Transcatheter Aortic Valve Replacement (TAVR) & Stroke
Up to 7% of people have aortic stenosis (a narrowing of aortic valve opening). TAVR is indicated for patients with severe aortic stenosis who have immediate or high risk for stand valve replacement surgery. Since 2002, approximately 2000 TAVR were performed worldwide.
What is TAVR?
This minimally invasive surgical procedure repairs the valve without removing the old, damaged valve. Instead, it wedges a replacement valve into the aortic valve's place. (www.heart.org)
Stroke is the most scariest complication of this procedure is stroke. About 3-4 % of Stroke can occur during the procedure or post procedure up to 2 months. Patients with stroke have a higher chance of death compare to patients without a stroke.
The very challenging part is when they look at the MRI of the brain of those patients after TAVR, up to 90% of them have small silent brain lesions (infarctions). As of now, we do not have a long term data on these MRI findings & cognitive function.
We have indirect evidence from healthy elderly patients. People with silent brain infarctions have 3 times higher risk of stroke, greater decline in cognitive functions and 2 times more risk of dementia after a follow-up of almost 4 years.
Nevertheless, some patients with baseline cognitive impairment improve their cognitive function after procedure.
How to prevent stroke from TAVR ?
The patients need adequate blood thinner on board before and after the procedure. The doctor can use embolic protection device (EPD) to prevent the blood clot goes or tissue debris from the valve go up to the brain. In US, there is only one device available and approved by FDA (Sentinel). It is not 100% protection, it does not protect left vertebral artery and it can not prevent the emboli that is smaller than 140 micron. Luckily > 85% of embolic materials are larger than 1 mm. It is also depends whether it is placed properly.
What we know and what we don't know?
First of all, there are other devices for embolic protection. We don't have head to head data to compare which one is better. We don't have large sample size studies to prove the benefit of the stroke prevention by using the device yet. All we know from meta-analyses studies that EPD decrease volume of brain lesions. We need a long term studies on cognitive functions after TAVR.
Image from reference 4
Multiple silent emboli after TAVR
1) Cerebrovascular Events After Transcatheter Aortic Valve Implantation. Front. Cardiovasc. Med., 31 July 2018
2) Cerebral embolic protection devices during transcatheter aortic valve implantation: clinical versus silent embolism J Thorac Dis 2018;10(Suppl 30):S3604-S3613
3) Transcatheter aortic valve replacement and stroke: a comprehensive review. Journal of Geriatric Cardiology (2018) 15: 95-104
4) Swiss Med Wkly. 2012;142:w13735
Kessarin Panichpisal, MD.