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Biomedical subjects

P Bonhoeffer

Publications and source records attributed to P Bonhoeffer.

At least 55 records · Page 3Linked to original sources
PubMed1999

[Treatment of obstruction of prosthetic conduct by percutaneous implantation of stents].

Prosthetic conduits, with or without biological valves, are often inserted in surgical procedures to correct or palliate cardiac malformations. The principal problem is degeneration which causes variable degrees of obstruction requiring reoperation for their replacement. The aims of this study were to assess the feasibility, safety and efficacy of a non-surgical method of treating these obstructive prostheses by dilatation-implantation of a metallic vascular endoprosthesis (stenting). Thirteen patients were treated (age range 7.7 to 36 years; mean: 15 years). Eight had pulmonary atresia with a ventricular septal defect corrected by a valved conduit from the right ventricle to the pulmonary artery which became obstructive nearly 10 years later: the implantation of the stent reduced the transconduit pressure gradient in all cases except one who had not undergone closure of the septal defect in which the cyanosis was improved. There are two cases of obstruction of a modified Blalock anastomosis in which the stent revascularised the shunt with improvement in cyanosis. In the final 3 cases, the whole Fontan procedure was compromised by obstruction of a conduit incorporated in the system, and which dilatation with stenting considerably improved. The efficacy of the procedure was constant with no complications other than rupture of the balloon in 3 cases. The good results were maintained for an average of 7.3 months (range 1 to 25 months), but it was necessary to redilate one restenosed stent after 8 months. Dilatation followed by stenting in obstructive cardiovascular prostheses is a simple, safe and effective alternative to surgical reoperation.

Adolescent↗
PubMed1999

Percutaneous balloon mitral valvotomy: initial experience in Nairobi using a new multi-track catheter system.

OBJECTIVE: To determine efficacy and safety of the new multi-track catheter system for percutaneous baloon mitral valvotomy. DESIGN: Open, non-randomised intervention. SETTING: Cardiac catheterisation Laboratories of Mater Misericordiae Hospital (1997) and Kenyatta National Hospital, Nairobi(1994). PATIENTS: Twenty four consecutive patients with symptomatic severe pure mitral stenosis (less than 2+ mitral regurgitation) and suitable mitral valve apparatus(leaflets, chordae and papillary muscles) for successful commissurotomy. INTERVENTION: Percutaneous mitral baloon valvotomy under local anaesthesia. Standard left and right heart catheterisation for mitral valve disease. Transeptal left atrial entry using standard septal puncture technique and left ventricle position secured by single long-stiff guide-wire. Double-baloon mitral valvotomy on single guide-wire using multi-track baloon catheters. MAIN OUTCOME MEASURES: Mitral valve area, left atrial pressures, mitral regurgitation grade. RESULTS: Mitral valve area increased from 0.65 +/- 0.15cm2 to 1.98 +/- 0.34cm2 (P < 0.01), left atrial pressures from 30.5 +/- 9.1 to 11.9 +/- 5.1mmHg (P < 0.01). No significant change in mitral regurgitation grades. No complications related to multi-track technique. CONCLUSION: Percutaneous baloon mitral valvotomy using the multi track technique is effective and safe.

Adolescent↗
PubMed1999

Effect of percutaneous balloon mitral valvotomy on pulmonary venous flow in severe mitral stenosis.

