I Spy for Heart Disease

August 29, 2014 by

Aug. 29, 2014

By Medical Discovery News

Heart in chest

While a shrink ray like the kind used in science fiction is still stuck in the future, miniature devices are not. Tiny devices have been created to perform a variety of tasks, from an implantable telescope to improve vision in those with macular degeneration to the new pacemaker in clinical trials that is about the size of a large vitamin pill. Now, researchers have developed a catheter-based device smaller than the head of a pin that can provide real-time 3D images of the heart, coronary arteries, and other blood vessels. This is an important invention as the casualties of heart disease continue to rise. Statistically, one in four people will have a heart attack. 

Many Americans are at risk for developing coronary artery disease (CAD) due to the buildup of cholesterol and plaque. If there is a rupture or breakage of the plaque, creating a blood clot, that can result in a heart attack with little to no warning. Traditional diagnostic tests such as stress tests and echocardiograms show how much blood is flowing to the heart. If there are regions of the heart that are not getting as much blood as others, it might be a sign of clogged coronary arteries. However, blood flow can also appear to be normal even with plaque buildup.

Currently, there are a variety of methods that provide images of what is going on inside arteries, including magnetic resonance imaging (MRI), multi-detector Computerized Tomography (CT) scans, and injecting an iodine-based contrast agent into arteries through a catheter. But all these look at the inside of the body from the outside, which is why this new device gives an unprecedented way of viewing the heart.

This invention combines ultrasound imaging with computer processors on a single chip only 1.4 millimeters wide. The body’s signals are processed on the chip then transmitted through 13 tiny cables to a computer monitor, so doctors have a visual of the heart and arteries. The prototype took 60 images per second using very little power, therefore generating little heat. This would allow cardiologists to take real-time images of blood vessels in and around the heart to more precisely determine the extent of blockages. These images also have much higher resolution compared to those taken with machines outside the body.

The next step is to conduct studies using the device on animals to determine its safety and efficacy and to develop potential applications of this technology. Eventually, this data will be submitted to the Food and Drug Administration (FDA) to gain permission to perform clinical trials on humans. Extensive testing will be required before the FDA will approve the device for general use. The developers, a group of engineers at the Georgia Institute of Technology, are also working to shrink the device even further to .4 millimeters so it can generate images of even smaller blood vessels.

Having clearer images of blood vessels would allow surgeons to have a more complete understanding of the blockage they are dealing with before they operate. Hopefully, in the future use of this device will prevent heart attacks and save many people’s lives.

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When Drugs Don’t Work

August 2, 2012 by

By Medial Discovery News

July 14, 2012

 

 

Without the liver, many important medications would simply pass through the human body and not produce any effect. The liver is able to metabolize and break down drugs or chemically alter them so that they become active.

But people with certain genetic variations either process drugs more quickly or lack the ability to metabolize specific drugs. Patients who are unaware they possess such a genetic trait could face potentially fatal complications if their lives depend on the very drug their livers can’t process.

This problem comes up in patients who get cardiac stents. Since the 1990s, hundreds of thousands, if not millions, of Americans have had stents put in. It is a metal mesh tube that is inserted into a blocked artery, especially in heart attack victims, to keep the artery open. A drawback is that within months, the artery can close back up as scar tissue grows. To solve this problem, a new stent came on the market in 2008 that slowly releases medication to prevent tissue growth. Yet the enormously popular stent carries a big risk: clot formation. The body tends to respond to the bare metal as a foreign object and cover it with platelets, increasing the risk of a fatal heart attack or stroke.

To prevent this, patients are given blood thinners, such as Plavix (clopidogrel), for at least a year.  Studies have shown the drug greatly decreases a person’s risks for developing clots. However, a rather large percentage of people carry a genetic variation that does not metabolize Plavix, which means the drug won’t work.

Forty to 50 percent of people with Asian ancestry, 30 percent with African ancestry, and 25 percent with European ancestry can carry this genetic variation. Doctors usually do not know until a patient with a stent begins forming blood clots, and genetic testing for the variation takes days. Now a Canadian company, Spartan Biosciences, has developed a bedside gene test capable of detecting this gene variant.

This gene encodes a liver enzyme belonging to a family of enzymes called P450 that is important in processing drugs. Of the eight known variants of this gene, seven encode inactive versions of the enzyme. The new machine can screen patients for these variants in about an hour.

Tests done at hospitals show personnel are capable of using the machine with little training and results are quick. Spartan Biosciences is waiting for regulatory approval of its machine in Europe and America and hopes to have it in hospitals soon. The company will give away the machine but charge about $200 per test.

The company is also exploring other applications for their technology, including determining drug resistance patterns of a bacterial superbug, methicillin-resistant Staphylococcus aureus (MRSA), and hereditary resistance to standard Hepatitis C treatments. This is likely only the beginning of bedside genetic testing. Ultimately, entire human genomes could be sequenced and analyzed next to the patient, helping doctors practice  personalized medicine.

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