Hybrid repair of a very late, post-aortic coarctation surgery thoracic aneurysm: a case report

ABSTRACT: INTRODUCTION: Local aneurysms after surgical repair of coarctation of the aorta occur mainly in patients surgically treated by Dacron patch plasty during adulthood. The management of these patients is always problematic, with frequent complications and increased mortality rates. Percutaneous stent-graft implantation avoids the need for surgical reintervention. CASE PRESENTATION: We report a case involving the hybrid treatment by stent-graft implantation and transposition of the left subclavian artery to the left common carotid artery of an aneurysmal dilatation of the thoracic aorta that occurred in a 64-year-old Caucasian man, operated on almost 40 years earlier with a Dacron patch plasty for aortic coarctation. Our patient presented to our facility for evaluation with back pain and shortness of breath after minimal physical effort. A physical examination revealed stony dullness to percussion of the left posterior thorax, with no other abnormalities. The results of chest radiography, followed by contrast-enhanced computed tomography and aortography, led to a diagnosis of giant aortic thoracic aneurysm. Successful treatment of the aneurysm was achieved by percutaneous stent-graft implantation combined with transposition of the left subclavian artery to the left common carotid artery. His post-procedural recovery was uneventful. Three months after the procedure, computed tomography showed complete thrombosis of the excluded aneurysm, without any clinical signs of left lower limb ischemia or new onset neurological abnormalities. CONCLUSIONS: Our patient's case illustrates the clinical outcomes of surgical interventions for aortic coarctation. However, the very late appearance of a local aneurysm is rather unusual. Management of such cases is always difficult. The decision-making should be multidisciplinary. A hybrid approach was considered the best solution for our patient.     

Aortic coarctation: the need for lifelong surveillance

Survival of patients with aortic coarctation improved dramatically after surgical repair became available and the number of patients who undergo surgery and reach adulthood is steadily increasing. However, life expectancy is still not as normal as in unaffected peers. Cardiovascular complications are frequent and require indefinite follow-up. Concern falls chiefly into five categories: recoarctation, endocarditis, stenotic and/or incompetent coexisting bicuspid aortic valve, aortic aneurysm formation and systemic hypertension. In this review, these complications, with particular reference to late hypertension, are discussed and strategies for the clinical management of postcoarctectomy patients are described.     

Mouse gridlock: no aortic coarctation or deficiency,but fatal cardiac defects in Hey2 -/- mice

Gridlock (grl) is one of the first mutations characterized from the large zebrafish mutagenesis screens, and it results in an arterial (aortic) maturation defect, which was proposed to resemble aortic coarctation, a clinically important human malformation. While the grl mutation appears to be a hypomorph, grl knockdown experiments have shown even stronger effects on arterial development. We have generated a knockout of the murine Hey2 (gridlock) gene to analyze the mammalian phenotype. Surprisingly, Hey2 loss does not affect aortic development, but it instead leads to a massive postnatal cardiac hypertrophy with high lethality during the first 10 days of life. This cardiomyopathy is ameliorated with time in surviving animals that do not appear to be manifestly impaired during adult life. These differences in phenotypes suggest that changes in expression or function of genes during evolution may lead to quite different pathological phenotypes, if impaired.     

Percutaneous treatment of native aortic coarctation in adults

Aortic coarctation is a common congenital cardiac defect, which can be diagnosed over a wide range of ages and with varying degrees of severity. We present two cases of patients diagnosed with aortic coarctation in adulthood. Both patients were treated by an endovascular approach. These cases demonstrate the variety of indications in which percutaneous treatment is an excellent alternative for surgical treatment in adult native coarctation patients.     

Coarctation of the aorta in adults.

Thirty-six patients, 19 men and 17 women, presented at age 18 or older between 1952 and 1974 with coarctation of the aorta. Of the 14 (39%) who had associated cardiovascular disease, 12 had aortic stenosis or insufficiency or both. Three patients had infections-two, endocarditis (aortic valve) and one, endarteritis. Three of the seven patients who did not undergo an operation are alive, two at more than 50 years of age. Five patients had myocardial infarctions, two at 35 years of age. Twenty-nine (80%) had operations; in eight instances the patient was over age 40. All 18 patients undergoing repair of isolated coarctation survived, while only 7 of the 11 patients with associated cardiovascular lesions who underwent repair recovered. Aortic valvular disease and myocardial infarction are serious complicating factors in coarctation of the aorta.     

