- Academic Editors
†These authors contributed equally.
Background: Transcatheter aortic valve replacement (TAVR) is an
effective alternative treatment for patients with aortic stenosis (AS) who have
intermediate to high surgical risk or who are inoperable. However, the incidence
of conduction abnormalities is high after TAVR, which can reduce the
effectiveness of the surgery. Our research objective is to explore the risk
factors of new-onset conduction abnormalities after TAVR, providing reference
value for clinical doctors to better prevent and treat conduction abnormalities.
Methods: Patients who underwent TAVR were divided into those who
developed heart block and those who did not. Baseline clinical characteristics,
cardiac structural parameters, procedural characteristics, electrocardiogram (ECG) changes before and
after TAVR (
Aortic stenosis (AS) is one of the common cardiac valvular diseases in elderly patients. It is characterized by progressive valve stenosis. Due to the aging of the population, the prevalence rate is expected to double in the next 20 years. The survival period of patients with severe AS is greatly shortened and the mortality rate is very high [1, 2, 3]. Therefore, it is necessary to replace the aortic valve in time. However, most elderly patients are weak, have poor tolerance to surgical aortic valve replacement, and have high surgical risk. Minimally invasive transcatheter aortic valve replacement (TAVR) has become a viable alternative in such patients [3, 4, 5]. TAVR can improve the clinical outcome of these patients, but the related clinical complications are relatively serious and complex. Conduction abnormalities are among the common complications of TAVR, which may tend to limit the promotion of this surgery to younger, lower-surgical-risk, populations [6]. Left bundle branch block (LBBB) is the most common type of heart block after TAVR, and its incidence in the first-generation valves is 4–65% [7, 8, 9, 10]. Of the different types of conduction abnormalities, high-grade atrioventricular block (HAVB) is among the more serious, with an incidence of 10–25% [11]. Most of those patients need to receive an implanted permanent pacemaker (PPM). In recent years, the precision of surgical instruments has been improved and data from surgeries have accumulated, but the incidence of conduction abnormalities has not decreased [12, 13, 14]. Conduction abnormalities may lead to further deterioration of cardiac function in patients with AS, increase the risk of heart failure (HF) and death, and adversely affect prognosis. Accordingly, predicting, preventing, and treating heart block has become the next frontier for improving TAVR outcomes. The present study analyzed the risk factors of new-onset heart block after TAVR in patients with severe AS and HF.
Our study complied with the Declaration of Helsinki ethics statement. The study
received approval from the institutional scientific review board. All patients
provided written informed consent. The study sample included patients who
underwent TAVR at the Yantai Yuhuangding Hospital Affiliated to Qingdao
University and the affiliated Second Hospital of Tianjin Medical University, from
January 2017 to September 2022. The inclusion criteria included: (1) underwent
TAVR for symptomatic severe AS (mean gradient
All patients were assessed by the TAVR cardiac team. The indication for TAVR, procedural concerns, surgical access site, as well as transcatheter heart valve type and size, were discussed and determined based on preoperative imaging examinations that included echocardiography, multislice computed tomography (MSCT), and angiography.
All patients received general anesthesia. The main procedures included: (1) selection of the appropriate valve size according to the preoperative examination results; (2) femoral artery approach was the first choice (5 cases of transapical TAVR), temporary pacemaker was placed, pigtail catheter was placed to the base of the non-coronary sinus, and aortic root angiography was performed to assist in positioning; (3) the transmitter was passed to the aortic root, followed by release of the valve under the guidance of rapid pacing and aortic root angiography. Different release strategies were adopted according to different situations with the goal of fitting the stent valve to the valve ring; (4) aortography was performed and the patient was monitored for possible perivalvular leakage or obstruction of the coronary artery orifice.
Baseline characteristics for each participant were collected. These included
demographics (age, sex), New York heart association (NYHA) class, smoking, drinking, medical comorbidities such as hyperlipidemia, diabetes, dyslipidemia, malignant tumor, coronary heart
disease, atrial fibrillation (AF), and previous history of cardiac surgery.
