Echocardiographic predictors of mortality in intermediate-risk pulmonary embolism

Abstract

Data regarding further risk stratification of intermediate-risk pulmonary embolism (IR-PE) are scanty. Whether transthoracic echocardiography may be helpful in further risk assessment of death in such population has still to be proven. Two-hundred fifty-four consecutive patients (51.6% females, age 63.7 ± 17.3 years) with IR-PE admitted to a tertiary regional referral center were enrolled. Patients underwent a complete transthoracic echocardiography within 36 h from hospital admission, on top of clinical assessment, physical examination, computer tomography pulmonary angiography (CTPA), and serum measurement of Troponin I (TnI) levels. The occurrence of 90 day mortality was chosen as primary outcome measure. When compared to survivors, non-surviving IR-PE patients had smaller left-ventricular end-diastolic volumes (39.8 ± 20.9 vs 49.4 ± 19.9 ml/m², p = 0.006) with reduced stroke volume index (SVi) (24.7 ± 10.9 vs 30.9 ± 12.6 ml/m², p: 0.004) and time-velocity integral at left-ventricular outflow tract (VTI_LVOT) (0.17 ± 0.03 vs 0.20 ± 0.04 m, p = 0.0001), whereas no differences were recorded regarding right heart parameters. Cox regression analysis revealed that right atrial enlargement (RAE) (HR 3.432, 5-95% CI 1.193-9.876, p: 0.022), the ratio between tricuspid annulus plane excursion and pulmonary arterial systolic pressure (TAPSE/PASp) (HR 4.833, 5-95% 1.230-18.986, p = 0.024), as well as SVi (HR 11.199, 5-95% CI 2.697-48.096, p = 0.001) and VTI_LVOT (HR 4.212, 5-95% CI 1.384-12.820, p = 0.011) were powerful independent predictors of mortality. Neither CTPA RV/LV nor TnI resulted associated with impaired survival. In intermediate-risk pulmonary embolism, RAE, TAPSE/PASp ratio, SVi, and VTI_LVOT predict independently prognosis to a greater extent than CTPA and TnI.

Keywords: Critical care; Pulmonary embolism; Risk assessment; Transthoracic echocardiography.