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

Venoplasty of a chronic venous occlusion with 'diathermy' for cardiac device lead placement

Venous revascularization is an approach used in patients with total venous occlusion requiring venous access for cardiac device lead placement. Several percutaneous approaches to venous revascularization have been proposed. For the first time, we describe the case of a 69-year-old male with total venous occlusion who was successfully revascularized using a 'diathermy' technique.

Health-related quality of life impact of a transcatheter pacing system

BACKGROUND

Transcatheter pacing systems (TPS) provide a novel, minimally invasive approach in which a miniaturized, leadless pacemaker (PM) is transfemorally implanted in the right ventricle. We evaluated the health-related quality of life (HRQoL) impact, patient satisfaction, and activity restrictions following TPS in a large prospective multicenter clinical trial.

METHODS AND RESULTS

Patients who underwent a Micra TPS implantation between December 2013 and May 2015 were included. HRQoL impact was evaluated using the Short-Form-36 (SF-36) questionnaire at baseline, 3, and 12 months. Patient satisfaction was assessed using a three-item questionnaire determining recovery, activity level, and esthetic appearance at 3 months. Implanting physicians compared the patient activity restrictions for TPS to traditional PM therapy. A total of 720 patients were implanted with a TPS (76 ± 11 years; 59% male). Of these patients, 702 (98%), 681 (95%), and 635 (88%) completed the SF-36 at baseline, 3 and 12 months, respectively. Improvements were observed at 3 and 12 months in all SF-36 domains and all attained statistical significance. Of 693 patients who completed the patient satisfaction questionnaire, 96%, 91%, 74% were (very) satisfied with their esthetic appearance, recovery, and level of activity, respectively. TPS discharge instructions were rated less restrictive in 49%, equally restrictive in 47%, and more restrictive in 4% of cases compared with traditional PM systems.

CONCLUSIONS

TPS resulted in postimplant HRQoL improvements at 3 and 12 months, and high levels of patient satisfaction at 3 months. Further, TPS was associated with less activity restrictions compared with traditional PM systems.

Candidacy for a Subcutaneous Implantable Cardioverter Defibrillator in Patients with Cardiac Resynchronization Therapy

In patients requiring an implantable cardioverter defibrillator (ICD), the combined use of a prior pacemaker and a subcutaneous ICD (S-ICD) could be an alternative treatment option to implantation of new leads or upgrading of pacemakers to an ICD if vascular access is limited. Here, we assessed the prevalence of S-ICD's eligibility according to surface electrogram screening in those receiving cardiac resynchronization therapy (CRT). S-ICD's eligibility was assessed in patients with a CRT pacemaker or a CRT defibrillator using the S-ICD template screening tool. Eligibility was defined as fulfillment of the template in both supine and upright positions in one or more leads during biventricular pacing. Among 44 patients (34 men, age: 67 ± 12), 36 (82%) were found to be eligible. The T/QRS amplitude ratio in lead II was significantly lower in those who were eligible (0.31 ± 0.16 versus 0.44 ± 0.18 in the ineligible group, P = 0.04). The lead position, underlying disease, and other electrocardiographic findings were not different between those who were eligible and those who were not. The majority of patients with biventricular pacing were eligible for S-ICD based on current screening tests and may benefit from this treatment. Further study is required.

Usefulness of preoperative venography in patients with cardiac implantable electronic devices submitted to lead replacement or device upgrade procedures

Background

Venous obstructions are common in patients with transvenous cardiac implantable electronic devices, but they rarely cause immediate clinical problems. The main consequence of these lesions is the difficulty in obtaining venous access for additional leads implantation.

Objectives

We aimed to assess the prevalence and predictor factors of venous lesions in patients referred to lead reoperations, and to define the role of preoperative venography in the planning of these procedures.

Methods

From April 2013 to July 2016, contrast venography was performed in 100 patients referred to device upgrade, revision and lead extraction. Venous lesions were classified as non-significant (< 50%), moderate stenosis (51-70%), severe stenosis (71-99%) or occlusion (100%). Collateral circulation was classified as absent, discrete, moderate or accentuated. The surgical strategy was defined according to the result of the preoperative venography. Univariate analysis was used to investigate predictor factors related to the occurrence of these lesions, with 5% of significance level.

