Aortopathy in adults with tetralogy of Fallot has a negative impact on the left ventricle

Abnormal aortic flow conduction is associated with increased viscous energy loss in patients with repaired tetralogy of Fallot

OBJECTIVES

Aortopathy in tetralogy of Fallot (TOF) is characterized by increased aortic stiffness, dilation and reduced left ventricular (LV) function. Repair in infancy normalizes aortic dimensions in early childhood. Our prior work demonstrated that early TOF repair does not normalize aortic compliance and that abnormal ascending aortic flow patterns are prevalent. The objectives of this study were to: (i) determine whether proximal aortic flow-mediated viscous energy loss (EL') is elevated in patients with early TOF repair compared with healthy controls, and (ii) determine whether the degree of EL' is associated with LV function.

METHODS

Forty-one patients post TOF repair with normalized aortic size and 15 healthy controls underwent 4-dimenisonal-flow magnetic resonance imaging flow analysis and EL' assessment. Correlations between EL', aortic size, and LV function were assessed.

RESULTS

The TOF group had increased peak systolic thoracic aorta EL' (3.8 vs 1.5 mW, P = 0.004) and increased averaged EL' throughout the cardiac cycle (1.2 vs 0.5 mW, P = 0.003). Peak and mean systolic EL' in the ascending aorta was increased 2-fold in the TOF group compared with control (peak: 2.0 vs 0.9 mW, P = 0.007). Peak EL' measured along the entire thoracic aortic length correlated with LV ejection fraction (R = -0.45, P = 0.009), indexed LV end-systolic volume (R = -0.40, P = 0.010), and right ventricular end-systolic volume (R = -0.37, P = 0.034).

CONCLUSIONS

Patients with repaired TOF exhibit abnormal aortic flow associated with increased EL' in the thoracic aorta. The magnitude of EL' is associated with LV function and volumes. Increased aortic EL' in TOF is likely due to inherently abnormal LV outflow geometry and or right ventricular interaction. Reduced aortic flow efficiency in TOF increases cardiac work and may be an important factor in long-term cardiac performance.

Aortic Vorticity, Helicity, and Aortopathy in Adult Patients with Tetralogy of Fallot: Pilot Study Using Four-Dimensional Flow Magnetic Resonance Images

To employ quantitative analysis in the vorticity and helicity of the aortic root and the ascending aorta (AAo) in adults with tetralogy of Fallot (TOF), and to evaluate aortopathy and the relevant factors. Prospectively, 51 consecutive adults with TOF underwent 4 dimensional flow magnetic resonance imaging study for the assessment of vorticity and helicity of the aortic root and AAo, wall shear stress (WSS), viscous energy loss (EL), and the left ventricular outflow tract - aortic root (LVOT-Ao) angle. Patients were divided into the two groups: dilated aortic root and/or AAo (indexed diameter > 25 mm/cm²), Group A (15 patients); non-dilated aortic patients, Group B (36 patients). Ten age-matched controls were also enrolled. Group A showed more acute LVOT-Ao angle, higher incidence of aortic regurgitation, and initial anatomy of pulmonary atresia, compared to Group B (P < 0.0001, 0.02, 0.043). Group A showed greater clockwise vorticity at the level of Valsalva, AAo, and proximal arch, sagittal vorticity, AAo helicity, WSS, and EL than in Group B (P < 0.001, < 0.001, < 0.001, 0.045, 0.049, 0.02, 0.026). More acute LVOT-Ao angle correlated with the diameter of the aortic root and AAo, AAo vorticity, helicity, WSS, and EL (P = 0.004, 0.023, 0.045, 0.004, 0.0004, 0.017). On a univariate logistic analysis, more acute LVOT-Ao angle, AAo vorticity, AAo helicity, and maximum WSS were relevant factors of AAo dilatation (P = 0.02, 0.02, 0.045, 0.03, 0.046). On a multivariate logistic analysis, more acute LVOT-Ao angle was the most important factor of AAo dilatation (odds ratio 0.66, 95% CI 0.46-0.95, P < 0.024). TOF adults presenting dilated AAo have greater vorticity, helicity, and acute LVOT-Ao angle. Flow eccentricity and these flow hemodynamic parameters may be adjunctive predictions of aortopathy in this population.

