Clinical Impact of Baseline Right Bundle Branch Block in Patients Undergoing Transcatheter Aortic Valve Replacement

The electrocardiogram: Still a useful marker for LV fibrosis in aortic stenosis

Left ventricular (LV) strain on the electrocardiogram (ECG) (down-sloping, convex ST-segment depression with asymmetric T-wave inversion in leads V5 and V6) reflects fibrosis as a result of subendocardial ischemia. It is associated with a significantly increased risk of cardiovascular events independent of the presence of LV hypertrophy on the echocardiogram or cardiac magnetic resonance (CMR) scan. Ongoing studies of early aortic valve replacement in asymptomatic patients with severe aortic stenosis are using ECG changes as a marker of possible fibrosis shown by midwall late gadolinium enhancement on CMR. However, until these studies report, it is still reasonable to respond to LV strain on the ECG by tightening control of systemic hypertension and consider intervention in cases where indications are otherwise in borderline.

Arrhythmias in Relation to Mortality After Transcatheter Aortic Valve Replacement

BACKGROUND

The purpose of this study was to identify predictors of mortality and potentially modifiable factors related to arrhythmias in patients that undergo transcatheter aortic valve replacement (TAVR). Patients that undergo TAVR are at risk for complete heart block requiring pacemaker implant. Additionally, other arrhythmias, specifically atrial fibrillation (AF), are common in this population. It is unclear how arrhythmias and their management contribute to mortality risk.

METHODS

The study analyzed 176 patients who underwent TAVR at a single center. Factors associated with pacemaker implantation within 30 days were analyzed by logistic regression. Factors associated with mortality were analyzed by Kaplan-Meier and Cox regression analyses.

RESULTS

Mean age was 80 ± 8.5 years. AF was present in 69 patients, and 39 received anticoagulation. Post-TAVR, a pacemaker was implanted in 25 patients within 30 days. Over a follow up of 566 ± 496 days, 49 patients died. In multivariable analysis, right bundle branch block remained significant (odds ratio 4.212, P = 0.012) for pacemaker implant within 30 days. The AF (hazard ratio [HR] 3.905, P = 0.001), albumin level (HR 0.316, P = 0.034), and diabetes (HR 2.323, P = 0.027) were predictors of death in a multivariate analysis, while pacemaker implant within 30 days was not. Patients with AF who were anticoagulated had improved survival in a stratified Kaplan-Meier analysis compared with those who were not anticoagulated (P = 0.0001).

CONCLUSION

AF, diabetes, and low albumin levels are independently associated with mortality after TAVR. In particular, patients with AF who are not anticoagulated are at highest risk for death. Efforts to identify AF and consider anticoagulation should be emphasized.

The incidence and impact of cardiac conduction disturbances after transcatheter aortic valve replacement

Transcatheter aortic valve replacement (TAVR) has developed into an established therapy for patients with severe aortic stenosis (AS) across the spectrum of surgical risk. Despite improvements in transcatheter heart valve (THV) technologies and procedural techniques, cardiac conduction disturbances, including high degree atrioventricular block (AVB) requiring permanent pacemaker (PPM) implantation and new-onset left bundle branch block (LBBB), remain frequent complications. TAVR-related conduction disturbances occur due to injury to the conduction system from interactions with interventional equipment and the transcatheter valve stent frame. Risk factors for post-TAVR conduction disturbances have been identified and include clinical characteristics, baseline electrocardiogram findings (right bundle branch block), anatomic factors, and potentially modifiable procedural factors (type of transcatheter valve, depth of implantation, over-sizing). New-onset LBBB and PPM implantation after TAVR have been shown to be associated with adverse long-term clinical outcomes, including mortality and heart failure hospitalization. These clinical consequences are likely to be of increasing importance as TAVR is utilized in younger and lower risk population. This review provides an updated overview of the literature regarding the incidence, predictors, and clinical outcomes of TAVR-related conduction disturbances, as well as proposed strategies for the management of this frequent clinical challenge.

Timing and evolution of advanced conduction disturbances in patients with right bundle branch block undergoing transcatheter aortic valve replacement

Aims

This study sought to determine the timing and evolution over time of advanced conduction disturbances (CDs) in patients with baseline right bundle branch block (RBBB) undergoing transcatheter aortic valve replacement (TAVR).

