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Biomedical subjects

M G Hazekamp

Publications and source records attributed to M G Hazekamp.

At least 19 recordsLinked to original sources
PubMed2006

[Favourable results with surgical treatment in 43 children with hypoplastic left-heart syndrome or similar disorders, 1999-2005].

OBJECTIVE: To describe the results of surgical treatment of hypoplastic left-heart syndrome (HLHS) and HLHS-like disorders in the Amsterdam-Leiden Centre for Congenital Heart Disease, the Netherlands. DESIGN: Retrospective, descriptive. METHOD: Data were collected on 43 neonates with HLHS or similar disorders who underwent surgical treatment between December 1999 and December 2005. HLHS was present in 37 patients and 6 had disorders similar to HLHS (unbalanced atrioventricular septal defect, truncus arteriosus with hypoplastic left ventricle, double inlet left ventricle). Surgery was performed in 3 steps: Norwood operation shortly after birth (n = 43), bidirectional cavopulmonary anastomosis a few months later (n = 30) and total cavopulmonary connection at the age of 2-3 years (n = 10). During the Norwood operation, the first 21 patients received a modified Blalock shunt (between the right brachiocephalic artery and pulmonary artery), whereas the following 22 patients received a Sano shunt (between the right ventricle and pulmonary artery). RESULTS: Of the 43 patients, 11 died: 7 within 30 days of the first operation, 2 between the first and second operation, and 2 between the second and third operation. Actuarial survival for the entire group is 74% (32/43). The mortality rate was lower with the Sano shunt (9%; 2/22) than with the modified Blalock shunt (43%; 9/21). Catheter interventions were necessary in 10 patients: 6 had balloon dilatation of the distal aortic arch and 4 had balloon dilatation/stent placement for narrowed pulmonary arteries. With a median follow-up of 22 months (range: 1-75), 2 patients had marked neurological side effects. All 32 surviving patients were in good clinical condition.

Child, Preschool↗
PubMed2006

Surgical repair of aortopulmonary window: thirty-seven years of experience.

An aortopulmonary window (APW) is a communication between the ascending aorta and the pulmonary trunk in the presence of two separate semilunar valves. In order to increase our understanding about the surgical management of this rare lesion and its long-term results, we describe our experience over a 37-year period. Between 1968 and 2005, 18 patients were diagnosed with APW. Seventeen underwent surgical correction. Age at operation ranged from 22 days to 22 years (median, 0.20 years). Follow-up ranged from 2 weeks to 28.6 years (median, 11.0 years). Surgical closure was achieved using a single patch in 7 patients (41.2%) double patch in 4 (23.5%), primary closure in 3 (17.6%), clip in 2 (11.8%), and ligation in 1 (5.9%). Complex APW was present in 8 patients (44.4%). One patient was treated nonsurgically. There were no early or late deaths after surgery. Both primary closure and patch closure gave excellent long-term results. Sporadic postoperative complications were only associated with complex lesions. One patient who was treated conservatively died (of pulmonary hypertension) 21 years after diagnosis. Repair of APW is ideally performed in the first months of life, before irreversible PHT has developed. Various surgical repair techniques in this series of patients gave excellent short-term and long-term results, without significant hemodynamic sequelae.

Adolescent↗
PubMed2006

[Mechanical circulatory support after paediatric cardiac surgery].

When circulatory failure occurs after paediatric cardiac surgery despite conventional therapy (inotropic medication, optimising pre- and afterload) mechanical assist devices can be used. Assist devices can be categorised in different ways: according to the type of pump used (centrifugal, axial flow, or pneumatic), according to univentricular or biventricular support and in relation to the presence of an oxygenator. Paediatric devices are non-implantable. Extra-corporeal membrane oxygenation (ECMO) consists of a roller pump and a membrane oxygenator and is a relatively simple means of biventricular cardiac support while respiratory support is provided at the same time. All other devices lack the oxygenator and thus provide only circulatory support. The main disadvantage of ECMO is that it can be used for a maximum of several weeks while modern pneumatic assist devices (MEDOS, Berlin Heart) can be used for several months. Thromboembolic events, bleeding and sepsis are the main complications of all assist devices. The use of circulatory assist devices can increase the chances of survival when severe cardio(pulmonary) failure occurs following surgical correction of congenital heart defects.

