Increased stiffness and persistent narrowing of the aorta after successful repair of coarctation of the aorta: relationship to left ventricular mass and blood pressure at rest and with exercise

Fontan Circulation and Aortic Stiffness: Insights into Vascular Dynamics and Haemodynamic Interplay

Increased aortic stiffness predisposes cardiac afterload and influences cardiac function. Congenital heart diseases involving aortic arch malformation and extended cardiovascular surgery, i.e. univentricular heart diseases, can lead to increased aortic stiffness. This study aimed to investigate whether Fontan patients (FO) have increased aortic stiffness within distinct aortic segments, and whether these parameters relate to Fontan-specific haemodynamics. In a prospective case-control study, 20 FO and 49 heart-transplanted control subjects with biventricular circulation underwent invasive cardiac catheterisation. We invasively measured pulse wave velocity (PWV) in the ascending aorta and along the entire aorta. Haemodynamic parameters, including end-diastolic pressure, pulmonary artery pressure, the cardiac index and systemic vascular resistance index were also assessed. FO exhibited significantly higher ascending aorta PWV (aPWV) than controls (FO: 7.2 ± 2.4 m/s|Controls: 4.9 ± 0.7 m/s, p < 0.001) and compared to the inner group central aorta PWV (cPWV; FO: 5.5 ± 1.2 m/s|Controls: 5.3 ± 1.0 m/s). Multivariate analysis confirmed this aPWV elevation in FO even after adjusting for age and BMI. aPWV and cPWV were almost identical within the control group. Correlation analyses revealed associations between cPWV and blood pressure in controls, while correlations were less apparent in FO. We detected no significant association between the aPWV and other haemodynamic parameters in any of our groups. FO exhibit increased aPWV, indicating specific vascular stiffness in the ascending aorta, while their overall aortic stiffness remains comparable to controls. Further research is needed to understand the implications of these findings on Fontan circulation and long-term cardiovascular health.

CENTRAL MESSAGE

Fontan patients show increased aortic arch pulse wave velocity, suggesting specific vascular stiffness.

PERSPECTIVE STATEMENT

Our study offers rare insights into pulse wave velocity in Fontan patients, highlighting increased arterial stiffness in the aortic arch. Vascular stiffness was particularly increased in the area of surgical reconstruction. This indicates the need for further research on vascular stiffness in Fontan circulation to understand its impact on cardiovascular health.

CLINICAL TRIAL REGISTRATION

German clinical trial registration, DRKS00015066.

Aortenisthmusstenose – eine lebenslange Systemerkrankung

Koarktation der Aorta (CoA) ist eine Systemerkrankung aller prästenotischen Arterien. Während im Säuglingsalter die chirurgische Behandlung im Vordergrund steht, werden erwachsene Patienten mit CoA oder Re-CoA nach chirurgischer Initialbehandlung, heute überwiegend mit Stents behandelt, wenn dies technisch möglich ist. Trotz erfolgreicher Beseitigung der aortalen Enge bleiben viele Patienten hypertensiv. Die Ursache des arteriellen Hypertonus ist multifaktoriell. Erwachsene CoA-Patienten müssen zum einen regelmäßig in einem EMAH-Zentrum evaluiert werden und benötigen zum anderen häufig eine permanente antihypertensive medikamentöse Therapie.

Carotid atherosclerosis, changes in tissue remodeling and repair in patients with aortic coarctation

BACKGROUND AND AIMS

After aortic coarctation (CoA) repair, patients still suffer from cardiovascular complications. The aim of this study was to measure cardiovascular markers, intima-media thickness (IMT) and plaques in controls and patients with CoA.

METHODS

Sixty-four patients with CoA (66% male, mean age 48 ± 15 years) and controls (54% men, mean age 47 ± 16 years) underwent ultrasound of their arteries. A multiplex platform to analyze circulating blood levels biomarkers reflecting inflammation, tissue remodeling and repair was used.

RESULTS

In men following CoA repair, a significantly increased carotid bulb IMT was observed in comparison to the control group (1.05 [0.72-1.24] vs. 0.67 [0.59-0.95] mm; p = 0.003). Median common carotid artery (CCA) IMT was increased in men compared to controls (0.82 [0.61-0.97] mm vs. 0.58 [0.53-0.76] mm, p < 0.003) and in women compared to controls (0.83 [0.70-0.92] vs. 0.60 [0.55-0.69], p < 0.004). CoA demonstrated an independent association with IMT in both men and women. Men with CoA were also more likely to have a plaque in their carotid arteries (p = 0.010). In women with CoA, we observed significantly lower levels of stem cell factor (SCF, p = 0.004) while in men with CoA we observed significantly lower levels of matrix metalloproteinase-3 (MMP-3, p = 0.048), tumor necrosis factor receptor 1 (TNF-R1, p = 0.032), tumor necrosis factor receptor superfamily member 10B (TRAIL-R2, p = 0.019) and monocyte chemotactic protein 1 (MCP-1, p = 0.015).

CONCLUSIONS

This is the first study to show that despite successful CoA repair, patients have more carotid atherosclerosis than can be explained by changes in tissue remodeling and repair.

Effect of Combined Ventricular-Arterial Stiffening on Exercise Hemodynamics in Adults With Repaired Coarctation of Aorta

Background

Patients with coarctation of aorta (COA) have arterial stiffening, and this is associated with impaired cardiac reserve and hypertensive systolic blood pressure (SBP) response during exercise. However, whether patients with COA have concomitant left ventricular (LV) stiffening and the potential impact of combined ventricular-arterial stiffening on exercise hemodynamics are unknown.

Methods

We studied 174 patients with repaired COA (aged 39 ± 11 years and male 103 [59%]) and 174 matched controls. Our study hypotheses are: (1) patients with COA have higher ventricular-arterial stiffness (end-systolic elastance [Ees] and arterial elastance [Ea]) as compared with controls; (2) ventricular-arterial stiffness was associated with LV stroke volume augmentation (ΔLVSV) and SBP augmentation (ΔSBP) during exercise among patients with COA.

Results

Despite similar systolic SBP, patients with COA had higher Ea (1.8 ± 0.4 vs 1.4 ± 0.4 mm Hg/mL, P < 0.001), higher Ees (2.41 ± 0.65 vs 2.17 ± 0.40 mm Hg/mL, P < 0.001), but similar Ea/Ees (0.87 ± 0.29 vs 0.83 ± 0.33, P = 0.2). ΔLVSV was 6.1 ± 1.4 mL/beat. Combined ventricular-arterial stiffness had a stronger correlation with ΔLVSV as compared with Ea alone (r = −0.53 vs r = −0.41, P = 0.006) and as compared with Ees alone (r = −0.53 vs r = −0.46, P = 0.02). ΔSBP was 48 ± 21 mm Hg. Combined ventricular-arterial stiffness had a stronger correlation with ΔSBP as compared with Ea alone (r = 0.57 vs r = 0.43, P < 0.001) and as compared with Ees alone (r = 0.57 vs r = −0.39, P < 0.001).

Conclusion

Patients with COA had combined ventricular-arterial stiffening, and this was associated with impaired cardiac reserve and hypertensive SBP response during exercise. These findings provide foundation for further studies to determine whether drugs that reduce both ventricular and arterial stiffness will improve exercise capacity and hemodynamics in this unique population.

Wave Reflection and Ventriculo-Arterial Coupling in Bicuspid Aortic Valve Patients With Repaired Aortic Coarctation

BACKGROUND

Ventriculo-arterial (VA) coupling in bicuspid aortic valve (BAV) patients can be affected by the global aortopathy characterizing BAV disease and the presence of concomitant congenital lesions such as aortic coarctation (COA). This study aimed to isolate the COA variable and use cardiovascular magnetic resonance (CMR) imaging to perform wave intensity analysis non-invasively to shed light on VA coupling changes in BAV. The primary hypothesis was that BAV patients with COA exhibit unfavorable VA coupling, and the secondary hypothesis was that BAV patients with COA exhibit increased wave speed as a marker of reduced aortic distensibility despite successful surgical correction.

