Successful Repair Of Coarctation Research Articles

Enhanced resting left ventricular filling in patients with successful coarctation repair and exercise-induced hypertension

M-mode and Doppler echocardiographic analyses of left ventricular (LV) shortening and filling were performed in 50 patients who underwent coarctectomy (median follow-up 9.5 years) and in 16 athletes in a control group before an exercise stress test with upright bicycle ergometry was performed. Thirty-two of 50 patients and 18 of 50 patients had a normotensive and hypertensive response to exercise, respectively. Preexercise echocardiographic data were compared among the control, normotensive, and hypertensive patient groups. LV peak filling rates ( dD/ dt, diastole) were increased in the hypertensive group (18.3 ± 3.5) compared with those in the normotensive group (14.4 ± 3.2; p < 0.001) and the control group (13.6 ± 2.8; p < 0.001). LV shortening was enhanced in the coarctectomy group compared with that in the control group. A higher aortic isthmus Doppler gradient at peak exercise was not found in the hypertensive group compared with that in the normotensive group. Therefore patients with successful coarctectomy in childhood have enhanced LV shortening and relaxation at rest. Demonstration of enhanced LV peak filling rates may help identify patients at risk for exercise-induced hypertension. (Am Heart J 1997;134:1082-8.)

Pregnancy in women with coarctation of the thoracic aorta

In summary, significant coarctation of the aorta during pregnancy in the unoperated setting carries an increased risk of morbidity and mortality both to mother and fetus and therfore, is contraindicate until adequate surgical intervention has been carried out. Previously operated patients need to be carefully screened fromthe cardiovascular stand-point before pregnancy. The risk of pregnancy is substantially reduced after successful coarctation repair, however, it is not negligible.

Management of Arch Hypoplasia After Successful Coarctation Repair

Background. Pronounced arch obstruction can be seen after a well-repaired coarctation, and this probably results from the failure of a somewhat hypoplastic arch to grow or from clamp injury at the time of the initial repair, or from both causes. Because of mediastinal adhesions and minimal collateral circulation, use of extraanatomic bypass grafts appears to be the preferred approach.Methods. Six children or young adults presented with arch obstruction over a 3-year period. Their mean age was 13.5 ± 4 years, and the mean interval from the time of the initial repair was 10 ± 4 years. The mean age of the patients at the time of the initial repair was 3.2 ± 5 years. Symptoms included exertional headache and chest pain. The mean systolic gradients, as shown by echocardiography and cardiac catheterization, were 34 ± 7 mm Hg and 33 ± 6 mm Hg, respectively. Repair was accomplished through a midsternotomy using a polytetrafluoroethylene patch placed in the concavity of the arch, which extended from the ascending to the descending aorta. Dissection was kept close to the aorta and arch to minimize injury to the phrenic and recurrent laryngeal nerves. Cardiopulmonary bypass and moderate hypothermia (25° to 27°C bladder temperature) without circulatory arrest were used.Results. All patients were discharged home 4 to 20 days postoperatively (mean, 7 ± 6 days). All patients were found to be normotensive at a mean follow-up of 1.3 ± 1 years. Postoperative echocardiograms, which were obtained in all patients, revealed no residual gradients. Exercise blood pressure was evaluated in 2 patients and found to be normal.Conclusions. Transsternal arch enlargement using cardiopulmonary bypass and moderate hypothermia without circulatory arrest is an attractive and safe approach for the treatment of arch obstruction after coarctation repair. Unlike the use of extraanatomic bypass grafts, it allows complete relief of the obstruction, unhampered aortic growth, the minimal use of foreign material, and a repair that is protected deep within the mediastinal space.(Ann Thorac Surg 1997;63:975–80)

