Aortic Stenosis: When the Heart's Gateway Narrows

Renee D
May 5
4 min read

Aortic stenosis (AS) is one of the most common and severe valve conditions that affects the heart. You may not have heard of it, but it impacts approximately 29% of individuals over the age of 65. About 9% of individuals over the age of 75 have severe AS. While every valve in the heart plays a vital role in maintaining adequate blood circulation, the aortic valve is especially crucial. It serves as the gatekeeper, ensuring that oxygen-rich blood reaches the entire body.

Before we discuss aortic stenosis, it's important to understand the normal flow of blood through the heart. This foundational knowledge will help you grasp the significance of the aortic valve and the consequences of its compromise. Let's break it down step by step.

When we think of the heart, we can divide it into two halves: the right side and the left side. Each side has an upper chamber and a lower chamber. In between the upper and lower chambers are valves that allow blood to flow through while preventing it from flowing backward.

Let’s take a journey through the heart

The purpose of the heart's chambers is to fill with blood and then pump it out. This process involves both a filling pressure and a pumping pressure, which help ensure that blood flows in the correct direction. Proper function of the cardiac muscles, along with the correct opening and closing of the valves, is essential for this process to occur effectively.

Now, raise your right hand, as that is where we will begin our journey. We will start on the right side of the heart, follow the blood through the heart to the body, and then to the lungs until it ends up back on the right side again. You can think of it as a circuit that is constantly operating; if that circuit is compromised at any point, the outcome can be detrimental.

Deoxygenated blood enters the right atrium through the superior and inferior vena cavae. As the right atrium fills with blood, the tricuspid valve opens. The right atrium then pumps the blood through the tricuspid valve into the right ventricle. Once the blood has passed through, the tricuspid valve closes to prevent it from flowing backward.

As the blood remains deoxygenated, it approaches the pulmonic valve. This valve opens to allow blood to flow through, aided by the pumping action of the right ventricle, and then closes to prevent blood from flowing backward. The term "pulmo" is Latin for "lungs," so when you encounter the words "pulmonic" or "pulmonary," just think of the lungs. From the pulmonic valve, blood moves into the pulmonary artery (also known as the pulmonary trunk) as it moves toward the lungs.

From the pulmonary artery, blood travels to the lungs where it gets oxygenated. Then it returns to the heart via the pulmonary veins. Inside the lungs, a vital process called gas exchange occurs. During this process, the blood releases carbon dioxide and picks up oxygen. The now-oxygenated blood returns to the heart, entering through the left side. It first enters the left atrium, and when the mitral valve opens, the blood is pumped into the left ventricle. The left ventricle then pushes the blood up towards the aortic valve, which serves as the gateway to the rest of the body. When the aortic valve opens, blood enters the aorta, where it travels to all the organs in the body, delivering rich, oxygenated blood.

What happens when your valve doesn’t open fully

The aorta is essential for supplying blood to all the organs throughout your body. When the aortic valve opens, it allows blood to enter the aorta. When it closes, the valve prevents blood from flowing backward into the left ventricle.

So, what happens when the aortic valve cannot open properly?

Aortic stenosis refers to the narrowing of the aortic valve. This narrowing creates an obstruction to the outflow of blood, which prevents the left ventricle from completely emptying. As a result, the amount of blood sent to your organs is compromised.

Causes (Etiology)

In North America and Europe, aortic stenosis is typically caused by the calcification of the valve leaflets, along with the thickening of the left ventricle muscle, known as hypertrophic cardiomyopathy. In contrast, in developing countries, aortic stenosis is more often caused by rheumatic disease, which is often diagnosed during childhood.

Symptoms

Initially, most people don’t notice symptoms. But as the valve narrows and calcium builds up, they may begin to feel shortness of breath, fatigue, dizziness, or even fainting.”So, there is a general activity intolerance. This progression can lead to chest pain, syncope (fainting spells), and eventually heart failure.

Tests

If you're experiencing symptoms, your doctor will perform a test called an echocardiogram, which is similar to an ultrasound but for the heart. This non-invasive test can be repeated every one to two years to monitor the progression of aortic stenosis, especially if the condition is moderate.

Treatment

Treatment may include medication management. If the patient's symptoms are mild and do not interfere with daily activities, the doctor may suggest monitoring the situation without immediate intervention. It is important to weigh the benefits of symptom management and monitoring against any surgical interventions or procedures. Invasive procedures come with inherent risks. Based on the information from your healthcare provider, you and your family will work with your healthcare team to determine the best treatment for you.

Procedures

Surgical valve replacement is performed in the operating room (OR). In contrast, transcatheter aortic valve implantation (TAVI) is conducted in a catheterization lab (Cath lab). It can also be known as transcatheter valve replacement (TAVR). These procedures will be explained in a separate article.

Take away

Aortic stenosis can be life-threatening; however, it is important to monitor your symptoms closely. Being well-informed about treatment options can help you live your best quality of life. Understanding your options and recognizing the symptoms early can help you make confident decisions about your heart health.

Reference:

American Heart Association. (n.d.-a). Aortic valve stenosis. https://www.heart.org/en/health-topics/heart-valve-problems-and-disease/heart-valve-problems-and-causes/problem-aortic-valve-stenosis

Khan, M. A., Hashmi, A., & Rehman, M. U. (2023). Aortic stenosis. In StatPearls. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK557628/

American Heart Association. (n.d.-b). Managing aortic stenosis symptoms. https://www.heart.org/en/health-topics/heart-valve-problems-and-disease/heart-valve-disease-risks-signs-and-symptoms/managing-aortic-stenosis-symptoms

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