Cardiac Surgical Procedures↗
PubMed2005

Effect of three different anaesthetic agents on the postoperative production of cardiac troponin T in paediatric cardiac surgery.

BACKGROUND: Paediatric cardiac surgery is associated with some degree of myocardial injury. Ischaemic preconditioning (IP) has been investigated widely in the adult population. Volatile agents have been shown to simulate IP providing extra protection to the myocardium during adult cardiopulmonary bypass (CPB) while propofol seems to act through different mechanisms. IP has not been investigated in the paediatric population to the same extent. Cardiac troponin T (cTnT) is a reliable marker of myocardial injury in neonates and children. We have investigated the relationship between three anaesthetic agents, midazolam, propofol, and sevoflurane, and postoperative production of cTnT. METHODS: Ninety patients undergoing repair of congenital heart defect with CPB were investigated in a prospective randomized study. cTnT was measured four times during the first 24 h following admission to the paediatric intensive care unit. Other variables measured included arterial blood gases, lactate, fluid balance, use of inotropic drugs, PaO2/FiO2 ratio and ventilator hours. RESULTS: cTnT was elevated in all three groups throughout the study period. The differences between the three groups were not statistically significant. Eight hours after admission to the intensive care unit cTnT concentrations tended to be higher in the midazolam group [mean (95% confidence intervals)]; 2.7 (1.9-3.5) ng ml(-1). Patients receiving a propofol-based anaesthesia had similar concentrations 2.6 (1.7-3.5) ng ml(-1) while those receiving sevoflurane tended to have a lower cTnT production 1.7 (1.3-2.2) ng ml(-1). CONCLUSIONS: Midazolam, propofol, and sevoflurane appear to provide equal myocardial protection in paediatric cardiac surgery when using cTnT as a marker of myocardial damage.

Anesthetics, Inhalation↗
PubMed2005

[Complete atrioventricular septal defect in children with Down's syndrome: good results of surgical correction at younger and younger ages].

OBJECTIVE: To evaluate the results of cardiosurgical treatment of children with Down's syndrome and a complete atrioventricular septal defect (cAVSD). DESIGN: Retrospective. METHOD: Data were collected from the records of all patients with Down's syndrome who had been subjected to primary corrective surgery for cAVSD in the period 1980-2003 in Leiden, The Netherlands. Exclusion criteria were: concomitant tetralogy of Fallot or interruption of the aortic arch and palliative banding of the pulmonary artery. Children with an abnormal shape of the ventricle making it impossible to correct biventricularly were not considered in the study. Data on mortality >30 days after the operation and on repeated surgery were included in the analysis if the duration of follow-up was at least 5 years. RESULTS: The group comprised 148 children: 75 girls and 73 boys. The median age at time of surgery was 20 weeks (range: 6 weeks to 3.7 years) and showed a statistically significant decrease during the period under investigation. Of 4 children lost to clinical follow-up actual data could be obtained. The median duration offollow-up was 6 years and 7 months (range: 38 days to 23 years and 11 months). 28 children (19%) died. The mortality within 30 days after the operation decreased from 0-38% in the period 1980-1989 via 0-30% in the period 1990-1999 to 0% in 2000-2003. The percentage ofreoperations related to the correction ofcAVSD (14%; 14/98) did not seem to increase. Of the correction-related reoperations, 14% (2/14) were followed by a second reoperation. Conclusion. In the period 1980-2003, children with Down's syndrome and a cAVSD were corrected surgically at a younger and younger age. The early mortality decreased to 0% in the years 2000-2003. Echocardiography in the first weeks of life for all children with Down's syndrome makes it possible to diagnose those with a cAVSD early enough for surgical repair.

Age Factors↗
PubMed2005

An unexpected cause of a recurrent cerebral hemorrhage.