Methods and results

One hundred and ten consecutive patients with pre-existing RBBB were included (out of 1341, 8.2%). All arrhythmias during the hospitalization period were recorded. Follow-up was performed at 30 days, 1 year, and yearly thereafter. Conduction recovery and ventricular pacing percentage (VPP) was evaluated at 30 days in those patients with permanent pacemaker implantation (PPMI). Sixty-one (55.5%) patients suffered advanced CDs [97% complete or high-degree atrioventricular block (CHB/HAVB)], and the vast majority (98%) occurred within the first 3 days post-procedure (intraprocedural: 85%). Fifty-two (47.3%) patients had PPMI (vs. 11.0% in non-RBBB patients, P < 0.001). Ventricular pacing percentage at 1 month was higher in patients with persistent-intraprocedural CHB/HAVB compared to those with transient-intraprocedural or post-procedural CHB/HAVB [99 (interquartile range, IQR 97–100)% vs. 72 (IQR 30–99)%, P = 0.02]. Complete recovery (VPP < 1%) was observed in only one patient (2%) with CHB/HAVB. After hospital discharge, no symptomatic bradyarrhythmias or sudden death occurred within 30 days. Patients with pre-existing RBBB exhibited a higher risk of PPMI at 4-year follow-up (26% vs. 8% in non-RBBB patients, P < 0.001).

Conclusion

In patients with pre-existing RBBB, the vast majority of advanced CDs occurred within the 3 days following TAVR, and most did not recover at 1-month, particularly those with intra-procedural persistent CHB/HAVB. These results should help to determine the hospitalization length and timing of PPMI in RBBB patients undergoing TAVR.

Identifying Cardiac Amyloid in Aortic Stenosis: ECV Quantification by CT in TAVR Patients

Objectives

The purpose of this study was to validate computed tomography measured ECV (ECV_CT) as part of routine evaluation for the detection of cardiac amyloid in patients with aortic stenosis (AS)-amyloid.

Background

AS-amyloid affects 1 in 7 elderly patients referred for transcatheter aortic valve replacement (TAVR). Bone scintigraphy with exclusion of a plasma cell dyscrasia can diagnose transthyretin-related cardiac amyloid noninvasively, for which novel treatments are emerging. Amyloid interstitial expansion increases the myocardial extracellular volume (ECV).

Methods

Patients with severe AS underwent bone scintigraphy (Perugini grade 0, negative; Perugini grades 1 to 3, increasingly positive) and routine TAVR evaluation CT imaging with ECV_CT using 3- and 5-min post-contrast acquisitions. Twenty non-AS control patients also had ECV_CT performed using the 5-min post-contrast acquisition.

Results

A total of 109 patients (43% male; mean age 86 ± 5 years) with severe AS and 20 control subjects were recruited. Sixteen (15%) had AS-amyloid on bone scintigraphy (grade 1, n = 5; grade 2, n = 11). ECV_CT was 32 ± 3%, 34 ± 4%, and 43 ± 6% in Perugini grades 0, 1, and 2, respectively (p < 0.001 for trend) with control subjects lower than lone AS (28 ± 2%; p < 0.001). ECV_CT accuracy for AS-amyloid detection versus lone AS was 0.87 (0.95 for ^99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid Perugini grade 2 only), outperforming conventional electrocardiogram and echocardiography parameters. One composite parameter, the voltage/mass ratio, had utility (similar AUC of 0.87 for any cardiac amyloid detection), although in one-third of patients, this could not be calculated due to bundle branch block or ventricular paced rhythm.

Conclusions

ECV_CT during routine CT TAVR evaluation can reliably detect AS-amyloid, and the measured ECV_CT tracks the degree of infiltration. Another measure of interstitial expansion, the voltage/mass ratio, also performed well.

Clinical Impact of Preexisting Right Bundle Branch Block after Transcatheter Aortic Valve Replacement: A Systematic Review and Meta-Analysis

Introduction

Transcatheter aortic valve replacement (TAVR) is now the treatment of choice for patients with severe aortic stenosis regardless of their surgical risk. Right bundle branch block (RBBB) can be a predictor for development of significant atrioventricular (AV) block after TAVR, requiring permanent pacemaker implantation (PPI). However, data related to the risk of PPI requirement with preexisting RBBB is scarce. Hence, this systematic review and meta-analysis aims to assess clinical outcomes of patients undergoing TAVR with RBBB on preexisting electrocardiogram.

Methods

We performed a systematic literature review to identify randomized and nonrandomized clinical studies that reported any clinical impact of patients undergoing TAVR with preexisting RBBB. A total of eight databases including PubMed (Medline), Embase, Cochrane Library, ACP Journal Club, Scopus, DARE, and Ovid containing articles from January 2000 to May 2020 were analyzed.