Laboratory analyses included B-type natriuretic peptide (BNP), uric acid, total
glyceride, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C)
and high-density lipoprotein cholesterol, creatinine, and glomerular filtration
rate. All echocardiograms were obtained with the patient in a stable hemodynamic
condition. Echocardiographic parameters included left atrium anteroposterior
diameter, left ventricular end-diastolic dimension, right ventricular
anteroposterior diameter, etc. We also collected procedural characteristics, such
as surgical approach, valve oversize rate, valve type, and valve size. Valve
oversize rate = (valve model/aortic annulus diameter-1)
Data analysis was performed with SPSS (version 25.0, IBM Corp., Armonk, NY,
USA). First, we ran univariate analyses. Categorical variables were expressed as
n (%). Categorical data were compared using the Chi-square test or Fisher’s
exact probability test. The Shapiro-Wilk test is used to analyze the normality of
the continuous data. Normally distributed continuous variables were presented as
mean (standard deviation, SD). Non-normally distributed continuous variables are
presented as median (interquartile range, IQR). Continuous data were compared
using Student’s t-test (normality) or Mann-Whitney U test
(non-normality). Parameters with p
A total of 93 patients were included, of whom 32 developed new-onset heart block after TAVR. Among those 32, 3 presented with first-degree atrioventricular block (2 of these had concurrent LBBB), which occurred within 24 h after TAVR. There were 9 patients who presented with third-degree atrioventricular block, of which 8 occurred within 24 h and 1 occurred within 10 days after TAVR. There were 19 patients who presented with LBBB, of which 16 occurred within 24 h after the operation. Six of those 16 cases (37.5%) recovered during follow-up. Three cases showed a delayed presentation. Right bundle branch block (RBBB) occurred in all 3 cases, of which 2 occurred within 24 h (one of 2 cases [50.0%] recovered during follow-up). One case occurred within 3 days after TAVR. Pacemakers were implanted in 9 patients.
There were no statistical differences in baseline characteristics between the two groups, except for prior malignancy and AF, which were of significantly higher frequency in patients who subsequently developed heart block (malignancy: 18.8% vs. 3.3%, p = 0.032; AF: 34.4% vs. 8.2%, p = 0.001). Patients who developed new-onset heart block were more likely to have higher TC (4.87 [1.15] vs. 4.34 [1.13], p = 0.038) and LDL-C (3.03 [0.78] vs. 2.57 [0.94], p = 0.020) before TAVR. As for the echocardiography parameters, there were no statistically significant differences between the two groups (Table 1).
Variables | Heart block (n = 32) | No heart block (n = 61) | T, Z or |