Hypertrophy of the heart; electrocardiographic distinction between physiologic and pathologic enlargement

Electrocardiograms of marathon runners were examined to study hypertrophy of the heart due to prolonged physical exertion and to differentiate this from hypertrophy due to various disease states, especially essential hypertension, aortic valvular disease and coarctation of the aorta. The electrocardiogram of the marathon runners was characterized by a slow cardiac rate, high voltage of the QRS complexes and T waves in the standard and/or precordial leads with normal R/T ratios. There was moderate enlargement of the heart as observed on teleoroentgenogram. These findings are characteristic of physiologic hypertrophy of the heart and should be suspected among patients having a history of athletics calling for endurance. Immediately after running, all waves showed an increased voltage and the heart size decreased. The concept of the secondary T wave in hypertension as a part of the left ventricular strain pattern was challenged by the observation that the increased voltage of the R waves in lead V5 and other leads seen in marathon runners and in certain patients with hypertension, aortic stenosis, aortic insufficiency and coarctation of the aorta were not necessarily associated with typical discordant S-T segments and T waves. There was a higher incidence of dyspnea, angina pectoris and cardiac enlargement among hypertensive patients with discordant T waves than among hypertensive patients without these changes. Thus it is felt that the discordant waves are primary and are not merely secondary to the increased area of the R waves. Primary T waves suggest myocardial disease, possibly anoxia of the subendocardium.     

The influence of aortic dimensions on calculated wall shear stress in the mouse aortic arch

In this paper, the influence of the aortic dimensions of an investigated mouse on its resulting wall shear stress (WSS) was studied. A numerical model of a mouse aortic arch was created based on a micro-CT scan of a vascular corrosion cast of an 8-week-old wild type mouse. This model was then rescaled to obtain five models with aortic root diameters corresponding to five different stages in the mouse life cycle varying from late fetal (0.7 mm) to old adult (1.5 mm). Consistent with literature, WSS values much higher than those normally encountered in humans were found. WSS was found to decrease rapidly in early life stages and to reach a plateau in adulthood, thus supporting a mediating role for WSS in arterial growth. Our results show that WSS values for mice should be interpreted very cautiously, and if possible an animal-specific geometry with animal-specific boundary conditions should be used.     

HYPERTROPHY OF THE HEART—Electrocardiographic Distinction Between Physiologic and Pathologic Enlargement

Electrocardiograms of marathon runners were examined to study hypertrophy of the heart due to prolonged physical exertion and to differentiate this from hypertrophy due to various disease states, especially essential hypertension, aortic valvular disease and coarctation of the aorta. The electrocardiogram of the marathon runners was characterized by a slow cardiac rate, high voltage of the QRS complexes and T waves in the standard and/or precordial leads with normal R/T ratios. There was moderate enlargement of the heart as observed on teleoroentgenogram. These findings are characteristic of physiologic hypertrophy of the heart and should be suspected among patients having a history of athletics calling for endurance. Immediately after running, all waves showed an increased voltage and the heart size decreased. The concept of the secondary T wave in hypertension as a part of the left ventricular strain pattern was challenged by the observation that the increased voltage of the R waves in lead V5 and other leads seen in marathon runners and in certain patients with hypertension, aortic stenosis, aortic insufficiency and coarctation of the aorta were not necessarily associated with typical discordant S-T segments and T waves. There was a higher incidence of dyspnea, angina pectoris and cardiac enlargement among hypertensive patients with discordant T waves than among hypertensive patients without these changes. Thus it is felt that the discordant waves are primary and are not merely secondary to the increased area of the R waves. Primary T waves suggest myocardial disease, possibly anoxia of the subendocardium.     

Endovascular Treatment of Late Thoracic Aortic Aneurysms after Surgical Repair of Congenital Aortic Coarctation in Childhood

Background

In some patients, local surgery-related complications are diagnosed many years after surgery for aortic coarctation. The purposes of this study were: (1) to systematically evaluate asymptomatic adults after Dacron patch repair in childhood, (2) to estimate the formation rate of secondary thoracic aortic aneurysms (TAAs) and (3) to assess outcomes after intravascular treatment for TAAs.