Results

We identified and screened 224 potential eligible publications through the databases and found 14 relevant clinical trials for a total of 15,319 participants. There was an increased 30-day pacemaker implantation rate of 38.1% in the RBBB group compared to 11.4% in the no RBBB group with a risk ratio of 3.56 (RR 3.56 (95% CI 3.21–3.93, p < 0.01)). There was an increased 30-day all-cause mortality in the RBBB group of 9.5% compared with 6.3% in the no RBBB group with an odds ratio of 1.60 (OR 1.60 (95% CI 1.14–2.25, p < 0.01)).

Conclusion

This study indicates that patients with preexisting RBBB have higher incidence of PPI and all-cause mortality after TAVR compared with patients without RBBB. Further trials are needed to compare the clinical outcomes based on TAVR valve types and assess the benefit of PPI in patients with new-onset RBBB after TAVR.

Use of Electrophysiological Studies in Transcatheter Aortic Valve Implantation

New conduction disturbances requiring permanent pacemaker implantation remain common complications following transcatheter aortic valve implantation (TAVI). It has been suggested that electrophysiological studies could help identify patients who will require permanent pacemaker implantation after TAVI. This article summarises contemporary data on the use of electrophysiological studies in patients undergoing TAVI.

Long-Term Electrocardiographic Changes and Clinical Outcomes of Transcatheter Aortic Valve Implantation Recipients Without New Postprocedural Conduction Disturbances

The objective of this study was to determine the long-term (>1 year) electrocardiographic (ECG) and clinical outcomes of patients without significant changes in their electrocardiogram after transcatheter aortic valve implantation (TAVI; including patients with pre-existing ECG abnormalities). Among 772 consecutive patients who underwent TAVI in our institution, 397 patients (51%) without new ECG changes were included. TAVI patients were divided into 2 groups according to the presence of pre-existing ECG-conduction disturbances (ECG-CD: 140 patients, non-ECG-CD: 257 patients). Clinical follow-up (median: 35 [22 to 57] months) was complete in all patients but 5 (1.2%), and ECG data were available in 291 patients (84.3% of patients at risk) at a median of 29 (20 to 50) months. In the non-ECG-CD group, most patients (79.8%) remained without significant ECG changes at follow-up, and 16.9% developed first-degree atrioventricular block and/or bundle branch block over time. The rate of permanent pacemaker (PPM) implantation at follow-up was 3.5% (1.1%/year) in the non-ECG-CD group versus 15.7% (5.5%/year) in the ECG-CD group (p <0.001). The presence of pre-existing CD was an independent predictor of PPM at follow-up (hazard ratio [HR] 4.67, 95% confidence interval [CI] 2.15 to 10.16, p <0.001). The ECG-CD group exhibited a higher risk of heart failure hospitalization (non-ECG-CD: 25%, ECG-CD: 29%, log-rank p = 0.01), but not mortality (non-ECG-CD: 50%, ECG-CD: 46%, log-rank p = 0.60) at 5-year follow-up. In conclusion, the ECG remained unchanged in most TAVI recipients without new postprocedural CD. Pre-existing ECG-CD was associated with an increased risk of PPM and heart failure hospitalization at long-term follow-up. These results provide reassuring data in the era of TAVI expanding toward candidates with a longer life expectancy, and highlight the importance of a closer follow-up of those patients with pre-existing ECG-CDs.

Utility of 30-Day Continuous Ambulatory Monitoring to Identify Patients With Delayed Occurrence of Atrioventricular Block After Transcatheter Aortic Valve Replacement

Background:

Mechanical injury in the conduction system requiring permanent pacemaker (PPM) associated with transcatheter aortic valve replacement (TAVR) procedure is a common complication. The objective of this study was to use ambulatory monitor BodyGuardian to assess late occurrence of atrioventricular block (AVB) after TAVR.

Methods:

This prospective study evaluated 365 patients who underwent TAVR at Mayo Clinic, Rochester, Minnesota between June 2016 and August 2017. Patients who received PPM for bradycardia after TAVR before discharge were considered as the PPM group. Those not requiring PPM received a BodyGuardian system (BodyGuardian group) for 30 days of continuous monitoring. Primary end point was Mobitz II or third-degree atrioventricular block (II/III AVB) at 30-day follow-up.