A 4-year-old previously healthy boy presented with a non-traumatic right parietal hemorrhage. A second life-threatening left cerebral hemorrhage occurred three weeks later and was decompressed with a craniotomy. Transthoracic echocardiography revealed a hypermobile elongated tumor of the mitral valve. The cardiac tumor was successfully resected three weeks after the craniotomy. Histological examination of the cardiac tumor revealed a papillary lesion of spindle cells with smooth muscle cell differentiation. In view of the histological findings and the clinical symptoms, a cellular myofibroblastic tumor was considered the most likely diagnosis in our patient. Although a cardiac tumor is a rare cause of a cerebral hemorrhage, a cardiac evaluation is recommended in pediatric patients with a cerebral hemorrhage of unknown etiology.

Cerebral Hemorrhage↗
PubMed2004

Gut permeability in paediatric cardiac surgery.

BACKGROUND: Intestinal mucosal ischaemia can occur in infants and children during and after cardiac surgery. Severe decreases in mucosal perfusion may cause complications such as necrotizing enterocolitis and postoperative mortality. We investigated gut permeability in paediatric patients undergoing cardiac surgery using the dual sugar permeability test and absorption of two other saccharides. METHODS: Thirty-four patients undergoing palliative or corrective surgical procedures with and without cardiopulmonary bypass were investigated. Intestinal permeability was measured using 3-O-methyl-D-glucose, D-xylose, L-rhamnose and lactulose, given orally after induction of anaesthesia and 12 and 24 h later. RESULTS: Lactulose/rhamnose ratios were raised from the outset [median 0.39 (confidence interval 0.07-1.8 for patients undergoing operations without cardiopulmonary bypass and 0.30 (0.02-2.6) with cardiopulmonary bypass]. The highest lactulose/rhamnose ratios were recorded 12 h after surgery 0.32 (0.07-6.9), when cardiopulmonary bypass was used. This is approximately seven times the value expected in healthy children. There was an improvement in patients not undergoing cardiopulmonary bypass: 0.22 (0.03-0.85) 12 h and 0.11 (0-0.48) 24 h after induction of anaesthesia. Patients undergoing repair of aortic coarctation showed the fastest recovery: 0.09 (0.03-0.31) 12 h and 0.07 (0.04-0.35) 24 h after induction of anaesthesia. CONCLUSIONS: Patients with congenital heart defects have abnormal gut permeability when compared with healthy children of similar age. Cardiopulmonary bypass seems to affect the intestinal barrier morphologically (lactulose and rhamnose absorption) and functionally (3-O-methyl-D-glucose and D-xylose absorption).

Cardiopulmonary Bypass↗
PubMed2003

Decellularization of rat aortic valve allografts reduces leaflet destruction and extracellular matrix remodeling.

OBJECTIVES: Decellularization of aortic valve allografts in advance of transplantation is a promising approach to overcome immune-induced early graft failure. In this study the effects of in vitro cell extraction on extracellular matrix molecules and in vivo remodeling of decellularized aortic valves were investigated in a heterotopic aortic valve rat implantation model. METHODS: Rat aortic valve conduits were decellularized by a 2-step detergent-enzymatic extraction method involving sodium dodecyl sulfate in combination with RNase and DNase. Cellular and acellular allogeneic (2x, n = 4) and syngeneic valve grafts (2x, n = 3) were grafted infrarenally into the descending aorta for 21 days. Immunohistochemical techniques were used to study extracellular matrix constitution (elastin, collagen, fibronectin, and chondroitin sulfate) and cellular infiltration. RESULTS: The decellularization procedure resulted in a complete loss of all cellular structures from the entire valve conduit with minimal damage to the extracellular matrix. All transplanted cellular allografts became deformed, swollen, and acellular with major changes in extracellular matrix structure. The transplanted decellularized allografts, however, retained normal preserved valve leaflets comparable to transplanted cellular and acellular syngeneic grafts. With the exception of cellular syngeneic grafts, all other grafts showed retrovalvular thrombi. CONCLUSIONS: Damage to the valves caused by decellularization technique is much less than the damage caused by the recipient's immune response. In vitro removal of viable cells in (cryopreserved) homografts may decrease graft failure. Seeding with autologous or major histocompatibility complex-matched donor endothelial cells will be necessary to diminish damage induced by an absent blood-tissue barrier.