COLLAGEN SECRETION AND PHENOTYPE OF SMOOTH MUSCLE CELLS FROM COARCTED HUMAN NEONATAL AORTA. † 160

Patients who have undergone successful repair of coarctation of the aorta(COA) at any age have been shown to have persistent abnormalities of the pre-coarctation vascular bed, including increased stiffness and diminished vasodilation. These changes contribute to increased morbidity and mortality from cardiovascular causes. We sought to investigate whether these changes in aortic compliance resulted from intrinsic abnormalities in the phenotype or the types of collagen produced by the smooth muscle cells of the aortic media in these patients. A higher collagen I/III ratio reflects a greater degree of stiffness of the vessel, where type I collagen lends rigidity and type III contributes to elasticity. Smooth muscle cells from the media of the pre-COA, coarctation and post-COA tissue resected from eight patients were isolated by dissection and grown in culture. The pattern of expression of alpha smooth muscle actin (SMA) was determined by immunostaining of cells in monolayer and immunoblotting of cell lysates. Secretion of collagen types I and III was determined by isolation of radiolabeled collagen from the media of confluent plates, pepsin digestion, and separation of collagen types I and III by polyacrylamide gel electrophoresis. The ratio of collagen I/III was determined by densitometry.

Peripheral blood flow responses to exercise after successful correction of coarctation of the aorta

The purpose of this study was to characterize peripheral flow kinetics in response to progressive discontinuous maximal exercise in 10 patients who underwent repair of coarctation of the aorta and 11 age-matched healthy adolescents. An impairment of leg blood flow has been suggested on the basis of exaggerated femoral muscle lactate accumulation in patients with successful repair of coarctation. Few data are available describing blood flow kinetics of the exercising leg in such patients. Duplex ultrasound provided transcutaneous measurements of peak systolic and end-diastolic flow velocities of the femoral, humeral and renal arteries at rest and immediately after mild, moderate and maximal exercise intensities for computation of mean velocity, resistance index and femoral blood flow. Femoral mean velocity and femoral blood flow increased linearly with exercise intensity in both groups, but the slope of this increase was significantly lower in patients. Similarly, humeral mean velocity increased significantly less in patients than in control subjects. Femoral resistance index sharply decreased from that at rest (patients [mean +/- SE] 1.4 +/- 0.04; control subjects 1.4 +/- 0.03) to mild exercise intensity in both groups (patients 0.69 +/- 0.03; control subjects 0.72 +/- 0.03). A further decrease was observed at maximal exercise in patients (0.60 +/- 0.04, p = 0.08) but not in control subjects (0.69 +/- 0.02). These observations suggest that despite a greater exercise-induced femoral vasodilation, patients with successful correction of coarctation of the aorta demonstrate an impaired lower limb blood flow in response to strenuous dynamic exercise. In the absence of stenosis at rest, this alteration could result from exaggerated flow turbulence in the descending aorta distal to the site of correction because of loss of elasticity at the site of the resection of the coarcted segment.

Coarctation of the aorta. Repair with polytetrafluoroethylene patch aortoplasty.

The first successful surgical repair of coarctation of the aorta (CoAo) was performed in 1944, but during the years that followed a high incidence of recoarctation was seen, ranging from 20% to 86%. In response to that problem, the patch aortoplasty was introduced in 1957; however, true aneurysms were found in the aortic wall opposite the patch after Dacron patch aortoplasty, particularly when the coarctation ridge was excised. The purpose of our review was to evaluate the results of patch aortoplasty for CoAo using a relatively new material, polytetrafluoroethylene (PTFE), and an operative technique that does not involve resection of the coarctation ridge. Between 1979 and 1993, 125 infants and children underwent PTFE patch aortoplasty for CoAo; 111 of the procedures were primary repairs, and 14 were reoperations. Diagnoses were isolated CoAo (96 patients), CoAo and ventricular septal defect (15 patients), and CoAo with complex intracardiac anomaly (14 patients). Patient age at the time of repair ranged from 4 days to 17 years (mean age, 5.1 +/- 4.5 years). There were no instances of intraoperative mortality or paraplegia. There were 4 deaths from 10 to 40 days postoperatively, all in neonates (mean age, 33 days) who received additional intracardiac procedures for complex associated anomalies. Follow-up has ranged from 6 months to 12.5 years (mean, 4.5 +/- 3.2 years). All children had postoperative chest roentgenograms, 80 (66%) patients have had a postoperative echocardiogram and 16 (13%) a cardiac catheterization. One patient had successful repair of a false aneurysm 4 months postoperatively. No patient has developed a late true aneurysm. Of the patients < 1 month of age at the time of CoAo repair (12 patients), 6 patients had recurrent CoAo (gradient > 20 mm Hg) compared with only 4 recurrences in 97 patients > 1 month of age at the time of repair (P < .001). For children > 1 year of age, PTFE patch aortoplasty remains our procedure of choice for CoAo repair because of the low mortality rate, low recoarctation rate, and absence of late true aneurysms. We have stopped using this technique for infants < 1 month of age because of the high recurrence rate.

