Prognostic Value of Right Ventricular Septal Longitudinal Strain in Intermediate-Risk Pulmonary Embolism

BACKGROUND: The interventricular septum contributes 30-60% of right ventricular (RV) output. However, few studies have assessed the prognostic value of RV septal strain in pulmonary embolism (PE). We hypothesized that RV septal strain would predict 30-day mortality in patients with intermediate-risk PE. METHODS AND RESULTS: This retrospective cohort study analyzed consecutive patients with intermediate-risk PE admitted to the Penn State Health Milton S. Hershey Medical Center between 2010 and 2018. The primary outcome was 30-day all-cause mortality. RV septal strain was measured within the RV endocardium and was defined as the mean of basal, mid, and apical septal longitudinal strain. Among 251 patients, 31 (12.4%) died within 30 days of PE diagnosis. RV strain analysis was feasible in 230 (91.6%) patients. RV septal strain was significantly lower in those who died and was independently associated with 30-day mortality (P<0.001). Receiver operating characteristic curve analysis indicated 14.4% as the optimal RV septal strain cut-off value (area under the curve 0.816). Kaplan-Meier curves demonstrated that 30-day mortality risk was higher among patients with low (≤14.4%) than high (>14.4%) RV septal strain (hazard ratio 9.29; P<0.001). CONCLUSIONS: RV septal strain is a feasible and reproducible parameter with strong prognostic value in patients with intermediate-risk PE. These findings highlight the central role of the interventricular septum in RV function and risk stratification.