OBJECTIVE: To study the effect of percutaneous balloon mitral valvotomy (PBMV) on the deranged systolic and diastolic pulmonary venous flows in mitral stenosis. DESIGN: Open, non-randomised, case-control study. SETTING: Mater Misericordiae Cardiac Catheterisation Laboratory and Kenyatta National Hospital Cardiac Catheterisation Laboratory. PATIENTS: Twelve consecutive patients with severe symptomatic mitral stenosis with valve characteristics suitable for PBMV on echocardiographic evaluation. INTERVENTION: Percutaneous baloon mitral valvotomy. MAIN OUTCOME MEASURES: Peak systolic and diastolic pulmonary flow velocities and velocity time integrals (VTI). RESULTS: Peak sytolic pulmonary flow velocity increased from 29.8 +/- 9.6 to 46.1 +/- 8.5 cm/s p < 0.01) and systolic VTI from 2.6 +/- 1.0 to 5.5 +/- 0.9 cm (p < 0.01). Peak diastolic flow velocity increased from 39.3 +/- 5.7 to 43.0 +/- 6.9 cm/s (p < 0.05) and diastolic VTI from 3.9 +/- 1.5 to 4.8 +/- 1.6 cm (p < 0.05). Mean mitral valve area increased from 0.65 +/- 0.15 to 1.98 +/- 0.34 cm2 (p < 0.001) and mean left atrial pressures from 30.5 +/- 9.1 to 11.9 +/- 5.1 mmHg (p < 0.001). CONCLUSIONS: In patients with severe mitral stenosis and sinus rythm, left atrial filling is biphasic with diastolic preponderance. Successful PBMV causes predominant increase in atrial systolic filling.

Adolescent↗
PubMed1998

Relation of genotype 22q11 deletion to phenotype of pulmonary vessels in tetralogy of Fallot and pulmonary atresia-ventricular septal defect.

OBJECTIVE: To compare the morphology of the pulmonary vessels in tetralogy of Fallot or pulmonary atresia-ventricular septal defect (PA-VSD) with (del22q) and without 22Q11 deletion (non-del22q). PATIENTS: 94 consecutive infants (54 with tetralogy of Fallot, 40 with PA-VSD) were studied using ultrasound and catheterisation. MOLECULAR INVESTIGATIONS: Identification of the 22q deletion was performed either by fluorescent in situ hybridisation or polymerisation chain reaction genotyping. RESULTS: 25 patients were del22q (16/40 (40%) PA-VSD v 9/54 (17%) tetralogy of Fallot; p < 0.02). Major aortopulmonary collateral arteries was more common in patients with PA-VSD-del22q (p < 0.03). Such collaterals were identified in 13 patients: 10 del22q and three non-del22q (p < 0.001). The size of the right and left pulmonary arteries expressed as a standard deviation (SD) difference of the normal range was -4.2 (quartiles -5.3 and -2.9) for PA-VSD del22q, and -2.6 (-3.1 and -1.8) for PA-VSD non-del22q (p = 0.02). The mean (SD) difference between the measured and theoretical Nakata index was -373 (94) for PA-VSD del22q v -245 (93) in PA-VSD non-del22q (p = 0.0002). In tetralogy of Fallot patients with and without del22q, the size of the pulmonary arteries was similar (p = 0.6). CONCLUSIONS: A "specific" phenotype could be defined in patients with deletion: PA-VSD, major aortopulmonary collateral arteries with complex loop morphology, and small central pulmonary arteries. Differences in the morphology of the pulmonary vessels may indicate a different timing of the faulty developmental pathway in patients with and without 22q11 deletion.

Aorta↗
PubMed1998

Maintaining tricuspid valve competence in double discordance: a challenge for the paediatric cardiologist.

