Surgical Correction Of Aortic Coarctation Research Articles

Repair of aortic coarctation using temporary ascending to descending aortic bypass in children with poor collateral circulation.

Aortic coarctation can now be repaired surgically with excellent results. Even though rare, injury to the spinal cord resulting in paraplegia remains a major concern. Preoperative evaluation showing the absence of collateral circulation is valuable in order to introduce protective actions. This report describes our experience using a temporary bypass from the ascending to the descending aorta bypass in children undergoing surgical correction of aortic coarctation in the setting of poorly developed collateral circulation. Between 1990 and 2002, we undertook direct surgical repair in 56 patients with isolated aortic coarctation, 20 as neonates, 11 as infants, and 25 during childhood. From 1998 onwards, we introduced preoperative evaluation of the collateral circulation with magnetic resonance imaging. From that time, we placed a temporary bypass from the ascending to the descending aorta, using a polytetrafluoroethylene tube of 4 to 8 mm diameter, whenever distal pressures were shown to be 25 mmHg or less after test clamping, or when magnetic resonance imaging revealed absence of collateral circulation. We found excellent correlations between the direct intra-operative measurements of distal pressure and the findings at magnetic resonance imaging. Following introduction of the temporary bypass, we observed no neurological complications, nor were there any complications related to bypass. Freedom from restenosis was 96%. Preoperative magnetic resonance imaging, therefore, can accurately visualize poor collateral circulation in children with aortic coarctation. The use of a temporary bypass can possibly eliminate the risk of neurological sequels following direct repair of coarctation in children with poorly developed collateral circulation. The temporary bypass is both easy to apply and safe.

Predictors of aneurysmal formation after surgical correction of aortic coarctation

Predictors of aneurysmal formation after surgical correction of aortic coarctation

Aortic coarctation reconstructed by resection and homograft replacement in the 1950s: long-term outcome 40 years after operation

Since the first successful repair of aortic coarctation by Dr Clarence Crafoord in 1945, there are few data regarding late follow-up of homografts in this position. Between 1957 and 1959, 7 patients underwent surgical correction of aortic coarctation by Professor József Kudász at the Department of Cardiovascular Surgery, Semmelweis University, using freeze-dried aortic homograft. We were able to locate 4 of these patients and found no significant complications due to the operation. We report on this 40-year follow-up of implanted aortic homograft.

Predictors of aneurysmal formation after surgical correction of aortic coarctation

ObjectivesWe sought to identify the predictors of aneurysmal formation after surgical correction of aortic coarctation. BackgroundIn 9% of patients, aneurysms develop late after corrective surgery of coarctation of the aorta, with a 36% mortality rate if left untreated. However, the predictors of postsurgical aneurysmal formation are unknown. MethodsOf 25 aortic aneurysms requiring corrective surgery 152 ± 78 months after the initial coarctation repair, 8 were located in the ascending aorta (type A) and 17 at the site of previous repair (local type). Seventy-four patients without progression of the aortic diameter within 189 ± 71 months after coarctation repair were used for categorical data analysis in an attempt to identify the predictors of postsurgical aneurysmal formation. ResultsAdvanced age at coarctation repair (p = 0.004) and patch graft technique (p < 0.0005) independently predicted local aneurysmal formation. Type A aneurysm was univariately associated with the presence of a bicuspid aortic valve (p = 0.02), advanced age at coarctation repair (p = 0.044) and a high preoperative peak systolic pressure gradient of 74 ± 21 mm Hg (p = 0.041). Conversely, multivariate analysis confirmed only the presence of a bicuspid aortic valve (p = 0.015) as an independent predictor of type A aneurysm. Receiver operating characteristic curve analysis revealed that 72% of patients with a postsurgical aneurysm had an operation at age 13.5 years or more, whereas 69% with no postsurgical aneurysm had an operation at a younger age. ConclusionsUse of the patch graft technique and late correction of coarctation can predict aneurysmal formation at the site of coarctation repair, although patients with a bicuspid aortic valve may be at risk for an aneurysm developing in the ascending aorta, particularly after late repair of aortic coarctation with high preoperative pressure gradients.

