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Biomedical subjects

D Sidi

Publications and source records attributed to D Sidi.

At least 127 records · Page 7Linked to original sources
PubMed1997

Aconitase and mitochondrial iron-sulphur protein deficiency in Friedreich ataxia.

Friedreich ataxia (FRDA) is a common autosomal recessive degenerative disease (1/50,000 live births) characterized by a progressive-gait and limb ataxia with lack of tendon reflexes in the legs, dysarthria and pyramidal weakness of the inferior limbs. Hypertrophic cardiomyopathy is observed in most FRDA patients. The gene associated with the disease has been mapped to chromosome 9q13 (ref. 3) and encodes a 210-amino-acid protein, frataxin. FRDA is caused primarily by a GAA repeat expansion within the first intron of the frataxin gene, which accounts for 98% of mutant alleles. The function of the protein is unknown, but an increased iron content has been reported in hearts of FRDA patients and in mitochondria of yeast strains carrying a deleted frataxin gene counterpart (YFH1), suggesting that frataxin plays a major role in regulating mitochondrial iron transport. Here, we report a deficient activity of the iron-sulphur (Fe-S) cluster-containing subunits of mitochondrial respiratory complexes I, II and III in the endomyocardial biopsy of two unrelated FRDA patients. Aconitase, an iron-sulphur protein involved in iron homeostasis, was found to be deficient as well. Moreover, disruption of the YFH1 gene resulted in multiple Fe-S-dependent enzyme deficiencies in yeast. The deficiency of Fe-S-dependent enzyme activities in both FRDA patients and yeast should be related to mitochondrial iron accumulation, especially as Fe-S proteins are remarkably sensitive to free radicals. Mutated frataxin triggers aconitase and mitochondrial Fe-S respiratory enzyme deficiency in FRDA, which should therefore be regarded as a mitochondrial disorder.

Aconitate Hydratase↗
PubMed1997

[Congenital coronary-cardiac fistula in children. Effects of surgical occlusion and percutaneous embolization].

Twenty-four children aged 2 months to 8 years (average: 3 years) with congenital coronary artery fistulae were studied. In 20 cases, the fistula presented with a continuous murmur: in 4 cases, pulmonary flow was increased to such an extent that it led to cardiac failure. Echocardiography and coronary angiography showed that the fistula originated from the left coronary artery or one of its branches in 13 cases and from the right coronary artery in 11 cases. All but one fistula, which drained into the left atrial appendage, drained into the right heart chambers (ventricle: 14 cases; atrium: 9 cases). Spontaneous regression after 9 years was observed in 1 case. The other children were treated: by surgery in 20 cases (1 external ligature and 19 open heart occlusions) with 2 residual shunts (including the case ligated) which had to be reoperated. Three children underwent percutaneous embolisation resulting in 1 failure and 2 successes. After an average follow-up of 6.5 years (5 months to 15.5 years), all patients were alive and doing well with normal resting and exercise ECGs, normal Thallium scintigraphy (5 cases) and normal left ventricular function on echocardiography. Selective control coronary angiography (14 cases) showed a reduction in fistula diameter from 10 +/- 3.7 to 4.5 +/- 1.2 mm (p < 0.0001). The authors conclude that all congenital coronary fistulae should be occluded, by percutaneous embolisation when the anatomical features are favourable. The other cases require surgical occlusion, the long-term results of which are very good.

Cardiac Surgical Procedures↗
PubMed1997

[Double discordances with ventricular septal defect and pulmonary obstruction. A study of 72 cases].

