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Results for “COARCTATION OF AORTA”

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At least 19 recordsLinked to original sources

Experimental myocardial hypertrophy induced by a minimally invasive ascending aorta coarctation.

Ascending aorta coarctation was produced by a minimally invasive technique in rabbits. Animal mortality was 5%. Morphometric and hemodynamic parameters were evaluated. A parabiotically isolated heart model was used to assess the hemodynamic parameters. Left ventricular weight/body weight ratio and muscle area showed clear evidence of hypertrophy when compared to control. The hemodynamic changes in the isolated heart model suggested decreased diastolic and systolic function in the coarcted group. The present model produced hypertrophy with low mortality rates as a result of its less invasive nature.

Animals↗

Na,K-ATPase and Ca-ATPase activities of the myocardial sarcolemma in aging rats after aorta coarctation: role of invertors.

In this work we used aorta coarctation as a model of myocardial hypertrophy. We studied the role of intracellular regulators of plasma membrane status-invertors-in the mechanisms of changes of membrane enzyme activities in the emergency stage of myocardial hypertrophy. We used Wistar rats of various ages: adult (6-8 months) and old (26-28 months) rats. It was shown that 4-6 days after aorta coarctation, in adult rats the activities of both Na,K-ATPase and Ca-ATPase of the sarcolemma of cardiomyocytes increased, but in old rats only the Ca-ATPase activity. Experiments with cell hybrids (cytosol of experimental rats and isolated sarcolemma of cardiomyocytes of intact rats) revealed that cytosol of cardiomyocytes of adult animals after aorta coarctation activated Na, K-ATPase and Ca-ATPase. Cytosol of old intact animals after aorta coarctation did not activate Na,K-ATPase, but activated Ca-ATPase. It was supposed that 4-6 days after aorta coarctation, intracellular regulators (invertors) activating Na,K-ATPase and Ca-ATPase of rat sarcolemma were synthesized in cytosol of adult animals. Invertors activating Na,K-ATPase did not appear after the aorta coarctation in old animals, but factors activating Ca2+-ATPase appeared. Cytosol of adult experimental rats activated Na,K-ATPase of sarcolemmas of cardiomyocytes of intact old animals. The data proved the ability of Na,K-ATPase of sarcolemma of old animals to respond to regulating factors. Based on the divergence between the results of experiments with the Na,K-ATPase and Ca-ATPase activities in old rats, it can be supposed that we were dealing with two different invertors.

Aging↗

Subclavian artery patch angioplasty. Treatment of infants and young children with aorta coarctation.

Repair of thoracic aorta coarctation in infants has had a high recurrence rate in most series. Recurrence is the result of several factors, but the type and growth of anastomosis are of primary importance. Subclavian artery patch angioplasty was used consecutively in eight children under the age of 5 years. There are six long-term survivors who have been observed for an average of 22 months. Body surface area during this time increased from a mean of 0.22 sq m preoperatively to a mean of 0.54 sq m at present. Blood pressure in the arms and legs were recorded at recent examination using an ultrasound pressure recorder. Only one patient had a substantial gradient (30 mm Hg). All survivors are asymptomatic. Use of the subclavian artery appears to allow for growth at the repair site.

Aorta, Thoracic↗

[Quality of life after surgical correction of the aorta coarctation. Retrospective analysis of a group of patients with long-term follow-up].

PURPOSE: To report on the long-term results after operation for coarctation of the aorta. METHODS: One hundred and four patients were studied, divided in four groups (G1, G2, G3 and G4), according to age at operation. Data analysed: reoperation, persistent hypertension, residual lesions, left ventricular function and ability index. RESULTS: Reoperation was frequent, mainly in G1 (60%) and G4 (29%). Resting hypertension occurred predominantly in cases operated on after the 10th year of life: 28% (G3) and 29% (G4). Exercise hypertension was found in cases operated on after the 20th year. Residual lesions were frequent: 97%, 98%, 83% and 65% (G1 to G4). Individual functional limitation was uncommon. The ability index was normal in the great majority of the patients (94%). CONCLUSION: Reoperation is frequent, particularly for recoarctation and aortic stenosis. Rest and/or exercise hypertension is common and related to delayed surgery. Aortic residual lesions are frequent. Physical limitation is uncommon. Postoperative follow-up is essential in order to detect late complications, which, usually, do not limit the individual patient.

Adolescent↗

Pharmacokinetic study of methyldopa in aorta-coarctated rats using a microdialysis technique.

