It’s no longer surprising when someone says he has a stent placed in his coronary artery, or that she has gone for a bypass surgery.
After all, coronary artery disease (CAD), also known as ischaemic heart disease, is the biggest killer in the world, as well as in Malaysia.
According to the Statistics Department, 15% of medically-certified deaths in 2019 were due to CAD.
The casualties were 11,330 (69.4%) males and 4,995 (30.6%) females, with the states of Selangor, Johor and Perak topping the chart.
Like a number of other non-communicable diseases, the patients being struck down by CAD are getting younger.
In 2019, 18% of CAD deaths occurred in the 41-59 age group and 16% in the above-60 age group.
However, the good news is that medical technology is also advancing to help save patients’ lives.
Since the first coronary angioplasty to unclog blocked arteries was performed in 1977, the field of interventional cardiology has progressed in leaps and bounds, giving CAD patients another shot at life.
Angioplasty uses a tiny balloon catheter that is inserted into a blocked blood vessel to help widen it and improve blood flow to the heart.
It’s often combined with the placement of a small wire mesh tube called a stent, which helps prop the artery open, thus decreasing its chance of narrowing again.
Most stents are also coated with medication to help keep the artery open.
These are known as drug-eluting stents.
Angioplasty is also often performed during a heart attack to quickly open a blocked artery and reduce the amount of damage to the heart.
Angiograms are an essential part of an angioplasty.
An angiogram is a procedure that utilises a contrast agent to look at the blood vessels via X-ray.
It shows a two-dimensional silhouette of the interior of the coronary arteries that allows the cardiologist to see how much the vessel has narrowed.
Now, however, there is an imaging tool that allows the doctor to see a cross-section of not only the interior of the blood vessel, but also the layers of the artery wall itself.
This tool, known as intravascular ultrasound (IVUS), uses sound waves (ultrasound) to generate detailed imaging of the heart’s blood vessels.
This makes it possible to evaluate the amount of disease present, how it is distributed, and in some cases, what it is made of.
Explains consultant cardiologist Datuk Dr Tamil Selvan Muthusamy: “It’s a finer version where a camera-like device is attached to the tip of a catheter so that we can further evaluate the coronary arteries.
“With an angiogram, yes, we can tell that the artery is narrowed, but with IVUS, we can also assess the severity and nature of the blockage as we can see the artery inside out.
“Normally, we will balloon and put in a stent in many situations, but if you have IVUS knowledge, your techniques of angioplasty may differ, particularly if you have a severely calcified (hardened) artery.
“Then a normal balloon or stent may not work, and we have to decide what is the most appropriate device to tackle the blockage.”
Improved outlook
In 2018, a three-year study was conducted on 1,448 patients to determine the percentage of patients who had recurring blockages after undergoing a stenting procedure, also known as target vessel failure (TVF).
It was found that only 6.6% of patients who underwent IVUS-guided procedures had TVF.
This was significantly lower than the 10.7% of patients who did not undergo IVUS and had TVF.
Published in the Journal of the American College of Cardiology, the results of the study emphasise IVUS’s ability to help reduce the chances of TVF by almost half.
This is important as a main risk of angioplasty, compared to bypass surgery, is renarrowing of the affected artery.
Thus, the use of IVUS could help improve the long-term results of angioplasty with stent implantation.
Says consultant cardiologist Datuk Dr Rosli Mohd Ali: “With IVUS, doctors can get a clear look at the final stent expansion and reduce the chances of post-procedure complications, thus achieving better long-term outcomes as shown in numerous studies.
“At the same time, we can also see the edges of the stent and if there is any tear in the vessel that may cause a blood clot.
“If this happens, a patient can get a heart attack after the procedure – sometimes within one to two hours.
“In certain areas, it is almost compulsory to use IVUS, e.g. in the left main trunk, which supplies two-thirds of blood to the heart.
“If anything happens there, it can be catastrophic, and sometimes, we can lose a patient there and then.”
Although IVUS technology has been around for more than 20 years, it has only recently made inroads in Malaysia.
Last year, IVUS was used in 8.7% of angioplasties in Malaysia.
In Japan, it was used in 80% of such procedures; in Singapore, 25%; in the United States, 6%; in Europe, 4%; and in India, 3%.
While the long-term outcome is more promising, not all cardiologists are using IVUS.
Cost and experience
It’s probably due to financial issues, Dr Tamil Selvan says, as the overall cost may be 10-15% higher.
In Japan, almost every patient has insurance, so IVUS is widely used.
Dr Rosli opines: “Another reason besides cost is because some cardiologists are not comfortable interpreting what they see.