Ambulatory blood pressure monitoring in children with aortic coarctation and kidney transplantation

Background: Ambulatory blood pressure monitoring (ABPM) has been found to be of significant importance in clinical practice because numerous blood pressure (BP) measurements may be made throughout the 24-hour period.Objective: To assess the clinical utility of ABPM in children with secondary hypertension.Methods: We studied 37 patients (21 boys and 16 girls), with a mean age of 16.4 ± 4.1 years, after kidney transplantation and 38 patients (27 boys and 11 girls), with a mean age of 10.2 ± 2.1 years, after surgical correction of aortic coarctation. Data, expressed as mean ± SD, were analyzed after dividing the patients into 4 groups. Group A consisted of 25 patients receiving antihypertensive therapy; group B included 12 patients not receiving antihypertensive therapy. Group C included 25 patients operated on before 3 years of age (8 ± 7 months of age); group D included 13 patients operated on after 3 years of age (74 ± 29 months of age).Results: In groups A and B, casual BP measurement showed that 16 of 37 patients (43%) were hypertensive; 24-hour ABPM detected a larger number of patients who were hypertensive (23 of 37, 62%); there were 18 in group A and 5 in group B. In groups C and D, casual BP measurement identified 6 of 38 (15%) patients as hypertensive, whereas 24-hour ABPM again identified a higher number (13 of 38, 34%).Conclusions: Our findings confirm that 24-hour ABPM is more sensitive than casual BP in detecting abnormal BP in patients at high risk for secondary hypertension.

Hypoplastic aortic arch morphology pertinent to growth after surgical correction of aortic coarctation

Whether a hypoplastic transverse arch will grow after successful coarctectomy remains controversial. We studied 15 coarctation specimens with hypoplastic transverse arch. Eight patients were less than 1 month old and 7 were between 1 and 3 months. The diameter and length of the various segments of the aortic arch were measured. The number of elastin lamellae was determined histologically. Collagen density was quantified with a microdensitophotometer. Using immunohistochemistry, we determined alpha-actin-positive smooth muscle cells in the media of the ascending aorta and the hypoplastic transverse arch. Despite a hypoplastic transverse arch, the ascending and descending aorta grew. The absolute number of elastin lamellae in the hypoplastic transverse arch was low, but when expressed as a ratio versus its diameter, this number was high (p < 0.05). Collagen density showed high absolute values in the descending aorta. In the older group, 4 of 7 showed no staining for alpha-actin in the hypoplastic transverse arch, whereas under 1 month of age, only 2 of 8 cases were negative. The hypoplastic transverse arch is characterized by a relatively high number of elastin lamellae. Fewer alpha-actin-positive cells in the hypoplastic transverse arch occur in older specimens, which could indicate a diminished potential growth.

Surgical repair of an aortic coarctation in a patient after treatment with extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) is a lifesaving treatment for neonates who have severe respiratory failure that does not respond to maximal conventional therapy. A consequence of venoarterial ECMO is the sacrifice of the right common carotid artery. Evaluation of the impact of a single carotid artery in babies treated with ECMO concerns mostly long-term neurodevelopmental outcome. The authors encountered a peculiar problem caused by a single carotid artery in a post-ECMO patient during the surgical correction of aortic coarctation with hypoplastic distal aortic arch. For patients with a confirmed cardiac malformation that necessitates future surgical repair and for whom ECMO support is required, reconstruction of the right common carotid artery should be considered. Veno-venous ECMO is an alternative solution if this approach is not contraindicated because of the patient's clinical condition. Patients with congenital diaphragmatic hernia have a higher incidence of cardiac malformations; therefore, careful cardiological attention is required. Anomalies masked by pulmonary hypertension also must be considered.

Effects of captopril on renal function before and after surgical correction of aortic coarctation

McQil~~Oloup:CARDICYI-HORACICSURGERY: Ray C.-J. Chiu, MD (Principal Investigator), Jonah N.K. Odim, MD (Co-ordinator), Peter E. Blundell, MD CARDIOLOGY: John H. Burgess, MD, James A. Steward, MD (Echocardiography), Mark A. Rabinovitch, MD (Radionuclide Studies). PLASTIC SURGERY: H. Bruce Williams, MD. ANESTHESIOLOGY: Richard J.S. Robinson, MD, D.T. Tmong, MD. SOCIAL WORK: Aylene Templeton, MSW NURSE CO-ORDINATOR: Lynne Fetterley, RN. PHYSIOTHERAPY: Ann J. Lu, phT. RESEARCH ASSISTANT: Caroline Desrosiers Clark, B.Sc.

