Thrombotic complications with pacemakers

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.

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.

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).

Are Endovascular Interventions for Central Vein Obstructions due to Cardiac Implanted Electronic Devices Effective?

Objective: One of the late-onset complications of cardiac implanted electronic devices (CIEDs) is central venous obstruction (CVO). The aim of this study was to investigate the feasibility, efficacy, and safety of endovascular treatment of CIED-related CVOs.

Methods:Eighteen patients who underwent endovascular management of their device-related CVO were reviewed. Patients were classified into three groups: Group I patients were asymptomatic and needed lead replacement; Group II patients presented with symptomatic CVO without lead dysfunction, and Group III patients were referred with both symptomatic CVO and lead dysfunction. A treatment strategy involved recanalization and balloon angioplasty for Group I and angioplasty/stents for Groups II and III. Technical success, clinical success, complications, and long-term follow-up were assessed.

Results: Thirteen patients were in Group I, four in Group II, and one in Group III. Technical and clinical success was achieved in 17 patients (94%). No major complications were reported. Restenosis was observed in two patients at 40 and 42 weeks of follow-up, and these patients were successfully treated with angioplasty.

Conclusion: Endovascular management of CVO due to CIED is a safe and efficient technique. Plain balloon angioplasty is sufficient for lead replacement purposes, while stenting is needed for symptomatic CVO to achieve good long-term patency.

Mobile thrombus on cardiac implantable electronic device leads of patients undergoing cardiac ablation: incidence, management, and outcomes

PURPOSE

The rates of cardiovascular implantable electronic device (CIED) implantations and cardiac ablation procedures are increasing worldwide. To date, the management of CIED lead thrombi in the peri-ablation period remains undefined and key clinical management questions remained unanswered. We sought to describe the clinical course and management strategies of patients with a CIED lead thrombus detected in the peri-ablative setting.

METHODS

We performed a retrospective analysis of all patients who underwent a cardiac ablation procedure at Mayo Clinic Rochester from 2000 to 2014. Patients were included in our study cohort if they had documented CIED lead thrombus noted on peri-ablation imaging studies. Electronic medical records were reviewed to determine the overall management strategy, outcomes, and embolic complications in these patients.

RESULTS

Our overall cohort included 1833 patients, with 27 (1.4 %) having both cardiac ablation procedures as well as CIED lead thrombus detected on imaging. Of these 27 patients, 21 were male (77 %), and the mean age was 59.2 years. The mean duration of follow-up was 16.5 months (range 3 days-48.3 months). Anticoagulation was an effective therapeutic strategy, with 11/14 (78.6 %) patients experiencing either resolution of the thrombus or reduction in size on re-imaging. For atrial fibrillation ablation, the most common management strategy was a deferment in ablation with initiation/intensification of anticoagulation medication. For ventricular tachycardia ablations, most procedures involved a modified approach with the use of a retrograde aortic approach to access the left ventricle. No patient had any documented embolic complications.

CONCLUSIONS

The incidence of lead thrombi in patients undergoing an ablation was small in our study cohort (1.4 %). Anticoagulation and deferral of ablation represented successful management strategies for atrial fibrillation ablation. For patients undergoing ventricular tachycardia ablation, a modified approach using retrograde aortic access to the ventricle was successful. In patients who are not on warfarin anticoagulation at the time of thrombus detection, we recommend initiation of this medication, with a goal INR of 2-3. For patients on warfarin at the time of thrombus detection, we recommend an intensification of anticoagulation with a goal INR of 3.0.

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.

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.

Extraction of cardiac rhythm devices: indications, techniques and outcomes for the removal of pacemaker and defibrillator leads

