Background: Left ventricular (LV) kinetic energy (KE) assessment by four-dimensional flow cardiovascular magnetic resonance (4D flow CMR) may offer incremental value over routine assessment in... Show moreBackground: Left ventricular (LV) kinetic energy (KE) assessment by four-dimensional flow cardiovascular magnetic resonance (4D flow CMR) may offer incremental value over routine assessment in aortic stenosis (AS). The main objective of this study is to investigate the LV KE in patients with AS before and after the valve intervention. In addition, this study aimed to investigate if LV KE offers incremental value for its association to the six-minute walk test (6MWT) or LV remodelling post-intervention.Methods: We recruited 18 patients with severe AS. All patients underwent transthoracic echocardiography for mean pressure gradient (mPG), CMR including 4D flow and 6MWT. Patients were invited for post-valve intervention follow-up CMR at 3 months and twelve patients returned for follow-up CMR. KE assessment of LV blood flow and the components (direct, delayed, retained and residual) were carried out for all cases. LV KE parameters were normalised to LV end-diastolic volume (LVEDV).Results: For LV blood flow KE assessment, the metrics including time delay (TD) for peak E-wave from base to mid-ventricle (14 +/- 48 vs. 2.5 +/- 9.75 ms, P=0.04), direct (4.91 +/- 5.07 vs. 1.86 +/- 1.72 mu J, P=0.01) and delayed (2.46 +/- 3.13 vs. 1.38 +/- 1.15 mu J, P=0.03) components of LV blood flow demonstrated a significant change between preand post-valve intervention. Only LV KEi(EDV) (r=-0.53, P<0.01), diastolic KEi(EDV) (r=-0.53, P<0.01) and E-wave KEi(EDV) (r=-0.38, P=0.04) demonstrated association to the 6MWT. However, Pre-operative LV KEi(EDV) (r=0.67, P=0.02) demonstrated association to LV remodelling post valve intervention.Conclusions: LV blood flow KE is associated with 6MWT and LV remodelling in patients with AS. LV KE assessment provides incremental value over routine LV function and pressure gradient (PG) assessment in AS. Show less
Assessment of right ventricular (RV) diastolic function is not routinely carried out. This is due to standard two-dimensional imaging techniques being unreliable. Four-dimensional flow (4D flow)... Show moreAssessment of right ventricular (RV) diastolic function is not routinely carried out. This is due to standard two-dimensional imaging techniques being unreliable. Four-dimensional flow (4D flow) derived right ventricular blood flow kinetic energy assessment could circumvent the issues of the current imaging modalities. It also remains unknown whether there is an association between right ventricular blood flow kinetic energy (KE) and healthy ageing. We hypothesise that healthy ageing requires maintaining normal RV intra-cavity blood flow as quantified using KE method. The main objective of this study was to investigate the effect of healthy ageing on tricuspid through-plane flow and right ventricular blood flow kinetic energy. In this study, fifty-three healthy participants received a 4D flow cardiovascular magnetic resonance (CMR) scan on 1.5T Philips Ingenia. Cine segmentation and 4D flow analysis were performed using dedicated software. Standard statistical methods were carried out to investigate the associations. Both RV E-wave KEi(EDV) (r=-0.3, P=0.04) and A-wave KEi(EDV) (r=0.42, P<0.01) showed an association with healthy ageing. Additionally, the right ventricular blood flow KEi(EDV) E/A ratio demonstrated the strongest association with healthy ageing (r=-0.53, P<0.01) when compared to all RV functional and haemodynamic parameters. Furthermore, in a multivariate regression model, KEi(EDV) E/A ratio and 4D flow derived tricuspid valve stroke volume demonstrated independent association to healthy ageing (beta -0.02 and 0.68 respectively, P<0.01). Ageing is independently associated with 4D flow derived tricuspid stroke volume and RV blood flow KE E/A ratio. These novel 4D flow CMR derived imaging markers have future potential for RV diastolic assessment. Show less
