The Road Begins to Change
A story of PAH treatment, told from the inside. Three years of medications that eased the load, and a newer therapy that reaches the process causing it.
- Existing oral PAH medications relax the blood vessel walls and reduce the pressure the right ventricle works against, but they do not stop the abnormal cell growth that narrows those vessels in the first place.
- A therapy approved by Health Canada in 2024 works on that growth directly, intercepting the proteins that signal the vessel wall to keep thickening.
- It is given as a small injection under the skin once every three weeks and can be self-administered at home after training from the care team.
- In large clinical trials, walking distance, lung vessel pressure and resistance, BNP, WHO functional class and the risk of clinical worsening all improved at the same time when it was added to standard treatment.
- The new therapy is added alongside existing medications rather than replacing them. Access varies by province as reimbursement pathways continue to be established.
Three Years In
I am the right ventricle. Robert is 64, a retired history teacher from Sudbury, and I have been working in his chest for three years since his diagnosis of pulmonary arterial hypertension. In that time he has been on two medications that have kept things under control well enough for him to live his life, a smaller version of the life he had planned for retirement, but a life. He finishes eighteen holes instead of stopping at nine. He paddles canoe trips that turn around before the good campsites. He plants the vegetable garden in stages with a rest between raised beds. He does not complain about any of this, because the medications have been doing their job, and he knows what the disease looks like without them.
Robert had a list when he retired. Long canoe trips in Killarney Provincial Park. Unhurried time with his grandchildren. A vegetable garden that had been postponed for a decade. Golf, played badly and happily. He was diagnosed the same year he retired, which meant the list and the diagnosis arrived together, and he has been working with both ever since.
Over the past year something has been shifting. His six-minute walk test score, which measures how far a person can walk in six minutes and gives the care team a reliable picture of how the heart and lungs are coping, has come down slightly at the last two check-ups. His brain natriuretic peptide (BNP) level, a protein I release into the blood when my walls are under too much pressure, has edged upward. His overall risk score has moved from low to the next category up. The medications are still working. The disease underneath them has not stopped.
Two oral medications started. Enough control to keep golfing, paddling and gardening, in a smaller version of the life he had planned.
Six-minute walk distance down at the last two check-ups. BNP edging upward. Risk score moves from low to the next category.
A small injection under the skin once every three weeks, self-administered at home, alongside the existing medications rather than replacing them.
Walk distance up by more than 30 metres. BNP down. Estimated lung vessel pressure the lowest since diagnosis. Risk score back to low.
The Problem Underneath the Problem
To understand why this happens, it helps to know what the medications Robert takes actually do, and what they were never designed to do. The blood vessels between me and the lungs have been narrowing for years, their walls thickening with abnormal cell growth that reduces the space I have to push blood through. The two oral medications work by relaxing those vessel walls, opening up the channel, reducing the pressure I push against. They work well. They have given Robert three years of being able to do the things that matter, and that is not a small thing.
What those medications were not built to do is stop the process inside the vessel wall that has been causing the narrowing in the first place. Deep inside the cells that line those vessels, something has been sending a persistent message to keep growing, keep thickening, keep closing inward. The medications work around that message. They ease its effects. But the message itself keeps going, which means the vessel wall keeps responding to it, slowly and quietly, underneath the benefit of treatment.
Think of it as a road. The existing medications made the road wider and easier for me to push blood through, and that has been real and meaningful and has kept Robert going for three years. But the road has been quietly narrowing again underneath, because the thing that was narrowing it was never directly addressed. His BNP level has crept up. His risk score has shifted. His care team looks at these numbers and decides it is time for something different, not because the existing medications have failed, but because the disease underneath them has kept moving and needs to be tackled more directly.
Something That Works Differently
In 2024, Health Canada approved a new therapy for pulmonary arterial hypertension that works on a different part of the problem than anything that came before it. Every previous PAH medication worked on the blood vessels themselves, relaxing their walls, widening them, reducing the pressure I push against. All of them addressed the consequences of what was happening inside the vessel wall without being able to reach the cause. This new therapy goes further. It targets the specific message that has been telling the vessel wall to keep growing. It works by intercepting the proteins that carry that message before they reach the vessel wall, which means the wall stops receiving the instruction to keep thickening. The abnormal growth slows. In some cases it begins to reverse.
