The importance of the early diagnosis of aorta coarctation

SUMMARY INTRODUCTION: Coarctation of the aorta is a congenital heart disease characterized by a narrowing that occurs in the aortic artery. This constriction can occur anywhere along its entire length; however, it is more common between the origin of the left subclavian artery and the ductus arteriosus. Its incidence corresponds to 3 cases per 10,000 births. Thus, it is a common cardiopathy, but with high mortality and morbidity rates, which are related to a failure in the early diagnosis. METHOD: In the research, articles of the national and international literature in Pubmed, Scielo and Lilacs databases were selected using the following descriptors: coarctation, aorta, diagnosis, heart diseases, congenital abnormalities. RESULTS: The pathophysiology of CoA and its systemic implications in the life of newborn and adults are well elucidated. However, due to the lack of habit to palpate pulses and to check the blood pressure in both upper and lower limbs during the physical examination, it is still a pathology little diagnosed in childhood. There are several techniques used in the repair of coarctation, each with their specifics, although, when not treated, aneurysms, heart failure, coronary diseases, and stroke are the main complications arising from the evolution of this pathology, which explains the low survival rate of these patients. CONCLUSION: Coarctation of the aorta is, therefore, a cardiac malformation of significant importance due to its incidence and its significant mortality risk. In this sense, the early diagnosis stands out as an essential piece for better prognosis of the patient.

RESUMO INTRODUÇÃO: A coarctação da aorta é uma cardiopatia congênita caracterizada por um estreitamento que ocorre na artéria aorta. Essa constrição pode ocorrer em qualquer local ao longo de toda a sua extensão, entretanto, é mais comum entre a origem da artéria subclávia esquerda e o ducto arterioso. Sua incidência corresponde a três casos a cada 10.000 nascimentos, sendo, desse modo, uma cardiopatia comum, porém com elevada taxa de mortalidade e morbidade, as quais estão relacionadas à falha no diagnóstico precoce. MÉTODOS: Este artigo trata-se de uma revisão bibliográfica narrativa da literatura. Na pesquisa foram selecionados artigos na literatura nacional e internacional nas bases de dados PubMed, SciELO e Lilacs, utilizando-se os seguintes descritores: coarctação, aorta, diagnóstico, cardiopatias, anormalidades congênitas. RESULTADOS: A fisiopatologia da coarctação da aorta e as implicações sistêmicas dessa cardiopatia na vida do recém-nascido e do adulto estão bem elucidadas. Entretanto, devido à falta de costume em palpar pulsos e aferir a pressão arterial nos membros superiores e inferiores durante o exame físico, ainda é uma patologia pouco diagnosticada na infância. Existem diversas técnicas utilizadas no reparo da coarctação, cada uma com suas especificidades, porém, quando não tratada, aneurismas, insuficiência cardíaca, coronariopatias e acidentes vasculares encefálicos são as principais complicações provenientes da evolução dessa patologia, o que explica uma baixa sobrevida desses pacientes. CONCLUSÃO: A coarctação da aorta é, portanto, uma malformação cardíaca de importância relevante devido a sua incidência e ao seu potencial risco de mortalidade. Nesse sentido, o diagnóstico precoce destaca-se como peça fundamental para um melhor prognóstico do paciente.

En el modelo preclínico de insuficiencia cardíaca por disfunción sistólica en ratón (coartación de aorta torácica) la velocidad de flujo carotídeo determinada precozmente se asocia a función ventricular izquierda tardía / Carotid flow velocity is associated to late ventricular function in mice with preclinic systolic dysfunction induced by thoracic aortic coarctation

