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

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

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.

Study Overview

• Status: Not yet recruiting
• Conditions: Aortic Stenosis
• Intervention / Treatment: Device: Balloon-expandable transcatheter aortic valve; Device: Self-expanding transcatheter aortic valve

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.

• Study Type: Interventional
• Enrollment (Estimated): 80
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Mihovil Santini, MD; Phone Number: +385958101778; Email: 023miho@gmail.com
• Study Contact Backup: Name: Zeljković, PhD,MD; Phone Number: +385917823289; Email: ivanzeljkov@gmail.com

Study Locations

• Croatia
  • Zagreb, Croatia, 10000
    • UH Dubrava
  • Zagreb, Croatia, 10000
    • Sisters of Charity Hospital Zagreb

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Balloon-Expandable Valve; Participants in this arm will undergo transcatheter aortic valve implantation using a balloon-expandable transcatheter aortic valve. This valve type is a standard and routinely used treatment option for patients with severe symptomatic aortic valve stenosis. Cerebral microembolization will be assessed by transcranial Doppler ultrasound before, during, and after the procedure.	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.
Active Comparator: Self-Expanding Valve; articipants in this arm will undergo transcatheter aortic valve implantation using a self-expanding transcatheter aortic valve. This valve type is a standard and routinely used treatment option for patients with severe symptomatic aortic valve stenosis. Cerebral microembolization will be assessed by 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Number of Cerebral Microembolic Signals During TAVI	he primary outcome is the difference between study groups in the change in the number of cerebral microembolic signals detected by transcranial Doppler ultrasound before, during, and after transcatheter aortic valve implantation. The comparison will be made between participants receiving balloon-expandable valves and those receiving self-expanding valves.	Before, during, and immediately after the TAVI procedure

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Cerebral Microembolic Signals Within Each Study Group	Change in the number of cerebral microembolic signals detected by transcranial Doppler ultrasound before, during, and after TAVI will be assessed separately within each valve group.	Before, during, and immediately after the TAVI procedure
Distribution of Cerebral Microembolic Signals by Procedural Phase	The number of cerebral microembolic signals will be analyzed according to procedural phase, including instrumentation, valvuloplasty, valve implantation, and the post-implantation period.	During the TAVI procedure and immediately after valve implantation
Occurrence of New Cerebral Microembolic Signals After TAVI	he occurrence and number of new cerebral microembolic signals detected after completion of the TAVI procedure will be recorded and compared between the study groups.	Immediately after the TAVI procedure
Incidence of Clinical Neurological Events	The association between procedural characteristics, including procedure duration, vascular access route, predilatation, postdilatation, and procedural complications, and the number of cerebral microembolic signals will be assessed.	Periprocedural
Correlation Between Procedure Duration and Cerebral Microembolic Signal Burden	The correlation between procedure duration, measured in minutes, and cerebral microembolic signal burden, measured as the number of cerebral microembolic signals detected by transcranial Doppler monitoring, will be assessed.	Periprocedural

Collaborators and Investigators

• Sponsor: Ivan Zeljkovic
• Collaborators: University Hospital Dubrava; Sisters of Mercy University Hospital

Study record dates

Study Major Dates

• Study Start (Estimated): June 1, 2026
• Primary Completion (Estimated): January 30, 2027
• Study Completion (Estimated): February 1, 2027

Study Registration Dates

• First Submitted: May 16, 2026
• First Submitted That Met QC Criteria: May 21, 2026
• First Posted (Actual): May 29, 2026

Study Record Updates

• Last Update Posted (Actual): May 29, 2026
• Last Update Submitted That Met QC Criteria: May 21, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Aortic Valve Stenosis; Transcatheter Aortic Valve Replacement; Microembolism
• Additional Relevant MeSH Terms: Aortic Valve Disease; Cardiovascular Diseases; Heart Diseases; Heart Valve Diseases; Ventricular Outflow Obstruction; Aortic Valve Stenosis
• Other Study ID Numbers: 2026/0423-10

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No