Results:

Of 365 patients, 74 who had a PPM or an implantable cardioverter-defibrillator before TAVR and 94 who were enrolled in other studies were excluded. Of 197 patients enrolled in the study, 70 (35.5%) received PPM and 127 had BodyGuardian before the hospital dismissal. Eleven of 127 (8.6%) BodyGuardian group required PPM within 30 days after TAVR for late occurrence of symptomatic bradycardia. In total, 33 of 197 (16.7%) patients developed II/III AVB (24 before and 9 after discharge). Thirty-four patients had preexisting right bundle branch block. Of them, 16 (47%) developed II/III AVB. Of 53 patients who developed new left bundle branch block after TAVR, 14% progressed to II/III AVB within 30 days.

Conclusions:

In patients without a standard post-TAVR pacing indication, yet a potential risk to develop AVB, a strategy of 30-day monitoring identifies additional patients who require permanent pacing.

Transcatheter Aortic Valve Replacement: Procedure and Outcomes

Initially, transcatheter aortic valve replacement (TAVR) was only used in patients with severe symptomatic aortic stenosis and prohibitive risk for surgical aortic valve replacement. Subsequently, TAVR was extended to patients with high and intermediate surgical risk. Recently, the results of randomized trials in low-surgical-risk patients showed superiority or noninferiority of TAVR versus surgical aortic valve replacement in this population. Procedural outcomes have been improved. Long-term durability of transcatheter heart valves remains to be confirmed. This article presents the evolution and current status of TAVR, with respect to the different types of devices and procedures as well as its outcomes.

Pacemaker Implantation and Dependency After Transcatheter Aortic Valve Replacement in the REPRISE III Trial

Background

As transcatheter aortic valve replacement expands to younger and/or lower risk patients, the long‐term consequences of permanent pacemaker implantation are a concern. Pacemaker dependency and impact have not been methodically assessed in transcatheter aortic valve replacement trials. We report the incidence and predictors of pacemaker implantation and pacemaker dependency after transcatheter aortic valve replacement with the Lotus valve.

Methods and Results

A total of 912 patients with high/extreme surgical risk and symptomatic aortic stenosis were randomized 2:1 (Lotus:CoreValve) in REPRISE III (The Repositionable Percutaneous Replacement of Stenotic Aortic Valve through Implantation of Lotus Valve System—Randomized Clinical Evaluation) trial. Systematic assessment of pacemaker dependency was pre‐specified in the trial design. Pacemaker implantation within 30 days was more frequent with Lotus than CoreValve. By multivariable analysis, predictors of pacemaker implantation included baseline right bundle branch block and depth of implantation; diabetes mellitus was also a predictor with Lotus. No association between new pacemaker implantation and clinical outcomes was found. Pacemaker dependency was dynamic (30 days: 43%; 1 year: 50%) and not consistent for individual patients over time. Predictors of pacemaker dependency at 30 days included baseline right bundle branch block, female sex, and depth of implantation. No differences in mortality or stroke were found between patients who were pacemaker dependent or not at 30 days. Rehospitalization was higher in patients who were not pacemaker dependent versus patients without a pacemaker or those who were dependent.

Conclusions

Pacemaker implantation was not associated with adverse clinical outcomes. Most patients with a new pacemaker at 30 days were not dependent at 1 year. Mortality and stroke were similar between patients with or without pacemaker dependency and patients without a pacemaker.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov/. Unique identifier NCT02202434.

Common Postcardiothoracic Surgery Arrhythmias

Cardiac arrhythmias are common after cardiac surgery and have profound sequelae. Bradycardias are typically transient and have reversible causes; however, persistent atrioventricular block is an indicator for permanent pacemaker implantation after valvular surgery. Transcatheter aortic valve surgery is associated with even higher rates of permanent pacemaker implantation. Atrial fibrillation, the most common postoperative arrhythmia, is associated with ischemic stroke, myocardial infarction, congestive heart failure, and short-term mortality. Ventricular arrhythmias have extremely high in-hospital mortality, as well as long-term mortality for those who survive the initial event. Implantable cardioverter-defibrillators have been shown to reduce long-term mortality for these patients.

The Association between Transcatheter Aortic Valve Replacement (TAVR) Approach and New-Onset Bundle Branch Blocks

INTRODUCTION

Transcatheter aortic valve replacement (TAVR) has become a widely accepted treatment option for patients with severe aortic stenosis (AS) who are considered intermediate- and high-risk surgical candidates. The purpose of this study was to test the hypothesis that trans-apical TAVR would be associated with increased risk of new-onset intraventricular conduction delay (LBBB or RBBB).