Resumen: Los modelos experimentales de falla cardíaca con fracción de eyección disminuida en murinos son pocos. Uno de estos modelos es el de coartación de la aorta torácica en el arco aórtico (COA) en ratones. Un aspecto importante en su desarrollo es la evaluación precoz del procedimiento y su relación con la función sistólica posterior. En este sentido, las velocidades de flujo carotídeo y la relación entre ambos flujos (derecho, pre-coartación; izquierdo post coartación) pueden permitir evaluar tempranamente la precisión del procedimiento y relacionarse más tardíamente con la función sistólica VI. Nuestro objetivo fue comparar precozmente (semana 2 post operatoria) las velocidades de flujo en ambas carótidas (Doppler continuo) y tardíamente (semana 5 postoperatoria) la función sistólica VI (Ecocardiograma de superficie) en ratones seudocoartados o sham (n= 6) vs ratones COA (n = 12). Se confirmó una diferencia estadísticamente significativa en la relación de velocidades de flujo entre ambas carótidas medida precozmente entre los ratones sham y COA (1,1 ± 0,1 vs 2,5 ± 0,5, p< 0,001), lo que se correlacionó con un deterioro significativo de la función sistólica del ventrículo izquierdo evaluada a las 5 semanas en los ratones COA. Conclusión: En este modelo preclínico de falla cardíaca por sobrecarga de presión con fracción de eyección VI disminuida en ratón, el aumento precoz de la velocidad de flujo en la arteria carótida derecha (pre-coartación en el modelo COA) y sobre todo de la relación entre las velocidades de flujo carotídeo entre ambas carótidas se asocia a deterioro importante de la función sistólica VI cinco semanas después de efectuada la COA, lo que permite predecir la efectividad del procedimiento en este modelo experimental.

Abstract: There are few experimental models of heart failure with reduced ejection fraction in murines. One of these models is transverse aortic coarctation (TAC) in mice. However, an important challenge in its development is the early evaluation of the procedure and its relationship with late systolic LV function. In this sense, carotid flow velocities and the relationship between both (right, precoarctation, left post-coarctation) may allow early evaluation of the accuracy of the procedure and be related to late LV systolic function. The aim was to compare early (week 2 post-operative) flow velocities determined in both carotid arteries (by continuous Doppler) with late (week 5 postoperative) LV systolic function (by echocardiogram) in sham (n= 6) vs. TAC (n: 12) mice. We confirmed a statistically significant difference in the early ratio of carotid flow velocities (left/right common carotid velocity ratio) between sham and TAC mice (1.1 ± 0.1 vs 2.5 ± 0.5, p< 0.001) and this correlated well with a deteriorated left ventricular function in the TAC mice after 5 weeks. In this preclinical model of cardiac failure due to pressure overload with reduced LV ejection fraction in the mouse, the early increase in right carotid flow velocity (precoarctation) and especially the relationship between precoarctation/postcoarctation carotid flow velocities is associated with significant impairment of LV systolic function five weeks after the TAC, which allows to predict the effectiveness of the procedure in this experimental model.

Inhibition of PKC-dependent extracellular Ca2+ entry contributes to the depression of contractile activity in long-term pressure-overloaded endothelium-denuded rat aortas

We examined the contractile responsiveness of rat thoracic aortas under pressure overload after long-term suprarenal abdominal aortic coarctation (lt-Srac). Endothelium-dependent angiotensin II (ANG II) type 2 receptor (AT2R)-mediated depression of contractions to ANG II has been reported in short-term (1 week) pressure-overloaded rat aortas. Contractility was evaluated in the aortic rings of rats subjected to lt-Srac or sham surgery (Sham) for 8 weeks. ANG I and II levels and AT2R protein expression in the aortas of lt-Srac and Sham rats were also evaluated. lt-Srac attenuated the contractions of ANG II and phenylephrine in the aortas in an endothelium-independent manner. However, lt-Srac did not influence the transient contractions induced in endothelium-denuded aortic rings by ANG II, phenylephrine, or caffeine in Ca2+-free medium or the subsequent tonic constrictions induced by the addition of Ca2+ in the absence of agonists. Thus, the contractions induced by Ca2+ release from intracellular stores and Ca2+ influx through stored-operated channels were not inhibited in the aortas of lt-Srac rats. Potassium-elicited contractions in endothelium-denuded aortic rings of lt-Srac rats remained unaltered compared with control tissues. Consequently, the contractile depression observed in aortic tissues of lt-Srac rats cannot be explained by direct inhibition of voltage-operated Ca2+ channels. Interestingly, 12-O-tetradecanoylphorbol-13-acetate-induced contractions in endothelium-denuded aortic rings of lt-Srac rats were depressed in the presence but not in the absence of extracellular Ca2+. Neither levels of angiotensins nor of AT2R were modified in the aortas after lt-Srac. The results suggest that, in rat thoracic aortas, lt-Srac selectively inhibited protein kinase C-mediated activation of contraction that is dependent on extracellular Ca2+ entry.

