial 2 months following lead implantation.

Methods: PubMed, EMBASE, and Cochrane Library were searched until March 31, 2020 to identify studies reporting incidence of UEDVT and prevalence of asymptomatic vein occlusion after the initial 2 months after implantation in adult patients with transvenous leads. Incidence per 100 patient years of follow-up (PY) and proportions (%) were calculated to derive pooled estimates of incidence and prevalence.

Results: Search and selection yielded 20 and 24 studies reporting on UEDVT and asymptomatic vein occlusion, respectively. The overall pooled incidence of UEDVT was 0.9 (95% CI 0.5–1.4) per 100PY after 2 months after lead implantation. High statistical heterogeneity was present among studies (I² = 82.4%; P = < 0.001) and only three studies considered to be at low risk of bias. The overall pooled prevalence of asymptomatic upper extremity vein occlusion was 8.6% (95% CI 6.0–11.5) with high heterogeneity (I² = 81.4%; P = <0.001). Meta-regression analysis showed more leads to be associated with a higher risk of UEDVT.

Conclusion: Transvenous leads are an important risk factor for symptomatic UEDVT, which may occur up to multiple years after initial lead implantation. Existing data on UEDVT after lead implantation is mostly of poor quality, which emphasizes the need for high quality prospective research. Asymptomatic vein occlusion is present in a substantial proportion of patients and may complicate any future lead addition.

Clinical Trial Registration: (URL: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020178136, Identifier: PROSPERO 2020 CRD42020178136).

Permanent pacemaker implantation in a hemodialysis patient with subclavian vein occlusion using the balloon-target puncture technique

The balloon-target puncture technique is an effective method to secure the subclavian vein access route of cardiovascular implantable electronic devices.

Alternate method for endocardial pacemaker lead implantation: A hybrid mini-thoracotomy approach

Although the conventional methods for endo-cardial pacemaker lead implantation via subclavian or cephalic or axillary vein routes is common, but sometimes due to anatomical variations it is not feasible to access these veins Emergence of newer techniques are useful for lead implantation. This case report focuses on a hybrid approach of combined mini-thoracotomy for endocardial pacemaker lead implantation. This fluoroscopy guided minimal thoracotomy approach with endocardial MRI compatible lead placement had the benefits of simple procedural, minimal hospital stay, low early complication rates and economically viable to the patient.

Endovascular Neuromodulation: Safety Profile and Future Directions

Endovascular neuromodulation is an emerging technology that represents a synthesis between interventional neurology and neural engineering. The prototypical endovascular neural interface is the Stentrode^TM, a stent-electrode array which can be implanted into the superior sagittal sinus via percutaneous catheter venography, and transmits signals through a transvenous lead to a receiver located subcutaneously in the chest. Whilst the Stentrode^TM has been conceptually validated in ovine models, questions remain about the long term viability and safety of this device in human recipients. Although technical precedence for venous sinus stenting already exists in the setting of idiopathic intracranial hypertension, long term implantation of a lead within the intracranial veins has never been previously achieved. Contrastingly, transvenous leads have been successfully employed for decades in the setting of implantable cardiac pacemakers and defibrillators. In the current absence of human data on the Stentrode^TM, the literature on these structurally comparable devices provides valuable lessons that can be translated to the setting of endovascular neuromodulation. This review will explore this literature in order to understand the potential risks of the Stentrode^TM and define avenues where further research and development are necessary in order to optimize this device for human application.

Modified Pull-Through Technique for Cardiac Resynchronization Therapy Upgrades in Patients with Occluded Access Veins

The number of procedures for upgrading implantable devices for cardiac resynchronization therapy has increased considerably during the last decade. A major challenge that operators face in these circumstances is occlusion of the access vein. We have modified a pull-through method to overcome this obstacle. Six consecutive patients with occluded access veins and well-developed collateral networks underwent a procedure in which the occluded vein was recanalized by snaring the existing atrial lead via transfemoral access. Upgrading the device was successful in all patients; none had intraprocedural complications. Our experience shows that our modified pull-through technique may be a feasible alternative for upgrading cardiac resynchronization therapy in patients with venous occlusion.

