Right Ventricular Strain Impairment in Adults and Adolescents with Repaired Aortic Coarctation

Left ventricular adaptation to aortic regurgitation in adults with repaired coarctation of aorta

BACKGROUND

Aortic regurgitation (AR) can develop in adults with repaired coarctation of aorta (COA), but there are limited data about left ventricular (LV) remodeling and clinical outcomes in this population. The purpose of the study was to compare LV remodeling (LV mass index [LVMI], LV ejection fraction [LVEF], and septal E/e') and onset of symptoms before aortic valve replacement, and LV reverse remodeling (%-change in LVMI, LVEF and E/e') after aortic valve replacement in patients with versus without repaired COA presenting with AR.

METHODS

Asymptomatic adults with repaired COA presenting with moderate/severe AR (AR-COA group) were matched 1:2 to asymptomatic adults without COA and similar severity of AR (control group).

RESULTS

Although both groups (AR-COA n = 52, and control n = 104) had similar age, sex, body mass index, aortic valve gradient, and AR severity, the AR-COA group had higher LVMI (124 ± 28 versus 102 ± 25 g/m², p < 0.001) and E/e' (12.3 ± 2.3 versus 9.5 ± 2.1, p = 0.02) but similar LVEF (63 ± 9% versus 67 ± 10%, p = 0.4). COA diagnosis (adjusted HR 1.95, 95%CI 1.49-2.37, p < 0.001), older age, E/e', and LV hypertrophy were associated with onset of symptoms. Of 89 patients (AR-COA n = 41, and control n = 48) with echocardiographic data at 1-year post- aortic valve replacement, the AR-COA group had less regression of LVMI (-8% [95%CI -5 to -11] versus -17% [95%CI -15 to -21], p < 0.001) and E/e' (-5% [95% CI -3 to -7] versus -16% [95% CI -13 to -19], p < 0.001).

CONCLUSIONS

Patients with COA and AR had a more aggressive clinical course, and perhaps may require a different threshold for surgical intervention.

Strain Estimation of the Murine Right Ventricle Using High-Frequency Speckle-Tracking Ultrasound

Right ventricular (RV) strain measurements from ultrasound via speckle-tracking techniques are being used more frequently as a non-invasive diagnostic tool for a variety of cardiopulmonary pathologies. However, despite the clinical utility of ultrasound RV strain measurements, quantification of RV strain in rodents remains difficult owing to unique image artifacts and non-standardized methodologies. We demonstrate here a simple approach for measuring RV strain in both mice and rats using high-frequency ultrasound and automated speckle tracking. Our results show estimated peak RV free-wall longitudinal strain values (mean ± standard error of the mean) in mice (n = 15) and rats (n = 5) of, respectively, -10.38% ± 0.4% and -4.85% ± 0.42%. We further estimated the 2-D Green-Lagrange strain within the RV free wall, with longitudinal components estimated at -5.7% ± 0.48% in mice and -2.1% ± 0.28% in rats. These methods and data may provide a foundation for future work aimed at evaluating murine RV strain levels in different disease models.