Persistent hyperdynamic cardiovascular state at rest and during exercise in children after successful repair of coarctation of the aorta

Objectives. The purposes of this study were to evaluate left ventricular performance and contractility at rest and during exercise to determine mechanisms and correlates for alterations in performance and blood pressure in pediatric patients after successful repair of coarctation of the aorta.Background. Blood pressure and left ventricular function are elevated in children despite successful repair. The mechanisms for these changes are not understood.Methodes. Thirty asymptomatic pediatric patients with successful coarctation repair (mean age [± SD] 12.5 ± 4 years) underwent echocardiographic determination of left ventricular mass, perforsion), afterload (end-systolic wall stress), contractility (velocity of circumferential fiber shortening/wall stress relation) and Doppler gradient at rest and during exercise. Data were compared with those of 24 control subjects (mean age 21.0 ± 4 years). Because of the age discrepancy between groups, age-dependent echocardiographic data were indexed by body surface area.Results. The mean age at operation was 5 ± 4 years, and the average follow-up period was 7.5 ± 3 years. The average blood pressure gradient between upper and lower limbs was 4 mm Hg. Left ventricular mass was higher in the postoperative group than in the control group (1.58 vs. 1.31 g/ht2.7, p = 0.04), as were values at rest for performance (44% vs. 31%, p = 0.0001), preload (3.9 vs. 3.7 cm/body surface area0.5), indexed systolic blood pressure (1.05 vs. 0.91, p = 0.0001) and contractility (0.23 vs. −0.05 circumferences/s, p = 0.001). Afterload was lower at rest (36 vs. 52 g/cm2, p = 0.0004). These differences between groups persisted during and after exercise. Contractility underwent an exaggerated increase after exercise in the postoperative group.Conclusions. Left ventricular performance in children after coarctation repair is higher at rest and during exercise than in control subjects as a result of higher preload and contractility and lower afterload. These changes may be due to associated hypertrophy. Persistent postoperative hypertension may be due to a hyperdynamic, hypercontractile state caused by residual gradients manifested only during exertion.

Arterial reactivity is significantly impaired in normotensive young adults after successful repair of aortic coarctation in childhood.

