Brian Lacy, MD, and David Tendler, MD, on Vascular Disorders of the GI Tract

Drs Lacy and Tendler discuss some of the more common vascular disorders seen in the gastrointestinal tract and how they are diagnosed and treated.

Brian Lacy, MD, is a professor of medicine at the Mayo Clinic in Jacksonville, Florida. David Tendler, MD, is a clinical associate at Duke University in Durham, North Carolina.

Check out Dr Lacy and Dr Tendler's podcasts on mesenteric ischemia here and here. 

TRANSCRIPT:

Dr. Brian Lacy:  Welcome to this Gastroenterology Learning podcast. My name is Brian Lacy. I'm a professor of medicine at the Mayo Clinic in Jacksonville, Florida. I am delighted to be speaking today to Dr. David Tendler, clinical associate of medicine at Duke University in Durham, North Carolina.

Last month, we had a wonderful discussion with Dr. Tendler on mesenteric ischemia. Our topic today is one that is frequently discussed when evaluating patients with chronic nausea and vomiting, or chronic abdominal pain—vascular disorders of the GI tract.

Dr. Tendler, welcome again. Let's begin by talking about celiac artery compression syndrome, also called median arcuate ligament syndrome. It's a bit of a controversial area, but before we get to that controversy, we'll put our listeners on hold for a second.

Can you explain the anatomy of this disorder to our listeners and why this might develop?

Dr. David Tendler:  Sure. First of all, thank you, Dr. Lacy, for having me back. I'll interpret that as a good sign. I appreciate the opportunity to discuss the topic.

To address your question, median arcuate ligament syndrome, which is a relatively uncommon cause of chronic mesenteric ischemia, is caused by compression of the celiac artery by the median arcuate ligament of the diaphragm.

The median arcuate ligament is an arched‑shaped fibrous band that bridges the crura of the diaphragm, typically above the level of the celiac axis, although the anatomy can vary. Because of that, variations neither at the position of the ligament or the branch point of the celiac axis coming off the aorta, there can be compression of the celiac artery.

Dr. Lacy:  What are the risk factors for developing this disorder? Which populations are at risk? Is it just women? Is it just tall women?

Dr. Tendler:  The main risk factor is being relatively thin women, generally in the 40 to 60 age range. That is certainly the population most affected by the condition. It does affect women in about a 4 to 1 ratio to men.

Dr. Lacy:  Thinking about symptoms, what are the typical symptoms our listeners should be thinking about, and what should they be aware of?

Dr. Tendler:  Just like we discussed last time, with respect to chronic mesenteric ischemia, the symptom complex is similar, which is comprised primarily of postprandial abdominal pain, nausea, vomiting, and the development of a food aversion, which then leads to weight loss. Bloating is also a commonly reported symptom in about 30 to 40% of patients.

On exam, an abdominal bruit may be appreciated, particularly during expiration. In terms of other symptoms that may turn up, patients will sometimes report some relief of symptoms by bending forward or bending the knees at the waist.

Dr. Lacy:  Wonderful. Two great tips for our listeners there. One is a quiet room. Listen carefully in the right upper quadrant for that bruit. Then, some patients will tell you how to lean forward on a chair or lean over, and they seem to get some relief after eating.

We started this conversation by me saying this is a controversial area, because we know from some autopsy studies and also radiologic studies that celiac artery compression can occur in some patients, but they don't have any symptoms. Why do you think this is? What's your take on that?

Dr. Tendler:  This definitely is a controversial topic, and truthfully, it's not, even now, been well‑ironed out. It's unlikely that compression of the celiac artery alone is enough to cause this syndrome, given the collateral circulation of the SMA [superior mesenteric artery].

As you alluded to, it's also been shown on imaging studies primarily that about 7 to 10% of the population may have asymptomatic evidence of celiac artery compression on imaging, and about half of those compressions are due to compression at the level of the median arcuate ligament.

Most of those patients will not go on to have chronic symptoms. Given all that, it's been proposed that compression of the celiac nerve plexus, along with the artery itself, may be a significant contributor.

