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Biomedical subjects

M L Rigby

Publications and source records attributed to M L Rigby.

At least 37 records · Page 2Linked to original sources
PubMed1997

Transcatheter umbrella closure of aorto-pulmonary window.

Aorto-pulmonary window (aorto-pulmonary septal defect) is an uncommon congenital cardiac malformation which is repaired using cardiopulmonary bypass. A case is described of an infant with a small aorto-pulmonary window which was closed by transcatheter insertion of a double umbrella device. Complete occlusion of the defect was achieved without complications. Transcatheter umbrella closure of a small aorto-pulmonary window is feasible in infancy and the technique is likely to be applicable in a few cases.

Aortography↗
PubMed1997

Anatomical criteria for the diagnosis of sinus venosus defects.

BACKGROUND: The diagnosis of sinus venosus defects remains a matter of debate. It is crucial to provide solid anatomical criteria, by identifying the very nature of the atrial septum relative to sinus venosus defects, to diagnose and differentiate them from other interatrial communications. OBJECTIVE: This study was designed to reestablish the anatomical criteria for the diagnosis of sinus venosus defects. METHODS: Five specimens with sinus venosus defects from the cardiopathological museum were examined. Study of the abnormal hearts was supplemented by examining the extent and structure of the atrial septum in 10 normal hearts. The echocardiograms and surgical notes were reviewed from 18 patients seen between July 1991 and August 1996 at the Royal Brompton Hospital in London diagnosed preoperatively to have a sinus venosus defect. RESULTS: The nature of the oval fossa and its muscular borders were identified in the normal hearts. In all three autopsied specimens of the superior variety of sinus venosus defect, the mouth of the superior caval vein was overriding the intact muscular anterosuperior border of the oval fossa. Two specimens thought initially to have the inferior variety of sinus venosus defect were re-classified as having defects within the oval fossa as it was the deficient oval fossa itself, rather than its intact muscular border, that was overridden by the mouth of the inferior caval vein. Sixteen patients had been diagnosed echocardiographically as exhibiting the superior variant of the defect. Retrospective review showed overriding of the superior caval vein across the upper rim of the oval fossa in 12 patients. These findings were confirmed by surgery in 11 patients with the 12th awaiting operation. Overriding of the fossa by the caval vein was not found in the other four patients. Surgery in all of these showed the defect to be within the oval fossa. In two patients diagnosed echocardiographically as having inferior defects, the surgical findings confirmed a biatrial connection of the inferior caval vein in one patient, the findings in the second were equivocal. CONCLUSIONS: The key anatomical criterion for the diagnosis of sinus venosus defects is overriding of the mouth of the superior or inferior caval vein across the intact muscular border of the oval fossa. The interatrial communication is then formed within the mouth of the overriding vein, and is outside the confines of the oval fossa.

Adolescent↗
PubMed1996

Open-access paediatric echocardiography: changing role and referral patterns to a consultant-led service in a tertiary referral centre.

OBJECTIVES: To evaluate the changing role of an open-access consultant-led paediatric echocardiography service for the detection and assessment of cardiac disease in children. DESIGN: A retrospective analysis comparing two patient groups undergoing echocardiography over two corresponding six month periods in 1989 and 1994. SETTING: A tertiary referral centre. MAIN OUTCOME MEASURES: Patient demographics, indication for echocardiogram, source of referral and findings on scan in new referrals, subsequent follow up arrangements. RESULTS: The total workload increased by 51% over 5 years but in 1994 fewer neonates were scanned. Patients were referred by hospital paediatricians, community paediatricians, and general practitioners and the number of "new referrals" as a percentage of the total number of patients scanned remained constant. The number of children referred with asymptomatic murmurs who had "normal" echocardiograms increased. Fewer patients were referred directly for surgery in 1994, but the number of children referred for interventional catheterisation rose. CONCLUSIONS: Open-access echocardiography has an expanding role in the tertiary referral centre despite increasing availability of echocardiography facilities in local hospitals and increased demand in local outreach clinics with paediatricians. Asymptomatic murmurs continue to be the single most common reason for referral of "new patients" and many scans are used to confirm the clinical suspicion of a "normal" heart. The appropriateness of using echocardiography as a screening procedure must be questioned where it would be more logical to refer only the children who present diagnostic difficulty. None the less these data confirm the impression of increasing demands on the paediatric cardiologist, and thus may be useful in planning consultant services within the specialty.

