Study on Heart Block Risks Using Outcome-Based Modeling (SAVIOR)

Sun Yat-sen University

Status: Completed

Conditions: Left Bundle-Branch Block; Aortic Stenosis

Treatments: Other: The population undergoing TAVR for aortic valve stenosis with outcomes of permanent pacemaker implantation and complete left bundle branch block after surgery

Study type: Observational

Funder types: Other

Identifiers

NCT07065123

AS-TAVR-2023-04-10

Details and patient eligibility

About

This study developed a prediction model for high-grade atrioventricular block (AVB) and complete left bundle branch block (CLBBB) following transcatheter aortic valve replacement (TAVR) in Chinese patients with aortic stenosis (AS). Analyzing 112 patients from Sun Yat-sen Memorial Hospital (2017-2024), the study incorporated clinical, electrocardiographic, and procedural variables to identify risk factors via logistic regression. A nomogram was constructed and validated internally (bootstrapping) and externally (temporal validation), with performance assessed using AUC, C-index, and calibration tests. The model aims to improve preoperative risk stratification and guide individualized management for TAVR-related conduction disturbances in this understudied population. Analyses were conducted in R 4.2.3 (significance: *p* < 0.05).

Full description

In recent years, transcatheter aortic valve replacement (TAVR) has emerged as a minimally invasive surgical approach and has gradually become a standard treatment option for patients with moderate to severe aortic stenosis（AS), particularly those at high surgical risk or deemed ineligible for conventional surgery. TAVR has been widely adopted in clinical practice.

However, post-TAVR cardiac conduction disturbances are among the most frequently observed complications, particularly complete left bundle branch block (CLBBB) and high-degree atrioventricular block (AVB) requiring permanent pacemaker implantation (PPI). These complications are associated with an increased risk of heart failure and cardiac mortality. Identified risk factors include patient-specific characteristics, electrocardiographic features, intraoperative procedural techniques, and the type of device used.

Current research on post-TAVR conduction disorders predominantly focuses on Western populations. However, Chinese AS patients exhibit distinct clinical features-such as higher degrees of valve calcification and a higher prevalence of bicuspid aortic valves-which may lead to differences in risk factors for conduction abnormalities. Moreover, prior studies have largely focused on isolated risk factors rather than developing integrated models to quantify the risk of such complications. Against this backdrop, the purpose of this study is to address the knowledge gap in postoperative risk prediction for Chinese patients. By constructing a risk prediction model tailored to Chinese AS patients for post-TAVR cardiac conduction block, we aim to improve preoperative risk assessment and individualized clinical management, thereby providing actionable guidance for clinical decision-making.

This study included 112 aortic stenosis patients undergoing TAVR at Sun Yat-sen Memorial Hospital (2017-2024), divided into internal (2017-2022) and external (2023-2024) validation cohorts.

Data covered demographics, medical history, ECG, echocardiography, biomarkers, and valve parameters. Outcomes were permanent pacemaker implantation (PPI) ≤48h post-TAVR and complete left bundle branch block (CLBBB).

Univariate logistic regression (p<0.20 threshold) and stepwise multivariate analysis (R "MASS" package, AIC-based) identified predictors for nomogram development. Model performance was assessed via AUC, C-index, ROC, and Hosmer-Lemeshow test. Internal validation used 1000 bootstrap resamples; external validation employed temporal validation. Analyses were performed in R 4.2.3 (significance: p<0.05).

Enrollment: 112 patients

Sex: All

Volunteers: No Healthy Volunteers

Inclusion criteria

• Adult patients (≥18 years old) with severe symptomatic aortic stenosis (AS) meeting 2021 ESC/EACTS Guidelines and Chinese Expert Consensus criteria (AVA <1.0 cm², or peak jet velocity ≥4.0 m/s, or mean gradient ≥40 mmHg)
• Scheduled to undergo transcatheter aortic valve replacement (TAVR) in Sun Yat-Sen Memorial Hospital

Exclusion criteria

• Pre-existing complete left bundle branch block (CLBBB) on baseline ECG
• Patients with pre-existing permanent pacemaker implantation
• Inability to comply with follow-up protocol

Trial design

112 participants in 2 patient groups

Permanent pacemaker implantation after TAVR surgery

Treatment:

Other: The population undergoing TAVR for aortic valve stenosis with outcomes of permanent pacemaker implantation and complete left bundle branch block after surgery

Complete left bundle branch block occurred after TAVR surgery

Treatment:

Other: The population undergoing TAVR for aortic valve stenosis with outcomes of permanent pacemaker implantation and complete left bundle branch block after surgery