Increased Aortic Stiffness and Left Ventricular Dysfunction Exist After Truncus Arteriosus Repair

BACKGROUND

The purpose of this study was to determine whether aortic biomechanical properties are abnormal in children with repaired truncus arteriosus (TA) and to concurrently evaluate left ventricular (LV) function post-repair utilizing a novel platform for regional ventricular function.

METHODS

Cardiac magnetic resonance (CMR) studies from 26 children (mean age: 15.6 ± 7.2 years) post-TA repair were compared with 20 normal controls (mean age: 14.7 ± 2.6 years). Parameters of aortic stiffness (pulse wave velocity and relative area change) were measured. Flow hemodynamic metrics (aortic regurgitant fraction, peak systolic flow, and peak systolic velocity) and LV function (volumetric data, ejection fraction, regional wall strain) were also compared.

RESULTS

Ascending aortic pulse wave velocity was elevated and relative area change was decreased in TA patients compared with controls. Patients post-TA repair demonstrated elevated end diastolic and end systolic volumes in addition to decreased regional wall strain and increased mechanical dyssynchrony. LV functional changes were independent of aortic biomechanical properties.

CONCLUSIONS

Children with repaired TA have increased ascending aortic stiffness and altered LV function as measured by CMR imaging. Longitudinal studies and advanced CMR assessments are warranted to better determine the long-term potential for late aortic complications and to optimize both the medical and surgical management of these patients after TA repair.

Effect of Stiffened and Dilated Ascending Aorta on Aerobic Exercise Capacity in Repaired Patients With Complex Congenital Heart Disease

Several studies have reported aortic dilation and increased stiffness of the ascending aorta in patients after repair of congenital heart disease (CHD), which may be a predominant cardiovascular risk. However, the clinical significance has not been described in detail. In this retrospective study, 175 repaired patients with complex CHD achieving biventricular circulation and age-matched 39 control subjects were reviewed (median age: 14.9 and 15.7 years, respectively). We measured the diameters of the ascending aorta and descending aorta from catheterization angiograms to yield Z-scores and stiffness indexes (β) using diameter fluctuations corresponding to pulsatile pressures. Clinical profile, peak oxygen uptake during the cardiopulmonary exercise test, and incidence of unscheduled hospitalization during follow-up was also reviewed. Compared with controls, patients with complex CHD, except for those with aortic coarctation, exhibited significant dilation and increased stiffness of the aortic root and ascending aorta, but not of the descending aorta. In this CHD population (n = 147, including 112 conotruncal anomalies), exercise capacities correlated independently with the diameter Z-score and stiffness index of the ascending aorta along with the history of repetitive thoracotomies, reduced forced vital capacity, and right ventricular hypertension. During a follow-up period (median 15.6 years), either dilation (Z-score >3.5) or increased stiffness (β >6.0) of the ascending aorta stratified morbidity, but no synergistic impact was detected. In conclusion, in repaired patients with complex CHD, a stiffened and dilated ascending aorta was frequently found, exerting significant adverse impacts on diminished exercise capacity and morbidity.