Seventy-two patients with corrected transposition of the great arteries with ventricular septal defect and pulmonary obstruction were studied. Four deaths occurred in the neonatal period and two were lost to follow-up. The remaining 66 were divided into three groups: 1) Eight patients were not operated on because the lesions were well compensated; they are all alive and doing well eight years later. 2) Thirty-eight patients were treated with palliative surgery: one or more systemico-pulmonary shunts (33 cases), total cavo-pulmonary connection (1 case) and partial cavo-pulmonary connection complementary to a shunt (4 cases). There were 3 deaths and 17 patients were lost to follow-up. However, the 18 survivors are all well seven years later. 3) The other 20 patients underwent surgery for severe hypoxia, after previous shunt in 18 cases. A conventional surgical protocol was respected in 17 cases (closure of ventricular septal defect with pulmonary disobstruction by a direct pulmonary plasty or by ventriculo-pulmonary conduit). There were 4 deaths, 2 tricuspid valve replacements, 5 complete atrioventricular blocks requiring permanent pacing, 5 lost to follow-up and 8 good results after 4 years follow-up. In the last 3 cases, "anatomical" correction was attempted by tunnelling of the left ventricle to the aorta, conduit from the right ventricule to the pulmonary artery and intra-atrial Mustard procedure: these 3 children are doing well after 1 year though one of them required permanent pacing. Therefore, there is no place for elective surgery in this malformation: when necessary, the best option is to remain palliative as long as possible: when correction is required, an anatomical correction is the best procedure.

Cardiac Surgical Procedures↗
PubMed1997

[Non-surgical ventricular training before arterial switch. Focus on an animal model in lambs].

One of the conditions for successful anatomical correction of transposition of the great arteries (arterial switch) or of double discordance (double switch) is the ability of the subpulmonary left ventricle to adapt to the systemic circulation when restored to its subaortic position. A balloon catheter designed for training the subpulmonary ventricle by progressive occlusion of the main pulmonary artery (NuMed) was implanted in six lambs aged 45 days and inflated progressively to obtain the maximum tolerated right ventricular pressure. Six controls were instrumented without balloon inflation. The experiment lasted 5 days. Progressive inflation of the balloon to a right ventricular pressure > 70% of the systemic (carotid) pressure led to bradycardia with venous desaturation and acidosis which regressed when the balloon was deflated. In one animal, progressive adjustment enabled a right ventricular pressure of 75% of the systemic pressure to be obtained throughout the last day of the study. No significant right ventricular hypertrophy was obtained. The value of this technique is in assessing the afterload reserve of the tested ventricle before surgical banding of the pulmonary artery, the first step to anatomical correction for restoration of concordance of double discordance or of transposition of the great arteries previously treated by a Senning or Mustard procedure.

Animals↗
PubMed1997

[Aortic-ventricular tunnel with right coronary artery atresia].

An aortico-left ventricular tunnel was diagnosed at echocardiography in a 6 week old baby after fortuitous detection of a systolic and diastolic murmur. Its association with atresia of the right coronary ostium, suspected at echocardiogoraphy, was confirmed at surgery which included occlusion of the tunnel orifices, aortic commissurotomy and reimplantation of the right coronary artery. The short-term postoperative result is excellent. This is an exceptional malformation, the clinical diagnosis of which is relatively easy. Its relationship with the right coronary artery conforms to an embryological logic and must be investigated thoroughly before surgery to avoid compromising myocardial revascularisation.

Aorta, Thoracic↗
PubMed1997

[Marfan's syndrome. Cardiovascular manifestations and therapeutic indications].

Marfan's syndrome is a disease of collagen microfibrils, the essential composition of which, fibrillin, is defective. The coding gene of this large protein has been localised on chromosome 15 and partially cloned. Its mutation is transmitted in the autosomal dominant mode. It is common, affects many organs, especially those rich in collagen. They include the skeleton, the eye and cardiovascular system. The prognosis of these patients depends on the degree of cardiovascular involvement; the aorta is the principal site of the lesions, particularly the aortic root which tends to develop aneurysmal dilatation, then dissection, the main cause of premature death of these patients. Mitral valve prolapse giving rise to mitral regurgitation may also be observed. Much progress has been made is recent years in the management of Marfan's syndrome, especially in ultrasound follow-up of the aortic root and the definition of risk factors for dissection. In parallel, advances have been made in the treatment, both medical with the use of betablockers to try to slow progression to aneurysm, and surgical, in replacement of the aorta and aortic valve in time and under optimal conditions. Life expectancy is thereby significantly increased. Similar progress has been made to allow these patients to have a pregnancy, classically thought to carry a high risk of maternal death.

Adrenergic beta-Antagonists↗
PubMed1996

[Purulent pericarditis in children: a 15 year-experience].