Predictors of venous stenosis or occlusion following first transvenous cardiac device implantation: Prospective observational study

INTRODUCTION

Venous stenosis or occlusion related to an intracardiac device is a well-known complication of that procedure. There are numerous studies tried to determine predictors of venous stenosis or occlusion; however, most of them investigate the venous system prior to device upgrade, generator replacement, or transvenous lead extraction. Therefore, we aimed to assess the prevalence and determine the predictors of venous stenosis or occlusion following first transevnous cardiac device implantation.

METHODS

Observational, prospective study included 71 consecutive patients admitted for first transvenous cardiac device implantation. All patients were followed up for 6 months after operation.

RESULTS

Implanted device systems comprised cardioverter defibrillator (n = 26), single-chamber or dual-chamber pacemakers (n = 34), and biventricular pacemakers (n = 11); 88.5% of implantable cardioverter defibrillator leads were single-coils and 11.5% were dual-coils. The incidence of venous stenosis or occlusion within 6-month follow-up was 21.1%. Multivariate logistic regression showed that only diabetes or prediabetes (p = 0.033, odds ratio: 0.17, 95% confidence interval: 0.04-0.87), prolonged procedure time (p = 0.046, odds ratio: 4.54, 95% confidence interval: 1.01-20.12), and perioperative complications (p = 0.021, odds ratio: 7.04, 95% confidence interval: 1.35-36.85) were predictors of venous stenosis or occlusion.

CONCLUSION

Prolonged implantation time (>60 min) and perioperative complications are associated with an increased risk of venous stenosis or occlusion, whereas diabetes and prediabetes significantly reduce the risk of venous stenosis or occlusion.

Arteriovenous Fistula and Graft Construction in Patients with Implantable Cardiac Devices: Does Side Matter?

BACKGROUND

Limited reports have documented the effect cardiac implantable electronic devices (CIEDs) have on arteriovenous (AV) access patency. Current recommendations suggest placing the access on the contralateral side of the CIEDs, as there is concern for increased central venous stenosis and access failure. The goal of this study is to review our single-center AV access patency rates for dialysis patients with an ipsilateral or contralateral side CIED.

METHODS

A retrospective review was performed from 2008 to 2016 at a single institution identifying all patients who have received a CIED and the diagnosis of end-stage renal disease (ESRD). Medical records were queried to identify each patient's dialysis access and whether it was ipsilateral or contralateral to the CIED. Primary outcomes of study were primary and secondary patency rates.

RESULTS

A total of 44 patients were identified to have ESRD and CIED. Of these patients, 28 patients with fistulas or grafts (13 ipsilateral and 15 contralateral) had follow-up with regards to their AV access. There were 3 primary failures in both groups. For patients who had the CIED placed after already starting the dialysis, patency was based on when the cardiac device was implanted. Primary patency for ipsilateral and contralateral access was 20.2 and 22.2 months, respectively. With secondary interventions, ipsilateral and contralateral mean patency was 39 and 48.8 months, respectively. Six-month and 1-year primary patency for arteriovenous fistula or arteriovenous graft on patients with ipsilateral access was 69.2% and 53.8%, respectively. Ipsilateral 1-year cumulative patency was 39 months.

CONCLUSIONS

CIED may lead to stenosis or occlusion to one's AV access; however, primary assisted and secondary patency rates are still acceptable at 6 months and 1 year compared to Kidney Disease Outcomes Quality Initiative guidelines. Despite a CIED, a surgeon's algorithm should not lead to the abandonment of an ipsilateral access if the central venous system is patent.

Venous Obstruction in Cardiac Rhythm Device Therapy

PURPOSE OF REVIEW

A variety of complex vascular pathologies arise following the implantation of electronic cardiac devices. Pacemaker and defibrillator lead insertion may cause proximal venous obstruction, resulting in symptomatic venous congestion and the compromise of potential future access sites for cardiac rhythm lead management.

