The Association Between Right Bundle Branch Block and Long-term Mortality Post-TAVI – Data from the UK TAVI Registry

Leeds Teaching Hospitals NHS Trust (LTH) requires access to NHS England data for the purpose of the following service evaluation:

The Association Between Right Bundle Branch Block and Long-term Mortality Post- Transcatheter Aortic Valve Implantation (TAVI)

The following is a summary of the aims of the service evaluation provided by LTH:

Previously published data have demonstrated an association between right bundle branch block (RBBB) and long-term mortality following TAVI. Mortality was increased up to 2 years post-TAVI in patients with RBBB at discharge but was confined to those patients without a permanent pacemaker (PPM). Those patients with RBBB AND a PPM had long-term mortality equivalent to patients without RBBB, strongly suggesting that increased mortality in RBBB patients is likely to be due to development of high-grade atrio-ventricular heart block. However, despite this evidence, the 2021 European Society of Cardiology (ESC) guidelines for cardiac pacing gave a level 3 indication (i.e. not recommended) for ‘prophylactic’ PPM for patients with baseline RBBB undergoing TAVI.

The discrepancy between published data demonstrating increased risk of late cardiovascular mortality for patients with RBBB and no PPM following TAVI, and international guidelines which strongly discourage prophylactic PPM for this group of patients, has resulted in confusion as to the best approach to treat these patients, with varying practice across centres.

The aim of this evaluation is to use data from the UK TAVI Registry to undertake the largest and longest-term analysis yet conducted into the association between right bundle branch block (RBBB) and long-term mortality post-TAVI, in order to determine whether RBBB is associated with increased mortality, and whether any impact on mortality is influenced by the presence or absence of a permanent pacemaker.

Patients who have undergone TAVI in the UK will be separated into those with baseline RBBB and those without, and a comparison made with respect to all-cause mortality using linked ONS data. Further stratification will be made into those with no RBBB and no permanent pacemaker (PPM), no RBBB but with a PPM, RBBB and no PPM, and RBBB with a PPM and comparison of all-cause risk-adjusted mortality made across these groups. Survival rates will be summarised, and groups will then be compared.

The following NHS England Data will be accessed:

> Transcatheter Aortic Valve Implantation (TAVI)

> Civil Registration Mortality

These datasets are necessary to assess the association between RBBB and mortality following TAVI, and whether or not prophylactic implantation of a PPM can alter this.

The level of the Data will be:

> Pseudonymised

The Data will be minimised as follows:

> Limited to a study cohort of patients who have undergone TAVI in England and Wales between 01/01/2007 and 31/03/2023 within the TAVI registry. It is estimated that 43,032 individuals will be identified.

LTH is the controller as the organisation responsible for ensuring that the Data will only be processed for the purpose described above.

The lawful basis for processing personal data under the UK GDPR is:

Article 6(1)(e) - processing is necessary for the performance of a task carried out in the public interest or in the exercise of official authority vested in the controller;

The lawful basis for processing special category data under the UK GDPR is:

Article 9(2)(j) - processing is necessary for archiving purposes in the public interest, scientific or historical research purposes or statistical purposes in accordance with Article 89(1) based on Union or Member State law which shall be proportionate to the aim pursued, respect the essence of the right to data protection and provide for suitable and specific measures to safeguard the fundamental rights and the interests of the data subject.

The volume of TAVI procedures carried out in the UK is increasing annually, and is forecast to continue rising. In 2022/23, 7697 TAVI procedures were carried out. Identifying factors which increase procedure-related mortality, as well as interventions which could potentially mitigate these, will be of public interest.

The funding is provided by the British Cardiovascular Intervention Society (BCIS). The funding is specifically for the study described.

The funder will have no ability to suppress or otherwise limit the publication of findings.

This project was reviewed and supported by the NICOR Research Access Committee (RAC) on 06/06/2024.

No data will flow to NHS England for the purposes of this Data Sharing Agreement (DSA).

NHS England will provide the relevant records from the TAVI and mortality datasets to LTH. The Data will contain no direct identifying data items. The Data will be pseudonymised and individuals cannot be reidentified. The Data will not be linked with any other data.

The Data will be stored on servers at LTH.

The Data will be accessed onsite at the premises of LTH only.

The Data will not leave England at any time.

Access is restricted to employees or agents of LTH who have authorisation from the Principal Investigator.

All personnel accessing the Data have been appropriately trained in data protection and confidentiality.

Analysts from LTH will analyse the Data for the purposes described above.

The expected outputs of the processing will be:

> A manuscript to be published in a peer-reviewed medical journal

> Results will be presented at appropriate national and international medical conferences

The outputs will not contain NHS England Data and will only contain aggregated information with small numbers suppressed as appropriate in line with the relevant disclosure rules for the dataset(s) from which the information was derived.

The outputs will be communicated to relevant recipients through the following dissemination channels:

> Journals

> Conferences

> Headline results from publications may also be shared via social media

LTH will aim to present the results at conferences in late 2025 and publish the manuscript in early 2026.

The BCIS will assist in disseminating the findings to its members to advertise the findings to a wider audience.

The results from this analysis are expected to inform decision making regarding the necessity of prophylactic PPM implantation prior to TAVI in patients with pre-existing RBBB. The result could potentially have an impact on patient care and health economics. The results are likely to influence national and international guidelines. Whether the results support implantation, or suggest that it is not necessary, there will be a significant impact upon health and social care in terms of expenditure and resource allocation.

The use of the data could:

> help the system to better understand the health and care needs of populations.

> lead to the identification or improvement of treatments or interventions, or health and care system design to improve health and care outcomes or experience.

> inform planning health services and programmes, for example to improve equity of access, experience and outcomes.

> inform decisions on how to effectively allocate and evaluate funding according to health needs.

> provide a mechanism for checking the quality of care. This could include identifying areas of good practice to learn from, or areas of poorer practice which need to be addressed.

> support knowledge creation or exploratory research (and the innovations and developments that might result from that exploratory work).

The findings are expected to allow LTH to more accurately risk-stratify patients undergoing TAVI, potentially reducing procedure-related mortality. The findings are also expected to inform the medical community about whether prophylactic implantation of a PPM in patients with RBBB is beneficial or not, which may allow mitigation of mortality risk is selected patients.

The proposed outputs are expected to quantify the increased mortality risk associated with RBBB in the context of TAVI, and what mitigation (if any) prophylactic implantation of a PPM provides.

Yielded Benefits is not a requirement for new applications.