Predictors of reduced cardiac index in patients with acute submassive pulmonary embolism

Abstract

Objectives Determine the baseline clinical, laboratory, and echocardiographic values that predict reduced cardiac index (CI) among subjects with acute submassive pulmonary embolism (PE). Background Submassive PE represents a large portion of acute PE population and there is controversy regarding optimal treatment strategies for these patients. There is significant heterogeneity within the submassive PE population and further refinement of risk stratification may aid clinical decision‐making. Methods We identified subjects with normotensive acute PE who underwent echocardiogram and right heart catheterization (RHC) prior to catheter‐directed thrombolysis (CDT). We sought to determine the predictors of reduced CI, defined as CI < 2.2 L min‐1m‐2. Results Thirty‐two subjects met the inclusion criteria and 41% had reduced CI. Baseline variables did not distinguish subjects with reduced versus normal CI. Brain natriuretic peptide (BNP) was significantly different between the reduced versus normal CI groups (BNP 440 vs. 160 pg/ml, p = .004, respectively). Univariate logistic regression identified BNP, right ventricular (RV):left ventricular (LV) diameter ratio, tricuspid annular plane systolic excursion (TAPSE), and right ventricular systolic pressure as predictors of reduced CI. In a multivariate logistic regression model, only TAPSE was an independent predictor of reduced CI. ROC curve analysis identified the following optimal cut points for prediction of reduced CI: BNP > 216 pg/ml, RV:LV ratio > 1.41, or TAPSE <1.6 cm. Conclusions Almost half of subjects with acute submassive PE have reduced CI, despite normal systemic blood pressure. Optimal cut points for BNP, RV:LV ratio, and TAPSE were identified to predict reduced CI among patients with acute PE. These findings may aid in clinical decision‐making and risk stratification of patients with acute submassive PE.

Hemodynamic compromise in pulmonary embolism: “A tale of two ventricles”

“…For the purposes of therapeutic decision‐making, hemodynamically significant PE is categorized as “Submassive” in patients with RV “strain” but intact systolic blood pressure, whereas the term “Massive” PE is reserved to describe those manifesting frank hypotension, the extreme of the compromise spectrum. The authors of the present article 1 should be congratulated for their contribution emphasizing the importance of identifying the presence of low CO in normotensive acute PE patients with RV dysfunction; tha is, those with submassive PE. Observations from this study showed that 41% of such cases showed evidence of low CO by right heart catheterization, which correlated with echocardiographic evidence of RV dysfunction (increased RV/LV ratio of diastolic dimensions and tricuspid annular plane systolic excursion).…”

Risk Stratification and Management of Intermediate-Risk Acute Pulmonary Embolism

“…A CI < 2.2 L/min/m 2 has been associated with increased risk for PE-related mortality [ 29 ]. In small studies, approximately half of patients undergoing endovascular intervention are noted to have reduced CI on hemodynamic assessment despite being normotensive [ 29 , 38 ]. However, this metric was not utilized in the early interventional trials for risk stratification.…”