METHODS

Patients were retrospectively identified from a CMR database and divided into two groups: isolated BAV and BAV associated with repaired COA. Aortic and ventricular dimensions, global longitudinal strain (GLS), and ascending aortic flow data and area were collected and used to derive wave intensity from CMR data. The main variables for the analysis included all wave magnitudes (forward compression/expansion waves, FCW and FEW, respectively, and reflected backward compression wave, BCW) and wave speed.

RESULTS

In the comparison of patients with isolated BAV and those with BAV associated with repaired COA (n = 25 in each group), no differences were observed in left ventricular ejection fraction, GLS, or ventricular volumes, whilst significant increases in FCW and FEW magnitude were noted in the BAV and repaired COA group. The FCW inversely correlated with age and aortic size. Whilst the BCW was not significantly different compared with that in patients with/without COA, its magnitude tends to increase with a lower COA index. Patients with repaired COA exhibited higher wave speed velocity. Aortic wave speed (inversely related to distensibility) was not significantly different between the two groups.

CONCLUSION

In the absence of a significant restenosis, VA coupling in patients with BAV and COA is not negatively affected compared to patients with isolated BAV. A reduction in the magnitude of the early systolic FCW was observed in patients who were older and with larger aortic diameters.

Abnormal Aortic Wall Properties in Women with Turner Syndrome

Background  Turner syndrome (TS) is associated with aortic dilatation and dissection, but the underlying process is unclear. The aim of this study was to investigate the elastic properties and composition of the aortic wall in women with TS.

Methods  In this cross-sectional study, 52 women with TS aged 35 ± 13 years (50% monosomy, 12 with bicuspid aortic valve [BAV] and 4 with coarctation) were investigated using carotid-femoral pulse wave velocity (CF-PWV) by echocardiography and ascending aortic distensibility (AAD) and aortic arch pulse wave velocity (AA-PWV) by magnetic resonance imaging (MRI). As control group, 13 women with BAV without TS and 48 healthy patients were included.

Results  Women with TS showed a higher AA-PWV (β = 1.08, confidence interval [CI]: 0.54–1.62) after correcting for age and comorbidities compared with controls. We found no significant difference in AAD and CF-PWV. In women with TS, the presence of BAV, coarctation of the aorta, or monosomy (45, X) was not associated with aortic stiffness. In addition, aortic tissue samples were investigated with routine and immunohistochemical stains in five additional women with TS who were operated. The tissue showed more compact smooth muscle cell layers with abnormal deposition and structure of elastin and diminished or absent expression of contractile proteins desmin, actin, and caldesmon, as well as the progesterone receptor.

Conclusion  Both aortic arch stiffness measurements on MRI and histomorphological changes point toward an inherent abnormal thoracic aortic wall in women with TS.

Impact of complex congenital heart disease on the prevalence of arterial hypertension after aortic coarctation repair

OBJECTIVES

This study was designed to evaluate the difference in the prevalence of long-term arterial hypertension among patients with corrected aortic coarctation according to the existence of associated cardiac congenital lesions.

METHODS

We identified 235 patients who had undergone surgery for aortic coarctation and classified them into 2 groups: patients with isolated coarctation of the aorta (CoA) and patients with aortic coarctation associated with complex congenital heart disease. Data were retrospectively analysed.

RESULTS

There were 148 subjects with isolated CoA and 87 with complex CoA (CoA-c). Patients were defined as hypertensive if they required antihypertensive treatment and/or when blood pressure was above 95th percentile. Patients with isolated aortic coarctation were significantly younger than patients with CoA-c (P < 0.001) and a markedly higher prevalence of arterial hypertension (44% vs 24%) was documented in the isolated coarctation group. The difference in the prevalence of hypertension in the 2 groups was still significant after correcting for differences in age (P < 0.001), confirming that the prevalence of arterial hypertension in patients with CoA-c was half of that of patients with isolated CoA.

CONCLUSIONS

We conclude that complex congenital heart disease in patients who have undergone surgical correction for aortic coarctation results in a significantly lower prevalence of late-onset hypertension. Reduced systemic flow and pressure before surgery in patients with CoA-c might be associated with a lower rate of arterial hypertension.

Aortic Coarctation

Aortic coarctation is a discrete narrowing of the thoracic aorta. In addition to anatomic obstruction, it can be considered an aortopathy with abnormal vascular properties characterized by stiffness and impaired relaxation. There are surgical and transcatheter techniques to address the obstruction but, despite relief, patients with aortic coarctation are at risk for hypertension, aortic complications, and abnormalities with left ventricular performance. This review covers the etiology, pathophysiology, diagnosis, and management of adults with aortic coarctation, with emphasis on multimodality imaging characteristics and lifelong surveillance to identify long-term complications.

Doppler-Derived Arterial Load Indices Better Reflect Left Ventricular Afterload Than Systolic Blood Pressure in Coarctation of Aorta

BACKGROUND

Patients with vascular stiffening may display increased arterial afterload that is out of proportion to systolic blood pressure (SBP). Since vascular and endothelial dysfunction develop in patients with coarctation of aorta (COA), we hypothesized that for any SBP, patients with mild COA (COA peak velocity <2 m/s) will have a higher arterial afterload and increased left ventricular mass index (LVMI) compared with controls, and that Doppler-derived arterial load indices would be a better predictor of LVMI compared with SBP alone.

METHODS

We studied 204 COA patients (age 35±12 y) and 204 matched controls. Doppler-derived arterial afterload was assessed using effective arterial elastance index and total arterial compliance index.

RESULTS

Despite similar SBP, the mild COA group displayed higher arterial afterload as evidenced by a higher elastance index (3.3±0.9 versus 2.9±0.7 mm Hg/mL·m2; P<0.001) and lower total arterial compliance index (0.8±0.3 versus 1.2±0.5 mL/mm Hg·m2; P<0.001). This was associated with higher LVMI in COA (109±35 versus 93±32, g/m2; P<0.001). Compared with SBP (β=0.24 [95% CI, 0.02-0.45]), elastance index (β=20.2 [95% CI, 15.8-44.1]) and total arterial compliance index (β=-32.5 [95% CI, -43.8 to -123.6]) were better predictors of LVMI. Elastance index (but not SBP) was predictive of longitudinal increases in LVMI (r=0.43, P<0.001).

CONCLUSIONS

COA patients had higher arterial afterload compared with controls with similar SBP. In comparison to SBP, Doppler-derived arterial load indices correlate more strongly with LV hypertrophy. These data suggest that SBP may underestimate LV afterload in this population. This has important clinical implications since titration of antihypertensive therapy is currently based on SBP.

Mild Coarctation of Aorta is an Independent Risk Factor for Exercise-Induced Hypertension

Exercise-induced hypertension is a predictor of cardiovascular events in patients with coarctation of aorta (COA). However, it is unclear whether mild COA diagnosis is an independent risk factor of exercise-induced hypertension. We hypothesized that for every unit increase in exercise, patients with COA (without hemodynamically significant coarctation) will have a higher rise in systolic blood pressure (SBP) compared with matched controls. One hundred forty-nine patients with COA (aortic coarctation peak velocity <2 m/s) who underwent exercise testing were matched 1:1 to controls using propensity score method based on age, sex, body mass index, hypertension diagnosis, and SBP at rest. We compared exercise-induced change in SBP between patients with COA and controls and also assessed the correlation between Doppler-derived aortic vascular function indices (effective arterial elastance index and total arterial compliance index) and exercise-induced changes in SBP. Compared with controls, patients with COA had a greater change in SBP per unit metabolic equivalent (β=2.86; 95% CI, 1.96–4.77 versus 1.07, 95% CI, −0.15 to 1.75; P =0.018) and per unit oxygen pulse (β=4.57; 95% CI, 2.97–7.12 versus 1.45, 95% CI, −0.79 to 2.09, P <0.001). There was a correlation between SBP peak −SBP rest and elastance index ( r =0.38, P =0.032) and between SBP peak −SBP rest and total arterial compliance index ( r =−0.51, P =0.001), suggesting an association between vascular dysfunction and exercise-induced BP changes. Patients with COA, without significant obstruction, had higher exercise-induced changes in SBP after adjustment for other risk factors for hypertension. Considering the already known prognostic importance of exercise-induced hypertension, the current study highlights the potential role of exercise testing for risk stratification of patients with mild COA.

