Endothelial function state following repair of cyanotic congenital heart diseases

Association of Cardiovascular Disease with Retinopathy of Prematurity

PURPOSE

To determine the associations of presence and types of cardiovascular diseases (CVDs) with development of retinopathy of prematurity (ROP) in premature infants undergoing ROP examinations.

STUDY DESIGN

We performed secondary analyses of data from the multi-center Postnatal Growth and ROP Validation Study (GROP-2). CVD was categorized based on pulmonary blood flow (PBF), systemic blood flow (SBF), pulmonary hypertension (PPHN), or dysrhythmia. Adjusted odds ratios (aOR) and 95% confidence intervals (95% CI) were calculated from multivariable logistic regression models that included any ROP or severe ROP as outcome variable and any CVD or type of CVD as independent variable, with adjustment of covariates including birth weight (BW), gestational age (GA), and days on supplemental oxygen in the first month of postnatal life.

RESULT

Among 3980 infants, 528 (13.3%) had CVD (304 had increased PBF, 101 had decreased PBF, and 49 had PPHN), 1643 (40.4%) developed ROP, and 503 (12.6%) developed severe ROP. In multivariable analyses, presence of CVD was not significantly associated with increased risk of any ROP (aOR = 1.15, 95% CI: 0.90-1.46, p = .26) or severe ROP (aOR = 0.98, 95% CI: 0.72-1.34, p = .92). However, there were trends associating CVD resulting in increased PBF with a higher risk of ROP (aOR = 1.32, 95% CI: 0.97-1.80, p = .08) and PPHN with a higher risk of severe ROP (aOR = 2.04, 95% CI: 0.96-4.35, p = .07). When adjusting only for BW and GA, these associations were significant (aOR = 1.47, 95% CI: 1.09-1.99, and aOR = 2.35, 95% CI: 1.19-4.65, respectively).

CONCLUSION

CVD with increased PBF likely increases the risk of ROP. PPHN likely increases the risk of severe ROP.

Characterization of Flow Dynamics in the Pulmonary Bifurcation of Patients With Repaired Tetralogy of Fallot: A Computational Approach

The hemodynamic environment of the pulmonary bifurcation is of great importance for adult patients with repaired tetralogy of Fallot (rTOF) due to possible complications in the pulmonary valve and narrowing of the left pulmonary artery (LPA). The aim of this study was to computationally investigate the effect of geometrical variability and flow split on blood flow characteristics in the pulmonary trunk of patient-specific models. Data from a cohort of seven patients was used retrospectively and the pulmonary hemodynamics was investigated using averaged and MRI-derived patient-specific boundary conditions on the individualized models, as well as a statistical mean geometry. Geometrical analysis showed that curvature and tortuosity are higher in the LPA branch, compared to the right pulmonary artery (RPA), resulting in complex flow patterns in the LPA. The computational analysis also demonstrated high time-averaged wall shear stress (TAWSS) at the outer wall of the LPA and the wall of the RPA proximal to the junction. Similar TAWSS patterns were observed for averaged boundary conditions, except for a significantly modified flow split assigned at the outlets. Overall, this study enhances our understanding about the flow development in the pulmonary bifurcation of rTOF patients and associates some morphological characteristics with hemodynamic parameters, highlighting the importance of patient-specificity in the models. To confirm these findings, further studies are required with a bigger cohort of patients.

Physical Activity Is Associated With Better Vascular Function in Children and Adolescents With Congenital Heart Disease

BACKGROUND

Aortic stiffness is an important marker of cardiovascular risk and is elevated in children and adolescents with congenital heart disease (CHD) compared with healthy children; however, in children with CHD, little is known about the interaction between aortic stiffness and physical activity-a key determinant of aortic stiffness.

METHODS

For this cross-sectional cohort study, we recruited children and adolescents aged 9-16 years with moderate-to-complex CHD from British Columbia Children's Hospital and travelling partnership clinics across the province of British Columbia and the Yukon territory. Mean daily minutes of moderate-to-vigorous physical activity were objectively assessed using an ActiGraph accelerometer worn over the right hip during waking hours for 7 days. Aortic pulse wave velocity (cm/s) was measured using standard 2-dimensional echocardiography and Doppler ultrasound.