p | ||
Baseline data | Age (years), Mean (SD) | 75.03 (6.41) | 72.28 (7.62) | 1.743 | 0.085 | |
BMI (kg/m |
23.94 (3.85) | 24.50 (3.20) | 0.747 | 0.457 | ||
Women, n (%) | 17 (53.1%) | 27 (44.3%) | 0.661 | 0.416 | ||
NYHA class, n (%) | 4.232 | 0.221 | ||||
I | 4 (12.5%) | 2 (3.3%) | ||||
II | 2 (6.3%) | 3 (4.9%) | ||||
III | 14 (43.8%) | 37 (60.7%) | ||||
IV | 12 (37.5%) | 19 (31.1%) | ||||
Smoking, n (%) | 5 (15.6%) | 21 (34.4%) | 3.684 | 0.055 | ||
Drinking, n (%) | 3 (9.4%) | 14 (23.0%) | 2.590 | 0.108 | ||
Hypertension, n (%) | 21 (65.6%) | 35 (57.4%) | 0.596 | 0.440 | ||
Diabetes, n (%) | 9 (28.1%) | 17 (27.9%) | 0.001 | 0.979 | ||
Tumor, n (%) | 6 (18.8%) | 2 (3.3%) | 4.574 | 0.032 | ||
CHD, n (%) | 15 (46.9%) | 35 (57.4%) | 0.931 | 0.335 | ||
Prior MI, n (%) | 3 (9.4%) | 7 (11.5%) | 0.000 | 1.000 | ||
AF, n (%) | 11 (34.4%) | 5 (8.2%) | 10.098 | 0.001 | ||
Sinus bradycardia, n (%) | 1 (3.1%) | 7 (11.5%) | 0.951 | 0.329 | ||
First-degree AVB, n (%) | 5 (15.6%) | 15 (24.6%) | 0.999 | 0.317 | ||
LBBB, n (%) | 0 (0.0%) | 5 (8.2%) | 1.395 | 0.238 | ||
RBBB, n (%) | 3 (9.4%) | 3 (4.9%) | 0.150 | 0.699 | ||
Cerebral infarction, n (%) | 5 (15.6%) | 7 (11.5%) | 0.058 | 0.809 | ||
CABG, n (%) | 1 (3.1%) | 0 (0.0%) | 0.344 | |||
PCI, n (%) | 5 (15.6%) | 11 (18.0%) | 0.085 | 0.770 | ||
Laboratory examination | TG (mmol/L), Median (IQR) | 0.93 (0.78, 1.31) | 1.01 (0.77, 1.36) | 0.724 | 0.469 | |
TC (mmol/L), Mean (SD) | 4.87 (1.15) | 4.34 (1.13) | 2.100 | 0.038 | ||
LDL-C (mmol/L), Mean (SD) | 3.03 (0.78) | 2.57 (0.94) | 2.373 | 0.020 | ||
HDL-C (mmol/L), Median (IQR) | 1.24 (0.99, 1.51) | 1.24 (0.96, 1.43) | 0.501 | 0.616 | ||
BNP (pg/mL), Median (IQR) | 939.13 (224.70, 2770.12) | 577.87 (179.10, 1461.01) | 1.059 | 0.290 | ||
Ccr (mL/min), Mean (SD) | 71.63 (26.21) | 72.87 (26.68) | 0.214 | 0.831 | ||
Uric acid (µmol/L), Median (IQR) | 415.00 (271.50, 483.75) | 411.00 (300.00, 515.00) | 0.481 | 0.630 | ||
Echocardiography | AO ascending segment (mm), Median (IQR) | 38.00 (32.00, 41.00) | 34.00(31.90, 39.00) | 1.691 | 0.091 | |
LAAD (mm), Mean (SD) | 44.09 (5.97) | 43.94 (5.51) | 0.125 | 0.901 | ||
LVEDD (mm), Mean (SD) | 49.30 (7.51) | 51.55 (7.34) | 1.391 | 0.168 | ||
RVAD (mm), Median (IQR) | 23.95 (21.83, 26.00) | 23.00 (21.00, 24.35) | 1.463 | 0.143 | ||
LVEF (%), Median (IQR) | 60.00 (52.50, 65.75) | 57.00 (44.00, 64.00) | 1.554 | 0.120 | ||
PASP |
4 (12.5%) | 18 (29.5%) | 3.362 | 0.067 |
Remarks: Values are presented as mean (SD), median (IQR) or n (%). p
values
There was no significant difference between the heart block group and the no heart block group in terms of bicuspid aortic valve, surgical approach, balloon size, pre-dilation and post-dilation, valve oversize rate, valve-in-valve surgery, valve type and size (Table 2).
