A Novel Quantification Method for Ventricular Septal Curvature in Pulmonary Hypertension Associated With Left Heart Disease

BACKGROUD: Non-invasive assessment of pulmonary arterial pressure is critical in managing pulmonary hypertension due to left heart disease (PH-LHD). The curvature of the interventricular septum (IVS) reflects right ventricular pressure overload. We propose a novel echocardiographic metric-interventricular septal eccentric area (ISEA)-to quantify IVS curvature and evaluate its diagnostic value in PH-LHD. METHODS: We retrospectively analyzed patients with PH-LHD confirmed by right heart catheterization (RHC) and individuals with normal pulmonary pressure as controls. ISEA and pulmonary artery systolic pressure (PASP) were measured by echocardiography. Correlations with mean pulmonary arterial pressure (mPAP) and mean pulmonary capillary wedge pressure (mPCWP) were assessed. Logistic regression and receiver operating characteristic (ROC) analyses evaluated the predictive value of ISEA for different mPAP thresholds. RESULTS: ISEA was significantly higher in PH-LHD patients than controls and correlated with mPAP (r = 0.650) and mPCWP (r = 0.544) (both p < 0.01). ISEA values were greater in patients with mPAP ≥35 mmHg than in those with 20-35 mmHg, but not between ≥45 and 35-44 mmHg. HFrEF patients had higher mPAP and ISEA than HFpEF patients. ISEA predicted mPAP >20, ≥35, and ≥45 mmHg with AUCs of 0.817, 0.842, and 0.822, respectively. Combining ISEA with PASP improved diagnostic performance compared to PASP alone. CONCLUSION: ISEA is a promising non-invasive marker for pulmonary pressure in PH-LHD and may enhance the diagnostic accuracy of conventional echocardiographic measures.