Cranial vena caval syndrome secondary to transvenous pacemaker implantation in two dogs

2022 Update of the Consensus on the Rational Use of Antithrombotics and Thrombolytics in Veterinary Critical Care (CURATIVE) Domain 1- Defining populations at risk

OBJECTIVES

To expand the number of conditions and interventions explored for their associations with thrombosis in the veterinary literature and to provide the basis for prescribing recommendations.

DESIGN

A population exposure comparison outcome format was used to represent patient, exposure, comparison, and outcome. Population Exposure Comparison Outcome questions were distributed to worksheet authors who performed comprehensive searches, summarized the evidence, and created guideline recommendations that were reviewed by domain chairs. The revised guidelines then underwent the Delphi survey process to reach consensus on the final guidelines. Diseases evaluated in this iteration included heartworm disease (dogs and cats), immune-mediated hemolytic anemia (cats), protein-losing nephropathy (cats), protein-losing enteropathy (dogs and cats), sepsis (cats), hyperadrenocorticism (cats), liver disease (dogs), congenital portosystemic shunts (dogs and cats) and the following interventions: IV catheters (dogs and cats), arterial catheters (dogs and cats), vascular access ports (dogs and cats), extracorporeal circuits (dogs and cats) and transvenous pacemakers (dogs and cats).

RESULTS

Of the diseases evaluated in this iteration, a high risk for thrombosis was defined as heartworm disease or protein-losing enteropathy. Low risk for thrombosis was defined as dogs with liver disease, cats with immune-mediated hemolytic anemia, protein-losing nephropathy, sepsis, or hyperadrenocorticism.

CONCLUSIONS

Associations with thrombosis are outlined for various conditions and interventions and provide the basis for management recommendations. Numerous knowledge gaps were identified that represent opportunities for future studies.

A retrospective evaluation of the indications, complications, and outcomes associated with epicardial pacemakers in 20 cats from a single institution

INTRODUCTION

The objective of this retrospective study was to describe the indications, complications, and long-term outcomes in a group of cats that received an epicardial pacing (EP) system.

ANIMALS

Twenty client-owned cats.

MATERIALS AND METHODS

Medical records were reviewed for signalment, presenting complaint, primary electrocardiogram (ECG) diagnosis, presence of structural heart disease, presence of congestive heart failure (CHF), presence of major or minor complications, and survival time.

RESULTS

The majority of cats were presented for syncope (n = 11), and the most common ECG diagnosis was advanced second-degree atrioventricular block (n = 9). Fifteen cats (15/20, 75%) had one or more major or minor complications. One cat died in the perioperative period as a result of a major complication. None of the variables evaluated were associated with a statistically significant increase in the occurrence of major or minor complications. The most common major complication was loss of ventricular capture (seven instances in six cats), which was successfully treated in all cases by increasing pacemaker output or replacing both the lead and the pulse generator. The most common minor complications were arrhythmias (n = 7) and sensing issues (n = 8). The overall median survival time (MST) was 948 days. No statistical difference in survival time was identified between cats that experienced a major complication and those that did not.

CONCLUSIONS

Although complications were common in this feline population after EP, major and minor complications were successfully treated.

Optimizing single-chamber pacing in dogs Part 1: Rate determinations, rate interventions and hysteresis

Determining ideal pacing rates to meet physiological needs and optimizing programming to prevent unnecessary right ventricular pacing in dogs requires an understanding of heart rate profiles and applicable pacing technology. The heart rate and rhythm of the dog is complex necessitating investigation of rate requirements of activity and circadian influences. Overlaying this information are a multiplicity of other factors such as age, breed, temperament, cardiovascular disease and underlining rhythm disorders that contribute to the difficulty in making general conclusions. However, all such information permits better implementation of programming options with the goal of better outcomes. In this review (Part 1 of a two-part review) instantaneous heart rate, rolling average heart rate, simple average heart rate, heart rate tachograms, RR interval tachograms (2D, 3D and dynamic), and Poincaré plots (2D, 3D and dynamic) are discussed as they apply to decisions in the determination and examination of pacing rates for dogs programmed in the VVI pacing mode (Ventricular paced, Ventricular sensed, Inhibited pacing). The applicable pacing operations available for three pacemaker companies are reviewed (Abbott, Biotronik/Dextronix, and Medtronic). The programmable options considered include: slowest pacing rate without additional features to extend the pacing interval, sleep/rest rate preferences, hysteresis to lengthen pacing interval following intrinsic beats, and intermittent increases in pacing following abrupt loss of intrinsic rhythm. Recommendations are suggested for follow-up of individual dogs with examination of pacing statistics and Holter monitoring.

