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Biomedical subjects

B Friedli

Publications and source records attributed to B Friedli.

At least 37 records · Page 2Linked to original sources
PubMed1998

Transcatheter closure of atrial septal defect and patent foramen ovale with ASDOS device (a multi-institutional European trial).

A clinical trial was conducted to assess the feasibility, safety, and efficacy of the atrial septal defect (ASD) occlusion system for transcatheter closure of secundum ASD and patent foramen ovale (PFO) after episodes of cerebral embolism. Occlusion was attempted in 200 patients aged 1 to 74 years (mean 32). The procedure failed in 26 patients (13%); the device was retrieved through a catheter in 20 and through surgery in 6 patients. Procedure-related complications necessitating surgical removal of the device included device embolization in 2, device entrapment within the Chiari network in 1, frame fracture in 1, and perforation of atrial wall in 2. All 6 patients experienced an uneventful postoperative course. An additional 11 patients (6%) underwent surgical removal of the device during follow-up. There were 163 patients (81%) with an implanted ASD occlusion system at follow-up of from 6 to 36 months (mean 17). Thrombus formation around the device was detected by transesophageal echocardiography in 9 patients 1 to 4 weeks after implantation. One of these patients (who had a coagulation factor XII deficiency) suffered a cerebral thromboembolism. Late atrial wall perforation (5, 6, and 8 months after implantation) occurred in 3 adult patients. Infectious endocarditis developed in 2 adult patients (1%). No late device embolization and no atrioventricular valve injury occurred. An asymptomatic device frame fracture was found in 14% and frame deformity in 4% of all patients during the follow-up period of >230 patient-years. Immediately after closure, a moderate/large residual shunt remained in 8% and a small shunt in 29% of patients. After 1 year, a moderate/large shunt was present in 2% and a small one in 26% of patients. During a total follow-up of 49 patient-years, only 1 of 46 patients with PFO had a transient neurologic event after the closure. The study indicates that patients with centrally situated secundum ASD and those with PFO after cerebral embolism can be treated with this system with a high success rate and an acceptable morbidity.

Adolescent↗
PubMed1998

[Short and long term results of pulmonary balloon valvuloplasty in children].

Percutaneous balloon valvuloplasty is an alternative to surgical valvotomy for congenital pulmonary valve stenosis. Between 1985 and 1997, 73 valvuloplasties were performed in 70 patients, age range 1 day to 24.7 years. We reviewed the short- and long-term results in regard to transvalvular gradient and pulmonary insufficiency. The gradient was measured pre- and immediately post-valvuloplasty at catheterization and by Doppler echocardiography, and by echocardiography only at follow-up. Valvuloplasty was successful in 61/70 patients whereas surgical valvotomy was necessary in 9/70 because of a very dysplastic valve. A second valvuloplasty was performed in 3 patients presenting with restenosis. A 60% decrease in the gradient was noted immediately after the procedure, from 78.3 +/- 24.5 to 33.7 +/- 19.7 mm Hg (p < 0.05). A follow-up of more than 2 years (4.2 +/- 2.2 years) was obtained in 35 patients. A further decrease in the gradient was noted, to 20 +/- 12 mm Hg, and the degree of pulmonary insufficiency was mild in all patients except 2 with a moderate leak. The mortality was 0% and only 1 patient had a complication (endocarditis). The short- and long-term results of pulmonary percutaneous balloon valvuloplasty are excellent. It can be considered the therapy of choice. The gradient shows a further decrease during follow-up due to regression of the infundibular muscular stenosis. Failure is attributed to very dysplastic valves and these patients may require, in a second stage, a surgical approach (patch enlargement and/or valvulectomy).

Adolescent↗
PubMed1998

Transcatheter closure of atrial septal defects within the oval fossa: medium-term results in children using the 'ASDOS'-technique.

