Left Ventricular Strain Normalizes After Balloon Aortic Valvuloplasty in Infants with Congenital Aortic Stenosis

Left ventricular systolic function impairment in children after balloon valvuloplasty for congenital aortic stenosis assessed by 2D speckle tracking echocardiography

AIMS

The aim of the study was to evaluate left ventricular (LV) remodeling and systolic function using two-dimensional speckle tracking echocardiographic (2D STE) imaging in children at a long-term (more than 36 months, 107.5±57.8 months) after balloon valvuloplasty for aortic stenosis (BAV).

METHODS AND RESULTS

40 patients (mean age 9,68 years, 75% male) after BAV and 62 control subjects matched to the age and heart rate were prospectively evaluated. The 2D STE assessment of LV longitudinal and circumferential strain and strain rate was performed. Left ventricular eccentric hypertrophy (LVEH) was diagnosed in 75% of patients in the study group. Left ventricular ejection fraction (LVEF) was normal in all patients. In study group, global longitudinal strain (GLS), global longitudinal strain rate (GLSr) were significantly lower compared with the controls: GLS (-19.7±2.22% vs. -22.3±1.5%, P< 0.001), GLSr (-0.89±0.15/s vs. -1.04 ±0.12/s, P < 0.001). Regional (basal, middle and apical segments) strain and strain rate were also lower compared with control group. Global circumferential strain (GCS), global circumferential strain rate (GCSr) as well as regional (basal, middle and apical segments) strain and strain rate were normal. Multivariable logistic regression analysis included: instantaneous peak systolic Doppler gradient across aortic valve (PGmax), grade of aortic regurgitation (AR), left ventricular mass index (LVMI), left ventricular relative wall thickness (LVRWT), left ventricular end-diastolic diameter (LVEDd), peak systolic mitral annular velocity of the septal and lateral corner (S'spt, S'lat), LVEF before BAV and time after BAV and showed that the only predictor of reduced GLS was LV eccentric hypertrophy [odds ratio 6.9; (95% CI: 1.37-12.5), P = 0.045].

CONCLUSION

Patients at long-term observation after BAV present the subclinical LV systolic impairment, which is associated with the presence of its remodeling. Longitudinal deformation is the most sensitive marker of LV systolic impairment in this group of patients.

Myocardial work index: a marker of left ventricular contractility in pressure- or volume overload-induced heart failure

Aims

While global longitudinal strain (GLS) is considered to be a sensitive marker of left ventricular (LV) function, it is significantly influenced by loading conditions. We hypothesized that global myocardial work index (GMWI), a novel marker of LV function, may show better correlation with load‐independent markers of LV contractility in rat models of pressure‐induced or volume overload‐induced heart failure.

Methods and results

Male Wistar rats underwent either transverse aortic constriction (TAC; n = 12) or aortocaval fistula creation (ACF; n = 12), inducing LV pressure or volume overload, respectively. Sham procedures were performed to establish control groups (n = 12/12). Echocardiographic loops were obtained to determine GLS and GMWI. Pressure‐volume analysis with transient occlusion of the inferior caval vein was carried out to calculate preload recruitable stroke work (PRSW), a load‐independent ‘gold‐standard’ parameter of LV contractility. Myocardial samples were collected to assess interstitial and perivascular fibrosis area and also myocardial atrial‐type natriuretic peptide (ANP) and brain‐type natriuretic peptide (BNP) relative mRNA expression. Compared with controls, GLS was substantially lower in the TAC group (−7.0 ± 2.8 vs. −14.5 ± 2.5%; P < 0.001) and was only mildly reduced in the ACF group (−13.2 ± 2.4 vs. −15.4 ± 2.0%, P < 0.05). In contrast with these findings, PRSW and GMWI were comparable with sham in TAC (110 ± 26 vs. 116 ± 68 mmHg; 1687 ± 275 mmHg% vs. 1537 ± 662 mmHg%; both P = NS), while it was found to be significantly reduced in ACF (58 ± 14 vs. 111 ± 40 mmHg; 1328 ± 411 vs. 1934 ± 308 mmHg%, both P < 0.01). In the pooled population, GMWI (r = 0.70; P < 0.001) but not GLS (r = −0.23; P = 0.12) showed a strong correlation with PRSW. GLS correlated with interstitial (r = 0.61; P < 0.001) and perivascular fibrosis area (r = 0.54; P < 0.001), and also with myocardial ANP (r = 0.85; P < 0.001) and BNP relative mRNA expression (r = 0.75; P < 0.001), while GMWI demonstrated no or only marginal correlation with these parameters.

Conclusions

Being significantly influenced by loading conditions, GLS may not be a reliable marker of LV contractility in heart failure induced by pressure or volume overload. GMWI better reflects contractility in haemodynamic overload states, making it a more robust marker of systolic function, while GLS should be considered as an integrative marker, incorporating systolic function, haemodynamic loading state, and adverse tissue remodelling of the LV.