PURPOSE: 2D echo (2DE) plays a vital role in the diagnosis and risk stratification in pulmonary embolism (PE). Acute PE results in a sudden pressure overload and can lead to right ventricular dysfunction (RVD), which is associated with worse prognosis. However RV function is difficult to quantitate in view of its unusual anatomy. Vector Velocity Imaging (VVI), a speckle tracking echocardiography technique, can assess RV and RA function, by quantitating RV long-axis shortening (RV strain σ , - %) during systole and concurrent RA expansion (RA strain σ). Accordingly, we hypothesized that VVI will demonstrate reductions in RV and RA σ in PE.
METHODS: Data from 30 patients (64 ±14 years, 16 women) with documented PE by CT angiography, who underwent 2DE within 24 hours, were compared to those of 30 normal (NLS) (54 ±17 years, 19 women). RA volume and pulmonary artery pressures (PAP) were calculated. VVI was performed off-line (TomTec). Average RV and RA σ were calculated.
RESULTS: RA volume was higher in PE (33 ±9 vs 18±5), as was PAP (45.9 ±11 vs 23.6 ±6, all p < 0.001). RV σ were lower in PE (-12.9% ±5 vs NLS -20.7 ±5%, p < 0.001). Similarly, RA σ was lower in PE (31.7% ±11 vs 55.6% ±16 in NLS, respectively, p < 0.001). Segmental RV strains were lower in both basal and mid free wall in PE. RV and RA σ showed strong inverse correlation.
CONCLUSIONS: VVI echocardiography analysis shows that RV systolic strain and RA strain are depressed in acute PE. There is a linear relationship between RV compression and RA expansion (RV/RA coupling), which is preserved in acute PE, but the absolute values for the strains are lower in acute PE.
CLINICAL IMPLICATIONS: Reduction in RA strain calculated by VVI is a novel indicator of right sided pressure overload observed in PE. We speculate that this method might provide incremental, quantitative information about RV/RA function which might help risk stratify PE patients and help direct therapy.
DISCLOSURE: The following authors have nothing to disclose: Umar Khan, Dennis Tighe, Gerard Aurigemma
Vector Velocity Imaging method for Echocardiography is a new technique and is still in research phase for study of right heart