OBJECTIVES: The purpose of this study was to evaluate the safety and efficacy of the ASDOS-technique (Sulzer-Osypka GmbH, Germany) for transcatheter closure of atrial septal defects within the oval fossa. BACKGROUND: Although several attempts have been made to occlude defects within the oval fossa by transcatheter techniques, none of these has gained general acceptance. METHODS: Patients with a defect in the oval fossa measuring equal to or less than 20 mm diameter, with a residual septal rim of 5 mm or greater, body weight greater than 10 kg, with clinical indications for surgical closure were considered for transcatheter closure. Follow-up investigations were performed at discharge, after 1, 3, 6 and 9 months, as well as after 1 and 2 years. RESULTS: Of 78 patients considered for closure, a device was inserted in 41 patients (53%), with success being achieved in 40 patients (98%). The ages ranged from 1.1 to 15 years (7.8 +/- 1.92 years), the 'stretched' diameter of the defect from 10 to 20 mm (14.7 +/- 2.60 mm), and the diameters of the inserted devices from 25 to 45 mm (33.2 +/- 5.43 mm). Transient impairment of atrioventricular conduction occured in 4 patients. During the follow-up of 23.0 +/- 5.6 months elective surgical closure of a residual shunt was performed 26 months after insertion of the device in one patient. None of the other patients required surgery, hospitalisation or medical treatment, and none is requiring further treatment of the defect within the oval fossa. Fracture of one arm of the device occurred in 4 patients, but the fractured arms are in an unchanged and stable position after a period of at least 19 months. CONCLUSIONS: Our medium-term data show that transcatheter closure in children of defects within the oval fossa can be performed with a high efficacy and safety using the ASDOS-device.

Adolescent↗
PubMed1997

Multiple-leaflet mitral valve as a rare cause of congenital mitral insufficiency.

A rare case of congenital mitral insufficiency characterized by six well-demarcated leaflets of mitral valve and annular dilatation is reported. At operation, the mitral valve was successfully repaired by resection of the posterior median leaflet with subsequent annular plication, closure of unusual valvular tissue divisions, and ring annuloplasty.

Child↗
PubMed1997

Successful weaning from cardiopulmonary bypass after cardiac surgery using inhaled nitric oxide.

Two cases of very difficult weaning from cardiopulmonary bypass after cardiac surgery in children with pulmonary hypertension and ventricular dysfunction are reported. Children fail to respond to conventional therapy combining nitrovasodilators and inotropic support and react successfully to combined inhaled nitric oxide (NO) and epinephrine or left atrial infused norepinephrine. Postoperative NO inhalation must be prolonged and no toxicity appears. Pulmonary endothelial function recovers only after several days.

Administration, Inhalation↗
PubMed1996

Inhaled nitric oxide to test the vasodilator capacity of the pulmonary vascular bed in children with long-standing pulmonary hypertension and congenital heart disease.

Nitric oxide-induced vasodilator capacity greatly varies among children with pulmonary hypertension and elevated vascular resistance. The decline of this selective response seems to parallel the progression of established vascular disease and thus may be helpful for the selection of patients for operation.

Administration, Inhalation↗
PubMed1996

Haemodynamic and renal effects of dopexamine after cardiac surgery in children.

Dopexamine hydrochloride, a synthetic dopamine analog with predominantly beta and delta agonist properties, has been shown to improve cardiac performance and renal function in adults with heart failure. This study was designed to investigate the haemodynamic and renal effects of dopexamine in children after cardiac surgery. Seven children were selected in whom a need for postoperative vasodilation after cardiac surgery was anticipated. Haemodynamics and renal function were determined under baseline conditions and during a continuous infusion of dopexamine at 2 and 6 micrograms.kg-1.min-1 for 90 minutes, the sequence being randomized for the initial dose. Cardiac output was measured by thermodilution and glomerular filtration rate (GFR) and renal plasma flow (RPF) by the clearances of inulin and para-aminohippurate respectively. Dopexamine induced a dose-related increase in cardiac index (CI) expressed as mean (SD) from 3.5 (0.7) to 3.9 (0.76) and 4.5 (0.8) l.min.-1m-2 (both P < 0.05), and in heart rate (HR) from 107 (17) to 122 (17) and 136 (17) beats.min-1 (P < 0.05). Stroke volume index (SVI) and mean systemic pressure were unchanged, but pulmonary wedge pressure decreased from 14 (3) to 11 (4) and 12 (3) mmHg (both P < 0.05). Systemic vascular resistances (SVR) decreased from 24 (7) to 20 (5) mmHg.l-1.min-1.m-2 (P < 0.05), with dopexamine 6 micrograms.kg-1.min-1. Renal blood flow (RBF) increased from 319 (113) to 441 (230) and 410 (138) ml.min-1.m-2 (both P < 0.05), GFR from 115 (32) to 142 (34) and 146 (29) ml.min-1.1.73m-2 (both P < 0.05), urine output and fractional excretion of sodium respectively from 3.12 (2) to 7.16 (8) and 7.21 (6) ml.kg-1 (both P < 0.05) and from 2.24 (1) to 4.25 (3.4) (P < 0.05) and 3.15 (3.1)% (n.s.). The fraction of CI delivered to the kidneys, the fraction of RBF filtered in the kidneys, plasma renin activity and aldosterone levels remained unchanged. In children after cardiac surgery, dopexamine increases CI at the expense of a concomitant increase in heart rate and demonstrates few selective vascular systemic or intrinsic renal actions.