OBJECTIVES: To establish the prevalence of tricuspid valve abnormalities in children with a double discordant heart (or congenitally corrected transposition of the great arteries); to study the influence of the loading conditions induced by various surgical interventions on the right and left ventricle in patients with double discordance and an abnormal tricuspid valve; and to propose a rational surgical approach. METHODS: Case notes were reviewed of 141 consecutive patients admitted in the first year of life with various types of double discordance (intact ventricular septum (group 1), ventricular septal defect (group 2), ventricular septal defect and pulmonary obstruction (group 3)). A study group of 62 patients with an abnormal tricuspid valve was selected by cross sectional echocardiography. These were followed up through palliative and open heart procedures with grading of tricuspid regurgitation. RESULTS: Tricuspid valve abnormalities were more common in groups 1 and 2 (60% and 56%) than in group 3 (31%). Preoperative tricuspid regurgitation was more common in group 2 (90%) than in groups 1 and 3 (38% and 36%). Ten patients in groups 1 and 2 died in the neonatal period with severe tricuspid regurgitation, associated with coarctation of the aorta in 60%. Eight patients in group 1 had no surgery and are doing well, with a competent tricuspid valve. Palliative procedures were undertaken in 28 patients: 14 had pulmonary artery banding, which resulted in a decrease in tricuspid regurgitation, 12 in group 2 by reducing the pulmonary blood flow and two in group 1 by changing the septal geometry; 14 in group 3 had an aortopulmonary shunt, which induced tricuspid regurgitation in two. Twenty patients are still alive after palliation, with stable tricuspid valve function. Repair of the tricuspid valve was unsuccessful in the three patients who underwent conventional surgery, leaving the right ventricle facing the systemic circulation. In two patients with a competent but abnormal tricuspid valve, conventional surgery induced severe tricuspid regurgitation. Of the 15 patients who underwent conventional surgery, only 10 survived (mortality 33%): eight with a tricuspid valve prosthesis and two with severe residual tricuspid regurgitation. However, tricuspid regurgitation decreased after anatomical correction (nine patients), restoring a systemic left ventricle and a subpulmonary right ventricle, even when the tricuspid valve was not repaired (five patients). Eight patients are doing well after anatomical correction (mortality 11%). CONCLUSIONS: Tricuspid valve function in double discordance with an abnormal tricuspid valve depends on the loading conditions of both ventricles and on the septal geometry. Interventions that increase right ventricular volume or decrease left ventricular pressure are likely to induce tricuspid regurgitation, while those that decrease right ventricular volume or increase left ventricular pressure are likely to improve tricuspid valve function. Repair of the tricuspid valve always failed when the right ventricle was left in a systemic position and always succeeded when the right ventricle was placed in a subpulmonary position. These results should be taken in to account when dealing with patients with double discordance and an abnormal tricuspid valve.

Female↗
PubMed1998

[A pulmonary vascularization study in pulmonary atresia with an interventricular defect in relation to the presence of a chromosome 22 deletion].

A normal lung is supplied by a pulmonary artery branching from the pulmonary trunk. Major aorto-pulmonary collateral arteries (MAPCAs) are found in combination with various congenital heart malformations such as pulmonary atresia with ventricular septal defect (PA-VSD). Now that MAPCAs are used for unifocalization in patients with PA-VSD, the question arises as to whether the morphologic criteria of these collateral arteries could help to provide better results. We compared the morphology of the pulmonary vascular bed, the origin, course and connections of the MAPCAs in 40 consecutive infants with PA-VSD with or without 22q deletion (del22q11.2.). All underwent echocardiographic evaluation and catheterization. Identification of del22q11.2. was performed by FISH study. Del22q11.2. was identified in 16 pts (40%); the presence of MAPCAs was significantly higher in patients with del22q11.2. (9/16 vs 3/24, p = 0.01). While complex morphology of MAPCAs, anastomoses with the central pulmonary artery outside the lung and absent ductus arteriosus were associated with del22q11.2, confluence of the pulmonary arteries was not a relevant phenotypic difference. The size of the right and left pulmonary arteries expressed as a standard deviation difference of the normal range for body surface area was -4.2 (quartiles -3.1/-1.8) for PA-VSD with del22q11.2. and -2.6 (quartiles -5.3/-2.9) for PA-VSD without del22q11.2. (p = 0.02). The difference between measured and theoretical Nakata index was -373 +/- 94 for PA-VSD with del22q11.2. vs. -245 +/- 93 for PA-VSD without del22q11.2. (p = 0.0002). A specific pulmonary vascular bed phenotype could be defined in patients with PA-VSD with del22q11.2. deletion: MAPCAs with complex loop morphology and small but confluent central pulmonary arteries. These findings indicate a different timing of the faulty development pathway of the pulmonary vascular bed in patients with and without del22q11.2. This phenotype difference may help our understanding of maldevelopment and facilitate decisions concerning the suitability of these arteries for unifocalization procedures.

