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I read with great interest the article “Neurocognition and Cerebral Lesion Burden in High-Risk Patients Before Undergoing Transcatheter Aortic Valve Replacement: Insights From the Sentinel Trial” (1). I commend the goal of the investigators to try to minimize or eliminate zones of brain infarction (as seen by diffusion-weighted imaging lesions on magnetic resonance imaging) during transcatheter aortic valve replacement. It is also very useful that they attempted to determine the relationship of these new lesions with cognitive decline. However, they did not find a relationship with worsening cognitive deficit in patients with increased volume of these diffusion-weighted imaging lesions, because of what the investigators postulate may be a “floor” effect of the patient population (i.e., these patients were already compromised, such that any further decrease would be difficult to assess). Although this is almost certainly one of the factors, it is also important to view the data acquired.
The discrepancy in the device arm between protected territories of infarction and total volume of infarction, including unprotected territories (2) speaks volumes, literally and figuratively. If I subtract the median volume of infarction in the protected territories of infarction (102.8 mm3) from the median total volume of infarcted tissue in all territories (294 mm3), the difference is 191.2 mm3. Therefore, 65% of lesions were outside the protected territories. The device covers the innominate artery and left common carotid artery and thereby the right internal carotid artery, right vertebral artery, and left internal carotid artery territories, respectively. However, it does not cover the left subclavian artery, thereby leaving the left vertebral artery territory unprotected. Because most patients are either left vertebral dominant or codominant, this leaves not only the left vertebral artery territory at risk but the basilar artery and bilateral posterior cerebral artery territories at risk in most patients.
Using an analogy, to keep our homes protected from intruders, we not only lock the front and side doors but the back door as well. By leaving the back door (left subclavian and left vertebral arteries) open, we are allowing intruders (emboli) unfettered access to our home (brain).
Although it is possible that we may protect the whole brain and get similar results in terms of cognitive changes, we cannot blame everything on the “floor” until we lock all the doors.
Please note: Dr. Abrams is a consultant and holds stock options in Keystone Heart.
- 2018 American College of Cardiology Foundation
- Lazar R.M.,
- Pavol M.A.,
- Bormann T.,
- et al.
- Kapadia S.R.,
- Kodali S.,
- Makkar R.,
- et al.,
- for the SENTINEL Trial Investigators