How Can ACE Inhibitors Help Improve Your Life If You Have Heart Failure?

Heart failure is a chronic, progressive condition in which your heart isn’t pumping blood as well as it should. One of its characteristics is congestion, or fluid build-up, in your tissues and the veins in your lungs. That leads to symptoms that interfere with your everyday life and make normal functioning much harder.

Why is it important to regulate blood pressure in heart failure, and how is it done?

Our bodies have developed mechanisms for regulating virtually all processes at work in them, from the smallest ones to the ones that affect the whole organism, as your blood pressure does. The maintenance of normal blood pressure happens as a complex interplay between hormones, the brain, and the kidneys.

Your blood pressure rises when your blood vessels get constricted (narrowed). Your heart then has to work extra hard, just like you’d need to push harder to move fluid through a narrow pipe than through a wider one.

As you may imagine, when the heart is already damaged and not working as well as it should, putting extra strain on it makes things much worse. One of the important systems for regulating how wide your blood vessels are is called the renin-angiotensin-system (RAS), and it’s what ACE inhibitors act on.

So how exactly do ACE inhibitors work?

ACE inhibitors are substances that inhibit the enzyme (abbreviated ACE) that converts hormone angiotensin I to angiotensin II. Angiotensin I is made when renin is released in the blood, which happens when the blood flow in the kidneys is reduced. We don’t really know what angiotensin I does. But when it reaches the angiotensin-converting-enzyme, it’s transformed into angiotensin II, a hormone that acts on the blood vessels, the brain, and the kidneys all with one goal: to raise your blood pressure. 

If we block this enzyme from making angiotensin II, all of that could be avoided... But when we interfere with the natural regulatory mechanisms, it’s always important to be attentive to other consequences.

The effects of angiotensin II that we want to block are:

• Effect on the cardiovascular system. By binding to receptors on blood vessels, it directly causes them to constrict. 
• Effects on the brain. It increases thirst, causing you to drink more fluids. More fluid = higher blood pressure. Additionally, it causes the pituitary gland to release a hormone (ADH) that causes water retention. Sometimes it also causes low sodium levels, which was linked with a higher death rate in heart failure patients.Another significant effect of ADH is that it stimulates the production of yet another hormone, noradrenaline. This hormone is much like adrenaline, and it also constricts the blood vessels and acts on renin, a signal for the body to make more angiotensin I... And so the cycle continues.
• Effects on the kidneys. Angiotensin II really does a lot of things there, but what’s important for this discussion is that it causes sodium retention. Sodium really likes water and sticks to it, so in this way, water is also retained, again causing higher blood pressure.

ACE inhibitors prevent all of these effects. In addition, they increase the concentration of bradykinin, which widens the blood vessels. However, especially due to their effect on kidneys, there are things you need to be extra careful about when starting on these meds.

What are some commonly used ACE inhibitors?

Many drugs belong to the ACE inhibitor class. The main difference between them is how long they act, which also dictates how frequently you take them.

Some commonly prescribed ACEI are:

• Captopril (Capoten)
• Enalapril (Vasotec)
• Fosinopril (Monopril)
• Lisinopril (Prinivil, Zestril)
• Perindopril (Aceon)
• Quinapril (Accupril)
• Ramipril (Altace)
• Trandolapril (Mavik)

Things you need to be extra careful about when taking ACE inhibitors

• Your diet. Managing heart failure usually involves lowering your salt intake, and some people reach for salt substitutes. However, these are rich in potassium. ACE inhibitors already make your body retain potassium, so adding extra could lead to an abnormally high level of potassium in your blood (hyperkalemia).
• Taking other medications and supplements. Telling your doctor about every medication and supplement you take is an absolute must, because many over-the-counter medications like aspirin and ibuprofen can decrease the effect of ACE inhibitors and/or lead to water and sodium retention. Some herbs and supplements can interact with ACE inhibitors.
• Contraindications. If you’re pregnant or breastfeeding, have had renal artery stenosis, or have hypersensitivity to the medication, you shouldn’t be taking them. 

Do ACE inhibitors have any side effects?

Yes, like with every medication, some adverse effects might occur. However, they’re not very frequent. You should let your physician know if you have any side effects, and not try to treat them with over-the-counter medications or remedies before you consult your doctor.

The side effects of ACE inhibitors include:

• Dry, consistent cough
• Skin rash (red and itchy skin)
• Nausea
• Metallic taste in your mouth (usually only in the beginning of the therapy)
• Dizziness and lightheadedness (this can happen if your blood pressure drops too low)

When should you seek immediate medical attention?

If you have symptoms of a severe allergic reaction (swelling of the face, tongue, and neck), have trouble breathing, chest pain, feel your heart racing, or if you come up with a fever.

Is there an alternative to ACE inhibitors?

For people who are extra sensitive to this class of medications, a class called ARBs or angiotensin II-receptor blockers can be considered. They act on the same system, but they don’t block angiotensin II from forming. Instead, they block receptors that angiotensin II binds to mediate its effects. 

COVID-19 and ACE inhibitors: Is there a link?

You might have heard that the novel SARS-CoV-2 virus also binds to ACE2, present on the surface in our lungs and in kidneys. Millions of people across the world are taking ACE inhibitors and ARBs for different cardiovascular diseases, and we already know that having a cardiovascular disease has been associated with worse outcomes of COVID-19. 

However, when it comes to treatment with ACEI/ARBs, there is still no conclusive evidence that they’re associated with higher risk or worse outcomes. Some studies are still being conducted, but for now, the WHO says there’s no direct evidence, and that you shouldn’t stop taking your medication. If you still have concerns over it, consult your physician.