4D FLOW: una nueva herramienta de diagnóstico para cardiopatías congénitas / 4D Flow MRI: a new diagnostic tool for congenital heart diseases

Purpose. To demonstrate the utility of 4D flow MR imaging for analyzing blood flow patterns and flow distribution in patients with congenital heart diseases. Methods: Six patients with congenital heart diseases were scanned using a standard cardiac MRI protocol, according to their condition. Additionally, 2D flow sequences of the great vessels, and a 4D flow sequence covering the entire heart were acquired. Flow patterns were visualized by using vector fields, streamlines and particle traces. Results: 4D flow technique depicted vortices and helical flow in the pulmonary artery of most patients, as well as in the aorta and superior vena cava of one patient with corrected aortic coarctation and a levoatrial cardinal vein. Conclusion: 4D flow MR imaging enables the identification of flow patterns difficult to detect with other diagnostic modalities. Comprehensive evaluation of flow patterns might help to understand the hemodynamic consequences of congenital heart diseases and their surgical procedures.

Objetivo. Demostrar la utilidad de 4D flow para el análisis de patrones y distribución de flujos en pacientes con cardiopatías congénitas. Métodos: Seis pacientes con cardiopatías congénitas fueron escaneados con un protocolo de resonancia magnética cardíaca estándar. Además se incluyeron secuencias de flujo 2D en los principales vasos del tórax y una secuencia 4D flow que cubría todo el corazón. Para la visualización de los patrones de flujo se emplearon vectores de velocidad, líneas de flujo y trazadores de partículas. Resultados: 4D flow reveló vórtices y hélices en la arteria pulmonar de la mayoría de los pacientes, y en la aorta y vena cava superior de un paciente con coartación aórtica reparada y vena cardinal levoatrial. Conclusiones: 4D flow permite identificar patrones de flujo en pacientes con cardiopatías congénitas, difíciles de observar con otros métodos diagnósticos. La evaluación de patrones de flujo podría contribuir a comprender las consecuencias hemodinámicas de diferentes cardiopatías congénitas.

Efecto de la coartación aórtica en la producción de óxido nítrico por el endotelio vascular / Effect of aortic coarctation on nitric oxide production by vascular endothelium

El óxido nítrico es un potente vasodilatador liberado de endotelio, que se asocia a un efecto regulador del tono vascular y de la presión arterial. En este estudio se evaluó la reactividad vascular a fenilefrina y acetilcolina de anillos de aorta de ratas control e hipertensas por coartación de la aorta, y la liberación de óxido nítrico de los anillos arteriales, en condiciones basales y después de incubarlos con acetilcolina. La reactividad vascular se evalúo en los segmentos superior e inferior a la coartación de la aorta. La vasoconstricción producida por fenilefrina fue mayor en los anillos del segemento superior de las ratas hipertensas en comparación a las ratas control; los anillos de los segmentos inferiores de ambos grupos, no mostraron diferencias significativas. La relajación por acetilcolina mostró una CE50 mayor en los segmentos superiores de las ratas hipertensas; los segmentos inferiores de ambos grupos no mostraron diferencias significativas. Los anillos de aorta de ratas hipertensas tuvieron mayor producción de óxido nítrico en comparación al grupo control, siendo significativamente mayor la producción de los segmentos inferiores, lo cual sugiere que el "shear stress" de estos segmentos estimuló la producción de óxido nítrico

Balloon dilatation of simple aortic coarctation in neonates and infants.

Twenty-one infants with isolated native coarctation of aorta (mean age 4.73 +/- 2.85 months, range 15 days-12 months) underwent balloon dilatation in the last seven years at our institute. Seven of them were less than three months and 14 were older than three months. The procedure was successful in relieving the coarctation (gradient < 20 mm Hg) in five of seven (71%) infants up to three months and 12 of 14 (86%) above three months. Peak systolic gradients decreased from 70.8 +/- 20.1 to 14.5 +/- 11 mm Hg in the younger infants and from 47.7 +/- 11.7 to 11.4 +/- 9.9 mm Hg in infants above three months. Post-dilatation angiogram showed the coarctation segment to be equal to the isthmus in both the groups, 0.96 +/- 0.14 and 0.96 +/- 0.12 respectively. One three months old infant died immediately after a successful dilatation possibly due to coronary embolism, and another neonate died a few days later of unrelated pre-existing septicemia. Left ventricular function improved in all the infants with depressed preprocedure ejection fraction. Restenosis defined as peak instantaneous echo-Doppler gradient above 20 mm Hg with a significant narrowing on two-dimensional echocardiography occurred in all the five infants up to three months over a period of 1 to 12 months. Follow-up information over a period of 4 to 24 months was available in 11 of 14 older infants of which three had restenosis. Gradients progressively increased in all the four infants (2 of either group) with an initial partially successful result. A small isthmus relative to the descending thoracic aorta at diaphragm is an important predictor of restenosis/inadequate result. This discrepancy was seen much more in smaller infants, post-dilatation coarctation index being 0.68 +/- 0.11 vs 0.81 +/- 0.16 (p = 0.07). Four of the infants underwent a repeat successful dilatation. Balloon dilatation is safe and effective in infants above three months of age. In infants up to three months the procedure is feasible and leads to improvement in left ventricular function, but restenosis occurs rapidly in all of them.