Despite successful repair of coarctation of the aorta in childhood, adult survivors often have hypertension at rest or on exercise, and their life expectancy is shorter than normal because of premature coronary and cerebrovascular disease. This may be related to persistent structural and functional arterial abnormalities after surgery. Using high-resolution ultrasound, we studied the right brachial arteries of 25 normotensive young adults who had undergone successful repair of coarctation in childhood (mean age at repair, 62 months; range, 0 to 167 months, including 8 patients operated on in infancy; mean age at study, 19 years; range, 14 to 27 years) and 50 age- and sex-matched control subjects. We assessed the degree of reactive hyperemia (RH) produced after distal cuff occlusion and release and the changes in arterial diameter in response to RH (with increased flow causing endothelium-dependent dilation) and to glyceryltrinitrate (GTN, an endothelium-independent dilator). The response of the right femoral artery to GTN was also measured in 12 coarctation subjects and 12 control subjects. Studies were performed 13.7 years (range, 7 to 21 years) after surgery. RH was significantly lower in coarctation subjects (343 +/- 130% versus 482 +/- 147%), as were endothelium-dependent dilation (3.8 +/- 3.3% versus 8.8 +/- 3.6%) and GTN response (13.3 +/- 6.0% versus 20.5 +/- 6.1%) (P < .001 for each), reflecting abnormal dilatory capacity in both the resistance and conduit arteries. In contrast, GTN-induced dilation in the femoral arteries was similar to that in control subjects (9.5 +/- 2.6% versus 10.1 +/- 4.1%, P = .70). On multivariate analysis, GTN response and systolic blood pressure at peak exercise were inversely correlated (r = -.52, P = .04). Vascular responses were not related to the age at repair. Despite successful repair of coarctation in childhood, arterial dilation is significantly impaired in the precoarctation vascular bed of healthy young adults. This may be an important contributor to exercise-related hypertension and late morbidity or mortality.

Non-invasive evaluation of left ventricular systolic function late after coarctation repair: influence of early vs late surgery.

The study was designed to assess non-invasively the long-term effect of coarctation repair on systemic blood pressure, left ventricular (LV) muscle mass (LMM) and LV systolic function. Blood pressure and pressure gradients across the coarctation site were measured at rest and during exercise. LV systolic function and LMM were assessed by echocardiography. Twenty-eight patients late after successful coarctation repair were divided according to their age at surgery into two groups: group 1: < 1 year (10 days-12 months, mean 0.2 years) and group 2: > 1 year (1-19 years, mean 9.7 years). A group of age- and sex-matched patients with normal LV function served as controls. LMM was increased late postoperatively in both groups irrespective of the age at surgery and was correlated significantly with the elevated systolic blood pressure and the residual pressure gradient at exercise. End-systolic wall stress was normal at rest and the stress/velocity relationship revealed normal contractility in all patients. Despite successful operation of aortic coarctation, residual LV hypertrophy persists 2 to 19 years after surgery irrespective of the age at surgery. LV systolic function is normal. Hypertrophy can be explained by the residual arm-leg pressure gradient during exercise which persists even after successful repair.

Ambulatory blood pressure monitoring and left ventricular mass and function after successful surgical repair of coarctation of the aorta

Late cardiovascular morbidity and mortality remain significant despite apparently successful surgical repair of aortic coarctation. Alterations in cardiac function have been reported in normotensive patients who have had successful repair, the reasons for which remain unclear. This study addresses the relation between ambulatory blood pressure measurements and alterations in left ventricular performance in 20 patients with normotension at rest after successful repair of aortic coarctation. Exercise testing, ambulatory blood pressure monitoring and two-dimensional echocardiographic studies in 13 boys and 7 girls (mean age 14.2 ± 2.31 and 14.7 ± 3 years, respectively) who had no evidence of recoarctation were compared with the findings in 20 matched control subjects.No difference was found in systolic blood pressure at rest or peak exercise between patients and control subjects. Male patients developed a significant arm/leg gradient at peak exercise. Systolic ambulatory blood pressure was higher throughout the day in the male group. In the female group, systolic blood pressure was higher only during sleep. No difference was found in diastolic blood pressure or heart rate. The transverse aortic arch was smaller and the left ventricular mass greater in all patients. The relation of wall stress to rate-corrected velocity of shortening was 2 SD above normal in 8 of the 20 patients, suggesting that some have enhanced contractility. The E/A ratio on the atrial echocardiogram was significantly reduced in the patient group.Successfully treated patients who are normotensive at rest after operation are still at risk for developing end organ damage, which is probably explained by incipient mild hypertension documented by ambulatory blood pressure monitoring.

