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Biomedical subjects

J L Gibbs

Publications and source records attributed to J L Gibbs.

At least 19 recordsLinked to original sources

Severe pulmonary stenosis and interruption of the aortic arch.

A case of severe pulmonary stenosis associated with a subpulmonary ventricular septal defect and interruption of the aortic arch is described in a 5-month-old girl. This combination defies explanation by current theories of the development of obstructive abnormalities of the aortic arch secondary to reduced aortic flow during fetal life, and, to the best of our knowledge, is the first reported case with this particular association.

Angiography

Anaemia in children following cardiac transplantation: treatment with low dose human recombinant erythropoietin.

Anaemia is common in children following cardiac transplantation. In a series of 5 children with anaemia beyond the immediate post-operative period one had a hypochromic, microcytic anaemia which corrected with oral iron. The other four had normochromic, normocytic anaemias unresponsive to iron or folate supplementation and associated with inappropriately low levels of erythropoietin. Subcutaneous administration of low dose human recombinant erythropoietin to these four patients resulted in correction of their anaemia. Our findings suggest that erythropoietin deficiency is an important cause of anaemia in transplant recipients and should be sought in cases of anaemia refractory to conventional haematinic therapy. In cases of proven erythropoietin deficiency, treatment with erythropoietin is effective, acceptable to patients and preferable to repeated blood transfusion.

Adolescent

Stenting of the arterial duct: a new approach to palliation for pulmonary atresia.

OBJECTIVE: To assess the possibility of maintaining ductal patency in neonates with complex pulmonary atresia by percutaneous implantation of balloon expandable stents. PATIENTS: Two duct-dependent neonates with long segment pulmonary atresia, right sided aortic arch, and left sided arterial duct. RESULTS: Stents with final diameter of 3.5 or 4 mm and initial length of 7 or 15 mm were successfully positioned in the arterial duct. Two stents were required in one child and four in the other in order to stent the entire length of the duct. After the procedures the ducts remained widely patent and arterial oxygen saturations remained above 80%. Complications of the procedures included perforation of a peripheral pulmonary artery and cardiac perforation, both caused by guide wire manipulation. Both babies died suddenly, one at five weeks, and the other at nine days after successful stenting of the duct. Both ducts were patent at necropsy; the exact cause of one death was not clearly defined, but the second seemed to be caused by pneumococcal septicaemia. CONCLUSIONS: Stenting of the arterial duct is technically feasible. It provides adequate palliation for neonates with pulmonary atresia at least in the short term and it seems to result in balanced, central perfusion of both pulmonary arteries. This preliminary report suggests that this previously untried technique may prove to be a promising and attractive alternative to neonatal aortopulmonary shunt operation.

Dinoprostone

Transoesophageal echocardiography in neonates, infants and children: applicability and diagnostic value in everyday practice of a cardiothoracic unit.

OBJECTIVE: To determine the applicability of and information obtained by transoesophageal echocardiography in neonates, infants, and children in every day practice of a cardiothoracic unit. DESIGN: Four month prospective study. SETTING: Supraregional centre for paediatric cardiothoracic services. PATIENTS AND METHODS: 58 patients aged between four days and 16 years with a wide range of cardiovascular disease underwent transoesophageal echocardiography under sedation or general anaesthetic. One of two paediatric probes (6 or 7 mm diameter), or an adult probe (13 mm in diameter) was used. Whenever possible the investigation was immediately preceded by precordial echocardiography. MAIN OUTCOME MEASURES: Success, failure, technical difficulties, and complications of probe introduction and, when possible, comparison of the information obtained with that obtained from precordial echocardiography. RESULTS: Introduction of the probe was successful in 57 of the 58 patients. The only complication encountered was transient bradycardia during manipulation of the probe in a 2.2 kg baby. The adult (13 mm) probe was successfully used in children as small as 7.0 kg. Below this weight a smaller paediatric probe was required. In 56% of cases transoesophageal ultrasound provided information not obtained from the precordial approach. The technique was of particular value perioperatively and in the immediate postoperative period in neonates and infants and in the presence of valve prostheses and the investigation of mediastinal tumours in older children. CONCLUSIONS: Transoesophageal echocardiography is a valuable additional investigative tool for children of all ages. It is of particular value when acquisition of precordial image is impaired around the time of and after operation and in children with prosthetic valves or mediastinal tumour. Image quality was superior with the adult probe and we recommend the use of this probe unless the patient's weight is below 7 kg, when a paediatric probe allows this technique to be used usefully and safely in babies as small as 2.2 kg.