Results

Moderate venous stenosis was observed in 23%, severe in 13% and occlusions in 11%. There were no significant differences in relation to the device side or the venous segment. The usefulness of the preoperative venography to define the operative tactic was proven, and in 99% of the cases, the established surgical strategy could be performed according to plan.

Conclusions

The prevalence of venous obstruction is high in CIED recipients referred to reoperations. Venography is highly indicated as a preoperative examination for allowing the adequate surgical planning of procedures involving previous transvenous leads.

Complications associated with cardiac resynchronization therapy upgrades versus de novo implantations

INTRODUCTION

A significant number of patients undergo upgrade to cardiac resynchronization therapy (CRT). These patients tend to differ from individuals undergoing de novo CRT implantations both in terms of their baseline demographics and the etiology underlying their heart failure. Areas covered: There are several factors that need to be considered when upgrading patients to CRT, such as, venous patency. Potentially, these conditions can cause issues which may result in procedures being more difficult than de novo implantations. This article discusses these issues and compares the rates of procedural-related complications for CRT upgrades and de novo implantations. It discusses the proportion of patients that are likely to respond to CRT with each intervention. Expert commentary: Understanding the relative risks of CRT upgrades versus de novo implantations is important to help operators select the correct initial device and counsel patients accordingly. Growing experience with image-guided implantations and endocardial pacing may prove to be particularly relevant to patients undergoing CRT upgrades.

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.

Comparison of single-coil lead versus dual-coil lead of implantable cardioverter defibrillator on lead-related venous complications in a canine model

PURPOSE

Dual- coil lead (DCL) of implantable cardioverter defibrillator (ICD) is preferred clinically in patients. However, it is related to higher risk of venous stenosis and thrombosis. The present study was done to compare the fibrosis and extraction of the leads between the single-coil lead (SCL) and DCL in animal models.

METHODS

This was a chronic animal study with a follow-up duration of 6 months. Twenty mongrel dogs were randomly divided into DCL group or SCL group. Venography was performed before the sacrifice to evaluate the venous stenosis in vivo. The maximum pulling-out tension of the ICD lead was measured by a tensometer. Hematoxylin-eosin stain and toluidine blue O stain were applied to show the pathological changes of the superior vena cava (SVC) to evaluate the fibrosis and the thickness of the SVC adjacent to the leads.

RESULTS

The DCL group showed higher incidence of venous stenosis (OR = 31.5; 95% CI, 2.35-422.3; p = 0.005). It revealed increased tension to extract the leads in the DCL group (5.96 ± 1.86 vs. 3.68 ± 1.46 N, p = 0.027). The difference of venous wall thickness of SVC was 4.3 ± 0.3 fold-changes between two groups (p = 0.007). Moreover, the degree of venous wall fibrosis in DCL group was more serious than that it in SCL group (3.61 ± 1.26 vs. 1.08 ± 1.35 mm², p = 0.015).

CONCLUSION

The DCL was proved to increase thrombosis, fibrosis, and stenosis in the SVC. Likewise, the DCL was mechanically harder to be extracted than the SCL. Our study showed that lead-related complications of the DCLs were higher than those of the SCLs regardless of the equal defibrillation thresholds between them. Results of the present study would help to choose the proper lead which could be removed.

Cardiac implantable electronic device and vascular access: Strategies to overcome problems

For arrhythmia treatment or sudden cardiac death prevention in hemodialysis patients, there is a frequent need for placement of a cardiac implantable electronic device (pacemaker, implantable cardioverter defibrillator, or cardiac resynchronization device). Leads from a cardiac implantable electronic device can cause central vein stenosis and carry the risk of tricuspid regurgitation or contribute to infective endocarditis. In patients with end-stage kidney disease requiring vascular access and cardiac implantable electronic device, the best strategy is to create an arteriovenous fistula on the contralateral upper limb for a cardiac implantable electronic device and avoidance of central vein catheter. Fortunately, cardiac electrotherapy is moving toward miniaturization and less transvenous wires. Whenever feasible, one should avoid transvenous leads and choose alternative options such as subcutaneous implantable cardioverter defibrillator, epicardial leads, and leadless pacemaker. Based on recent reports on the leadless pacemaker/implantable cardioverter defibrillator effectiveness, in patients with rapid progression of chronic kidney disease (high risk of renal failure) or glomerular filtration rate <20 mL/min/1.73 m², this option should be considered by the implanting cardiologist for future access protection.