Animals↗
PubMed2002

Report of the Dutch experience with the Ross procedure in 343 patients.

OBJECTIVE: Limited information is available on outcome after autograft aortic valve replacement, in particular with respect to the durability of the autograft and of the allograft used to reconstruct the right ventricular outflow tract. A retrospective follow-up study of all patients who underwent a Ross procedure in the Netherlands since 1988 was done to obtain an overview of the Dutch experience with this procedure. METHODS: From 1988 to January 2000, 348 Ross procedures were performed in nine centers in the Netherlands. Pre-operative, peri-operative and follow-up data from 343 patients in seven centers (99% of all Dutch autograft patients) were collected and analyzed. RESULTS: Mean patient age was 26 years (SD 14, range 0-58) and male/female ratio was 2.1. Bicuspid valve or other congenital heart valve disease was the most common indication for operation. The root replacement technique was used in 95% of patients and concomitant procedures were done in 12%. Hospital mortality was 2.6% (N=9). Mean follow-up was 4 years (median 3.8, SD 2.8, range 0-12.5). Overall cumulative survival was 96% at 1 year (95% confidence interval (CI) 94-98%) and 94% at 5 and 7 post-operative years, respectively (95% CI 91-97%). At last follow-up, 87% of the surviving patients was in New York Heart Association (NYHA) class I. Independent predictors of overall mortality were pre-operative NYHA class IV/V and longer perfusion time. Autograft reoperation had to be performed in 14 patients and reintervention on the pulmonary allograft in 10 patients. Freedom from any valve-related reintervention was 88% at 7 years (95% CI 81-94%). CONCLUSIONS: The Dutch experience with the Ross procedure is favorable, with low operative mortality and good mid-term results. Although both the autograft in aortic position and the allograft in the right ventricular outflow tract have a limited durability, this has not yet resulted in considerable reoperation rates and associated morbidity and mortality.

Adolescent↗
PubMed2002

ECG predictors of ventricular arrhythmias and biventricular size and wall mass in tetralogy of Fallot with pulmonary regurgitation.

BACKGROUND: In patients with the tetralogy of Fallot, QRS prolongation predicts malignant ventricular arrhythmias. QRS prolongation may result from right ventricular dilatation. The relation of ECG markers to biventricular wall mass and volumes has not been assessed. OBJECTIVE: To investigate the relations of surface ECG markers of depolarisation and repolarisation to right and left ventricular volume and biventricular wall mass. METHODS: 37 Fallot patients (mean (SD) age 17 (9) years) were studied 14 (8) years after surgical repair; 34 had important pulmonary regurgitation. Left and right ventricular size was assessed from tomographic magnetic resonance imaging (MRI), and the amount of pulmonary regurgitation by velocity mapping MRI. QT, QRS, and JT duration and interlead dispersion markers were derived from a standard 12 lead ECG. RESULTS: Mean QRS duration was significantly prolonged (133 (31) v 91 (11) ms in controls), as were dispersion of QRS (36 (17) v 20 (6) ms), QT interval (87 (48) v 42 (20) ms), and JT interval (93 (48) v 42 (19) ms). Biventricular volumes were increased (right ventricular end diastolic volume, 129 (41) v 70 (9) ml/m(2); left ventricular end diastolic volume, 83 (16) v 69 (10) ml/m(2)), as was right ventricular wall mass (24 (7) v 17 (2) g/m(2)). QRS duration correlated best with right ventricular mass (r = 0.55, p < 0.01). CONCLUSIONS: In patients operated on for tetralogy of Fallot and with pulmonary regurgitation, ECG predictors of ventricular arrhythmias are influenced by several mechanical factors that may occur simultaneously. These include increased right ventricular volume, but also increases in left ventricular volume and in right and left ventricular wall mass.