Cardiac rhythm management devices (pacemakers) are being increasingly implanted worldwide not only for symptomatic bradycardia, but also for the management of arrhythmia and heart failure. Their use in more elderly patients with significant comorbidities is rising steeply and consequently long-term complications are increasingly arising. Such an increase in device therapy is being paralleled by an increase in the requirement for system extraction. Safe lead extraction is central to the management of much of the complications related to pacemakers. The most common indication for lead extraction is system infection Adhesions in chronically implanted leads can become major obstacles to safe lead extraction and life-threatening bleeding and cardiac perforations may occur. Over the last 20 years, specific tools and techniques for transvenous lead extraction have been developed to assist in freeing the lead body from the adhesions. This article provides a comprehensive review of the indications, tools, techniques and outcomes for transvenous lead extraction. The success rate largely depends on the time from implant. Up to 12 months from implant, it is rare that traction alone will not suffice. For longer lead implant duration, no single technique is sufficient to address all extractions, but laser provides the best chance of extracting the entire lead. Operator experience is vital in determining success as familiarity of a wide array of techniques will increase the likelihood of uncomplicated extraction. Long implantation time, lack of operator experience, ICD lead type and female gender are risk factors for life-threatening complications. Lead extraction should therefore, ideally be performed in high volume centres with experienced staff and on-site support from a cardiothoracic surgical team able to deal with bleeding complications from cardiovascular perforation.

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.

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.

Is radiologic placement of an arm port mandatory in oncology patients?

BACKGROUND

The objective of the current study was 2-fold: to evaluate a radiologically placed percutaneous arm port device (PRAPD) in a large series of 1000 consecutive cancer patients undergoing chemotherapy (in terms of safety, efficacy, complications, and quality of life [QoL]) and to propose future recommendations.

METHODS

From 1998 to August 2002, all patients who had cancer required chemotherapy underwent insertion of a PRAPD and were prospectively included. All patients were followed for technical feasibility, overall device-related complications, and QoL.

RESULTS

Technical failures (6.3%) were caused by the inability to perform an arm venogram in 22 patients or to catheterize the brachial vein in 41 patients. Septic complications (3.2%) included septicemia (n = 7 patients), catheter sepsis (n = 9 patients), and febrile neutropenia (n = 16 patients). Mechanical complications (4%) included a twisted port (n = 2 patients), extravasation (n = 7 patients), catheter leaks (n = 7 patients), port obstruction (n = 7 patients), skin dehiscence of the port (n = 11 patients), catheter rupture and occlusion (n = 5 patients), and median nerve compression (n = 1 patient). Central venous thrombosis occurred in 12 patients (1.2%), and arm phlebitis occurred in 7 patients (0.7%). Procedure-related death occurred in 0.4%. Early port removal was performed in 5.3% of patients. Good QoL was reported at port removal.

CONCLUSIONS

The PRAPD was found to be safe, effective, and well tolerated in oncology patients. PRAPD could be recommended in selected patients instead of a surgical port device.

Incidence and Risk Factors of Early Venous Thrombosis Associated with Permanent Pacemaker Leads

INTRODUCTION

Pacemaker lead implantation can cause thrombosis, which can be associated with serious local morbidity and complicated by pulmonary embolism. Few reliable estimates of the incidence of thrombosis have been reported. The contribution of established risk factors to venous thrombosis in patients with implanted pacemaker leads is unknown.

METHODS AND RESULTS

One hundred forty-five consecutive patients n = 145) underwent routine clinical and Doppler ultrasound evaluation for thrombosis before and 3, 6, and 12 months after lead implantation. Established risk factors for venous thrombosis were assessed in detail for all patients. Clinical outcome, including clinically manifest thrombosis, pulmonary embolism, associated pacemaker lead infection, complicated reinterventions, and death, was evaluated. Thrombosis was observed in 34 (23%) of 145 patients. Thrombosis did not cause any signs or symptoms in 31 patients but resulted in overt clinical symptoms in 3 patients. The absence of anticoagulant therapy, use of hormone therapy, and a personal history of venous thrombosis were associated with an increased risk of thrombosis. The risk of thrombosis increased in the presence of multiple pacemaker leads compared to a single lead.

CONCLUSION

Established risk factors for venous thrombosis and the presence of multiple pacemaker leads contribute substantially to the occurrence of thrombosis associated with permanent pacemaker leads. Risk factor assessment prior to implantation may be useful for identifying patients at risk for thrombotic complications. Preventive management in these patients is warranted.