Repaired coarctation of the aorta, persistent arterial hypertension and the selfish brain

BACKGROUND

It has been estimated that 20-30% of repaired aortic coarctation (CoA) patients develop hypertension, with significant cardiovascular morbidity and mortality. Vertebral artery hypoplasia (VAH) with an incomplete posterior circle of Willis (ipCoW; VAH + ipCoW) is associated with increased cerebrovascular resistance before the onset of increased sympathetic nerve activity in borderline hypertensive humans, suggesting brainstem hypoperfusion may evoke hypertension to maintain cerebral blood flow: the "selfish brain" hypothesis. We now assess the "selfish brain" in hypertension post-CoA repair.

METHODS

Time-of-flight cardiovascular magnetic resonance angiography from 127 repaired CoA patients (34 ± 14 years, 61% male, systolic blood pressure (SBP) 138 ± 19 mmHg, diastolic blood pressure (DBP) 76 ± 11 mmHg) was compared with 33 normotensive controls (42 ± 14 years, 48% male, SBP 124 ± 10 mmHg, DBP 76 ± 8 mmHg). VAH was defined as < 2 mm and ipCoW as hypoplasia of one or both posterior communicating arteries.

RESULTS

VAH + ipCoW was more prevalent in repaired CoA than controls (odds ratio: 5.8 [1.6-20.8], p = 0.007), after controlling for age, sex and body mass index (BMI). VAH + ipCoW was an independent predictor of hypertension (odds ratio: 2.5 [1.2-5.2], p = 0.017), after controlling for age, gender and BMI. Repaired CoA subjects with VAH + ipCoW were more likely to have difficult to treat hypertension (odds ratio: 3.3 [1.01-10.7], p = 0.049). Neither age at time of CoA repair nor any specific repair type were significant predictors of VAH + ipCoW in univariate regression analysis.

CONCLUSIONS

VAH + ipCoW predicts arterial hypertension and difficult to treat hypertension in repaired CoA. It is unrelated to age at time of repair or repair type. CoA appears to be a marker of wider congenital cerebrovascular problems. Understanding the "selfish brain" in post-CoA repair may help guide management.

JOURNAL SUBJECT CODES

High Blood Pressure; Hypertension; Magnetic Resonance Imaging (MRI); Cardiovascular Surgery; Cerebrovascular Malformations.

Echocardiography during submaximal isometric exercise in children with repaired coarctation of the aorta compared with controls

Objective

Patients with repaired coarctation (RCoA) remain at higher risk of cardiac dysfunction, initially often only detected during exercise. In this study, haemodynamics of isometric handgrip (HG) and bicycle ergometry (BE) were compared in patients with RCoA and matched controls (MCs).

Methods

Case–control study of 19 children with RCoA (mean age 12.9±2.3 years; mean age of repair 7 months) compared with 20 MC. HG with echocardiography followed by BE was performed in both groups.

Results

During HG (blood pressure) BP increased from 114±11/64±4 mm Hg to 132±14/79±7 mm Hg, without significant differences. During HG as well as BE, HR increased less in patients with RCoA. There were no significant differences in (left ventricle) LV dimensions or LV mass.

The RCoA group had diastolic dysfunction: both at rest and during HG they had significantly higher transmitral E and A velocities and lower tissue Doppler E′ and A′ velocities. E/E′ was higher, reaching statistical significance during HG (p<0001).

Conventional parameters of systolic function (FS and EF) were similar at rest and HG. More sensitive tissue Doppler S′ was significantly lower at rest in CoA subjects (5.1±1.5 cm/s vs 6.5±1±1 cm/s; p<0.01), decreasing further during HG by 5% in the CoA group (NS) while unchanged in controls.

Conclusions

We provide first evidence that HG with echocardiography is feasible, easy and patient-friendly. A decreased systolic (tissue Doppler) and impaired diastolic LV function was measured in the RCoA group, a difference that tended to increase during HG.

Relationship of Aortic Stiffness to Exercise and Ventricular Volumes in Single Ventricles

BACKGROUND

Patients with single ventricle (SV) may often undergo aortic reconstruction that creates a stiff large vessel, increasing afterload and affecting exercise performance. The objective of this study was to determine the relationship of pulse wave velocity (PWV) and distensibility in reconstructed and normal aortic arches after Fontan with exercise variables.

METHODS

PWV and distensibility of the descending aorta at the level of the diaphragm (DAo) were calculated with real-time exercise cardiac magnetic resonance in 48 patients with SV after Fontan (18 after aortic reconstruction; 30 without aortic reconstruction) and compared with metabolic exercise stress test variables.

RESULTS

PWV was greater in the reconstructed group than in the non-reconstructed group (median 4.4 m/s [range: 2.3 to 9.8 m/s] versus 3.6 [range: 2.6 to 6.3 m/s], respectively, p = 0.003). Statistically significant inverse correlations were found between PWV and end-diastolic, end-systolic, and stroke volumes at rest and at exercise in the reconstructed group. In addition, inverse correlations also existed in the reconstructed group between distensibility of the DAo and the exercise variables such as peak oxygen pulse (R = 0.56, p = 0.02), peak oxygen consumption (R = 0.63, p = 0.008), oxygen consumption at ventilatory anaerobic threshold (R = 0.48, p = 0.04), and peak work (R = 0.54, p = 0.02). Similar correlations were not seen in patients with non-reconstructed aortas.

CONCLUSIONS

Patients with SV with reconstructed aortas have increased aortic stiffness, increasing afterload on the ventricle. Native DAo stiffness distal to the reconstruction is inversely correlated with exercise performance, presumably to decrease impedance mismatch to maintain homogeneity of the aortic wall. This information suggests a possible mechanism for decreased exercise performance in patients with SV with aortic reconstructions.

Mechanical and structural analysis of the pulmonary valve in congenital heart defects: A presentation of two case studies

OBJECTIVE

Congenital Heart Disease (CHD) is the leading cause of pediatric mortality, with many cases affecting the right ventricular outflow tract (RVOT) or pulmonary valve (PV). Understanding the mechanics of the disease condition can provide insight into development of durable repair techniques and bioengineered replacement devices. This work presents a mechanical and structural analysis of the pulmonary valve of two pediatric cases.

METHODS

Two PV tissues were excised as part of the operative procedure. One PV was obtained from a 9-month-old with Noonan syndrome (Patient 1) and the other from a 6-month-old with tricuspid atresia (Patient 2). The leaflets were subjected to planar biaxial tensile testing and second harmonic generation (SHG) imaging for mechanical and structural evaluation.

RESULTS AND DISCUSSION

Patient 1 exhibited a more anisotropic mechanical response than Patient 2, with sample stiffness on par with that of adult PV tissue. Additionally, both samples showed radial and circumferential alignment of collagen fibers on the ventricularis and fibrosa sides of the leaflets, respectively. Collagen fibers on the fibrosa side were also more crimped than on the ventricularis side.

Hypertension in Coarctation of the Aorta: Challenges in Diagnosis in Children

Evidence indicates that patients with coarctation of the aorta (COA) suffer from increased cardiovascular morbidity and mortality in later life despite successful repair of COA in childhood. Systolic arterial hypertension is common, presenting in up to one-third of patients, and is regarded as the main driver of premature cardiovascular events in this group of patients. In this review, we discuss the prevalence and pathophysiology of hypertension in children following successful COA repair with no residual arch obstruction. The challenges in accurate blood pressure assessment at this early phase are considered and non-invasive measures of central blood pressure are discussed. Although the pathways for investigations in adults are well defined, we highlight the need to address the issues of cardiovascular surveillance in children and describe techniques which can provide complementary information for cardiovascular assessment in this group of patients such that timely treatment can occur.

Aortic stenting in the growing sheep causes aortic endothelial dysfunction but not hypertension: Clinical implications for coarctation repair

BACKGROUND

Stent implantation is the treatment of choice for adolescents and adults with aortic coarctation (CoAo). Despite excellent short-term results, 20%-40% of the patients develop arterial hypertension later in life, which was attributed to inappropriate response of the aortic baroreceptors to increased stiffness of the ascending aorta (ASAO), either congenital or induced by CoAo repair. In particular, it has been hypothesized that stent itself may cause or sustain hypertension. Therefore, we aimed to study the hemodynamic and structural impact following stent implantation in the normal aorta of a growing animal.