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.

Coronary Venous Lead Extraction

The increasing number of cardiac resynchronization therapy devices implanted, coupled with the increasing incidence of cardiac implantable electronic device infection, has led to a greater need for extraction of coronary venous pacing leads. The objectives of this study were to review the indications, techniques and published results of coronary venous lead extraction. In this study, we searched PubMed using the search terms "lead extraction," "coronary sinus," "coronary venous," "pacing," and "cardiac resynchronization therapy" for relevant papers. The reference lists of relevant articles were also searched, and personal experience was drawn upon. Published success rates and complications were found to be similar to those reported for non-coronary venous leads in experienced centers. However, reimplantation success differs and can be limited by vessel occlusion postextraction. The available active fixation coronary sinus lead (Attain Starfix™; Medtronic, MN, USA) is a particularly complex lead to extract, whereas limited data on the newer active fixation leads (Attain Stability™, Medtronic, MN, USA) suggest that they are less challenging to remove. The study concluded that coronary venous lead extraction presents unique challenges, especially reimplantation, that require special consideration and planning to overcome.

Permanent Leadless Cardiac Pacemaker Therapy

A new technology, leadless pacemaker therapy, was recently introduced clinically to address lead- and pocket-related complications in conventional transvenous pacemaker therapy. These leadless devices are self-contained right ventricular single-chamber pacemakers implanted by using a femoral percutaneous approach. In this review of available clinical data on leadless pacemakers, early results with leadless devices are compared with historical results with conventional single-chamber pacing. Both presently manufactured leadless pacemakers show similar complications, which are mostly related to the implant procedure: cardiac perforation, device dislocation, and femoral vascular access site complications. In comparison with conventional transvenous single-chamber pacemakers, slightly higher short-term complication rates have been observed: 4.8% for leadless pacemakers versus 4.1% for conventional pacemakers. The complication rate of the leadless pacemakers is influenced by the implanter learning curve for this new procedure. No long-term outcome data are yet available for the leadless pacemakers. Larger leadless pacing trials, with long-term follow-up and direct randomized comparison with conventional pacing systems, will be required to define the proper clinical role of these leadless systems. Although current leadless pacemakers are limited to right ventricular pacing, future advanced, communicating, multicomponent systems are expected to expand the potential benefits of leadless therapy to a larger patient population.

Hemodialysis Tunneled Catheter Noninfectious Complications

Noninfectious hemodialysis catheter complications include catheter dysfunction, catheter-related thrombus, and central vein stenosis. The definitions, causes, and treatment strategies for catheter dysfunction are reviewed below. Catheter-related thrombus is a less common but serious complication of catheters, requiring catheter removal and systemic anticoagulation. In addition, the risk factors, clinical manifestation, and treatment options for central vein stenosis are outlined.

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.

Canadian Cardiovascular Society/Canadian Heart Rhythm Society 2016 Implantable Cardioverter-Defibrillator Guidelines

Sudden cardiac death is a major public health issue in Canada. However, despite the overwhelming evidence to support the use of implantable cardioverter defibrillators (ICDs) in the prevention of cardiac death there remains significant variability in implantation rates across Canada. Since the most recent Canadian Cardiovascular Society position statement on ICD use in Canada in 2005, there has been a plethora of new scientific information to assist physicians in their discussions with patients considered for ICD implantation to prevent sudden cardiac death due to ventricular arrhythmias. We have reviewed, critically appraised, and synthesized the pertinent evidence to develop recommendations regarding: (1) ICD implantation in the primary and secondary prevention of sudden cardiac death in patients with and without ischemic heart disease; (2) when it is reasonable to withhold ICD implantation on the basis of comorbidities; (3) ICD implantation in patients listed for heart transplantation; (4) implantation of a single- vs dual-chamber ICD; (5) implantation of single- vs dual-coil ICD leads; (6) the role of subcutaneous ICDs; and (7) ICD implantation infection prevention strategies. We expect that this document, in combination with the companion article that addresses the implementation of these guidelines, will assist all medical professionals with the care of patients who have had or at risk of sudden cardiac death.