Variables | Heart block (n = 32) | No heart block (n = 61) | Z or |
p | |
BAV, n (%) | 11 (34.4%) | 18 (29.5%) | 0.232 | 0.630 | |
TAVR access, n (%) | 1.395 | 0.238 | |||
TF-TAVR | 32 (100.0%) | 56 (91.8%) | |||
TA-TAVR | 0 (0.0%) | 5 (8.2%) | |||
Pre-dilated balloon size (mm), Median (IQR) | 22.00 (18.00, 23.00) | 22.00 (20.00, 23.00) | 1.807 | 0.071 | |
Post-dilated balloon size (mm), Median (IQR) | 22.00 (20.00, 25.00) | 22.00 (20.00, 23.75) | 0.257 | 0.797 | |
Pre-dilation, n (%) | 3.504 | 0.326 | |||
0 | 6 (18.8%) | 6 (9.8%) | |||
1 | 26 (81.3%) | 50 (82.0%) | |||
2 | 0 (0.0%) | 4 (6.6%) | |||
3 | 0 (0.0%) | 1 (1.6%) | |||
Post-dilation, n (%) | 3.745 | 0.109 | |||
0 | 22 (68.8%) | 34 (55.7%) | |||
1 | 9 (28.1%) | 27 (44.3%) | |||
2 | 1 (3.1%) | 0 (0.0%) | |||
Valve oversize rate (%), Median (IQR) | 9.40 (3.25, 14.85) | 8.21 (0.44, 15.33) | 0.311 | 0.755 | |
Valve-in-valve surgery, n (%) | 3 (9.4%) | 7 (11.5%) | 0.000 | 1.000 | |
Valve type, n (%) | 4.829 | 0.069 | |||
J-VALVE | 0 (0.0%) | 5 (8.2%) | |||
Vita Flow | 4 (12.5%) | 15 (24.6%) | |||
VENUS A | 28 (87.5%) | 41 (67.2%) | |||
Valve size (mm), Median (IQR) | 26.00 (23.25, 29.00) | 26.00 (23.00, 29.00) | 0.671 | 0.503 |
Remarks: Values are presented as median (IQR) or n (%). BAV, bicuspid aortic valve; TAVR, transcatheter aortic valve replacement; TF-TAVR, transfemoral TAVR;
TA-TAVR, transapical TAVR; IQR, interquartile range; J-VALVE, VENUS A, and Vita Flow are the names of valves.
The median difference between postoperative and preoperative heart rate
(
Variable | Heart block (n = 32) | No heart block (n = 61) | T or Z | p |
HR (BPM), Median (IQR) | 74.50 (65.50, 90.75) | 70.00 (62.00, 80.50) | 1.740 | 0.082 |
PR interval (ms), Median (IQR) | 179.50 (151.75, 199.25) | 181.00 (161.50, 204.75) | 0.304 | 0.761 |
QRS wave (ms), Median (IQR) | 96.50 (91.00, 109.50) | 102.00 (91.50, 115.50) | 1.185 | 0.236 |
QT interval (ms), Mean (SD) | 397.94 (55.85) | 419.37 (49.78) | 1.884 | 0.063 |
QTc interval (ms), Median (IQR) | 451.00 (429.50, 470.25) | 460.00 (428.00, 483.50) | 1.096 | 0.273 |
–9.50 (–20.00, 4.00) | 2.00 (–8.00, 11.00) | 2.815 | 0.005 | |
52.00 (24.25, 71.00) | 2.00 (–6.00, 10.00) | 6.019 | ||
77.50 (53.25, 108.00) | 16.00 (–34.50, 52.00) | 4.117 | ||
70.50 (39.50, 94.75) | 10.00 (–22.00, 48.50) | 4.149 |
Remarks: Values are presented as mean (SD) or median (IQR). p values
Univariate analysis was used to identify significant risk factors of new-onset
heart block after TAVR (Tables 1,2,3). Variables with p-values
Variable | Multifactor Logistic Regression Analysis | |||
OR | 95% CI | p | ||
LDL-C (mmol/L) | 0.714 | 2.042 | (1.072, 3.892) | 0.030 |
0.054 | 1.056 | (1.033, 1.079) |
Remarks: p values
Regarding short-term postoperative complications in the heart block group, there was one case of vascular complications, one case of cardiac perforation, and two cases of moderate perivalvular leakage. In the group without heart block, there was one case of acute kidney injury, three cases of vascular complications, one case of poor wound healing, two cases of moderate perivalvular leakage, and four cases of cerebrovascular diseases. However, there was no significant statistical difference between groups in complication rate.
