Impact of valve morphology, hypertension and age on aortic wall properties in patients with coarctation: a two-centre cross-sectional study

Diagnosis and surgical outcomes of coarctation of the aorta in pediatric patients: a retrospective study

BACKGROUND

Coarctation of the aorta (CoA) is a common congenital cardiovascular malformation, and improvements in the diagnostic process for surgical decision-making are important. We sought to compare the diagnostic accuracy of transthoracic echocardiography (TTE) with computed tomographic angiography (CTA) to diagnose CoA.

METHODS

We retrospectively reviewed 197 cases of CoA diagnosed by TTE and CTA and confirmed at surgery from July 2009 to August 2019.

RESULTS

The surgical findings confirmed that 19 patients (9.6%) had isolated CoA and 178 (90.4%) had CoA combined with other congenital cardiovascular malformations. The diagnostic accuracy of CoA by CTA was significantly higher than that of TTE (χ2 = 6.52, p = 0.01). In contrast, the diagnostic accuracy of TTE for associated cardiovascular malformations of CoA was significantly higher than that of CTA (χ2 = 15.36, p < 0.0001). Infants and young children had more preductal type of CoA, and PDA was the most frequent cardiovascular lesion associated with CoA. The pressure gradient was significantly decreased after the first operation, similar at 6 months, 1 year, and 3 years follow-ups by TTE.

CONCLUSIONS

CTA is more accurate as a clinical tool for diagnosing CoA; however, TTE with color Doppler can better identify associated congenital cardiovascular malformations. Therefore, combining TTE and CTA would benefit clinical evaluation and management in patients suspected of CoA. TTE was valuable for post-operation follow-up and clinical management.

Comparison of aortic stiffness and hypertension in repaired coarctation patients with a bicuspid versus a tricuspid aortic valve

BACKGROUND

Coarctation of the aorta (COA) is associated with reduced aortic distensibility and systemic hypertension (HTN). 60-85% of COA patients have a bicuspid aortic valve (BAV). It is not known if the presence of a BAV accentuates the aortopathy and HTN in CoA patients. We examined whether patients with COA and a BAV had lower aortic distensibility by CMR, and a higher prevalence of systemic HTN compared with COA patients with a tricuspid aortic valve (TAV).

METHODS

In successfully repaired COA patients excluding those with residual COA, ascending aorta (AAO) and descending aorta (DAO) distensibility was calculated by CMR. HTN was assessed using standard pediatric and adult criteria.

RESULTS

Among 215 COA patients (median age 25.3 years), 67% had a BAV, and 33% had a TAV. Median AAO distensibility z-score was lower in the BAV group (- 1.2 versus - 0.7; p = 0.014) but DAO distensibility was similar in BAV and TAV patients. HTN prevalence was similar in BAV (32%) and TAV groups (36%, p = 0.56). On multivariable analysis controlling for confounders, HTN was not associated with BAV but was associated with male gender (p = 0.003) and older age at follow-up (p = 0.004).

CONCLUSIONS

In young adults with treated COA, those with a BAV had stiffer AAO compared to those with a TAV, but DAO stiffness was similar. HTN was not related to BAV. These results suggest that although the presence of a BAV in COA exacerbates the AAO aortopathy, it does not exacerbate the more generalized vascular dysfunction and associated HTN.

Clinical, Experimental, and Computational Validation of a New Doppler-Based Index for Coarctation Severity Assessment

BACKGROUND

Long-term morbidity including hypertension often persists in coarctation patients despite current guidelines. Coarctation severity can be invasively assessed via peak-to-peak catheter pressure gradient (PPCG), which is estimated noninvasively via simplified Bernoulli equation and conventionally reported as peak instantaneous Doppler gradient (PIDG). However, underlying simplifications of the equation limit diagnostic accuracy. We studied the diagnostic performance of a new Doppler-based diastolic index called the continuous flow pressure gradient (CFPG) versus conventional indices in assessing coarctation severity.

METHODS

In a rabbit model mimicking human aortic coarctation, temporal blood pressure waveforms revealed the diastolic instantaneous pressure gradients and spectral Doppler features impacted by coarctation severity. We therefore hypothesized that CFPG provides superior correlation with coarctation gradients measured invasively. PIDG and CFPG were quantified using color flow echocardiography in humans and rabbits with discrete coarctations. Results were compared with PPCG in rabbits (n = 34) and arm-leg systolic gradients (n = 25) in humans via 1-way analysis of variance, Pearson's correlation, linear regression, and Bland-Altman analysis.