Hemodialysis Tunneled Catheter Noninfectious Complications

Noninfectious hemodialysis catheter complications include catheter dysfunction, catheter-related thrombus, and central vein stenosis. The definitions, causes, and treatment strategies for catheter dysfunction are reviewed below. Catheter-related thrombus is a less common but serious complication of catheters, requiring catheter removal and systemic anticoagulation. In addition, the risk factors, clinical manifestation, and treatment options for central vein stenosis are outlined.

The utility of a CHA2DS2-VASc score in predicting the presence of significant stenosis and occlusion of veins with indwelling endocardial leads

BACKGROUND

Currently, there are no studies in which a CHA2DS2-VASc score has been used to predict the risk of venous stenosis and occlusion (VSO) in patients after the implantation of a cardiac implantable electronic device (CIED).

METHODS

The material consists of the records of 223 consecutive patients qualified for transvenous lead extraction, generator change and system revisions or upgrades in whom we assessed the utility of a CHA2DS2-VASc score in the prediction of VSO. The CHA2DS2-VASc score was calculated retrospectively based on the clinical data. The whole study population was divided into two groups, based on the presence (group I) or absence (group II) of VSO. Using the receiver operating characteristic (ROC) curve, we identified the optimal cut-off point for the CHA2DS2-VASc score that allowed the prediction of the absence of VSO.

RESULTS

The venography was performed in 223 consecutive patients aged on average 68.2years (25.7-95.3), 77 females (34.5%). The presence of VSO was detected in 79 (35.4%) patients aged 68.3±14.1years, 30 female (40%) patients-group I. The level of the cut-off point for the CHA2DS2-VASc score that allowed the prediction of the absence of VSO was 3.0.

CONCLUSION

In the whole population the incidence of VSO amounted to 35.4%. The result of the CHA2DS2-VASc score was a destimulant of VSO occurrence and was characterized by moderate sensitivity (73.4%) and specificity (42.4%) in predicting the absence of VSO. The most significant factor, which prevented VSO development was diabetes.

Prevalence and predictor factors of severe venous obstruction after cardiovascular electronic device implantation

AIMS

Despite not being uncommon, limited evidence exists about predisposing factors for venous obstruction in patients with implantable electronic devices. We aimed to assess the prevalence of severe venous obstruction in patients with intravenous devices and identify predictor factors.

METHODS AND RESULTS

A total of 184 patients underwent venography to detect venous obstruction associated with the inserted lead. Vessel obstruction was graded as venous occlusion (complete flow interruption), severe obstruction (narrowing >90%), or mild-moderate obstruction (narrowing 50-90%). Severe venous obstruction/occlusion prevalence was 11.4% (n = 21) and was always asymptomatic. Collateral circulation was found in 80.9% of patients with severe obstruction/occlusion. Twelve patients (6.5%) had 3 leads. The rates of patients with secondary prevention of sudden cardiac death as indication for implantable devices and of those of patients with 3 leads were significantly greater in the group with severe obstruction/occlusion than in the non-severe obstruction/occlusion group (respectively, P = 0.004 and P = 0.03). Logistic analysis adjusted for venous thromboembolic risk factors confirmed that secondary prevention of sudden cardiac death as indication for implantable devices [odds ratio (OR), 7.1; 95% confidence interval (CI): 1.4-35.3; P = 0.017] and the presence of 3 leads (OR, 8.5; 95% CI: 1.75-41.35; P = 0.008) were predictors of severe obstruction/occlusion.

CONCLUSION

In patients with implantable devices, severe venous obstruction prevalence is not negligible and the lack of symptoms does not exclude it. The presence of three leads and sudden cardiac death as indication for implantable devices seem to be associated with the presence of severe venous obstruction/occlusion.

Coronary Sinus Lead Extraction

Expanded indications for cardiac resynchronization therapy and the increasing incidence of cardiac implantable electronic device infection have led to an increased need for coronary sinus (CS) lead extraction. The CS presents unique anatomical obstacles to successful lead extraction. Training and facility requirements for CS lead extraction should mirror those for other leads. Here we review the indications, technique, and results of CS lead extraction. Published success rates and complications are similar to those reported for other leads, although multiple techniques may be required. Re-implantation options may be limited, which should be incorporated into pre-procedural decision making.

