Relationship Between Echocardiographic Parameters and The Systemic Immune-Inflammation Index in Patients With Pulmonary Arterial Hypertension

Background: Pulmonary arterial hypertension (PAH) is a chronic disease with high morbidity and mortality.The diagnosis of PAH is mainly made based on echocardiographic parameters and natriuretic peptide levels.However, given the low incidence of PAH worldwide, the diagnosis of PAH can be challenging.Objectives: To evaluate the relationship between systemic immune-inflammation (SII) index and PAH.Methods: This was a retrospective, cross-sectional study of 110 patients (43 PAH patients and 67 controls).The SII index was compared between the PAH and control groups.A probability(p) <0.05 were deemed to indicate statistical significance.Results: The findings of this study indicated that SII index was significantly higher in the PAH group than in the control group (1054.15±439.99 vs. 506.7±180.55,p<0.001).The correlation analysis between SII index and echocardiographic parameters revealed that SII index was moderately correlated with right ventricular fractional area change (FAC) (r:-0.567,p<0.001),systolic pulmonary artery pressure (sPAP) (r:0.593,p<0.001), and tricuspid regurgitation velocity (TRV) (r:0.662,p<0.001).Additionally, the SII index was strongly correlated with right atrial (RA) area (r:0.822,p<0.001),pulmonary artery (PA) diameter (r:0.819,p<0.001), left atrium (LA) diameter (r:0.937,p<0.001),inferior vena cava diameter (r:0.869,p<0.001),tricuspid annular plane systolic excursion (TAPSE) (r:-0.902,p<0.001),TAPSE/sPAP (r:-0.831,p<0.001).In addition, the SII index significantly increased as patients' functional capacity (FC) decreased.Conclusion: The SII index is as a simple, inexpensive, noninvasive and easily accessible biochemical parameter that may be useful in the diagnosis and follow-up of PAH patients, especially in centers where echocardiography (ECHO) is not available.