RESULTS

A threshold of CFPG ≥ 4.6 mm Hg was identified via the Youden index as representative of PPCG ≥ 20 mm Hg (the current guideline value for coarctation intervention) in rabbits, while a CFPG ≥1.0 mm Hg represented an arm-leg systolic gradient ≥20 mm Hg in humans. Accuracy measures revealed superior correlation of CFPG (R2 > 0.80) and mild receiver operating characteristic improvement (area under the receiver operating characteristic curve, 0.94-0.95) compared with PIDG (R2 < 0.63; area under the receiver operating characteristic curve, 0.89-0.95). Inter-/intraobserver variability tested by intraclass correlation coefficient revealed measurement reliability with differences ≤8.2% and 10.7%, respectively. Computational simulations of anesthetized versus conscious hemodynamics showed parameters were minimally impacted by isoflurane inherent in the data used to derive CFPG. These results confirm the potential diagnostic accuracy of CFPG in echocardiography-based coarctation severity assessment. We are optimistic that CFPG will be useful for translation of results from preclinical studies that revisit current guidelines to limit morbidity in humans with aortic coarctation.

Aortic Elasticity and Cardiac Function in Fetuses With Aortic Coarctation

Objective

The purpose of the study was to observe the elasticity of the ascending aorta (AAo) in normal fetuses and fetuses with coarctation of the aorta (CoA) by M-mode echocardiography.

Methods

This was a prospective clinical study performed on 16 fetuses with CoA and 48 gestational-age matched normal fetuses. The minimum internal diameter in the diastolic phase (Dmin) and the maximum internal diameter in the systolic phase (Dmax) of the AAo were measured by M-mode echocardiography. The aortic strain was calculated using the formula 100 × (Dmax−Dmin)/Dmin). Doppler echocardiography was performed to measure the cardiac function parameters. Correlations between aortic strain and cardiac function were assessed in fetuses with CoA.

Results

The aortic strain of the ascending aorta in the fetuses with CoA was significantly lower than that in normal fetuses (18.12 ± 4.88% vs. 25.22 ± 4.92%, p < 0.01). The fetuses with CoA showed significantly higher combined cardiac output than the controls (471.89 ± 93.98 vs. 411.57 ± 46.35 ml/min/kg, p < 0.05). Compared with the normal group, the early diastolic velocities (E') and peak systolic velocities (S') of the left side were obviously decreased in the CoA group (p < 0.05), while the left early diastolic velocity ratio (E/E') was significantly increased in the fetuses with CoA (p < 0.01). For the fetuses with CoA, the aortic strain of the AAo was correlated with the left E/E' and S' (r = −0.522 and 0.504, respectively, P < 0.05).

Conclusions

The aortic strain of the ascending aorta was significantly decreased in fetuses with CoA in middle-late gestation. The impaired strain of the ascending aorta was correlated with the left ventricle function in the fetuses with CoA. These findings imply that the abnormalities of the intrinsic aortic wall of CoA might develop early in utero.

Challenges in diagnosis and management of coarctation of the aorta

PURPOSE OF REVIEW

Coarctation of the aorta remains a controversial topic with uncertainties in long-term outcomes.

RECENT FINDINGS

Recent advances in fetal imaging including echocardiography and MRI offer novel opportunities for better detection and prediction of the need for neonatal intervention.New imaging techniques are providing novel insights about the impact of arch geometry and size on flow dynamics and pressure gradients. The importance of arch size rather than shape for optimal hemodynamics has been identified. Long-term outcome data suggest a significant increase in mortality risk in coarctation patients beyond the third decade when compared with the general population. Hypertension is highly prevalent not only in adult patients following repair of coarctation but also in normotensive patients presenting with LV diastolic dysfunction and adverse remodelling, indicating that abnormal vascular properties are important. Patients with coarctation undergoing neonatal repair are at risk for adverse neurodevelopmental outcomes and patients could benefit from timely neurocognitive evaluation and intervention.

SUMMARY

Optimizing aortic arch size, prevention and aggressive treatment of hypertension and vascular stiffening are important to improve long-term outcomes.