The goal of our study was to investigate the potential of myocardial shear wave imaging (SWI) to quantify the diastolic myocardial stiffness (MS) (kPa) noninvasively in adult healthy volunteers (HVs) ...and its physiological variation with age, and in hypertrophic cardiomyopathy (HCM) populations with heart failure and preserved ejection function (HFpEF).
MS is an important prognostic and diagnostic parameter of the diastolic function. MS is affected by physiological changes but also by pathological alterations of extracellular and cellular tissues. However, the clinical assessment of MS and the diastolic function remains challenging. SWI is a novel ultrasound-based technique that has the potential to provide intrinsic MS noninvasively.
We prospectively included 80 adults: 60 HV (divided into 3 groups: 20- to 39-year old patients n = 20; 40- to 59-year-old patients n = 20; and 60- to 79-year-old patients n = 20) and 20 HCM-HFpEF patients. Echocardiography, cardiac magnetic resonance imaging and biological explorations were achieved. MS evaluation was performed using an ultrafast ultrasound scanner with cardiac phased array. The fractional anisotropy of MS was also estimated.
MS increased significantly with age in the HV group (the mean MS was 2.59 ± 0.58 kPa, 4.70 ± 0.88 kPa, and 6.08 ± 1.06 kPa for the 20- to 40-year-old, 40- to 60-year-old, and 60- to 80-year-old patient groups, respectively; p < 0.01 between each group). MS was significantly higher in HCM-HFpEF patients than in HV patients (mean MS = 12.68 ± 2.91 kPa vs. 4.47 ± 1.68 kPa, respectively; p < 0.01), with a cut-off at 8 kPa (area under the curve = 0.993; sensitivity = 95%, specificity = 100%). The fractional anisotropy was lower in HCM-HFpEF (mean = 0.133 ± 0.073) than in HV (0.238 ± 0.068) (p < 0.01). Positive correlations were found between MS and diastolic parameters in echocardiography (early diastolic peak/early diastolic mitral annular velocity, r = 0.783; early diastolic peak/transmitral flow propagation velocity, r = 0.616; left atrial volume index, r = 0.623) and with fibrosis markers in cardiac magnetic resonance (late gadolinium enhancement, r = 0.804; myocardial T1 pre-contrast, r = 0.711).
MS was found to increase with age in healthy adults and was significantly higher in HCM-HFpEF patients. Myocardial SWI has the potential to become a clinical tool for the diagnostic of diastolic dysfunction. (Non-invasive Evaluation of Myocardial Stiffness by Elastography Elasto-Cardio; NCT02537041)
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Abstract
OBJECTIVES
To evaluate the precise dimensions of the normal aortic root, especially the true aortic annulus, during the cardiac cycle using an innovative reconstruction method based on ...multiphase cardiac computed tomography and to assess the feasibility and the reproducibility of this method for aortic root analysis.
METHODS
Between January 2019 and June 2021, 30 optimal consecutive ECG-gated multiphase cardiac computed tomography of patients with normal tricuspid aortic valve were analysed using an in-house software. Aortic annulus border was pinpointed on 9 reconstructed planes and the 3D coordinates of the 18 consecutive points were interpolated into a 3D curve using a cubic spline. Three additional planes were generated at the level of the left ventricular outflow tract, the level of the Valsalva sinus and the level of the sinotubular junction. This procedure was repeated for all the 10 temporal phases of the RR interval.
RESULTS
The aortic annulus mean 3D and 2D areas were 7.67 ± 1.51 and 5.16 ± 1.40 cm2, respectively. The mean 2D diameter was 2.51 ± 0.23 cm. The mean global area expansion was 11.8 ± 3.5% and the mean perimeter expansion of 7.1 ± 2.6%. During the cardiac cycle, the left ventricle outflow tract expands, reaching its maximum surface at the end of diastole, followed by the aortic annulus, the Valsalva sinuses and the sinotubular junction. The aorta changes from a clover-shaped cone during diastole to more cylindrical shape during systole. Compared to the 3D measurements, the analysis of the virtual basal ring significantly underestimates the annulus area, perimeter, and mean diameter.
CONCLUSIONS
4D morphometric analysis enables to have a precise and reproducible evaluation of the aortic annulus. The aortic annulus and root are deformable structures that undergo a unique expansion sequence during the cardiac cycle which should be considered for procedural planning.
For decades, surgical aortic valve replacement has been considered the gold standard for patients with aortic valve pathologies, especially aortic stenosis 1, 2.
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