METHODS

Eight female sheep completed the study and a stent was implanted in four. Every 3 mo we measured blood pressure of the anterior and posterior limbs and left ventricular function by echocardiography. Twelve months later invasive pressure was measured under baseline and simulated stress conditions. Expression of genes indicating oxidative stress (OS), endothelial dysfunction (ED) and stiffness, as well as pathological examination were performed in ascending (ASAO) and descending aorta (DSAO).

RESULTS

SOD1 and MMP9 gene expression were higher in ASAO of the stented animals, compared to DSAO and controls, while NOS3 was decreased. No differences were found in blood pressure and echocardiographic parameters. No histological differences were found in the aorta of the two groups of animals.

CONCLUSIONS

Stent does not affect central and peripheral hemodynamics, cardiac structure and function even in the long term. However, the finding of markers of OS and increased stiffness of ASAO, proximal to the stent, points to molecular mechanisms for increased cardiovascular risk of patients with stented CoAo.

Noninvasive pressure difference mapping derived from 4D flow MRI in patients with unrepaired and repaired aortic coarctation

PURPOSE

To develop a method for computing and visualizing pressure differences derived from time-resolved velocity-encoded three-dimensional phase-contrast magnetic resonance imaging (4D flow MRI) and to compare pressure difference maps of patients with unrepaired and repaired aortic coarctation to young healthy volunteers.

METHODS

4D flow MRI data of four patients with aortic coarctation either before or after repair (mean age 17 years, age range 3-28, one female, three males) and four young healthy volunteers without history of cardiovascular disease (mean age 24 years, age range 20-27, one female, three males) was acquired using a 1.5-T clinical MR scanner. Image analysis was performed with in-house developed image processing software. Relative pressures were computed based on the Navier-Stokes equation.

RESULTS

A standardized method for intuitive visualization of pressure difference maps was developed and successfully applied to all included patients and volunteers. Young healthy volunteers exhibited smooth and regular distribution of relative pressures in the thoracic aorta at mid systole with very similar distribution in all analyzed volunteers. Patients demonstrated disturbed pressures compared to volunteers. Changes included a pressure drop at the aortic isthmus in all patients, increased relative pressures in the aortic arch in patients with residual narrowing after repair, and increased relative pressures in the descending aorta in a patient after patch aortoplasty.

CONCLUSIONS

Pressure difference maps derived from 4D flow MRI can depict alterations of spatial pressure distribution in patients with repaired and unrepaired aortic coarctation. The technique might allow identifying pathophysiological conditions underlying complications after aortic coarctation repair.

Obesity and elevated blood pressure following repair of coarctation of the aorta

OBJECTIVE

To determine whether patients with coarctation of the aorta (COA) were more likely to develop obesity compared with the general population or others with isolated forms of congenital heart disease.

STUDY DESIGN

We conducted a cross-sectional study of 160 patients who underwent COA repair at our institution between 1974 and 2009. Body mass index (BMI) measurements were obtained from the most recent clinic visit and at 5, 10, 15, and 20 years of age from retrospective chart review. BMI values were compared against established normal data to obtain age-sex matched z-scores. We also compared the rates of developing obesity over time in adults with COA vs 96 adults with other isolated forms of congenital heart disease, including aortic valve stenosis, pulmonary valve stenosis, or atrial septal defect.

RESULTS

After age 5 years, patients with COA had significantly greater BMI z-scores compared with age-sex matched normal data (P < .001). The proportion of obesity in patients with COA significantly increased over time (P < .001). Adults with repaired COA developed obesity at a greater rate than those with either aortic valve stenosis (P = .004) or with pulmonary valve stenosis or atrial septal defect (P < .001).

CONCLUSIONS

There is a greater incidence of obesity that progressively increases with age in patients with repaired COA. Adults with repaired COA developed obesity at a greater rate than those with other isolated forms of congenital heart disease. Further prospective trials are needed to confirm our observations and to elucidate the potential mechanism relating COA to obesity.

Coarctation of the aorta: lifelong surveillance is mandatory following surgical repair

OBJECTIVES

The objective of our study was to review the long-term outcomes of patients undergoing surgical repair of aortic coarctation.

BACKGROUND

Surgical repair of aortic coarctation has been performed at the Mayo Clinic, Rochester, Minnesota, for over 60 years.

METHODS

Between 1946 and 2005, 819 patients with isolated coarctation of the aorta underwent primary operative repair. Medical records were reviewed and questionnaires mailed to the patients.

RESULTS

Mean age at repair was 17.2 ± 13.6 years. The majority (83%) had pre-operative hypertension. Operations included simple and extended end-to-end anastomosis (n = 632), patch angioplasty (n = 72), interposition grafting (n = 49), bypass grafting (n = 30), and subclavian flap or "other" (n = 35). Overall early mortality (<30 days) was 2.4%. In the previous 30 years (n = 225), there were no operative deaths. Mean follow-up was 17.4 ± 13.9 years, with a maximum of 59.3 years. Actuarial survival rates were 93.3%, 86.4%, and 73.5% at 10, 20, and 30 years, respectively. When compared to an age- and sex-matched population, long-term survival was decreased (p < 0.001). Older age at repair (>20 yrs) and pre-operative hypertension were associated with decreased survival (p < 0.001). Patients age <9 years age at repair had significantly less hypertension at 5 to 15 years of follow-up (p < 0.001). Rates of freedom from re-intervention on the descending aorta were 96.7%, 92.2%, and 89.4% at 10, 20, and 30 years, respectively. Younger age at time of repair (p < 0.001) and an end-to-end anastomosis technique (p < 0.001) were independently associated with lower rates of re-intervention on the descending aorta.

CONCLUSIONS

Primary repair of isolated coarctation of the aorta was performed with a low rate of mortality. However, long-term survival was reduced compared with that in an age- and sex-matched population, and many patients required further reoperation. These findings emphasize that patients with aortic coarctation need early recognition and intervention, as well as lifelong informed follow-up.

Altered hemodynamics, endothelial function, and protein expression occur with aortic coarctation and persist after repair

Coarctation of the aorta (CoA) is associated with substantial morbidity despite treatment. Mechanically induced structural and functional vascular changes are implicated; however, their relationship with smooth muscle (SM) phenotypic expression is not fully understood. Using a clinically representative rabbit model of CoA and correction, we quantified mechanical alterations from a 20-mmHg blood pressure (BP) gradient in the thoracic aorta and related the expression of key SM contractile and focal adhesion proteins with remodeling, relaxation, and stiffness. Systolic and mean BP were elevated for CoA rabbits compared with controls leading to remodeling, stiffening, an altered force response, and endothelial dysfunction both proximally and distally. The proximal changes persisted for corrected rabbits despite >12 wk of normal BP (~4 human years). Computational fluid dynamic simulations revealed reduced wall shear stress (WSS) proximally in CoA compared with control and corrected rabbits. Distally, WSS was markedly increased in CoA rabbits due to a stenotic velocity jet, which has persistent effects as WSS was significantly reduced in corrected rabbits. Immunohistochemistry revealed significantly increased nonmuscle myosin and reduced SM myosin heavy chain expression in the proximal arteries of CoA and corrected rabbits but no differences in SM α-actin, talin, or fibronectin. These findings indicate that CoA can cause alterations in the SM phenotype contributing to structural and functional changes in the proximal arteries that accompany the mechanical stimuli of elevated BP and altered WSS. Importantly, these changes are not reversed upon BP correction and may serve as markers of disease severity, which explains the persistent morbidity observed in CoA patients.