Venous occlusion of the access vein in patients referred for lead extraction: influence of patient and lead characteristics

The aim of this study was to determine the effect of patient and lead characteristics on occlusion of the access vein in pacemaker and ICD patients. Contrast venography of the access vein was obtained in 89 patients (17 patients with an ICD) scheduled for lead extraction. The indication for extraction was infection in 57 patients (systemic infection in 9) and lead malfunction in 32 patients. In 6 of the 89 patients, leads were introduced in both the right and left subpectoral area, resulting in a total of 95 venous entry sites. In 22 of these entry sites one lead was present, in 61 two leads, in 11 three, and in 1 four leads. The vessel patency was graded open or occluded. Occlusion of the subclavian vein occurred in four (13%) patients with lead malfunction versus 18 (32%) patients with infection (P = 0.07). In patients with systemic infection, 5 of 9 showed venous occlusion (P = 0.01 when compared to patients with malfunction, odds ratio 8.75, 95% confidence interval 1.21-64.11). Considered per entry site, the incidence of occlusion was 7 of 22 with one lead present, 17 of 61 with two leads, 0 of 11 with three leads, and 0 of 1 with four leads (P = 0.13). No patient had a superior vena caval occlusion. Patients with systemic infection have an increased risk of occlusion of the access vein. On the contrary, the study found no support for the concept that the risk of venous occlusion increases with a higher number of leads present.

Exchange of pacing or defibrillator leads following laser sheath extraction of non-functional leads in patients with ipsilateral obstructed venous access

Occlusion of the subclavian or brachiocephalic vein in pacemaker or defibrillator patients prohibits ipsilateral implantation of new leads with standard techniques in the event of lead malfunction. Three patients are presented in whom laser sheath extraction of a non-functional lead was performed in order to recanalise the occluded vein and to secure a route for implantation of new leads. This technique avoids abandoning a useful subpectoral site for pacing or defibrillator therapy. The laser sheath does not affect normally functioning leads at the same site.

Long-term outcome of patients with multiple (> or = 3) noninfected transvenous leads: a clinical and echocardiographic study

To prospectively assess the incidence and clinical significance of thromboembolic complications in patients with multiple (> or = 3) noninfected transvenous leads; 48 consecutive patients were evaluated. Half of the patients had two ventricular leads and one atrial lead, 15 patients had two atrial leads and one ventricular lead, while 9 patients had two ventricular and two atrial leads. No additional care was provided except for aspirin (80 mg bid) and annually performed echo-Doppler studies. Clinical follow-up included signs and symptoms of subclavian and/or axillary vein thrombosis, the presence of right congestive heart failure, the number of hospital admissions, and death. Echo-Doppler studies assessed the presence of an enlarged right atrium or ventricle, right atrial or ventricular spontaneous contrast, and the presence of tricuspid regurgitation. During a total follow-up of 7.4 +/- 2.2 years there were no differences in the incidence of clinical variables as compared to age-matched controls with DDD pacemakers. The most common complication was transient venous thrombosis (mostly presenting as venous prominence 1-2 weeks after implantation), which was seen in 17% of the study group versus 15% in controls (NS). Cumulative mortality was not different in both groups (13% in the study group vs 15% in controls). No differences were present with respect to hospital admissions (1.1 +/- 0.27/year in the study group vs 1.2 +/- 0.30/year in the controls). In patients with multiple ventricular leads, tricuspid regurgitation on echo-Doppler studies was more frequent (24%) as compared to controls (4%); however, clinical signs of right heart failure were equally distributed. Thus, patients with multiple (> or = 3) noninfected leads have no clinical adverse outcome during long-term follow-up.

Assessment of the subclavian vein in patients with transvenous pacemaker leads

Thrombosis of the subclavian vein can occur after the implantation of transvenous pacemaker electrodes. Although this is seldom followed by thromboembolic complications, it can cause problems when replacing the leads. To assess the impact of the pacemaker leads on the subclavian vein, a study using noninvasive duplex sonography was performed on 56 patients at an average of 41 months after the implantation. Forty-three percent of the patients were found to have a normal function of the subclavian vein, 46% developed pathological changes of the vessel wall, and 11% occluded. These changes rarely caused symptoms, and, therefore, had little clinical significance. Moreover, the occlusion rate was found independent of the patient's age, the patient's sex, the number of electrodes, the procedure of implantation, and even the time from implantation. As a result, the clinical diagnosis of occlusion is uncertain. Therefore, duplex sonography is recommended as an easy means of excluding a totally thrombosed subclavian vein prior to replacing pacemaker leads.