Ambulatory Care↗
PubMed1995

Interventional catheterization in paediatric cardiology.

The primary role of interventional procedures in the management of some congenital heart diseases is established and their clinical utility broadens every day. Yesterday's relatively crude procedures have been replaced by safe and more effective techniques. Improvements and new developments in specifically designed paediatric equipment have played a significant role. In order to meet the cardiologist's drive to refine existing techniques and develop new ones, further investment into paediatric cardiac catheterization equipment is mandatory. More and more "heart operations' will be performed in cardiac catheterization laboratories in the future, and this will have clear implications on costs, as most non-surgical techniques are cheaper than surgery, and hospitalization is much shorter. New methods, tested within research protocols in specialized centres, combined with continuous critical evaluation of established techniques will ensure improved and sustained results. The primary consideration of practising paediatric cardiologists should not be whether it is possible to perform such techniques, but whether their clinical utility, morbidity and mortality justifies a non-surgical approach for their centre. Interventional catheterization, in other words has to "compete' with the results of surgery prior to new techniques being recommended for general use. Despite this "competition' it has been welcome to see a collaboration between paediatric cardiologists and paediatric cardiac surgeons in planning staged repairs of complex congenital heart disease. A typical example of this is the fenestrated Fontan procedure, in which the immediate post-operative course has dramatically improved due to the deliberate placement of a residual atrial shunt, which is then closed with an umbrella in the catheter laboratory. This type of cooperation is bound to increase further and is already contributing to a far better outcome for many of the complex congenital heart lesions.

Angioplasty, Balloon↗
PubMed1995

Contemporary results of balloon valvuloplasty and surgical valvotomy for congenital aortic stenosis.

The purpose of this study was to compare contemporary results of balloon dilatation and surgery for valvar aortic stenosis in infants and children in the five years between August 1988 and October 1993. Thirty four children underwent attempted balloon valvuloplasty (age 1 day-16 years, weight 1720 g-68 kg) (group 1), eight of whom were neonates with critical aortic stenosis. During the same period, 17 children underwent direct surgical valvotomy (group 2) (seven neonates). Successful balloon valvuloplasty was achieved in 33 (97%) with immediate reduction in the instantaneous systolic pressure gradient from 82 to 34 mm Hg (mean). There were two deaths in this group (both neonates), the second in a preterm neonate from necrotising enterocolitis. Complications requiring intervention in group 1 were aortic regurgitation in one and femoral artery injury in two. Follow up from four months to five years showed sustained results in most cases. There were two neonatal deaths in the surgical group. When the two groups were compared there was no significant difference in mortality, morbidity, or need for reintervention within 12 months. Deaths from both groups were attributed to small left ventricles. Hospital stay was significantly shorter in group 1. It is concluded that balloon dilatation for valvar aortic stenosis is effective and safe for the entire paediatric population. The results compare favourably with those of surgery.

Adolescent↗
PubMed1995

Increasing cyanosis early after cavopulmonary connection caused by abnormal systemic venous channels.

