CAS

By Peter Galvin, MD

Calcific aortic stenosis (CAS) involves progressive narrowing and stiffening of the aortic valve, through which blood flows from the heart to the rest of the body. Aortic stenosis affects 1% to 2% of adults older than 65 years and about 12% of those older than 75 years in the U.S. Worldwide, aortic stenosis causes 100,000 deaths each year. The most important risk factors for aortic stenosis are a bicuspid aortic valve and aortic sclerosis (thickening of the valve leaflets from calcification). A bicuspid aortic valve has only two leaflets (instead of the usual three leaflets) and is present at birth in 1% to 2% of people. Aortic sclerosis progresses to aortic stenosis (narrowing of the valve) at a rate of 2% per year. Risk factors for aortic sclerosis include older age, male sex, high blood pressure, diabetes, high cholesterol, coronary heart disease, chronic kidney disease, and smoking.

Those with mild to moderate CAS usually have no symptoms, and even those with severe CAS can be symptom free for a few years. The most common symptoms of aortic stenosis are decreased exercise tolerance and shortness of breath with physical activity. Those with more severe aortic stenosis may have leg swelling, shortness of breath at rest and while lying flat (orthopnea), and extreme fatigue. Chest pain, lightheadedness, and fainting are less common but may occur with severe disease.

Moderate to severe aortic stenosis often causes a heart murmur, which can be detected with a stethoscope. Echocardiography, an ultrasound of the heart, is the primary test for confirming aortic stenosis and can determine the aortic valve’s structure and function, as well as the severity of the stenosis. Occasionally, additional tests such as heart catheterization, stress testing, or a CT scan of the heart may be required. Because aortic stenosis is a chronic, progressive disease, patients should report new or worsening symptoms to avoid treatment delays. Asymptomatic patients with aortic stenosis should undergo clinical examination and testing at regular intervals between every 6 months to every year or two, depending on their disease severity. Once aortic stenosis has been diagnosed, referral to a cardiologist is usually recommended.

Currently, there are no medications to slow the progression of aortic stenosis. However, management of high blood pressure and smoking cessation can help reduce the risk of more rapid progression of aortic stenosis and decrease the risk of coronary heart disease. Aortic valve replacement (AVR) is recommended for patients who have symptoms due to severe aortic stenosis. There are two main approaches to AVR:

• Surgical AVR (SAVR) involves open-heart surgery with removal of the aortic valve and replacement with a new valve that is mechanical (typically composed of pyrolytic carbon) or tissue (typically derived from the heart of a pig or cow).
• Transcatheter AVR (TAVR) is a less invasive procedure in which a new aortic valve is inserted through a catheter, usually via the groin, and guided through the arterial system to the heart. Once placed, the new valve expands, and the old valve is pushed aside.

Patients with symptomatic severe aortic stenosis who do not undergo AVR have a 50% mortality rate at one year. Those who undergo SAVR or TAVR have survival rates similar to people without CAS. For more information go to www.cardiosmart.org

Please direct questions or comments to editor@rockawaytimes.com