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Biomedical subjects

J M Quaegebeur

Publications and source records attributed to J M Quaegebeur.

At least 55 records · Page 3Linked to original sources
PubMed1990

Comparative roles of intraoperative epicardial and early postoperative transthoracic echocardiography in the assessment of surgical repair of congenital heart defects.

In 94 consecutive patients undergoing surgical repair of congenital heart defects the results of intraoperative (after cardiopulmonary bypass) epicardial two-dimensional and Doppler color flow imaging were compared with those of sequential transthoracic echocardiography performed within 24 h of surgery and again before hospital discharge to define the precise role of intraoperative imaging. In 6 of 7 patients with a residual defect requiring immediate surgical revision, intraoperative imaging correctly identified the defect; spectral Doppler imaging underestimated or did not identify a residual outflow tract gradient in 17 patients. Left atrioventricular (AV) valve regurgitation after repair of complete AV septal defect was underestimated in three patients. Although intraoperative documentation of good ventricular function was usually associated with a good outcome, in three patients poor systemic ventricular function after cardiopulmonary bypass was not associated with early mortality. A minor degree of shunting around the patch was a common finding on epicardial and early postoperative imaging and persisted at the time of hospital discharge in 17 of 46 patients who had undergone patch closure of a ventricular septal defect as part of the surgical procedure. Additional trabecular septal defects were missed on color flow imaging after cardiopulmonary bypass in three patients, one of whom required subsequent reoperation. Although intraoperative two-dimensional and color flow imaging permitted the recognition of the majority of residual defects requiring immediate revision, residual outflow obstruction or AV valve regurgitation was usually underestimated.

Child↗
PubMed1990

Coronary artery fistula as source of pulmonary circulation in pulmonary atresia with ventricular septal defect.

Four patients are described with pulmonary atresia and ventricular septal defect, in whom the pulmonary circulation was dependent on a fistula from the left coronary artery to the pulmonary artery. The issue in this complex anomaly is complete preoperative diagnosis, including anatomic information on the coronary artery fistula and the pulmonary vasculature. This was achieved in the last 2 patients. In the last patient echocardiography turned out to be an important diagnostic tool in this rare anomaly and facilitated selective angiocardiography. All 4 patients were successfully operated by closing the fistula, closing other aortopulmonary connections and inserting a valved conduit between right ventricle and pulmonary artery. The ventricular septal defect was closed in 3 patients with a patch. In the setting of an already existing pulmonary hypertension and a possibly inadequate pulmonary arterial system at surgery, a perforated patch was inserted in the ventricular septal defect of the remaining patient.

Adolescent↗
PubMed1990

Influence of electrogenic Na/Ca exchange on the action potential in human heart muscle.

STUDY OBJECTIVE: The plateau of the action potential in heart muscle is largely due to the inward Ca2+ current, ica; however, Ca2+ extrusion via Na+/Ca2+ exchange may also generate a significant current, ina/ca. The aim was to assess the influence of ina/ca on the action potential in isolated human heart muscle. DESIGN: Action potentials and force of isometric contractions were recorded in ventricular trabeculae. The muscle was subjected to various stimulus patterns, Ca2+ antagonists, and variations in the ionic composition of the extracellular medium. PATIENTS: From 49 patients, aged 0.5 to 14 years, small right ventricular trabeculae were obtained during open heart surgery. The operations concerned corrections of ventricular septal defects. Data presented in this paper were from nine preparations in which action potentials were recorded during several hours. MEASUREMENTS AND MAIN RESULTS: The results confirmed that: (1) the amplitude of the early part of the plateau was depressed by low [Ca2+] and by Ca2+ antagonists, showing that ica dominates this early part; and (2) that low [Na2+] and post-extrasystolic potentiation also depressed the early component of the plateau of the action potential, which can be explained by inactivation of ica due to increased levels of intracellular Ca2+. A novel observation was that post-extrasystolic potentiation led to an increase in action potential duration (APD). An explanation is that the potentiated contraction follows from an increased amount of intracellular Ca2+ which also activates an inward current, possibly ina/ca. This assumption is strengthened by the finding that lengthening of APD after extrasystoles was abolished: (a) at low [Ca2+], ie, when force was small and there was little Ca2+ to be extruded; and (b) at low [Na+], ie, when force was large but the driving force of the Na+ gradient for extrusion of Ca2+ was small. CONCLUSIONS: The early part of the plateau is dominated by ica, whereas ina/ca is relatively more important during the later part, and tends to lengthen the action potential.