OBJECTIVE: To show that abnormal systemic venous channels in patients who undergo cavopulmonary anastomoses can become manifest and haemodynamically important only after surgery despite detailed preoperative investigation. DESIGN: Descriptive study of patients fulfilling the above criteria selected from hospital records over the past three years. SETTING: A tertiary referral centre. PATIENTS: Of the three cases identified, two were isomeric, one with left atrial isomerism and hemiazygos continuation of the inferior vena cava who underwent bilateral bidirectional Glenn anastomoses and one with right isomerism who underwent total cavopulmonary anastomosis. Case 3 had absent left atrioventricular connection with a hypoplastic left lung and underwent a classic right Glenn procedure. All three cases presented with progressive cyanosis in the early postoperative period. INTERVENTIONS AND RESULTS: Postoperative angiography in case 1 showed a remnant of a left inferior vena cava draining to the atrium to have become grossly dilated causing cyanosis, which resolved after redirection of this vessel and of the hepatic veins into the right pulmonary artery with an intra-atrial baffle. Cyanosis in case 2 was caused by intra-hepatic shunting to a hepatic vein draining to the left of the intra-atrial baffle. The diagnosis was made at necropsy, being overlooked on postoperative angiography. Repeat angiography in case 3 showed progressive dilatation of a small left superior vena cava to coronary sinus. Test occlusion with a view to embolisation revealed hitherto an undemonstrated hemiazygos continuation of inferior caval to brachiocephalic vein. The patient underwent surgical ligation of these two venous channels. CONCLUSIONS: Despite appropriate investigation some "abnormal" venous pathways manifest themselves, dilate, and become haemodynamically important only after surgical cavopulmonary anastomoses. In the presence of early postoperative cyanosis "new" systemic venous collateral channels should be considered as a possible cause, which may require reintervention.

Child↗
PubMed1995

Closure of Blalock-Taussig shunts using a new detachable coil device.

Two children underwent interventional closure of a modified Blalock-Taussig shunt using a new detachable coil system (Duct-Occlud). This procedure has advantages over currently available materials to occlude these and other communications between the systemic and pulmonary circulations.

Arteriovenous Shunt, Surgical↗
PubMed1994

Umbrella occlusion of persistent arterial duct in children under two years.

OBJECTIVE: To assess the use of trans-catheter occlusion of a persistent arterial duct in symptomatic children < 2 years of age. DESIGN: Descriptive study of selected, non-randomised infants with persistent arterial duct who underwent attempted umbrella occlusion. SETTING: Tertiary referral centre. PATIENTS: Between June 1990 and April 1993, 29 young children with a symptomatic persistent arterial duct underwent attempted transcatheter occlusion. Their age ranged from 1.5 to 23 months, with the youngest infant weighing 2.9 kg. The diagnosis was established before operation in all patients by cross sectional echocardiography. INTERVENTION: Transcatheter occlusion of a haemodynamically important persistent arterial duct was performed with the Rashkind ductal umbrella. In the past year the front loading technique has been used to place the 12 mm umbrella through a 6 F (French) sheath and the 17 mm device through a 8 F sheath so extending the indications for their use. RESULTS: Umbrellas were successfully placed in 25 (86.2%) infants and there was symptomatic improvement in all. There were no deaths or severe complications. The four failures occurred early in the series. They were caused by kinking of the 11 F sheath in two cases and embolisation into the left pulmonary artery in one case. The procedure was abandoned in the fourth case because of a large duct. Only three of the 25 patients had small residual shunts at one year follow up (all with 17 mm devices) but no stenosis or turbulence was noted in any of the patients. CONCLUSION: The transcatheter occlusion of persistent arterial duct in young children with symptoms is a safe alternative to surgery. The new front loading umbrella technique enables successful ductal closure in even smaller infants than earlier devices.

Cardiac Catheterization↗
PubMed1994

Primary transcatheter umbrella closure of perimembranous ventricular septal defect.

OBJECTIVES: The starting hypothesis was that some perimembranous ventricular septal defects can be closed safely and effectively with a Bard Rashkind double umbrella introduced through a long transvenous sheath. DESIGN: A descriptive study of all patients who underwent attempted transcatheter umbrella closure of a perimembranous ventricular septal defect. Those patients selected for the study had symptoms of a ventricular septal defect and a perimembranous ventricular septal defect shown by transthoracic echocardiography. The morphological criteria used were a posterior perimembranous defect with a diameter of < or = 8 mm not associated with overriding of the aortic or pulmonary valve or with aortic valve prolapse. The haemodynamic criteria for inclusion in the study were a right to left ventricular systolic pressure ratio of > 0.45, a Doppler derived right ventricular systolic pressure of > 50 mm Hg, and a pulmonary to systemic flow ratio > 3:1. SETTING: A tertiary referral centre. PATIENTS: 13 infants, children, and adolescents with a perimembranous ventricular septal defect aged 3 weeks to 16 years and weighing 1.8-46 kg. INTERVENTIONS: A modified Rashkind ductal double umbrella was introduced through a long transvenous sheath and positioned on either side of the ventricular septal defect. Placement was guided by transoesophageal echocardiography. RESULTS: 10 out of 13 patients underwent successful partial or complete closure of a perimembranous ventricular septal defect. There were three placement failures. Two of these were associated with a ventricular septal defect too large for the umbrella device. In a third case the umbrella was opened in the left ventricular outflow tract necessitating surgical removal and closure of the ventricular septal defect. CONCLUSION: Transcatheter umbrella closure of a perimembranous ventricular septal defect is technically feasible and can be therapeutically successful, although the procedure is moderately difficult to perform and the mean procedure time is > 120 minutes. It is an alternative to surgery in some cases, but the overall results would not support its routine use even with the introduction of larger devices of the current design.