RECENT FINDINGS

Various innovative techniques to recanalize the vein and establish alternate venous access have been pioneered over the past few years. A collaborative team of electrophysiologists and vascular specialists strategically integrate the patient's vascular disease into the planning of electrophysiology procedures. When vascular complications occur after device implantation, the same team effectively manages both the resulting vascular sequelae and related cardiac rhythm device challenges. This review will outline the various vascular challenges related to device therapy and offer an effective strategy for their management.

Venous System Interventions for Device Implantation

Subclavian obstruction is common after lead implantation and the need to add or replace a lead is increasing. Subclavian venoplasty (SV) is a safe and effective option for venous occlusion. Peripheral venography overestimates the severity of the obstruction. A wire can usually be advanced into the central circulation for SV. Compared with dilators, SV improves the quality of venous access, providing unrestricted catheter manipulation for His bundle pacing and left ventricular lead implantation. SV preserves venous access and reduces lead burden. SV can easily be added to the implanting physicians lead management options.

Novel experience of laser-assisted 'inside-out' central venous access in a patient with bilateral subclavian vein occlusion requiring pacemaker implantation

Aim

This new laser facilitated 'inside-out' technique was used for transvenous pacemaker insertion in a pacemaker-dependent patient with bilateral subclavian occlusion and a failed epicardial system who is not suitable for a transfemoral approach.

Method and results

Procedure was undertaken under general anaesthesia with venous access obtained from right femoral vein and left axillary vein. 7F multipurpose catheter was used to enter proximal edge of the occluded segment of subclavian vein via femoral approach, which then supported stiff angioplasty wires and microcatheters to tunnel into the body of occlusion. When encountered with impenetrable resistance, 1.4 mm Excimer laser helped delivery of a Pilot 200 wire, which then progressed towards the distal edge of occlusion. Serial balloon dilatations allowed wire tracked into subintimal plane, advanced towards left clavicle using knuckle wire technique, which was then externalized with blunt dissection from infraclavicular pocket area. It was later changed to Amplatz superstiff wire exiting from both ends to form a rail, which ultimately allowed passage of pacing leads after serial balloon dilatation from clavicular end.

Conclusion

Our hybrid 'inside-out' technique permitted transvenous pacemaker insertion without complication and this is, to our knowledge, the first case using laser in this context.

Venous stenosis and occlusion in the presence of endocardial leads in patients referred for transvenous lead extraction

Objective The aim of this study was to evaluate the incidence of venous stenosis and occlusion (VSO) in patients referred for transvenous lead extraction (TLE) with regard to the indications for this treatment and to analyse the influence of VSO on efficacy, complications and technical challenges of TLE procedures. Methods The material consists of 133 consecutive TLE procedure records. The contrast venography examination of the ipsilateral access vein was performed prior to the operation. The whole study population was divided into two subgroups, based on the presence (subgroup I) or absence (subgroup II) of VSO. Results Phlebography was performed in 133 patients with age ranging from 25.7 to 86.1 years, 44 female (33.1%). The VSO was confirmed in 48 (36.1%) patients - subgroup I. Most of the patients were referred to TLE due to non-infectious reasons (100 pts-75.2%). The absence of VSO was observed substantially more frequently in patients with diabetes (P = 0.02). Procedural success rate reached 93.3% in subgroup I and 98.8% in subgroup II (P = 0.1). There was no significant difference in the use of advanced tools and alternative access sites. Conclusion The presence of VSO can be expected in one third of patients referred for lead extraction. There is no association between indication for TLE (infected or noninfected lead extraction) and the incidence of VSO. Diabetes proved to have a protective effect on venous patency in the previously mentioned group. VSO does not influence the effectiveness, safety, and the use of additional tools during TLE procedures.