METHODS

We conducted a retrospective observational study of consecutive patients undergoing TAVR at a large, single institution. The incidence of new LBBB or RBBB was compared between femoral and apical TAVR patients. Multivariate analysis was performed to account for confounding variables, which included age, gender, CAD, PAD, hypertension, and diabetes.

RESULTS

A total of 467 TAVR patients were included in the study, with 283 (60.6%) femoral approach and 184 (39.4%) apical approach. In univariate analysis, the apical approach (when compared to the femoral approach) was associated with a higher incidence of both new-onset LBBB (12.79 vs. 3.40%, p = 0.0002) and RBBB (5.49 vs. 0.81%, p = 0.0039). After controlling for potential confounding variables, the apical approach continued to be associated with a higher incidence of both new-onset LBBB (p = 0.0010) and RBBB (p = 0.0115). There was also a trend towards an association between diabetes and new-onset LBBB (p = 0.0513) in apical TAVR patients. In subgroup analysis, LBBB/RBBB occurring as a result of transapical TAVR was associated with more frequent hospitalizations > 30 days after TAVR, compared to transfemoral TAVR. Other post-procedural complications noted more frequently among patients undergoing transapical TAVR include arrhythmias including atrial fibrillation, peri-procedural myocardial infarction (within 72 h), mortality from unknown cause, and mortality from non-cardiac cause.

CONCLUSIONS

Relative to transfemoral TAVR, patients undergoing transapical TAVR are at increased risk for new-onset bundle branch block, peri-procedural myocardial infarction, rehospitalization, TAV-in-TAV deployment, and all-cause mortality at 1 year. Interventional cardiologists and cardiothoracic surgeons alike should take these findings into consideration when choosing which approach is most suitable for patients undergoing TAVR for severe aortic stenosis.

Pacemaker implantation after transcatheter aortic valve: why is this still happening?

During the past years, the industry and most transcatheter aortic valve operators have focused on reduction of paravalvular leaks rather than on the reduction of permanent pacemakers (PPM). However, since indication for transcatheter aortic valve implantation (TAVI) is moving toward a healthier and younger patient population, new PPMs may become more of an issue. Certain factors such as pre-existing conduction disorders or anatomical features cannot be changed. However, the amount of mechanical trauma to the conduction system and periprocedural medical management offers the potential for optimization. By optimizing our procedure, we may finally be able to achieve low, surgical-like, PPM rates.

Delayed pacemaker requirement after transcatheter aortic valve implantation with a new-generation balloon expandable valve: Should we monitor longer?

OBJECTIVES

To analyze the timing of appearance of conduction abnormalities (CAs) after transcatheter aortic valve implantation (TAVI), to identify predictors of delayed CAs requiring pacemaker (PM) implantation and to provide guidance regarding the duration of telemetry monitoring.

BACKGROUND

How long patients remain at risk of development of CAs requiring PM implantation after TAVI and for how long they should be monitored remains unclear but is crucial when considering early discharge.

METHODS

Development of CAs was studied in 701 consecutive patients treated with Edwards Sapien 3 valves and monitored with telemetry for 7 days in a single center. After excluding valve-in-valve procedures and patients with previous PM, 606 patients remained for analysis. Predictors of CAs requiring PM and the time of onset of CAs were analyzed.

RESULTS

Of 606 patients 76 (12.5%) required a PM after TAVI. CAs requiring PM implantation occurred after 48 h in 22.4% (17 patients) and in 10.5% (8 patients) even after 5 days. Of the patients who developed high grade CAs requiring PM after 48 h, 47.1% had no CAs prior to TAVI, and 23.5% had neither pre-existing CAs nor new-developed CAs within the first 48 h after TAVI.

CONCLUSION

After TAVI using a new-generation balloon-expandable valve, delayed development of CAs requiring PM implantation is not uncommon, even after 5 days. More importantly, 23.5% of patients eventually requiring a delayed PM implantation had still no CAs at 48 h after TAVI in this study. These results question the safety of early discharge and support ECG monitoring for a longer time period. The most optimal way to monitor these patients is yet to be determined.

Permanent pacemaker insertion in patients with conduction abnormalities post transcatheter aortic valve replacement: a review and proposed guidelines

Conduction abnormalities are a common and serious complication of transcatheter aortic valve replacement (TAVR) with well-established predictive factors. Current guidelines are not concrete, leaving several questions unanswered about indications, timing and risks of pacemaker implantation post-TAVR. In this review article, we discuss current guidelines, predictors of pacemaker implantation, clinical implications of this procedure and our recommendations for reducing the pacemaker implantation rate post-TAVR.