Computational simulations for aortic coarctation: representative results from a sampling of patients

Treatments for coarctation of the aorta (CoA) can alleviate blood pressure (BP) gradients (Δ), but long-term morbidity still exists that can be explained by altered indices of hemodynamics and biomechanics. We introduce a technique to increase our understanding of these indices for CoA under resting and nonresting conditions, quantify their contribution to morbidity, and evaluate treatment options. Patient-specific computational fluid dynamics (CFD) models were created from imaging and BP data for one normal and four CoA patients (moderate native CoA: Δ12 mmHg, severe native CoA: Δ25 mmHg and postoperative end-to-end and end-to-side patients: Δ0 mmHg). Simulations incorporated vessel deformation, downstream vascular resistance and compliance. Indices including cyclic strain, time-averaged wall shear stress (TAWSS), and oscillatory shear index (OSI) were quantified. Simulations replicated resting BP and blood flow data. BP during simulated exercise for the normal patient matched reported values. Greatest exercise-induced increases in systolic BP and mean and peak ΔBP occurred for the moderate native CoA patient (SBP: 115 to 154 mmHg; mean and peak ΔBP: 31 and 73 mmHg). Cyclic strain was elevated proximal to the coarctation for native CoA patients, but reduced throughout the aorta after treatment. A greater percentage of vessels was exposed to subnormal TAWSS or elevated OSI for CoA patients. Local patterns of these indices reported to correlate with atherosclerosis in normal patients were accentuated by CoA. These results apply CFD to a range of CoA patients for the first time and provide the foundation for future progress in this area.

Exercise capacity after coarctation repair relates to the c.46A > G genomic polymorphism of the ss2-adrenoreceptor and the c.704T > C angiotensinogen polymorphism

BACKGROUND

Even after excellent repair of aortic coarctation without restenosis there are limitations in exercise capacity at long-term follow-up. This study was performed to assess the contribution of inherited genomic polymorphisms to exercise capacity in patients without restenosis.

PATIENTS AND METHODS

122 patients aged 17-72 years, 46 female, 76 male, seen 2-27 years after repair of aortic coarctation with a residual brachial-ankle-gradient ≤20 mmHg were investigated. Genomic polymorphism of angiotensin converting enzyme (ACE I/D), angiotensinogen (AGT, c.704C > T), angiotensin II receptor type 1 (AGTR1, c.1166A > C), endothelin 1 (EDN1, EDN1/ex5-c.5665G > T), G protein (GNB3, c.825C > T), and two polymorphisms each of the ß1-adrenoreceptor (ADRB1, c.145G > A and c.1165C > G), ß2-adrenoreceptor (ADRB2, c.46A > G and c.79C > G), and endothelial NO synthase (NOS3, intron 4 I/D and NOS3, c.894G > T) were determined by PCR amplification and fragment length analysis. Exercise capacity was determined by an upright bicycle exercise test.

RESULTS

Only the c.46A > G polymorphism of the ADRB2 (p = 0.024) and the c.704T > C AGT polymorphism (p = 0.042) were positively correlated with peak workload. Patients with one or especially two polymorphic alleles showed a significant higher exercise performance compared with those patients homozygous for the wild type.

CONCLUSIONS

In contrast to a previous study in heart failure patients, after coarctation repair adults had a better exercise capacity with the G allele of the ß2-receptor c.46A > G polymorphism. Therefore, the exercise capacity of coarctation patients does not profit from an enhanced down regulation of their beta receptors.

Neurohormonal activity and vascular properties late after aortic coarctation repair

BACKGROUND

Coarctation of aorta (CoA) patients present cardiovascular complications late after repair the causes of which are not fully understood. Our study investigates the neurohormonal and immune activation and the elastic properties of the aorta and peripheral vessels in adult patients with coarctation of aorta (CoA), late after repair.

METHODS

Nineteen adult patients with repaired CoA and 29 matched healthy controls underwent aortic distensibility, stiffness index, a study of the elastic properties of peripheral vessels proximal to the coarctation site and measurement of plasma cytokine and neurohormone levels.

RESULTS

Distensibility index was reduced (p=0.02) and stiffness index was increased (p=0.005) in CoA patients compared to control. Augmentation index (p=0.0007) and augmented pressure (p=0.001) were higher in CoA patients and Forearm Blood Flow (FBF) index was reduced (p=0.009). Plasma levels of sICAM-1 (p=0.01), sVCAM-1 (p=0.05), E-selectin (p=0.01), sFas-ligand (p=0.02) and IL-10 (p=0.01) were also elevated in CoA patients vs control. TNF-a, IL-6, Endothelin-1 and NT-pro-BNP levels were not.

CONCLUSIONS

Adults with repaired CoA seem to develop a late inflammatory reaction, which reflects a functional problem in all vessels, regardless of the initial lesion. This may explain the late complications of the disease despite early repair and improved surgical procedures.

Computational fluid dynamic simulations of aortic coarctation comparing the effects of surgical- and stent-based treatments on aortic compliance and ventricular workload

OBJECTIVES

In this work, we examine the effects of stent-induced aortic stiffness on cardiac workload and blood pressure using computational fluid dynamic simulations.

BACKGROUND

Treatment of aortic coarctation (CoA) consists of either open, surgical repair or angioplasty with or without stenting. Although stenting is a minimally invasive alternative to surgery, aortic stiffness increases in the stented section. Concern over this increased stiffness has long been argued to be detrimental to the overall vascular health of the patient.

METHODS

MR imaging was performed on a 15-year-old female with CoA. A 3D model of the large thoracic arteries was created, and the heart and downstream vasculature were represented by lumped parameter models at the model inlet and outlets, respectively. A deformable wall assumption was used in conjunction with variable wall properties and tissue support, and 3D velocity, pressure, and wall dynamics were computed. The lumped parameter values and wall properties were tuned to match the mean flow and aortic deformation as measured by MRI. The CoA was then virtually removed from the model representing an end-to-end surgical correction. In a second model, the repaired section was prescribed to be nearly rigid, representing stenting. All other variables remained the same.

RESULTS

When compared to surgery, stenting resulted in clinically negligible increases in cardiac work (0.4%) and no change in mean blood pressure.

CONCLUSIONS

This pilot study suggests CoA stenting may not affect cardiac work to any significant degree as is commonly believed in the clinical community.

Vascular remodeling in adults after coarctation repair: impact of descending aorta stenosis and age at surgery

Background

Patients after successful repair of coarctation of aorta (CoAo) are at risk of hypertension at rest and associated end-organ damage. The aim of the study was to assess arterial stiffness and function in adults after coarctation repair in relation to descending aorta (AoD) residual coarctation and patient’s age at operation.

Methods

85 patients after CoAo repair (53 males) aged 34.6 ± 10.3 years; median age at operation 0.9 ± 8.2 years. The control group—30 individuals (18 males) at mean age 33.6 ± 8.2 years. The following central parameters: augmentation pressure (AP) and augmentation index (AI) as well as peripheral vascular parameters: flow-mediated dilatation (FMD), nitroglycerin-mediated vasodilatation (NMD), intima-media thickness (IMT) and pulse wave velocity (PWV) were measured.

Results

47 CoAo-repaired patients were normotensive, and compared to control, they presented higher values of central parameters AP (7.3 ± 4.6 vs. 4.4 ± 3.6 mmHg; p = 0.002) and AI (18.6 ± 10.4 vs. 13.5 ± 4.3%; p = 0.03); as well as the increased PWV (6.8 ± 1.2 vs. 5.4 ± 0.9 m/s; p = 0.003), while IMT was comparable (0.53 ± 0.01 vs. 0.51 ± 0.01 mm; p = 0.06). The vasodilatation was impaired in the normotensive patients: FMD (4.8 ± 2.8 vs. 8.5 ± 2.3%; p = 0.00003) and NMD (11.3 ± 4.6 vs. 19.8 ± 7.2%; p = 0.00001). The comparison of recoarctation (46, 54%) to non-recoarctation (39, 46%) patients did not reveal any significant differences in resting systolic and diastolic pressures, as well as the values of AI and the peripheral vascular parameters; the value of AP was higher in the recoarctation patients (10.5 ± 6.9 vs. 7.5 ± 4.1; p = 0.02) and correlated positively with the gradient across AoD (r = 0.295, p = 0.01). There was no significant linear correlation between age at the time of surgery and any of peripheral arterial parameters.

Conclusions

Residual stenosis in AoD does not affect the arterial vasodilatation nor stiffness in patients after CoAo repair. Early operation has no impact on peripheral vascular remodeling or central pressure which supports the claim that coarctation of the aorta is a systemic vascular disorder which leads to progressive vascular and end-organ damage despite early correction.