Why the Authors Use Cardiac Resynchronization Therapy with Defibrillators

Cardiac resynchronization therapy (CRT) improves left ventricular function, especially in patients with left bundle branch block or those receiving chronic right ventricular pacing. CRT is typically accomplished by placing a right ventricular endocardial pacing lead and a left ventricular pacing lead via the coronary sinus to a coronary vein overlying the lateral or posterolateral left ventricle. CRT can be combined with an implantable defibrillator or with a pacemaker. Limited data are available to compare these two versions of CRT head to head. This review summarizes the relevant trials and meta-analyses regarding these two forms of CRT.

Venous Stenosis After Transvenous Lead Placement: A Study of Outcomes and Risk Factors in 212 Consecutive Patients

BACKGROUND

Venous stenosis is a common complication of transvenous lead implantation, but the risk factors for venous stenosis have not been well defined to date. This study was designed to evaluate the incidence of and risk factors for venous stenosis in a large consecutive cohort.

METHODS AND RESULTS

A total of 212 consecutive patients (136 male, 76 female; mean age 69 years) with existing pacing or implantable cardioverter-defibrillator systems presented for generator replacement, lead revision, or device upgrade with a mean time since implantation of 6.2 years. Venograms were performed and percentage of stenosis was determined. Variables studied included age, sex, number of leads, lead diameter, implant duration, insulation material, side of implant, and anticoagulant use. Overall, 56 of 212 patients had total occlusion of the subclavian or innominate vein (26%). There was a significant association between the number of leads implanted and percentage of venous stenosis (P=0.012). Lead diameter, as an independent variable, was not a risk factor; however, greater sum of the lead diameters implanted was a predictor of subsequent venous stenosis (P=0.009). Multiple lead implant procedures may be associated with venous stenosis (P=0.057). No other variables approached statistical significance.

CONCLUSIONS

A significant association exists between venous stenosis and the number of implanted leads and also the sum of the lead diameters. When combined with multiple implant procedures, the incidence of venous stenosis is increased.

Right giant atrial thrombosis and pulmonary embolism complicating pacemaker leads

We describe a case of a patient with bilateral pulmonary embolism because of a giant intracardiac thrombus anchored on a right atrial pacemaker lead treated with unfractionated heparin and the consecutively complete thrombus resolution after 5-6 days.

[Superior vena cava syndrome induced by pacemaker probes, 12 years after introduction]

Superior vena cava syndrome is a rare disease, most often found to result from a malignant process, which causes extrinsic compression of the superior vena cava. In recent years, there has been an increase of superior vena cava syndrome related to medical devices (implantable site, pacemaker [PM], central venous line for parenteral nutrition...). We report the case of a 37-year-old patient who developed a superior vena cava syndrome 12 years after implantation of a PM. The diagnosis was established on venography after two negative venous-CT focused on the superior vena cava. The superior vena cava syndrome improved immediately after angioplasty and stenting covering the PM probes at the superior vena cava/brachiocephalic venous trunk junction.

Endovascular recanalization of central venous access to allow for pacemaker implantation or upgrade

BACKGROUND

Several patients undergoing permanent pacemaker (PPM) implantation/upgrade present with difficult access due to sub- or total central vein occlusion. Our institution has used the endovascular approach to recanalize central veins to allow for subsequent PPM implantation. Here we aim to describe the feasibility and safety of using this approach to allow for PPM implantation/upgrade.

METHODS

From October 2006 to November 2010, 50 consecutive patients who underwent central vein recanalization prior to PPM implantation were included in this analysis.

RESULTS

The population's mean age was 70 years, with a high rate of comorbidities including chronic renal failure (52.0%), congestive heart failure (64.0%), diabetes (33.3%) and peripheral vascular disease (36.0%). The endovascular recanalization procedure was performed via femoral access in all patients; however adjuvant brachial access was required in 13 cases and subclavian vein in one. Subclavian vein (74.5%) followed by innominate vein (21.6%) were the most common locations/target for recanalization. Successful vein recanalization followed by successful PPM implantation/upgrade was achieved in 48 patients (96.0%) without peri-procedural complications. Two patients died during the hospitalization, one due to severe respiratory failure and a second due to complicated end-stage renal disease, although neither was related to the endovascular procedure. No other event, including myocardial infarction, cerebral-vascular accident, bleeding/transfusion, or renal failure was identified.