Vasopressor mechanisms in acute aortic coarctation hypertension

Angiotensin II (ANGII) and vasopressin (AVP) act together with the mechanical effect of aortic constriction in the onset of acute aortic coarctation hypertension. Blockade of ANG II and AVP V(1) receptors demonstrated that ANG II acts on the prompt (5 min) rise in pressure whereas AVP is responsible for the maintenance (30-45 min) of the arterial pressure elevation during aortic coarctation. Hormone assays carried out on blood collected from conscious rats submitted to aortic constriction supported a role for ANG II in the early stage and a combined role for both ANG II and AVP in the maintenance of proximal hypertension. As expected, a role for catecholamines was ruled out in this model of hypertension, presumably due to the inhibitory effect of the sinoaortic baroreceptors. The lack of afferent feedback from the kidneys for AVP release from the central nervous system in rats with previous renal denervation allowed ANG II to play the major role in the onset of the hypertensive response. Median eminence-lesioned rats exhibited a prompt increase in proximal pressure followed by a progressive decline to lower hypertensive levels, revealing a significant role for the integrity of the neuroaxis in the maintenance of the aortic coarctation hypertension through the release of AVP. In conclusion, the important issue raised by this model of hypertension is the likelihood of a link between some vascular territory-probably renal - below the coarctation triggering the release of AVP, with this vasoconstrictor hormone participating with Ang II and the mechanical effect of aortic constriction in the acute aortic coarctation hypertension.

Coarctação da Aorta e Síndrome de Turner / Coarctation of the Aorta and Turner's Syndrome

coarctação da aorta faz parte das cardiopatias congênitas acianóticas,responsável por cerca de cinco, oito por cento das cardiopatias congênitas, sendo uma causa corrigível de hipertensão arterial sistêmica secundária. FreqÜentemente associa-se a outras anomalias cardíacas, sendo as valva aórtica bicúspide a mais prevalente, e extra-cardíacas como os aneurismas do polígono de Willis. A síndrome de Turner representa uma digenesia gonadal, com achados fenotípicos característico e geralmente associa-se a cardiopatias congênitas vinte, cinquenta por cento, sendo que a coarctação da aorta representa quarenta e cinco por cento destas...

Effect of chronic estradiol administration on the acute pressor response to aortic coarctation in conscious rats

We investigated the effect of chronic estradiol administration on the pressor response elicited by acute (45 min) partial aortic constriction in conscious Wistar rats and on vascular reactivity to angiotensin II and vasopressin in vitro. Estradiol or vehicle was administered for 7 days to young castrated male and female rats and to female rats that had stopped cycling. In the acute experiment of aortic coarctation in concious rats, carotid pressure was monitored continuously before and for 45 min after partial abdominal aortic coarctation. In ovariectomized females the mean carotid pressure and heart rate before aortic coarctation were significantly lower in estradiol treated animals. Estradiol did not affect the pressor response to aortic coarctation of castrated male rats or ovariectomized female rats but blunted the reflex bradycardia of ovariectomized rats. The onset of the pressor response to aortic coarctation was delayed in aged female rats as compared to the other groups. While estradiol treatment significantly accelerated the onset of hypertension in aged rats, it did not affect the pressor response of castrated animals. Full dose-response curves to angiotensin II and vasopressin were constructed in vitro in the isolated mesenteric arterial bed obtained from similary treated groups. Estradiol did not affectthe vasopressin sensitivity or responsiveness of any group, but caused a significant increase in angiotensin II sensitivity in ovariectomized rats only. In conclusion, these data slow that chronic estradiol administration ot aged female rats accelerate the installation of the pressor response to acute aortic coarctation. In addition, estradiol administration to ovariectomized rats is associated with lower blood pressure and heart rate.