Long-term thrombosis after transvenous permanent pacemaker implantation

To assess the efficacy of prophylactic administration of anticoagulant and antiaggregant drugs to prevent venous thrombosis after long-term transvenous permanent pacemaker implantation, venograms were performed in 100 consecutive patients at the elective replacement of the pacemaker. Mean follow-up period after initial transvenous permanent pacemaker implantation was 6.0 years. The venograms demonstrated normal in 77 patients. The remaining 23 venograms showed venous stenosis in 11 patients and total obstruction in 12 patients. Twenty-one of these 23 patients had venous collateral circulation. No difference was found in the incidence of venous abnormalities according to the route of entry, the lead insulation, the total number of the implanted leads, and anticoagulant and antiaggregant drugs. All these patients have remained asymptomatic. In conclusion, the incidence of venous thrombosis after long-term transvenous pacing is 23% and the causes of venous thrombosis may be endothelial trauma and underlying venous stenosis. As this article describes a retrospective limited study, we cannot find the efficacy of prophylactic administration of anticoagulant and antiaggregant drugs to prevent venous thrombosis formation after transvenous permanent pacemaker implantation. Further prospective study will be needed to assess the efficacy of prophylactic administration of anticoagulant and antiaggregant drugs.

Extraction and replacement of permanent pacemaker leads through occluded vessels: use of extraction sheaths as conduits--balloon venoplasty as an adjunct

Patients (pts) may present for lead extraction with symptomatic or asymptomatic subclavian vein or superior vena cava thrombosis. Replacement of permanent pacemaker leads (PPLs) in these pts may be difficult and may require accessing a new site. We examined the utility of replacing PPLs through completely occluded vessels using extraction sheaths as conduits through the total occlusion. Over six years, a total of 210 atrial and/or ventricular PPLs were extracted from 137 pts. Two pts presented with angiographically documented thrombotic occlusion of the subclavian vein. One additional pt. who had presented with a superior vena cava (SVC) syndrome, had a totally occluded innominate vein and SVC occlusion. Balloon venoplasty was used as an adjunct to dilate the SVC. In all pts, after PPLs were removed via a subclavian extraction sheath through the occluded vessel, the retained sheath was used to place a guide wire, then a peel away dilating sheath, to insert new PPLs, in each case on the side of total venous occlusion. Seven PPLs and two lead fragments were extracted, and five new PPLs replaced, ipsilateral to the venous occlusion. These data show that extraction of PPLs through thrombosed veins may be performed successfully and may not require replacing the leads through a new site. This technique spares the pt the need to access the opposite subclavian vein, and it avoids an excessive number of PPLs in the subclavian vein and SVC. The procedure illustrates an efficient means to reintroduce new PPLs with the potential to reduce associated morbidity, since repeat puncture of the subclavian vein is not required. Safety of the procedure as a whole must be considered with regard to the known risks of lead extraction, some complications of which may be substantial using current techniques.

Risk factors for venous obstruction in children with transvenous pacing leads

To determine the incidence and risk factors for venous obstruction in children with transvenous pacing leads, 63 children were evaluated clinically and echocardiographically. Patients with abnormal clinical and/or echocardiographic findings were further investigated by venography. Thirteen patients (21%) had evidence of venous obstruction. Venography in 11 (2 refused) showed that severity of obstruction (as defined by percentage of luminal narrowing) was complete (100%) in 3, severe (> 90%) in 4, and moderate (60%-90%) in 5 (1 patient having 2 sites of obstruction). Risk factors for obstruction in 55 patients with single implantation procedures (10 with obstruction; 18%) were sought. Total cross-sectional area of lead(s) was indexed to body surface area at implantation (INDEX). Patients with obstruction had a higher mean INDEX (7.6 +/- 1.6 mm2/m2) than patients without obstruction (4.9 +/- 2.0 mm2/m2); P < 0.0002). Receiver-operator characteristic curves showed an INDEX > 6.6 mm2/m2 to best predict obstruction, with a sensitivity of 90% and specificity of 84%. Since pacing is lifelong, sizing of transvenous leads to the child is important to prevent obstruction and preserve venous access.

The treatment of septicemia in pacemaker patients

The authors analyzed the data of seven patients who had undergone open heart surgery because of pacemaker endocarditis in the past 4 years. Repeated surgical interventions on the pacemaker system were found to be the most common predisposing factors. Staphylococcus aureus and Staphylococcus epidermidis were the most common causative organisms. Two-dimensional echocardiography was important in the diagnosis of cases with atypical clinical picture and negative blood cultures. We concluded that: (1) any pacemaker patient with fever should be considered to have a pacemaker endocarditis; (2) all of these patients should be examined by two-dimensional echocardiography; and (3) the total removal of the infected hardware seems to be the only way to achieve complete recovery.

