PO:31:166 | S'/PAPs ratio in systemic sclerosis: a promising non-invasive index for early detection and prognosis of pulmonary hypertension. A step toward more accurate screening?

Marco De Pinto¹, Amelia Spinella¹, Pierluca Macripò², Alessia Laneri¹, Benedetta Bongiovanni¹, Maria Grazia Malandra¹, Martina Orlandi^1-3, Gianluca Pagnoni², Arianna Maini², Rosario Rossi^2-4, Clodoveo Ferri¹, Francesca Coppi^2-3, Dilia Giuggioli^1-3. | ¹Rheumatology Unit, Azienda Ospedaliero-Universitaria Policlinico di Modena, University of Modena and Reggio Emilia, Modena, Italy; ²Cardiology Division, Azienda Ospedaliero-Universitaria Policlinico di Modena, Modena, Italy; ³Department of Medical and Surgical Sciences for Children and Adults, University of Modena and Reggio Emilia, Modena, Italy; ⁴Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy.

Background. Pulmonary hypertension (PH) is a severe and multifactorial complication in systemic sclerosis (SSc), with right ventricular (RV) involvement playing a pivotal prognostic role. Echocardiography remains the cornerstone for PH screening and monitoring. However, traditional indices such as TAPSE are limited by geometric assumptions, angle dependency, and operator variability. The systolic velocity of the tricuspid annulus measured by tissue Doppler imaging (TDI S') has emerged as a more accurate and reproducible parameter. Based on this, the S'/PAPs ratio—reflecting RV-arterial coupling—has been proposed as a valuable non-invasive tool for early detection and risk stratification in SSc-related PH. Nevertheless, clinical data in this specific setting are still scarce.

Materials and Methods. A retrospective/prospective analysis was conducted on 200 SSc patients followed at the Scleroderma Unit of the University Hospital of Modena between 2020 and 2025. Among them, 19 had a confirmed diagnosis of PH based on hemodynamic criteria. Collected data included clinical, echocardiographic, respiratory, serological variables and outcomes. The main objective was to evaluate the diagnostic performance of the S'/PAPs ratio, identifying a reliable cut-off and comparing it with the established TAPSE/PAPs <0.55 threshold. Associations between S'/PAPs and patient characteristics were also explored.

Results. ROC curve analysis identified five S'/PAPs cut-offs (0.328, 0.34, 0.36, 0.38, 0.40). For each, sensitivity, specificity, positive/negative predictive values, accuracy, likelihood ratios (LR positive/LR negative), and Youden index were calculated. The 0.40 cut-off demonstrated the best diagnostic performance, outperforming TAPSE/PAPs <0.55 in sensitivity (89% vs 74%), NPV (98% vs 97%) and LR negative (0.14 vs 0.26). Patients with S'/PAPs <0.40 showed worse clinical and echocardiographic profiles: older age (p=0.001), older age at diagnosis (p=0.038), higher prevalence of limited cutaneous subset (p=0.035), systemic hypertension (p=0.0001), reduced DLCO_Sb (p=0.041), lower 6-minute walk distance (p=0.001), and higher BNP levels (p=0.052). ECG abnormalities were also more frequent (right bundle branch block, p=0.005; atrial fibrillation/SVT, p=0.004), as well as pathognomonic echocardiographic signs of PH. Mortality and cardiovascular events during follow-up were significantly higher in the S'/PAPs <0.40 group (p=0.003).

Conclusions. The S'/PAPs ratio is a simple, reproducible, and sensitive index for non-invasive assessment of RV function and afterload in SSc. A cut-off of 0.40 demonstrated superior diagnostic performance over TAPSE/PAPs, particularly in sensitivity and NPV, making it useful to rule out PH. The prospective analysis is ongoing to confirm the promising role of S’/PAPs ratio in SSc associated PH, in order to improve screening algorithm specificity, sensitivity and NPV and to reduce the number of referrals for right heart catheterization.