Size matters – but not in coronary artery blockages

by Carolyn Thomas   ♥   @HeartSisters

It’s not about your cholesterol numbers, and it’s not even about big fat blockages clogging up your coronary arteries. Did you know that inflammation is likely the culprit in most heart attacks? As cardiologist Dr. John Mandrola neatly describes it:

“Heart disease is about inflammation.  The same mechanisms that cause the throat to swell from an infection, the skin to redden after an insect bite, and a scar to form after a cut are what cause heart problems.”

Studies continue to show demonstrable links between heart disease and other inflammatory conditions.

Most recently this month, these include studies on both idiopathic myopathies (a muscle disease) and ankylosing spondylitis (an inflammatory condition in which some of the vertebrae in the spine fuse together).

An enlightening explanation for inflammation’s role in heart attack comes from this Cardiology Patient Page called Myocardial Infarction: More Complex Than Plumbing, written by Harvard Medical School’s Drs. Kathryn Melamed and Samuel Goldhaber in the journal, Circulation(1): 

Here’s how they describe what’s really happening:

“A myocardial infarction (MI) or heart attack is caused by a sudden blockage in the arteries that supply the heart muscle, known as the coronary arteries. Most of these blockages occur as a result of atherosclerosis, a process in which cholesterol and white blood cells accumulate in the wall of the artery.

“Atherosclerosis leads to the build up of plaque, which is composed of a fibrous cap and a lipid (fatty) core, and grows slowly over years.

“The fibrous cap is composed mostly of a thick, strong material called collagen that functions as a barrier between the blood stream and the lipid core.

“The lipid core is a collection of fats, cholesterol, white blood cells, and proteins that activates clot formation.

“The fibrous cap prevents the lipid core from becoming exposed to the blood. Direct contact between the lipid core and the blood stream triggers a chain reaction that can become fatal: accumulation of platelets, clotting factors, and other cells leads to rapid obstruction of the coronary artery.

“So if the fibrous cap ruptures, sudden blockage happens, leading to an MI.

“The degree of coronary artery blockage or size of the lipid core does not necessarily predict the occurrence of MI or a short lifespan.

“Some people can live long and apparently healthy lives with large plaques in the coronary arteries as long as the fibrous cap remains intact.

“Inflammation is now thought to play a major role in the risk of plaque rupture.

“Inflammation describes the body’s reaction to injury and infection. The inflammatory response includes white blood cells and the signals they send throughout the blood stream and can cause cardiovascular disease. Inflammation thins the fibrous cap and leaves it vulnerable to breakage or injury. Inflammation also interferes with the normal repair process, specifically the synthesis of new collagen, that is necessary to fix a damaged fibrous cap. Once the cap thins too much, it ruptures, and the coronary artery becomes obstructed.  (NOTE from Carolyn: watch this terrific 13-minute tutorial from Kahn Academy for a visual explanation!)

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“Inflammation is increased by diverse stimuli and disease processes. Inflammation may be present in high levels even when there is no injury or infection in the body. Environmental or lifestyle causes of inflammation are important to recognize, because they lend themselves to modification (see the table below).

“Limiting or removing these triggers with lifestyle changes can decrease the risk of developing an MI.

“Health care providers and patients should pay particular attention to:

• cigarette smoking
• alcohol use
• obesity
• hypertension
• diabetes mellitus
• metabolic syndrome (a condition composed of obesity, abnormal lipids, and abnormal glucose metabolism that often leads to diabetes mellitus).

“If these risk factors can be reduced, eliminated, or treated, then the level of inflammation and the risk of MI can be lowered.

Cause of inflammation	Modifiable Action
Cigarette smoking	Tools to quit: -Smoking cessation groups or group therapy -Telephone quit lines (eg. 1-800-QUIT-NOW) -Text message or web-based computer assistance programs (eg. SmokefreeTXT, QuitSTART App, Smokefree.gov) -Over-the-counter nicotine replacement therapy: gum, patch, lozenges, sublingual tablet, inhaler, nasal spray, mouth spray -Prescription medications: bupropion, varenicline -Electronic cigarettes (highly controversial)
Excessive alcohol use	Tools to quit: -Alcoholics Anonymous or other 12 step programs -Behavioral therapy -Detoxification programs -Rehabilitation programs (inpatient or outpatient) -Prescription medications: naltrexone, acamprosate, disulfiram
Obesity	Strategies to lose weight: -Exercise at least 30 minutes per day for 6 days per week -Dietary changes: eg. low-carbohydrate, low-fat, portion control –Weight loss -Advice from a nutritionist or dietitian -Individual or group therapy -Prescription medications -Weight reduction surgery (often called gastric bypass surgery)
Immobility	Strategies to increase daily mobility: -Exercise: at least 30 minutes per day, 6 days per week -Take the stairs instead of the elevator -Attend exercise classes -Walk around a mall if bad weather
Metabolic syndrome or pre-diabetes	Strategies to prevent diabetes mellitus: -Weight loss and diet as described above -Prescription medications: metformin
Hypertension (high blood pressure)	Strategies to reduce blood pressure: –Weight loss and diet as described above, with particular attention to a low salt and high fiber diet and limited alcohol intake –Prescription medications: your primary care physician or cardiologist should select the correct blood pressure-lowering medication among the many available choices
Obstructive sleep apnea	Strategies to combat obstructive sleep apnea: –Weight loss and healthy diet as described above -Avoid sleeping on the back -Avoid alcohol and sedating medications (eg. benzodiazepines, opiates) particularly at night -CPAP or BiPAP machine -Corrective upper airway surgery -Dental appliances
Anxiety or depression	–Psychosocial support from family and friends -Support groups -Individual or group psychotherapy –Prescription medications: see your internist or mental health professional
Autoimmune diseases (eg, rheumatoid arthritis, systemic lupus erythematosus)	-Prescription medications: see your primary care physician or rheumatologist, treatment varies based on disease
Periodontal (gum) disease	–Daily flossing and twice daily teeth brushing -Visit the dentist every 6 months for teeth cleaning -Follow recommendations from your dentist for further oral hygiene
Infection	-Seek medication attention if you are concerned that you have a serious infection that may require antibiotics -Signs of infection often include temperature >100.4°F, heart rate >90 bpm, muscle aches, generalized fatigue

© 2014 American Heart Association – Circulation

(1) Kathryn H. Melamed, MD, Samuel Z. Goldhaber, MD. Myocardial Infarction: More Complex Than Plumbing, Circulation. 2014; 130: e334-e336 doi: 10.1161/CIRCULATIONAHA.114.010614

Q: Were any of these lifestyle causes of inflammation a surprise to you?

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See also:

• Do you know what causes heart disease? (Dr. John Mandrola explains inflammation; visit his excellent blog, too).
  
• Squishing, burning and implanting your heart troubles away
• Are your sleep problems linked to increased heart disease risk?
• What other diagnosis doubles your risk of having a heart attack?
• What your cardiologist (should have) learned last month