Cerebral Microembolization During Transcatheter Aortic Valve Implantation: Comparing Balloon-expandable and Self-expanding Valves

Official title

Cerebral Microembolization During Transcatheter Aortic Valve Implantation: A Randomized Study Comparing Balloon-expandable and Self-expanding Valves

Overview

This study will compare the amount of cerebral microembolization during transcatheter aortic valve implantation (TAVI) between two commonly used types of transcatheter aortic valves: balloon-expandable valves and self-expanding valves. Cerebral microembolization refers to small particles or material that may travel to the brain during the procedure. These signals can be detected using transcranial Doppler ultrasound, a non-invasive method for monitoring blood flow in the brain. Although clinically apparent stroke after TAVI is relatively uncommon, small silent brain lesions may occur, and their mechanisms are not fully understood. Adult patients with severe symptomatic aortic valve stenosis who are scheduled for TAVI will be included. Participants will be randomly assigned to receive either a balloon-expandable or a self-expanding valve, both of which are established and routinely used treatment options. Transcranial Doppler monitoring will be performed before, during, and after the procedure to record the number of microembolic signals. The study will also record neurological events and procedural characteristics, such as procedure duration and the need for balloon dilatation. The aim of the study is to determine whether the type of valve is associated with a different burden of cerebral microembolization during TAVI. The results may help improve understanding of procedural factors related to cerebral embolization and may support future strategies for reducing neurological risk in patients undergoing TAVI.

Detailed description

This is a prospective, randomized, parallel-group clinical study designed to compare cerebral microembolization during transcatheter aortic valve implantation between balloon-expandable and self-expanding transcatheter aortic valves.

The study will be conducted at University Hospital Dubrava and Sisters of Charity Hospital (Zagreb) with an expected duration of one year. Adult patients aged 18 years or older with severe symptomatic aortic valve stenosis and an indication for transcatheter aortic valve implantation will be considered for participation.

Eligible participants will be randomized using a computer-generated randomization sequence into one of two study groups according to the type of implanted valve: a balloon-expandable valve or a self-expanding valve. Both valve types represent standard, widely accepted therapeutic options in contemporary clinical practice. The study does not introduce a new or insufficiently tested technology, and participation will not change the standard course of treatment or expose patients to additional risk beyond that normally associated with the procedure.

All participants will undergo a standard TAVI procedure with periprocedural anticoagulation according to current clinical guidelines. Cerebral microembolization will be assessed using transcranial Doppler ultrasound. Monitoring will be performed immediately before the procedure, during the procedure, and after the procedure. The presence and number of microembolic signals will be recorded, including analysis across specific procedural phases such as instrumentation, valvuloplasty, valve implantation, and the post-implantation period.

The primary outcome will be the difference in the change in the number of microembolic signals between the balloon-expandable and self-expanding valve groups. Secondary outcomes will include the change in microembolic signal burden within each group, the distribution of microembolic signals across procedural phases, the occurrence of new microembolic signals after the procedure, the incidence of clinical neurological events, and the association between procedural characteristics and microembolic signal burden.

Collected data will include demographic and clinical characteristics, such as age, sex, and comorbidities, as well as procedural data including procedure duration, vascular access route, need for predilatation or postdilatation, and procedural complications. Data will be analyzed using appropriate statistical methods for between-group and within-group comparisons, depending on data distribution.

Interventions

• Device Balloon-expandable transcatheter aortic valve
  A balloon-expandable transcatheter aortic valve will be implanted during a standard transcatheter aortic valve implantation procedure in participants randomized to this intervention arm. This valve type is an established and routinely used treatment option for severe symptomatic aortic valve stenosis. Cerebral microembolization will be monitored using transcranial Doppler ultrasound before, during, and after the procedure.
• Device Self-expanding transcatheter aortic valve
  A self-expanding transcatheter aortic valve will be implanted during a standard transcatheter aortic valve implantation procedure in participants randomized to this intervention arm. This valve type is an established and routinely used treatment option for severe symptomatic aortic valve stenosis. Cerebral microembolization will be monitored using transcranial Doppler ultrasound before, during, and after the procedure.

Primary outcome measures

• Change in Number of Cerebral Microembolic Signals During TAVI [Time frame: Before, during, and immediately after the TAVI procedure]

Secondary outcome measures (5)

• Number of Cerebral Microembolic Signals Within Each Study Group [Time frame: Before, during, and immediately after the TAVI procedure]
• Distribution of Cerebral Microembolic Signals by Procedural Phase [Time frame: During the TAVI procedure and immediately after valve implantation]
• Occurrence of New Cerebral Microembolic Signals After TAVI [Time frame: Immediately after the TAVI procedure]
• Incidence of Clinical Neurological Events [Time frame: Periprocedural]
• Correlation Between Procedure Duration and Cerebral Microembolic Signal Burden [Time frame: Periprocedural]

Eligibility criteria

Inclusion criteria

• Age 18 years or older
• Severe symptomatic aortic valve stenosis
• Clinical indication for transcatheter aortic valve implantation
• Feasibility of transcranial Doppler ultrasound monitoring
• Signed written informed consent

Exclusion criteria

• Recent stroke or transient ischemic attack
• Significant cerebrovascular disease preventing reliable transcranial Doppler -assessment
• Previous aortic valve implantation
• Active endocarditis
• Pregnancy or breastfeeding

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Open label

Primary purpose

Treatment

Study locations

Croatia · 2 centers

• Sisters of Charity Hospital Zagreb — Zagreb
• UH Dubrava — Zagreb

Identifiers

NCT: NCT07614100 · 2026/0423-10

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