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

Fifteen children and adolescents who had repair of coarctation of the aorta before age 15, who were not hypertensive at rest, and who had resting arm-leg blood pressure gradients of <20 mm Hg underwent noninvasive evaluation of left ventricular structure and function, aortic stiffness, and residual coarctation as well as bicycle exercise testing. These results were compared with those in 15 age- and sex-matched control subjects. The mean resting age-related systolic blood pressure percentiles (63% versus 46%), transverse aortic stiffness measured by the elastic modulus (Ep) (42.1 versus 23.2 kPa), stiffness index beta (β) (3.66 versus 2.17), echocardiographic left ventricular fractional shortening (0.42 versus 0.36), left ventricular mass index (99.3 versus 81.0 gm/m 2), maximum exercise right arm systolic blood pressure (173 versus 156 mm Hg), and exercise arm-leg blood pressure gradient (35 versus 6 mm Hg) were significantly increased in the coarctectomy patients compared with controls. Univariate correlations in the coarctectomy group showed significant relationships of residual aortic narrowing with left ventricular mass index ( r = 0.68, p < 0.01) and resting systolic blood pressure percentile for age ( r = 0.55, p < 0.05). Residual aortic narrowing did not significantly correlate with aortic stiffness, resting blood pressure gradient, or exercise blood pressure gradient. Neither left ventricular mass index nor resting systolic blood pressure percentile significantly correlated with age of repair or years after repair. These results demonstrate persistent abnormalities in aortic stiffness and left ventricular mass and function after successful repair of coarctation of the aorta in childhood and adolescence. Mild degrees of residual aortic narrowing may affect resting blood pressure and left ventricular mass. Elevated blood pressure and blood pressure gradients between upper and lower extremities during exercise may be a reflection of increased arterial stiffness in the upper body as well as mild persistent coarctation.

Atenolol therapy for exercise-induced hypertension after aortic coarctation repair

After successful repair of coarctation of the aorta in childhood, exercise-induced upper body systolic hypertension is well documented. Beta blockade has been shown to reduce the arm/leg gradient in untreated coarctation of the aorta; treatment before coarctation repair has decreased paradoxical hypertension after repair. Ten patients with successful surgical repair of coarctation, defined as a resting arm/leg gradient of ≤18 mm Hg, were evaluated by treadmill exercise before and after β blockade with atenolol. Mean age was 5.5 years at repair and 18 at study. At baseline evaluation, systolic blood pressures at termination of exercise ranged from 201 to 270 mm Hg (mean 229 mm Hg). Arm/leg gradients at exercise termination ranged from 30 to 143 mm Hg (mean 84). Followup treadmill exercise studies were performed after β blockade. Upper extremity systolic pressures at exercise termination were normalized in 9 of 10 patients. Maximal systolic blood pressure recorded at exercise termination ranged from 163 to 223 mm Hg (mean 196 mm Hg, p < 0.005). Arm/leg gradient at termination of exercise also decreased significantly to a mean of 51 mm Hg (p < 0.05). No patient had symptoms on atenolol and exercise endurance times were unchanged. The study results in this small series suggest that cardioselective β blockade can be used to treat exercise-induced upper body hypertension effectively after surgical repair of coarctation. Because a high incidence of premature cardiovascular disease has been well documented after satisfactory surgical repair, the findings are of importance for this group of postoperative patients.

Altered systolic and diastolic function in children after “successful” repair of coarctation of the aorta

