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Biomedical subjects

Luc Mertens

Publications and source records attributed to Luc Mertens.

At least 19 recordsLinked to original sources
PubMed2006

Early complications of stenting in patients with congenital heart disease: a multicentre study.

AIMS: Stenting has become an established interventional cardiology procedure for congenital heart disease. Although most stent procedures are completed successfully, complications may occur. This multicentre study evaluated early complications after stenting in patients with congenital heart disease, including potential risk factors. METHODS AND RESULTS: In this combined Dutch-Belgian retrospective study, 309 consecutive patients had undergone 366 catheterizations and received 464 stents in 13 different anatomical positions (418 sites). Seventy-two stenting-related complications (19%) occurred, of which 24 (5.7%) were major. Seven procedure-related deaths were documented (2.3%). Stent malpositioning and embolization were most common (7.7%). The use of non-premounted stents tended to be associated with higher complication rates. Centre inexperience with stenting and stenting of native vs. post-surgical stenosis tended to be associated with increased major complication rates. CONCLUSION: After stenting, complications are common for congenital heart disease. The vast diversity of stenotic sites combined with relatively small patient populations makes these procedures sensitive to complications. Combining operator experience may reduce the risks of stenting in congenital heart disease. The availability of premounted stents for greater vessel diameters will likely reduce incidences of stent migration and embolization.

Adolescent↗
PubMed2006

Ultrasonic strain rate and strain imaging of the right ventricle in children before and after percutaneous closure of an atrial septal defect.

This study examined the influence of preload alterations on systolic right ventricular (RV) velocities and deformation indices in patients with atrial septal defect (ASD). A total of 21 patients with ASD underwent 2-dimensional echocardiography and color Doppler myocardial imaging scan before and 24 hours after transcatheter ASD closure. The data were compared with those obtained from 30 healthy age-matched children. Longitudinal peak systolic velocities, peak systolic strain rate (SR), and end-systolic strain (epsilon) were calculated in the midsegment of the RV free wall and the septum. In patients with ASD, higher RV peak systolic velocities were recorded, which returned to normal values after closure of the defect. In contrast, RV deformation indices in the patients with ASD were not different from normal values. These RV indices did not change significantly after ASD closure. We found a significantly decreased septal function after percutaneous ASD closure. This may be attributed to the device within the atrial septum, affecting deformation of the interventricular septum. In conclusion, RV longitudinal systolic deformation indices were not significantly influenced by chronic ventricular volume overload and sudden abolishment of this volume overload. These findings suggest that SR/epsilon are relatively load-stable measures of contractile function in the clinical setting. In contrast, myocardial velocities are clearly load dependent.

Adolescent↗
PubMed2006

Epicardial pacing: a single-centre study on 321 leads in 138 patients.

OBJECTIVE: This study presents the long-term outcome of 321 epicardial leads in 138 patients. METHODS AND RESULTS: All leads were Medtronic CapsureEpi model 4965 steroid eluting leads. The 1-, 3-, and 5-year patient survival was 91%, 83% and 77%, respectively.Twenty-seven patients died. In 25/27 deaths a pacing-related death could be excluded. Strangulation of the heart by an abandoned epicardial lead was the cause of death in one child. One other patient died suddenly at the age of 3 years. Failures occurred in 57 of 321 epicardial leads (18%). For all 321 leads, the 1-, 3- and 5-year freedom from failure was 91%, 85% and 71%, respectively. The cumulative proportion of patients without any lead defect was 85% after I year, 76% after 3 years and 62% after 5 years. The percentage of patients without serious adverse events at 1, 3, and 5 years was 97%, 91%, 85%, respectively. Lead fracture was the cause of failure in 15 leads of 9 patients. An important increase in pacing threshold occurred in 35 leads of 30 patients. Other failures were: diaphragmatic stimulation, infection, excessive traction and strangulation. Eighteen failures were repaired by 11 surgical interventions in 9 patients.Thirty-nine defects were corrected non-invasively in 31 patients. CONCLUSIONS: The use of steroid-eluting epicardial leads has proven to be an adequate option. In paediatric cardiology, the epicardial approach remains an indispensable tool for achieving a life-long pacing.

Adolescent↗
PubMed2005

Different deformation patterns in intracardiac tumors.

We report on the ultrasound characteristics of two different intracardiac tumors in newborns. The first infant presented with multiple rhabdomyomas in the context of tuberous sclerosis. Ultrasound-based strain and strain rate analysis showed that the tumors deformed in the opposite direction from the surrounding myocardial segments. The second child presented with a large cardiac fibroma as confirmed by pathological examination. In this case strain and strain rate analysis showed the absence of deformation in the tumor. These findings suggest that this new technique could be used to differentiate between different types of myocardial tumors.

