Impact of operator experience and training strategy on procedural outcomes with leadless pacing: Insights from the Micra Transcatheter Pacing Study

Outcomes of leadless pacemaker implantation following transvenous lead extraction in high-volume referral centers: Real-world data from a large international registry

BACKGROUND

Limited data on the real-world safety and efficacy of leadless pacemakers (LPMs) post-transvenous lead extraction (TLE) are available.

OBJECTIVE

The purpose of this study was to assess the long-term safety and effectiveness of LPMs following TLE in comparison with LPMs de novo implantation.

METHODS

Consecutive patients who underwent LPM implantation in 12 European centers joining the International LEAdless PacemakEr Registry were enrolled. The primary end point was the comparison of LPM-related complication rate at implantation and during follow-up (FU) between groups. Differences in electrical performance were deemed secondary outcomes.

RESULTS

Of the 1179 patients enrolled, 15.6% underwent a previous TLE. During a median FU of 33 (interquartile range 24-47) months, LPM-related major complications and all-cause mortality did not differ between groups (TLE group: 1.6% and 5.4% vs de novo group: 2.2% and 7.8%; P = .785 and P = .288, respectively). Pacing threshold (PT) was higher in the TLE group at implantation and during FU, with very high PT (>2 V@0.24 ms) patients being more represented than in the de novo implantation group (5.4% vs 1.6 %; P = .004). When the LPM was deployed at a different right ventricular (RV) location than the one where the previous transvenous RV lead was extracted, a lower proportion of high PT (>1-2 V@0.24 ms) patients at implantation, 1-month FU, and 12-month FU (5.9% vs 18.2%, P = .012; 3.4% vs 12.9%, P = .026; and 4.3% vs 14.5%, P = .037, respectively) was found.

CONCLUSION

LPMs showed a satisfactory safety and efficacy profile after TLE. Better electrical parameters were obtained when LPMs were implanted at a different RV location than the one where the previous transvenous RV lead was extracted.

A leadless pacemaker in the real-world setting: Patient profile and performance over time

Background

While prior Micra trials demonstrated a high implant success rate and favorable safety and efficacy results, changes in implant populations and safety over time is not well studied. The objective of this analysis was to report the performance of Micra in European and Middle Eastern patients and compare to the Micra Investigational Device Exemption (IDE) and Micra Post Approval Registry (PAR) studies.

Methods

The prospective, single-arm Micra Acute Performance European and Middle Eastern (MAP EMEA) registry was designed to further study the performance of Micra in patients from EMEA. The primary endpoint was to characterize acute (30-day) major complications. Electrical performance was analyzed. The major complication rate through 12 months was compared with the IDE and PAR studies.

Results

The MAP EMEA cohort (n = 928 patients) had an implant success rate of 99.9% and were followed for an average of 9.7 ± 6.5 months. Compared to prior studies, MAP EMEA patients were more likely to have undergone dialysis and have a condition which precluded the use of a transvenous pacemaker (p < .001). Within 30 days of implantation, the MAP EMEA cohort had a major complication rate of 2.59%. Mean pacing thresholds were low and stable through 12 months (0.61 ± 0.40 V at 0.24 ms at implant and 12 months). Through 12 months post-implantation, the major complication rate for MAP EMEA was not significantly different from IDE (p = .56) or PAR (p = .79).

Conclusion

Despite patient differences over time, the Micra leadless pacemaker was implanted with a high success rate and low complication rate, in-line with prior reports.

Leadless transcatheter pacemaker: Indications, implantation technique and peri-procedural patient management in the Italian clinical practice

BACKGROUND

Safety and efficacy of leadless pacemakers (L-PM) have been demonstrated in multiple clinical trials, but real-world data on patient selection, implantation technique, and peri-procedural patient management in a clinical practice setting are lacking.

METHODS

Consecutive patients undergoing L-PM implantation in 14 Italian centers were followed in a prospective, multicentre, observational project. Data on baseline patient characteristics, clinical indications, implantation procedure, and peri-procedural patient management were collected. The rate and nature of device-related complications were also recorded.

RESULTS

A total of 782 L-PM patients (68.4% male, 75.6 ± 12.4 years) were included in the analysis. The main patients-related reason leading to the choice of implanting a L-PM rather than a conventional PM was the high-risk of device infection (29.5% of cases). The implantation success rate was 99.2%. The median duration of the procedure was 46 min. In 90% of patients the device was implanted in the septum. Of patients on oral anticoagulant therapy (OAT) (n = 498) the implantation procedure was performed without interrupting (17.5%) or transiently interrupting OAT without heparin bridging (60.6%). During a median follow-up of 20 months major device-related complications occurred in 7 patients (0.9%): vascular access-site complications in 3 patients, device malfunction in 2 patients, pericardial effusion/cardiac tamponade in one patient, device migration in one patient.