Adolescent↗
PubMed1996

[Arrhythmia after surgery for congenital cardiopathies. What studies? What treatment?].

Cardiac surgery has greatly improved the outlook for patients with heart defects, giving them a much longer lifespan; it has also created specific problems and morbidity, amongst which arrhythmias are most prominent. The incidence of rhythm disturbances increases with age and duration of follow-up. To a large extent, the type of surgery determines the type of arrhythmias: conduction disturbances and ventricular arrhythmias are common after ventricular surgery (e.g. tetralogy of Fallot) whereas sinus node dysfunction, with its bradycardias and tachycardias, is prominent after atrial surgery (e.g. Mustard or Senning operations). Various types of investigations, both non invasive (Holter, exercise testing, signal averaging) and invasive electrophysiology) are available. The usefulness of these different techniques for each type of rhythm disturbance is discussed. Regarding treatment, abstention is the best approach in many cases. Others however require treatment to suppress symptoms and, sometimes, to try and prevent sudden death. The indication for various antiarrhythmic medications and also for pacemaker implantation are discussed. Radio frequency ablation appears to hold some promise for the future.

Anti-Arrhythmia Agents↗
PubMed1995

Successful term pregnancy after Mustard operation for transposition of the great arteries.

Transposition of the great arteries is a complex cardiac malformation with poor prognosis without surgical correction. Since the introduction of surgical procedures such as the intra-auricular reorientation of the venous return (Mustard procedure), an increasing number of patients may reach adulthood and experience pregnancy. Because long-term complications after the Mustard operation include systemic heart failure, arrhythmias, venous return stenosis and pulmonary edema, hemodynamic changes during pregnancy and delivery may potentially engender life-threatening complications in these patients. We report the case of a 24-year-old primigravida who underwent a Mustard procedure at the age of 2 years for transposition of the great vessels, and who carried out a full-term pregnancy. The pregnancy was uneventful until the 34th week, when the woman developed signs of moderate right ventricular failure and frequent episodes of accelerated junctional rhythm. Digitalisation improved symptoms and elicited return to normal sinus rhythm. The patient delivered at term by elective cesarean section, under close hemodynamic monitoring.

Adult↗
PubMed1995

Continuous low dose inhaled nitric oxide for treatment of severe pulmonary hypertension after cardiac surgery in paediatric patients.

OBJECTIVE: To assess the effect of inhaled nitric oxide (NO) on severe postoperative pulmonary hypertension in children after surgical repair of a congenital heart defect. DESIGN: A pilot study of NO administration to 7 consecutive children who required adrenergic support and in whom postoperative mean pulmonary artery pressure was more than two thirds of mean systemic pressure and persisted despite alkalotic hyperventilation. SETTING: Routine care after cardiac surgery for congenital heart disease in a multidisciplinary paediatric intensive care unit. METHODS: Continuous inhalation of NO, initially at 15 ppm. Therefore, daily attempts at complete weaning or at reducing NO to the lowest effective dose. RESULTS: In 6 of the 7 children NO inhalation selectively decreased mean (SD) pulmonary artery pressure from 51 (12) to 31 (9) mm Hg (P < 0.05) while mean systemic arterial pressure was unchanged (68 (10) v 71 (7) mm Hg) (NS) and the arteriovenous difference in oxygen content decreased from 6.7 (0.9) to 4.8 (0.8) vol% (P < 0.05). Concomitantly PaO2 increased from 158 (98) to 231 (79) mm Hg) (P < 0.05). The seventh child showed no response to NO up to 80 ppm, could not be weaned from cardiopulmonary bypass, and died in the operating room. In responders, attempts at early weaning from NO inhalation always failed and NO at concentrations of less than 10 ppm was continuously administered for a median of 9.5 days (range 4 to 16 days) until complete weaning was possible from a mean dose of 3.9 (2.9) ppm. Methaemoglobinaemia remained below 2% and nitrogen dioxide concentrations usually ranged from 0.1 to 0.2 ppm. One child later died and five were discharged. A few months after surgery Doppler echocardiography (and catheterisation in one) showed evidence of regression of pulmonary hypertension in all 5. CONCLUSIONS: Inhalation of NO reduced pulmonary artery pressure in children with severe pulmonary hypertension after cardiac surgery and this effect was maintained over several days at concentrations carrying little risk of toxicity.