Action Potentials↗
PubMed1990

Juxtaductal pulmonary artery coarctation. An underestimated cause of branch pulmonary artery stenosis in patients with pulmonary atresia or stenosis and a ventricular septal defect.

An angiographic and clinical study was performed to establish the prevalence of juxtaductal pulmonary artery coarctations in patients with pulmonary atresia or stenosis and a ventricular septal defect or a complex intracardiac defect. The present study is an adjunct to a previously reported portmortem study, in which the incidence of these pulmonary artery coarctations was found to be unexpectedly high. Pulmonary artery coarctations were identified angiographically in 10 of the 15 patients with pulmonary atresia. One additional patient had a bilateral ductus arteriosus and confluent pulmonary arteries, but did not have a pulmonary artery coarctation. Pulmonary artery coarctations were much less prevalent in the cases with pulmonary stenosis (5/50). However, these pulmonary artery coarctations appeared identical to those of the cases with pulmonary atresia. Fourteen pulmonary artery coarctations were located in the pulmonary artery at the side of the ductus arteriosus; this was left sided in 12 and right sided in two patients. In one patient the side of the ductus could not be established. The types and the locations of the pulmonary artery coarctations in the present study were identical to those in the previous postmortem study. Ductal tissue was found in many of the pulmonary artery coarctations of the postmortem study and is likely to be present in the clinical cases as well. The majority of the angiographically identified pulmonary artery coarctations were subsequently confirmed at operation or at autopsy. The clinical outcome and follow-up of the patients is discussed, and it is concluded that juxtaductal pulmonary artery coarctations should be specifically looked for before and during any type of surgical intervention in these patients.

Constriction, Pathologic↗
PubMed1989

Anatomic correction for transposition of the great arteries: first follow-up (38 patients).

Between April 1983 and October 1985, 38 consecutive patients with transposition of the great arteries (TGA) underwent anatomic correction. Ages ranged from 1 day to 284 weeks (mean 26.2 weeks). Simple TGA was present in 17 patients, 17 had an associated ventricular septal defect, and the remaining four had a Taussig-Bing anomaly. Hospital mortality was 2 of 38, with 1 late death. Follow-up time varied from 6 to 35 months. Postoperative cardiac catheterization was performed in 34 of the 36 early survivors. Right ventricular outflow tract obstruction with a systolic gradient greater than 20 mmHg was found in four. A residual left-to-right shunt was found in nine; Qp/Qs exceeded 2.0 in only one. In four, the pulmonary-to-systemic resistance ratio calculated was greater than 0.3. All 35 survivors are in excellent condition. Only one patient has slight aortic insufficiency. Most pre- and postoperative electrocardiographic abnormalities disappeared in due course. Echocardiography revealed normal left ventricular dimensions and fractional shortening. The aortic root diameter showed in almost all a value above the 95th percentile of normal. Postoperatively, the aortic root has grown parallel to, but above, the 95th percentile and as yet has shown no tendency to normalization.

Angiocardiography↗
PubMed1989

Myocardial (iso)enzyme activities, DNA concentration and nuclear polyploidy in hearts of patients operated upon for congenital heart disease, and in normal and hypertrophic adult human hearts at autopsy.

To investigate biochemical characteristics of hypertrophic myocardium of young and adult humans, we analysed myocardial biopsies obtained from 28 mainly young patients undergoing cardiac surgery for congenital heart disease and 41 autopsied hearts from 18 adult normal and 23 hypertrophic human subjects. Myocardial activities of the enzymes creatine kinase and lactate dehydrogenase were independent of age during childhood, but decreased significantly with hypertrophy at adult age. Myocyte nuclei showed increased polyploidization during childhood which was progressive with age, and in the adult stage polyploidization was correlated with heart weight. Nevertheless myocardial DNA concentration fell under both conditions, which is to be ascribed to the 'diluting' effect of myocyte hypertrophy. Before an age of 8 years DNA concentration in the child heart material studied has reached the value found in adult nonhypertrophic hearts, although at that time polyploidization of myocyte nuclei in child hearts was only half the value found in adult non-hypertrophic hearts. Biochemical measurement of DNA concentration in peroperatively taken myocardial biopsies may contribute to the in vivo diagnosis of ventricular hypertrophy in quantitative terms, in combination with radiology, echocardiography and histology.

