Fixing that leaky heart valve

The replacement valve (in cream) is made up of bovine pericardium or heart membrane, and supported by a nitinol frame. — Photos: OrbusNeich P&F

It's now possible to manage a severe leaky right heart valve, or what is medically termed as tricuspid regurgitation, without having open heart surgery.

This non-invasive treatment utilises a delivery system that deploys two dry tissue valves supported by a metal alloy frame, called the TricValve Transcatheter Bicaval Valves.

This bioprosthesis is inserted into the body and placed in the superior and inferior vena cava in a procedure similar to a coronary angiogram, i.e. via a catheter inserted in the right groin.

The vena cava are the veins through which deoxygenated blood from the rest of the body enters into the upper right heart chamber (atrium) on its way to the lungs to get resupplied with oxygen.

The superior vena cava carries blood from your head, neck, upper chest and arms, while the inferior vena cava carries blood from the rest of the body below that.

While this delivery system does not disturb the native leaky tricuspid valve, the two valves deployed in the vena cava effectively help to replace its function and reduce the symptoms of heart failure that result from severe tricuspid regurgitation.

As it is a minimally-invasive procedure, patient recovery is also faster, compared to an open heart surgery.

First in Asia

The National Heart Institute (IJN) became Asia’s first hospital to perform this procedure in May (2021).The dual-valve system is implanted in the superior and inferior vena cava in order to prevent further blood backflow.The dual-valve system is implanted in the superior and inferior vena cava in order to prevent further blood backflow.

The inaugural patient was a 67-year-old woman who had developed symptoms of heart failure and was deemed too high-risk to go under the knife.

She had a long history of hypertension (high blood pressure), and atrial fibrillation or irregular heartbeat.

Says consultant cardiologist Datuk Dr Azmee Mohd Ghazi, “We didn’t have the technology when she was first referred to us a year ago with some degree of heart failure.

“She was deemed unsuitable for surgery and was treated conservatively.

“When this TricValve came about in December (2020), we offered it to her and she agreed (and) she’s doing really well.”

He explains that they judge this by looking at the patient’s quality of life and her improvements in doing daily tasks and activities.

“She requires fewer diuretics (medicines to rid the body of sodium and water) and is able to do more things, which corresponds to some degree of improvement in the right ventricle,” he says.

“However, three months is still too early to see improvements with regards to cardiac size, so we have to wait a little longer (to see that).”

Incomplete closure

The heart valves control blood flow through the heart, ensuring that it all flows in the proper pathway throughout the heart.

When a valve doesn’t close properly, it is considered “leaky”, resulting in some blood flowing backwards instead.

In tricuspid regurgitation, the valve between the two right heart chambers (right atrium and right ventricle) – known as the tricuspid valve – has become leaky, allowing blood to flow back into the heart’s right atrium.

This results in symptoms like fatigue, chest tightness, shortness of breath, reduced exercise tolerance (i.e. decreased ability to exercise), inability to perform daily activities, swelling of the abdomen and/or leg, and discomfort or pulsing in the neck.

Tricuspid regurgitation can be caused by a number of conditions, including:

  • Abnormal enlargement of the right ventricle
  • Heart failure
  • Pulmonary hypertension (high blood pressure in the lung arteries)
  • Cardiomyopathy (disease of the heart muscles)

While there is no local data on the number of patients with tricuspid regurgitation, based on the American figure of 1.6 million patients with the condition, it is estimated that there are 150,000 cases in Malaysia that require treatment.

The disease is categorised from stages one to five.

In severe sufferers who are unsuited for surgery, the outcome is poor, with a mean survival of 2.2 years from the time of diagnosis.

Dr Azmee, who is IJN’s clinical director of heart failure and heart transplant, says: “In IJN, we see many patients with this disease who have been referred to us for further management.

“When we do the assessment, we find that a lot of patients who have tricuspid regurgitation also have other diseases, e.g. coexisting mitral regurgitation in the left heart valve.

“Up to 35% of patients will require some sort of intervention, such as medical, surgical or non-surgical (percutaneous) therapy.”

In the past, a common surgical option was an annuloplasty, a procedure that tightens the annulus – a ring-like structure – around the valve in the heart.

Unfortunately, patients with a severely dilated tricuspid annulus, a pacemaker or other underlying conditions, are unsuitable for such a procedure.

“For such cases, we can now offer this TricValve treatment to help more patients alleviate their symptoms, improve their quality of life, walk a longer distance and reduce mortality,” he says.

Strict evaluation

The valves come in different sizes and are shaped to fit the entry points of the superior (left) and inferior vena cava respectively into the right atrium.The valves come in different sizes and are shaped to fit the entry points of the superior (left) and inferior vena cava respectively into the right atrium.

To date, this new procedure has been carried out on more than 100 patients worldwide.

According to senior consultant cardiologist and IJN Cardiology Department head Dr Shaiful Azmi Yahaya, the selection criteria for patients is pretty strict.

“All tricuspid regurgitation patients have to undergo extensive evaluation, assessment and investigation, and we discuss with experts around the world before we decide if they are suited for this method.

“And because it is percutaneous, we can reposition the valves before we do the final implantation.

“These patients are high-risk ones, so there might be complications such as blood loss, bleeding at the groin, etc, but we have a whole team of experts to back us up,” he explains.

The dry tissue valves come in different sizes and are made from bovine tissue, which does not disintegrate easily.

The valves are supported by a nitinol frame – a metal alloy of nickel and titanium, which has unique properties that allow it to expand to its original shape within the vena cava after being compressed and placed on the delivery system.

“When we open the packaging, we flush the device to hydrate it before implanting it in the human body.

“It’s already treated with anti-calcification agents, so it is durable and the risk of contamination is low,” Dr Shaiful says.

The procedure is performed under local anaesthesia and takes around 30 minutes, although in the first case, it took the team more than an hour.

He says, “Technically, the patient can go home the next day, but for the first few patients, we would rather keep them longer as we’re watchful for any complications that could occur.

“Such patients are usually elderly or on new drugs, and if they are not well informed, they might miss certain signs and symptoms.

“Once we’ve done more than 100 patients, it could become a daycare procedure.

“However, the one ‘side effect’ is that it is expensive.”

The device costs more than RM100,000, although Dr Azmee points out that this is comparable to devices used in other percutaneous procedures, such as transcatheter aortic valve implantation (Tavi), where a faulty aortic valve can be replaced via a similar procedure.

“These valves do not need to be changed regularly, just like other tissue valves such as the Tavi that can last 10 years.

“Even if the patient outlives the valve, we can always go in and change it,” says Dr Shaiful.

The availability of this new procedure at IJN is also a boon for the country’s medical tourism.

“When you have a breakthrough treatment, it will definitely have a positive impact on medical tourism.

“We have a lot of international patients coming in for specific treatments, but the selection process for this TricValve procedure is not easy as we have to first ensure that they are suitable,” says Dr Azmee.

Adds Dr Shaiful: “When we first did Tavi in 2009, many overseas patients from Indonesia, Vietnam, Pakistan, etc. came here to seek treatment.

“Since we are the first centre in Asia to perform this TricValve procedure, we expect the same thing to happen once borders are open and the Covid-19 situation is better.”

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