Aortic Valve Stenosis, Silent Cerebral Infarct, Stroke, Vascular Brain Injury
Conditions
Keywords
Stroke, Aortic Valve Stenosis, Silent Cerebral Infarct, Vascular Brain Injury, TAVI, Transcatheter aortic valve implantation, Transcranial doppler, Magnetic resonance imaging, CO2, Carbon dioxide
Brief summary
The study aims to evaluate the processes of a pilot single-centre randomised controlled trial (RCT) of carbon-dioxide flushing of transcatheter aortic valves (TAVI-CO2) versus standard saline flushing of valves (TAVI-S) and assess potential neuroprotection through a number of neurological endpoints for planning of a full-sized RCT
Detailed description
Aortic stenosis (AS) is one of the most common valve diseases and is increasing worldwide due to an ageing population. Transcatheter Aortic Valve Replacement (TAVI) is a keyhole procedure that can be done through the groin to replace the narrowed aortic valve with a new valve, avoiding the need for cardiac surgery.Improved device design and greater operator experience has improved TAVI outcomes. It has become the standard treatment option in patients who are at high risk for cardiac surgery and is now being used increasingly in lower risk patients. Cerebrovascular accidents in TAVI patients remain a significant risk with a reported 3 - 5 % risk. Furthermore, these patients have neurovascular injury that is not clinically identifiable. Covert brain injury has been identified to occur in many surgical and cardiovascular catheter-based interventions such as TAVI and can cause vascular brain injury (VBI). TAVI valves are manufactured in room air conditions and retain air. Studies in TEVAR (Thoracic Endovascular Aortic Repair) stent grafts have shown release of air when they are deployed in the aorta. In vitro testing of TAVI valves has shown release of air when they are deployed. Carbon-dioxide (CO2) is 1.5 times denser than air and can displace it. It is 25 times more soluble in blood than air and does not lead to bubble formation. Hence CO2 bubble are unlikely to result in significant damage. CO2 has been used in cardiac surgery with beneficial effects. It has shown to reduce peri-procedural cerebral air embolisation and post operative cognitive dysfunction. This study aims to look at the neuroprotective benefits of flushing TAVI valves with CO2 and saline versus saline only by reducing air embolisation. Patients undergoing TAVI will be approached to participate in this study. After consent is obtained, patients will undergo baseline MRI, neurological and neurocognitive testing pre-TAVI. Patient will be randomised to saline only or CO2 and saline flushing of their valves. During their TAVI procedure, they will have transcranial doppler (TCD) monitoring of their middle cerebral artery (MCA) bilaterally to record cerebral embolisation. Patients will also have biomarker testing pre-TAVI, post-TAVI and 24 hours following TAVI. They will have DW-MRI brain between day 1-7 following their TAVI to look for vascular brain injury. Thus MRI will be repeated at 6-months following their TAVI. Patients will also have neurological and neurocognitive testing during their inpatient admission, at 6-weeks and 6-months outpatients.
Interventions
OTHERCO2 and saline flushing
TAVI valves will be prepared by flushing with CO2 to displace any retained air during manufacturing and preparation. The valves will then be flushed with saline as per IFU.
OTHERSaline flushing
TAVI valves will be flushed with saline only as per IFU.
Sponsors
Imperial College Healthcare NHS Trust
Imperial College London
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
DOUBLE (Subject, Outcomes Assessor)
Masking description
Patients and outcome assessors will be blinded to intervention.
Intervention model description
Patients will be randomised to CO2 and Saline flushing versus saline flushing only.
Eligibility
Sex/Gender
ALL
Age
18 Years to 100 Years
Healthy volunteers
Yes
Inclusion criteria
* All patients between the ages of 18 and 100 years undergoing transcatheter aortic valve implantation (TAVI) for aortic stenosis under local anaesthetic.
Exclusion criteria
* Patients that lack capacity to provide informed consent * Patients that have had a stroke within 12 months * Patients aged less than 18 years of age * Patients that are pregnant
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Number of participants suitable for recruitment for larger RCT | Duration of study, approximately 15 months | Conduct an evaluation of the processes described in this pilot RCT for a full-scale RCT including: 1. Screening, Recruitment and Randomisation 2. Retention in follow-up assessments 3. Study design for a full RCT and identification of important stratification variables 4. Refine sample size calculation for a full RCT |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Incidence of Vascular Brain Injury (VBI) on Diffusion Weighted-Magnetic Resonance Imaging (DW-MRI) | Post TAVI 1-7 days and 6-months post TAVI | Assessment of the incidence of DW-MRI detected VBI lesions following TAVI procedure. Patients will have MRI following their TAVI within 1-7 days and then at 6-months post TAVI. |
Other
| Measure | Time frame | Description |
|---|---|---|
| Detection of periprocedural cerebral solid and gaseous emboli | During TAVI procedure | Document the overall rate of periprocedural cerebral solid and gaseous embolisation by transcranial doppler (TCD) monitoring during the TAVI procedure. |
| Neurological deficit | 6 Months | Patients will undergo neurological assessment pre TAVI (baseline), post TAVI as inpatient, at 6-weeks and 6-months following TAVI. |
| Inflammatory biomarker assessing brain injury | 24 hours post TAVI | Serial measurement of pro-inflammatory biomarkers pre-operatively, at the end of procedure and 24 hours post-operatively as a marker of brain damage including S100B |
| Neurocognitive decline | 6 Months | Patients will undergo neurocognitive assessment pre TAVI (baseline), post TAVI as inpatient, at 6-weeks and 6-months following TAVI. |
Countries
United Kingdom
Contacts
Primary ContactSaud Ahmed Khawaja, MBBS
Backup ContactGhada Mikhail, MD
Outcome results
None listed