In the five-year period since I learned that I have congestive heart failure I believe the doctors have taken more blood from me than they did in the first 56 years of my life. What is the reason for this increased interest in the substance that flows through my heart – although less efficiently than before?
In some respects, it is because the heart is the one organ that connects to every part of the body. While it is true that a healthy heart fuels the other organs and tissues in the body, an unhealthy heart can cause those organs and tissues to start to weaken. This means that my doctors must periodically perform basic or complex metabolic panels to check to see how my heart failure may be impacting my bodily functions, especially my kidneys. Why are the kidneys so important?
The British Heart Foundation website has a very good and practical explanation that I think everyone who drives and has experienced traffic delays can understand:
So how can the heart cause traffic congestion for the kidney? The BHF tells us that basically when the heart fails, the kidneys may suffer from the reduced supply of oxygenated blood. Then the BHF describes what is an unhealthy cycle. The heart failure will impair the hormone system regulating blood pressure. The hormone system will then kick into overdrive, trying to increase blood supply to the kidneys. The heart will then experience an increased workload as it is forced to pump against higher pressure in the arteries.
Heart doctors also have to consider the agonizing treatment dilemma of prescribing drugs that may compound the issue for the kidney. In an effort to decrease the fluid retention that may be making it harder for the blood to pump, the doctors prescribe diuretics. They also prescribe ACE inhibitors and beta blockers to treat other symptoms. But those drugs have a side effect that can adversely impact the kidneys. So this creates the need to periodically stick me with a needle and sample my blood in order to monitor the kidney function.
What blood tests will the doctor perform? The most common in my case appear to be the basic metabolic panel (BMP) and the comprehensive metabolic panel (CMP). What is the BMP? According to the INOVA hospital website, the BMP gives information about your body's metabolism, or how your body uses food for energy. It gives a snapshot of the health of your kidneys, your blood sugar levels, and the levels of key electrolytes, such as potassium and sodium. A basic metabolic panel test measures the levels of eight important things in your blood: calcium, carbon dioxide, chloride, creatinine, glucose, potassium, sodium and urea nitrogen, or BUN. Creatinine and urea nitrogen are markers for how well your kidneys are working.
The CMP includes all of the substances listed above plus the following substances: albumin, total protein, alkaline phosphatase, alanine amino transferase, aspartate amino transferase and bilirubin. Some of these are proteins, others are enzymes that have a role in liver or kidney functioning.
So my track record for two of the substances has raised eyebrows. First, I appear sometimes to be sodium challenged. This fact initially caused me some confusion, as I was told starting five years ago that I needed to drastically reduce my sodium. This is a goal that I successfully accomplished! But then a blood test showed that my sodium level was too low. You would think that the doctors would be high-fiving me and telling me that I could add salt back into my diet.
Alas, it doesn’t work that way. I think the reason for this is that as crazy as it sounds, it is likely that I am eating enough sodium. In case you doubt me, I found the following Q&A on the American Heart Association website: “Is there such a thing as eating too little sodium? The body needs only a small amount of sodium (less than 500 milligrams per day) to function properly. That’s a mere smidgen — the amount in less than ¼ teaspoon. Very few people come close to eating less than that amount. Plus, healthy kidneys are great at retaining the sodium that your body needs.”
I know that I get more than 500 milligrams of sodium a day. So instead of telling me to increase salt when my body’s sodium level dips, the doctors may instead tell me to do is decrease my water intake. Why? Because I likely have consumed a bit too much water and flushed sodium out of my body, thus diluting my body’s overall sodium level.
Second, the level of potassium in my blood can tend to be a shade high. So what is the concern? According to the Harvard Medical Publications website:
Consequently, I have learned which foods have a higher concentration of potassium. I try to never ever overload on these foods in one day.
You will not recall seeing “magnesium” as one of the substances tested by the BMP or CMP. This is a separate blood test that my doctor recently performed. So why conduct this separate test to determine magnesium levels in your blood. According to the information on my doctor’s office website:
Fortunately, the level of the magnesium in my blood was within the acceptable range. But I suspect my doctor will order this test periodically to make sure that it remains acceptable.
One blood test that is performed on some patients requires checking the levels of digoxin in the blood. This test is for patients who take the drug digoxin to treat heart failure or irregular heartbeats. Thankfully, I do not take digoxin. The drug contains cardiac glycosides. According to the website Healthline.com:
The bottom line is that the best way to monitor how my heart and heart drugs are impacting the rest of body is to periodically perform blood tests. Happily, I have never had a fear of needles. And even though my heart doesn’t pump blood through my body efficiently, there always seems to be plenty of blood available to fill numerous test tubes.
The technicians are always careful to ask which arm I prefer to have them use for the blood test. I tell them that it really doesn’t matter to me. I will also tell them to feel free to take as much as they need. But I will warn them that the one thing that they need to do is make sure that I do not see the blood coming out of my arm into the test tube. Even if I have been having a good day with no dizziness, I will probably hit the floor instantly if I see the blood flowing out of me. I suspect this is one of the many reasons that I chose to become a lawyer and not a doctor. Still a lot of Latin terms to manage, but at least no bloody incisions to perform on a regular basis!
Melanie discovered that she had heart failure in 2013. She spent the next 7 years learning how to live with the condition, and how to achieve balance and personal growth. Then in October 2020, she received a heart transplant. This blog is about her journey of the heart.