The latest European Respiratory Society guidelines on pulmonary hypertension include a major change to the haemodynamic definition of the condition, the TSANZ 2023 ASM has heard.

Guideline co-author Associate Professor Gabor Kovacs presented an outline of the ERS document, which was published last year in collaboration with the European Society of Cardiology (ESC).

Chief among the updates was a reduction in the mean pulmonary arterial pressure (mPAP) for diagnosis, which had been ≥25 mmHg in the previous 2015 guideline, said Professor Kovacs of the Medical University of Graz, Austria.

“Now we can clearly say that pulmonary hypertension can be defined as the mPAP of >20 mmHg,” he said.

Professor Gabor Kovacs

Meanwhile, for pre-capillary pulmonary hypertension, the pulmonary vascular resistance (PVR) threshold had been reduced from three Wood units to two (guidelines linked here).

Accordingly, the mPAP and PVR definitions of post-capillary hypertension had also been altered, while the definition of exercise pulmonary hypertension had also been reintroduced, he said.

These changes had been based on extensive evidence, including a literature review which examined published data on 1200 healthy volunteers and found an average resting mPAP of 14mmHg, with a standard deviation of 3 mmHg.

“This is independent of sex, independent of body position and largely independent of age,” he told the conference.

“So the upper limit of normal is defined as the mean, plus two times the standard deviation – or 20 mmHg.”

Other studies had shown that patients with pre-capillary hypertension under the new definition had a worse prognosis compared with those diagnosed under the old definition, Professor Kovacs said.

He added: “We have therapeutic recommendations that for those patients with non-severe pulmonary hypertension … it is not recommended to give a specific treatment. But in patients with lung disease and severe pulmonary hypertension, an individualised approach is recommended.”

This distinction was made on a threshold of five Wood units, Professor Kovacs said.

And while the section covering treatment algorithms for cardiopulmonary comorbidities was the “most controversial” part of the new guidelines, this was simply a reflection of the current state of the research, he said.

He pointed to data published in 2020 suggesting only 15% of patients fell into the “classic PH” category – mostly young females – whereas there were two other groups who were frequently smokers with comorbidities.

“If you look at treatment effects, the first group really improved upon treatment, whereas there was less improvement in the second and third group,” he said.

“For this 85% of patients, we need to be cautious as we do not really have good data for them.”

He concluded: “So it is very difficult, and those patients who are reacted well from treatment were those who were younger and had better haemodynamic at the same time.”

“Finally… and this is very difficult to put into the guidelines… but each patient is an individual, and you have to sit down with him or her and do shared decision making to find the best treatment for each individual.”