Diagnosis, Differential↗
PubMed2005

Acute hemodynamic benefit of left ventricular apex pacing in children.

BACKGROUND: Despite the fact that pacing at the right ventricular apex acutely and chronically decreases left ventricular contractile function, this pacing site is still conventionally used in adults and children. Because animal studies showed beneficial effects of left ventricular pacing, we compared the hemodynamic performance of left ventricular apex, left ventricular free wall, and right ventricular apex pacing in children. METHODS: Studies were performed in 10 children (median age, 2.5 years; range, 2 months to 17 years) undergoing surgery for congenital heart disease with normal systemic left ventricular anatomy and intraventricular conduction. High-fidelity left ventricular and arterial pressure measurements were performed during epicardial right ventricular apex and left ventricular apex and free wall pacing. RESULTS: Left ventricular apex pacing increased the maximum rate of rise of left ventricular pressure and pulse pressure significantly relative to right ventricular apex pacing (by 7.7% +/- 7.2% and 7.7% +/- 7.0%, respectively) without changes in end-diastolic left ventricular pressure. Left ventricular free wall pacing did not significantly improve hemodynamics as compared with right ventricular apex pacing. The QRS duration was not different among pacing at the three sites. CONCLUSIONS: In this short-term study left ventricular apex pacing is hemodynamically superior to right ventricular apex and left ventricular free wall pacing in children. Therefore, the left ventricular apex appears a favorable pacing site after pediatric cardiac surgery.

Adolescent↗
PubMed2005

A Java software for calculating mean breath-by-breath variability in gas exchange parameters: application in young cardiac patients with exercise-related periodic breathing.

Oscillatory changes in parameters of gas exchange have been reported during rest and exercise in cardiac patients with severely depressed left ventricular function. As a result of the growing interest in this oscillatory phenomenon, several methods for assessment of this ventilatory response have been presented in cardiovascular research. Nowadays, objective measurement becomes more important. Therefore, the software reported in this study is based on calculating the mean breath-by-breath variability in respiratory variables and has the advantage that patients can be compared to normal controls. This Java-based software is available for public download under: http://www.perswww.kuleuven.ac.be/Steven_Vangesselen

Belgium↗
PubMed2005

Factors influencing the survival of cryopreserved homografts. The second homograft performs as well as the first.

OBJECTIVE: To determine the life span of cryopreserved homografts implanted in the right ventricular outflow tract and the factors influencing it. METHODS: From 1989 through 2003, we reconstructed the pulmonary valve with 301 homografts in 272 patients (median age 13 years; range 4 days-69 years). Indications were tetralogy of Fallot (136), truncus (23), Rastelli repair (11), double outlet ventricle (13), endocarditis (5), and the Ross operation (84). Median follow-up was 5.7 years (range 0-14). We analyzed possible predictors of graft replacement by simple and multiple Cox regression. RESULTS: Actuarial survival was 96+/-1.2% at 1, 95+/-1.4% at 5, and 94+/-1.5% at 10 years follow-up. Three homografts were explanted because of endocarditis (excluded from the analysis). Freedom from explantation was 99.6+/-0.4% at 1, 94.5+/-1.7% at 5, and 81.8+/-4.1% at 10 years. Variables, significantly related to explantation in the univariate analysis, were younger age, small graft size, implantation in a non-anatomical position, the aortic donor homograft, a shorter aortic cross-clamp time and the implantation of a second homograft. In the multiple model, non-anatomical position (P=0.001), smaller graft size (P<0.0001) or younger age (on square root scale, P<0.0001) and clamp time (P=0.01) remain as independent risk factors. Immunological variables, like blood group incompatibility, implantation of a second homograft and short warm ischemic time were not significant. CONCLUSIONS: The life span of a cryopreserved homograft is determined by graft size (correlates with age) and the non-anatomic position (correlates with indication). In a specific patient, the second homograft performs as well as the first.

Adolescent↗
PubMed2005

Early motor development in young children with 22q.11 deletion syndrome and a conotruncal heart defect.

Velocardiofacial syndrome is identified by a submicroscopic deletion of chromosome 22q.11 (del22q.11). This study presents data on the early motor development and behaviour of 11 children (8 males, 3 females) with del22q.11 (mean age 41mo, SD 9.7mo) with a congenital heart defect. To control for the impact of the congenital heart defect, a control group of 19 children (15 males, 4 females; mean age 46mo, SD 9mo) with the same types of congenital heart defects but without del22q.11 was selected. Motor development in both groups was measured with the Peabody Developmental Motor Scales-2. Behaviour was assessed with the Child Behaviour Checklist. Children with del22q.11 scored significantly lower (p<0.05) on motor performance than the children of the control group. Most deficient motor skills were found for the subtests Locomotion and Stationary. On the behaviour questionnaire, a statistically significant (p<0.05) difference between the two groups was found only for the subscale Withdrawn. These data reveal a significant motor delay in many young children with del22q.11, which is not caused by the presence of a congenital heart defect or by behavioural features.