Ventricular Myocardial Deformation Imaging of Patients with Repaired Tetralogy of Fallot

In patients with repaired tetralogy of Fallot (TOF), dysfunction of the right and left ventricles remains an important issue. Adverse right ventricular (RV) remodeling has been related to RV dilation secondary to pulmonary regurgitation, electromechanical dyssynchrony, and myocardial fibrosis. Left ventricular (LV) dysfunction is attributed among other factors to altered ventricular-ventricular interaction. Advancements in echocardiography and cardiac magnetic resonance imaging have enabled direct interrogation of myocardial deformation of both ventricles in terms of myocardial strain and strain rate. Emerging evidence suggests that myocardial deformation imaging may provide incremental information for clinical use. In children and adults with repaired TOF, there is a growing body of literature on the use of myocardial deformation imaging in the assessment of ventricular mechanics and its clinical and prognostic values. The present review aims to provide an overview of impairment in RV and LV mechanics, associations between RV and LV deformation, changes in ventricular deformation after pulmonary valve replacement, and associations between measures of RV and LV deformation and outcomes and to highlight the clinical translational potential of myocardial deformation imaging in patients with repaired TOF.

Association of aortic root dilatation with left ventricular function in patients with postoperative ventricular septal defect

Proximal aortic enlargement is associated with an increased risk of heart failure and all-cause mortality. Recently, aortic root dilatation (ARD) was reported in postoperative patients with ventricular septal defects (VSDs). However, the impact of ARD on left ventricular (LV) function in postoperative VSD patients remains unclear. Thus, the aim of this study was to investigate the effect of ARD on LV function in patients with postoperative VSD. One hundred and thirty-five patients (> 15 years of age) with surgically repaired isolated ventricular defects and who underwent transthoracic echocardiography in our institution between 2009 and 2013 were identified. ARD was defined as an observed aortic root diameter/body surface area > 2.1 cm/m². The propensity score estimating the probability of having ARD adjusted for anatomical and clinical characteristics was calculated. Forty-four patients (32.6%) had ARD. In unadjusted analyses, right ventricular systolic pressure, Tei index, and E/e' were significantly (p < 0.05) higher in patients with ARD than in those without ARD (31.3 ± 7.5 vs. 35.4 ± 13.7 mmHg, 0.32 ± 0.10 vs. 0.44 ± 0.15, and 7.1 ± 1.7 vs. 9.5 ± 2.9, respectively). In the propensity score-adjusted analysis, significant differences in the Tei index and E/e' were confirmed between the two groups (Tei index difference: 0.11, 95% confidence interval 0.05-0.17; E/e' difference: 2.4, 95% confidence interval 1.3-3.5). However, there were no differences in the other echocardiographic measurements. The presence of ARD in patients with postoperative VSD was significantly associated with LV diastolic dysfunction. Thus, surgically repaired VSD patients require careful screening for aortic enlargement and LV function.

Circulating Transforming Growth Factor-β and Aortic Dilation in Patients with Repaired Congenital Heart Disease

This study determined the circulating levels of TGF-β1 and its association with aortic dilation and elastic properties in congenital heart patients. Forty-six patients after tetralogy of Fallot (TOF) repair, 21 patients post arterial switch and 15 patients post atrial switch for transposition of the great arteries (TGA), 27 patients post Fontan procedure, and 36 controls were studied. Aortic dimensions and elastic properties and ventricular function were assessed by echocardiography. Serum TGF-β1, metalloproteinase (MMP)-2 and MMP-9 levels were quantified. Compared with controls, all groups of patients had significantly larger ascending aortic dimensions and worse elastic properties (all p < 0.05). Aortic stiffness correlated positively with sinus dimension (r = 0.48, p < 0.001) and negatively with indices of ventricular deformation (all p < 0.001). Patients with repaired TOF had significantly higher levels of TGF-β1 (p = 0.005), MMP-2 (p = 0.001) and MMP-9 (p < 0.001) than controls, while patients after atrial switch operation (p = 0.034) and Fontan procedures (p < 0.001) had higher MMP-2 levels. In patients as a group, circulating TGF-β1 levels correlated with MMP-9 (r = 0.44, p < 0.001) and aortic sinus dimension (r = 0.22, p = 0.035). In conclusion, increased circulating TGF-β1, MMP-2, and MMP-9 levels were found in patients with repaired TOF, and increased circulating MMP-2 levels were also evident in patients after atrial switch operation and Fontan procedure.