Papers by Oliver Kretschmar
Journal of interventional cardiology, 2015
To assess feasibility, safety and effectiveness of right ventricular outflow tract (RVOT) stentin... more To assess feasibility, safety and effectiveness of right ventricular outflow tract (RVOT) stenting in symptomatic young infants. Multicentre evaluation of 35 patients intended to undergo RVOT stenting in 11 pediatric cardiac centres from 2009 to August 2011. Median age and weight at the time of first stent implantation were 8 weeks and 3.3 kg, with 40% of patients <3 kg. A total of 19 patients had suffered from hypoxemic spells, 8 patients were ventilated, 6 on inotropic support and 5 on prostaglandin infusion. Severe concomitant malformations were present in 11 patients, and acute infections in 2. Stenting of the RVOT was successfully performed in 33 patients, improving oxygen saturation from a median of 77 to 90% 2 days after intervention. Besides the 2 patients in whom RVOT stenting was not successful for technical reasons, there were no procedural complications. In 17 of 33 patients, 1-3 reinterventions were performed during follow-up, less than half of those were reintervent...
Journal of thoracic disease, 2015
Pediatric heart transplantation (pHTx) represents a small (14%) but very important and particular... more Pediatric heart transplantation (pHTx) represents a small (14%) but very important and particular part in the field of cardiac transplantation. This treatment has lifelong impact on children. To achieve the best short and especially long-term survival with adequate quality of life, which is of crucial importance for this young patient population, one has to realize and understand the differences with adult HTx. Indication for transplantation, waitlist management including ABO incompatible (ABOi) transplantation and immunosuppression differ. Although young transplant recipients are ultimately likely to be considered for re-transplantation. One has to distinguish between myopathy and complex congenital heart disease (CHD). The differences in anatomy and physiology make the surgical procedure much more complex and create unique challenges. These recipients need a well-organized and educated team with pediatric cardiologists and intensivists, including a high skilled surgeon, which is d...
European Journal of Cardio-thoracic Surgery, 2011
Results. A total of 50 patients with a median (range) age of 7.5 (0.5-16.5) yr were enrolled in t... more Results. A total of 50 patients with a median (range) age of 7.5 (0.5-16.5) yr were enrolled in the study. Mean CO values were 3.7 (1.5) litre min21 (PAC thermodilution) and 3.1 (1.7) litre min21 (Aesculonw monitor). Analysis for CO measurement showed a good correlation between the two methods (r¼0.894; P,0.0001). The bias between the two methods was 0.66 litre
Pediatrics, 2014
This report describes an 8-year-old child with acute anthracycline-induced cardiomyopathy trigger... more This report describes an 8-year-old child with acute anthracycline-induced cardiomyopathy triggered by human herpesvirus 6 and the subsequent implantation of an intracorporeal continuous-flow left ventricular assist device (LVAD) and the process to discharge the child from the hospital. After barely 3 months on mechanical support, the device was explanted after thorough examination. Experiences regarding LVAD removal are limited, and no guidelines for echocardiographic and hemodynamic criteria for LVAD removal in children have been published thus far. We present our institutional algorithm for device selection, surveillance in an ambulatory setting, and testing for myocardial recovery, as well as our criteria for LVAD explantation in children.
European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery, Jan 11, 2014
Children suffering from left atrioventricular valve (LAVV) disease not amenable to repair represe... more Children suffering from left atrioventricular valve (LAVV) disease not amenable to repair represent a significant challenge. The results of surgical reconstruction are not optimal. Valve replacement as an alternative is associated with poor results. The surgical-hybrid approach with implantation of a stented biological valve (bovine jugular vein graft, Melody® valve) seems to represent a new therapeutic option. Here we demonstrate our case, the consideration and the approach to extreme clinical findings in a small child. We describe a simplified surgical-hybrid Melody valve implantation in a LAVV position. The technique of implantation is relatively simple and the immediate postoperative result very good.
The Pediatric Infectious Disease Journal, 2008
Congenital heart disease (CHD) is a risk factor for infective endocarditis (IE). We aimed to asse... more Congenital heart disease (CHD) is a risk factor for infective endocarditis (IE). We aimed to assess the impact of cardiac interventions on the frequency and microbial profile of IE in children with CHD. Episodes of IE were analyzed in children aged &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; or =18 years with CHD between 1995 and 2005 with respect to cardiac surgery or catheter interventions with or without implantation of foreign material. Diagnosis of IE was made in 14 (0.36%) of 3826 children with CHD including native IE in 6 and postinterventional IE in 8 patients. During the period 3029 cardiac interventions (1944 surgeries; 1085 catheters) were performed; foreign material was implanted in 1360 interventions (1139 surgeries; 221 catheters) including all 8 patients with postinterventional IE. Cardiac intervention by itself did not change the risk for IE compared with no intervention. The risk of IE after implantation of foreign material was higher than following intervention without implantation (odds ratio, 21.0; 95% confidence interval, 1.2-365; P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). Pacemaker implantation was associated with the highest risk for IE (odds ratio, 11.0; 95% confidence interval, 2.6-46.5; P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). Staphylococci were the most frequently isolated organisms in foreign material-associated IE. Cardiac intervention in children with CHD does not increase the risk for IE. Postinterventional IE in children with CHD is strongly linked to implantation of foreign material, especially of pacemaker.
