Comparison of Right Ventricular Systolic Function in Patients with Low Risk and Intermediate‐to‐High Risk Pulmonary Embolism: A Two‐Dimensional Strain Imaging Study

AIM: Right ventricular (RV) dysfunction is key for risk stratification in pulmonary embolism (PE). The goal of this study was to compare RV strain values between low and intermediate-to-high risk PE patients assessed by two-dimensional (2D) strain imaging. METHODS: The inclusion criterion was a diagnosis of PE confirmed by thoracic computed tomography scan with contrast medium, or by scintigraphy perfusion lung scan. Risk stratification of PE was defined as high when there was hemodynamic instability; intermediate when there were signs of RV dysfunction on echocardiography; and/or elevated troponin I and/or brain natriuretic peptide and low when none of these criteria were present. All patients underwent echocardiography at admission. Apical four-chamber images were analyzed off line using both conventional and 2D strain imaging. RESULTS: Sixty-two patients (mean age 66 years) were prospectively recruited: 33 with low risk PE, 29 with intermediate-to-high risk PE. Global 2D RV strain differed significantly between groups (-13.1% vs. -18.7%, P < 0.01), as did free wall (-12.7% vs. -20.2%, P < 0.016) and septal wall (-13.5% vs. -17.2%, P < 0.01). When the RV was divided into segments, we observed a similar reduction in absolute strain value in the mid and apical free wall segments and in the apical septal wall (-20.3 ± -7.6 vs. -11.8 ± 8.9%; P < 0.01 and -19.6 ± 6.9 vs. -7.4 ± 9.1%; P < 0.01, and -17.7 ± 7.0 vs. 9.9 ± 8.0; P < 0.01, respectively). 2D strain and tricuspid annular plane systolic excursion were significantly related (r(2) = 0.35, P < 0.01). CONCLUSIONS: Peak RV longitudinal 2D strain is reduced in patients with intermediate-to-high risk PE, especially in the apical and mid segments of the free wall. Global and regional RV longitudinal 2D strain is altered in patients with intermediate-to-high risk PE as compared with low risk PE.