Asymmetric dimethylarginine and vascular indices of atherosclerosis in patients after coarctation of aorta repair

Asymmetric dimethylarginine: Is it a risk facgtor in the repair of aortic coarctation?

BACKGROUND

Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, causes endothelial dysfunction which is an important risk factor for mortality in adult cardiovascular diseases. We aimed to investigate whether there was a relationship between the aortic cross-clamping (ACC) time and serum ADMA level in aortic coarctation surgery and importance of the serum ADMA level as a marker of mortality and morbidity.

METHOD

Twenty-two patients undergoing surgery for aortic coarctation in the neonatal and early infant period were included in the study, and the patients were divided into two groups according to the aortic cross-clamping time (Group I: <20-min, Group II: >20-min).

RESULTS

In Group I, preoperative and postoperative mean ADMA values of the patients were 0.57 ± 0.78 and 0.54 ± 0.83 µmol/L, respectively. In Group II, preoperative and postoperative mean ADMA values of the patients were 0.69 ± 0.93 and 1.10 ± 0.30 µmol/L, respectively. Preoperative-postoperative change of ADMA correlates with ACC time (r = .802, p < .005) and duration of postoperative inotropic support (r = .719, p < .05). Also a high correlation has been found between the ACC time and duration of inotropic support in both groups (r = .689, p < .05).

CONCLUSION

Perioperative serum ADMA levels could be used as a prognostic bio-marker in the patients undergoing aortic coarctation repair. Treatments to reduce serum ADMA levels can be valuable for preventing mortality and morbidity which develop after surgeries in a transient ischemia setting by clamping the aorta.

Is the burden of late hypertension and cardiovascular target organ damage in children and adolescents with coarctation of the aorta after early successful repair different to healthy controls?

OBJECTIVE

Cardiovascular morbidity is high in patients with coarctation of aorta even after successful repair. This study aimed to assess the frequency of late hypertension and the relationship between ambulatory hypertension and cardiovascular target organ damage in children and adolescents after early and successful repair of coarctation of the aorta.

METHODS

Twenty-five children and adolescents (mean age 13.5 ± 3.43 years) with repaired coarctation of the aorta (median age at repair 4 months, arm-leg gradient <20 mmHg) and 16 healthy controls were included. Office and ambulatory blood pressure, pulse wave velocity, and left ventricular mass index were assessed.

RESULTS

Both day- and night-time systolic blood pressure standard deviation score and left ventricular mass index were significantly higher in patients compared to controls (p ≤ 0.001 for all), whereas pulse wave velocity did not differ. The prevalence of masked hypertension, isolated nocturnal hypertension, and left ventricular hypertrophy were 40, 28, and 24%, respectively. Left ventricular mass index was higher in patients with sustained hypertension, masked hypertension, and normotension compared to controls (p < 0.05). In multivariate analysis, higher night-time systolic blood pressure standard deviation score was the only independent predictor of left ventricular mass index.

CONCLUSION

The present study reveals a high prevalence of masked hypertension, isolated nocturnal hypertension, and left ventricular hypertrophy in children and adolescents with coarctation of the aorta even after early and successful repair. Ambulatory blood pressure monitoring should be considered to diagnose hypertension. All coarctation of aorta patients should be followed up lifelong and encouraged to establish a healthy lifestyle starting from childhood.

Impact of Treatment Modality on Vascular Function in Coarctation of the Aorta: The LOVE - COARCT Study

Background Optimally treated patients with coarctation of the aorta remain at risk for late vascular dysfunction. The effect of treatment modality on vascular function is unknown. The LOVE-COARCT (Long-term Outcomes and Vascular Evaluation After Successful Coarctation of the Aorta Treatment) study was done to compare vascular function in patients with coarctation of the aorta treated with surgery, balloon dilation (BD), or stent implantation. Methods and Results In treated coarctation of the aorta patients without residual coarctation, we prospectively compared aortic stiffness by applanation tonometry and cardiac magnetic resonance; endothelial function by endothelial pulse amplitude testing; blood pressure ( BP ) phenotype by office BP , ambulatory BP monitoring, and BP response to exercise; left ventricular mass by cardiac magnetic resonance; and blood biomarkers of endothelial function, inflammation, vascular wall function, and extracellular matrix. Participants included 75 patients treated with surgery (n=28), BD (n=23), or stent (n=24). Groups had similar age at enrollment, coarctation of the aorta severity, residual gradient, and metabolic profile, but differed by age at treatment. Prevalence of systemic hypertension, aortic stiffness, endothelial function, and left ventricular mass were similar among treatment groups. However, BD patients had more-distensible ascending aortas, lower peak systolic BP during exercise, less impairment in diurnal BP variation, and lower inflammatory biomarkers. Results were unchanged after adjustment for potential confounders, including age at treatment. Conclusions In our cohort of patients without residual coarctation, treatment modality was not associated with major vascular outcomes, even though there were some favorable vascular characteristics in the BD patients. Although this suggests that choice of treatment modality should continue to be driven by likelihood of achieving a good anatomical result, more long-term studies are required to assess the clinical significance of the more-optimal results of secondary markers of vascular function in BD patients. Clinical Trial Registration URL : http://www.clinicaltrials.gov . Unique identifier: NCT 03262753.

