by Phyllis Hanlon, Contributing Writer

Adults diagnosed with pulmonary hypertension (PH) are frequently assigned a functional classification during a clinic visit. The functional classification is a way to classify how limited patients are by their disease, and has been used by many physicians and scientists to track disease progress. The scale ranges from functional classification I to IV, and identifies the severity of disease and the urgency for intervention.

However, the WHO functional classification, while useful for adults, was not intended for use in children and infants. A 2016 study noted that since the WHO functional classification does not take into consideration variations in growth and development in children, this classification system is not ideal for medical decision-making or for use in measuring treatment outcomes in young children. Additionally, PH in children is often present in association with conditions other than PH that can affect their symptoms, which makes it harder to assign a functional class.

Emily Morell Balkin, MD, and Roberta L. Keller, MD, were part of a team of University of California, San Francisco researchers who studied children with PH using a child-specific classification system. The Pulmonary Vascular Research Institute (PVRI) Functional Classification of Pulmonary Hypertension in Children (also known as the “Panama Pediatric Functional Class ”) is a modified version of the WHO’s classification system. This system assigns patients to one of five categories (I, II, IIIa, IIIb or IV) that are defined slightly differently for different age groups (0-6 months; 6 months-1 year; 1-2 years; 2-5 years; or 5-16 years). The definition for the Panama Functional Classification specifically takes into account differences in severity of symptoms, limits to physical activity and abnormalities directly related to growth and development considered appropriate for their age group. According to the authors, this system aims “to standardize the assessment of a child’s functional limitations and symptoms,” potentially providing insight into the patient’s quality of life.

The study examined data on 65 infants and children with a diagnosis of PH who were treated at one medical center; 25 (38 percent) had WHO Group 1 PH (PAH, pulmonary arterial hypertension); 1 (2 percent) had PH due left heart disease (WHO Group 2 PH); and 39 (60 percent) had PH as a result of respiratory disease (WHO Group 3 PH).

The main measures the author assessed were the Panama Pediatric Functional Class (FC) at diagnosis, at last visit and any changes noted in FC during follow-up. Dr. Balkin and her colleagues found that the initial FC at diagnosis was not associated with higher mortality and morbidity. However, the last two measures – FC at last visit and changes in FC during follow up – were “strongly associated with mortality and morbidity in children with PH.” They noted that as FC increased, more therapies were used to address PH.

According to the authors, this study did have some limitations. For instance, patient data was retrospectively drawn from just one center so the results might not be applicable to the general population; although they pointed out that the patients were relatively diverse. Also, the study involved a small group of children, which might make the results harder to apply to a larger group.

However, despite these limitations, Dr. Balkin and her colleagues asserted that their findings could be useful as a tool to establish a baseline and evaluate outcomes related to research, providing other studies can duplicate these results in other patients.

Finally, the authors pointed out that “…it will be important to better understand these emerging patient populations of infants and children with PH, so strategies and therapies to improve outcomes can be investigated.”

Each PH patient is different. It is essential that you talk to your own doctor about what treatment options are best for you. For more information on finding a doctor or an accredited care center, visit