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Biomedical subjects

Ute Blanz

Publications and source records attributed to Ute Blanz.

9 recordsLinked to original sources

Endocardial pacing after Fontan-type procedures.

BACKGROUND: Sinus node dysfunction is a frequent complication of Fontan-type procedure. Epicardial pacing is considered as the standard treatment for these patients. METHODS AND RESULTS: We evaluated an endocardial approach in seven patients using a 4.1 French bipolar lumenless lead (SelectSecure) that is positioned through a steerable guiding catheter. Either a purely transvenous or an open transatrial approach can be used for lead placement. The smallest child weighed 12 kg. Individual anatomy was assessed preimplantation using magnetic resonance imaging and injection of radiographic contrast agent through the guiding catheter. A pullback pressure recording was used to confirm unimpaired blood flow into the pulmonary artery. Five of our seven patients underwent de novo transvenous atrial lead implantation for AAIR pacing. In the remaining two patients, both atrial and ventricular leads were inserted. One patient with an intraatrial tunnel underwent transvenous-lead placement. The remaining patient with an extracardiac conduit received atrial and ventricular leads implanted through a guiding catheter inserted through an atriotomy. The postoperative management included short- or long-term oral anticoagulation. CONCLUSIONS: Transvenous endocardial lead implantation avoids the problem of increasing capture thresholds typically observed with epicardial leads. Due to its high tensile strength and lumenless design, the isodiametric lead is expected to remain extractable for an extended period of time.

Adolescent↗

Mechanical ventricular circulatory support in children; Bad Oeynhausen experience.

INTRODUCTION: Recently various mechanical circulatory support systems are being used all over the world, nevertheless the size of the devices limits the implantation in pediatric cases. Accordingly we report our experiences with assist devices applied for pediatric patients. PATIENTS AND METHODS: Twenty-nine children underwent mechanical circulatory support implantation operation. The diagnoses of preoperation were dilated cardiomyopathy in 16, congenital heart disease in 12 and allograft dysfunction in 1. RESULTS: From November 1987 to January 2004 we implanted 7 LVAD, 11 BVAD and 11 ECMO in pediatric patients. The 29 patients were supported from 11 to 231 days (mean 32.3 days). Three children were supported by Thoratec LVAD. Biventricular Thoratec VAD was used in 3 children. Three children were supported by Medos-HIA system LVAD, and 8 children by biventricular VAD using the Medos-HIA system. One child was supported by Novacor LVAD. Fourteen children were supported by ECMO. We succeeded in heart transplantation in 10 cases, but lost 16 children during the support. Bleeding occurred in 7 cases, thrombosis occurred in 6 cases, infection occurred in 8 cases, pneumothorax occurred in 3 cases and neurological deficit occurred in 2 cases. CONCLUSION: The development of assist device for children which has long durability and small in size as a future subject is desired. Further clinical and experimental research and application of those assist devices for children are in progress.

Adolescent↗

Long-term results of pediatric heart transplantation.

OBJECTIVE: We retrospectively reviewed 104 consecutive patients who underwent orthotopic heart transplantation between November 1989 and February 2004. PATIENTS AND METHODS: From November 1989 to February 2004, the total number of heart transplantations were 1,340 cases at our institute. One hundred four (7.8%) of these 1,340 patients were pediatrics. Average age was 6.2 years, ranging from 4 months to 16 years. The cause of heart disease before transplantation was: idiopathic dilated cardiomyopathy (DCM) in 74 patients (71%), and congenital heart disease (CHD) in 30 (29%). RESULTS: Hospital mortality rate was 14.4% (15 patients). Late complications were rejection in 23 (22.1%), infection in 11 (10.6%), gingival hyperplasia in 28 (26.9%), hypertention in 22 (21.1%), coronary artery disease (CAD) in 12 (12.5%), graft failure in 11(10.5%), and malignancy in 2 (1.9%). Late mortality occurred in 11 (10.6%) patients. Causes of death were sudden death in 2 (1.9%), CAD in 3 (2.8%), graft failure in 1 (1.0%), acute rejection in 4 (4.6%), and infection in 1 (1.0%). Actuarial survival rates in pediatrics at 1, 5, 10 years were 82%, 80%, and 78%, respectively. On the other hand, actuarial survival rates in adults at 1, 5, 10 years were 78%, 75%, 59%, respectively. CONCLUSION: Heart transplantation for pediatrics is an effective therapy with acceptable morbidity and mortality. The long-term survival results in pediatrics are comparable to those of adult heart transplantations. However, the actuarial survival rate in pediatrics after 10 years is significantly better than in adults' cases. Renal function in pediatric heart transplantation recipients treated with cyclosporine remains stable during long-term follow-up.

