Intellispace cardiovascular ultrasound viewer

Echocardiographic assessment was conducted by one investigator using a Philips iE33 xMatrix or a Philips Epiq 7G ultrasound device (Philips Healthcare, The Netherlands) with a 1–5 or a 3–8 MHz sector ultrasound transducer (Philips Healthcare, The Netherlands). Three consecutive loops were recorded under constant ECG-tracking and heart rate (bpm) was determined. Images were transferred to an offline workstation (IntelliSpace Cardiovascular Ultrasound Viewer, Philips Healthcare, The Netherlands) for analysis. Analysis for two-dimensional speckle tracking echocardiography (2DSTE) was conducted on a separate workstation (QLAB cardiovascular ultrasound quantification software, version 11.1, Philips Healthcare, The Netherlands). The offline assessment of LV systolic function was performed by one investigator for both groups.

The aortic velocity time integral (aVTI, cm) was assessed in apical five chamber view through pulsed wave Doppler by placing the sample volume over the aortic valve. aVTI was manually determined in an offline analysis (IntelliSpace Cardiovascular Ultrasound Viewer, Philips Healthcare, The Netherlands) by tracing the area under the spectral curve.

The abovementioned sonographic study protocol was applied. M-Mode of the AAO was performed in short axis view under three-lead ECG tracking using a 3–8 MHz sector or a 1–5 MHz sector array transducer. M-Mode of both CCA was carried out in long axis view under three-lead ECG tracking utilizing a 3–12 MHz linear array transducer.
For all study participants, the end-diastolic diameter (dD, mm) and the end-systolic diameter (sD, mm) of the AAO and both CCA were measured offline (IntelliSpace Cardiovascular Ultrasound Viewer, Philips Healthcare, Amsterdam, The Netherlands) by one investigator.
The stiffness index β (unitless) was calculated for the AAO in short axis and for both CCA in long axis as [7 (link)]: $$\mathrm{Stiffness} \mathrm{Index} \mathsf{\beta }=\frac{\ln \left(\frac{\mathrm{SBP}}{\mathrm{DBP}}\right)}{∆\mathrm{D}/\mathrm{dD}}.$$
ΔD (mm) was defined as the difference of sD and dD. SBP and DBP assessed by the Mobil-O-Graph^® were utilized for this calculation.