Treating plaque buildup in coronary arteries, i.e. atherosclerosis, involves a combination of lifestyle changes, medications, and if required, surgical intervention.
Plaque is a mixture of fat, cholesterol, calcium, cellular waste and a clotting protein called fibrin that collects on your artery walls over time.
This mix can accummulate, making these blood vessels narrower or blocked.
This then stops fresh blood from reaching parts of the body, eventually putting the patient at risk of a heart attack, heart failure or stroke.
Procedures such as percutaneous coronary intervention (PCI), coronary artery bypass grafting (CABG) and angioplasty can open narrowed or blocked arteries, and improve blood flow to the heart.
“If it is a soft plaque, we put in a balloon and expand it in the artery, which then crushes the soft material to create a nice lumen (hollow space within the artery walls).
“Then we put a stent in to maintain the lumen to prevent a restenosis (renarrowing of an artery).
“But with severe calcification, it is hard to crack open the artery,” explains consultant cardiologist Datuk Dr Tamil Selvan Muthusamy.
When the plaque’s hard
For severe cases of coronary artery calcification (hardening), treatments such as rotational atherectomy, high-pressure balloon angioplasty and intravascular lithotripsy (IVL) may be used to remove calcifications and improve blood flow to the heart.
However, severe calcification poses multiple challenges due to the technical difficulties in performing PCI, particularly with equipment delivery and stent expansion.
This can lead to poor immediate and long-term outcomes.
IVL is a minimally-invasive catheter-based procedure that uses sonic pressure waves to crack hardened, calcium-heavy plaque in blood vessels.
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Although it is a fantastic breakthrough in treating heavily calcified arteries, IVL has its limitations.
Dr Tamil Selvan explains: “We use a machine to generate ultrasound pulses externally and place the specialised catheter where the blockages are, inducing acoustic waves, which then create pressure to break the calcium.
“But there are limitations in how many ultrasound pulses you can use, i.e. if there are eight pulses, you must break the calcium up in eight pulses.
“The newer devices have 12, which is better.”
The IVL device design is also bulky, making it challenging to insert into the coronary artery.
With big blockages and corresponding small lumens, the catheter might struggle to get in, thus requiring additional techniques.
“Another problem is that it is in ‘one size’, meaning if the artery vessel size is 3mm, the balloon has to be 3mm.
“But if you look at the vessels, they are not the same size from beginning to end.
“They can start at 3.5mm or 4mm, then become 3mm or 2mm, etc.,” he points out.
Breaking new ground
Last year (2025), a team of Malaysian cardiologists led by Dr Tamil Selvan embarked on a study using an advanced, novel version of IVL called the Hertz Contact-IVL System (HC-IVL).
This version was designed to optimise device expansion in calcified coronary artery blockages during a PCI procedure.
Unlike energy-based systems dependent on an external energy generator, the modified lithotripsy device uses a balloon with integrated metallic hemispheres to create focal pressure amplification to break up dense plaques.
HC-IVL creates deep wide cracks in the plaques without damaging surrounding tissue, allowing the artery to expand properly so that stents can be deployed effectively.
Dr Tamil Selvan says: “We are still breaking the calcium, but we do not have an external source – we call it mechanical.
“The catheter has a balloon embedded with tiny hemispheres like stainless steel so when it contacts a hard surface, we apply pressure which gets multiplied and transmitted beyond the vessel wall.
“More importantly, it has much better deliverability because it can go through the entire vessel easily, so we only need to use one balloon for multiple vessels or lengthy lesions.”
The team carefully studied the device’s safety profile.
Since the developer had only conducted small studies across multiple centres in the United States, Dr Tamil Selvan and his colleagues decided to take it up a level and conduct a bigger, local study.
Hence, the Malaysian-IVL Study (MY-IVL) evaluated 102 patients (130 lesions) with notable severe calcified coronary artery disease where traditional energy-based IVL, atherectomy and scoring/cutting balloons had shown significant limitations.
These patients were treated with HC-IVL between April and September 2025 at a private medical centre in Kuala Lumpur.
An independent US lab analysed and adjudicated all the angiographic and intravascular imaging from the patients.
It was found that:
- 96.1% of patients remained free from major adverse cardiac events at 30 days
- 96.3% of patients achieved an angiographic diameter stenosis of more than 30% without intra-procedural complications.
- There were zero HC-IVL device-related procedural complications.
Thrilled with the results, Dr Tamil Selvan applied to the Transcatheter Cardiovascular Therapeutics (TCT) Conference 2025 in San Francisco, US, to present his findings under the “Innovations” category and was accepted.
The TCT is a global scientific meeting and is widely regarded as the leading platform in interventional cardiology, where top experts present breakthrough research that can shape clinical practice worldwide.
The results were well-received and reflected Malaysia’s growing presence in the global cardiovascular research landscape.
“Possibly, we were the first in the world to publish clinical data on HC-IVL.
“This procedure was so successful that it made everyone say: ‘My goodness, you can actually break calcium in a simpler, safer way’.
“The learning curve of HC-IVL is so fast because interventional cardiologists use balloons every day, so they just need several hours of additional training,” says Dr Tamil Selvan.
A one-year follow-up study on the same research participants is in the works.
