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

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.