Adolescent↗
PubMed1994

Transcatheter closure of interatrial communications with a modified umbrella device.

OBJECTIVE: To show the institutional experience of closure of interatrial communications with a modified umbrella device. DESIGN: Descriptive study of all patients in whom transcatheter umbrella closure of interatrial communications has been attempted. SETTING: A tertiary referral centre. PATIENTS: 16 patients with 17 interatrial communications of various types. INTERVENTIONS: Transcatheter placement of a modified Rashkind umbrella occluder. RESULTS: Two procedural failures due to venous access problems. Two placement failures needing early surgical repair. 13 successful placements in 12 patients. CONCLUSIONS: The modified Rashkind umbrella can successfully be used to close both iatrogenic and naturally occurring interatrial communications, particularly those present after the Fontan procedure.

Adolescent↗
PubMed1993

Novel uses of the Rashkind ductal umbrella in adults and children with congenital heart disease.

OBJECTIVE: To show possible alternative uses of the Rashkind ductal umbrella. DESIGN: Descriptive study of selected, non-randomised patients; with specific congenital heart lesions other than an arterial duct. SETTING: A tertiary referral centre. PATIENTS: Nine patients with congenital heart lesions; four with interatrial communications after a fenestrated Fontan procedure two with large aortopulmonary collaterals, three with an unoperated ventricular septal defect. INTERVENTIONS: Placement of a Rashkind umbrella occluder as treatment for a haemodynamically important lesion. RESULTS: Successful placement with symptomatic and haemodynamic improvement in all. CONCLUSIONS: The Rashkind ductal umbrella may be used successfully to treat some patients with aortopulmonary collateral vessels, ventricular septal defects, and interatrial communications after the fenestrated Fontan procedure.

Adolescent↗
PubMed1993

Angiographic diagnosis of anomalous coronary artery in tetralogy of Fallot.

OBJECTIVE: To obtain angiographic views in tetralogy of Fallot that can show whether or not an anomalous coronary artery passes anterior to the right ventricular outflow tract. DESIGN: (a) A 10 year retrospective review of all patients who underwent repair of tetralogy of Fallot up to December 1990; (b) a prospective study of 30 children undergoing routine cardiac catheterisation. PATIENTS AND METHODS: 295 cases in whom standard angiographic views had been used were reviewed retrospectively. Thirty non-consecutive children with tetralogy of Fallot were studied prospectively, including one child previously studied in whom diagnosis of an unsuspected anomalous coronary artery was made only at operation. The aortogram was performed with > or = 45 degrees caudocranial and 20 degrees-30 degrees left anterior oblique angles. SETTING: Tertiary referral centre. RESULTS: Ten of the 295 cases reviewed were shown to have a coronary vessel traversing the right ventricular outflow tract. In one case the diagnosis was suspected before operation but it was missed in the others. Even in retrospect we could not be certain of the precise anatomy with the use of standard angiographic views. In the prospective study the caudocranial aortogram showed the aortic valve face on in all the patients. The right ventricular outflow tract lay in a left and anterior (seen as superior) position in relation to the aortic root. Thus any vessel crossing the outflow tract could be identified. Identification of the aortic cusps allowed precise definition of the origin of the coronary arteries. All but four had normal origin and course of the coronary arteries. Four had paired left anterior descending arteries (including the restudied patient), in all cases with a large vessel originating from the right coronary artery passing across the right ventricular outflow tract. CONCLUSIONS: Important anomalies of the coronary arteries in tetralogy of Fallot may remain undiagnosed if standard angiographic projections are used. Aortography with > or = 45 degrees caudocranial and 20 degrees-30 degrees left anterior oblique angles allows precise definition of the anatomy and certainty as to whether any major vessel crosses the right ventricular outflow tract. Interpretation, however, can only be correct if the projection is technically adequate with a view of the aortic valve face on. Furthermore, a normal bifurcation of the left main stem does not exclude a second left anterior descending artery crossing the pulmonary outflow tract.