RESULTS

Participants (n = 104, 61% male; 85% consent rate) had a mean (standard deviation) age of 12.4 (2.4) years. Daily moderate-to-vigorous physical activity was 46.7 (20.0) minutes/d, with 25% meeting guidelines of ≥ 60 minutes of moderate-to-vigorous physical activity per day. Mean (standard deviation) aortic pulse wave velocity was 490.5 (161.9) cm/s, which was not significantly different between cardiac diagnoses. Higher levels of moderate-to-vigorous physical activity were associated with lower aortic pulse wave velocity (r = -0.226, P = 0.021).

CONCLUSION

In children and adolescents with CHD, higher levels of physical activity are associated with better vascular function. Given this association, promoting physical activity should be a high priority in the care of children and adolescents with CHD.

Peripheral Endothelial Function After Arterial Switch Operation for D-looped Transposition of the Great Arteries

Coronary artery re-implantation during arterial switch operation in patients with D-looped transposition of the great arteries (D-TGA) can alter coronary arterial flow and increase shear stress, leading to local endothelial dysfunction, although prior studies have conflicting results. Endothelial pulse amplitude testing can predict coronary endothelial dysfunction by peripheral arterial testing. This study tested if, compared to healthy controls, patients with D-TGA after arterial switch operation had peripheral endothelial dysfunction. Patient inclusion criteria were (1) D-TGA after neonatal arterial switch operation; (2) age 9-29 years; (3) absence of known cardiovascular risk factors such as hypertension, diabetes, hypercholesterolemia, vascular disease, recurrent vasovagal syncope, and coronary artery disease; and (4) ability to comply with overnight fasting. Exclusion criteria included (1) body mass index ≥85th percentile, (2) use of medications affecting vascular tone, or (3) acute illness. We assessed endothelial function by endothelial pulse amplitude testing and compared the results to our previously published data in healthy controls (n = 57). We tested 20 D-TGA patients (16.4 ± 4.8 years old) who have undergone arterial switch operation at a median age of 5 days (0-61 days). Endothelial pulse amplitude testing indices were similar between patients with D-TGA and controls (1.78 ± 0.61 vs. 1.73 ± 0.54, p = 0.73).In our study population of children and young adults, there was no evidence of peripheral endothelial dysfunction in patients with D-TGA who have undergone arterial switch operation. Our results support the theory that coronary arterial wall thickening and abnormal vasodilation reported in these patients is a localized phenomenon and not reflective of overall atherosclerotic burden.

Arterial stiffness and arterial function in adult cyanotic patients with congenital heart disease

BACKGROUND

Mortality in cyanotic patients with congenital heart diseases (CHD) is high, mainly due to cardiovascular complications. It is known that endothelial dysfunction, increased arterial stiffness, and impaired vascular function have negative influence on cardiovascular prognosis. The aim of the study was to assess parameters of arterial stiffness and vascular dysfunction in cyanotic patients with CHD as well as their potential relation to impaired blood oxygen saturation and polycythemia parameters typical for cyanosis.

METHODS

A total of 36 CHD cyanotic patients (17 males) (42.3±16.3 years) and 35 healthy individuals (16 males) (39.6±10.4 years) were enrolled. Assessed parameters were intima media thickness and flow-mediated dilatation (FMD). Assessed parameters using applanation tonometry methods were aortic systolic pressure, aortic pulse pressure (AoPP), augmentation pressure (AP), augmentation index (AI), pulse pressure amplification (PPampl), and pulse wave velocity (PWV).

RESULTS

AoPP (37.3±11.1mmHg vs. 29±6.5mmHg; p=0.002), AP (10.1±7.3mmHg vs. 1.1±3.9mmHg; p=0.00001), AI (24.7±13.5% vs. 3.0±13.6%; p=0.00001), and PWV (7.4±2.1m/s vs. 6.3±0.7m/s; p=0.003) were higher, and PPampl was lower (135.3±16.1% vs. 160.4±12.8%; p=0.00001) in the studied group compared to controls and proved the presence of the increased stiffness of arteries. Impairment of FMD was observed (9.0±5.6 vs. 10.9±4.7; p=0.04). No significant correlations were found between analyzed arterial parameters and biochemical ones characterizing cyanotic patients depicting rheological properties of blood.

CONCLUSIONS

Cyanotic patients with CHD are characterized by increased arterial stiffness estimated with pulse wave analysis parameters and by deteriorated arterial function expressed with worse vasodilatative response in comparison with healthy population. It may confirm relevance of those mechanisms in development of increased rate of cardiovascular events in this population. Association between oxygen saturation or polycythemia and arterial stiffening or vascular dysfunction was not found in these patients.