CONCLUSIONS

In the real world setting of Italian clinical practice L-PM is often reserved for patients at high-risk of infection. The implantation success rate was very high and the risk of major complications was low. Peri-procedural management of OAT was consistent with available scientific evidence.

Performance of transcatheter pacing system use in relation to patients' age

PURPOSE

Real-world safety data on the use of transcatheter pacing systems particularly in very elderly patients is still limited. The aim of this analysis was to investigate the effect of age on the safety and efficacy of leadless pacemaker implant.

METHODS

From May 2016 through July 2019, 577 patients were implanted with a leadless single-chamber pacemaker according to current pacing indication in 15 Italian cardiologic centers. The population was divided into age quartiles for evaluation, including (1) < 70 years, (2) 70-77 years, (3) 78-83 years, and (4) ≥ 83 years. Procedural data, complications, and electrical parameters were collected at baseline and during the follow-up.

RESULTS

Procedural-related complication occurrence was very low (< 1.0%) and similar in the four subgroups according to age even if the older patients were more frail. No cardiac tamponade was reported. Among the groups, no difference was observed in procedural time, fluoroscopy time duration, and electrical parameters (mean pacing impedance: 750 ± 192 and 599 ± 156, mean pacing threshold: 0.7 ± 0.5 and 0.7 ± 0.6, and mean right ventricular sensing 10.7 ± 6.1 and 11.5 ± 4.8 at implant and last follow-up, respectively).

CONCLUSIONS

The reported data demonstrated a high degree of safety during leadless implant across all patient ages. Procedural complications and device electrical measurements were similar among the different ages.

Difficulty removing a leadless pacemaker in a post-transfusion patient

A 99-year-old woman with atrial fibrillation bradycardia and symptomatic long pauses underwent a leadless pacemaker implantation after red blood cell transfusion due to anaemia. The patient's blood tests after transfusion showed hypercoagulability; haematocrit, haemoglobin and fibrinogen levels were increased from 24.5% to 33.2%, 76 g/L to 111g/L, and 346 mg/dL to 646 mg/dL, respectively. Blood tests showed no hereditary hypercoagulability disorder and she had no history of thrombophilia. A leadless pacemaker was implanted in the correct position in the right ventricle. Heparin was administered after sheath insertion and the leadless pacemaker system was thoroughly flushed with heparinised saline before the tether was cut; however, removing the tether after leadless pacemaker implantation was difficult because clots had formed on the tether.

Leadless pacemaker implantation quality: importance of the operator's experience

AIMS

Leadless cardiac pacemaker (PM) implantation differs from conventional PM implantation. While the procedure has been considered safe, recent real-world data raised concerns about the learning curve of new operators and their implantation quality. The goal of this study was to investigate the influence of the first operator's experience on leadless PM implantation quality and procedural efficiency.

METHODS AND RESULTS

We performed a bicentric analysis of all Micra TPS™ implantations in two large tertiary referral hospitals. We assessed both leadless PM implantation quality based on the absence of complications (requiring intervention or prolonged hospitalization), good electrical performance (pacing threshold ≤ 1.5 V/0.24 ms, R-wave amplitude > 5 mV), and acceptable fluoroscopy duration (<10 min) as well as procedural efficiency in relation to the operator's experience. Univariate and multivariate logistic regression analyses were performed to identify predictors for implantation quality and procedural efficiency. Leadless PM implantation was successful in 106/111 cases (95.5%). Three patients (2.7%) experienced acute complications (one cardiac tamponade, one femoral bleeding, one posture-related PM exit block). Multivariate analysis showed that implantation quality of more experienced first operators was higher [odds ratio 1.09 (95% confidence interval 1.00-1.19), P = 0.05]. Procedural efficiency increased with operator experience as evidenced by an inverse correlation of procedure time, time to the first deployment, fluoroscopy time, and the number of procedures performed (all P < 0.05).

CONCLUSION

The operator's learning curve is a critical factor for leadless PM implantation quality and procedural efficiency.