Rationale and design of Long-term Outcomes and Vascular Evaluation after Successful Coarctation of the Aorta Treatment study

Background:

Coarctation of the aorta (CoA) can be treated using surgery, balloon angioplasty, or stent implantation. Although short-term results are excellent with all three treatment modalities, long-term cardiovascular (CV) morbidity and mortality remain high, likely due to persistently abnormal vascular function. The effects of treatment modality on long-term vascular function remain uncharacterized. The goal of this study is to assess vascular function in this patient population for comparison among the treatment modalities.

Methods:

We will prospectively assess vascular Afunction in large and small arteries fusing multiple noninvasive modalities and compare the results among the three groups of CoA patients previously treated using surgery, balloon angioplasty, or stent implantation after frequency matching for confounding variables. A comprehensive vascular function assessment protocol has been created to be used in 7 centers. Our primary outcome is arterial stiffness measured by arterial tonometry. Inclusion and exclusion criteria have been carefully established after consideration of several potential confounders. Sample size has been calculated for the primary outcome variable.

Conclusion:

Treatment modalities for CoA may have distinct impact on large and small arterial vascular function. The results of this study will help identify the treatment modality that is associated with the most optimal level of vascular function, which, in the long term, may reduce CV risk.

Aortic stiffness and left ventricular diastolic function in children following early repair of aortic coarctation

Aortic stiffness and diastolic function are abnormal in adults with repaired coarctation of the aorta (CoA). The goal of this study was to determine the relation between aortic stiffness and left ventricular (LV) diastolic impairment in children who had undergone CoA repair very early in life. This is a retrospective review of echocardiograms in children with isolated repaired CoA (group CoA; n = 24) and healthy matched controls (group Normal; n = 24). We analyzed systolic and LV diastolic functions, proximal and distal ascending aortic stiffness indices (SIs), distensibility, and strain. Age range was 0.3 to 21 (median 9) years. Age at time of CoA repair was 0 to 24 (median 0.5) months. Median time since CoA repair was 6 years. There was no significant difference in blood pressure, LV size, and systolic function between the groups. LV diastolic function was impaired in group CoA compared with group Normal (septal E': CoA 10.3 ± 1.6 cm/s and Normal 13.4 ± 1.9 cm/s, p <0.001). All parameters of proximal and distal ascending aortic elasticities were abnormal in group CoA versus Normal (SI of proximal ascending aorta: CoA 4.9 ± 1.6 and Normal 2.7 ± 0.6, p <0.001). Across all patients, there was a strong correlation between septal E' and proximal ascending aortic SI (r = -0.72, p <0.001). In conclusion, even children who underwent CoA repair at a very young age have abnormal LV diastolic function and aortic elasticity compared with controls and there is a linear relation between the 2. LV diastolic dysfunction in patients with repaired CoA may be due to chronically increased afterload.

Computational simulations demonstrate altered wall shear stress in aortic coarctation patients treated by resection with end-to-end anastomosis

BACKGROUND

Atherosclerotic plaque in the descending thoracic aorta (dAo) is related to altered wall shear stress (WSS) for normal patients. Resection with end-to-end anastomosis (RWEA) is the gold standard for coarctation of the aorta (CoA) repair, but may lead to altered WSS indices that contribute to morbidity.

METHODS

Computational fluid dynamics (CFD) models were created from imaging and blood pressure data for control subjects and age- and gender-matched CoA patients treated by RWEA (four males, two females, 15 ± 8 years). CFD analysis incorporated downstream vascular resistance and compliance to generate blood flow velocity, time-averaged WSS (TAWSS), and oscillatory shear index (OSI) results. These indices were quantified longitudinally and circumferentially in the dAo, and several visualization methods were used to highlight regions of potential hemodynamic susceptibility.

RESULTS

The total dAo area exposed to subnormal TAWSS and OSI was similar between groups, but several statistically significant local differences were revealed. Control subjects experienced left-handed rotating patterns of TAWSS and OSI down the dAo. TAWSS was elevated in CoA patients near the site of residual narrowings and OSI was elevated distally, particularly along the left dAo wall. Differences in WSS indices between groups were negligible more than 5 dAo diameters distal to the aortic arch.

CONCLUSIONS

Localized differences in WSS indices within the dAo of CoA patients treated by RWEA suggest that plaque may form in unique locations influenced by the surgical repair. These regions can be visualized in familiar and intuitive ways allowing clinicians to track their contribution to morbidity in longitudinal studies.