Adolescent↗
PubMed1988

Assessment of hypertrophy in myocardial biopsies taken during correction of congenital heart disease.

Myocardial biopsies were obtained from 27 patients undergoing corrective cardiac surgery for congenital heart disease. Normal hearts of 18 autopsied patients were used as reference. The biopsy material was assessed for desoxyribonucleic acid (DNA) concentration and ploidy profile of cell nuclei in order to quantitate myocardial hypertrophy at the time of operation. DNA-concentration decreased significantly with age (r = -0.76; p less than 0.001). Ploidy profile of myocardial nuclei correlated with age: the relative number of diploid nuclei decreased (r = -0.67; p less than 0.001), the relative numbers of tetraploid and octoploid nuclei increased with age (r = 0.58; p less than 0.01 and r = 0.77; p less than 0.001 respectively). At 8 years of age the patients with congenital heart disease reached myocardial DNA-concentrations comparable with those in normal adult hearts. At higher age the patients with congenital heart disease exceeded normal adult values for myocardial DNA-concentration. These findings are interpreted to represent rapid development of hypertrophy with an early onset, reaching at 8 years of age values observed in normal adult hearts. Quantitation of myocardial hypertrophy by DNA-concentration and ploidy profile of nuclei may offer a means to explain some of the factors of influence on the outcome of corrective cardiac surgery for congenital heart disease in relation to its timing. Our data stress the need for preventing irreversible myocardial damage by timely (surgical) therapy.

Adult↗
PubMed1988

Doppler mapping of postoperative left atrioventricular valve regurgitation.

Left atrioventricular valve regurgitation often occurs as a postoperative hemodynamic complication from repair of an atrioventricular septal defect. In this study, cross-sectional two-dimensional Doppler flow mapping of the left atrium was used to quantify postoperative regurgitant flow in 29 patients. Its severity and location was related to the shape of the three leaflets of the left component of the atrioventricular valve, especially to the size of the mural leaflet. To identify which leaflet configuration was likely to cause regurgitation, the position of the leaflets was obtained from the parasternal short-axis view and the angular size of the mural leaflet expressed in degrees of an arc. Doppler mapping was performed in the apical four-chamber and the parasternal long-axis views, dividing the left atrium in nine squares in each. Regurgitation was defined as a jetlike systolic downstroke of the Doppler frequency shift in early systole. The angular size of the mural leaflet varied from 38 to 144 degrees (mean 86 +/- 36 SD). Massive regurgitation (six to nine sites) was encountered in seven patients, five with a mural leaflet size of over 110 degrees, one with mural leaflet size between 70 and 110 degrees, and one with a mural leaflet size of under 70 degrees. No or minimal regurgitation was encountered in 10 patients, three having a mural leaflet size of 70 to 110 degrees and seven with a mural leaflet size of less than 70 degrees. These data suggest that massive regurgitation is encountered in patients with large mural leaflets, whereas patients with smaller mural leaflets tend to have no or mild regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1987

Mediastinal rupture of a thoracoabdominal mycotic aneurysm caused by Salmonella typhimurium in an immunocompromised patient.

A case is presented of rupture of a mycotic thoracoabdominal aneurysm caused by Salmonella typhimurium in a patient on immunosuppressive therapy following kidney transplantation. After initial medical treatment, surgery consisted of local debridement and implantation of an aortic prosthesis. Lifelong antibiotic treatment was prescribed because of the combination of immunosuppressive therapy, the history of recurrent S. typhimurium bacteremia and the presence of an aortic prosthesis.

Aneurysm, Infected↗
PubMed1987

Early and late results of surgical treatment of congenital coronary artery fistula.

The early and late results of surgical treatment in 23 patients with congenital coronary artery fistula (CCAF) are presented. One patient died for reasons unrelated to the fistula during corrective surgery for an associated complex cyanotic abnormality. The patients with isolated CCAF and preoperative symptoms improved significantly after surgical closure of the CCAF (p less than 0.05). We conclude that all symptomatic patients with CCAF should be treated with surgical closure of the fistula.

Adolescent↗
PubMed1986

The arterial switch operation. An eight-year experience.

