Stable plaque or heart attack plaque? Researcher builds new MEMS sensor to tell which is which

Nov 23, 2009
The experimental setup. The probe seen scans plaque samples taken from rabbits fed a fatty diet (upper left) and can distinguish stable and unstable versions. It could theoretically go into an angiogram catheter. Credit: USC Viterbi School of Engineering

University of Sourthern California biomedical engineer and cardiologist Tzung "John" Hsiai hopes to develop a new tool to help clinicians distinguish cardiac emergencies requiring immediate surgery from chronic problems manageable with drugs and lifestyle change.

Angiograms, images made by catheters inserted into the arteries feeding the heart, offer an inside view of the interior surface ("lumen") of these blood vessels, often revealing deposits of a dangerous fatty substance called plaque.

But plaque comes in different forms. Some are metabolically stable and firmly fixed in the lumen and treatable with diet, exercise and medication. Others are less viscous and likely high risks to dislodge and cause heart attacks. These require immediate primary coronary intervention () or by-pass surgery.

The problem: current angiogram techniques cannot distinguish the types. "Distingishing stable from unstable plaque remains an unmet clinical challenge," said Hsiai, who holds both M.D. and Ph.D. degrees.

He hopes that the new (MEMS) sensor his lab has created can change this situation.

The lower artery in the illustration has a plaque deposit. But is it unstable, requiring immediate surgery, or stable, in which case medication and exercise might be used instead. Current angiogram imaging can't distinguish the two types. Credit: USC Viterbi School of Engineering

The MEMS system uses minute heat perturbations as a proxy for blood flow and detects changes in bulk resistance for plaque characteristics.

The lab has demonstrated that this sensor can make the distinction between stable and unstable plaque in laboratory examinations of specimens of plaque clogged arteries extracted from rabbits fed a special plaque-producing diet

Another configuration of the same sensors can measure the forces on the artery walls produced by blood flows, identifying spots where back currents may be promoting formation.

The next step will be to embed the MEMS sensors into angiogram catheters, and show that they can accurately make the same distinctions, first in animals, then in human subjects.

Every year, approximately one million Americans undergo angiograms, according to the National Institutes of Health. Heart attacks are the leading cause of deaths in the United States, accounting for approximately one-fifth of total annual mortality according to the American Hearth Association.

And "coronary artery disease is rising worldwide because of changes in diet in developing nations, and parallel increases in obesity and diabetes in the West," said Hsiai.

Hsiai's lab recently received a funding in American Recovery and Reinvestment Act (ARRA) funds from the National Institutes of Health to pursue the research.

Source: University of Southern California (news : web)

Explore further: Ultrasound enhancement provides clarity to damaged tendons, ligaments

add to favorites email to friend print save as pdf

Related Stories

New method effective in detecting dangerous coronary plaque

May 29, 2008

A significant number of patients who suffer a heart attack never have any warning signs. For many of these individuals, the source of the problem is noncalcified plaque, a buildup of soft deposits embedded deep within the ...

Two drugs may stabilize plaques in atherosclerosis

Nov 13, 2006

Two drugs that a Wake Forest University School of Medicine research team has been investigating for lupus for several years may stabilize atherosclerotic plaque in the walls of arteries and help avert heart attacks and strokes. ...

Drug may reduce coronary artery plaque

Oct 12, 2008

Research presented at the 20th annual Transcatheter Cardiovascular Therapeutics (TCT) scientific symposium, sponsored by the Cardiovascular Research Foundation (CRF), suggests that olmesartan, a drug commonly used to treat ...

Fat around the heart may increase risk of heart attacks

Jul 30, 2008

When it comes to risk for a heart attack, having excess fat around the heart may be worse than having a high body mass index or a thick waist, according to researchers from Wake Forest University Baptist Medical Center and ...

Recommended for you

A better way to track emerging cell therapies using MRIs

Sep 19, 2014

Cellular therapeutics – using intact cells to treat and cure disease – is a hugely promising new approach in medicine but it is hindered by the inability of doctors and scientists to effectively track the movements, destination ...

User comments : 0