The road is not just being made wider. For the first time, the process that was narrowing it is being interrupted at the source.
The therapy is given as a small injection under the skin of the abdomen or thigh, once every three weeks. After the initial training from the care team at the pulmonary hypertension centre, patients can give it to themselves at home. For Robert, who has been making the two-hour drive to the PH centre for check-ups and medication adjustments since his diagnosis, this matters. The new therapy does not mean an extra trip to the clinic every three weeks. He gives himself the injection at home and keeps his regular follow-up schedule at the PH centre as before.
What I notice in the weeks after the new therapy is added is hard to put into words, because I only experience pressure and flow, and what is changing is more subtle than a number on a chart. The resistance is lower, yes, and that alone would be significant. But it feels different from what the existing medications produced. The vessel wall, which has been pressing inward for three years, is beginning to ease. Not dramatically. Gradually, and then more. The road is not just carrying less traffic. It is beginning, slowly and for the first time since this started, to widen on its own.
What the Numbers Show
Three months after the new therapy is added, Robert returns to the PH centre, and the tests that have been tracking his slow decline over the past two years tell a different story. His six-minute walk distance has improved by more than 30 metres, which in PAH terms is a significant gain and one that matches what large clinical trials of this therapy found when it was tested in patients already on standard treatment.
- Six-minute walk distance
- Pressure and resistance in the lung vessels
- Brain natriuretic peptide (BNP) level in the blood
- World Health Organization (WHO) functional class
- Risk of death or serious clinical worsening
All of these things improved at the same time, which makes sense when a therapy is addressing the underlying cause of the disease rather than just one symptom of it. Robert’s BNP has come down. The estimated pressure in his lung vessels on the heart ultrasound is the lowest it has been since his diagnosis. His risk score has moved back to the low category, which is where the care team wants to keep him for as long as possible. The conversation at this appointment feels different from the ones before it, less focused on what is slipping and more on what is possible.
Robert drives himself to this appointment. He has been driving himself for the past two months, which he did not do for most of the previous three years because the fatigue from the two-hour drive and a full morning of tests and the drive back made it unsafe to be behind the wheel. I notice the difference not as something dramatic but as the return of something that had been gone for a while. He can make the trip and still have something left over at the end of it. That leftover energy is new.
What Robert Does With the Room
Six weeks after his follow-up visit, Robert plants the vegetable garden in a single afternoon. He does not plan to do it that way. He starts with the tomatoes, fully intending to rest before moving to the beans the way he has done for three years, and finds when he straightens up from the last tomato cage that the rest does not feel necessary. He does the beans. He does the squash and the zucchini and the two rows of salad greens he has been growing every summer since he was a younger man with less time and more energy. He stands at the edge of the finished garden at the end of the afternoon with soil on his hands and a tiredness that is the good kind, the kind that comes from having done something rather than having tried and fallen short. Anyone who has lived with limited energy will know exactly what that difference feels like.
Two months after that, he drives to Killarney with his son. They put in at a lake Robert has been paddling since his thirties and go out for three hours on the first day, stopping at a campsite he knows well, eating badly and sleeping well the way you only do when you have been outside all day. On the second morning they paddle further than the first. Robert does not tell his son that this is the furthest he has paddled since before his diagnosis, because some things do not need to be said between people who know each other well. I record what I experienced: three hours of sustained paddling, the physical demand of carrying a loaded canoe between lakes, a recovery that came faster and more completely than it has in years. Not dramatic numbers. The arithmetic of a life that has more in it than it did six months ago.
It is worth saying plainly what has not changed. Robert still has pulmonary arterial hypertension. The vessels between me and his lungs are not normal and will not become normal. The new therapy has been approved by Health Canada, but access varies across the country as provinces continue to establish reimbursement pathways, and patients interested in it should speak with their specialist about what is currently available where they live. Robert will keep coming back to the PH centre every few months for the rest of his life. His numbers will be watched. If they shift again his care team will respond. That is what good PAH care looks like today, and it is better than it has ever been.