Sixty-six patients (23 neonates with transposition of the great arteries and intact ventricular septum, 33 infants and children with transposition and a large ventricular septal defect, and 10 with double-outlet right ventricle with a subpulmonary ventricular septal defect have received an arterial switch repair since 1977. Eight (one with transposition and intact ventricular septum, six with transposition and ventricular septal defect, and one with double-outlet right ventricle with subpulmonary ventricular septal defect) died in the hospital. All other patients have had follow-up as of June, 1985. Including the hospital deaths, the 11 month actuarial survival rate for the entire group was 81%, and no deaths have occurred among the 33 patients alive at that time and traced as long as 8 years. The hazard function for death has only a single early phase, and its 70% confidence limits overlap the hazard function of a matched general population by 12 months after the operation. Incremental risk factors for death included low birth weight (but not weight or age at operation), transposition of the great arteries with large ventricular septal defect, double-outlet right ventricle with subpulmonary ventricular septal defect, and presence of a patent ductus arteriosus. Coronary artery morphology and position of the great arteries were not risk factors. Long aortic cross-clamp time was possibly (p = 0.11) a risk factor. Early date of operation was a risk factor (p = 0.004); thus, predicted 1 year survival rate, including hospital deaths, after the arterial switch operation in 1985 is 99.9% (70% confidence limits 99.0%-100%) for neonates with transposition and intact ventricular septum and 99.7% (98.4%-99.9%) for those with transposition and a large ventricular septal defect or double-outlet right ventricle. The late functional status was excellent, and the rhythm was sinus in 96% of the 55 surviving patients. A formal comparison with the results of the atrial switch repair indicates that the arterial switch repair is superior.

Aorta↗
PubMed1985

Tricuspid atresia. Morphology of the outlet chamber with special emphasis on surgical implications.

An anatomic study of 28 heart specimens with tricuspid atresia showed 15 hearts with ventriculoarterial concordance and a right-sided anterior outlet chamber. Of these 15 hearts, 12 showed evidence of restricted pulmonary blood flow. In eight of these 12 specimens, an anterior deviation of the outlet septum, relative to the primary septum, was present. This deviation caused a narrowing inside the outlet chamber and functioned as infundibular pulmonary stenosis. The outlet chambers of the 15 hearts with ventriculoarterial concordance were compared with those of 13 hearts with tricuspid atresia and ventriculoarterial discordance and also a right-sided anterior outlet chamber. In the latter group of 13 hearts, five showed evidence of restricted pulmonary blood flow, at least partially caused by posterior deviation of the outlet septum relative to the primary septum. A clear difference in outlet chamber morphology was found without exception between specimens with and without ventriculoarterial concordance. Clinical data in three long-term survivors of the Fontan procedure demonstrate that the special morphology of the outlet chamber can pose surgical problems. Especially in patients with ventriculoarterial concordance, when the outlet chamber is incorporated into the pulmonary circuit, the surgeon must give special attention to the specific morphology to prevent undesirable sequelae.

Adolescent↗
PubMed1984

Double-inlet ventricle: morphologic analysis and surgical implications in 32 cases.

We analyzed, using a sequential segmental approach, 32 cases of double-inlet ventricle to assess the feasibility of surgical "correction" by either ventricular septation or a modified Fontan procedure. Twenty-two hearts had two atrioventricular valves, connected to a left ventricle in 19, a right ventricle in two, and a solitary indeterminate ventricle in one. Septation was possible in only 13. In contrast, the Fontan procedure seemed feasible in 20. The remaining 10 specimens had double inlet via a common valve to the left ventricle in two, the right ventricle in six, and an indeterminate ventricle in two. Seven of these had right atrial isomerism. Ventricular septation was not considered a possibility in these hearts. The Fontan procedure combined with atrial septation was a possibility in seven cases. From the morphologic stance, although the modified Fontan procedure seemed suitable in most cases, a significant number of hearts with two atrioventricular valves were suitable for ventricular septation.

Endocardial Cushion Defects↗
PubMed1983

Growth of an aorta-coronary anastomosis. An experimental study in pigs.

The influence of growth of an aorta-coronary anastomosis, comparable to the coronary translocation anastomosis during the arterial switch operation, was studied in pigs. The anastomosis between the right coronary artery and the aorta did not grow, and this lack of growth may result in stenosis. With another technique, by which the coronary artery was excised with a cuff of aortic wall, the effects caused by absence of growth were circumvented and a normal-sized coronary ostium was present after growth. However, when no cuff was used, stenosis occurred at the suture line and caused growth retardation of the animal as well as histologic damage to the right ventricle.

Animals↗