Subclavian vein anatomic subtypes defined by digital cinefluroscopic venography prior to permanent pacemaker lead insertion

Digital cinefluoroscopic venography of the subclavian vein was performed in 26 consecutive patients. The optimal stored image of the anticipated venipuncture site was magnified, road mapped, and used to compare with fluoroscopic-guided venipuncture. Two anatomic subtypes for both subclavian veins were observed. For the left subclavian vein, a gradual curve was seen most often (57%), while the remainder (43%) exhibited an "s"-shaped curve. For the right subclavian, a gradual curve was observed most frequently (60%) while an acute 90 degrees angle was noted in the remainder (40%). The "s"-shaped curve in the left subclavian vein necessitated redirection of the needle site both laterally and cranially. In three or 12% of patients venography showed either subclavian thrombosis or a persistent left superior vena cava and lead insertion was moved to the opposite side. Successful venipuncture and subsequent cannulation of the subclavian vein was achieved with the first or second passage of the needle in 22 or 85% of the 26 patients. Digital cinefluoroscopic venography appears to be both safe and rapid and may facilitate insertion of permanent pacemaker leads into the subclavian vein.

Budd-Chiari syndrome due to pacemaker-induced thrombosis

We report a unique case of Budd-Chiari syndrome caused by pacemaker leads-induced thrombosis. A 34 year old female patient was subjected to a permanent pacemaker insertion because of refractory paroxysmal supraventricular tachycardia attacks related to Wolff-Parkinson-White syndrome. Three years later, another pacemaker was re-implanted because of its dislodgement. Four episodes of skin infections at the implantation site were noted thereafter. The patient developed symptoms of abdominal pain and ascites 5 years after the second pacemaker implantation. Ultrasonography and computerized tomography of the abdomen revealed hepatomegaly with ascites and dilated inferior vena cava. An echocardiogram displayed thrombus formation in the superior vena cava, the right atrium and the inlet of the inferior vena cava into the right atrium. Inferior and superior venacavogram confirmed the above findings. With the impression that Budd-Chiari syndrome was caused by pacemaker-induced thrombus, we removed the pacemaker first and thoracotomy with thrombectomy was then performed. The clinical symptoms resolved after the operation. To our knowledge, this is the first case reported in the literature and this observation supported the thrombosis theory for membranous obstruction of inferior vena cava.

Multiplane transesophageal echocardiographic evaluation of transvenous defibrillation leads

Permanent transvenous cardioverter-defibrillator leads were investigated by multiplane transesophageal echocardiography (TEE) (1) to determine whether intracardiac lead segments can be visualized, (2) to verify the position of the coils, and (3) to detect possible thrombus formation. The diagnostic information obtained in 62 patients by TEE was compared to that of transthoracic echocardiography (TTE). Abnormal findings were only visualized by multiplane TEE. However, further controlled studies are needed to determine the clinical relevance of displaced caval (one patient) and ventricular coils (15 patients), ventricular (1 patient) or atrial (6 patients) loops, and of clinically uneventful thrombi (13 patients).

[Phlebitis of the upper limbs on pacemaker electrodes. 4 cases and review of the literature]

We report four cases of deep venous thrombosis of the upper extremity, which occurred in two women and two men (mean age 79 years) in whom a pacemaker electrode had been inserted 4 years on averages previously. In three of these four cases phlebitis developed after immobilization of the limb containing the electrode. Deep venous thrombosis of the upper extremity is rare, but 28% of catheterizations are responsible for phlebitis. One to 3% of patients fitted with a pacemaker have symptomatic phlebitis, but these figures rise to 28-65% when phlebography is systematically performed in subjects wearing a pacemaker. The clinical signs are the same as those of the classical forms, and the diagnosis is made by doppler-ultrasonography and by phlebography which informs on the collateral circulation. Cure is obtained with efficient anticoagulant therapy. These cases prompt us to prescribe a preventive subcutaneous heparin therapy in those pacemaker-fitted subjects whose arm is immobilized. The heparin dosage remains to be determined precisely.

