Background/Purpose: Pulmonary arterial hypertension (PAH) is a major clinical challenge in systemic sclerosis (SSc). A new definition for precapillary PH is proposed. Risk stratification is important for disease management, but is not validated in SSc-PAH and is not applied using the proposed criteria. We aimed to assess the performance of current risk stratification tools to estimate the 1- and 3- year mortality and to identify the best risk assessment approach in SSc-PAH.

Methods: We included all patients with newly diagnosed SSc-PAH according to the current and the proposed criteria from the European Scleroderma Trial and Research (EUSTAR) database from 2001 to 2021. The current criteria define PAH as a mean pulmonary arterial pressure (mPAP) ≥25 mmHg, while the proposed criteria use mPAP >20 mmHg; a pulmonary artery wedge pressure ≤15 mmHg, and a pulmonary vascular resistance ≥3 Wood units in the absence of significant interstitial lung disease. We applied four different approaches for risk stratification at time of diagnosis including parameters according to the 2015 ESC/ERS Guidelines (Table).

1: Patients with ≥ 1 high-risk parameter were considered at high risk; ≥ 1 intermediate-risk parameter at intermediate risk, otherwise at low risk
2: Each parameter was graded from 1 to 3 representing low to high risk. The mean of available risk parameters was rounded to the nearest integer to define the risk category
3: Equals Model 2, but the intermediate risk group was divided into intermediate-low and intermediate-high based on the mean score
4: Stratifies patients into four risk categories based on the proportion of low-risk parameters

We used descriptive statistics and performed analysis of 1- and 3- year mortality in patients with a minimum follow-up of 1 and 3 years, respectively.

Results: Of 902 patients who conducted RHC, 271 (30%) were diagnosed with SSc-PAH according to the current criteria and an additional 36 (4%) according to the proposed criteria (Table).

Patients diagnosed according to the proposed criteria were diagnosed at a lower risk level compared with patients with PAH according to the current criteria (Figure 1).

For the current PAH criteria, the 1- and 3-year mortality was 10% and 31%. The models varied in their ability to estimate mortality (Figure 2). Models 1 and 4 either over- or underestimated mortality. Model 2 stratified patients according to the expected 1-year mortality of < 5%, 5-10% and >10% as suggested by the Guidelines. Model 3 segregated the mortality further within the intermediate-risk group.

For the patients who fulfilled the proposed PAH criteria, but not the current criteria, the 1- and 3-year mortality was 0% and 18%. The risk stratification models estimated mortality poorly, possibly due to the small sample size.

Conclusion: Models 2 and 3 seem to be well suited and provide signals for a better risk stratification of patients with newly diagnosed SSc-PAH according to the current criteria, with Model 3 further segregating the mortality in the intermediate-risk group. The patients who fulfilled the proposed PAH criteria, but not the established criteria, were on average diagnosed at a lower risk level, but the 3-year mortality is still high. This may provide guidance for optimized management in clinical practice.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/risk-stratification-of-patients-with-systemic-sclerosis-associated-pulmonary-arterial-hypertension-in-eustar-using-the-current-and-new-proposed-criteria/