Echocardiographic Follow-Up of Patients With Systemic Sclerosis
Echocardiographic Follow-Up of Patients With Systemic Sclerosis
21 SSc patients without pulmonary hypertension, reduced LVEF, or known coronary heart disease who were included in the DETECT (Detection of PAH in SSc) study in our centre were screened. The study protocol was approved by the ethics committee of the Charité University Hospital. All participants provided written consent. One patient refused follow-up echocardiography and one had to be excluded due to mitral valve sclerosis at baseline. Therefore, nineteen patients with SSc according to the American College of Rheumatology classification criteria (13 women, mean age 55.2 ± 10.8 years, range 33 to 74 years) with a median disease duration 6 ± 4.5 years (range 2 to 17 years) and a mean modified Rodnan Skin Score of 8.2 ± 6.5 were included into the study (Table 1). All patients underwent echocardiography with STE at baseline and 756.6 ± 8.8 days later to analyse global and regional systolic LV function. Pulmonary hypertension was ruled out in all patients by right heart catheterization (average mean PAP 17.7 ± 3.5 mmHg). Table 1 shows the baseline characteristics in detail.
Standard transthoracic echocardiography was performed in the left decubitus position using an ultrasound system (Vivid 7, GE Medical Systems, Horton, Norway) with a 3.4-MHz multifrequency transducer. The LVEF was obtained according to the recommendations of the ASE.
Left ventricular diastolic function was assessed using pulsed-wave Doppler and pulsed-wave Doppler tissue imaging (DTI) recordings on the basis of the recommendations of the ASE. Transmitral flow was acquired to obtain peak early (E) and atrial (A) flow velocities. We used the average peak early diastolic (E'), peak late diastolic (A') and peak systolic velocity (S') obtained from the septal and lateral sides of the mitral annulus in the fourchamber view with proper DTI settings. The E/E' ratio was calculated to estimate LV filling pressures.
For assessment of longitudinal strain, we recorded standard 2D ultrasound images with a frame rate between 60 and 80 frames per second (fps) from the apical long axis, and two- and four-chamber views. We stored these recordings digitally for offline analysis (EchoPac PC, Version 112.1.1, GE Vingmed, Horton, Norway) as previously described. In short, we used a semi-automatic algorithm for tracking the left ventricular myocardial wall, which was divided into 18 segments to obtain the global peak systolic longitudinal strain.
Two echocardiographers, blinded to previously obtained data, separately measured global PSS from 13 random patients for interobserver variability analysis. Additionally, an experienced observer calculated strain values twice on two consecutive days for analysis of intraobserver variability. We employed inter- and intraobserver variability to determine the interclass coefficient.
All results are expressed as mean ± standard deviation (SD). Statistics were calculated using SPSS 21.0 (IBM Corporation, Armonk, NY, USA). Wilcoxon-test was used for the comparison of the paired observations. Interclass Correlation Coefficient by Kolmogorov-Smirnov was used to calculate inter- and interobserver variability. P values of < 0.05 were considered statistically significant. The echo templates for Figure three were originally created by Patrick J. Lynch and C. Carl Jaffe, MD and used with permission under the Creative Commons Attribution 2.5 License 2006.
Methods
Study Population
21 SSc patients without pulmonary hypertension, reduced LVEF, or known coronary heart disease who were included in the DETECT (Detection of PAH in SSc) study in our centre were screened. The study protocol was approved by the ethics committee of the Charité University Hospital. All participants provided written consent. One patient refused follow-up echocardiography and one had to be excluded due to mitral valve sclerosis at baseline. Therefore, nineteen patients with SSc according to the American College of Rheumatology classification criteria (13 women, mean age 55.2 ± 10.8 years, range 33 to 74 years) with a median disease duration 6 ± 4.5 years (range 2 to 17 years) and a mean modified Rodnan Skin Score of 8.2 ± 6.5 were included into the study (Table 1). All patients underwent echocardiography with STE at baseline and 756.6 ± 8.8 days later to analyse global and regional systolic LV function. Pulmonary hypertension was ruled out in all patients by right heart catheterization (average mean PAP 17.7 ± 3.5 mmHg). Table 1 shows the baseline characteristics in detail.
Echocardiography and Conventional Doppler Measurements
Standard transthoracic echocardiography was performed in the left decubitus position using an ultrasound system (Vivid 7, GE Medical Systems, Horton, Norway) with a 3.4-MHz multifrequency transducer. The LVEF was obtained according to the recommendations of the ASE.
Left ventricular diastolic function was assessed using pulsed-wave Doppler and pulsed-wave Doppler tissue imaging (DTI) recordings on the basis of the recommendations of the ASE. Transmitral flow was acquired to obtain peak early (E) and atrial (A) flow velocities. We used the average peak early diastolic (E'), peak late diastolic (A') and peak systolic velocity (S') obtained from the septal and lateral sides of the mitral annulus in the fourchamber view with proper DTI settings. The E/E' ratio was calculated to estimate LV filling pressures.
2D Speckle Tracking Strain Analysis
For assessment of longitudinal strain, we recorded standard 2D ultrasound images with a frame rate between 60 and 80 frames per second (fps) from the apical long axis, and two- and four-chamber views. We stored these recordings digitally for offline analysis (EchoPac PC, Version 112.1.1, GE Vingmed, Horton, Norway) as previously described. In short, we used a semi-automatic algorithm for tracking the left ventricular myocardial wall, which was divided into 18 segments to obtain the global peak systolic longitudinal strain.
Inter- and Intraobserver Variability Analysis
Two echocardiographers, blinded to previously obtained data, separately measured global PSS from 13 random patients for interobserver variability analysis. Additionally, an experienced observer calculated strain values twice on two consecutive days for analysis of intraobserver variability. We employed inter- and intraobserver variability to determine the interclass coefficient.
Statistics and Figures
All results are expressed as mean ± standard deviation (SD). Statistics were calculated using SPSS 21.0 (IBM Corporation, Armonk, NY, USA). Wilcoxon-test was used for the comparison of the paired observations. Interclass Correlation Coefficient by Kolmogorov-Smirnov was used to calculate inter- and interobserver variability. P values of < 0.05 were considered statistically significant. The echo templates for Figure three were originally created by Patrick J. Lynch and C. Carl Jaffe, MD and used with permission under the Creative Commons Attribution 2.5 License 2006.
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