Dr. Lacy:  Absolutely. That's wonderful. Thank you. When we think about celiac artery compression syndrome, or median arcuate ligament syndrome, at least the way I practice, I consider this as one disorder among others. It can mimic gastroparesis. What other disorders should our listeners think about, in terms of a comprehensive differential diagnosis?

Dr. Tendler:  Certainly, there are many more common conditions that can lead to similar postprandial symptoms, which you touched on gastroparesis, of course, peptic ulcer disease, atypical gastroesophageal reflux symptoms. Gallbladder disease certainly can cause postprandial pain and nausea.

Small‑bowel Crohn's disease, particularly if there's luminal compromise, can give you obstructive symptoms that can be very similar symptom‑wise, in terms of producing postprandial pain. Then, in the appropriate patient, chronic pancreatitis.

Dr. Lacy:  Maybe for our listeners, too, think about that patient with dyspeptic symptoms if you're thinking about the Rome criteria for functional dyspepsia. David, what tests are required to accurately make the diagnosis of celiac artery compression syndrome?

Dr. Tendler:  Cross‑sectional imaging with CT or MR angiography is the gold standard right now for looking for evidence of celiac artery compression. While not critical, in cases where there's still uncertainty remaining, the diagnosis can be confirmed with additional vascular imaging with respiratory maneuvers.

Both Doppler ultrasound and conventional angiography, both can show diagnostic changes in respiration‑induced flow velocities. The modality of choice, of course, is somewhat dependent on the expertise of the institution.

Dr. Lacy:  Wonderful. Thank you. Surgery, part of our jobs is oftentimes to keep patients away from surgeons, but surgery, in this case, transection of this fibrous band of tissue is considered the most comprehensive therapy. In your opinion, having done this job for years, how successful is this, and do we have predictors of response?

Dr. Tendler:  While the primary intervention is decompression of the celiac artery by releasing the ligament, usually that's done along with a concomitant ganglionectomy, and that combined artery release, and addressing the release of the plexus of nerves has a success rate that ranges depending on the series that you look at, anywhere from 40 to 55%.

Then, combining the artery release with revascularization then improves long‑term success rates by approximately another 25%, upwards of 80% of people. To that end, intraoperative ultrasound may help identify those patients who can benefit from revascularization.

This is generally an indolent progression, and if patients do remain symptomatic afterwards and they haven't been revascularized, certainly that could be pursued subsequently.

Dr. Lacy:  That's wonderful. I like your teaching point there, too, that sometimes, simply releasing that ligament, restoring blood flow is not enough because the celiac plexus is right next door and maybe that was injured. This is great.

Let's shift gears now and let's consider another vascular disorder of the upper GI tract that clinicians often consider. SMA syndrome or superior mesenteric artery syndrome. How common is this?

Dr. Tendler:  This is another relatively uncommon condition, in terms of those that will cause proximal small‑bowel obstruction. The SMA syndrome does lead to intermittent obstruction of the proximal small bowel, usually at the level of the third part of the duodenum. As far as vascular disorders of the upper GI tract, it is relatively uncommon.

Dr. Lacy:  Which population is most at risk? For some of our listeners who like medical history, they may recall that this was originally described in patients who were in full‑body casts and lost a lot of weight. Is this the only group we need to be worried about, just those who have lost weight?

Dr. Tendler:  That seems to be a fairly reproducible finding. Significant weight loss does seem to precede a lot of the reported symptoms. Presumably, that's due to loss of the mesenteric fat pad during profound weight loss that ordinarily helps to preserve that normal angle between the SMA and the aorta. When that angle becomes more acute, the duodenum can become compressed.

Dr. Lacy:  Perfect. Great anatomy. What are the typical symptoms of SMA syndrome? Are they highly sensitive and specific? Do you think that maybe this is a condition that is sometimes overlooked?

Dr. Tendler:  No doubt, it's overlooked, because the symptoms are those of proximal small‑bowel obstruction. Postprandial pain, usually within about 30 to 60 minutes of eating, nausea, vomiting, abdominal distention. It's easy to overlook them because there's clearly more common causes of bowel obstruction.