Angiography↗
PubMed1998

[Anatomic evaluation of ostium secundum atrial septal defects by tridimensional echocardiography].

The decision to close an ostium secundum atrial septal defect by interventional catheterisation implies knowing its size, form and the relationship of its borders to neighbouring structures as accurately as possible. Three-dimensional echocardiography provides unique views of the interatrial septum and the authors set out to assess its performance. Ten patients, aged 8 to 20 years, included in a multicenter European clinical trial of closure of atrial septal defects with the CardioSEAL prostheses, were examined by transoesophageal echocardiography with three-dimensional reconstruction of the interatrial septum viewed from the left or right atrium. The septal defect had a very variable morphology, round, oval raquet-shaped and occasionally multiple. The surface area of these defects varied by about 70% during the cardiac cycle, maximal during ventricular systole and minimal during atrial systole. The maximal diameter measured by two-dimensional transoesophageal echocardiography underestimated that measured by three-dimensional echocardiography by about 30%. Two patients had a juxta-aortic caudal border or a juxta-superior vena caval cephalic border making the defect unsuitable for catheter insertion of a CardioSEAL occluder. On the other hand, another patient had an adequate juxta-aortic border although it seemed too narrow with conventional imaging techniques. The authors conclude that three-dimensional reconstruction of transoesophageal echocardiography is the best method of selecting candidates for closure of ostium septum atrial septal defect by intervantional catheterisation.

Adolescent↗
PubMed1998

[Can partial cavo-pulmonary connection be considered an alternative to the Fontan procedure?].

The disappointing long-term results of the Fontan procedure led the authors to assess substitution with partial cavo-pulmonary connections for definitive palliative treatment of single ventricle malformations. One hundred and fifteen patients with a mean age of 4.3 +/- 4.5 years (1 month-22 years) were treated by termino-lateral anastomosis between the superior vena cava and corresponding pulmonary artery, either of necessity because of a contraindication to total cavo-pulmonary connections (31 cases) or electively (84 cases). Another source of pulmonary flow was preserved or added in 76% of children, the operative mortality was 4% and the secondary mortality 3.5%. Significant complications were observed in 15% of cases with a secondary morbidity of 13%. Reoperation was required in 18 cases (16%). In fact, the death rate was higher in indications of necessity (19 versus 3.6% in elective procedures). Similarly, the number of serious complications (veno-venous or pulmonary arterio-venous fistulae, ventricular dysfunction) was higher in this group than in patients undergoing an elective procedure (23 versus 2.4%). After 4.8 +/- 3.2 years' follow-up, 73% of children treated of necessity and 95% of children treated electively were well despite mild cyanosis (average saturation of 86 +/- 6%). On condition that these results are confirmed at long-term as present follow-up is relatively short, this strategy would seem to be justified, providing mild cyanosis with little functional impairment is accepted, so avoiding the serious complications of Fontan-like circulations.

Adolescent↗
PubMed1998

[Aortocoronary bypass in children. Apropos of 6 cases].

The improvement in diagnostic techniques for myocardial ischaemia and in imaging of coronary anomalies in children has increased the number of coronary revascularisation procedures. Moreover, the indications are more diverse with the emergence of acquired coronary disease which was unknown until recently, related to operations comprising manipulation of the coronary arteries. The authors report their experience of 7 internal mammary artery bypass grafts in 6 children aged 3 days to 11.5 years (average 2 years): 3 left main coronary stenosis after arterial switch for transposition of the great arteries, 1 peroperative lesion of an intramural left coronary in a case of simple transposition of the great arteries, 1 congenital atresia of the right ostium associated with Tetralogy of Fallot, and 1 right coronary occlusion with giant aneurysms of the left coronary in a case of Kawasaki's disease. There were no operative fatalities. All the coronary grafts were patent at early postoperative control. These results indicate clearly that the method is very feasible from a very early age. Long-term patency, the growth of the anastomosis and of the distal vessels are questions which await a reply in the future.

