How Does Atherosclerosis Relate to High Blood Pressure?
Atherosclerosis is plaque buildup in the arteries. When it occurs in the arteries that supply blood to the heart, doctors call it coronary artery disease (CAD).
Although high blood pressure is common, it's not harmless. High blood pressure can lead to CAD because it adds force to the artery walls. Over time, this can damage these blood vessels and lead to more plaque buildup. The narrowed artery limits or blocks the flow of blood to the heart muscle, which means it might not get enough oxygen.
In time, this may cause chest pain (angina). Plaque can also break off or damage a blood vessel, possibly leading to a heart attack or stroke. Blood pressure higher than 130/80 is seen in:
- 69% of people who have their first heart attack
- 77% of people who have their first stroke
- 74% of people who have congestive heart failure
High blood pressure alone increases the risk for atherosclerosis, but it's especially dangerous if you smoke or you have diabetes or unhealthy cholesterol levels.
When the heart beats, it pushes blood through the arteries in your entire body. Higher blood pressures mean that with each beat, arteries throughout the body swell and stretch more than they would normally. This stretching can injure the endothelium, the delicate lining of all arteries, causing arteries to become stiffer over time.
Healthy endothelium actively works to prevent atherosclerosis from developing. Injured endothelium, on the other hand, allows more "bad" LDL cholesterol and white blood cells to enter the lining of the artery. The cholesterol and cells build up in the artery wall, eventually forming the plaque of atherosclerosis.
High Blood Pressure Basics
Blood pressure is the pressure inside the arteries. It's reported in two numbers, for example, "125 over 80." What do these numbers mean?
- The top number is the systolic blood pressure. This is the peak pressure, when the heart pumps and expands the arteries.
- The bottom number is the diastolic blood pressure. When the heart relaxes, the pressure in the arteries falls to this value.
Normal blood pressure is less than 120 over less than 80. Treatment is recommended for blood pressure above 130 over 80 for most people. Treatment may be considered at lower levels, depending on other medical conditions you may have.
What Are the Symptoms of Atherosclerosis?
In the early stages, you typically don’t have symptoms. Once coronary arteries start to seriously restrict blood flow to the heart, you may feel chest pain (angina) because not enough blood is reaching your heart, especially when you exert yourself or you feel angry or stressed.
It is important to know that symptoms of atherosclerosis depend on which arteries are affected and how much blood flow is blocked. Some of the common symptoms other than chest pain include:
- Cold sweats
- Extreme tiredness
- Heart palpitations
- Shortness of breath
- Problems with thinking and memory
- Weakness or numbness
- Severe pain following meals
What Are the Complications of Atherosclerosis?
- Heart attack
- Peripheral arterial disease
- Erectile dysfunction
- Kidney disease
- Chest pain (angina)
- Pain in the legs (claudication)
- Vascular dementia
What Is a Heart Attack?
A heart attack is a sudden loss of blood flow to the heart muscle. It usually occurs when plaque deposits from atherosclerosis break open and cause a blood clot that clogs an already narrowed coronary artery and so limits or blocks blood flow.
Without enough oxygen, part of the heart muscle is injured and sometimes permanently damaged.
How Is Atherosclerosis Diagnosed?
Doctors often don’t diagnose atherosclerosis until a person complains of chest pain. At this point, the doctor may conduct tests to evaluate your risk for heart disease. These tests include:
- EKG: It uses painless electrodes on your arms, legs, and chest to measure your heart’s rate, rhythm, and electrical activity. It may show if you've had a heart attack in the past or are having one now. It can also show any strain or thickening of the heart muscle.
- Exercise stress test: During this test, a medical team takes EKG and blood pressure readings as you exercise on a stationary bicycle or treadmill. The test has limitations because only serious narrowing of arteries typically shows up as abnormal on the test. Although the test is useful and means you likely don’t yet have serious atherosclerosis, you could still have growing plaque buildup in your arteries.
- Cardiac catheterization: Here, your doctor inserts a small flexible tube (catheter) into an artery, typically in the groin, arm, or neck and guides it through to the heart. They then inject dye to watch which way it flows. This helps your medical team find and measure any blockages in your heart. Sometimes, they can even open up any blockages by expanding a small balloon to push plaque against the artery wall (angioplasty) or placing a tiny metal tube, or “stent,” to keep the blood vessel open.
- Echocardiogram: This test uses ultrasound waves to provide pictures of the heart's valves and chambers. It tells your doctor about chamber size, heart wall thickness, blood flow, and more. Because it’s so easy and noninvasive, the echocardiogram is often used as the first test after EKG to look for heart problems. However, it does have some limitations. For example, it can’t directly detect blockages or plaque buildup in the coronary arteries.
- Carotid ultrasound: This test uses ultrasound waves to provide pictures of blood flow in the arteries of the neck. Because atherosclerosis affects arteries in general, detecting blockages in the neck arteries suggests that it is highly likely that blockages are present in other parts of the circulatory system (including the coronary arteries).
- CT scan: Here, a computer uses X-rays to make a cross-wise image of the heart. This can tell doctors the likely amount of calcium in coronary arteries, which is an indication of underlying atherosclerosis. Some more advanced CT scanners give more detailed pictures of coronary arteries.
- Magnetic resonance arteriography: This test uses a magnetic field and pulses of radio waves to create images of blood vessels and show where they may be blocked.
What Is the Treatment of Atherosclerosis?
Treating high blood pressure can offer dramatic protection against atherosclerosis. Much of the decline in the death rate from heart attacks and strokes is due to improved treatment of high blood pressure over the past 50 years.
For example, one large study found that a 10-point reduction in systolic blood pressure (the top number) lowered the risk of major cardiovascular disease events by 20%, coronary heart disease by 17%, stroke by 27%, heart failure by 28%, and death from all causes by 13%.
Another study found that for each 5-point reduction in systolic blood pressure, the risk of developing cardiovascular events fell by 10%.
Exercise and a low-salt diet that is high in fruits, vegetables, and whole grains will reduce blood pressure by a moderate amount. Keeping a healthy weight can also help. (Ask your doctor about the right weight for you.)
In many cases, your doctor will suggest medication to help control your high blood pressure. In fact, your doctor may prescribe drugs to reduce both your high blood pressure and the risk of atherosclerosis.
High blood pressure drugs include diuretics, beta-blockers, calcium channel blockers, angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers, and alpha-blockers.
Treatment of atherosclerosis typically starts with changes in diet and exercise habits, along with other possible lifestyle changes such as quitting smoking. Your doctor might also prescribe medications, such as statins, to help reduce blood cholesterol levels.
Other treatments may include angioplasty and stenting for severe blockages.
In some cases, your doctor may suggest open heart (bypass) surgery.