Adolescent

Continuous wave Doppler echocardiography after surgical repair of coarctation of the aorta.

OBJECTIVE: To find how closely pressure gradients across the aortic arch derived from Doppler echocardiography reflect gradients measured by catheter after surgical repair of coarctation of the aorta. DESIGN: Pressure drop across the aortic arch was measured simultaneously by continuous wave Doppler and double lumen catheter in 20 patients with repaired coarctation of the aorta. RESULTS: The peak pressure drop estimated by Doppler was almost invariably higher than the peak to peak gradient measured by catheter, as might be expected. Wide variation was seen between the Doppler measured pressure drop and instantaneous peak gradient measured by catheter, ranging from +22 to -17 mm Hg. The reasons for these differences are unclear but are probably related to a combination of complex flow dynamics in the aortic arch, difficulty in closely aligning the Doppler beam with flow, and inability to measure flow velocity immediately proximal to the site of the surgical repair with continuous wave Doppler. CONCLUSIONS: Continuous wave Doppler echocardiography may significantly overestimate or underestimate the pressure drop after repair of coarctation and it should be interpreted with caution in individual patients. Catheterisation with angiography remains the reference standard for assessment of surgical repair of the aortic arch.

Adolescent

Chorea after cardiopulmonary bypass: exacerbation by captopril.

Chorea is a rare complication of major cardiac surgery, which has been related to profound hypothermia and circulatory arrest. We describe a case of choreic syndrome in a child which followed normothermic cardiac bypass and only became apparent clinically when the child was treated with captopril.

Captopril

Percutaneous laser valvotomy with balloon dilatation of the pulmonary valve as primary treatment for pulmonary atresia.

A neonate with pulmonary atresia and an intact ventricular septum with a tripartite right ventricle was successfully treated by percutaneous balloon dilatation of the pulmonary valve. This was facilitated by previous laser valvotomy with a hot tip Trimedyne laser wire. There were no major complications. Four weeks later the patient was discharged home on no medication with peripheral oxygen saturations of 70% in air.

Catheterization

Failure of Doppler ultrasound to detect coarctation of the aorta.

Normal velocities of flow in the aortic arch were recorded in a patient presenting with clinical signs of aortic coarctation. Angiography demonstrated complete coarctation with extensive collateral supply to the descending aorta: there was a systolic pressure difference of 40 mm Hg between the ascending and descending segments of the aorta. Despite reports of the value of Doppler ultrasound in the diagnosis of coarctation, the finding of normal velocities of flow within the aortic arch does not necessarily exclude the presence of an obstructive lesion.

Adult

Spontaneous resolution of pulmonary stenosis.

Pulmonary stenosis diagnosed in infancy usually increases in severity with age or, if it is mild, may remain so for many years. We report the case of a child in whom moderately severe pulmonary stenosis in infancy appeared to completely resolve by the age of 8 years.

Female

Limitations of Doppler ultrasound in the diagnosis of neonatal coarctation of the aorta.

Blood flow velocities were recorded using Doppler ultrasound in 40 babies aged between 1 day and 4 weeks who had coarctation of the aorta or interruption of the aortic arch. High velocity jets of 3 m/sec or more in the descending aorta were detected in only 3 patients, two of whom had interruption of the aortic arch. There was very poor agreement between upper and lower limb blood pressure difference and Doppler derived peak pressure drop. Doppler ultrasound may provide useful information on coexisting intracardiac abnormalities, but in the presence of ductal patency is of little value in the diagnosis of coarctation itself.

Aortic Coarctation

Propranolol induced bradycardia in tetralogy of Fallot.

When an 18 month old girl who had tetralogy of Fallot and episodes of severe cyanosis with loss of consciousness was treated with propranolol there was some improvement. But when the dose was increased she had further episodes of near syncope. Holter monitoring showed extreme intermittent bradycardia with pauses of up to 2.6 seconds. The episodes of near syncope and the bradycardia resolved after propranolol was stopped. Apparent failure of propranolol treatment may on rare occasions be related to drug induced bradycardia rather than to continued episodes of severe cyanosis.