Methods

This study involved 37 asymptomatic patients (26 female and 11 male) who underwent surgical repair of aortic coarctation in the childhood. After they had reached adolescence, patients with secondary TAAs were referred to endovascular repair.

Results

Follow-up studies revealed TAA in seven cases (19%) (including six with the gothic type of the aortic arch) and mild recoarctation in other six (16%). Six of the TAA patients were treated with stentgrafts, but one refused to undergo an endovascular procedure. In three cases, stengrafts covered the left subclavian artery (LSA), in another the graft was implanted distally to the LSA. In two individuals, elective hybrid procedures were performed with surgical bypass to the supraaortic arteries followed by stengraft implantation. All subjects survived the secondary procedures. One patient developed type Ia endoleak after stentgraft implantation that was eventually treated with a debranching procedure.

Conclusions

The long-term course of clinically asymptomatic patients after coarctation patch repair is not uncommonly complicated by formation of TAAs (particularly in individuals with the gothic pattern of the aortic arch) that can be treated effectively with stentgrafts. However, in some patients hybrid procedures may be necessary.     

An unexpected finding late after repair of coarctation of the aorta

We describe a late complication in a 75-year-old man 50 years after repair of a coarctation of the aorta (CoA). Two years after an aortic valve replacement, mitral valve repair and radiofrequency MAZE the patient presented with dyspnoea and right-sided heart failure, based on a large pseudoaneurysm of the descending aorta, compressing the main bronchus and possibly temporarily the pulmonary arterial system. After sealing the aneurysm with an endovascular stent the patient recovered uneventfully. Recommendations are made for follow-up in patients after repair of CoA. (Neth Heart J 2008;16:260-3.)     

Morphology of aortic arch obstruction with patent ductus arteriosus

Thirty-one hearts with aortic arch obstruction and patent ductus arteriosus were examined with special reference to associated cardiac anomalies. Six presented with complete interruption of the aortic arch, four with atretic isthmus, twelve with coarctation, and three with tubular hypoplasia. Associated cardiac anomalies were divided into two main groups: (1) septal defect with left-to-right shunt, and (2) left ventricular inflow and/or outflow obstruction. A high incidence (9/19=47.4%) of ventriculo-infundibular malalignment type of ventricular septal defect with subaortic stenosis was observed. Associated cardiac lesions that reduce blood flow in the aortic arch during fetal life may be responsible for poor development of this structure.     

Alteration of p66shc is associated with endothelial dysfunction in the abdominal aortic coarctation of rats

To examine the role of p66shc in endothelial dysfunction, we investigated the endothelium-dependent relaxation, protein expression and superoxide production in abdominal aortic coarctation rats. Endothelium-dependent relaxation to acetylcholine was impaired only in the aortic segments above the aortic coarctation (35.0+/-7.1% vs. 86.6+/-6.0% for sham control at 1 microM Ach). The aortic segments exposed to increased blood pressure showed a decreased phosphorylation of endothelial nitric oxide synthase, an increased phosphorylation of p66shc, and an increased superoxide production. Angiotensin II elicited a significantly increased phosphorylation of p66shc in the endothelial cells. Taken together, these findings suggest that the increased phosphorylation of p66shc is one of the important mediators in the impaired endothelium-dependent relaxation of aortic coarctation rats.     

Chemical suppression of a genetic mutation in a zebrafish model of aortic coarctation

Conventional drug discovery approaches require a priori selection of an appropriate molecular target, but it is often not obvious which biological pathways must be targeted to reverse a disease phenotype. Phenotype-based screens offer the potential to identify pathways and potential therapies that influence disease processes. The zebrafish mutation gridlock (grl, affecting the gene hey2) disrupts aortic blood flow in a region and physiological manner akin to aortic coarctation in humans. Here we use a whole-organism, phenotype-based, small-molecule screen to discover a class of compounds that suppress the coarctation phenotype and permit survival to adulthood. These compounds function during the specification and migration of angioblasts. They act to upregulate expression of vascular endothelial growth factor (VEGF), and the activation of the VEGF pathway is sufficient to suppress the gridlock phenotype. Thus, organism-based screens allow the discovery of small molecules that ameliorate complex dysmorphic syndromes even without targeting the affected gene directly.     