Case-Control Studies↗
PubMed2005

Validation and application of single breath-hold cine cardiac MR for ventricular function assessment in children with congenital heart disease at rest and during adenosine stress.

PURPOSE: To validate the accuracy of ventricular function analysis using a single breath-hold real-time steady sate free precession (SSFP) cine MR method and demonstrate its application during adenosine stress imaging in children with congenital heart disease. MATERIALS AND METHODS: Twenty-eight subjects with congenital heart disease were studied (mean age 12.4 +/- 2.3 years) with MR imaging at 1.5 T. Short-axis images covering the entirety of both ventricles were acquired at rest, with a conventional segmented SSFP cine sequence acquired over multiple breath-holds and a single breath-hold real-time SSFP sequence. Seventeen subjects were given an infusion of adenosine, and the single breath-hold real-time short-axis stack was repeated during stress. Two independent observers performed the ventricular function analysis. Data was compared between the 2 acquisition methods at rest and between the single breath-hold acquisition at rest and during adenosine stress. RESULTS: There was good agreement between the multiple breath-hold and single breath-hold methods for measurement of end-diastolic volume (r = 0.95 and 0.96, p < .0001) and end-systolic volume (ESV) (r = 0.76 and 0.90, p < .0001) for the left and right ventricles respectively, and the left ventricular mass (r = 0.97, p < .0001). Adenosine was administered safely to all subjects. During stress there were significant changes in the heart rate and ESV, which led to a significant increase in cardiac output (mean 1.5 +/- 1.0 L/min, p < .001). CONCLUSION: Single breath-hold real-time SSFP cine imaging is robust and accurate in assessing cardiac function in children with congenital heart disease. An application of this method is the rapid assessment of cardiac function during adenosine stress.

Adenosine↗
PubMed2005

Physical performance and physical activity in grown-up congenital heart disease.

AIM: To review exercise performance and exercise habits in patients with congenital heart disease (CHD). BACKGROUND AND METHODS: Physical exercise and physical activity has shown beneficial effects on the physical, psychological and social level in adult patients with cardiovascular disease. Favourable effects have also been documented in children with CHD. Exercise testing is preferentially performed on a treadmill in children, with the measurement of gas exchange. RESULTS: An overview of the literature showed that formal exercise testing has frequently documented reduced or suboptimal values for aerobic exercise performance in children with left-to-right shunts (atrial septal defect, ventricular septal defect), valvular heart disease and obstructive anomalies (aortic stenosis, pulmonary stenosis, coarctation of the aorta). Subnormal values for exercise tolerance have also been observed in patients with successfully repaired cyanotic heart disease (tetraology of Fallot, transposition of the great arteries, Fontan operation). An important contributing factor to the impaired exercise performance is the hypoactive lifestyle, as often observed in patients with CHD. This frequently results from parental or environmental overprotection. CONCLUSION: These patients should be stimulated to be physically active, unless medical restriction is imposed. Fortunately, this represents only a small fraction of the total number of congenital heart defects for which sports participation is allowed.

Adult↗
PubMed2004

MR coronary angiography and late-enhancement myocardial MR in children who underwent arterial switch surgery for transposition of great arteries.

PURPOSE: To prospectively evaluate the feasibility of magnetic resonance (MR) coronary artery imaging and to define myocardial damage with late-enhancement myocardial MR imaging in children who underwent arterial switch surgery for transposition of the great arteries. MATERIALS AND METHODS: The local research ethics committee approved this study, and the subjects and/or a parent or guardian gave informed consent. Sixteen asymptomatic subjects who had undergone arterial switch surgery for transposition of the great arteries were studied (mean age, 10.8 years +/- 1.3; 11 male subjects, five female subjects). MR coronary angiography, late-enhancement MR imaging, global ventricular function, and regional wall motion were assessed. Fifteen children were awake during imaging; one was imaged with the use of general anesthetic. RESULTS: In 23 (72%) of 32 coronary arteries imaged, diagnostic-quality images of the coronary ostium and proximal coronary artery course were acquired; this increased to 100% in subjects older than 11 years. No coronary ostial stenoses were seen. In all subjects, the proximal course of the coronary arteries was visualized. Two subendocardial viability defects were detected, which corresponded to known compromise of the artery that supplied that territory at the time of surgery. Global left and right ventricular function were preserved, with no regional wall abnormalities. CONCLUSION: Diagnostic-quality MR coronary angiography is feasible in subjects who have undergone arterial switch surgery for transposition of the great arteries, with no unexpected areas of myocardial infarction detected.

Adolescent↗