Adolescent↗
PubMed2001

Implantation of cardioverter device in young children: the perirenal approach.

Placement of Implantable cardioverter devices in young children is complicated because of the relatively large size and heavy weight of these devices. A technique is described where the device is implanted in the left perirenal space while an endovascular lead is used instead of an epicardial patch electrode.

Age Factors↗
PubMed2001

Outcome and follow-up of aortic valve replacement with the freestyle stentless bioprosthesis.

BACKGROUND: The aim of this study was to determine the morbidity, mortality, and hemodynamics after implantation of the Freestyle stentless bioprosthesis in the aortic position. METHODS: A total of 280 patients were operated on from June 1993 to July 1999 as part of a multicenter investigation. Factors influencing hospital mortality and long-term survival were assessed by logistic regression and Cox proportional hazards analysis. Patients were evaluated postoperatively at discharge, at 3 to 6 months, and yearly by clinical examination and color flow Doppler echocardiography. RESULTS: Hospital mortality in this group was relatively high (9.6%). Logistic regression analysis showed that cross-clamp time, age, myocardial infarction, diabetes, left ventricular hypertrophy, coronary artery disease, New York Heart Association class III or IV and female gender were the independent predictive factors. According to the Kaplan-Meier method, the 4-year survival for hospital survivors was 94%. In the multivariate Cox proportional hazard analysis, only coronary artery disease proved to be prognostic. During follow-up, 11 patients developed paravalvular leakage due to prosthetic dehiscence at the side of the noncoronary cusp. Performance of the prosthesis as assessed by echocardiography was excellent. Mean gradient decreased significantly between discharge and follow-up at 3 to 6 months. At 1-year follow-up trivial regurgitation was found in 6 patients (3%) and mild regurgitation in 4 (2%). Regurgitation did not increase with time. The effective orifice area increased significantly from discharge to follow-up at 3 to 6 months. CONCLUSIONS: Hospital mortality after implantation of a stentless bioprosthesis was higher compared to conventional prosthesis. A high incidence of prosthesis dehiscence at the proximal suture line was found, which was probably due to technique. Hemodynamic performance up to 3 years showed low transvalvular gradients. There is echocardiographic evidence for reduction of left ventricular hypertrophy and improvement of left ventricular function.

Actuarial Analysis↗
PubMed2001

Pulmonary valve insertion late after repair of Fallot's tetralogy.

OBJECTIVES: To analyze the results of pulmonary valve insertion late after initial repair of Fallot's tetralogy. Pulmonary insufficiency (PI) after correction of Fallot's tetralogy is usually well tolerated in the short term, but is associated with symptomatic right ventricular dilatation and an increased risk of ventricular arrhythmias over longer periods of time. METHODS: From 1993 to July 2000, 51 patients were reoperated for PI at a mean age of 25.7+/-11.9 years. The mean age at initial repair was 6.4+/-7.2 years. Patients with a conduit inserted at initial operation, with absent pulmonary valve syndrome or with a more than moderate ventricular septal defect at reoperation were excluded from the study. A cryopreserved pulmonary (96%) or aortic (4%) homograft was implanted in the orthotopic position with the use of cardiopulmonary bypass 19.3+/-9.1 years (2.7-40.3 years) after initial correction. Preoperative symptoms (New York Heart Association, NYHA class), degree of PI (echo-Doppler, MRI), right ventricular dimensions (MRI) and QRS duration were compared to findings at last follow-up. RESULTS: Follow-up is complete and had a mean duration of 1.7+/-1.4 years. Hospital mortality was 2%. No serious morbidity occurred. Severe PI was present preoperatively in all patients. At last follow-up echo-Doppler studies showed PI to be absent or trivial in 96% and mild in 4% of patients. In 13 patients MRI studies were performed both pre- and postoperatively: in this group PI was reduced from a mean of 48 to 4%. After 6 months NYHA capacity class had improved significantly from 2.3+/-0.6 to 1.4+/-0.5. After 1 year end-diastolic and end-systolic right ventricular volumes were reduced significantly. Right ventricular ejection fraction and QRS duration remained unchanged. CONCLUSIONS: PI late after correction of Fallot's tetralogy may lead to serious symptomatic right ventricle dilatation. After pulmonary homograft insertion right ventricular dimensions decrease rapidly and functional improvement is observed in almost all patients.

