Predicting Heart Attacks

NASHVILLE, TN (American Health  Newswire) -- Every 35 seconds, an American dies of heart disease. If your family has a history of heart attacks or stroke, you are twice as likely to have one yourself. Now, for the first time in medical history, two tests can predict if your genes are putting you at risk.

Three people, one thing in common: heart disease has killed members of their family.

"In the back of my mind, I feel like I'm a little ticking time bomb," Holly Roche, 45 years old, told American Health.

The odds are not in Roche's favor. She knows her DNA puts her at risk. But what she didn't know -- genes change over time and so can her risk of a heart attack.

"When somebody is healthy, you may not have an expression of certain genes, but when you're sick, you may get an increased level of a certain gene," John A. McPherson, M.D., FACC, FAHA, Cardiologist at Vanderbilt Heart and Vascular Institute in Nashville, TN, said.

Dr. McPherson is one of the first doctors in the country to give a one of its kind blood test that reads a person's genomic expression.

Forty-three year old Larissa Jennings has been feeling tightness in her chest. Her mother, father and grandmother all died from heart disease.

"You can see, I'm a fluffy person as my family would say," Larissa Jennings, 43 years old, stated.

"It's very important that we make sure she's not suffering from coronary artery disease," Dr. McPherson added.

The test measures 23 different genes, focusing on the white blood cells. They're called inflammatory cells because they're activated when plaque builds up in the arteries. Measurements under 25 percent: low risk.

Above 50 percent: high risk. Jennings's results: she had an eight percent likelihood of obstructive disease. Roche's risk: low as well. But this test is for folks who feel out of sorts or have chest pains. What about catching heart failure before the signs kick in?

"I do something every day. Walk. Tennis doubles. I'm a kayaker, and I have a single kayak," Edith Donohue, 72 years old, said.

A lifestyle that helps reduce Donohue's risk of heart failure, but that's not enough for her.

Doctor Christopher deFilippi of the University of Maryland School of Medicine and his team studied a blood test to see what it would reveal in blood samples that were taken over time.

"We found, with this test, two-thirds of older adults in the community had detectable levels," Christopher deFilippi, M.D., Associate Professor at the University of Maryland School of

Medicine, explained.

A highly sensitive version of a cardiac test called Troponin measures Troponin T -- a marker for the process of cell death that causes heart failure. As Troponin levels rise in the blood, so does the risk of heart failure symptoms and death from cardiovascular disease over the next 10 to 15 years.

"It's a great sense of relief," Jennings stated.

"Every time I feel a little twinge, extra beat or skipped beat, I don't go, 'oh my gosh,' because I don't think there's anything wrong with me," Roche concluded.

Two discoveries that could someday alert millions of people who are unknowingly at risk.

Higher Cancer Risk After Cardiac Tests

(American Health Newswire) -- Cardiac imaging tests, such as CT scans could be putting heart attack patients at a higher risk of cancer.

According to a new study, exposure to low-dose radiation is associated with an increased risk of cancer. Typically, the amount of radiation that patients are exposed to is so small that it doesn't pose a major health risk, but when there are multiple scans the damage can start to add up.

Patients with known or suspected coronary artery disease, tend to have more frequent exposures to low-dose radiation procedures. In many places, radiation procedures are replacing non-radiation procedures like stress tests on exercise treadmills and echocardiography (a sonogram of the heart).

Between 1996 and 2006 researchers at MUHC and the Jewish General Hospital in Montréal examined 82,861 heart attack patients who had no history of cancer. Seventy-seven percent underwent at least one cardiac procedure that exposed them to low-dose radiation within a year of the attack. Patients who were treated by a cardiologist had higher levels of exposure to radiation compared with those who were treated by a general practitioner. The findings showed about 12,000 incident cancers detected during follow up, and two-thirds of the cancers affected the abdomen and chest areas.

"These results call into question whether our current enthusiasm for imaging and therapeutic procedures after acute myocardial infarction should be tempered. We should at least consider putting into place a system of prospectively documenting the imaging tests and procedures that each patient undergoes and estimating his or her cumulative exposure to low-dose ionizing radiation," the authors were quoted as saying. 

The authors say the best solution may be using procedures with lower or no radiation exposure, especially if there are multiple procedures involved.

 SOURCE: CMAJ, February 7, 2011