Limitations of Doppler echocardiography for the post-operative evaluation of aortic coarctation.

Doppler blood flow measurements and derived pressure differences, through the Bernoulli equation, are used in the diagnosis of aortic coarctation, a congenital stenosis distal to the left subclavian artery. Doppler velocities remain elevated at the coarctation site after successful repair of coarctation, leading to high Doppler derived pressure differences without significant arm-leg pressure differences. We studied this apparent contradiction of two diagnostic methods, in vivo using patient and control data, and in vitro using a hydraulic model. Clinical and echocardiographic data from 31 patients, aged 13.0 +/- 4.0, 10.5 +/- 4.7 yr after coarctectomy by end-to-end anastomosis, and 18 age-matched healthy subjects were reviewed. Doppler peak velocities at the aortic isthmus were elevated in patients (2.2 +/- 0.4 vs. 1.2 +/- 0.2m/s, P < 0.001), corresponding to significant Doppler differences (20 +/- 7 mmHg), however, without significant arm-leg pressure differences. In all patients, a mild anatomic stenosis could still be observed. Local stiffness was increased. The hypothesis that the less distensible surgical scar in post-coarctectomy patients leads to a significant dynamic obstruction in systole was validated in a latex model of the aorta. Rigid rings (0.5-1.5 cm), matching the unloaded aortic diameter, were mounted around the aorta. Under loading conditions, Doppler peak velocities increased by 40 +/-7%, yielding Doppler differences of 21 +/- 3 mmHg, without a significant pressure drop. An alternative expression to calculate pressure differences, using both velocity and geometric information, was validated in the model. In conclusion, post-operatively, Doppler velocities remain elevated due to a mild anatomical and significant dynamic narrowing, but the specific geometry, resembling a tubular hypoplasia rather than an abrupt stenosis, permits an almost complete pressure recovery explaining the occurrence of Doppler differences in disagreement with the negligible arm-leg pressure difference.     

Congenital cardiac defects; indications for surgical repair

The optimum ages for the operative repair of the various congenital defects have not as yet been definitely established. With certain exceptions, it has generally been the authors' preference to delay elective operations until after the age of 18 months. In the usual case, the optimum age for the closure of septal defects is believed to be three to five years. Operative relief of stenosis of the aortic or pulmonic valves, however, is related entirely to the extent of the obstruction, age not being a factor. Although the surgical treatment of coarctation of the aorta is probably best delayed beyond the period of infancy, it is the authors' belief that in the presence of extreme hypertension, cardiomegaly or cardiac failure, early resection of the aortic block should be accomplished. As to the treatment of tetralogy of Fallot, the authors' policy is to delay operation until such time as definitive repair becomes less hazardous. Patients with severe symptoms, however, are given the benefit of some form of operative relief as soon as possible. Whether this is palliative or corrective depends upon the characteristics of the individual case. Definitive diagnostic studies are of great aid in assessing the urgency of operative intervention. The fact that approximately one-third of the patients dealt with required operation at less than 18 months of age suggests that, in selected cases, these studies should be performed early in infancy.     

Diagnostic Value of Transthoracic Echocardiography in Patients with Coarctation of Aorta: The Chinese Experience in 53 Patients Studied between 2008 and 2012 in One Major Medical Center

Although aortography is well known as the “gold standard” for the diagnosis of coarctation of aorta (CoA), the method is invasive, expensive and not readily accepted by some patients. Ultrasound diagnosis for CoA is non-invasive, inexpensive, readily accepted by every patient, and can be repeated as frequently as necessary. The purpose of this presentation is to evaluate the applicability of transthoracic echocardiography for the diagnosis of CoA. The echocardiographic appearances of 53 patients with CoA who had undergone surgery during a 5-year period from January 2008 to October 2012 were analyzed retrospectively, and the results were compared with findings at surgery. Fifty-three patients with CoA include six with isolated CoA and 47 of CoA associated with other cardiac anomalies. Of the 53 operated patients, 48 were correctly diagnosed preoperatively by echocardiography, while two were misdiagnosed as interrupted aortic arch and the diagnosis were missed in three other patients. Thus the diagnostic accuracy rate was 90.6%, and the misdiagnosis rate was 9.4%. Preoperative echocardiographic evaluation offers very satisfactory anatomic assessment in most patients with CoA. It makes preoperative angiography unnecessary. Thus transthoracic echocardiography should be the first-line method for the diagnosis of coarctation of the aorta.     