Cranial Vena Cava Syndrome in Guinea Pigs with Chronic Jugular Vein Catheters

Guinea pigs are a premier small animal model for infectious disease research, and chronic indwelling venous access ports may be used to facilitate various procedures. Here we report catheter-related lesions in 5 uninfected Dunkin-Hartley guinea pigs with chronic jugular vein catheters used for imaging studies. Three guinea pigs were found dead with no premonitory signs. At necropsy, there was severe bilateral pulmonary atelectasis due to 20 to 29 mL of pleural effusion resulting from catheter-related thrombosis and cranial vena cava syndrome. In addition, one of these 3 guinea pigs had a polymicrobial catheter infection with abscessation. A 4th clinically normal guinea pig was euthanized at the end of the study, having spontaneously lost its catheter 7 mo prior, and had 17 mL of pleural effusion. The 5th guinea pig was euthanized following pooling of contrast material around the distal catheter in the cranial vena cava on CT. By histology, affected animals had recent and remote thrombosis or fibrosis (or both) of the cranial vena cava and right atrial wall, with osseous and cartilaginous metaplasia. Cranial vena cava syndrome should be considered as a differential for dyspnea or death in chronically catheterized laboratory animals.

Use of rivaroxaban for treatment of cranial vena cava syndrome secondary to transvenous pacemaker lead thrombosis in a dog

A six-year-old Brussels griffon was presented for cervical swelling three months after implantation of a transvenous pacemaker. Transthoracic echocardiography demonstrated a thrombus associated with the pacemaker lead, partially obstructing right atrial inflow. The laboratory findings were consistent with protein-losing nephropathy. Initial medical therapy consisted of rivaroxaban (0.68 mg/kg orally every 24 hours), clopidogrel (2.5 mg/kg orally every 24 hours), and enalapril (0.5 mg/kg orally every 12 hours). Resolution of cervical and thoracic edema was noted within two weeks of initiating therapy. Recheck echocardiography two months and one year later revealed decreasing thrombus size despite worsening proteinuria. To the authors' knowledge, this is the first documented use of rivaroxaban for successful medical treatment of cranial vena cava syndrome caused by intracardiac pacemaker lead thrombosis in a hypercoagulable patient.

Retrospective Analysis of Indications and Complications Related to Implantation of Permanent Pacemaker: 25 Years of Experience in 31 Dogs

Introduction

Pacemaker implantation is the only effective symptomatic treatment for life-threatening bradyarrhythmias. Major complications observed after implantation of cardiac pacemakers include lead dislocation, loss of pulse generator function, and inadequate stimulation. The aim of this retrospective single-centre study was to analyse the indications for pacemaker implantation and the incidence and types of complications associated with this procedure in dogs treated for symptomatic bradyarrhythmia.

Material and Methods

The retrospective analysis included 31 dogs with symptomatic bradyarrhythmia, implanted with permanent cardiac pacemakers in 1992-2017. The list of analysed variables included patient age, breed, sex, indication for pacemaker implantation, comorbidities, and the incidence of procedure-related complications along with the type thereof.

Results

The most common indication for pacemaker implantation was 3^rd degree AVB, followed by SSS, advanced 2^nd degree AVB, and PAS. Pacemaker implantation was associated with a 35% overall complication rate and 6.45% periprocedural mortality. There were no significant differences in terms of procedure-related complications with regard to age, sex, breed, indications for pacemaker implantation, or comorbidities.

Conclusions

Cardiac pacing is the only effective treatment of symptomatic bradycardia, but as an invasive procedure, may pose a risk of various complications, including death.

Synchronous diaphragmatic contraction associated with dual-chamber transvenous pacing in a dog

A 3-year-old, 20-kg, spayed female, mix-breed dog received a dual-chamber pacemaker for management of symptomatic 3rd-degree atrioventricular block. Synchronous diaphragmatic contraction was documented to occur with atrial pacing. Various methods to reduce the occurrence of pacemaker-related phrenic nerve stimulation are discussed.

A retrospective review of 146 active and passive fixation bradycardia lead implantations in 74 dogs undergoing pacemaker implantation in a research setting of short term duration

Abstract

Background

Canine veterinary patients increasingly benefit from implantation of transvenous pacemakers for bradyarrhythmias. No published data exist examining procedural outcomes of pacemaker implantation performed in the preclinical laboratory. The purpose was to review short term complication, infection, dislodgement, penetration rates, plus overall morbidity following pacemaker implantation in the research setting. A retrospective review of 74 Class A purpose-bred mongrels implanted with active (n = 89) and passive fixation (n = 57) intracardiac leads for dual (n = 72) or single (n = 2) chamber pacing was performed.