Adult↗

Atrial septal defects in pediatric patients: noninvasive sizing with cardiovascular MR imaging.

PURPOSE: To evaluate phase-contrast magnetic resonance (MR) imaging for sizing of secundum atrial septal defects (ASDs) and inflow MR angiography for detection of associated venous anomalies in pediatric patients with inconclusive transthoracic echocardiographic (TTE) results. MATERIALS AND METHODS: Sixty-five children (mean age, 5.4 years +/- 2.7 [SD]) with ASD and inconclusive TTE results underwent phase-contrast MR imaging. Defect size and rim distances measured on MR imaging sections obtained in the ASD plane and from the defect to the venae cavae, aortic root, and atrioventricular valves were compared with transesophageal echocardiographic (TEE) findings (n = 30) during transcatheter closure or surgical measurements (n = 40) by using Bland-Altman analysis. Inflow MR angiography was compared with invasive cine angiocardiography for detection of associated venous anomalies. RESULTS: For ASD size, mean differences were less than 1 mm between MR imaging and TEE measurements (with upper and lower limits of agreement between 2.3 and -3.3 mm) and were between 1.2 and -1.6 mm between MR imaging and surgical measurements (with upper and lower limits of agreement between 4.7 and -5.2 mm). Septal rim measurements at MR imaging agreed fairly well with TEE and surgical results. Septal length was overestimated at MR imaging versus TEE (mean difference, 3.0 mm; upper and lower limits of agreement, between 8.0 and -2.8 mm), but MR imaging septal length measurements agreed with surgical results. Rim distance to coronary sinus was difficult to assess. MR imaging enabled referral of 25 of 30 patients for successful transcatheter closure; five patients were found to have too large defects after balloon sizing. Multiple ASDs and/or associated vascular anomalies in 17 of 65 patients were clearly identified at MR imaging, compared with results of TEE, surgery, and cardiac catheterization. CONCLUSION: In children with ASD and inconclusive TTE results, MR imaging can enable determination of defect size, rim distances to adjacent structures, and venous connections.

Adolescent↗

Results of staged reconstruction for hypoplasia of the left heart: an experience of 12 years from one institution.

BACKGROUND: We reviewed our 12-year experience with staged reconstruction for hypoplasia of the left heart, examining the results of each surgical step and the impact of the year of the Norwood operation on survival. We compared survival of patients with hypoplasia of the left heart subsequent to completion of the Fontan circulation to survival of patients with a dominant left ventricle undergoing a Fontan procedure. PATIENTS: Between 1989 and 2001, we performed a first stage procedure in 89 patients. Their median age was 9 days, with a range from 2 to 140 days, and the median weight was 3.4 kg, with a range from 2.4 to 5.4 kg. RESULTS: Survival at 1, 4, and 10 years was 55%, 49%, and 49%, respectively. We experienced 23 early deaths (26%), and 12 deaths between the stages of the Norwood cascade. Of our patients, 42 underwent the second stage, and 30 the third stage. Prior to the first stage, symptoms of necrotising enterocolitis, and of obstructed pulmonary venous return, influenced survival significantly. The latter was eliminated as risk factor when surgery was performed within the first week of life. During the later part of our experience, survival at the first stage operation improved significantly, with survival at 3 years increasing from 42% to 75% for the patients at standard-risk (p = 0.017), and from 17% to 42% for those deemed to be at high-risk (p = 0.1). No deaths occurred in 23 patients older than 3 years of age, all of whom had proceeded through the third stage. After completion of the Fontan circulation, the survival of the patients with hypoplasia of the left heart at 4 years was comparable to the survival of patients undergoing the Fontan procedure with a dominant left ventricle (88% versus 90%, p = 0.8). CONCLUSIONS: Early and intermediate survival has improved significantly over the period of 12 years. Late death has been uncommon, and none of our patients are listed for cardiac transplantation.