The main findings of our study are as follows: (a) the prevalence of new-onset
heart block was 34.4%, and permanent pacemaker implantation (PPI) was performed
in 9.7% of the cases; (b) patients who developed new-onset heart block were more
likely to have malignancy and AF, as well as higher levels of TC and LDL-C before
TAVR; (c) multivariate logistic regression showed that high preoperative LDL-C
and
Different complications can occur after TAVR, of which many have been identified
as independent predictors of mortality [16, 17]. New-onset LBBB is one of the
most common complications post-TAVR. At times, transient new-onset LBBB persists
at discharge or by 30 days afterward in approximately 55% of cases, leading to a
PPI in 10–20% of cases, most often for HAVB [8, 18, 19]. Previous studies have
reported that new LBBB was associated with increased risks of late (
Altogether, these results suggest that prevention strategies such as smoking cessation, better control of blood pressure, and LDL-C reduction, can delay the progression of AS and associated conduction abnormalities, possibly by reducing inflammation [39, 40]. The impact of TAVR on the conduction system is dynamic; both the timing and duration of conduction block are uncertain, which adds difficulty to the management of related conduction abnormalities. Pacing is the most effective intervention for the newly emerged conduction block. However, the ideal timing of pacing therapy remains uncertain. The determination of the pacing treatment is usually based on the clinical judgment. It should be noted that conduction abnormalities can show delayed presentations, which may be related to tissue edema and late expansion of the prosthesis. If HAVB occurs after TAVR, a PPM is implanted. For high-risk LBBB patients, ECG monitoring can be extended to at least 2–4 weeks. If necessary, further electrophysiological examination can be performed [9]. After TAVR, if dynamic ECG monitoring is not available, ECG monitoring should be conducted regularly, especially focusing on the change of QRS duration, so as to identify high-risk patients with HAVB.
In the present study, several patients had received 24-h ECG monitoring before TAVR. Some were found to have previously unknown paroxysmal arrhythmia or transient conduction disorder, most of whom were asymptomatic. Thus, many baseline arrhythmic events in TAVR patients go undetected or unrecognized. This may lead to bias whereby the rates of new-onset heart block are overestimated. Due to its potential clinical benefits and relatively low cost, the recommendation is for ECG monitoring for at least 24 h before TAVR. For patients with newly discovered arrhythmia, appropriate therapy should be carried out promptly in accordance with the recommendations of current guidelines. The application of 24-h ECG may provide an opportunity to determine the actual incidence of tachyarrhythmias and bradyarrhythmias attributable to the transcatheter prosthesis and the TAVR procedure, which is substantial for the preoperational evaluation of the newer transcatheter valve systems or new indications of TAVR.
This study has some limitations that should be recognized. First, our study should be interpreted with caution due to relatively small sample size. Moreover, due to the routine joint analysis, there are a few missing surgical data. Second, some patients with severe AS did not have ECG monitoring for at least 24 h before surgery, which led to overestimation of abnormal conduction after TAVR. Finally, most patients for TAVR undergo only 12-lead ECG monitoring after TAVR so we inevitably lose some key information on intermittent conduction abnormalities.
Patients who developed new-onset heart block were more likely to have prior
histories of malignancy and AF, and have higher levels of TC and LDL-C before
TAVR. High preoperative LDL-C levels and higher
The datasets used and analyzed during the current study are available from the corresponding author on reasonable request.
TD, TL and FXR designed the research study. MD, LZW and TLL performed the research. LZW, NZ, LHW and TLL conducted data collection. NZ and GT provided help and advice on technology. TD and LHW provided help and advice on language. ZCX, GT and TNC analyzed the data. MD and LZW wrote the manuscript. FXR and TL conducted writing review. All authors contributed to editorial changes in the manuscript. All authors read and approved the final manuscript. All authors have participated sufficiently in the work and agreed to be accountable for all aspects of the work.
The study was conducted in accordance with the Declaration of Helsinki. This study received ethics approval from Affiliated Yantai Yuhuangding Hospital of Qingdao University Ethics Committee. The ethics approval number is 2022-181. All individuals have signed informed consent.
We thank the patients and study coordinators who participated in this research. We would like to thank all our teachers who have helped us to develop the fundamental and essential academic competence.
This research received no external funding.
The authors declare no conflict of interest.
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