The Carotid Artery

Q: Perhaps you will have an answer for this, to me, pressing question. Stent placement in one or both carotid arteries has become more and more common. How does this impact the baroreceptors ability to reduce blood pressure during inversions? If you have a stent, what are the limitations on practicing inversions? Should they be only mild, or are moderate or full okay for limited duration? If so, about how long/ Is it ever safe to practice full inversions after a stroke? 

A: Before discussing whether or not to practice inverted poses with this condition, let’s start with discussing the “what” and the “why” of stent placement in the carotid artery. Just as you can develop narrowing of and blockages in the arteries around the heart (coronary artery disease, which can cause heart pains and lead to heart attacks), you can also develop narrowing of and blockages in the main arteries to the brain, the carotid arteries, located in the neck. In many cases, experiencing a stroke or mini stroke is the first indication you may have such a blockage. Carotid artery disease can also lead to gradual cognitive changes and contribute to the development of dementia, even in the absence of stroke. 

For a long time now, the main way of opening these blocked arteries back up when they become significantly closed was to do a surgical procedure called carotid endarterectomy, where the vessel is opened up and the blockage is removed. This is a major neck surgery done under general or regional anesthesia. As our reader points out, there is now a newer and less invasive technique that does not requiring anesthesia called carotid artery stent placement. Similar to the method used for stent placement in the vessels of the heart, with this technique a catheter is inserted into a major blood vessel in the groin area and threaded up into the carotid artery where the narrowing or blockage is, and a stent is placed there, which expands outwards to reopen the blocked passage. 

Typically, you would undergo one or the other of these procedures if you had signs and symptoms of narrowing of the arteries or had already suffered a stroke, leaving you at risk of having a first or repeat stroke if left untreated. Often, patients in this situation have multiple other health issues going on, such as high blood pressure, diabetes, high cholesterol, history of smoking, and other heart issues, and with that are often on multiple medications to try to address said problems. So, this can be a more complex issue than simply having one blocked blood vessel, making it difficult to generalize how this may impact your yoga practice. 

Now, let’s assume you have had a stent placed in one or both carotid arteries. What is the effect on the functioning of the baroreceptors in that neck region and how might that impact blood pressure after the patient has healed from the procedure? (I am not going to go into detail on the effects during or right after such a procedure, since I am assuming this reader has successfully undergone stent placement and is now returning to regular activities.) It turns out that for some people their blood pressure ends up lower after the procedure! This may be a result of the outward pressure of the stent stimulating the baroreceptors to respond as if the blood pressure is higher, which in turn causes the brain to lower the blood pressure in response. 

This effect has been seen to persist for up to a year in those who respond this way. In many cases, these folks can lower their dosage of high blood pressure medications. It also is known that even a slight decrease in blood pressure lowers the chances of stroke down the road, so people who have decreased blood pressure after stent placement have a reduced long-term risk of stroke. In addition to the lowering of blood pressure seen in some patients, baroreceptor sensitivity usually returns to normal six months after a stent placement for those with or without the blood pressure changes noted above. So, all the baroreceptors, both on the aorta and in the carotids, would detect changes in blood pressure in a healthy way, leading to normal responses by the brain. 

That said, I was not able to find any studies looking at the ability of the baroreceptors in someone who has had a stent placed to lower blood pressure in yoga inversions. So, as always, and especially in complicated medical conditions like this, it is essential that you discuss with your specialist doctor to get their recommendations regarding cautions in your yoga practice. 

I did ask cardiologist friend of mine what his recommendations might be for reintroducing inversions into a yoga practice in this particular situation (realizing that his recommendations are not applicable to individual cases without seeing the patient for an evaluation). Fortunately, he has some basic understanding of yoga poses and practices. His recommendation was clear: If the person had already had a stroke, he said to avoid inversions, as the risks—which include worsening the stroke or precipitating a new one, as well as possible dizziness and fainting—outweigh the benefits. In fact, he is quite conservative when it comes to patient care for anyone who has already developed carotid artery disease, as it means there could already be changes to blood vessels in other areas, especially possible changes to the flow of blood in small vessels of the brain, and this puts folks at risk of bad outcomes. He’d recommend skipping them altogether, as he feels the risks outweigh any benefits of doing inversions, and focus on the non-inverted poses and other seven limbs of yoga instead. 

Of course, it is possible your physician will have a different take on the risk/benefits of reintroducing inversions in this situation. So, for those who get the okay from their health care team to reintroduce inversions, I recommend you begin with the more gradual and/or supported inverted poses. 

For those that can be done dynamically, such as Downward-Facing Dog pose and Bridge pose, start there and see how your body handles them before holding them statically. Make sure there is no dizziness, lightheadedness, rapid heartbeats, sudden headaches, or anything else that feels like a worrisome response to inverting. After practicing the dynamic version for a period of time and feeling acclimated, you can introduce short holds of 15-30 seconds, coming out of the pose for a few breaths, and possibly repeating it a second time, assessing your body’s response as with the dynamic versions. Over time, you can gradually add more time in the pose as tolerated. You can also use dynamic poses to prepare for a pose that can only be done statically. 

You can also gradually work your way up to a classic supported inverted poses by first practicing some dynamic poses and then practicing the most gentle variation of the inverted pose and work your way up to the full pose. For example, let’s take one of my favorite supported inversions, that is generally safe for most practitioners in most situations, Legs Up the Wall. 

For example, to prepare for classic Legs Up the Wall pose, you could do the following sequence: 

1. Use Dynamic Upside-Down Downward-Facing Dog pose to prepare your body for the general shape of the pose without having to hold it (see youtube.com ). 

2. From there, you would progress to the most gentle version of Legs Up the Wall pose, where your pelvis is on the mat and your calves are resting on the seat of a chair. (We sometimes call this Relaxation pose with a chair or Easy Inverted pose.) 

3. You can then progress to the version where your pelvis is on a bolster and your legs are on the chair. 

4. Eventually, you could progress to the classic version of Legs Up the Wall pose, with your pelvis elevated on a bolster and your legs up the wall (for instructions, see Featured Pose: Legs Up the Wall Pose ). 

You could take a similar approach to classic Downward-Facing Dog pose: 

1. Begin with Dynamic Downward-Facing Dog pose (see youtube.com). 

2. Move to short holds of the chair version of Downward-Facing Dog pose (see Featured Pose: Downward-Facing Dog Pose). 

3. Finally, practice the full pose (see Featured Pose: Downward-Facing Dog Pose). 

Finally, if you are told that inversions are too risky for you at this time, remember that there are other yoga tools you can practice to access one of the main benefits of inversions, the triggering of the relaxation response. See Nina’s post The Relaxation Response and Yoga to learn more. 

By the way, this is the second Friday Q&A regarding the practice of inverted poses with a specific health condition. see Friday Q&A: Pituitary Tumor and Yoga for the first one.

—Baxter

Follow Baxter Bell, MD on YouTube, Facebook, and Instagram. For upcoming workshops and retreats see Baxter’s Workshops and for info on Baxter see baxterbell.com.  


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