CONCLUSIONS

This study proved the feasibility and safety of the endovascular approach to recanalize central veins in patients with poor vascular access to allow for further PPM implantation/upgrade.

Be aware of wires in the veins: a case of superior vena cava syndrome in a patient with permanent pacemaker

Superior vena cava (SVC) syndrome is an unusual complication of pacemaker and implantable cardioverter–defibrillator implantation. It is believed to be due to SVC thrombosis with or without stenosis induced by endothelial disruption from repeated mechanical trauma by the leads. A 58-year-old man presented with gradual swelling of his face, neck, and upper extremities of 10 days duration. A pacemaker had been implanted for symptomatic bradycardia over 5 years ago. Venous Doppler and venogram revealed thrombosis and stenosis of the SVC. He was treated with multimodal therapy and was discharged with complete resolution of his symptoms.

Mobile Thrombus on Device Leads in Patients Undergoing Ablation

Background—

Mobile thrombi, not routinely recognized on transthoracic echocardiography, are frequently identified on cardiovascular implantable electronic device leads with intracardiac echocardiography (ICE) during ablation procedures. Their incidence, characteristics, and consequences have not yet been defined.

Methods and Results—

We used ICE to examine leads for thrombi and to measure the pulmonary artery systolic pressure in patients with a cardiovascular implantable electronic device presenting for ablation. Patient clinical characteristics, device type, and lead characteristics were correlated with presence of thrombi. Most patients had congestive heart failure (84%), with an average left ventricular ejection fraction of 40%. Thrombi were seen with ICE in 26 of 86 patients (30%) but were seen on transthoracic echocardiography in only 1 of the 26 patients. Thrombi on ICE were mobile, averaged 18±5.9 mm long by 4.4±2.3 mm wide, and were more commonly identified in the right atrium (n=25) than in the right ventricle (n=5). Thrombi were associated with higher pulmonary artery systolic pressure: 39±9 mm Hg with thrombi versus 33±7 mm Hg without thrombi (odds ratio, 1.11; 95% confidence interval, 1.03 to 1.20; P =0.01). No other characteristic assessed was associated with a significant difference in the presence of lead thrombi.

Conclusions—

Mobile thrombi on cardiovascular implantable electronic device leads are present in 30% of patients undergoing ablation and are readily identified with ICE despite being underrecognized with transthoracic echocardiography. Further study is warranted to determine whether lead thrombi are a clinically relevant source of pulmonary emboli in some patients with cardiovascular implantable electronic devices.

No increased bleeding events with continuation of oral anticoagulation therapy for patients undergoing cardiac device procedure

BACKGROUND

Switching warfarin for heparin has been a practice for managing periprocedural anticoagulation in high-risk patients undergoing device-related procedures. We sought to investigate whether continuation of warfarin sodium therapy without heparin bridging is safe and, when it is continued, the optimal international normalized ratio (INR) without increased bleeding risk at time of device-related procedure.

METHODS AND RESULTS

We retrospectively studied 766 consecutive patients taking warfarin long term who underwent device-related procedures. Patients were grouped by treatment: discontinued warfarin (-warfarin, n = 243), no interruption of warfarin (+warfarin, n = 324), and discontinued warfarin with heparin bridging (+heparin, n = 199). The study primary endpoint was systemic bleeding or formation of moderate or severe pocket hematoma within 30 days of the procedure. Thirty-one (4%) patients had bleeding events, including pocket hematoma in 29 patients. The bleeding events occurred more often for +heparin (7.0%) than -warfarin (2.1%) or +warfarin (3.7%, P = 0.029). For +warfarin group, INR of 2.0-2.5 at time of procedure did not increase bleeding risk compared with INR less than 1.5 (3.7% vs 3.4%; P = 0.72), but INR greater than 2.5 increased the bleeding risk (10.0% vs 3.4%; P = 0.029). Concomitant aspirin use with warfarin significantly increased bleeding risk than warfarin alone (5.6% vs 1.4%, P = 0.02). Median length of hospitalization was significantly shorter for +warfarin than +heparin (1 vs 6 days; P < 0.001).