AORTIC COARCTATION: RECENT DEVELOPMENTS IN EXPERIMENTAL AND COMPUTATIONAL METHODS TO ASSESS TREATMENTS FOR THIS SIMPLE CONDITION

Coarctation of the aorta (CoA) is often considered a relatively simple disease, but long-term outcomes suggest otherwise as life expectancies are decades less than in the average population and substantial morbidity often exists. What follows is an expanded version of collective work conducted by the authors' and numerous collaborators that was presented at the 1st International Conference on Computational Simulation in Congenital Heart Disease pertaining to recent advances for CoA. The work begins by focusing on what is known about blood flow, pressure and indices of wall shear stress (WSS) in patients with normal vascular anatomy from both clinical imaging and the use of computational fluid dynamics (CFD) techniques. Hemodynamic alterations observed in CFD studies from untreated CoA patients and those undergoing surgical or interventional treatment are subsequently discussed. The impact of surgical approach, stent design and valve morphology are also presented for these patient populations. Finally, recent work from a representative experimental animal model of CoA that may offer insight into proposed mechanisms of long-term morbidity in CoA is presented.

Impact of genomic polymorphism on arterial hypertension after aortic coarctation repair

OBJECTIVE

Even after repair of aortic coarctation without restenosis there is a high incidence of arterial hypertension. This study was performed to assess the contribution of several inherited gene polymorphisms, which are known to be related to essential hypertension.

PATIENTS AND METHODS

122 patients aged 17-72 years, 46 women, and 2-27 years after repair of isolated aortic coarctation without restenosis were investigated. Genomic polymorphism of angiotensin converting enzyme (ACE I/D), angiotensinogen (AGT, c.704C>T), angiotensin II receptor type 1 (AGTR1, c.1166A>C), aldosterone synthase (CYP11B2, c.-344C>T), endothelin 1 (EDN1, EDN1/ex5-c.5665G>T), G protein (GNB3, c.825C>T), G protein-coupled receptor kinase 4 (GRK4, c.679C>T), fibrillin 1 (FBN1, VNTR(TAAA)) and two polymorphisms each of the ß1 adrenoreceptor (ADRB1, c.145G>A and c.1165C>G), ß2 adrenoreceptor (ADRB2, c.46A>G and c.79C>G), and endothelial NO synthase (NOS3, intron 4 I/D and NOS3, c.894G>T) were determined by PCR amplification and fragment length analysis. Patients were classified "normotensive", if they were not on antihypertensive drugs and showed normal blood pressure both on ambulatory measurement and exercise test.

RESULTS

None of the investigated genomic polymorphism could be related to hypertension. Only patients with the ACE I/I genotype had a less pronounced nocturnal dipping and patients with a ADRB1 c.1165 C/C genotype had a higher systolic and mean blood pressure at night.

CONCLUSIONS

Development of late hypertension after aortic coarctation repair could not be related to the investigated genomic polymorphism. The correlation of the ACE I/D and the ADRB1 c.1165C>G polymorphism to nocturnal dipping and blood pressure at nighttime needs further confirmation.

Mid-term results, and therapeutic management, for patients suffering hypertension after surgical repair of aortic coarctation

We designed our study to investigate the efficacy of a new therapeutic approach to late onset hypertension in patients after surgical repair of aortic coarctation. Several studies have shown a higher incidence of hypertension during daily activities, and during exercise, in patients after surgical correction of coarctation. To the best of our knowledge, however, no data exists concerning haemodynamics, the response of arterial pressures, and the effects of medications for lowering blood pressure during exercise or during daily activities.We studied 128 patients, aged 15.6 +/- 4.3 years, to determine the response of blood pressure as we administered treatment in the attempt to achieve a normotensive state. We excluded patient with associated cardiac abnormalities, apart from those with bicuspid aortic valves. We evaluated blood pressure at rest in both the right arm and leg to establish presence of any gradient, as well as the blood pressure in the arm during exercise testing, and by 24-hour ambulatory monitoring.Atenolol was prescribed for those with elevated values of blood pressure but with a normal increment of heart rate during exercise. We prescribed Candesartan for those with elevated levels of blood pressure but with reduced increments of heart rate, specifically maximal heart rates of less than 85% of their predicted value. Both drugs were used when one alone was not effective. We found that, in young patients, candesartan provided better control of blood pressure with no side-effects, especially as demonstrated using 24-hour ambulatory monitoring, while atenolol was less effective, with more side-effects. Our experience suggests that both drugs should be used in patients who are non-responsive to monotherapy.

The influence of different surgical approaches on arterial rigidity in children after aortic coarctation repair

Complications, such as recoarctation or secondary hypertension, probably related to the loss of arterial elasticity, frequently occur after aortic coarctation surgery. This study aimed to investigate arterial compliance as evaluated by automated recording of the QKd interval in patients who underwent repair of coarctation by construction of a subclavian flap compared with those who underwent resection of the narrowed aortic segment with end-to-end anastomosis. Thirty-nine children who underwent surgical repair of aortic coarctation by subclavian flap (n = 19) and by end-to-end anastomosis (n = 20) were enrolled. Arterial stiffness was measured by the noninvasive QKd 100-60 method. Twenty-four-hour ambulatory blood pressure monitoring and a transthoracic echocardiography were also performed. The group of patients who had an end-to-end anastomosis showed better results regarding 24-hour blood pressure profile and QKD 100-60 value compared with those underwent construction of a subclavian flap. Surgical repair of aortic obstruction by end-to-end anastomosis demonstrates better preservation of arterial distensibility than those repaired by subclavian flap. Therefore, it appears to be advantageous, whenever possible, to use the end-end anastomosis approach, which appears to lessen the incidence of the most common complications after aortic arch surgery.

Impaired elastic properties of the ascending aorta persist within the first 3 years after neonatal coarctation repair

Abnormal elastic properties of the ascending aorta in patients with coarctation of the aorta (CoA) are already present in neonates before and after successful repair. To prove the midterm outcome for vascular pathology, a cohort of 15 patients was prospectively reevaluated. In this study, 15 patients after neonatal CoA repair (study group) and 15 healthy normal children (control group) were examined (mean age, 3.0 +/- 1.0 years). The aortic wall stiffness index and distensibility were calculated using ascending and abdominal aortic M-mode diameters and noninvasive estimation of pulse pressure. The study group was compared with the control group and with its own previously obtained pre- and postoperative measurements. After a mean follow-up period of 2.9 +/- 0.9 years, the elastic properties of the ascending aorta remained impaired in the study group compared with the control group (distensibility: 62 +/- 28 vs 94 +/- 34; p = 0.01; stiffness index: 4.4 +/- 1.9 vs 2.7 +/- 1.0; p = 0.008). At follow-up evaluation, the elasticity of the ascending aorta in the study group showed no change from the initial neonatal findings (distensibility: 63 +/- 24 vs 62 +/- 28; p = 0.82; stiffness index: 4.0 +/- 1.6 vs 4.4 +/- 1.9; p = 0.65). In both groups, descending aortic elasticity increased during the follow-up period. Our data suggest that the diminished elastic properties of the prestenotic arteries remain unchanged years after successful CoA repair. Comparisons with the neonatal data showed no evidence for remodeling of the ascending aorta in this group.

Ventricular–Vascular Stiffening in Patients With Repaired Coarctation of Aorta

Background— Despite successful repair, patients with coarctation of the aorta (COA) often show persistent hypertension at rest and/or during exercise. Previous studies indicated that the hypertension is mainly due to abnormalities in the arterial bed and its regulatory systems. We hypothesized that ventricular systolic stiffness also contributes to the hypertensive state in these patients in addition to increased vascular stiffness.