The pharmacokinetics of methyldopa (12.5, 25 and 50 mg kg(-1), i.p.) was studied in anesthetized sham-operated (SO) and abdominal aorta-coarctated (ACo) rats using a microdialysis technique. A non-linear relationship between the area under the curve (AUC) and dose was observed in SO rats. However, in ACo rats the AUC showed a proportional increase with dose. Abdominal aortic coarctation produced significant differences in the estimates of clearance (Cl) and the elimination rate constant from the dialysate (K(ed)) after the administration of 50 mg kg(-1)of methyldopa (K(ed)SO, 0.31 +/- 0.09; ACo, 0.66 +/- 0.09(*)h(-1): Cl SO, 30.8 +/- 10.1; ACo, 78.6 +/- 13.3(*)mlkg(-1)min(-1);n= 6,(*)P< 0.05 vs SO). In conclusion, this study, by using a microdialysis technique, suggests that abdominal aortic coarctation seems to produce changes in the pharmacokinetics of methyldopa in rats.

Animals↗

Significant depletion of NPY in the innervation of the rat mesenteric, renal arteries and kidneys in experimentally (aorta coarctation) induced hypertension.

The distribution and concentrations of neuropeptide Y (NPY) in kidneys, renal arteries, heart, aorta, mesenteric artery and adrenal glands from aorta-ligated hypertensive rats were studied by immunocytochemistry and radioimmunoassay. Immunocytochemistry showed that in the hypertensive animals NPY-immunoreactive fibres were decreased in both kidney and renal artery, above and below the ligation, and in mesenteric arteries. The depletion of NPY-containing nerves in the kidney was more pronounced around the juxtaglomerular apparatus than in other areas of the organ. By radioimmunoassay, the concentrations of NPY immunoreactivity were significantly lower in the hypertensive animals when compared with the controls, (kidney: hypertensive 1.0 +/- 0.1; controls 2.0 +/- 0.2 pmol/g, mean +/- SEM; p less than 0.05 renal artery: hypertensive 5.0 +/- 0.8; controls 12.1 +/- 2.0; p less than 0.05 and mesenteric artery: hypertensive 8.6 +/- 1.9; 17.6 +/- 3.0; p less than 0.01). While there were no statistically significant changes in the levels of NPY immunoreactivity in the other areas studied, there was a general trend for the level to fall in the renal artery below the ligation (hypertensive 10.6 +/- 1.5; control 15.3 +/- 2.4; p greater than 0.05). It is of interest that changes were observed in the vasoconstrictor peptide NPY in this commonly used model of hypertension.

Adrenal Glands↗

Coarctation of the aorta.

Coarctation of the aorta is an important and treatable cause of secondary hypertension. The prevalence of aortic coarctation varies from 5% to 8% of all congenital heart defects. Neonates and infants, especially when they have other associated cardiac defects, may present with signs and symptoms of heart failure. Children beyond infancy are usually asymptomatic and are most often diagnosed because of a murmur or hypertension on a routine examination. Palpation of the brachial and femoral pulses simultaneously will show decreased and delayed or absent femoral pulses. On measurement of blood pressure from arms and legs, a pressure difference of more than 20 mm Hg in favor of the arms may be considered as evidence for coarctation of the aorta. The coarctation can be demonstrated on suprasternal notch two-dimensional echocardiographic views along with increased Doppler flow velocity across the coarctation site. Cardiac catheterization shows significant peak-to-peak systolic pressure gradient across the coarcted segment, and aortography demonstrates the degree and nature of the aortic narrowing. Aortic coarctation may be relieved by surgery or by balloon angioplasty; in asymptomatic patients, therapy during the ages of 2 and 5 years is suggested. Surgical relief of coarctation may be achieved by resection and end-to-end anastomosis or by subclavian flap or prosthetic path angioplasty. Although results of surgery are generally good, there are some problems with the procedure, namely, mortality, morbidity and recoarctation, particularly in neonates and young infants and development of aneurysm, paraplegia, and paradoxical hypertension. Balloon angioplasty has been used by some cardiologists with resultant relief of obstruction, but concern for development of aneurysms and arterial complications remain. Although the immediate results for surgical or balloon therapy for isolated coarctation are good, long-term prognosis is largely undetermined. Limited long-term follow-up studies suggest significantly lower survival rates compared with normal population; age at intervention and the degree and duration of hypertension before intervention may affect long-term survival.

Angioplasty, Balloon↗

Acquired coarctation of the aorta.

Coarctation of the aorta is usually caused by a congenital narrowing of the aorta. This report describes two children who developed hypertension secondary to an acquired coarctation of the aorta. In one patient the coarctation was temporally related to umbilical artery catheterization and was associated with thrombosis and aneurysmal dilatation of the aorta. In the second patient, the coarctation occurred after surgical aortotomy during the removal of an intrathoracic neuroblastoma. Patients who have interventional damage to the aorta should be periodically examined for the appearance of a coarctation. Although an acquired coarctation of the aorta is an infrequent complication of invasive or surgical procedures, it should be identified since it represents a remediable cause of hypertension in children.

Aortic Coarctation↗