Effect of bilateral nephrectomy on hypertension produced by acute aortic coarctation

1. The hemodynamic responses to acute (45 min) aortic coarctation were studied in conscious intact (N = 7) or bilaterally nephrectomized (N = 7) Wistar rats (250-320 g). The degree of constriction of the aorta was monitored by reducing aortic flow (measured with a pulsed Doppler flowmeter) to 40 per cent of the basal level. 2. The nephrectomized rats presented a smaller (P < 0.05) increase in carotid pressure (14-17 per cent ) than the intact rats (25-36 per cent ). Although the aortic constriction reduced significantly the aortic flow to 40 per cent of the basal level in both groups of rats, the calculated change in aortic resistance imposed by coarctation in the intact group was significantly (P < 0.05) higher (167-292 per cent ) than that observed (173-183 per cent ) in the nephrectomized group, except 5 min after coarctation. 3. The hemodynamic data obtained in the present study confirm our findings that nephrectomized rats display a blunted hypertensive response to acute aortic coarctation which is attributed mainly to the mechanical effect of constriction. In addition, the present data indicate that the release of vasopressor substances triggered by the kidneys in intact subjects are responsible for the gradual increase in aortic resistance during coarctation

Balloon angioplasty for native aortic coarctation.

From May 1987 to August 1990, eighteen patients underwent balloon angioplasty for native aortic coarctation. The age of the patients ranged from four to fifty six years (mean age 17.5 years). The procedure was successful in all cases with a reduction in the peak gradient across the coarctation from 61 +/- 19 mm Hg to 11.7 +/- 8.1 mmHg (p < 0.05). The coarcted segment increased from 4.5 +/- 1.9 mm to 10.7 +/- 3.9 mm (p < 0.05). Peak gradient at six to twelve months follow up, obtained in ten patients, was 19.8 +/- 10.1 mmHg (p = NS). There were no life threatening complications, although seven patients had local vascular problems after the procedure. In two patients, there was persistence of hypertension necessitating drug therapy. On haemodynamic and angiographic restudy in 10 patients, one patient had restenosis and none had aneurysm formation. We conclude that balloon angioplasty is a safe, and less invasive alternative to surgery for native aortic coarctation with gratifying immediate and short term results.

Percutaneous balloon angioplasty for native coarctation of the aorta. Early and intermediate term results.

We performed balloon angioplasty (BA) in 12 patients with native coarctation of the aorta (COA), aged 2-32 years (average 20.7). The peak systolic gradient across the COA segment decreased from 60.75 +/- 21.85 to 15.66 +/- 9.44 mmHg (p less than 0.001) after the procedure. Angiographically all had more than 50% increase in the diameter of the narrowed segment. During clinical follow up (2.42 months post procedure), all had marked symptomatic benefit. Follow up by haemodynamics and angiography in 4 cases (average 7.7 months post BA) and by echo-doppler in 2 cases (3.6 months post BA) revealed no evidence of aneurysm or restenosis. Our results indicate that BA is a simple, safe, nonoperative alternative to surgery in COA. The immediate and intermediate follow up results are encouraging; however, long term studies are needed to define the true incidence of restenosis and aneurysm.

Participación de factores mecánicos y renohumorales en la elevación de la tensión arterial en pacientes con coartación de la aorta / Mechanical and renohumoral factors participating in arterial pressure rising in patients with aortic coarctation

Se estudian siete pacientes con coartación aórta bajo cuatro situaciones diferentes para valorar la participación de los factores mecánico y renohumoral en la hipertensión de la coartación: 1) control, 2) tratamiento con propranolol, 3) tratamiento con captopril y 4) periodo postoperatorio. La tensión arterial humoral media disminuyó de 108 + 11 mmHg en el período de control a 95 ñ 13 mmHg con propranolol, 91 ñ 11 mmHg con captopril y 85 ñ 10 en periodo postoperatorio. La disminución fue significativamente mayor con captopril que con propranolol (p < 0.01), y también con la correción quirúrgica de la coartación que con cualesquiera de los dos fármacos (p < 0.01). La actividad de renina plasmática y la frecuencia cardiaca aumentaron en el periodo postoperatorio con respecto al período de control de 5.23 ñ 3.5 a 12.000 ñ 3.24 ng/ml/h (p < 0.05) y, 84 ñ 9 a 93 ñ 10 lpm (p < 0.001), respectivamente. Estos datos pueden explicarse por resituación de los barorreceptores. El sistema de renina y angiotensina participa en la patogénesis de la hipertensión de la coartación aórtica, aunque no es el único factor