Percutaneous Implantation of an Entirely Intracardiac Leadless Pacemaker

BACKGROUND

Cardiac pacemakers are limited by device-related complications, notably infection and problems related to pacemaker leads. We studied a miniaturized, fully self-contained leadless pacemaker that is nonsurgically implanted in the right ventricle with the use of a catheter.

METHODS

In this multicenter study, we implanted an active-fixation leadless cardiac pacemaker in patients who required permanent single-chamber ventricular pacing. The primary efficacy end point was both an acceptable pacing threshold (≤2.0 V at 0.4 msec) and an acceptable sensing amplitude (R wave ≥5.0 mV, or a value equal to or greater than the value at implantation) through 6 months. The primary safety end point was freedom from device-related serious adverse events through 6 months. In this ongoing study, the prespecified analysis of the primary end points was performed on data from the first 300 patients who completed 6 months of follow-up (primary cohort). The rates of the efficacy end point and safety end point were compared with performance goals (based on historical data) of 85% and 86%, respectively. Additional outcomes were assessed in all 526 patients who were enrolled as of June 2015 (the total cohort).

RESULTS

The leadless pacemaker was successfully implanted in 504 of the 526 patients in the total cohort (95.8%). The intention-to-treat primary efficacy end point was met in 270 of the 300 patients in the primary cohort (90.0%; 95% confidence interval [CI], 86.0 to 93.2, P=0.007), and the primary safety end point was met in 280 of the 300 patients (93.3%; 95% CI, 89.9 to 95.9; P<0.001). At 6 months, device-related serious adverse events were observed in 6.7% of the patients; events included device dislodgement with percutaneous retrieval (in 1.7%), cardiac perforation (in 1.3%), and pacing-threshold elevation requiring percutaneous retrieval and device replacement (in 1.3%).

CONCLUSIONS

The leadless cardiac pacemaker met prespecified pacing and sensing requirements in the large majority of patients. Device-related serious adverse events occurred in approximately 1 in 15 patients. (Funded by St. Jude Medical; LEADLESS II ClinicalTrials.gov number, NCT02030418.).

Design and In Vivo Test of a Batteryless and Fully Wireless Implantable Asynchronous Pacing System

Goal: The aim of this study is to develop a novel fully wireless and batteryless technology for cardiac pacing.

METHODS

This technology uses radio frequency (RF) energy to power the implanted electrode in the heart. An implantable electrode antenna was designed for 1.2 GHz; then, it was tested in vitro and, subsequently, integrated with the rectifier and pacing circuit to make a complete electrode. The prototype implanted electrode was tested in vivo in an ovine subject, implanting it on the epicardial surface of the left ventricle. The RF energy, however, was transmitted to the implanted electrode using a horn antenna positioned 25 cm above the thorax of the sheep.

RESULTS

It was demonstrated that a small implanted electrode can capture and harvest enough safe recommended RF energy to achieve pacing. Electrocardiogram signals were recorded during the experiments, which demonstrated asynchronous pacing achieved at three different rates.

CONCLUSION

These results show that the proposed method has a great potential to be used for stimulating the heart and provides pacing, without requiring any leads or batteries. It hence has the advantage of potentially lasting indefinitely and may never require replacement during the life of the patient.

SIGNIFICANCE

The proposed method brings forward transformational possibilities in wireless cardiac pacing, and also in powering up the implantable devices.

Extraction of sterile leads is the preferred approach rather than implanting a new lead: the con perspective

Lead malfunction is a common problem in implantable cardiac device patients and is expected to increase with the aging of leads. There is a weak indication for extraction of superfluous leads with the potential for cardiac implantable electronic device interference and abandoned or redundant leads; much remains to be learned from clinical practice. Lead extraction, although safe in experienced hands, remains a high-risk procedure, especially in lower-volume centers and/or when performed by lower-volume operators. Therefore, a strategy of abandoning nonfunctioning leads is reasonable, and lead extractions should be reserved for cases with system infection or high lead burden.

To extract or retain a sterile, nonfunctional lead: the case for extraction

Decision-making regarding extracting or abandoning sterile but nonfunctioning ICD leads has to be individualized. Providing recommendations to patients and their families requires a careful weighing of pros and cons and understanding of the availability of local expertise. Decision models to help with these clinical scenarios have started to become available but remain in their infancy.