The symptom complex is certainly not specific for SMA syndrome. In a patient that has had those other common culprits ruled out and may have had that red flag symptom of antecedent weight loss as part of the history, that's the time to think about SMA syndrome.

Dr. Lacy:  Wonderful. When we were discussing celiac artery compression syndrome, you mentioned mesenteric duplex and cross‑sectional imaging. Let's think about SMA syndrome and the diagnosis. What's the best diagnostic study to confirm that diagnosis if you're thinking about it?

Dr. Tendler:  In this situation, you're looking to examine the caliber of the small bowel at the level of the third part of the duodenum. You're looking to have some form of a contrasted study that's able to characterize the caliber of the lumen of the duodenum. Either an upper GI barium series or CT with oral contrast.

Typically, you'll see a dilated proximal duodenum that transitions to a normal caliber past the third part of the duodenum.

Dr. Lacy:  For our listeners who may not have seen such an image, it can be striking, can't it, where you see this dilated second portion of the duodenum, even sometimes up to the bulb, and then it becomes more normal in caliber. It's impressive.

Dr. Tendler:  That's right.

Dr. Lacy:  Thinking about treatment options, do we have a specific treatment option for SMA syndrome? Is there some validated stepwise approach that you like to employ?

Dr. Tendler:  Yeah, there is. Unlike the case with celiac artery compression syndrome, surgery is not always necessary. The initial management involves nutritional support, caloric support, and with the goal of gaining weight, which can then lead to normalization of the mesenteric fat pad and resumption of that normal SMA aorta angle.

Positional changes of the patient could be helpful, also alleviating symptoms to their prone or left lateral decubitus position, which can alleviate pressure on the duodenum. Surgery is reserved for patients with persistent symptoms, and that usually involves decompression with duodenojejunostomy when symptoms are remaining.

Dr. Lacy:  You made a great teaching point again, David, that nutrition first, calories, work with a nutritionist, try to get that weight back on, and set surgery side. Let's not look for quick fixes. Finishing up this discussion, are there any other common vascular disorders of the GI tract our listeners should be aware of?

Dr. Tendler:  Looking back towards our last discussion, the more common chronic vascular disorders of the small bowel, the atherosclerotic disease, disease of the mesenteric vessels are still the more common means of getting chronic mesenteric ischemia.

Like we touched on, when 2 or more of the 3 main mesenteric arteries become more than 70% stenosed, and you get that classic triad of chronic mesenteric ischemia symptoms — postprandial pain, food aversion, and weight loss — then that's going to be the more common of the vascular disorders that we'll see.

The main point to consider relates to the patient's risk factors. In the younger, thin patient who may not have vascular disease risk factors but have symptoms of chronic mesenteric ischemia, that's when we think about median arcuate ligament syndrome or SMA syndrome.

The older patient with vascular risk factors, the traditional chronic mesenteric ischemia issues take center stage. That's more likely to be the culprit and should be thought of before it culminates in acute thrombotic ischemia.

Dr. Lacy:  Wonderful. That great history trying to categorize patients based on prevalence, but risk factors can lead you down the correct pathway. Very nice. I like that.

David, once again, this has been a wonderful conversation. I can't thank you enough. Our listeners I know are very appreciative. Any last thoughts for our listeners?

Dr. Tendler:  Again, take a good history. Consider the individual patient's risk factors, think of chronic mesenteric ischemia in the appropriate patient that has postprandial pain, food aversion, weight loss, that those symptoms remain unexplained, despite an appropriate evaluation to rule out the more common culprits.

As long as it's in your stream of consciousness, good outcomes are likely.

Dr. Lacy:  Dr. Tendler, once again, thank you so much for your great expertise. To our listeners, thank you for tuning in today, and we look forward to having you join us for another Gastroenterology Learning Network podcast in the future.

Dr. Tendler:  My pleasure. Thank you for having me, Brian.