Bradycardia

Doppler echocardiographic comparison of haemodynamic results of one- and two-stage anatomic correction of complete transposition.

Eighteen children who had single-stage and 18 who had two-stage anatomic correction of complete transposition between the ages of 1 week and 3 years (mean 6.5 months) were investigated with pulsed and continuous wave Doppler ultrasound. Peak mitral flow velocities showed no significant difference from normal after single-stage correction, but were significantly higher than normal after two-stage correction (P less than 0.05). Peak tricuspid flow velocities were significantly higher than normal in both groups (P less than 0.02 and P less than 0.001). There was no significant difference in pulmonary artery flow velocities between the two groups, which were means (SD) of 214 (84) cm/sec after single-stage and 179 (87) cm/sec after two-stage repair. Peak velocities in the ascending aorta were within normal limits after single-stage correction, but were lower than normal in the two-stage group (P less than 0.02). Mild aortic regurgitation was detected in 22% of single-stage and 55% of two-stage patients (P = 0.043, 2P = 0.085). Both types of repair are associated with higher peak tricuspid flow velocities than normal and have a similar incidence of mild supravalvar pulmonary stenosis. Mitral flow velocities are higher than normal only after two-stage correction. Velocities in the ascending aorta are lower than normal and the incidence of mild aortic regurgitation appears to be increased after two-stage repair, probably due to dilatation of the aortic root following banding of the pulmonary trunk.

Aorta, Thoracic

Doppler ultrasound of normally functioning mechanical mitral and aortic valve prostheses.

Doppler ultrasound flow velocities across clinically normally functioning mitral (Bjork-Shiley, Medtronic Hall, Lillehei-Kaster, Duromedic and Starr-Edwards) and aortic (Bjork-Shiley, Medtronic Hall, Lillehei-Kaster and Duromedic) valve prostheses are described. To enable ease of reference for the echocardiographer and to avoid the need for time-consuming calculations of pressure drops and effective valve orifice areas, peak flow velocities and, where relevant, pressure half times across valves of different types and sizes are tabulated. In the mitral position, there was significant negative correlation between peak velocity and valve size and between pressure half time and valve size only when a large number and a wide range of sizes of a given type of mitral prosthesis was studied. Similarly, there was significant negative correlation between peak velocity and aortic valve size for Bjork-Shiley and Duromedic valves. Regurgitant jets were detected across 18.4% of mitral and 42% of aortic prostheses.

Adolescent

Sinuatrial disease causing persistent fetal bradycardia: intrauterine detection and management.

We report a case of sustained sinus bradycardia, detected at 32 weeks gestation and confirmed by echocardiography, where emergency caesarian section was avoided by demonstration of normal intrauterine cord blood pH and oxygen tension. Delivery at 37 weeks produced a healthy girl who required no resuscitation. The bradycardia persisted and, in the absence of structural heart disease, was attributed to sinuatrial disease. Persistent fetal sinus bradycardia is not necessarily an indication for urgent delivery.

Adult

A quantitative evaluation of aortic regurgitation after anatomic correction of transposition of the great arteries.

Twenty patients who had undergone anatomic correction of transposition of the great arteries were assessed by Doppler echocardiography or cardiac catheterization, or both, to identify the presence of aortic regurgitation. The severity of aortic regurgitation was evaluated by radionuclide angiographic measurement of the stroke volume index a mean of 47.1 months postoperatively. The stroke volume index was defined as the ratio of the stroke counts between the left and right ventricles. A value greater than 1.8 was considered to indicate significant left ventricular volume overload. Eight patients (40%) were shown to have various degrees of aortic regurgitation by Doppler echocardiography or cardiac catheterization, or both. The mean (+/- SD) stroke volume index was 1.03 +/- 0.15 in these patients and 1.01 +/- 0.21 in the 12 patients without aortic regurgitation (p = NS). The stroke volume index was not above the normal range in any patient, indicating that the degree of aortic regurgitation present was trivial. This medium-term study indicates that trivial or mild aortic regurgitation is a frequent finding after anatomic correction of transposition of the great arteries. However, it rarely results in an audible cardiac murmur or significant left ventricular volume overload. Long-term evaluation is required to determine its importance.

Aortic Valve Insufficiency