Administration, Inhalation↗
PubMed1994

Ventricular late potentials and spontaneous ventricular arrhythmias after surgical repair of tetralogy of Fallot: do they have prognostic value?

OBJECTIVE: To determine the prognostic significance of ventricular late potentials and spontaneous ventricular arrhythmias detected early after surgical repair of tetralogy of Fallot. DESIGN: Prospective observational. SETTING: Cardiology department of a teaching hospital. METHODS: Between June 1984 and June 1991, 104 children (63 boys, 41 girls) were studied by signal averaging and 24 hour ambulatory monitoring after surgical repair of tetralogy of Fallot. Mean (SD) age at operation was 6 (3) years, mean interval between operation and evaluation was 8 (25) months, and the follow up after evaluation was one to 88 (mean 30) months. RESULTS: Ventricular late potentials were detected in 24/104 patients (23%) and spontaneous ventricular arrhythmias in 39/96 patients (38%); usually (in 81%) these were unifocal and rare. Patients with ventricular late potentials were older at operation than patients without late potentials (9 (3) v 6 (3) years, P = 0.002). No correlation was found between the presence of ventricular late potentials and the presence or complexity of spontaneous ventricular arrhythmias early after operation. During the mean follow up of 2.5 years no case of sudden death or sustained ventricular tachycardia was found. CONCLUSION: Short-term prognosis after surgical repair of tetralogy of Fallot is good; ventricular late potentials and spontaneous ventricular arrhythmias are often detected shortly after operation, but in the medium term follow up they do not predict sudden death or serious ventricular arrhythmias.

Adolescent↗
PubMed1994

Use of Gianturco Z stents in the treatment of vascular compression of the tracheobronchial tree in childhood. A feasible solution when surgery fails.

Severe tracheomalacia secondary to extrinsic vascular compression following a switch operation for transposition is reported. Two attempts at surgical correction failed but successful treatment has been achieved by implantation of two endobronchial Gianturco Z stents. Nonabsorbable stenting in children should be used only in severe obstruction as a last resource, but this technique proved to be feasible in a child weighing 6.2 kg.

Bronchial Diseases↗
PubMed1993

[Arrhythmias in the adolescent and adult with a congenital heart defect].

Rhythm disturbances may be observed in the natural history of congenital heart defects, as well as after open heart surgery. About 40-50% of adults with congenital heart defects will experience some type of arrhythmia. In the growing population of postoperative patients, the type of rhythm disturbance depends on the type of heart surgery: after operation at ventricular level, conduction disturbances and ventricular arrhythmias are quite common. After surgery at atrial level (e.g. closure of ASD, but much more after atrial correction of transposition), sick sinus syndrome and supraventricular arrhythmias are chiefly observed. Conduction disturbances may be subdivided into the very common intraventricular conduction defects (right bundle branch block, sometimes with left anterior hemiblock) and complete A-V block. Complete heart block has become less frequent in recent years since surgeons have learnt to avoid the bundle of His during VSD closure. All patients with postoperative complete heart block need a permanent pacemaker. Ventricular arrhythmias after ventricular surgery are commonly found if Holter recordings are done, particularly after correction of tetralogy. They are often asymptomatic but may be a cause of late sudden death (1-3% of patients operated on for tetralogy). Antiarrhythmic treatment is indicated if symptoms are present, or in selected asymptomatic patients with a poor hemodynamic result (severe residual pulmonary stenosis or ventricular dysfunction). Sinus node dysfunction and sick sinus syndrome are common after atrial repair of transposition (Mustard or Senning operation). The manifestations are either sinus bradycardia and sinus arrest with long pauses, or atrial reentry tachycardia (Flutter); these may combine, so that antiarrhythmic medication must be associated with permanent pacemaker implantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

[Childhood treatment of paroxysmal supraventricular tachycardia using i.v. adenosine].