Contralateral transvenous left ventricular lead placement of implantable devices with pre-sternal tunnelling in chronically obstructed subclavian veins

Cardiac resynchronisation therapy (CRT) is a recognised therapy for the management of severe left ventricular dysfunction, advanced congestive cardiac failure (NYHA III or IV), ventricular dyssynchrony (either broad LBBB or mechanical dyssynchrony on echocardiography) and failure of optimal medical therapy to achieve improvement in clinical status. Upgrading right ventricular pacemakers or defibrillators to biventricular devices is common and we describe here, 2 such cases of biventricular upgrade with blocked venous access on the ipsilateral side and successful placement of left ventricular leads following pre-sternal tunnelling from the contralateral side.

Chronic performance of a leadless cardiac pacemaker: 1-year follow-up of the LEADLESS trial

BACKGROUND

A leadless cardiac pacemaker (LCP) system was recently introduced to overcome lead-related complications of conventional pacing systems. To date, long-term results of an LCP system are unknown.

OBJECTIVES

The aim of this study was to assess the complication incidence, electrical performance, and rate response characteristics within the first year of follow-up of patients implanted with an LCP.

METHODS

We retrospectively assessed intermediate-term follow-up data for 31 of 33 patients from the LEADLESS trial cohort who had an indication for single-chamber pacing and received an LCP between December 2012 and April 2013.

RESULTS

The mean age of the cohort was 76 ± 8 years, and 65% were male. Between 3 and 12 months of follow-up, there were no pacemaker-related adverse events reported. The pacing performance results at 6- and 12-month follow-up were, respectively, as follows: mean pacing threshold (at a 0.4-ms pulse width), 0.40 ± 0.26 V and 0.43 ± 0.30 V; R-wave amplitude 10.6 ± 2.6 mV and 10.3 ± 2.2 mV; and impedance 625 ± 205 Ω and 627 ± 209 Ω. At the 12-month follow-up in 61% of the patients (n = 19 of 31), the rate response sensor was activated, and an adequate rate response was observed in all patients.

CONCLUSIONS

The LCP demonstrates very stable performance and reassuring safety results during intermediate-term follow-up. These results support the use of the LCP as a promising alternative to conventional pacemaker systems. Continued evaluation is warranted to further characterize this system. (Evaluation of a New Cardiac Pacemaker; NCT01700244).

Prevalence of venous occlusion in patients referred for lead extraction: implications for tool selection

AIMS

Data concerning the incidence of venous obstruction in patients referred for lead extraction is limited. Thus, we aimed to assess the incidence of venous obstruction in patients referred for lead extraction and the implications for tool selection.

METHODS AND RESULTS

Contrast venography of the access vein was obtained in 202 patients (147 men; mean age, 62.4 ± 14.5 years) scheduled for lead extraction. The indication for lead extraction included infection (n = 145, 72%) and other causes (n = 57, 28%). Two patients with device infection had superior vena caval occlusion. Access vein occlusion occurred in 6 (11%) patients without infection vs. 46 (32%) patients with infection [P = 0.002; odds ratio (OR) 3.94; 95% confidence interval (CI) 1.58-9.87]. No significant differences between occluded and non-occluded patients were seen for age, sex, device type, number of leads, time from implant of the initial lead, or anticoagulation therapy (all P>0.05). Procedural duration and fluoroscopy exposure time were significantly lower in the open group than in the occluded group (P < 0.05). Patients with venous occlusion required more advanced tools for lead extraction, such as dilator sheaths, evolution sheaths, and needle's eye snares (P = 0.019).

CONCLUSION

Both systemic and local infections are associated with increased risk of access vein occlusion. We found no support for the hypothesis that venous occlusion increases with the number of leads present. Lead extraction was more difficult in patients with venous occlusion, requiring advanced tools and more time.

Permanent pacing in patients without upper limb venous access: a review of current techniques

Permanent transvenous cardiac pacing is usually accomplished through the upper limb veins. When these are occluded, several other vascular access options exist which include the internal jugular, external jugular, femoral and iliac veins as well as more proximal access of the subclavian veins. Anterograde and retrograde techniques to restore subclavian venous patency has been described. A review of these approaches is undertaken, with a discussion of their pros and cons. Familiarity with these techniques will enable the implanter to perform transvenous pacing when faced with limited vascular access.

