A novel speckle‐tracking echocardiography parameter assessing left ventricular afterload

Figures

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  Figure 1. Schematic images of LVSWI (A) and PSP (B). Y axis shows LV pressure, and X axis shows LV volume (A) and strain (B). The area surrounded by blue and green diagonal shows estimated LV stroke work and PSP, respectively. GCS (absolute value) and GRS can be used as a peak systolic strain for the calculation of PSPcirc and PSPrad, respectively. EDP, end-diastolic pressure; GCS, global circumferential strain; GRS, global radial strain; LV, left ventricular; LVSWI, left ventricular stroke work index; MAP, mean arterial pressure; PSP, Pressure-Strain Product; SVI, stroke volume index.

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  Figure 2. An example of image for the measurement of PSPcirc and PSPrad. (A) LV short axis view at mid-papillary level showing the myocardial layer (dark blue). (B) Two strain curves: endo-myocardial GCS (pink) and GRS (light blue). Each value at the end-systolic phase (eS, highlighted in yellow) was used for the calculation of PSPcirc and PSPrad. (C) Echocardiographic parameters including myocardial and endocardial GCS, EDA, ESA, FAC, GRS, and delta-rotation as the average value from the basal, mid-papillary, and apical levels. (D) Formula for calculating PSPcirc and PSPrad using endocardial GCS and GRS, respectively. EDA, end-diastolic area; ESA, end-systolic area; FAC, fractional area change; GCS, global circumferential strain; GRS, global radial strain; MAP, mean arterial pressure; PSPcirc, pressure strain product based on GCS; PSPrad, pressure strain product based on GRS. ROT, rotation; SD-CS, standard deviation of circumferential strain; SD-RS, standard deviation of radial strain.

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  Figure 3. Linear regression analysis between LVSWI and other cardiac parameters in S group. Scatter plot graphs between LVSWI and (A) CI, (B) LVEF, (C) GCS, (D) GRS, (E) PSPcirc and (F) PSPrad were described. Each assessment included the valid cases from the timepoint of baseline to 48 h following model creation. CI, cardiac index; GCS, global circumferential strain; GRS, global radial strain; LVEF, left ventricular ejection fraction; LVSWI, left ventricular stroke work index; PSPcirc, pressure strain product based on GCS; PSPrad, pressure strain product based on GRS.

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  Figure 4. Linear regression analysis between ACP and other cardiac parameters in S group. Scatter plot graphs between ACP and (A) CI, (B) LVEF, (C) GCS, (D) GRS, (E) PSPcirc and (F) PSPrad were described. Each assessment included the valid cases from the timepoint of baseline to 48 h following model creation. ACP, afterload-related cardiac performance; CI, cardiac index; GCS, global circumferential strain; GRS, global radial strain; LVEF, left ventricular ejection fraction; LVSWI, left ventricular stroke work index; PSPcirc, pressure strain product based on GCS; PSPrad, pressure strain product based on GRS.

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  Figure 5. Linear regression analysis between serum lactate and cardiac parameters in S group. Scatter plot graphs between ACP and (A) CI, (B) LVEF, (C) GCS, (D) GRS, (E) PSPcirc and (F) PSPrad are described. Each assessment included the valid cases from the timepoint of baseline to 48 h following model creation. CI, cardiac index; GCS, global circumferential strain; GRS, global radial strain; LVEF, left ventricular ejection fraction; LVSWI, left ventricular stroke work index; PSPcirc, pressure strain product based on GCS; PSPrad, pressure strain product based on GRS.

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  Figure 6. ROC curve analysis to investigate the performance of echocardiographic parameters for prediction of previously known prognostic values. Prognostic values include LVSWI, ACP and lactate. Echocardiographic parameters were compared among LVEF, GCS, GRS, PSPcirc and PSPrad. Each prognostic value (including all animals and all timepoints) was divided into either higher or lower value based on mean or median as per distribution. ACP, afterload-related cardiac performance; CI, cardiac index; GCS, global circumferential strain; GRS, global radial strain; LVEF, left ventricular ejection fraction; LVSWI, left ventricular stroke work index; PSPcirc, pressure strain product based on GCS; PSPrad, pressure strain product based on GRS.