Late Breaking Abstract - A risk score including parenchymal lung disease improves risk stratification in Group 3 Pulmonary Hypertension

There is limited data on risk stratification in Group 3 pulmonary hypertension and no risk scores including a lung parenchymal assessment. Between 2007-19, 205 patients were identified from the ASPIRE registry. CT emphysema and fibrosis severity was quantified by a validated AI model and graded by radiologists. COMPERA methodology was used to create a risk score. Variables identified from multivariable Cox regression analysis were scored as 1,2,3 for low, medium and high risk, with rounded mean score to assign overall risk. Age (Hazard Ratio, HR, 1.02, p=0.039), AI quantified percentage of lung fibrosis (HR 1.01,p=0.030), PVR (HR 1.14, p<0.001), and DLCO (HR 0.98 p=0.017) were significant multivariable predictors in the derivation cohort. Risk score thresholds for low, medium and high risk for age: <60yrs, 60-70yrs, >70yrs for DLco: >30%, 20-30%, <20%, for PVR <4WU, 4-7WU, >7WU and for CT fibrosis: <3%, 3-7%, >7% or radiologist graded: none/mild, moderate, severe. The risk score (including parenchymal AI (Figure) or radiologist scored) demonstrated significantly different mortality rates in the three risk strata in both derivation (p<0.01) and test (p<0.01) cohorts. In the test cohort 1-year survival rates (AI) were 88% in the low, (n=8), 77% in the medium (n=56), and 40% in the high-risk (n=10) group. A multiparameter risk score including an assessment of lung parenchymal abnormalities can be used to risk stratify patients with Group 3 PH. This may also aid stratification of patients for clinical trials.