How’s Your Boundary Function?

The scene above invites a revisit of Mending Wall by Robert Frost. Frost wrote the poem in 1914 drawing on his long-time experience as a resident of rural New England. Rhythms and ritual are central themes of the short poem just as pondering the work needed to maintain a healthy boundary is, including questioning the value of the border structures in the first place.

Make no mistake about it, in medicine boundaries are paramount to good health. If I could have only one area of focus to make my patients healthy I know exactly what I would choose. I would choose to focus on boundary function.

Skin and the digestive tract border intensely on the outer world and are the first things that come to mind. They are huge pillars of health. Lung health is another area where we border the environment robustly. The respiratory system has a critical role in health. Being sound with boundary function also points to our interpersonal life and emotional well-being, and these are equally influential for our health outcomes. However, there is another structure on my mind related to boundaries that is a large contributor to our health, maybe more so than any of these other areas. Wellness with this other boundary area gives us a central foundational stability when it’s healthy.

I am thinking of a massive organ called the endothelium (a major organ of the cardiovascular system). It is a thin skin, a single layer of cells, that lines the interior surface of blood vessels and lymphatic vessels. This cell layer forms the barrier between the inside of the vessels and the arterial wall. The endothelium is a barrier with many important functions; it:

  • keeps your blood moving smoothly, and constricts and dilates to regulate blood flow.
  • prevents clotting.
  • manages the amount of fluid and substance that goes into our tissues.

What you don’t want is for lipoproteins, specifically ones with apolipoprotein B (liporotein a, LDL, VLDL) to enter behind that skin and embed themselves in the arterial wall. This starts a cascade that leads to fatty streaks and lipid structures in the blood vessel walls. A good boundary always allows some passage back and forth. A healthy boundary breathes, but with an impaired boundary, things get stuck without flow. 

Dysfunction of the endothelium is paralleled by a hardening or stiffness in the function of the cardiovascular system, is a key event in the development of atherosclerosis, and is accompanied by an elevated risk of cardiovascular events. Lipoprotein can always pass through the endothelium, but the trouble starts when passage back out is impaired. Fluidity surrenders to rigidity.

I emphasize the sedentary nature of modern society as the main reason why cardiovascular disease is so common. Stiffening is aging and needs to be countered by moving, dancing, laughing, and playing. We are lopsided more and more.

Lack of movement and emotional stress are the main agents of the heart disease epidemic. They are like cement to the physical body.

CV disease is common, serious, and sneaky… and it starts young. Autopsy data reveals that up to a third of 16 – 20-year-olds who were examined after death for other reasons (accidents, homicide, etc) already have some atherosclerotic plaque. They weren’t considered to be in imminent danger from the arterial changes, but, notably, these changes were present. Heart attacks from blockages in arteries show up later in women than men, but a third of all heart attacks in women happen before age 65.

Half of all heart attacks in men happen before age 65 and a quarter of events happen before age 54.

I think the point here is that the process begins a long time before the event, and it can be sneaky.

The pathway is clear. We combine regular tests tracking cholesterol numbers with making sure metabolically we are dotting our i’s and crossing our t’s. That refers to many of those things that you know well:

  • eating well (monounsaturated fats like olive oil, avocados, and macadamia nuts keep the apoB levels lower compared with a diet high in saturated fats which raises apoB levels in patients about 30% of the time on a keto diet, for example).
  • blood pressure optimization
  • tobacco avoidance
  • exercise 
  • sugar and insulin measurement and management
  • stress management

The other aspect of the approach that can enhance these traditional measurements is to consider non-invasive cardiovascular assessments, specifically CT coronary calcium scoring or Carotid Artery CIMT Ultrasound. Over the years I have done more Ultrasounds with patients because they don’t have the small but significant radiation exposure the CT scans do. 

Screening is not for everyone. We would not screen low-risk patients or most people who we already treat aggressively (known heart disease). Generally, it is the intermediate-risk patients that may possibly benefit from the testing. The idea for this group is to let the results guide management. If we study a medium-sized artery in the neck (which is a strong predictor of the appearance of the medium-sized arteries in the heart) we can match the intensity of our approach to the findings. Now you have another layer of evaluation and data on which to rely.

The body is complex and difficult to predict. We can’t guess the degree to which processes are occurring in our cardiovascular system. Sometimes people with good lab numbers and only one or two risk factors will be revealed to be making significant plaque. And vice versa –> sometimes someone with numbers that aren’t very good in several categories will be clean on ultrasound. There are lots of factors. Often it is good to know what is there.

Screening Day for CIMT at BWH

We are setting up a visit from a national CIMT ultrasound screening group at the office later this winter for cardiovascular screening. Details to be announced. I am bringing them back (they have come before) because their quality is superior to the testing that is available in western Massachusetts currently. Interested parties can call us to be included.

Here is a review of some CIMT Ultrasound facts:

  • CIMT measures the thickness of the layers of the carotid artery wall beneath the endothelium using ultrasound. Thickness is a marker of subclinical atherosclerosis. This testing gives you a vascular age.
  • Thickened CIMT may identify asymptomatic patients at risk of future
    CV events and stroke.
  • The presence of carotid plaque is an absolute predictor of atherothrombotic event risk. This is also screened for with the testing.


  • Routine screening is not recommended by medical societies for all risk groups. Screening should be considered individually.
  • CIMT assessment can be considered in asymptomatic intermediate-risk patients to improve risk prediction.
  • Measurement of CIMT and plaque presence may guide management in select intermediate-risk patients.
  • Lifestyle modifications and risk factor control remain the first line for cardiovascular prevention and are still our approach if screening is not pursued.

The company we are having come is Cardio Risk, a well-established company focused on early detection and monitoring of cardiovascular disease–the number one cause of morbidity and mortality in the Americas and Europe. They provide proprietary ultrasound image scanning, and processing, using FDA-cleared equipment, patented software, a nationally recognized screening protocol, and a highly trained staff validated to the most rigid scientific methodologies and quality standards. This helps to minimize variability in the test.

I will make an announcement when we set the date. It’s part of an effort to offer relevant and forward-reaching assessments that can empower our approach through knowledge. We are also exploring nutritional analysis protocols, genetic evaluations, body composition assessments, and next-generation cancer screenings that are part of a changing face of medicine. More to come on these if they prove ready for general consumption. The information age is shifting into the next gear. We have to keep at it, pounding the pavement every day in search of the latest developments.

Regular rest periods are encouraged.