What Has Changed, and Why It Matters
For the three years before the new therapy was added, I was supported by medications that reduced the pressure I worked against and gave Robert a life that the disease without treatment would not have permitted. Those three years included grandchildren and golf and canoe trips that ended sooner than he would have liked but happened. The existing medications did what they were built to do, and they are still part of his treatment now, working alongside the new therapy rather than being replaced by it.
What the new therapy has added is something the existing ones were never able to offer: a direct effect on the process inside the vessel wall that has been driving the disease. The resistance I push against is lower than it has ever been since Robert’s diagnosis. In clinical trials, every major measure of how serious the disease is improved at the same time when this therapy was added to standard treatment. The risk of the disease getting significantly worse has been reduced substantially. The road is not just easier to travel. For the first time since this started, it is actually getting wider.
I have been working in this chest for sixty-four years. For the first three years after the diagnosis I was compensating alone while the pressure built and nobody had a name for what was happening. For the next three I was kept going by medications that reduced my load without changing what was causing it. Now, for the first time, I am working against a vessel wall that is responding to something that actually addresses the cause. The pressure is the lowest it has been. The garden is planted. The canoe is further down the lake than it was last year.
That is enough to be going on with.
What to Ask About
Pulmonary arterial hypertension is a progressive disease, but the treatment options available today are meaningfully better than they were even five years ago. A new class of therapy approved by Health Canada in 2024 works differently from existing PAH medications by targeting the abnormal cell growth inside the vessel walls rather than only managing the pressure those changes create.
In large clinical trials it improved walking capacity, reduced brain natriuretic peptide (BNP) levels, improved World Health Organization (WHO) functional class, and substantially reduced the risk of death or serious clinical worsening, all at the same time.
It is given as a small injection under the skin once every three weeks and can be self-administered at home after guidance from a healthcare provider. Access varies by province as reimbursement pathways continue to be established across Canada.
If you are already on PAH treatment and your condition has been progressing despite it, talk to your pulmonary hypertension specialist about what options are now available. For more information, visit phacanada.ca.
Frequently Asked Questions
How is the new PAH therapy different from existing medications?
Every previous PAH medication worked on the blood vessels themselves, relaxing their walls and reducing the pressure the right ventricle pushes against. The new therapy targets the message telling the vessel wall to keep growing, intercepting the proteins that carry it before they reach the wall. The abnormal growth slows, and in some cases begins to reverse.
How is the new therapy given?
As a small injection under the skin of the abdomen or thigh, once every three weeks. After initial training from the care team at the pulmonary hypertension centre, patients can give it to themselves at home. It does not require an extra clinic visit every three weeks.
Does the new therapy replace existing PAH medications?
No. It is added alongside them. In Robert’s case the two oral medications he had been taking for three years remained part of his treatment, working together with the new therapy rather than being replaced by it.
What improved in the clinical trials?
Trials run across many countries in hundreds of patients already living with PAH showed improvements in walking distance, in the pressure and resistance in the lung vessels, in BNP levels, in WHO functional class, and a significant reduction in the risk of a serious health event. All of these improved at the same time.
Is the new therapy available everywhere in Canada?
It has been approved by Health Canada, but access varies across the country as provinces continue to establish reimbursement pathways. Patients interested in it should speak with their specialist about what is currently available where they live.
References
- Pivotal clinical trial of the therapy added to background PAH treatment.
- Health Canada approval, 2024.
- WHO functional classification in pulmonary hypertension.
- Part 1I Have Been Working AloneThe early signs, told from inside the right ventricle
- Part 2Your Patient Is Still WaitingWhen to suspect PAH and when to refer
- Part 3The First Time Anyone Measured MeThe tests that confirm the diagnosis
- Part 4The Road Begins to ChangeWhat newer treatment changes, and what it does not
New to this condition? Start with the pulmonary hypertension hub for an overview of the disease, its types and how it is managed.
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Robert is a composite patient created for educational purposes and does not represent a specific individual. This content is intended for education and does not replace clinical judgement or individualized medical advice. Treatment decisions should be made with a pulmonary hypertension specialist.
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