Preoperative and postoperative renin levels in coarctation of the aorta.

We studied plasma renin activity (PRA) in eight children before and after surgical correction of aortic coarctation. These eight children underwent a combination of low-sodium diet and diuresis before surgery, and PRA was measured shortly thereafter. Thirty-two to 51 months after successful surgical correction, PRA was measured again. The mean PRA was 21.4 +/- 1.3 ng/ml/hour (+/- SD) preoperatively and 5.5 +/- 1.5 ng/ml/hour postoperatively. These findings provide further evidence of the significance of increased renin-angiotensin activity in patients with aortic coarctation.

Changes in plasma catecholamines and dopamine beta-hydroxylase after corrective surgery for coarctation of the aorta.

In six patients within 12 hours of surgical correction of aortic coarctation there was a 750% increase in plasma noradrenaline concentrations accompanied by an increase in systolic and diastolic blood pressures. The magnitude of the postoperative increase in noradrenaline concentrations was related to the preoperative level of the pressure gradient across the coarctation. Six months after operation plasma noradrenaline concentrations were still significantly elevated. In nine patients who underwent other types of major surgery there was a small increase in plasma noradrenaline concentrations and a return to levels within the normal range within 24 hours. Various explanations for the rise in plasma noradrenaline concentrations are considered. In particular the possibility is raised that after surgical correction of aortic coarctation the increased levels indicate a marked increase in sympathetic nervous system activity; this may be mediated by baroreceptor mechanisms and may persist for up to six months after surgery.

Differences in muscle blood flow in upper and lower extremities of patients after correction of coarctation of the aorta.

Using the method 133Xe clearance we investigated blood flow and calculated vascular resistances simultaneously in the muscles of the upper and lower extremities in 58 patients following successful surgical correction of aortic coarctation carried out at age 11.5 (+/- 2.9) years. The interval from operation to investigation was 11.5 (+/- 4.5) years. Resting and maximal ischemic exercise blood flows in the upper extremity were decreased and the duration of maximal blood flow was shortened. Values recorded from the lower extremities did not differ from normal controls. The difference between upper and lower extremities was statistically significant. Vascular resistance during maximal blood flow was higher in the upper extremities than in the lower. Differences between upper and lower extremities did not change after vasodilation elicited by amyl nitrite. The degree of differences was not dependent upon the age at operation, the age of the patients at investigation, or on the time interval between operation and investigation.

Surgical correction of aortic coarctation in children.

Flavopiridol is a broad-spectrum inhibitor of cyclin-dependent kinases (cdks) and represents the first in this anticancer class to enter clinical trials. In anticipation of the likelihood that, as with other cancer drugs, acquired resistance may limit the drug9s efficacy, an acquired resistance model has been established by in vitro drug exposure of the human colon carcinoma cell line HCT116. This stably resistant line, possessing 8-fold resistance to flavopiridol, showed a lack of cross-resistance to the anticancer agents etoposide, doxorubicin, paclitaxel, topotecan, and cisplatin, and notably to other chemical classes of cdk inhibitors: the aminopurines roscovitine and purvalanol A, 9-nitropaullone, and hymenialdisine. Resistance did not seem to be related to differences in the levels of multidrug resistance drug efflux proteins, P-glycoprotein, and MRP1. Moreover, there were no changes in overall drug accumulation between the resistant and sensitive cell lines. Flavopiridol induced cell cycle arrest, apoptosis, and inhibition of retinoblastoma gene product phosphorylation on serine 780 in both parental and resistant lines, but the latter required 8-fold higher concentrations to achieve these effects. Cyclin E protein levels and cyclin E-associated kinase activity were increased in the resistant line, suggesting that overexpression of cyclin E may be the mechanism of resistance to flavopiridol. However, transfection of cyclin E to increase expression of this protein did not result in an increase in resistance to flavopiridol. Thus, up-regulation of cyclin E alone does not seem to cause resistance to this cdk inhibitor.

Electroconvulsive therapy following surgical correction of aortic coarctation by implantation of an aortic isograft; a case history.

Electroconvulsive therapy, producing grand mal seizures, has been successfully given to a patient with a 6-cm. aortic isograft of one year without evident injury to the isograft and with marked psychological benefit to the patient.