Cardiac Involvement and Heart Failure Staging in Patients with Systemic Sclerosis Without Pulmonary Arterial Hypertension.

Background/Objectives: Systemic sclerosis (SSc) is an autoimmune connective tissue disease characterized by fibrosis and vascular damage, significantly increasing the risk of heart failure (HF). Methods: This cross-sectional study included 61 SSc patients (92% female, mean age 63 ± 13 years), excluding those with pulmonary arterial hypertension, referred to a tertiary pulmonary hypertension center. HF stages were classified according to updated guidelines. Clinical, echocardiographic, hemodynamic, and functional capacity data were analyzed in relation to HF stages. Results: A total of 48% of patients had pre-symptomatic HF (5% stage A, 43% stage B), while 38% had symptomatic HF (stage C). Advanced HF stages were significantly associated with older age (p = 0.02) and multiorgan involvement (p = 0.045) but not with SSc subtype or autoantibodies. Structural and functional echocardiographic abnormalities were prevalent (77% and 10%, respectively). Markers of elevated ventricular filling pressure such as left atrial volume (p = 0.011) and E/e' ratio (p = 0.03) correlated with HF severity. Functional impairment was observed with lower 6 min walk test (6MWT) distance (p = 0.017), reduced VO2 peak (p = 0.015), and increased VE/VCO2 slope (p = 0.002). Resting pulmonary artery wedge pressure did not correlate with HF stage (p = 0.93). VE/VCO2 slope and 6MWT were independently associated with HF severity. Conclusions: Preclinical and symptomatic HF are highly prevalent in SSc patients. HF staging was linked to disease severity, age, and cardiovascular risk factors. Functional capacity tests (6MWT and CPET) serve as valuable tools for HF risk stratification. These findings highlight the critical need for comprehensive cardiovascular assessment and targeted management strategies to mitigate HF progression in SSc patients.