Peri-procedural management, implantation feasibility, and short-term outcomes in patients undergoing implantation of leadless pacemakers: European Snapshot Survey

The aim of this European Heart Rhythm Association (EHRA) prospective snapshot survey is to assess procedural settings, safety measures, and short-term outcomes associated with implantation of leadless pacemakers (LLPM), across a broad range of tertiary European electrophysiology centres. An internet-based electronic questionnaire (30 questions) concerning implantation settings, peri-procedural routines, complications, and in-hospital patient outcomes was circulated to centres routinely implanting both LLPMs and transvenous pacemakers (TV-PM). The centres were requested to prospectively include consecutive patients implanted with either LLPMs or TV-PMs during the 10-week enrolment period. Overall, 21 centres from four countries enrolled 825 consecutive patients between November 2018 and January 2019, including 69 (9%) implanted with LLPMs. Leadless pacemakers were implanted mainly under local anaesthesia (69%), by an electrophysiologist (60%), in the electrophysiology laboratory (71%); 95% of patients received prophylactic antibiotics prior to implantation. Most patients on chronic oral anticoagulation were operated on-drug (35%), or during short-term (to 48 h) drug withdrawal (54%). Implantation was successful in 98% of patients and the only in-hospital procedure-related complication was groyne haematoma in one patient. This EHRA snapshot survey provides important insights into LLPM implantation routines and patient outcomes. These findings suggest that despite the unfavourable clinical profile of pacemaker recipients, LLPM implantation is associated with relatively low risk of complications and good short-term outcomes.

Individualized left anterior oblique projection based on pigtail catheter visualization facilitates leadless pacemaker implantation

BACKGROUND

Pacemaker positioning on the right ventricular (RV) septum during implantation is conventionally conducted utilizing two fixed fluoroscopy angles, a 45° left anterior oblique (LAO) and 35° right anterior oblique projection. However, placement location can be suboptimal, especially for leadless pacemakers (LPMs).

OBJECTIVE

To evaluate the safety and ease of LPM implantation using individualized LAO projection.

METHODS

Consecutive patients undergoing LPM implantation were prospectively included. The angle of the RV septum was recorded for each patient by studying the angle at which an RV pigtail catheter (RV-PC) could be seen edge on. This was then used as the preferred LAO projection angle for that patient. We evaluated the success rate and safety of this method. We also compared the RV septum angle as measured by this method versus that measured by chest CT.

RESULTS

Of the 31 patients (mean age 80.6 ± 7.0 years, 15 females), LPM implantation was successful in 30. The pacemaker was implanted on the RV septum in 29 and on the free wall in one. LPM implantation was abandoned for anatomical reasons in one. Complications were limited to a groin arteriovenous fistula and one deep vein thrombosis. The angle of RV septum as measured by pigtail catheter and chest CT was not significantly different (CT: 54.8 ± 6.0°, RV pigtail catheter: 52.9 ± 6.1°, P = .07).

CONCLUSIONS

Using an RV-PC to determine the preferred angle of LAO projection facilitates differentiation between the RV septum and free wall, which in turn facilitates optimal LPM placement.

Tortuous inferior vena cava with severe scoliosis: An impediment to successful leadless pacemaker implantation

Both a multicenter cohort and a post-approval registry of the Micra™ transcatheter pacemaker (Medtronic, Minneapolis, MN, USA) reported high successful implantation rates (>99%) with long-term stability of electrical performance and long-term safety. Therefore, there has been little discussion on the causes of cases of failure in terms of anatomical findings. We report a case of failure of implantation of the Micra because of a tortuous inferior vena cava (IVC) secondary to severe scoliosis. A retrospective assessment of 3D reconstructed computed tomography imaging could visualize the configuration of the IVC-right atrium junction. A preprocedural anatomical assessment may help to predict the implantability of the transcatheter leadless pacemaker or to image the manipulation of the delivery catheter. <Learning objective: The Micra™ leadless pacemaker had high successful implantation rates (>99%). There has been little discussion on the causes of cases of failure in terms of anatomical findings. We report a case of failure of implantation of the Micra device because of a tortuous inferior vena cava secondary to severe scoliosis. A preprocedural 3D reconstructed computed tomography may help to predict the procedural difficulty of the Micra implantation or to image a manipulation of the delivery catheter.>.

Leadless pacemaker versus transvenous single-chamber pacemaker therapy: peri-procedural aspects, utilization of medical resources and patient acceptance

BACKGROUND

Leadless pacemaker (L-PM) have been developed in order to overcome the lead- and pocket-related complications associated with transvenous pacemaker (T-PM). The impact of L-PM implantation on the utilization of medical resources, patient comfort and therapy acceptance could differ from that of T-PM.

RESEARCH DESIGN AND METHODS

Prospective, single-center study enrolling 243 consecutive patients undergoing PM implantation. Propensity matching for baseline characteristics yielded 77 matched pairs. Procedural data, patient acceptance (assessed by Florida Patient Acceptance Survey, FPAS) and quality of life (QoL) (assessed at the baseline, 1 week, 3 and 6 months) were compared between the two groups (L-PM and T-PM).