Cardiac Surgical Procedures↗

Bovine valved venous xenografts for RVOT reconstruction: results after 71 implantations.

BACKGROUND: Pediatric right ventricular outflow tract (RVOT) reconstruction with homo- or porcine xenografts is problematic because of limited availability, lack of material for reconstruction, early degeneration, and tissue ingrowth. Contegra, a bovine jugular vein graft, might be an interesting alternative to overcome these problems. PATIENTS AND METHODS: Within a Federal Drug Administration controlled study, we implanted 71 Contegra pulmonary valved conduits from May 1999 to September 2001 in 71 patients (male/female 33/38) in the age range 2 days-17.4 years, median 1.2 years. Twenty five were primary repairs, 22 had previous graft implantations, and 24 had other repairs/palliations. Preoperative diagnoses: truncus arteriosus communis (19 patients), tetralogy of Fallot (32), double outlet right ventricle (13), transposition of the great arteries (5), and two rare complex malformations. The size of implanted Contegra conduits ranged from 12 to 22 mm. Echocardiography was performed at 1 and 3 months, and then every 3 months postoperatively. Follow-up time was 27 months (maximal), 80 years in total. Results were compared with our 52 homograft- and 30 Tissuemed porcine xenograft recipients. RESULTS: Contegra enables the surgeon to perform all anastomoses without additional material. Its tissue is very apt for suturing and its insufficiencies are common, but without clinical significance or tendency to increase. We saw no sign of conduit or valve degeneration during the whole follow-up up to 27 months. There were no device related adverse events. Redos: five for peripheral pulmonary arteries, two residual ventricular septum defect (VSD) closures. There were six deaths (five early, one late). The maximal transvalvular gradients of 25-42 mmHg were measured in seven patients; these gradients did not increase further during the follow-up. Six patients with completely intact Contegra conduits developed pressure gradients of more than 70 mmHg immediately distal from the conduit. At 27 months, Contegra grafts were advantageous compared to homografts with respect to survival and freedom from explantation. Right ventricle to left ventricle (RV/LV) ratio development and freedom from explantation/redo were equal for Contegra conduits and homografts. Porcine Tissuemed xenografts were significantly inferior. CONCLUSION: The Contegra conduit offers unique tailoring and suturing options for primary and redo RVOT reconstruction. At 27 months, its durability seems at least equivalent to homografts and is superior to porcine Tissuemed xenografts.

Adolescent↗

Acute fulminant myocarditis in children and adolescents: the role of mechanical circulatory assist.

We report children and adolescents in fulminant myocarditis undergoing prolonged circulatory support with different assist devices. Between 1994 and 2004, seven children and adolescents (aged 7-18 years, mean age 13.5 years) were treated with VADs (5 Thoratec, 1 Medos, 1 Novacor) for circulatory support. Three patients underwent left ventricular support; biventricular support was necessary in four patients. Four patients (three left VADs, one bi-VAD) could be successfully bridged to heart transplantation after a mean support time of 163 days (56-258 days). One 7-year-old girl (Medos-BVAD) died after a support time of 11 days because of irreversible multiorgan failure. One 18-year-old patient was successfully weaned from Thoratec BVAD after 66 days with complete recovery of left ventricular function. As good markers, atrial and brain natriuretic peptides were found which reached normal values after recovery of myocardial function. A 15-year-old girl is still on the device. In children or adolescents with irreversible shock in fulminant myocarditis with an anticipated mortality of 100%, both successful bridging to heart transplantation and successful bridging to recovery are possible. Young patients with fulminant myocarditis should be rapidly transferred to a clinic with a mechanical circulatory support program to offer this life-saving option.

Acute Disease↗

Introduction of a new oxygenator including a tight fiber for long-term ECMO in infants.

Plasma leakage is a known complication in the use of a microporous membrane oxygenator in extracorporeal membrane oxygenation cases. An oxygenator with a tight fiber offers an alternative whereby plasma leakage can be prevented. We report the use of such an oxygenator in 13 extracorporeal membrane oxygenation cases in which no problems were encountered regarding blood trauma and plasma leakage.

Equipment Design↗