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Medical Tests & Procedures Archive

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How do doctors evaluate treatments for heart disease?

Studies of drugs, diets, and devices all come with their own unique set of challenges.

The best way to know if a new medical treatment truly works is with a randomized controlled trial � the "gold standard" of research studies, also known simply as a clinical trial. Volunteers are randomly assigned to receive either the new treatment or the comparison, which may be a placebo (an inactive therapy) or a treatment that's already available.

As the nation's top cause of death, cardiovascular disease has been at the leading edge of evidence generation, says Dr. Robert Yeh, director of the Smith Center for Outcomes Research in Cardiology at Harvard-affiliated Beth Israel Deaconess Medical Center. "We probably have more evidence for cardiovascular treatments than for any other field of medicine," he says. Among the studies with the greatest impact were the clinical trials that heralded new therapies to treat heart attacks. These include clot-dissolving drugs in the 1980s, followed in the 1990s by artery-opening angioplasty procedures, which remain the standard of care today. Stents, the tiny mesh tubes used in these procedures, have also been extensively studied in clinical trials (see "Testing devices: Different dilemmas").

New risk model could better identify people at high risk for pancreatic cancer

Research we're watching

A new tool to identify people who might be at higher risk for pancreatic cancer could help doctors find cases earlier, when they are most treatable. Researchers from the Harvard T.H. Chan School of Public Health created a risk model that did a better job than current models of finding people at high risk for the disease. It takes into account clinical and genetic factors as well as blood levels of biomarkers (substances that could potentially indicate disease). To test the model researchers used data from four large clinical studies. They applied the tool to 500 known pancreatic cancer patients and more than 1,000 people without cancer. The researchers then assessed how well the tool would have predicted the risk of pancreatic cancer. Pancreatic cancer, which is the third leading cause of cancer death in the United States, is challenging to treat because most people already have advanced disease when they are diagnosed. It's hoped that identifying people who are at high risk will eventually allow doctors to screen these individuals to find cancers when they are smaller and more curable.

Image: Raycat/Getty Images

Can high-tech heart scans help prevent heart attacks?

Cardiac CT angiography is gaining ground as a fast, effective way to diagnose coronary artery disease.

If you experience a short-lived squeezing sensation or discomfort in your chest when you exercise or feel stressed, one possible cause is inadequate blood flow to the heart. Known as stable angina, this condition suggests you have heart disease and may be at risk for a heart attack.

Doctors can use a number of different tests to diagnose (or rule out) inadequate blood flow to the heart muscle. The first step is frequently a type of stress test, which checks the heart's electrical activity, muscle function, or blood flow patterns while the heart is under stress from exercise or medication. Stress tests can identify areas of reduced blood flow, which suggest a narrowing in the artery that supplies that part of the heart.

Different types of echocardiography

Ask the doctor

Q. A friend recently had what his doctor called a "3D echocardiogram." How is that different from a standard echocardiogram?

A. All echocardiograms use high-frequency sound waves (ultrasound) to create still and video images of your heart. But there are two different procedures for getting the images and several variations of this common test, which doctors often refer to simply as an echo.

Autoimmunity indicators on the rise among Americans

Research we're watching

An increasing number of Americans have a blood abnormality that indicates autoimmunity, which means their immune system has created antibodies that could work against the body's own cells, according to a study published April 7, 2020, in Arthritis and Rheumatology. Autoimmunity can lead to autoimmune diseases such as rheumatoid arthritis or lupus, although the study authors said they didn't look to see whether the prevalence of diagnosed autoimmune diseases also rose during the same period of time.

The researchers found a rise over two decades in the number of people who had positive antinuclear antibody (ANA) blood tests, a signal of autoimmunity. They used blood samples taken from 14,211 people ages 12 and older, as part of the U.S. National Health and Nutrition Examination Survey. In samples taken in the period 1988 to 1991, ANA prevalence was 11%. It rose slightly to 11.5% for the 1999�2004 time period, and to 15.9% in the 2011�2012 period. Comparing differences in gender, race and age, the largest increases in positive ANA tests occurred in men, non-Hispanic whites, adolescents, and adults ages 50 and older.

Combining two types of biopsies helps diagnose prostate cancer

In the journals

Combining two kinds of biopsies may lead to a more accurate diagnosis of prostate cancer, suggests a study in the March 5, 2020, issue of The New England Journal of Medicine. Researchers from the National Cancer Institute enrolled 2,103 men with prostate abnormalities. Each man had a standard 12-point biopsy and an MRI-targeted biopsy.

With a 12-point biopsy, tissue samples are taken from 12 systematically placed spots on the prostate. An MRI-targeted biopsy uses an MRI image of the prostate to help doctors locate areas where cancer is most highly suspected. Previous research has shown that MRI-targeted biopsies are more accurate than 12-point biopsies. However, even MRIs can miss some tumors.

Should I be screened for hepatitis C?

Ask the doctors

Q. A friend told me that I should be screened for hepatitis C. I'm not in a high-risk group. Is this really necessary?

A. If you're an adult younger than 80 years old, the answer is yes. In March, a government health advisory group, the U.S. Preventive Services Task Force (USPSTF), revised its earlier position and now recommends that all people ages 18 to 79 be screened for this "silent" virus. Prior to this change, the USPSTF recommended only that only high-risk individuals or adults born between the years 1945 and 1965 be screened. Hepatitis C can attack the liver and lead to serious liver damage and liver cancer. The condition is curable if detected. But people often don't consider themselves at risk and are unaware that they are infected, because they typically don't have symptoms.

Are you old enough to give up your screening mammogram?

There's no easy answer to this question. Rather, women should make the decision based on their individual needs.

Most women don't look forward to their routine mammogram, which can be uncomfortable and stressful. You may wonder: Is there an age when can you dispense with this regular chore? 75, 80, 85?

The truth is that experts haven't determined a magic age when women no longer need breast cancer screening � largely because scientific evidence in this area is lacking, says Dr. Kathryn Rexrode, associate professor of medicine at Harvard Medical School and chief of the Division of Women's Health at Brigham and Women's Hospital. But many experts also agree that continuing mammography might not be the right choice beyond age 75. The real question, they say, is what is the right age for you to stop based on your individual needs? To decide, you need to understand both the potential risks and benefits of breast cancer screening.

Blood test might reveal dementia

Research we're watching

Could a single blood test one day enable doctors to diagnose Alzheimer's disease? Researchers writing in the March 2 issue of Nature Medicine say they've made advances in this area. The blood test they developed measures the concentration of pTau181 � a form of the tau protein associated with brain changes in Alzheimer's disease � in the body's blood plasma. They used the test on samples collected from more than 400 people who were part of an ongoing -memory study.

The researchers found that the blood test was able to accurately detect which patients had Alzheimer's, which were healthy, and which had a different type of dementia caused by a neurodegenerative disease. Today, doctors typically diagnose Alzheimer's using a series of tests designed to rule out other causes, but the process is time-consuming and costly. The researchers are now aiming to refine the test further, in hopes that it will someday make it easier to detect Alzheimer's at an early stage, when the disease may be easier to treat.

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