BACKGROUND: Purulent pericarditis is rare in developed countries, but its prognosis is regarded as serious. Early diagnosis and appropriate treatment should prevent complications. PATIENTS: Among the 119 pericarditis without congenital cardiopathy admitted in our pediatric cardiology unit between 1979 and 1994, 19 were purulent. The mean age of these 13 boys and six girls was 3 years (range: 3 months to 10 years). Symptoms always pointed to a chest disease whether pericarditis occurred first (n = 13) or it complicated evolution of a known infectious process (n = 6). Tamponnade was present in seven infants upon admission and required urgent pericardiocentesis or drainage. An extrapericardial infectious site was found in 11 cases: six pulmonary infections, three osteomyelitis, one cellulitis and one sinusitis. An organism was isolated in 17 cases, 14 times in the pericardial fluid, eight times on blood culture. The identified bacteria were: Staphylococcus aureus (n = 6), Haemophilus influenzae (n = 4), Streptococcus A (n = 3), Streptococcus pneumoniae (n = 3), Meningococcus (n = 1). Treatment consisted of intra-venous antibiotics associated 15 times to surgical drainage of the pericardium. One infant had no pericardiocentesis and no drainage because he presented late with constrictive pericarditis and needed pericardectomy. All infants healed but four developed contrictive pericarditis and required pericardectomy; none of these four patients had early drainage (two had no drainage at all). Pericardectomy, carried out between 2 and 6 months after the beginning of pericarditis with adiastolic signs and pericardial thickening, permitted healing in all cases and disappearance of all cardiac symptoms. CONCLUSIONS: Early diagnosis and treatment of purulent pericarditis, especially early pericardial drainage, are the best ways of avoiding constriction.

Child↗
PubMed1996

The multi-track angiography catheter: a new tool for complex catheterisation in congenital heart disease.

OBJECTIVE: To develop a simple and versatile catheter system for complex cardiac catheterisation because angiography and pressure measurements during diagnostic and interventional cardiac catheterisation are often unsatisfactory. METHODS: The Multi-Track Angio catheter system is a single lumen side-hole catheter with a short distal extension containing a lumen for a standard guidewire. The catheter is introduced over a previously placed guidewire running through this distal extension. It can then be manipulated within the heart by sliding along the guidewire. The tip of the catheter is always stabilised by the guidewire. This stability enhances angiography and pressure recordings. RESULTS: The Multi-Track Angio catheter system was used in 84 patients (age 1 day-20 years). Thirty one procedures were diagnostic and 53 interventional. The decision to use the Multi-Track Angio catheter was based on three criteria: firstly, unsatisfactory angiography obtained with conventional equipment; secondly, difficult catheter course requiring use of a guidewire; and thirdly, requirement for angiography and pressure recordings during interventional procedures. No complications were encountered. High quality angiography could be performed in all cases without catheter recoil. CONCLUSIONS: The Multi-Track Angio catheter system allows for high quality angiography and pressure recordings during diagnostic and interventional cardiac catheterisation. The advantage of the system is that both angiography and pressure recordings can be performed repeatedly from stable catheter positions using a previously placed guidewire. This reduces the need for guidewire manipulations or catheter exchanges and decreases procedure time and the risk of complications.

Adolescent↗
PubMed1996

Long-term fate of the coronary arteries after the arterial switch operation in newborns with transposition of the great arteries.

OBJECTIVE: Concern continues to be expressed about the long-term impact of coronary artery translocation after the arterial switch operation for transposition of the great arteries. This study was conducted to determine the prevalence of obstructions of the translocated coronary arteries by the use of selective coronary artery angiography. METHODS AND RESULTS: 64 children (mean age 7.6 (SD) 1.5 years) who had survived an arterial switch operation underwent evaluation. They had been operated on by one surgeon and they were followed up by a single hospital. Selective coronary artery angiography was possible in 58 patients. Five patients showed occlusion or stenosis of a coronary artery: one occlusion and two stenoses of the left coronary trunk, two occlusions of the circumflex artery. The prevalence of late coronary artery complications was 7.8 (SD) 6.6% (95% CI 1.2 to -14.4%). The three patients with occlusion of one coronary artery had perioperative ischaemic complications, with associated electrocardiogram evidence of ischaemia and left ventricular dysfunction with mitral valve insufficiency. Both patients with stenosis of the left main coronary artery trunk did not have any evidence of an anomaly before catheterisation. CONCLUSIONS: The prevalence of the late coronary artery complications after an arterial switch operation was low in this series. This accords with the view that the arterial switch operation remains the preferred treatment for such patients. Screening for late coronary artery patency should be done by using selective coronary artery angiography, because even patients who remain symptom free can have coronary artery anomalies.

