Despite advancements in implantation techniques, high-grade AVB continues to occur in 6-15% of patients following TAVI, with most cases presenting within the first 24 hours post procedure. However, a significant proportion of patients develop this conduction disorder later, beyond the initial 24 hours. Due to this risk, hospital stays after TAVI are often extended beyond one day, and only 12% of patients are discharged the day after the procedure.

In this context, this study aims to identify predictors of high-grade AVB after TAVI and to develop a risk stratification tool to identify low-risk patients who may be safely discharged within 24 hours post procedure.

To achieve this, a retrospective observational study was conducted, including patients who underwent TAVI between March 2014 and June 2023, with the objective of analyzing the incidence of high-grade AVB. To validate the model, a second combined retrospective and prospective cohort was used. Clinical, procedural, and electrocardiographic parameters were analyzed to identify independent predictors of AVB and to develop a risk score.

A total of 1,290 patients were included in the analysis of group A (derivation cohort), of whom 5.7% (n = 74) developed high-grade AVB at a median of 3 days. No statistically significant differences in comorbidities were found between patients with and without AVB. Subsequently, the parameters identified in group A were validated in group B (validation cohort, n = 936). Patients with a prior pacemaker and those who developed high-grade AVB within the first 24 hours were excluded from the study.

Using multivariate logistic regression analysis, the following independent predictors of late AVB were identified for the development of a risk scoring system:

• Implantation of self-expanding prosthetic valves
• Greater implantation depth
• Presence of prolonged PR interval before the procedure
• Increase in PR interval at 24 hours post implantation
• Presence of preprocedural right bundle branch block (RBBB)
• Development of new-onset left bundle branch block (LBBB) and RBBB at 24 hours post implantation

Based on these parameters, the D-PACE (Delayed atrioventricular block Prediction for eArly disChargE) score was developed to stratify the risk of late AVB into three subgroups:

• Low risk (0-3 points)
• Intermediate risk (4-5 points)
• High risk (≥6 points)

According to these criteria, low-risk patients had an incidence of late AVB below 1%, representing 48.6% and 33.3% of the derivation and validation cohorts, respectively.

Based on these findings, the authors conclude that the D-PACE score is a useful tool for identifying patients at low risk for late AVB, allowing the implementation of safe early discharge strategies within 24 hours post-TAVI.

COMMENTARY:

In recent years, the number of TAVI procedures has increased exponentially, resulting in a higher healthcare burden. Therefore, it is essential to identify parameters that enable safe and efficient early discharge.

Previous studies have demonstrated that next-day discharge after TAVI is feasible and safe. However, these studies have included cohorts with a low incidence of advanced AVB, which limits their applicability in clinical practice. In this context, the D-PACE score emerges as a tool designed to identify patients at low risk for advanced AVB, thereby facilitating safe early discharge.

The D-PACE score has demonstrated high predictive accuracy for stratifying the risk of late AVB following TAVI, with an AUC of 0.879 in the derivation cohort and 0.799 in the validation cohort, reinforcing its external validity.

This study presents several points of interest. One of the most relevant findings is that patients receiving self-expanding valves had a higher incidence of AVB, while none of the patients undergoing a valve-in-valve procedure due to degeneration of a surgical prosthesis developed this complication. This protective effect may be attributed to the presence of a rigid ring in the surgical valve, which minimizes the impact on the cardiac conduction system.

Moreover, while LBBB had already been identified as a risk factor for the need for pacemaker implantation, this study is the first to indicate that new-onset RBBB is also an independent risk factor.

Additionally, the study did not report cases of sudden death or resuscitation, supporting the low probability of critical AVB after early discharge.

Despite its contributions, this study has certain limitations. First, some independent predictors identified in previous studies, such as the volume and distribution of calcium in the aortic valve and the left ventricular outflow tract, as well as membranous septum length measured by computed tomography, were not included. The use of atrial pacing stimulation to determine the Wenckebach point, a parameter with negative predictive value for AVB, was also not evaluated.

Another important limitation is the restricted applicability of the score. The D-PACE score is only applicable to patients in sinus rhythm, as one of its key parameters is the PR interval, preventing its use in patients with atrial fibrillation. Although the authors proposed an alternative version, the D-PACE AF score, it still requires further validation before being implemented in clinical practice.

Another aspect to consider is that, given that most patients were treated with Evolut® (Medtronic®) or SAPIEN® (Edwards Lifesciences) prostheses, the study results may not be generalizable to other prostheses, as they were underrepresented in this analysis.

Finally, in addition to AV conduction disturbances, TAVI can lead to other clinical complications that delay discharge, factors that were not addressed in this study.

In conclusion, this study introduces a novel and clinically useful scoring system for predicting late AVB after TAVI, facilitating early discharge in low-risk patients. However, additional prospective studies are needed to validate its applicability.

REFERENCE:

Bendandi F, Taglieri N, Ciurlanti L, Mazzapicchi A, Foroni M, Lombardi L, et al. Development and validation of the D-PACE scoring system to predict delayed high-grade conduction disturbances after transcatheter aortic valve implantation. EuroIntervention. 2025 Jan 20;21(2):e119-e129. doi: 10.4244/EIJ-D-24-00850.