CONGENITAL CARDIAC DEFECTS—Indications for Surgical Repair

The optimum ages for the operative repair of the various congenital defects have not as yet been definitely established. With certain exceptions, it has generally been the authors'' preference to delay elective operations until after the age of 18 months. In the usual case, the optimum age for the closure of septal defects is believed to be three to five years. Operative relief of stenosis of the aortic or pulmonic valves, however, is related entirely to the extent of the obstruction, age not being a factor. Although the surgical treatment of coarctation of the aorta is probably best delayed beyond the period of infancy, it is the authors'' belief that in the presence of extreme hypertension, cardiomegaly or cardiac failure, early resection of the aortic block should be accomplished. As to the treatment of tetralogy of Fallot, the authors'' policy is to delay operation until such time as definitive repair becomes less hazardous. Patients with severe symptoms, however, are given the benefit of some form of operative relief as soon as possible. Whether this is palliative or corrective depends upon the characteristics of the individual case.Definitive diagnostic studies are of great aid in assessing the urgency of operative intervention. The fact that approximately one-third of the patients dealt with required operation at less than 18 months of age suggests that, in selected cases, these studies should be performed early in infancy.     

Natural history and management of chronic aortic valve disease.

Chronic aortic valve disease involving stenosis, regurgitation or both is insidious and progressive. Severe valvular dysfunction may be present for years without symptoms, but functional deterioration is often rapid once congestive heart failure, angina or syncope with effort is present. As the severity of aortic stenosis may not be easy to assess clinically, the relative usefulness of various tests is considered in this paper. The difficulty with chronic aortic regurgitation lies not in diagnosing the problem but in detecting early left ventricular dysfunction in time to perform the surgery that can prevent further functional deterioration. Patients with significant aortic valve disease should undergo surgery when the important symptoms of dyspnea, angina or syncope with effort first appear. Surgery should also be considered in selected patients with aortic regurgitation in whom left ventricular function has diminished even without symptoms.     

Further phenotypic delineation of subtelomeric (terminal) 4q deletion with emphasis on intracranial and reproductive anatomy

Hypoplastic left heart syndrome(HLHS) refers to the abnormal development of the left-sided cardiac structures, resulting in obstruction to blood flow from the left ventricular outflow tract. In addition, the syndrome includes underdevelopment of the left ventricle, aorta, and aortic arch, as well as mitral atresia or stenosis. HLHS has been reported to occur in approximately 0.016 to 0.036% of all live births. Newborn infants with the condition generally are born at full term and initially appear healthy. As the arterial duct closes, the systemic perfusion becomes decreased, resulting in hypoxemia, acidosis, and shock. Usually, no heart murmur, or a non-specific heart murmur, may be detected. The second heart sound is loud and single because of aortic atresia. Often the liver is enlarged secondary to congestive heart failure. The embryologic cause of the disease, as in the case of most congenital cardiac defects, is not fully known. The most useful diagnostic modality is the echocardiogram. The syndrome can be diagnosed by fetal echocardiography between 18 and 22 weeks of gestation. Differential diagnosis includes other left-sided obstructive lesions where the systemic circulation is dependent on ductal flow (critical aortic stenosis, coarctation of the aorta, interrupted aortic arch). Children with the syndrome require surgery as neonates, as they have duct-dependent systemic circulation. Currently, there are two major modalities, primary cardiac transplantation or a series of staged functionally univentricular palliations. The treatment chosen is dependent on the preference of the institution, its experience, and also preference. Although survival following initial surgical intervention has improved significantly over the last 20 years, significant mortality and morbidity are present for both surgical strategies. As a result pediatric cardiologists continue to be challenged by discussions with families regarding initial decision relative to treatment, and long-term prognosis as information on long-term survival and quality of life for those born with the syndrome is limited.