Echocardiographic Pulmonary Hypertension in Patients Positive for Myositis-Specific and Myositis-Associated Antibodies

<b>Background:</b> The prevalence of pulmonary hypertension (PH) in patients who are positive for myositis-specific antibody (MSA) and myositis-associated antibody (MAA) remains unclear. <b>Methods:</b> We conducted a retrospective study of patients with an age of 18 years or older diagnosed with myositis interstitial lung disease (ILD) at our university's ILD clinic between 2019 and 2022. Echocardiographic PH was defined by tricuspid regurgitation velocity (TRV) ≥ 2.9 m/s on transthoracic echocardiography (TTE) consistent with intermediate probability of PH using 2022 European Society of Cardiology/European Respiratory Society (ESC/ERS) guidelines. We grouped patients based on low probability of PH vs. intermediate to high probability of PH. We examined 6 min walk test (6MWT) data, pulmonary function tests (PFTs), all-cause mortality, and rate of lung transplantation. We also evaluated patients who were on immunosuppression vs. those not on immunosuppression. <b>Results:</b> The intermediate to high probability of PH group had a higher prevalence of dermato-specific antibodies (14.2% vs. 34.5%, <i>p</i> = 0.048). Specifically, MDA-5 was found to be more prevalent in patients with intermediate to high probability of PH (7.1% vs. 24.1%, <i>p</i> = 0.040). There was no difference in 6MWT parameters between groups (363.2 ± 115.6 m vs. 294.9 ± 147.5 m, <i>p</i> = 0.108). FVC and DLCO were lower in patients with intermediate to high probability of PH (71.3 ± 22.4 L vs. 58.8 ± 16.7 L, <i>p</i> = 0.037; 56.3 ± 21.8 mL/min/mmHg vs. 36.9 ± 15.5 mL/min/mmHg, <i>p</i> = 0.003). The all-cause mortality and rate of lung transplantation was higher in the intermediate to high probability of PH group (5.4% vs. 20.7%, <i>p</i> = 0.041, 0% vs. 6.9%, <i>p</i> = 0.049). There was no difference in all-cause mortality between patients who were on immunosuppression vs. those who were not on immunosuppression in patients with intermediate to high probability of PH (33.3% vs. 7.1%; <i>p</i> = 0.169). <b>Conclusions:</b> Patients with MSA/MAA may have an increased risk of PH with reduced lung function, higher mortality, and greater rate of lung transplantation. Our study further elucidates the growing body of evidence that dermato-specific antibodies, such as MDA-5 are associated with an increased risk of PH. Further research is needed to investigate the role of PH and immunosuppression in these patients.