Paroxysmal supraventricular tachycardia is the most frequent significant arrhythmia in the pediatric age group, especially in the first year of life. In neonates and infants there are important limitations for the commonly used drugs such as verapamil and digitalis. In an open Swiss multicentre study we treated 19 children with a total of 29 episodes of tachycardia by means of adenosine i.v. as the drug of first choice. 76% of all the tachycardias were converted, whereas the success rate was 87% if only tachycardias with atrioventricular reentry were considered. The important advantage of adenosine lies in its very short half-life of about 15 seconds, which means that the rare relevant, and the more common mild, side effects are quite limited in duration. A major disadvantage are recurrences in about one third of cases. We conclude that adenosine is an efficient and safe treatment for paroxysmal supraventricular tachycardia in the whole pediatric age group including neonates and infants.

Adenosine↗
PubMed1993

In vivo persistence of expanded clones specific for bacterial antigens within the human T cell receptor alpha/beta CD4-8- subset.

We analyzed the T cell receptor (TCR) rearrangements of 100 TCR-alpha/beta CD4-CD8- (double negative [DN]) T cell clones from normal individuals. We found that in four out of six donors this subset contains expanded clones that often account for 0.5% and, in one individual, even 7% of all peripheral blood lymphocytes. By combining limiting dilution analysis and N region oligotyping of polymerase chain reaction amplified TCR cDNA, we could measure the clonal size and show that two of these expanded clones remain stable in size for up to 4 yr in peripheral blood. The expanded clones analyzed ex vivo are not cycling and CD45 RAhi ROlo, but express high levels of alpha 4/beta 1 integrins, suggesting that they may have reverted to resting cells after activation. One of these expanded DN clones proliferates in vitro in response to Escherichia coli presented by monocytes cultured in GM-CSF plus IL-4 and kills CD1a+ Molt-4 cells. In contrast to what was found in the alpha/beta DN subset, alpha/beta CD4+ T cell clones specific for a tetanus toxin epitope showed a very small clonal size (< 1 in 10(7)) and could not be reisolated after 2 yr. Taken together, these results indicate that large clonal size and persistence are distinctive features of alpha/beta DN cells specific for bacterial antigens. These cells may use antigen-presenting cells, restriction molecules, and selection routes different from those used by antigen-specific CD4+ T cells.

Amino Acid Sequence↗
PubMed1993

[Closure of patent ductus arteriosus using interventional catheterization].

Percutaneous closure of patent ductus arteriosus can be performed with the Rashkind technique. This procedure has been performed in 16 patients in Geneva since 1989. The age of the patients varied from 2 to 44 years (4 boys, 7 girls, and 5 women). Pulmonary hypertension was present in only 1 child. A 12 mm Rashkind umbrella was used in 11 patients with ductus of < or = 4 mm inner diameter, while a 17 mm umbrella was used in 5 cases for larger ducts. Ductus closure was carried out through a transvenous femoral approach in 15 cases, while in 1 patient a transarterial approach was employed because of impossibility of passing the ductus from the pulmonary artery. There was neither mortality nor morbidity in this series. The aortography performed just after device placement showed total ductus occlusion in 8 patients and partial closure in 8 others. The follow-up by color Doppler showed disappearance of the residual shunt in 4 of these 8 patients. Prophylaxis of bacterial endocarditis is therefore no longer necessary in 13 patients with complete ductus closure. Our experience with this technique confirms its efficacy and the possibility it offers of avoiding thoracotomy in the vast majority of patients with a patent ductus arteriosus. Further miniaturization of the device and delivery system should make it applicable in the neonatal period.

Adolescent↗