Coronary Angiography↗
PubMed1996

Pulmonary balloon valvuloplasty in the palliation of complex cyanotic congenital heart disease.

OBJECTIVE: To assess the value of pulmonary balloon valvuloplasty in the interim palliation of complex congenital heart disease and pulmonary stenosis in children, who often require numerous palliative operations before definitive surgical repair. METHODS: Evaluation of pulmonary balloon valvuloplasty procedures performed over a five year period in 18 patients (age 8 days--29 years; mean 5.5 years) with complex cyanotic congenital heart disease. RESULTS: After pulmonary balloon valvuloplasty oxygen saturation increased from a mean (SD) of 69 (7.5)% to 83 (7.0)% (P < 0.001). Mean pulmonary artery pressure increased from a mean (SD) of 11.3 (3.8) mm Hg to 15.7 (3.9) mm Hg (P < 0.001). Transient complete atrioventricular block occurred in one patient. No other complications were encountered. In 5 patients (28%) there was an inadequate improvement in cyanosis compared with pre-procedure values (72 (4.7)% v 66 (8.1)%). Reasons for failure were increasing infundibular stenosis in three and inadequate mixing in one child. In 13 patients (72%) pulmonary balloon valvuloplasty gave adequate interim palliation over a mean follow up of 1.1 (1.3) years. Oxygen saturation was 81 (5.6)% at last follow up compared with 70 (7.3)% before pulmonary balloon valvuloplasty (P < 0.001). CONCLUSION: Pulmonary balloon valvuloplasty is a safe and effective technique in the palliation of patients with complex cyanotic congenital heart disease associated with pulmonary valve stenosis.

Adolescent↗
PubMed1996

[Cardiac MIBG imaging: a new marker for myocardial function in children?].

MIBG cardiac imaging is a non-invasive procedure of studying neuronal recapture of noradrenaline. In adult cardiomyopathy, abnormal results are observed earlier than the increase in circulating catecholamines and constitute a reliable prognostic indicator of the disease. The authors assessed this technique in children with severe cardiac dysfunction in whom the evaluation of ventricular pump function was of primordial importance for the therapeutic decision. Twenty-eight patients aged 3 months to 20 years (average 6.4 +/- 5.8 years) were included in the study. Twenty had hypokinetic dilated cardiomyopathies: with respect to the normal values in adults MIGBG uptake was reduced in all cases. This alteration was correlated with the severity of myocardial dysfunction assessed by echocardiography but is was without doubt the expression of another type of physiopathological process. No relationship was observed with the aetiology of the cardiomyopathy. Eight children had a single ventricle treated by cavopulmonary bypass in 7 cases and by pulmonary artery banding in the other case: MIBG imaging did not allow assessment of myocardial function in these patients probably because the cavopulmonary bypass denervated the heart and thereby changed MIBG uptake independently of the cardiac function. These preliminary results are encouraging and should lead to the adoption of MIBG imaging as one of the key investigations in the functional evaluation of childhood cardiomyopathy and perhaps as an important parameter in the decision of transplantation in this indication.

3-Iodobenzylguanidine↗
PubMed1996

[Treatment and prognosis of tachyarrhythmia after atrial surgical repair of transposition of great vessels].

