Dear Doctor: I keep reading about stents, and how it turns out they’re no better for blocked arteries than heart meds. How does something like that get decided?

Dear Reader: You’re referring to the findings from a large international study that evaluated various medical interventions for patients with blocked coronary arteries.

Before we get into the study, we should first talk about coronary artery disease. This is a condition in which the vessels that supply the heart muscle with oxygen-rich blood become blocked. A substance called plaque -- which is made up of cholesterol, calcium, fat and other cells -- collects along the inner lining of the arteries and causes them to narrow. This limits the blood flow in the arteries, and, in some cases, can cut it off entirely. When the flow of oxygen-rich blood to the heart slows or stops, the results can range from chest pain, irregular heartbeat and shortness of breath, to heart attack, to an increased risk of stroke. Bits of the hardened plaque can also break free and cause blood clots, which can also limit or stop blood flow.

Coronary artery disease is the most common type of heart disease in the United States. According to the Centers for Disease Control and Prevention, it accounts for more than 370,000 deaths each year. It’s a serious problem, and researchers have spent decades looking for solutions. These include bypass surgery and the use of stent intervention, which were evaluated in the study.

In bypass surgery, a surgeon uses a blood vessel taken from another part of the patient’s body to route the flow of blood around the blocked artery. A less invasive option is the stent, which is a tiny mesh tube implanted into the artery via a long, flexible tube known as a catheter. The surgeon inserts the catheter into an artery in the arm or groin and then, with the help of a special X-ray machine, guides it through the blood vessels until it reaches the desired area. Once in place, the rigid stent physically opens and supports the artery walls, which allows normal blood flow.

The study you referenced, led by Stanford University and New York University, assessed the medical outcomes of more than 5,100 patients living with moderate to severe coronary artery disease. Researchers divided the study participants into two groups. One group underwent bypass surgery or received a stent. Participants in the other group were prescribed heart medication and instructed to make lifestyle changes, including regular exercise, a healthy diet and quitting smoking. Researchers then followed both groups for between 18 months and seven years, and tracked any cardiac events.

At the end of the study, researchers found that the surgical procedures proved more successful than medication alone at alleviating exercise-related chest pain. However, in the long run, they saw no difference between the two groups when it came to major coronary events, such as hospitalizations, heart attacks and death. In these instances, medication and lifestyle were as effective as surgical interventions. Whether these new findings help settle what has long been a fierce and sometimes contentious debate about treating coronary artery disease remains to be seen.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: Our 76-year-old mom is nervous about getting the special Fluzone shot for older people because a neighbor told her it will make her sick. Is that true? What makes flu shots so important?

Dear Reader: Influenza, commonly referred to as the flu, is a seasonal respiratory illness with symptoms similar to those of the common cold. Both illnesses are caused by viruses, but infection with the influenza virus usually results in symptoms that are more severe and longer-lasting than those of a cold. Unlike a cold, which typically comes on gradually, the onset of the flu is often swift. People who get the flu can experience fever, chills, sore throat, cough, lung congestion, body aches and pains, a stuffy and runny nose, and fatigue or exhaustion. Nausea and diarrhea are possible.

Flu season in the United States is concentrated in the fall and winter. Peak activity occurs between December and February. Symptoms show up from one to four days following infection. Depending on the flu strain, as well as the general health of the individual, it can take up to two weeks for the disease to run its course. Most people recover completely. However, at-risk populations with weaker immune systems, such as the elderly, are at increased risk of complications. These can be moderate, such as sinus and ear infections. Severe complications include pneumonia and, more rarely, myocarditis, an inflammation of the heart muscle, or encephalitis, a brain inflammation. In cases where the presence of the influenza virus triggers an extreme inflammatory response, it’s possible for the patient to develop sepsis, a life-threatening infection.

The special flu shot you refer to is called Fluzone High-Dose, a vaccine that contains four times as much antigen as the standard dose. Antigen is the part of the vaccine that causes the body to build up immunity. As we age, our immune response to influenza vaccines declines. The intent of the quadruple dose of influenza antigen is to make up for that reduction in clinical effectiveness. Recent studies have found the high-dose vaccine to be 25% more effective at preventing infection in the elderly. It is also associated with a lower rate of hospitalizations among those who do get the flu. However, it’s also true that side effects to the high-dose vaccine are slightly more frequent than to the standard-dose version.

People getting either type of vaccine may experience side effects including pain, swelling and redness at the injection site, as well as headache, fever, muscle aches and tiredness. Each of these are reported to be mild and temporary, lasting less than a day or two.

Whether your mother overcomes her fear of the high-dose vaccine or opts for the standard-dose variety, we think that the most important thing is for her to get a flu vaccine, no matter which kind, as soon as possible. You should get one, too. In fact, all of our readers should get the flu shot.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I am an 82-year-old woman. When I was in my teens, I did some sleepwalking. A recent occurrence during the night is making me wonder if I have sleepwalked again. What are some of the things that sleepwalkers have been known to do?

Dear Reader: From the time of the ancient Greeks, people have been writing about the mysterious behavior we call sleepwalking. Hippocrates and Aristotle alluded to it in their writings, Shakespeare used it to reveal character in “Macbeth,” and a sleepwalker sets in motion the plot of the novel “Dracula.”

Formally referred to as somnambulism, sleepwalking is one of a larger group of sleep disorders known as parasomnias. During an episode of sleepwalking, the sleeping individual engages in behaviors as though they were awake. These can range from speaking; to getting out of bed and walking around; to completing complex tasks such as dressing, eating, bathing, cooking, rearranging furniture and cleaning the house. In some cases, sleepwalkers engage in violent behavior that puts them -- and their sleep partners -- at risk of injury. One thing the majority of sleepwalkers have in common is a lack of awareness of the experience as it takes place, and no memory of it upon awakening. Many sleepwalkers have discovered their sleepwalking through the discovery of physical evidence of an episode, such as waking up fully dressed or finding the kitchen filled with dirty dishes.

The disorder is estimated to affect from 2% to 15% of the population. It’s more common in children than in adults, and it is believed to have a genetic component. Episodes of sleepwalking, which can last from a few moments to more than an hour, most often occur during the nonrapid eye movement (NREM) stages of sleep. These are the deeper, dreamless stages of the sleep cycle. Studies show that about half of those who sleepwalk do it once a week. Although the disorder has been linked to stress, anxiety, alcohol use and poor-quality sleep, the exact cause is not yet fully understood.

Symptoms of sleepwalking include a glazed or glassy-eyed appearance, not communicating with others despite appearing to be awake, being difficult to awaken while an episode is taking place and feeling confused or disoriented when an episode is interrupted. People who sleepwalk rarely remember anything that took place during an episode. However, the disorder takes a toll on them physically.

Occasional episodes of sleepwalking aren’t considered to be cause for concern. However, if you suspect that you’re experiencing repeated incidents, we think it’s wise to check in with your family doctor. Sleepwalking accounts for the majority of sleep-related injuries, and it can cause drowsiness and exhaustion due to interrupted sleep. The condition can also be a sign of an undiagnosed sleep disorder or other medical condition. There is no known cure for sleepwalking. Your doctor can help you to identify potential triggers and suggest ways to create a safer environment to prevent injury.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)