Groundbreaking treatment for heart disease uses lasers to vaporize blockages

[Mar. 3, 2023: Larry Frum, American Institute of Physics]

Atherosclerosis, a buildup of plaque, can lead to heart disease, artery disease, and chronic kidney disease and is traditionally treated by inserting and inflating a balloon to expand the artery. Other treatments based on lasers can remove blockages rather than simply compressing them but are used infrequently, because they have a high risk of complication and low efficacy.

Rohit Singh, of the University of Kansas, and other researchers developed a method that combines a low-power laser with ultrasound to remove arterial plaque safely and efficiently.

High-power laser treatments direct thermal energy to vaporize water in the artery and create a vapor bubble, which expands and collapses to break the plaque. Similarly, the technology, pioneered by Xinmai Yang, doctoral advisor for the team, uses a low-power nanosecond pulsed laser to produce microbubbles. The addition of irradiation from ultrasound causes the microbubbles to expand, collapse, and disrupt the plaque.

"In conventional laser angioplasty, a high laser power is required for the entire cavitation process, whereas in our technology, a lower laser power is only required for initiating the cavitation process," said Singh. "Overall, the combination of ultrasound and laser reduces the need for laser power and improves the efficiency of atherosclerotic plaque removal."

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Because it destroys rather than compresses the plaque, the combination technique will have a lower restenosis rate, or re-narrowing of the artery, compared to balloon angioplasty or stenting. The control provided by the ultrasound and the low-power laser will lower the risk of dissection and perforation in arteries.

The team performed ex vivo experiments on carotid artery plaque samples and pork belly samples, and they are currently planning to perform in vivo experiments. Both the laser and ultrasound techniques are commonly used by clinicians and should be easy to teach and implement following the in vivo studies.

Combining low-power lasers and ultrasound techniques is not limited to atherosclerosis treatments. Singh and collaborators are also using the methodology for photo-mediated ultrasound therapy and ultrasound-assisted endovascular laser thrombolysis. The former can be used to remove abnormal microvessels in the eye to prevent blindness, while the latter can dissolve blood clots in veins.

Heart disease symptoms depend on the type of heart disease.

Coronary artery disease is a common heart condition that affects the major blood vessels that supply the heart muscle. Cholesterol deposits (plaques) in the heart arteries are usually the cause of coronary artery disease. The buildup of these plaques is called atherosclerosis (ath-ur-o-skluh-ROE-sis). Atherosclerosis reduces blood flow to the heart and other parts of the body. It can lead to a heart attack, chest pain (angina) or stroke.

Coronary artery disease symptoms may be different for men and women. For instance, men are more likely to have chest pain. Women are more likely to have other symptoms along with chest discomfort, such as shortness of breath, nausea and extreme fatigue.

Symptoms of coronary artery disease can include:

The heart may beat too quickly, too slowly or irregularly. Heart arrhythmia symptoms can include:

Serious congenital heart defects usually are noticed soon after birth. Congenital heart defect symptoms in children could include:

Less-serious congenital heart defects are often not diagnosed until later in childhood or during adulthood. Symptoms of congenital heart defects that usually aren't immediately life-threatening include:

Early stages of cardiomyopathy may not cause noticeable symptoms. As the condition worsens, symptoms may include:

The heart has four valves — the aortic, mitral, pulmonary and tricuspid valves. They open and close to move blood through the heart. Many things can damage the heart valves. A heart valve may become narrowed (stenosis), leaky (regurgitation or insufficiency) or close improperly (prolapse).

Valvular heart disease is also called heart valve disease. Depending on which valve isn't working properly, heart valve disease symptoms generally include:

Endocarditis is an infection that affects the heart valves and inner lining of the heart chambers and heart valves (endocardium). Endocarditis symptoms can include:

You might not be diagnosed with coronary artery disease until you have a heart attack, angina, stroke or heart failure. It's important to watch for heart symptoms and discuss concerns with your health care provider. Heart (cardiovascular) disease can sometimes be found early with regular health checkups.

Note: Materials provided above by American Institute of Physics. Content may be edited for style and length.

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