Advanced echocardiographic assessment in adults with repaired aortic coarctation: myocardial work analysis provides novel insights on left ventricular mechanics

Abstract

Aim: To analyze left ventricular (LV) mechanics through advanced echocardiography, including speckle tracking analysis and myocardial work (MW) in a cohort of adults with repaired aortic coarctation (CoA).

Methods: Data on standard echocardiography, LV speckle-tracking and MW analysis were collected in CoA patients > 18 years with no significant recoartation or valvular disease and normal LV ejection fraction at the time of the exam. MW indices were calculated using the blood pressure measured in the right arm. A group of healthy subjects with comparable sex, age and body surface area was included for comparison.

Results: Eighty-nine CoA patients and 70 healthy subjects were included. Patients had higher systolic blood pressure (p < 0.0001), LV mass index (p < 0.0001), left atrial volume index (p = 0.005) and E/E' ratio (p = 0.001). Despite similar LV ejection fraction, speckle tracking analysis revealed lower global longitudinal strain (GLS: - 18.3[17-19] vs - 20.7[19-22]%, p < 0.0001) and increased peak systolic dispersion (PSD: 45[40-54] vs 37.5[32-43] ms, p < 0.0001) in CoA patients. Global work index (GWI) and global constructive work were similar to healthy controls (p = 0.6 and 0.5, respectively), whereas CoA patients showed significant increased wasted work (GWW: 125[90-185] vs 89.5[64-127]mmHg%, p < 0.0001) and a mild but significant reduction in global work efficiency (GWE: 93%[92-95] vs 95%[94-97], p < 0.0001). Moreover, when stratifying for GLS values, MW analysis showed increased GWW and PSD with impaired GWE in 54(61%) patients with normal GLS compared to healthy individuals. Spearman's linear method illustrated an inverse relation between GWE and PSD (r: - 0.53, p < 0.0001), while GCW was associated with peak (r: 0.2, p = 0.01) and mean gradient across the descending aorta (r: 0.3, p = 0.004) and with systolic blood pressure (r: 0.48, p < 0.0001). PSD was the sole univariate predictor of GWE on linear regression analysis (β: - 0.1 [- 0.16 to - 0.07], p < 0.0001), whereas female sex, SBP and gradients across the descending aorta were independently associated with higher GCW values. When CoA patients were divided based on the history of redo CoA repair and arterial hypertension, no significant differences in MW indices were found.

Conclusions: MW is a novel echocardiographic tool, which provides additional information on LV performance in CoA patients over GLS allowing a more comprehensive understanding of LV dysfunction mechanisms in a setting of increased afterload.

Keywords: Adult congenital heart disease; Aortic coarctation; Global wasted work; Myocardial efficiency; Myocardial work.