Diving into Pulmonary Hypertension & Its Relation to Other Diseases

The European Society of Cardiology’s 2022 Congress is set to take a deep dive into several cardiac conditions and complications that could impact the diagnostic and treatment landscape. One of these conditions to be highlighted—pulmonary hypertension—may help us better understand how to manage this condition. But how does that change when it’s associated with other conditions?

Advancements in the Diagnosis & Treatment of PAH-CHD

Mortality rates have declined over the past decade for patients born with congenital heart disease (CHD). But among the 1.4 million patients with CHD, pulmonary hypertension occurs in about 10 percent.

PAH associated with CHD, or PAH-CHD, has been linked to reduced survival rates and a worsened quality of life, especially for patients whose PAH-CHD progress to Eisenmenger syndrome, the most severe form of PAH-CHD. But recent advancements in the management of this condition, specifically for our pediatric patients, has reduced the number of patients progressing to Eisenmenger syndrome.

These advancements have shifted our understanding of this disease, and through new discovery platforms, such as computational modeling of flow through the pulmonary vessels and synthetic bioengineering platforms, researchers have found the following about PAH-CHD:

• This disease isn’t just caused by increased pressure and flow in the pulmonary circulation
• Complex genetic and chromosomal abnormalities are the primary cause of PAH with CHD
•  Genome sequencing may allow us to understand this condition better than ever before

There have also been several developments in the treatment of PAH-CHD, one of those being the availability of disease-modifying therapies. An example of this is the treat-to-repair strategy, which involves the use of PAH therapies to bring pulmonary vascular resistance into a range where we can consider the repair of the shunts. However, more long-term data is needed to assess the safety and efficacy of this therapeutic strategy.

Oral therapies have been another novel treatment approach, and while oral therapies targeting the nitric oxide pathway and the endothelin pathway have been available for some time, they’ve often left patients with residual PAH or other symptoms. Researchers are still working to find the most optimal oral therapies for patients with PAH-CHD.

Research is still needed in several areas of treatment for this condition, specifically for the pathogenesis of PAH-CHD. But researchers are also aiming for more clinical testing to be done in this particular population of patients.

Developments in Diagnosis & Therapeutic Challenges for PAH-ILD

Another primary area of clinical research and development is pulmonary hypertension as a result of interstitial lung disease, or PAH-ILD for short. While there has been a lot of debate regarding screening and management for this disease, a recent review from the journal CHEST, details some of the primary challenges involved in the diagnosis and treatment of PH-ILD and may help clinicians better understand how to manage this condition.

One of the challenges clinicians encounter when it comes to screening isn’t about the tools we need to make a diagnosis, but the approach taken when assessing patients for PAH-ILD. And while a physical exam may be unable to predict PH-ILD, a range of common tests may help us predict the likelihood of this condition.

Some of these tests include:

• Assessing diffusing capacity of the lung for carbon monoxide (DLCO) as part of a pulmonary function test (PFT), which can help predict a patient’s PH risk
• Using a six-minute walk test (6MWT) under the umbrella of exercise testing can help us identify reduced heart rate recovery, and in patients with ILD, this can be linked to PH risk
• Thoracic CT scan imaging measuring a pulmonary artery to aorta ratio (PA/A) can predict a mean pulmonary arterial pressure, which can demonstrate an increase risk of mortality due to the PAH in patients with ILD

Traditionally, transthoracic echocardiology is most commonly used to assess the risk of PAH-ILD. This tool measures the right ventricular systolic pressure (RVSP), but clinicians can encounter the challenge of this tool underestimating or overestimating the RVSP. Right heart catheterization continues to be one of the few conclusive tools for diagnosing the assessing the risk of PH-ILD, but researchers recommend using this tool in select cases only.

Given all of these tools, which ones should clinicians select? Researchers recommend a thorough review with PFT, imaging, and data from exercise testing to assess the incidence rate of PAH.

Now while many developments have been made in the diagnostic tools for PAH-ILD, have there been any made for the treatment landscape? In the absence of approved therapies for PH-ILD, clinicians have run into the challenge of trying to select a therapeutic strategy for their patients.

Endothelin receptor antagonist (ERAs) aren’t recommended for PH-ILD treatment, but emerging research has shifted clinicians’ focus to the potential role of pulmonary vasodilators for the treatment of PH-ILD. However, further investigation is needed to understand the full scope of this treatment option.

Based off of clinical studies exploring the treatment landscape for Phil D, clinicians have found that the components of treatment that have been the most effective include a PFT and CT imaging, referrals to ILD centers, and early referral to lung transplantation.

As clinical trial data continues to emerge for patients with all types of pulmonary hypertension, clinicians can continue to find better diagnostic and treatment tools to help care for these patient populations.

References:

https://www.pulmonologyadvisor.com/home/topics/pulmonary-hypertension/pulmonary-arterial-hypertension-associated-with-chd-treatment-gaps/

https://www.pulmonologyadvisor.com/home/topics/pulmonary-hypertension/pulmonary-hypertension-with-ild-diagnostic-and-treatment-challenges/