RESULTS

The implantation procedure was longer in L-PM than T-PM patients (42.2±16.3 vs. 28.9±11.9 minutes; p<0.001). L-PM was associated with lower intra- and post-operative pain intensity (all p<0.05), shorter hospitalization (3.2±0.5 vs. 3.5±1.1 days; p=0.034), greater patient acceptance (FPAS score: 58.7±7.1 vs. 40.5±4.1; p<0.001), and better QoL on both physical and mental health scales (all p<0.05).

CONCLUSIONS

Although L-PM implantation takes longer than T-PM, it is better tolerated and accepted by patients and is associated with a better QoL.

Clinical outcomes of leadless pacemaker: a systematic review

INTRODUCTION

Transvenous pacemakers are associated with a significant amount of complications. Leadless pacemakers (LP) are emerging as an alternative to conventional devices. This article provides a systematic review of patient eligibility, safety and clinical outcomes of the LP devices.

EVIDENCE ACQUISITION

A systematic search for articles describing the use of LP was conducted. Out of two databases, 24 articles were included in the qualitative analysis. These articles comprised a total of 4739 patients, with follow-up times of 1-38 months. Further information was obtained from 10 more studies.

EVIDENCE SYNTHESIS

From a population of 4739 patients included in the qualitative analysis, 4670 LP were implanted with success (98.5%). A total of 248 complications were described (5.23%) during the follow-up. The most common were pacing issues such as elevated thresholds, dislodgements or battery failure (68 patients), events at the femoral access site such as hemorrhage, hematoma or pseudoaneurysms (64 patients) and procedure related cardiac injuries such as cardiac perforation, tamponade or pericardial effusion (47 patients). There were 360 deaths during the follow-up and 11 were described as procedure or device related. Four studies presented the strategy of using a combined approach of atrioventricular node ablation (AVNA) and LP implantation.

CONCLUSIONS

Leadless pacemakers seem to have a relatively low complication rate. These devices may be a good option in patients with an indication for single-chamber pacing, in patients with conditions precluding conventional transvenous pacemaker implantations. Studies directly comparing LP and transvenous pacemakers and data on longer follow-up periods are needed.

Outcomes using a single tapered dilator for Micra leadless pacemaker implant

Objectives

Comparison of outcomes, device deployment time (DT), and total time (TT) using a single tapered Coons dilator versus sequential serial dilation for implantation of the Micra leadless pacemaker.

Background

Micra leadless pacemaker placement requires a 23 French Micra introducer sheath (MIS) for percutaneous delivery. We sought to evaluate outcomes with use of a single tapered Coons dilator (CD) versus sequential serial dilatation (SD) method to facilitate insertion of the Micra introducer sheath.

Methods

35 patients were included in the SD arm and 49 in the CD arm. DT and TT were recorded in minutes and cost in dollars. Analysis was performed using independent t-test between two groups and one-way ANOVA to evaluate inter-operator variability in the CD arm.

Results

Both DT and TT were significantly lower for the CD arm (15.1 ± 5.1 vs 23.5 ± 9.3, p < 0.0005 and 29.9 ± 14 vs 39.3 ± 13.5 min, p = 0.000374; respectively). The cost was also significantly lower using a CD versus SD. There was no inter-operator variability in the CD arm between 6 operators (p = 0.177 for DT and p = 0.304 for TT). No complications occurred in the SD arm. There were 3 vascular access site complications in the CD arm, all of which occurred early in the operator’s experience.

Conclusion

Coons dilator is an efficient and cost-effective method for vascular dilatation to facilitate Micra leadless pacemaker insertion. Rate of complications is low and expected to improve with greater experience.

Leadless Pacemakers: State of the Art and Future Perspectives

Leadless pacemaker therapy is a new technology that aims at avoiding lead- and pocket-related complications of conventional transvenous and epicardial pacing. To date, 2 self-contained leadless pacemakers for right ventricular pacing have been clinically available: the Nanostim Leadless Pacemaker System and the Micra Transcatheter Pacing System. Additionally, a new multicomponent leadless pacemaker for endocardial left ventricular pacing has been proposed as an alternative choice for cardiac resynchronization therapy. In this review, we describe the state of the art of leadless pacing and compare the currently available devices with traditional transvenous leadless pacemakers.

