Right Ventricular Free Wall Strain to Predict Clinical Outcomes in Acute Pulmonary Embolism

Background Submassive (intermediate risk) pulmonary embolism (PE) presents with heterogenous clinical outcomes. Critical management decisions are unclear and improved prognostication is needed. Right ventricular free wall longitudinal strain (RV FWS) is an echocardiographic finding that reflects the pathophysiologic changes in PE and therefore should provide prognostic value. Methods A retrospective cohort study was performed by reviewing the medical records of patients followed by the hospital pulmonary embolism response team (PERT). The primary outcome was in-hospital mortality or hemodynamic instability. Traditional qualitative and quantitative markers of RV function including tricuspid annular plane systolic excursion and velocity (TAPSE and S’) were collected for comparison to RV FWS. A total of 84 patients were included in the final cohort. Logistical regression analysis was performed to assess the primary outcome association with RV FWS, TAPSE, and S’. Multivariate logistic regression was performed adjusting for age, gender, and baseline medical comorbidities. Receiver operating characteristic (ROC) curves and Empiric cumulative distribution function (ECDF) plots were created for all three echocardiographic variables to assess diagnostic performance. Results The primary outcome occurred in 45.7% (n=38) and death occurred in 11.9% (n=10). RV FWS was associated with increased risk of the primary outcome (adjusted OR = 19.3; p=0.0003). RV FWS demonstrated good predictive performance with an area under the curve (AUC) of 70.7%. Significant inverse correlation was noted between the primary outcome and RV FWS when using empiric cumulative distribution function (ECDF). TAPSE additionally demonstrated positive predictive performance, albeit lower than RV FWS. Qualitative assessment of the RV as well as S’ did not demonstrate statistically significant association with primary outcome. Conclusions In this retrospective cohort study of patients with primarily submassive PE, RV FWS demonstrated good predictive performance in terms of death or hemodynamic instability. Further data is needed to validate these findings in a larger population.