Child↗
PubMed1992

Right ventricular outflow obstruction by anomalies of the tricuspid valve: report of a windsock diverticulum.

A 9-month-old infant with a clinical diagnosis of double outlet from the right ventricle, subaortic ventricular septal defect, and muscular subpulmonary obstruction underwent surgical repair. The defect was corrected and the right ventricular infundibulum enlarged with a patch. Eight hours after the operation there was a sudden collapse which rapidly progressed to cardiac arrest and death. Postmortem examination of the heart confirmed the clinical diagnosis but noted that the subpulmonary obstruction was caused by a "windsock" deformity of the tricuspid valve which was not identified at operation. The variants of malformations of the tricuspid valve causing subpulmonary obstruction are reviewed.

Heart Septal Defects, Ventricular↗
PubMed1992

Exercise capacity after complete repair of tetralogy of Fallot: deleterious effects of residual pulmonary regurgitation.

OBJECTIVE: To determine the effects of residual pulmonary regurgitation on exercise tolerance after complete repair of tetralogy of Fallot. DESIGN: Prospective study of symptom free patients more than five years after complete repair. Graded exercise performance was measured with standard Bruce protocol. Maximal oxygen uptake and ventilatory anaerobic threshold were measured by respiratory mass spectrometry. Measurement of pulmonary regurgitant fraction was from pressure-volume loops constructed from measurements of right ventricular volume obtained from biplane angiograms and simultaneous pressures measured with a micromanometer. SETTING: Tertiary referral centre. PATIENTS: 16 patients were studied. Two patients had been excluded because of residual cardiac lesions or inadequate data from cardiac catheterisation. Four were later excluded because they failed to reach a respiratory quotient of greater than 1.0 during graded exercise. RESULTS: There was a significant negative correlation between the degree of residual regurgitation and both total duration of exercise and maximal heart rate achieved. Maximal heart rate and total duration of exercise were significantly lower in the patients than in normal controls. Patients with an abnormal maximal oxygen uptake (less than 85% of the predicted normal value) had significantly greater residual pulmonary regurgitation than those in whom oxygen uptake was normal. CONCLUSIONS: Impaired exercise capacity after complete repair of tetralogy of Fallot is directly related to the degree of residual pulmonary regurgitation. These data should be taken into account when deciding the optimal timing and nature of corrective surgery.

Adolescent↗
PubMed1992

Left ventricular performance in children: transthoracic versus transoesophageal measurement of M mode derived indices.

OBJECTIVE: To compare M mode derived indices of left ventricular performance obtained with transthoracic and transoesophageal echocardiography in children with congenital heart disease. DESIGN: Transthoracic and transoesophageal M mode echocardiograms were obtained under general anaesthesia before cardiac catheterisation. Recordings were digitised by dedicated software. Indices of cavity dimension and left ventricular wall dynamics were compared. PATIENTS: 16 unselected patients with congenital heart disease. RESULTS: Group data for simple measurements of ventricular dimension and wall thickness were similar with the two techniques and had acceptable coefficients of repeatability, but there were considerable individual differences. Correlation was poor with unacceptable repeatability for derived indices of cavity and ventricular wall dynamics. CONCLUSION: Both transthoracic and transoesophageal echocardiography can be used to obtain M mode derived indices of left ventricular performance but the resultant measurements are not directly comparable, presumably because of regional non-uniformity of function.

Adolescent↗