CONCLUSION

Continuation of oral anticoagulation therapy with an INR level of <2.5 does not impose increased risk of bleeding for device-related procedures, although precaution is necessary to avoid supratherapeutic anticoagulation levels.

Cranial Vena Caval Thrombosis Associated With Endocardial Pacing Leads in Three Dogs

Three dogs were examined several years following implantation of transvenous, single-lead, endocardial, right-ventricular permanent pacing systems for signs consistent with cranial vena caval syndrome. Angiograms performed in all dogs revealed filling defects within the cranial vena cava and, in some instances, intracardiac filling defects. Medical therapy was instituted in two dogs, with one surviving several weeks. One dog underwent surgery to address intra-cardiac thrombosis but did not survive the immediate postoperative period. Postmortem examinations were performed in two dogs and confirmed cranial vena caval and intracardiac thrombosis. Cranial vena caval thrombosis associated with transvenous pacing leads appears to carry significant morbidity and mortality.

Utility and safety of axillo-subclavian venous imaging with carbon dioxide (CO) prior to chronic lead system revisions

BACKGROUND

Prior to attempting placement of one or more electrodes to revise existing rhythm control devices, patency of the central veins should be documented, in view of a high incidence of significant chronic occlusions. Since iodinated contrast venography may be contraindicated in select situations, imaging of the axillo-subclavian venous system with gaseous carbon dioxide (CO(2)) was evaluated prospectively in 23 consecutive individuals who were considered for revision of previously implanted pacemaker or automatic cardioverter defibrillator lead systems.

METHODS

Approximately 20 mL of CO(2) were manually infused via CO(2) primed injection tubing into a vein at or above the level of the antecubital fossa ipsilateral to the side of prior lead placements. Digital subtraction imaging over the axillo-subclavian region, lower neck, and mediastinum was performed. Formal interpretation was obtained from one of three interventional radiologists and at least one electrophysiologist.

RESULTS

Significant venous occlusions were identified in five (22%) patients. Vascular access utilized for the subsequent 18 revisions performed included the imaged patent ipsilateral vein in 14 patients and the contralateral, right-sided subclavian venous system in three patients. One patient required epicardial left ventricular lead placement. There were no complications from venography.

CONCLUSIONS

Axillo-subclavian venography with gaseous CO(2) in patients undergoing pacemaker or implantable cardioverter defibrillator lead revisions is feasible and safe when use of iodinated dye is contraindicated. This technique should be employed in patients with azotemia, dye contrast allergies, or significant inflammation in the vicinity of the intravenous line insertion.

A case of pacing lead induced clinical superior vena cava syndrome: a case report

Introduction

Transvenous pacing is a relatively safe treatment with a low complication rate, but serious thromboembolic complications have been reported to occur in 0.6% to 3.5% of cases. Superior vena cava obstruction syndrome is generally an uncommon but serious complication occurring in <0.1% of patients. However, when it occurs it carries with it significant morbidity and mortality.

Case presentation

A 51-year-old lady with long history of DDD permanent pacemaker presented following a mechanical fall. She had no obvious injuries, and was hemodynamically stable. General examination revealed features suggestive of Superior vena caval obstruction which was later confirmed by imaging. She was treated with long term oral anticoagulation with good clinical improvement.

Conclusion

Superior vena cava obstruction in patients with transvenous pacing leads, although rare, is a well recognized complication. With growing elderly population and increasing number of procedures performed, more and more people with permanent pacemaker are likely to be encountered in clinical practice. One should carefully look for thromboembolic complications during follow-up in patients with transvenous pacemaker leads, as it has implications for future management and carries significant morbidity and mortality.

Progression of venous pathology after pacemaker and cardioverter-defibrillator implantation: A prospective serial venographic study

BACKGROUND AND AIMS

Prospective data on development of venous obstruction after electrode implantation are limited. We performed a prospective study on 150 patients undergoing first pacemaker implantation.