Methods and Results— The study involved 43 patients with successfully repaired COA and 45 age-matched control subjects. Ventricular systolic stiffness (end systolic elastance) and arterial stiffness (effective arterial elastance) were measured invasively by ventricular pressure–area relationship during varying preload before and after β-adrenergic stimulation. The mean systolic blood pressure was significantly higher with concomitant increases in both end systolic elastance and effective arterial elastance in patients with COA compared with control subjects (113.2±16.8 versus 91.0±9.1 mm Hg, 44.5±17.0 versus 19.2±6.7 mm Hg/mL/m 2 , and 27.8±11.4 versus 20.2±4.8 mm Hg/mL/m 2 , respectively; P <0.01 for each). End systolic elastance and effective arterial elastance of patients with COA showed exaggerated responses to β-adrenergic stimulation, further amplifying blood pressure elevation. Quantification analyses assuming that ventricular systolic stiffness of patients with COA is equal to that of the control revealed that ventricular systolic stiffness accounts for approximately 50% to 70% of the elevated blood pressure in patients with COA. Furthermore, combined ventricular–arterial stiffening amplified systolic pressure sensitivity to increased preload during abdominal compression and limited stroke volume gain/relaxation improvement induced by β-adrenergic stimulation.

Conclusions— Increased ventricular systolic stiffness, coupled with increased arterial stiffness, plays important roles in hypertension in patients with repaired COA. Thus, ventricular systolic stiffness is a potentially suitable target for reduction of blood pressure and improvement of prognosis of patients with COA.

Comparison of arterial waves derived by classical wave separation and wave intensity analysis in a model of aortic coarctation

Coarctation of the aorta may develop during fetal life and impair quality of life in the adult because upper body hypertension and aneurysm formation in the descending aorta may develop. We used our computational model of the young adult arterial circulation, incorporated aorta coarctation over a range from 0 to 80% and evaluated the effects in terms of forward pressure (P(+)) and backward pressure (P(-)). Predictions at several sites proximal and distal to the coarctation using an impedance-based waveform separation method (WSA) and the time-domain technique of wave intensity analysis (WIA) yielded comparable outcomes. A large reflected backward compression wave was seen proximal to the coarctation. Both techniques, WSA and WIA, gave the same results in terms of P(+) and P(-). A descending index (DI) was formulated as the difference between peak systolic pressure and valve closure pressure, divided by the pulse pressure. DI increased with stenosis severity for mild to moderate aortic coarctations that did not yet cause evident hypertension. This index may allow for early diagnosis by noninvasive estimation of coarctation severity.

Angular (Gothic) aortic arch leads to enhanced systolic wave reflection, central aortic stiffness, and increased left ventricular mass late after aortic coarctation repair: evaluation with magnetic resonance flow mapping

OBJECTIVE

We sought to investigate the mechanism whereby a particular deformity of the aortic arch, an angulated Gothic shape, might lead to hypertension late after anatomically successful repair of aortic coarctation.

METHODS

Fifty-five normotensive patients with anatomically successful repair of aortic coarctation and either a Gothic (angulated) or a Romanesque (smooth and rounded) arch were studied with magnetic resonance angiography and flow mapping in both the ascending and descending aortas. Systolic waveforms, central aortic stiffness, and pulse velocity were measured. We hypothesized that arch angulation would result in enhanced systolic wave reflection with loss of energy across the aortic arch, as well as increased central aortic stiffness.

RESULTS

Twenty patients were found to have a Gothic, and 35 a Romanesque, arch. Patients with a Gothic arch showed markedly augmented systolic wave reflection (12 +/- 6 vs 5 +/- 0.3 mL, P < .001) and greater loss of systolic wave height in the distal aorta (30% +/- 16% vs 22% +/- 12%, P < .01) compared with that of subjects with a Romanesque arch. Pulse wave velocity was also increased with a Gothic arch (5.6 +/- 1.1 vs 4.1 +/- 1 m/s, P < .0001), as well as left ventricular mass index (85 +/- 15 vs 77 +/- 20 g/m2). Patients with a Romanesque arch had increased aortic stiffness compared with that of control subjects (stiffness beta-index, 3.9 +/- 0.9 vs 2.9 +/- 1; P = .03).

CONCLUSIONS

Angulated Gothic aortic arch is associated with increased systolic wave reflection, as well as increased central aortic stiffness and left ventricular mass index. These findings explain (at least in part) the association between this pattern of arch geometry and late hypertension at rest and on exercise in subjects after coarctation repair.

Increased central aortic stiffness and left ventricular mass in normotensive young subjects after successful coarctation repair

BACKGROUND

Hypertension occurs in 20% to 40% of survivors of anatomically successful repair of aortic coarctation (CoA). The aim of the present study was to examine the role of central aortic function in this setting.

METHODS

Forty normotensive asymptomatic subjects with successful CoA repair (age 12 +/- 8 years) and 20 age- and sex-matched control subjects underwent detailed magnetic resonance imaging investigation of the thoracic aorta and left ventricle. Aortic distensibility, compliance, and stiffness beta index were calculated in the central (precoarctation) and descending (postcoarctation) aorta. Aortic pulse wave velocity was measured and left ventricular mass was calculated.

RESULTS

Compared to control subjects, CoA subjects had markedly decreased central aortic distensibility (2.8 +/- 0.7 vs 4.2 +/- 0.5 mm Hg(-1) x 10(-3), P < .001) and compliance (1.7 +/- 0.3 vs 2.5 +/- 0.6 mm2 mm Hg(-1), P < .001) and increased stiffness beta index (5.2 +/- 1 vs 2.5 +/- 0.6, P < .001). Pulse wave velocity was also significantly increased in the CoA subjects (4.7 +/- 1.3 vs 3.3 +/- 0.6 m/sec, P < .001). Left ventricular mass index was higher in the CoA subjects (84 +/-11 vs 73 +/-10 g/m2, P = .01) and correlated significantly with aortic stiffness beta index (r2 = 0.8, P < .0001). By contrast, descending aortic characteristics were similar in the CoA and control subjects.

CONCLUSION

Central aortic stiffness is markedly increased and associated with increased left ventricular mass in normotensive young subjects after successful early repair of CoA.

Coarctation Long-term Assessment (COALA): Significance of arterial hypertension in a cohort of 404 patients up to 27 years after surgical repair of isolated coarctation of the aorta, even in the absence of restenosis and prosthetic material

OBJECTIVE

Recent studies have demonstrated that there is a loss of aortic compliance in patients after coarctation repair. The clinical effect of this and other mechanisms apart from restenosis on the rate of arterial hypertension is unknown.

METHODS

From 1974 through 2000, 404 patients born before January 1, 1985, underwent surgical intervention for isolated aortic coarctation. From those 382 who are still alive, 273 patients aged 16 to 73 years (1-27 years after surgical intervention) underwent a structured clinical investigation according to a prospective protocol, including blood pressure measurement at all limbs, ambulatory blood pressure measurement, and symptom-limited exercise testing.

RESULTS

Sixty-seven (25%) patients were already taking antihypertensive drugs, and another 63 (23%) patients had an increased ambulatory blood pressure. Still another 26 (10%) patients had a blood pressure during exercise exceeding 2 standard deviations of reference values. Only 117 (43%) patients had a normal blood pressure reaction. From those 156 patients with hypertension, only 21 (13%) had a systolic brachial-ankle blood pressure difference of greater than 20 mm Hg, suggesting restenosis. In the patient group without restenosis (n = 245), independent risk factors for hypertension were repair with prosthetic material, male sex, a residual brachial-ankle blood pressure difference, and older age at follow-up.

CONCLUSIONS

The majority of patients were hypertensive at long-term follow-up after coarctation repair. This is caused by restenosis, defined by a gradient of greater than 20 mm Hg, in only a few patients. Even in those without prosthetic material or minimal-grade restenosis, there is a substantial incidence of arterial hypertension.

Impact of transverse aortic arch hypoplasia after surgical repair of aortic coarctation: An exercise echo and magnetic resonance imaging study

BACKGROUND

We sought to assess the impact of persistent hypoplasia of the transverse aortic arch (TAA) after repair of aortic coarctation (AoC), on blood pressure response to exercise, left ventricular (LV) hypertrophy and presence of collateral circulation.

