Just what is PAH, what’s its relationship with scleroderma, how do doctors diagnose it and manage it? Dr Aitken set out to provide some answers.
Pulmonary arterial hypertension is a type of high blood pressure. It affects the arteries in your lungs and the right side of your heart.
The right side of the heart is designed to pump at the lower pressures found in the lungs. If the lung arteries and capillaries are constricted, the right side of the heart must pump harder to force blood through. You need good blood flow through the lungs because that’s where your blood picks up oxygen. Inadequate oxygen absorption can cause breathlessness, a build-up of fluid in the legs and abdomen and it strains the heart. There are many types of hypertension. Pulmonary arterial hypertension is less common. Its causes include:
- Left heart disease
- Lung disease
- Clots in the lung arteries
The good news for those with PAH as a result of scleroderma (and those with clots in lung arteries) is that specific treatments are available.
“While pulmonary hypertension, or PH, is reasonably common, PAH, or pulmonary arterial hypertension is relatively uncommon,” Dr Aitken says. It’s a specific concern amongst a sub-group who have scleroderma. There are around 50 PAH cases per million of population. That’s nearing 250 cases in New Zealand. Dr Aitken says there are about 160 cases receiving treatment so around 90 cases present in New Zealand aren’t receiving therapy. Around a third of patients who are being treated have scleroderma as an underlying cause, so it’s relatively common, in an uncommon group.
- Cyanosis (blueness)
Testing for PAH
Investigating whether a patient has PAH ranges from oldfashioned exercise to modern electronics. There’s a 6-minute walk test up and down a room between markers to assess changes in oxygen levels and heart rate, and the level of breathlessness. It’s a good test to repeat a few months after treatment begins, to measure progress.
Other investigations include electrocardiogram (ECG), Echocardiogram (ECHO) and lung function tests. Then there’s CT scans to find if there’s scarring or clots that might contribute to problems.
In the end, there is a test that can definitely confirm the presence of PAH: a cardiac catheter test. Doctors insert a catheter into a leg or arm and feed it right up into the heart chamber. The catheter measures pressure inside the heart’s chambers.
“If someone tells you that you have pulmonary arterial hypertension and you haven’t had this test then we don’t know that you do have it,” he says. “This is the diagnostic tool that’s required.” He says that although it sounds serious to have a catheter wind its way through your leg or arm, into the right side of your heart, you’ll be able to walk away after a couple of hours lie-down. “It’s not a big deal at all.
It’s a relatively non-invasive procedure,” Dr Aitken says. And it specifically identifies whether you would benefit from the medicines available. Early detection seems vital.
Patients in whom PAH is detected and treatment begun, even before they display symptoms, have longer life expectancies than those whose PAH are treated only after PAH symptoms arise.
A 2011 study found that 64% of those whose systemic scleroderma-related PAH had been detected early and treated with relevant medicines, had a survival rate of 64% after 8-years. That compared with 10% survival for those who received treatment only after their symptoms made it clear that they had PAH.
Dr Aitken says the catheter inserted through the right side of the heart gives that early warning and suggests that early screening would be beneficial to people with scleroderma.
In 2013, an international group of medical researchers and doctors studied 460 scleroderma patients, each of whom had had scleroderma for at least 3 years. Their study encompassed 60 countries. Their “gold standard”, Dr Aitken says, was the right-heart catheter study. They were trying to find a standardised way to identify those who should have further study for PAH, without over-investigating and also not missing any.
They were able to identify 70 out of 450 patients at risk of PAH. That’s more than 20% who were detected before showing symptoms. Again, Dr Aitken says a screening programme would be beneficial as the incidence of PAH was greater than thought.
15 years ago, Dr Aitken says general physicians would have said there was little point in trying to detect PAH as there was little or no treatment for it anyway. But that’s no longer true.
Modern treatments change the way people feel and improve their quality of life.
Supportive therapies include physiotherapy and breathing exercises. General, specific exercise and, in some cases, oxygen, all work to mitigate the effects of PAH.
Modern drugs help dilate lung blood vessels, decrease heart strain and improve symptoms. Things are moving on for those with PAH, particularly if it’s detected early.