Page 34 - Advanced echocardiography in characterization and management of patients with secondary mitral regurgitation

Chapter two. Sex differences in prognosis of significant secondary mitral regurgitation
Echocardiography
Transthoracic echocardiography was performed with commercially available systems (General Electric Vingmed Ultrasound, Milwaukee, USA), and images were digitally stored for offline analysis (EchoPAC 201.0.0, General Electric Vingmed Ultrasound, Milwaukee, USA). Image acquisition was performed with patients in hemodynamic stable conditions at rest in the left lateral decubitus position. Using 3.5 MHz or M5S transducers two-dimensional images, M-mode and Doppler data were acquired from parasternal, apical and subcostal views. From the apical 2- and 4-chamber views, left ventricular (LV) volumes (end-diastolic and end-systolic) were measured and the LV ejection fraction (EF) was quantified using the Simpson’s biplane method 12. LV volumes were indexed for body surface area. MR severity was assessed using a multiparametric approach according to current guidelines and graded as moderate (grade 2), moderate-to-severe (grade 3) and severe (grade 4) 13-15. From standard 2-dimensional transthoracic echocardiography, LV global longitudinal strain (GLS) was measured using apical 4-chamber, 2-chamber and long-axis views of the LV and processed offline using commercially available software (EchoPAC 201.0.0, General Electric Vingmed Ultrasound, Milwaukee, USA) 16. LV GLS is a measure of global shortening of the myocardium and is conventionally expressed as negative values. However, in this study we have treated this variable as absolute value and therefore, a higher LV GLS value represents better LV systolic function.
Follow-up
Patients were followed-up for the occurrence of the primary endpoint of all-cause mortality. The follow-up started from the date of the first echocardiogram showing significant secondary MR. Data on survival were collected from the departmental cardiology information system (EPD-Vision 11.8.4.0; Leiden University Medical Center, Leiden, The Netherlands) which is linked to the governmental death registry database. Follow-up was complete for all patients.
Statistical analysis
Continuous data are presented as mean ± standard deviation (when normally distributed) or as median with interquartile range (when not normally distributed). An independent sample Student t-test or Mann-Whitney U test (when appropriate) was used for the comparison of continuous data. Categorical data are presented as absolute numbers and percentages and a ▪2-test was used for the comparison between groups. To estimate the cumulative survival rates, a Kaplan-Meier analysis was performed and the log-rank test was used to compare the cumulative survival rates between men and women. Based on the Kaplan-Meier analysis, a post hoc landmark analysis was
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