Leadless pacing

Leadless self-contained intracardiac pacemakers were developed with the aim of abolishing the short- and long-term risk of lead- and pocket-related complications associated with transvenous devices. Leadless pacemakers promise minimally invasive procedures, long battery lives, and small amounts of foreign materials in the body. Experiences with the pioneering single-chamber devices have provided reasons for optimism about the future of the leadless concept. In the future, as more patients receive and live longer with implantable devices, the total risk of procedure- and lead-related complications is expected to increase, adding a sense of urgency to the need for leadless alternatives to transvenous pacemakers. This review surveys the performance of currently available leadless pacemakers as well as emerging new innovative adaptations and applications of the leadless concept.

Initial experience with a leadless pacemaker (Micra™) implantation in a low volume center in South East Asia

Aim:

The Micra™ Transcatheter Pacing System is a leadless pacemaker that has been introduced recently. We share our experience in a low volume center and the use of right ventricular angiography (RVA) during implantation.

Materials & methods:

Patients underwent Micra implantation and RVA was performed to predetermine the implant site.

Results:

Nine patients underwent Micra implantation. The most common indication was atrial fibrillation with bradycardia. The device was implanted at apical-septum in seven and mid-septum in two. The procedure time ranged from 30 to 100 min and fluoroscopic time 4–18 min. Pacing parameters remained stable after 1-month follow-up.

Conclusion:

The Micra implantation technique can be easily learnt. RVA was helpful in selecting an appropriate site for the Micra implant.

Development of simulation combining a physical heart model and three-dimensional system for electrophysiology training

BACKGROUND

A new three-dimensional heart anatomical simulator (3D HAS) has been created combining a physical heart model with an electroanatomic mapping (EAM) system. The aim of this study is to describe the development and the validation process of this device.

METHODS

We developed the 3D HAS combining a physical heart model with an EAM system. This simulator was then validated by 10 electrophysiologists, subdivided in two groups based on their experience in electrophysiology procedures. The performance of the experts was compared to the one of the novices in achieving three different tasks: fluoroless reconstruction of the right atrium, coronary sinus cannulation, and deployment of a linear ablation lesion in the cavotricuspid isthmus. For each operator, a score was calculated based on objective parameter for each task and for the overall performance.

RESULTS

The 3D HAS was located in an environment that allowed use of the main features of the EAM system including contact force sensing. No technical issue was encountered during the validation process. The experts' performance was significantly better than the one of the novices both overall (P = 0.009) and in each task (right atrium reconstruction, P = 0.016; coronary sinus cannulation, P = 0.008; ablation lesion, P = 0.03).

CONCLUSIONS

The 3D HAS is reliable and allows use of the main features of an EAM system in the right atrium. The ability to discriminate different levels of experience suggests that this simulator is enough realistic and could be useful for electrophysiology training.

The learning curve associated with the implantation of the Nanostim leadless pacemaker

Purpose

Use of novel medical technologies, such as leadless pacemaker (LP) therapy, may be subjected to a learning curve effect. The objective of the current study was to assess the impact of operators’ experience on the occurrence of serious adverse device effects (SADE) and procedural efficiency.

Methods

Patients implanted with a Nanostim LP (Abbott, USA) within two prospective studies (i.e., LEADLESS ll IDE and Leadless Observational Study) were assessed. Patients were categorized into quartiles based on operator experience. Learning curve analysis included the comparison of SADE rates at 30 days post-implant per quartile and between patients in quartile 4 (> 10 implants) and patients in quartiles 1 through 3 (1–10 implants). Procedural efficiency was assessed based on procedure duration and repositioning attempts.

Results

Nanostim LP implant was performed in 1439 patients by 171 implanters at 60 centers in 10 countries. A total of 91 (6.4%) patients experienced a SADE in the first 30 days. SADE rates dropped from 7.4 to 4.5% (p = 0.038) after more than 10 implants per operator. Total procedure duration decreased from 30.9 ± 19.1 min in quartile 1 to 21.6 ± 13.2 min (p < 0.001) in quartile 4. The need for multiple repositionings during the LP procedure reduced in quartile 4 (14.8%), compared to quartiles 1 (26.8%; p < 0.001), 2 (26.6%; p < 0.001), and 3 (20.4%; p = 0.03).

Conclusions

Learning curves exist for Nanostim LP implantation. Procedure efficiency improved with increased operator experience, according to a decrease in the incidence of SADE, procedure duration, and repositioning attempts.

Electronic supplementary material

The online version of this article (10.1007/s10840-018-0438-8) contains supplementary material, which is available to authorized users.

Successful implantation of a Micra leadless pacemaker via collateral femoral vein and inferior vena cava filter

This case details the successful implementation of a leadless pacemaker device in a patient with multiple venous occlusions and an IVC filter. As the incidence of IVC filters increases in patients with dysrhythmias, further investigations are required to determine the risk and safety of leadless pacemaker placement in this population.