METHODS

34 consecutive patients with end-to-end repair of AoC (age at repair 3.2+/-2.5 years) underwent exercise echocardiography and magnetic resonance imaging (MRI) at 24+/-7 years of age (range 11.3 to 44.6 years). Systolic Doppler pressure gradient (SPG) across the descending aorta and blood pressure at the right arm were measured at baseline and every minute throughout all exercise. Magnetic resonance imaging was used to measure LV mass index, presence and amount of collateral flow, and the diameters of the aortic isthmus and TAA indexed to the diameter of the diaphragmatic.

RESULTS

Aortic isthmus index was higher than that of the TAA (p=0.006). We observed LV hypertrophy in 15 patients (45%) and presence of collateral circulation in 14 (41%). Eighteen patients (53%) had an abnormal blood pressure response to exercise. Patients with abnormal pressure response to exercise had smaller TAA index (p=0.0005), but similar aortic isthmus index (p=0.09). They also had higher exercise SPG (p<0.0001), higher LV mass index (p<0.0001) and prevalence of LV hypertrophy (p=0.007), higher prevalence of collateral circulation (p<0.0001) and a higher amount of collateral flow (p<0.0001). TAA index, but not aortic isthmus index, correlated with exercise blood pressure (r=-0.59, p=0.003), exercise SPG (r=-0.70, p=0.0005), amount of collateral flow (r=-0.74, p=0.0002) and LV mass index (r=-0.68, p=0.0007).

CONCLUSIONS

After repair of AoC, hypoplasia of the TAA may be responsible for abnormal blood pressure response to exercise, persistence of collateral circulation and LV hypertrophy.

Long-term results (up to 18 years) of balloon angioplasty on systemic hypertension in adolescent and adult patients with coarctation of the aorta

BACKGROUND

Little is known regarding the long-term follow-up results of balloon angioplasty (BA) for patients with aortic coarctation (AC) on systemic hypertension.

HYPOTHESIS

To define the long-term effect of BA of AC on systemic hypertension in adolescent and adult patients.

METHODS

Follow-up data of 53 patients (36 male), mean age 24 +/- 9 years, undergoing BA for discrete AC at median interval of 11.8 years (range, 4-18 years), including cardiac catheterization, magnetic resonance imaging (MRI), and echocardiography. Patients were divided into two groups at 1 year after BA on the basis of absence (group A: 40 patients) or presence (group B: 11 patients) of persistent hypertension and need for medication.

RESULTS

Fifty-one patients had baseline hypertension, BA produced an immediate reduction in peak AC gradient from 66 +/- 23 mmHg to 10.8 +/- 7 mmHg (p < 0.0001). The immediate systolic blood pressure (SBP) decreased from 165 +/- 17 mmHg (95% CI: 159 to 171) to 125 +/- 10 mmHg (95% CI: 122 to 131) (p < 0.001) in 40 patients (group A) and from 184 +/- 19 mmHg (95% CI: 169 to 198) to 142 +/- 22 mmHg (95% CI: 124 to 156) (p<0.001) in 11 patients (group B). At 1-year follow-up, SBP decreased further to 115 +/- 10 in group A (95% CI 111-119) and 134 +/- 19 in group B (95% CI 122-142) (p<0.001). The blood pressure had normalized without medication in group A (165 +/- 17 to 115 +/- 10 mmHg).

CONCLUSION

Long-term results of BA for discrete AC are excellent and should be considered as the first option for treatment of this disease. No paradoxical hypertension occurred post angioplasty, and normalization of blood pressure without medication occurred in 78% of the patients after BA.

Vascular Remodeling After “Successful” Repair of Coarctation

OBJECTIVES

This study was designed to investigate the influence of aortic arch geometry on vascular remodeling after anatomically successful repair of coarctation of the aorta (CoA).

BACKGROUND

Abnormalities of the precoarctation vasculature are known to occur after CoA repair and appear related to adverse outcomes. The influence of aortic arch geometry on such abnormalities is unknown.

METHODS

Sixty-three postcoarctectomy subjects (age 15.9 +/- 6.3 years) were compared with 63 control volunteers. Aortic arch shape was characterized on magnetic resonance imaging using both qualitative classification, identifying 3 subtypes of arch geometry (Gothic, Crenel, Romanesque), and a quantitative index, height/width ratio (H/W) of the aorta. Using ultrasound, we measured carotid artery intima-media thickness (IMT) and stiffness index and distensibility, as well as right brachial artery flow-mediated dilation (FMD) and glyceryl trinitate (GTN)-induced dilatation, to assess the precoarctation vasculature of these subjects.

RESULTS

Gothic arch type was associated with higher carotid IMT and stiffness index, lower carotid distensibility (p < 0.001 for all), and lower brachial reactivity (FMD, p < 0.01; GTN response, p < 0.001) compared with Crenel and Romanesque geometries and with control subjects. The height/width ratio was also significantly related to these vascular abnormalities. Even in CoA subjects with Romanesque arch geometry, arterial function and stiffness parameters were significantly impaired compared with control subjects.

CONCLUSIONS

In young adult survivors of anatomically successful CoA repair, a gothic-type aortic arch with high H/W is associated with abnormal IMT, higher aortic stiffness index, and impaired arterial reactivity in the pre-CoA vasculature.

Elastic properties of the reconstructed aorta in hypoplastic left heart syndrome

BACKGROUND

Patients with repaired coarctation of the aorta retain abnormal elastic properties of the aorta. It is not known whether patients with hypoplastic left heart syndrome also manifest abnormal elastic properties after palliative surgery. The presence of such abnormalities may have important clinical implications as reduced aortic compliance might adversely impact single right ventricular function.

METHODS

We prospectively evaluated the elastic properties of the aorta in a cohort of patients with hypoplastic left heart syndrome who had undergone the Norwood procedure with aortic arch reconstruction and subsequent bidirectional Glenn or Fontan procedure. The hypoplastic left heart syndrome patients (n = 20) were compared with single-ventricle patients (n = 18) without history of arch reconstruction and patients with double-ventricular lesions (n = 22). Aortic elastic function was quantified by distensibility index and stiffness index. M-mode measurements of the transverse aortic arch were obtained with transesophageal echocardiography under general anesthesia. Patients were evaluated at a median age of 22.2 months with no age difference between patient subgroups.

RESULTS

Distensibility index was significantly less (p = 0.007) and stiffness index greater (p = 0.005) in the reconstructed arch of hypoplastic left heart syndrome patients compared with single-ventricle and double-ventricle patients.

CONCLUSIONS

Patients with hypoplastic left heart syndrome after Norwood palliation have increased aortic stiffness and decreased distensibility in the reconstructed transverse arch. As previous studies in adults have shown that decreased aortic compliance increases the energy cost of cardiac ejection, examination of modifications to the surgical technique that might improve elastic properties is warranted.

Evidence for Cardiovascular Autonomic Dysfunction in Neonates With Coarctation of the Aorta

Background— Coarctation of the aorta (CoA) is associated with hypertension and abnormalities of blood pressure control, which persist after late repair. Assumptions that neonatal repair would prevent development of blood pressure abnormalities have not been supported by recent data. We hypothesized that early pathological adjustment of autonomic cardiovascular function may already be established in the neonate with coarctation.

Methods and Results— We studied 8 otherwise well neonates with simple CoA and compared measures of spontaneous baroreflex sensitivity, heart rate variability, and blood pressure variability with 13 healthy newborn babies. Spontaneous baroreflex sensitivity was calculated with sequence methodology from an ECG, and noninvasive blood pressure was recorded with a Portapres. Heart rate variability was determined with time- and frequency-domain measures. Blood pressure variability was measured in the frequency domain. In comparison with normal controls, neonates with CoA had raised blood pressure (78.9±3.8 versus 67.1±2.1 mm Hg), depressed baroreflex sensitivity (8.7±1.5 versus 13.8±1.1 ms/mm Hg), reduced heart rate variability (total power 16.5±3.1 versus 31.5±2.2 ms 2 ), and an increase in the high-frequency component of blood pressure variability (3.1±0.3 versus 2.2±0. 2 mm Hg 2 ). This is not the pattern expected if neonates with CoA simply had subclinical cardiac failure.

Conclusions— These data suggest that infants with CoA already show signs of pathological adjustment of autonomic cardiovascular homeostasis. Further longitudinal studies are required to determine whether these alterations play a role in the increased risk of late hypertension in these patients.