Cardiovascular implantable electronic devices in hemodialysis patients: prevalence and implications for arteriovenous hemodialysis access interventions

Cardiovascular implantable electronic devices (CIEDs) are frequently utilized in hemodialysis patients. CIED leads are typically implanted via the subclavian vein resulting in stenosis and venous hypertension. We studied 1235 chronic hemodialysis patients under the care of our nephrology practice. For each, we determined the presence of a CIED, indication for implantable cardioverter-defibrillator (ICD), and type of hemodialysis access. Records were reviewed to identify all interventions performed on the access circuit and the central veins specifically. A CIED was present in 129 patients (10.5%), including ICDs in 75 (6.1%) and pacemakers in 54 (4.4%). The access circuit intervention rate was 1.48/access year (AY) and was similar when a CIED was ipsilateral (1.53/AY) or contralateral (1.44/AY) to arteriovenous access (p = 0.477). The rate of central venous interventions was greater in the ipsilateral (0.59/AY) versus contralateral group (0.28/AY), (p < 0.001). Fifty-four of 59 patients with ipsilateral access and CIED required <2 interventions per AY, but six failed angioplasty and required access ligation. None had superior vena cava stenosis requiring intervention. We conclude that there is a high prevalence of CIEDs in our HD patients. Ipsilateral CIED and arteriovenous access results in higher central venous intervention rates compared with contralateral cases; overall access circuit intervention rates are similar.

Implanted endocardial lead characteristics and risk of stroke or transient ischemic attack

INTRODUCTION

Patent foramen ovale (PFO) has been recently implicated as a strong predictor of stroke or transient ischemic attack (TIA) in patients with implanted pacemaker or defibrillation leads. Leads in the right heart can form thrombi that embolize to the pulmonary circulation and raise pulmonary pressure. This increases right-to-left shunting through PFO or intrapulmonary shunts and can result in paradoxical embolism. We sought to determine whether certain lead characteristics confer a higher thrombogenic risk resulting in stroke/TIAs in patients either with or without a PFO.

METHODS

We retrospectively analyzed 5,646 patients (mean age 67.3 ± 16.3 years, 64 % male) who had endocardial device leads implanted in 2000-2010. We performed univariate and multivariate-adjusted proportional hazards models to determine association of lead characteristics with stroke/TIA during follow-up.

RESULTS

On univariate analysis, passively fixated tined leads were associated with more stroke/TIAs (HR 1.77, 95 % CI 1.27, 2.47; p<0.001), whereas presence of defibrillation coil was associated with fewer stroke/TIAs (HR 0.59, 95 % CI 0.42-0.84; p=0.003). Number of leads per patient, presence of atrial lead, maximum lead size, tip shape, and type of insulating material were not associated with stoke/TIA. On multivariate analyses adjusting for age, sex, diagnosis of PFO, and prior history of stroke/TIA, the presence of tined leads was associated with stroke/TIA (HR 1.41, 95 % CI 1.00-1.97; p=0.049). Defibrillation coils were no longer associated with lower stroke/TIA on multivariate analysis.

CONCLUSIONS

Most physical characteristics of contemporary leads do not impact rate of stroke/TIA among patients receiving implantable devices. The presence of a PFO is a major risk factor for stroke/TIA in patients with endovascular leads.

Permanent leadless cardiac pacing: results of the LEADLESS trial

BACKGROUND

Conventional cardiac pacemakers are associated with several potential short- and long-term complications related to either the transvenous lead or subcutaneous pulse generator. We tested the safety and clinical performance of a novel, completely self-contained leadless cardiac pacemaker.

METHODS AND RESULTS

The primary safety end point was freedom from complications at 90 days. Secondary performance end points included implant success rate, implant time, and measures of device performance (pacing/sensing thresholds and rate-responsive performance). The mean age of the patient cohort (n=33) was 77±8 years, and 67% of the patients were male (n=22/33). The most common indication for cardiac pacing was permanent atrial fibrillation with atrioventricular block (n=22, 67%). The implant success rate was 97% (n=32). Five patients (15%) required the use of >1 leadless cardiac pacemaker during the procedure. One patient developed right ventricular perforation and cardiac tamponade during the implant procedure, and eventually died as the result of a stroke. The overall complication-free rate was 94% (31/33). After 3 months of follow-up, the measures of pacing performance (sensing, impedance, and pacing threshold) either improved or were stable within the accepted range.