We investigated whether left ventricular (LV) structural or functional abnormalities persist in children on long-term follow-up after successful correction of coarctation of the aorta. Two-dimensional directed M-mode and Doppler echocardiographic examinations were performed on 11 such subjects and 22 age-matched control subjects. Digitized tracings were made from M-mode recordings of the LV and Doppler mitral valve inflow recordings to measure septal, posterior wall, and LV dimensions, LV mass, shortening fraction, peak shortening and lengthening velocities, diastolic filling time, peak E velocity, peak A velocity, and velocity time integrals. Despite group similarities in age, body size, and systolic blood pressure, greater fractional shortening ( p = 0.0001), indexed peak shortening velocity ( p < 0.001), and greater LV mass index ( p < 0.05) were seen in the coarctation group in the face of lower LV wall stress ( p = 0.0001). LV mass index correlated with the resting arm-leg gradient, which ranged from −4 to +10 mm Hg. The coarctation group had decreased early filling ( p < 0.006) with compensatory increased late diastolic filling ( p < 0.05). Diastolic filling abnormalities were prominent in the older coarctation subjects and were related to both systolic blood pressure ( p < 0.001) and LV mass index ( p < 0.01). Despite apparently successful repair of coarctation of the aorta, persistent alterations in both systolic and diastolic LV function and LV mass are present in children at long-term follow-up, which are related to the resting arm-leg gradient. We speculate that these small measured arm-leg gradients represent persistent alterations in flow, which may result in LV hypertrophy and hyperkinesia.

Long-term systemic hypertension in children after successful repair of coarctation of the aorta

The mechanisms responsible for long-term hypertension in children after successful repair of coarctation of the aorta have not yet been determined. We measured plasma renin activity and aldosterone, adrenalin, and noradrenalin concentrations both under basal conditions and in response to standing and treadmill exercise in 24 normal normotensive children, 16 normotensive postcoarctectomy children, eight hypertensive postcoarctectomy children, and seven children with essential hypertension. Exercise-induced changes in plasma renin activity, aldosterone, adrenalin, and noradrenalin were comparable in the four groups in spite of a significantly greater increase in systolic blood pressure in the children with hypertension. In response to standing, the plasma concentration of noradrenalin increased significantly in normotensive but not in hypertensive children. Hyperresponse of blood pressure to exercise in hypertensive postcoarctectomy children and children with essential hypertension is not related to abnormalities in the sympathetic nervous system or the anglotensin-aldeosterone axis. Hypertension could be related to primary baroreceptor alterations, to structural changes in the arterial wall, or both. Twenty percent of normotensive postcoarctectomy children had a blood pressure hyperresponse to exercise and an abnormal noradrenalin response to standing similar to that seen in the hypertensive children. Follow-up of children after coarctectomy may elucidate whether these two abnormalities are indicators of an increased risk of developing long-term recurrent hypertension.

Status of patients 5 or more years after correction of coarctation of the aorta over age 1 year.

In this retrospective study, we reviewed the records of patients who had coarctectomies at the University of Virginia Hospital after 1 year of age. Follow-up data for 5 years or more after surgery were available for 52 patients. Data from 23 similar patients from the Medical College of Virginia brought the total postoperative sample size to 75. The blood pressure of this group of patients did not differ significantly from that of the population at large. We conclude that successful repair of coarctation of the aorta in childhood or early adolescence does not lead to a higher-than-expected incidence of resting hypertension in childhood.

A successful surgical repair of coarctation of the persistent fifth aortic arch associated with atresia of the fourth aortic arch.

A successful surgical repair of coarctation of the persistent fifth aortic arch associated with atresia of the fourth aortic arch.

Left Aortic Dissection following Repair of Coarctation of the Aorta: The Contribution of Abnormal Hemodynamics to Medial Degeneration

Although aortic dissection is a frequent complication of coarctation of the aorta, its occurrence after successful repair has not been previously reported. It has been assumed, therefore, that alleviation of the hypertension prevents progressive aortic changes leading to dissection or rupture. This paper presents two patients in whom aortic dissection or rupture occurred despite previous successful coarctation repair. Abnormal hemodynamics in coarctation may be secondary to hypertension, changes in pulsatile flow, dilatation of the ascending aorta and/or a bicuspid aortic valve. Only the first two factors are abolished with surgical repair. The contribution of abnormal hemokinetics in the propagation of aortic disruption of other etiologies is discussed.