Results

All leads were implanted successfully, meeting electrical implant criteria. Follow-ups typically occurred every 7 days (first month), then at 30 day intervals. Seroma formation was 1.4% and 10.8% at the venotomy and pulse generator site respectively. Overall infection rate was 1.4%. Overall dislodgement rate was 2.1%, (2 passive atrial leads, 1 passive ventricular lead). Overall fractures and insulation defects were zero. Two helix penetrations were noted incidentally post mortem, one at the right atrial appendage and one at the right ventricle (64 dogs, 128 leads evaluated), a 1.6% event rate. Major in-life adverse events were 5.4% (4 of 74 dogs), including 1 infection and 3 lead dislodgements.

Conclusions

This review demonstrates a low complication rate with bradycardia lead implants in the short term (up to 180 days), in a high volume research setting. Lead type, implant technique, surgeon experience, healthy patient population, patient size and follow-up care play a role. This review also suggests active fixation leads in the right atrial appendage of dogs are safe and reliable.

Electronic supplementary material

The online version of this article (10.1186/s12917-018-1431-2) contains supplementary material, which is available to authorized users.

Complication rates associated with transvenous pacemaker implantation in dogs with high-grade atrioventricular block performed during versus after normal business hours

Background

Transvenous pacemaker implantation in dogs is associated with a relatively high complication rate. At our institution, pacemaker implantation in dogs with high‐grade atrioventricular block (HG‐AVB) frequently is performed as an after‐hours emergency.

Hypothesis

Among dogs with HG‐AVB, the rate of major complications is higher when pacemakers are implanted after hours (AH) compared to during business hours (BH).

Animals

Client‐owned dogs with HG‐AVB that underwent transvenous pacemaker implantation between January 2002 and December 2012 at the North Carolina State University Veterinary Teaching Hospital.

Methods

Retrospective medical record review. Two‐year follow‐up was required for complications analysis.

Results

Major complications occurred in 14/79 dogs (18%) and included lead dislodgement, lead or generator infection, lead or generator migration, and pacing failure. Incidence of major complications was significantly higher AH (10/36, 28%) compared to BH (4/43, 9%; P = .041), and all infectious complications occurred AH. Median survival time for all dogs was 27 months and did not differ between AH and BH groups for either all‐cause (P = .70) or cardiac (P = .40) mortality. AH dogs were younger than BH dogs (P = .010), but there were no other clinically relevant differences between BH and AH groups in terms of demographic, clinical, or procedural variables.

Conclusions and Clinical Importance

At our institution, AH transvenous pacemaker placement is associated with a higher rate of major complications (especially infections) compared to BH placement. This difference may be because of a variety of human factor differences AH versus BH.

Acquired Tricuspid Valve Stenosis Associated with Two Ventricular Endocardial Pacing Leads in a Dog

Acquired tricuspid valve stenosis (TVS) is a rare complication of endocardial pacing lead implantation in humans that has only been described once previously in the veterinary literature in a dog with excessive lead redundancy. A 12 yr old terrier presented with right-sided congestive heart failure 6 mo after implantation of a second ventricular endocardial pacing lead. The second lead was placed due to malfunction of the first lead, which demonstrated abnormally low impedance. Transthoracic echocardiography identified hyperechoic tissue associated with the pacing leads as they crossed the tricuspid valve annulus as well as a stenotic tricuspid inflow pattern via spectral Doppler interrogation. Medical management was ultimately unsuccessful and the dog was euthanized 6 wk after TVS was diagnosed. The authors report the first canine case of acquired TVS associated with two ventricular endocardial pacing leads.

Diseases associated with thrombosis

Coagulation abnormalities are commonly encountered in critical illness. Traditionally, clinically relevant coagulation disorders have consisted mostly of bleeding associated with advanced stages of disseminated intravascular coagulation or toxin ingestion. However, advances in critical care have highlighted hypercoagulability as a clinically relevant state that must be recognized and treated to optimize the chances of a positive outcome. Retrospective studies of dogs with confirmed thrombosis in varying locations have identified populations most likely to experience hypercoagulable states. Diseases most frequently complicated by thrombosis include immune-mediated disease, neoplasia, systemic inflammation and sepsis, cardiac disease, protein-losing states, and infectious diseases. In this report, the existing retrospective studies will be discussed along with a review of specific disease processes that predispose to a hypercoagulable state. Studies targeting those populations most at risk for thrombotic complications are necessary for better understanding the need for prophylactic anticoagulant therapy.

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.