PAH Risk Assessment Tools Successfully Predict Survival for 5 Years After Diagnosis

Three common risk assessment tools used for pulmonary arterial hypertension (PAH) successfully predict transplant-free survival up to 5 years after diagnosis, according to a new paper published in Respiration.

The 3 assessments reviewed were the most commonly used scores: the Registry to Evaluate Early and Long-Term PAH Disease Management (REVEAL), the score developed by the Swedish/Comparative Prospective Registry of Newly Initiated Therapies for Pulmonary Hypertension (COMPERA), and the score developed by the French PH Network Registry (FPHR).

“Risk stratification scores provide prediction of mortality risk and allow clinicians to determine [a] patient’s prognosis and treatment approach, and optimize lung transplantation timing,” the authors explained.

REVEAL was initially derived from a cohort of 2716 patients at 54 centers in the United States. It was updated to include all-cause hospitalization within the last 6 months of diagnosis as a new variable and the kidney function variable was revised. The REVEAL score categorizes patients as low-risk with a score of 6 or less with a 12-month mortality risk of 2.6% or less; as intermediate with scores of 7 or 8 with a 12-month mortality risk of 6.2% and 7.0%, respectively; and as high-risk with a score of 9 or greater with a 12-month mortality risk of 10.7% or greater.

FPHR includes 4 low-risk criteria: World Health Organization (WHO)/New York Heart Association (NYHA) Functional Class (FC) I or II; 6-minute walk distance > 440 m; right atrial pressure < 8 mm Hg; and cardiac index ≥ 2.5 L min-1 m-2. Patients with 3 or 4 low-risk criteria have less than 5% 1-year mortality risk, with 1 or 2 low-risk criteria have a 5% to 10% 1-year mortality risk, and those with no low-risk criteria have a greater than 10% 1-year mortality risk.

COMPERA adds 2 additional variables to the FPHR: brain natriuretic peptide (BNP) < 50 ng L−1 or N-terminal pro-BNP < 300 ng L−1 plasma levels and mixed venous oxygen saturation > 65%. The variables are mapped to low-, intermediate-, or high-risk grade, then the mean of the risk grades is summed and divided by the number of available variables. The final number is rounded to the next integer. Patients with a score of 1 are low risk, 2 are intermediate risk, and 3 are high risk.

The researchers collected retrospective data on 50 patients with PAH and categorized their risk at baseline and at 1 year with the assessments. The mean age of the patients was 54.8 years at diagnosis and 68% were female. At baseline, 72% were classified as WHO/NYHA FC III/IV, although this improved at 1 year of follow up to only 38%.

At baseline, 68% were categorized as high risk using REVEAL. However, most patients were classified as low or intermediate risk using COMPERA (94%) and FPHR (80%). “Compared to baseline, the number of low-risk patients increased and high-risk patients decreased according to the 3 scores calculated at 1 year,” the authors found.

For REVEAL and COMPERA, the transplant-free survival at 3 years was better predicted by the scores from 1 year after diagnosis than the scores calculated at baseline. By 5 years of follow-up, this was only true for REVEAL.

“The 5-year prediction was inferior for REVEAL 2.0 compared to COMPERA and FPHR computed at baseline…despite that REVEAL includes more variables and thus would be expected to be more accurate in risk assessment,” the authors explained. They hypothesized that this may be because of the additional variables in REVEAL, which might confound the predictive accuracy after 3 years.

The authors suggested that scores be re-calculated after 6 and/or 12 months as response to treatment could have a major impact. “Further investigation is necessary for the evaluation of potential new variables that could improve the prediction of the 3 risk assessment tools,” they concluded.

Reference

Vraka A, Yerly P, and Aubert J-D. Comparison of risk stratification scores in pulmonary arterial hypertension: a monocentric retrospective study at Lausanne University Hospital. Respiration. Published online January 19, 2022. doi:10.1159/000520886