METHODS

Venographies at base-line and 6 months postimplantation in all patients, 50 patients included into a long-term follow-up of a mean of 2.4 years after implantation.

RESULTS

At 6 months 14% had obstructions, but only 1 patient (0.7%) developed acute symptomatic upper extremity venous thrombosis. Pulmonary embolism (PE) was encountered in 5 (3.3%). After 6 months only 2 patients experienced pain in ipsilateral arm, but none had edema of arm, neck or head, or clinical PE. The 5 patients with total venous occlusion (TVO) at 6 months had no localized symptoms. Late venographic abnormalities developed in 5 (10%) patients: 4 TVOs and 1 stenosis. Two of the new lesions developed among 25 patients with normal 6-month venograms. Overall, TVO was detected in 9 of 150 patients. No factors emerged as independent predictors of total occlusion in multiple regression analysis.

CONCLUSIONS

TVO is not uncommon after pacemaker implantation, and mostly occurs without any localizing symptoms. Most venous lesions seem to develop during the first months postimplantation, but late and unpredictable TVO may also occur.

[Strategies for the avoidance and treatment of complications during pacemaker implantation]

The implantation of a pacemaker is the therapy of choice for symptomatic bradyarrhythmias. The perioperative complication rate is low. This article gives an overview on possible complications, their avoidance and treatment.

Successful coronary sinus lead replacement despite total venous occlusion using femoral pull through, two operator counter-traction and subclavian venoplasty

The majority of patients presenting for lead extraction have indications for a replacement lead. Venous stenosis is common in recipients of pacing leads and can impede ipsilateral lead replacement. Recanalization through an existing tract after lead extraction allows successful lead placement but may require complex hybrid lead extraction and revascularization techniques. We present a case in which a combination of femoral lead extraction with complete guidewire pull-through, two operator external counter-traction and subclavian venoplasty was used to successfully replace a coronary sinus lead in a patient with total subclavian venous occlusion.

Predictors of venous obstruction following pacemaker or implantable cardioverter-defibrillator implantation: a contrast venographic study on 100 patients admitted for generator change, lead revision, or device upgrade

AIM

Venous obstruction following transvenous device implantation rarely cause immediate clinical problems. When lead revision or device upgrade is indicated, venous obstruction become a significant challenge. The aim of this study was to determine the predictors of venous obstruction after transvenous device implantation, and to asess likely effects of antiplatelet/anticoagulant drugs in preventing venous thrombosis.

METHODS AND RESULTS

Between March 2005 and July 2006, contrast venography was performed in 100 patients who were candidates for generator change, lead revision, or device upgrade. Vessel patency was graded as either completely obstructed, partially obstructed (>70%), or patent. The incidence of venous obstruction was 26%, with 9% of patients having total obstruction and 17% of patients exhibiting partial obstruction. No statistically significant differences between obstructed and non-obstructed patients were seen for age, sex, indication for device implantation, atrial fibrillation, cardiothoracic ratio, insulation material, operative technique, device type, and manufacturer (all Ps > 0.05). In a univariate analysis, multiple leads (P = 0.033), and presence of dilated cardiomyopathy (P = 0.036) were associated with higher risk of venous obstruction, whereas anticoagulant/antiplatelet therapy (P = 0.047) significantly reduced incidence of venous obstruction. Multivariate logistic regression analysis showed that only number of the leads (P = 0.039, OR: 2.22, and 95% CI: 1.03-4.76) and antiplatelet/anticoagulant therapy (P = 0.044, OR: 2.79, and 95% CI: 0.98-7.96) were predictors of venous obstruction.

CONCLUSION

Total or partial obstruction of the access veins occurs relatively frequently after pacemaker or ICD implantation. Multiple pacing or ICD leads are associated with an increased risk of venous obstruction, whereas antiplatelet/anticoagulant therapy appears to have a preventive effect on development of access vein thrombosis.