CONCLUSIONS

In a prospective nonrandomized study, a completely self-contained, single-chamber leadless cardiac pacemaker has shown to be safe and feasible. The absence of a transvenous lead and subcutaneous pulse generator could represent a paradigm shift in cardiac pacing.

CLINICAL TRIAL REGISTRATION URL

http://clinicaltrials.gov. Unique identifier: NCT01700244.

Laser lead extraction to facilitate cardiac implantable electronic device upgrade and revision in the presence of central venous obstruction

Aims

The number of procedures involving upgrade or revision of cardiac implantable electronic devices (CIEDs) is increasing and the risks of adding additional leads are significant. Central venous occlusion in patients with pre-existing devices is often asymptomatic and optimal management of such patients in need of device revision/upgrade is not clear. We sought to assess our use of laser lead extraction in overcoming venous obstruction.

Methods and results

Patients in need of device upgrade/revision underwent pre-procedure venography to assess venous patency. In patients with venous occlusion or stenosis severe enough to preclude passage of a hydrophilic guide wire, laser lead extraction with retention of the outer sheath in the vasculature was performed with the aim of maintaining a patent channel through which new leads could be implanted. Data were recorded on a dedicated database and patient outcomes were assessed. Between July 2004 and April 2012, laser lead extractions were performed in 71 patients scheduled for device upgrade/revision who had occluded or functionally obstructed venous anatomy. New leads were successfully implanted across the obstruction in 67 (94%) cases. There were two major complications (infection) and four minor complications with no peri-procedural mortality. Device follow-up was satisfactory in 65 (92%) cases with mean follow-up up to 26 ± 19 months.

Conclusion

Laser lead extraction is a safe and effective option when managing patients with central venous obstruction in need of CIED revision or upgrade.

[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.

Pacing device therapy in infants and children: a review

The number of pediatric pacemakers implanted is still relatively small. Children requiring pacing therapy have characteristics that are distinct from those of adults, including physical size, somatic growth, and cardiac anomalies. Considering these features, long-term follow-up of pediatric pacemaker implantation is necessary. Selection of appropriate generators, pacing modes, pacing sites, and leads is important. Generally, epicardial leads are commonly used in small infants. On the other hand, the use of endocardial leads in children is increasing worldwide because of their benefits over epicardial leads, such as minimal invasiveness, lower pacing threshold, and longer generator longevity. Endocardial leads are not suitable for patients with intracardiac shunts because of the high risk of systemic thrombosis. Venous occlusion is another significant problem with endocardial leads. With the increase in the number of pacing device implantations, the incidence of infection from such devices is also increasing. Complete device removal is sometimes recommended to treat device infection, but experience in the removal of endocardial leads in children is still scarce. This article gives an overview of pacing therapy in the pediatric population, including discussions on new pacing systems, such as remote monitoring systems, magnetic imaging compliant pacemaker systems, and leadless pacing devices.

Patent foramen ovale. Correct route for implantation of a biventricular permanent pacemaker?

INTRODUCTION

Intentional or unintentional placement of a pacemaker lead into the left ventricle is an uncommon clinical entity that is associated with a high risk for systemic embolization and enormous difficulties in case of explantation. Unintentional implantation through a patent foramen ovale via the mitral valve is the usual pathway for this malposition.

METHODS

We report a case where a pacemaker lead was placed intentionally into the left ventricle via a patent foramen ovale for biventricular pacing for resynchronization therapy. Later, the patient developed life-threatening pacemaker lead-associated endocarditis with sepsis. Emergency open heart surgery for lead removal was necessary in the form of a reoperation after bypass graft surgery a number of years earlier.

CONCLUSION

Although it is technically feasible to implant the pacemaker lead into the left ventricle via a patent foramen ovale, we consider this option to be obsolete for use with a biventricular pacemaker, due to the multitude of risks, which can, in part, be life-threatening for the patient.