Hey guys, this is my first fan post. I've been a part of this community for the past few months and finally feel like I have something to contribute. First, a little bit of background, I was born and raised in CO and have bled blue and orange my whole life. Currently I am a 2nd year medical student out on the east coast and yes I still have CO tags on my car. Coincidentally I have my cardio/pulmonary pathology exam tomorrow so I thought I would take a few minutes and write out a post talking about the differential diagnosis that we could be dealing with in terms of Foxy's heart. I won't be able to speak too specifically regarding how it's treated and what the post-operative care will entail (that's a bit above my pay grade right now). To be clear, I am not affiliated with the Broncos or the hospital treating him. I know nothing of his personal medical history and this is all purely speculation based on what I've read.
First, a bit about heart anatomy. We all know that the heart has 4 chambers: 2 atria and 2 ventricles. These chambers are separated by valves which allow for unidirectional flow from the right side of the heart, through the lungs, to the left side, and out through the aorta to the body. According to the press release Coach Fox will be having an aortic valve replacement done.
The aortic semilunar valve has 3 leaflets and sits within the aorta at the junction between the aorta and the heart. It is meant to deal with the substantial pressures of the systemic circuit (body) when blood is not flowing through it. The aortic valve is incredibly important because it prevents blood flow back into the heart while the heart is relaxing (during diastole). In about 1% of all adults the aortic valve has only 2 leaflets instead of the normal 3 (more on this in a bit).
Calcific Aortic Stenosis (CAS) - when it comes to needing to replace an aortic valve this is at the top of the list. CAS is the most common of all valvular abnormalities. It is a "wear and tear" type of condition that usually presents in the 60 - 80 year old population (I'll get into pathophys in a bit). Roughly 2% of the population experiences this condition.
Now, if you're asking yourself "isn't Coach Fox a little young for this?" you're right. However, remember that 1% of all people with only 2 leaflets in their aortic valve? That's the kicker. About half of all aortic stenosis cases are due to a bicuspid aortic valve. Individuals with this condition usually become symptomatic in their 50-70s. Remember, even though we're dealing with very small percentages of the population, this is the most common reason for aortic valve replacement. My guess is this is the reason Coach Fox requires the procedure. This is a very slowly progressing condition which is why he could have a consultation for it in October with a procedure date in March.
If we were playing the odds and taking the story at face value we'd stop there at CAS. However, this being a differential we have to talk about a few other causes. Here are some other reasons why an aortic valve could need to be replaced.
Aortic Insufficiency (regurgitation) - here's another one which is not impossible and can present with light headedness. Aortic insufficiency is when the valve leaflets fail to close properly and allow back-flow of blood into the heart. It can be caused by damage to the leaflets from infection such as endocarditis (infection of the inside of the heart), or more dramatically aortic dissection. Given the fact that Coach Fox was so relaxed and "oh darn" about this situation I wouldn't think aortic dissection was not the cause. That's a medical emergency and those patients present with a whole litany of risk factors and conditions. He was on the sidelines last week and there was no emergent rush here. He knew this was coming, aortic dissection isn't something you really plan for. It can blindside you.
The most common cause of aortic insufficiency is isolated dilation of the "root" of the aorta. The root of the aorta is where it comes out of the heart. If you dilate this, you make the diameter of the lumen bigger which pulls the leaflets apart and can prevent them from closing fully allowing back flow. The treatment is a valve replacement once left ventricular dysfunction develops. That could be the "lightheadedness" Foxy was hospitalized with so this is not outside the realm of possibility.
Chronic Rheumatic Heart Disease - although rare in this country because of our access to medical care, Rheumatic Heart Disease can be responsible for aortic valve problems. Rheumatic fever is a complication of strep throat infections. Essentially the chronic form is the result of many repeated rheumatic fever attacks. This condition mainly affects the mitral valve (the valve between the left atrium and left ventricle) with about 25% of all cases involving the aortic valve as well. It is responsible for ~10% of all aortic stenosis cases. It also presents with a whole host of other problems which make it a more serious condition. Given the team's stance and the fact that Coach Fox wasn't morbidly sick, I think this is low on the list.
The Pathophys: How did this happen?
For those of you who aren't interested in what's going on to cause CAS go ahead and skip this section. However, I'll keep it brief. Essentially what's going on with CAS is you have atherosclerosis of the valve. Atherosclerosis begins with a defect in an artery or valve or anywhere on the inside of your circulatory system. This kicks off an inflammatory process where a lot of molecular stuff happens. Cholesterol, white blood cells, and other factors can accumulate and form plaques which can calcify (like bone) and make the arteries or valves hard and crusty. Plaques can also alter the lumen of the vessel altering the flow of blood through it which can further exacerbate damage to the lining of the vessel and round and round we go.
Individuals who have bicuspid aortic valves are more susceptible to CAS because they have 2 leaflets doing the work of 3. That means more stress per leaflet which leads to injury sooner and kicks off the process. It should be noted that the "injury" I am talking about does not have to be dramatic. Disruption of a few cells can kick off the process. Blood is viscous and full of stuff that can bump and scrape along the walls to initiate this process. Atherosclerotic precursor lesions (fatty streaks) get started early and are seen in teenagers. This is a very slowly progressing process.
First off, it is really good that Foxy is taking care of this because untreated CAS can progress to congestive heart failure and death. The main complication with CAS is when you narrow the valve the heart has to work harder to push blood through it. This forces the left ventricle to get thicker with muscle to work against the higher resistance. If the wall grows too thick it can outgrow its blood supply and cause a myocardial infarction or heart attack. This can also lead to back up of blood into the left atrium, lungs, and right side of the heart. When that happens you have full blown congestive heart failure and the prognosis is very poor (50% 2-yr survival rate).
Additionally when you have blood flowing through a stenotic valve it's very turbulent. Think of when you put your thumb on the end of a hose. That turbulence can cause damage to red blood cells and cause it to clot up leading to things like strokes.
Here is where my knowledge becomes severely limited. The #1 treatment for this is of course a valve replacement which we know Foxy is getting. To my knowledge the prognosis is pretty good because we know a lot about the procedure and what to watch out for. He will need to be on an anticoagulant like Warfarin which has its own risks. Additionally artificial valves can act as seeds for infection by some bacterial species. These things will need to be watched for closely and the 4-6wk timeline makes sense.
Even though we know a lot about the procedure and understand it well this is still open heart surgery and carries risk with it. The good news is that he seems otherwise healthy, hopefully without diabetes or at least controlled diabetes.
Here's hoping for a speedy and successful recovery Coach Fox. I'm excited to watch how our team responds!
Disclaimer: these comments were not posted by a licensed medical professional. They should not be used for any type of diagnostic or therapeutic purpose. If you have any questions regarding your current health you should contact your healthcare provider.