“When you don’t have the confidence, the chances of picking up the device and using it is probably lower.
“You don’t need special skills, but you need to know how to interpret findings and act on it – this comes with education and experience.
“It does take a bit more time and not all cardiologists have the patience.
“In teaching institutions, the young ones are quick to pick it up, provided they are given the go- ahead by the senior consultants.”
Both consultants have each performed more than 100 IVUS-guided procedures to date.
“Very often, we are faced with patients who return and we see the stents have narrowed – not be- cause of cholesterol plaque, but due to the healing process and scar tissues forming inside.
“In these cases, we prefer to use IVUS.
“We usually find that the stents are underdeployed to start with, so not only are we are treating the scar tissue, but we also have to create enough lumen (space in the artery) so that the renarrowing doesn’t occur,” says Dr Tamil Selvan.
Basically, the concept is: the bigger the lumen, the better.
Dr Rosli elaborates: “Angiographically, you can sort of gauge, but you cannot know what it is like inside the vessel.
“You deploy the stents at a certain point and you think the results will be good, but it may not be because you only see two dimensions, whereas with IVUS, you can see three.
“For me, if the patient comes in with typical symptoms of angina or chest pain due to lack of blood flow to the heart, and he’s got a typical profile – elderly, high cholesterol, diabetic – I will advise an angiogram.
“There are certain patients who say they want other tests instead of an angiogram.
“If the pain is not severe, then it’s okay, but if the symptoms are severe, the blockage is probably significant and they need an angiogram.”
Dr Tamil Selvan adds: “The investigation you do is dependent on the individual.
“If I see an 87-year-old with a typical angina – obviously, the heart is diseased and we try our best to give medications to subside the symptoms.
“We don’t do any procedures (as the patient is elderly) unless the symptoms are really bad, then we take the risk.”
Achieve your targets
How long can one live after stenting?
Says Dr Rosli: “One must remember that treatment via stenting or bypass surgery is not a cure.
“I’ve seen bypasses get blocked again within a couple of months; the same thing with angioplasty.
“What is important is to take care of yourself and address all your risk factors, e.g. diabetes, hypertension, smoking, obesity, etc.
“Be on proper medication, but you must achieve the right target.
“There is no point taking cholesterol medications and the level goes down, but it still doesn’t achieve the target.
“That means the disease will still progress on, so you have to do something to halt this progression.”
When a coronary artery gets blocked again, it doesn’t necessarily mean it is from the previously-treated site.
He continues: “Data shows that 50% can be at a different site, so this tells us the progression of disease is what drives lesions at the same or new sites.
“That’s why it is important for people be on proper treatment and achieve targets consistently.”
The other aspect is the procedure itself – the correct technique must be used.
“You have to look at the blood vessels – if the vessel is small, has lesions or is calcified, then whatever the method we use, the results may not be good,” says Dr Rosli.
The blockages are likely to return, although it can vary from being very quick to years.
The upside, as Dr Rosli adds, is that: “Technology is always expanding and devices are only going to get better.”
Not total freedom
A lot of patients feel that once they have a stent, they’re “free” forever.
“That is wrong!
“It is common for patients to ask if they can stop taking cholesterol tablets once their levels are normal and I always tell them no.
“They’ll ask how long more and I tell them they have to take it until they are 90, then we push them off the cliff!” jokes Dr Tamil Selvan.
Another common question patients ask is if they need a bypass surgery if they have more than three blocked vessels.
“It depends on the location of the narrowing,” he says.
“If I put seven or eight stents and I can get very good results, so be it.
“But if I can only put in two stents and get bad results, then a bypass is best.
“Data has shown that the longer the stents and the more we use, the risk of recurrence is higher.
“So we try to use shorter stents instead of longer ones unless there is a valid reason.”
There are also other devices available in the market that can be utilised.
Dr Rosli says: “There are special drug-coated balloons where the drug goes into the tissue and there is a reduction in the risk of renarrowing.
“This drug is similar to the one placed on the drug-eluting stent.
“If the results are good, we don’t have to stent that area.”
Do note that if you’re diabetic – like one in five Malaysian adults – you’re twice as likely to have CAD as high blood glucose levels can damage blood vessels and nerves that control the heart.
Dr Tamil Selvan stresses that CAD will probably strike at an even younger age group in a decade’s time, so the “fight should begin in schools now”.
“Be aware that CAD is a chronic disease and a burden to the country.
“We need to take care of ourselves for ourselves and for our families,” concludes Dr Rosli.
Reference