Pulmonary embolism from left subclavian vein thrombus following suprapubic prostatectomy

Deep venous thrombosis (DVT) of the axillary and subclavian veins accounts for approximately 1-2 percent of all recorded deep venous thrombosis. Pulmonary embolism from an upper extremity DVT has been reported to vary between 2 percent and 35.7 percent. We report the occurrence of a left subclavian vein DVT with subsequent nonfatal pulmonary embolism in a sixty-two-year-old patient twenty-four hours following suprapubic prostatectomy. A review of the literature is presented, along with pathophysiology, diagnosis, and treatment.

Venous complications after insertion of a transvenous pacemaker

We reviewed the incidence, clinical features, current diagnostic evaluations, and treatments of venous complications that can occur after implantation of a transvenous pacemaker. Of the approximately 80 published articles on the potential venous complications after implantation of a permanent transvenous pacemaker, we selected 63 that addressed the clinical features, diagnosis, and treatment of pacemaker lead-induced venous thrombosis, which occurs in approximately 30 to 45% of patients early or late after implantation of a transvenous pacemaker. Most patients with chronic deep venous thrombosis remain asymptomatic because of the development of an adequate venous collateral circulation. Clinical features of pacemaker lead-induced deep venous thrombosis, although rare, are easily recognized. They should be sought routinely during follow-up of all patients with transvenous pacemaker leads because venous obstruction can interfere with intravenously administered therapy, monitoring of central venous pressure, and revision of a pacemaker lead. Acute deep venous thrombosis is likely to be symptomatic. Early recognition and treatment of acute deep venous thrombosis may help to decrease the potential morbidity and mortality. The definitive diagnosis of pacemaker lead-induced venous thrombosis necessitates contrast-enhanced or digital subtraction venography. Management includes anticoagulation, thrombolytic therapy, surgical intervention, and, recently, percutaneous transluminal balloon venoplasty and depends on the duration, extent, and site of venous occlusion as well as the accompanying symptoms.

Transvenous placement of a pacemaker lead through an introducer despite long-standing subclavian-vein occlusion

Under ordinary circumstances complete chronic subclavian vein occlusion precludes using that vein for the pacemaker lead. There are circumstances, however, in which a patent vein beyond the obstruction can be reached with an introducer needle, thus permitting transvenous access similar to any other introducer-assisted implantation. A case exemplifying this point is described. Patency of the right subclavian vein beyond an occlusion was demonstrated by angiography, and a new dual-chamber pacemaker lead was inserted through that site by use of the introducer method.

Entrapment of tined leads

A rare complication is described, in three patients. The tined tip of a ventricular pacemaker electrode was entrapped in the chordae of the tricuspid valve and could not be removed by subtle manipulations in two patients. In one patient, the electrode was removed with partial rupture of the tricuspid valve. The two electrodes remained in the entrapped position and new electrodes were inserted in all three cases. No clinical sequelae were found during follow-up of at least 24 months.

Entanglement of embolised thrombus with an endocardial lead causing pacemaker malfunction and subsequent pulmonary embolism

A 67 year old woman with a permanent pacemaker was admitted with pulmonary oedema and mitral valve incompetence two months after a myocardial infarction. Echocardiograms showed good left ventricular function and a large coil of apparent thrombus in the right atrium prolapsing into the right ventricle. Intermittent loss of pacemaker sensing and capture was noticed on admission and probably caused the supraventricular tachycardia and ventricular fibrillation that occurred before an exploratory bypass operation. At operation rupture of the papillary muscle was found and the mitral valve was replaced. A large piece of thrombus was retrieved from the right pulmonary artery. The right heart contained no clot and the pacemaker wire was not displaced. It is envisaged that the strand of venous thrombus was caught in the permanent pacing wire at the tricuspid valve level resulting in an unusual case of pacemaker malfunction. The eventual poor outcome was almost certainly influenced by the arrhythmias and pulmonary embolism caused by the clot and might have been avoided by early operation.

Morphological changes in human myocardium during permanent pacing

We have reviewed 74 cases of patients with permanent pacing, using different types of pacing leads in order to determine what morphological changes are produced by this therapy. Macroscopic examination of the heart was performed and slides at the implantation site reviewed when available. Severe chronic inflammation, scarring and a myocardial response were the prominent findings. From a strictly morphological aspect, the initial trauma at implantation time, the chronic foreign body reaction and myocardial response to chronic trauma, are both much less significant in endovenous than in epimyocardial pacing.