Adult↗
PubMed2001

Prime solutions for cardiopulmonary bypass in neonates: antioxidant capacity of prime based on albumin or fresh frozen plasma.

OBJECTIVE: Oxidative damage and inflammation are believed to play an important role in postoperative complications after cardiopulmonary bypass. During bypass, a prime solution with a high antioxidant capacity may reduce the oxidative damage and inflammation. We investigated total antioxidant capacity and individual scavengers during the preparation of 2 different prime solutions. METHODS: The prime solutions were prepared with either pasteurized human albumin or fresh frozen plasma. The total antioxidant capacity was measured with the total radical antioxidant parameter assay and with the ferric-reducing ability of plasma assay. The individual scavengers vitamin C, sulfhydryl groups, uric acid, and total protein were measured before, during, and after the prime preparation. Malondialdehyde was measured as a parameter for lipid peroxidation. RESULTS: Neither prime solution showed a total radical antioxidant parameter value. The ferric-reducing ability of plasma value of prime solutions was lower than that of undiluted human albumin or fresh frozen plasma. Addition of mannitol did not increase the ferric-reducing ability of plasma value. Vitamin C was only found in the fresh frozen plasma prime. Both prime solutions contained sulfhydryl groups and uric acid in low concentrations. During ultrafiltration, low-molecular-weight antioxidants were lost into the ultrafiltrate. CONCLUSIONS: We showed that prime solutions based on either albumin or fresh frozen plasma had very low antioxidant capacity and that ultrafiltration of the prime solution further lowers this capacity. A prime solution with a low antioxidant capacity may increase oxidative stress in neonates undergoing cardiopulmonary bypass.

Albumins↗
PubMed2001

Aortic valve replacement in patients with aortic valve stenosis improves myocardial metabolism and diastolic function.

PURPOSE: To evaluate whether functional and metabolic changes recover after aortic valve replacement (AVR). MATERIALS AND METHODS: Eighteen men with aortic valve stenosis (mean pressure gradient +/- SD, 79.9 mm Hg +/- 15.1) underwent magnetic resonance (MR) imaging and phosphorus 31 MR spectroscopy. In nine patients who underwent AVR, MR imaging and spectroscopy were repeated 40 weeks +/- 12 after AVR. Ten age-matched healthy men were control subjects. RESULTS: Before AVR, the myocardial phosphocreatine (PCr)-to-adenosine triphosphate (ATP) ratio in the 18 patients was 1.24 +/- 0.17 and 1.43 +/- 0.14 in the control group (P <.01). In nine patients who underwent follow-up MR spectroscopy, the ratio increased from 1.28 +/- 0.17 to 1.47 +/- 0.14 (P <.05) following AVR. Before AVR, early acceleration peak corrected for cardiac output was (0.043 +/- 0.008) x 10(-3) sec(-1) in patients and (0.081 +/- 0.033) x 10(-3) sec(-1) in the control group (P <.05). After 40 weeks +/- 12, the mean early acceleration peak corrected for cardiac output in the nine patients increased significantly to (0.055 +/- 0.006) x 10(-3) sec(-1) (P <.05), although it was still significantly lower than that of the control group (P <.05). Before AVR, a significant correlation was found between the myocardial PCr-ATP ratio and left ventricular diastolic function (n = 18; P <.05). CONCLUSION: Severe aortic valve stenosis leads to a decreased myocardial PCr-ATP ratio and impairment of left ventricular diastolic function; following AVR, the ratio normalizes completely, whereas function improves significantly. There is an association between altered myocardial high-energy phosphate metabolism and impaired left ventricular diastolic function.

Adenosine Triphosphate↗