The Mustard and Senning procedures may be complicated by atrial tachyarrhythmias. In order to determine their prognosis, the authors undertook a review of the 288 patients operated and followed up in their department. Thirty-six (12.5%) had documented atrial tachycardias. In 13 cases, Holter monitoring showed bursts of atrial tachycardia. In the other 23 cases, the tachycardia was sustained and often caused severe symptoms (syncope). Reduction of the sustained forms was obtained by rapid atrial pacing, cardioversion or amiodarone therapy. After restoration of sinus rhythm, several therapeutic protocols were used, often in the same patient: abstention, leading to 5 recurrences in 6 cases; treatment with betablockers in 12 patients with well tolerated or exercise-induced atrial tachycardia with 11 successes; amiodarone, with 4 relapses out of 5 when the dosage was less than 200 mg/m2/day and 13 successes out of 18 when the dosage was 200-250 mg/m2/day. During a follow-up of 1 to 19 years, 6 severe complications (neurological sequellae, cardiac failure), and 6 deaths, were observed. All these patients were poorly controlled and continued to be have tachyarrhythmias. The authors conclude that tachyarrhythmias are neither rare nor always symptomatic, so justifying their systematic investigation. They should be reduced by oral amiodarone or rapid atrial pacing depending on the clinical urgency, never by intravenous antiarrhythmics which can be dangerous. The poor prognosis associated with tachyarrhythmias makes their control essential either with betablockers or good doses of amiodarone, eventually covered by permanent cardiac pacing.

Adolescent↗
PubMed1995

Upper limb malformations in DiGeorge syndrome.

We report on upper limb anomalies in two children with a complete DiGeorge sequence: conotruncal defects, hypocalcemia, thymic aplasia, and facial anomalies. One child had preaxial polydactyly, and the other had club hands with hypoplastic first metacarpal. In both patients, molecular analysis documented a 22q11 deletion. To our knowledge, limb anomalies have rarely been reported in DiGeorge syndrome, and they illustrate the variable clinical expression of chromosome 22q11 deletions.

Chromosome Deletion↗
PubMed1995

Mitral dilatation with the Multi-Track system: an alternative approach.

We developed a simple and versatile new technique (Multi-Track) for percutaneous mitral valvotomy using two two separate balloon catheters positioned on a single guidewire. The first catheter, with only a distal guidewire lumen and a proximal balloon, is introduced over the guidewire into the vein and then advanced into the mitral valve orifice. Subsequently, a normal balloon catheter running on the same guidewire is inserted and lined up with the first catheter so the two are positioned side by side. The balloons are then inflated simultaneously. The technique was applied in 12 patients between 10 and 44 years of age (mean, 27.1) and weighing 24-80 kg (mean, 50.3). Valve area increased from 0.66 cm2 (range, 0.3-0.9 cm2) to 1.97 cm2 (range, 1.3-3.1 cm2) and mean left atrial pressure dropped from 31 mmHg (range, 18-52 mmHg) to 12 mmHg (range, 5-22 mmHg). Mitral dilatation with the Multi-Track system gives results comparable to those with previously described techniques and uses simpler and less costly catheters.

Adolescent↗
PubMed1995

Balloon valvotomy for critical stenosis or atresia of pulmonary valve in newborns.

OBJECTIVES: Percutaneous balloon valvotomy was studied retrospectively in newborns with critical pulmonary valve stenosis or atresia to assess its potential role as an alternative therapy to operation. BACKGROUND: Severe right ventricular outflow tract obstructions are life-threatening conditions requiring prostaglandin infusion immediately after birth and then relief of the valvular obstruction. To avoid surgical hazards at this age, it would be useful to extend to newborns the balloon valvotomy so effective in older patients. METHODS: Ninety-seven newborns (82 with critical pulmonary valve stenosis, 15 with atresia) underwent balloon valvotomy, provided that they had a well developed right ventricle, including an infundibulum close to the pulmonary artery. In patients with atresia, the outflow tract membrane had to be perforated with a wire needle or a radiofrequency probe. RESULTS: Balloon valvotomy could be performed in 81 patients and was effective in 77. It caused 3 fatal and 16 nonfatal complications. Ten patients with persistent poor right ventricular compliance despite an effective valvotomy required a surgical shunt. Among the 81 patients in whom the procedure could be performed, right ventricular surgery was avoided in 5 (55%) of the 9 patients with atresia (95% confidence interval [CI] 28% to 80%) and 55 (76%) of the 72 patients with stenosis (95% CI 66% to 86%) at the end of the follow-up period (9.7 years). CONCLUSIONS: Balloon pulmonary valvotomy is not always feasible in newborns, but it is relatively safe and effective and should be considered a valid alternative to operation.

Catheterization↗