Child↗
PubMed1997

Atrio-ventricular valve dysplasia in 22 newborn infants.

We retrospectively studied the experience of our institution with isolated dysplasia of one or both atrio-ventricular valves in 22 newborn infants. All patients with associated cardiac malformations were excluded. Ten patients exhibited isolated tricuspid valve dysplasia. One patient had tricuspid valve dysplasia and a dysplastic pulmonary valve. In 10 patients, both atrio-ventricular valves were affected. Finally, mitral valve dysplasia was associated with pulmonary valve stenosis in 1 case. Associated syndromes and/or chromosomal anomalies were: Down syndrome (n=2), trisomy 18 (n=1), Noonan syndrome (n=1), Marfan syndrome (n=3), Ehlers-Danlos and Cutis laxa (n=2). Mortality was 27.2% during follow-up (mean 51 months): 3 patients with chromosomal aneuploidies, 2 patients with severe neonatal Marfan syndrome and 1 with Ehlers-Danlos. Complications were: sustained supra-ventricular tachycardia in 3, neonatal staphylococcal tricuspid valve endocarditis in 1, persistent significant valvular disease in 8. In the remaining 9 survivors, the dysplasia of the atrio-ventricular valves persists with absent or mild incompetence. Beside obvious chromosomal anomalies, newborn infants with dysplastic valves should be investigated for manifestations of connective tissue disorders. This may help to identify new pleiotropic syndromes which include valvular dysplasia as one manifestation.

Aneuploidy↗
PubMed1997

Progressive left main coronary artery obstruction leading to myocardial infarction in a child with Williams syndrome.

UNLABELLED: We report a 3-year-old child with Williams syndrome in whom the first vascular feature of the syndrome was a myocardial infarction related to the occlusion of the left main coronary artery trunk. This coronary artery occlusion was not associated with supravalvular aortic stenosis. CONCLUSION: This report emphazises that acute vascular events related to systemic artery anomalies may reveal Williams syndrome.

Child, Preschool↗
PubMed1997

Coronary artery obstruction after the arterial switch operation for transposition of the great arteries in newborns.

OBJECTIVES: We sought to describe a large series of coronary artery obstructions after the arterial switch operation for transposition of the great arteries and to discuss their clinical implications. BACKGROUND: Aortic root angiography and myocardial perfusion imaging yield ambiguous results regarding the fate of the coronary artery anastomoses after the arterial switch operation. Late death related to coronary artery obstruction and growth of the translocated coronary arteries are of major concern in these patients. METHODS: Selective coronary artery angiography was performed prospectively in a total of 165 children. RESULTS: A total of 12 coronary occlusions, 8 major stenoses, 6 minor stenoses of the left ostium and 4 stretchings of one coronary artery were identified. Obstructions were more frequent in types D and E (p < 0.001) of the Yacoub and Radley-Smith classification. Coronary obstruction was documented in all patients with electrocardiographic and ultrasound evidence of myocardial ischemia at time of study. Early postoperative ischemia did not predict coronary artery lesion if the patient had fully recovered. Persistent or delayed myocardial ischemia was highly predictive of coronary artery lesions. The incidence of coronary artery obstruction was very high (11 of 35) in patients operated on by a rapidly abandoned technique of single-orifice reimplantation of both coronary artery ostia. CONCLUSIONS: Selective coronary angiography is the most accurate means to assess coronary artery obstruction after the arterial switch operation. Precise diagnosis of coronary artery lesions after this operation will help to elucidate the pathogenesis, develop adequate therapeutic strategies and might indicate how to prevent coronary complications after operation.

Child, Preschool↗
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↗
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↗