Pediatric Cardiology, 2008
The global myocardial function in patients after repair of tetralogy of Fallot (TOF) can be asses... more The global myocardial function in patients after repair of tetralogy of Fallot (TOF) can be assessed by cardiovascular magnetic resonance (CMR) and measurement of B-type natriuretic peptides. Two-dimensional echocardiography-derived strain and strain rate (2D strain) facilitate the assessment of regional myocardial function. We evaluated myocardial function in 16 children with residual severe pulmonary valve regurgitation and right ventricular (RV) volume overload after TOF repair before, 1 month after, and 6 months after pulmonary valve replacement (PVR). In 2D strain echocardiography preoperatively, the longitudinal systolic RV strain was reduced (p \ 0.05). One month after PVR, longitudinal systolic RV strain decreased further (p \ 0.05), while systolic and early diastolic radial left ventricular strain and strain rate increased (each p \ 0.05), followed by a return toward preoperative values after 6 months. Six months after PVR, preoperatively elevated RV end-diastolic volume (p \ 0.01) assessed by CMR and N-terminal pro-B-type natriuretic peptide (p \ 0.05) decreased. In conclusion, the impairment of the regional myocardial after TOF repair and transient changes after PVR can be subtly analyzed by 2D strain echocardiography in addition to the established assessment of myocardial function with CMR and measurement of B-type natriuretic peptides.
Pediatric Cardiology, 2008
Our objective was to compare calculated (LaFarge) with measured oxygen consumption (VO 2 ) using ... more Our objective was to compare calculated (LaFarge) with measured oxygen consumption (VO 2 ) using the AS/3 TM Compact Airway Module M-CAiOVX (Datex-Ohmeda, Helsinki, Finland; AS/3 TM) in children without cardiac shunts in a prospective, observational study. VO 2 was determined at the end of the routine diagnostic and/or interventional catheterization. VO 2 was calculated according to the formula of LaFarge and Miettinen for each child and compared with the measured VO 2 . Data were compared using simple regression and Bland Altman analysis. Fiftytwo children aged from 0.5 to 16 years (median, 6.9 years) and weighing 3.4 to 59.4 kg (median, 22.9 kg) were investigated. Calculated VO 2 values ranged from 59.0 to 230.8 ml/min, and measured VO 2 values from 62.7 to 282.2 ml/min. Comparison of calculated versus measured VO 2 values revealed a significant correlation (r = 0.90, p \ 0.0001). Bias and precision were 8.9 and 48.3 ml/min, respectively (95% limits of agreement: -39.4 to 57.2 ml/ min). Comparison of calculated VO 2 in children older than 3 years (n = 41), as restricted to the formula, with measured VO 2 , revealed a slightly reduced correlation (r = 0.86, p \ 0.0001). Bias and precision were 10.0 and 52.5 ml/min, respectively (95% limits of agreement: -42.4 to 62.5 ml/ min). We conclude that calculation of VO 2 by the LaFarge formula does not provide reliable values compared to measured values. In clinical routine, measured rather than calculated VO 2 values should be used for the estimation of cardiac output and related variables.
The Journal of Pediatrics, 2009
Journal of Pediatric Hematology/Oncology, 2005
Thrombolytic therapy is a well-defined treatment option for arterial and venous thrombosis in adu... more Thrombolytic therapy is a well-defined treatment option for arterial and venous thrombosis in adults. In contrast, uniform recommendations regarding the indication, route of administration, and dosing of thrombolytic therapy in children are not available. The authors report the successful resolution of bilateral pulmonary embolism and popliteal artery thrombosis in an 11-year-old girl and 13-year-old girl, respectively, by catheter-directed thrombolysis with low-dose recombinant tissue plasminogen activator. Catheter-directed low-dose thrombolysis is an efficient treatment option for severe venous and arterial thrombosis in children.
The International Journal of Cardiovascular Imaging, 2005
Objectives: The scope of the study was to evaluate a recent software for angiographic volume dete... more Objectives: The scope of the study was to evaluate a recent software for angiographic volume determination as compared to cardiovascular magnetic resonance imaging. Background: A new right ventricular analysis software closes a diagnostic gap in quantitative angiography. Cardiovascular magnetic resonance imaging short axis multi slice summation is a validated reference standard. Methods: Right ventricular angiograms were acquired in frontal and lateral projection in 15 pediatric and 17 adult patients. Additional angiograms were acquired in RAO30°/LAO60°projections in 10 adult patients. The tested models comprised area length with different regressions, multi-slice with different regressions, Boak, and pyramid method. Original regressions were used to calculate angiographic right ventricular volume. Right ventricular reference volumes were determined by multi-slice summation from cardiac magnetic resonance short-axis images. Results: Mean inter-observer difference was )1 ml (95% confidence: )35-34 ml) and mean intra-observer difference was 0 ml (95% confidence: )22-22 ml). There was no significant difference (4 ml, 95% confidence: )22-30 ml) between geometric calibration and calibration by a sphere. The area length and multi-slice models demonstrated the best agreement with the cardiac magnetic resonance reference. Performance was best for the Onnasch Lange models. Conclusion: The evaluated software provides acceptably accurate volume estimates for the majority of ventricles. In a few cases larger errors may occur, however. The area length and multi-slice models preferably with Onnasch Lange regressions may be recommended. Inter-and intraobserver agreement were excellent. Geometric calibration using data from DICOM header files may be used.
International Journal of Cardiology, 2011
Rare combination of congenital aplasia of the right pulmonary veins, left ventricular noncompacti... more Rare combination of congenital aplasia of the right pulmonary veins, left ventricular noncompaction, partial membranous obstruction of left-sided pulmonary veins and secundum atrial septal defect
International Journal of Cardiology, 2011
Corresponding author at: University Children&#x27;s Hospital, Division of Pediatric Cardiolog... more Corresponding author at: University Children&#x27;s Hospital, Division of Pediatric Cardiology, Steinwiesstrasse 75, CH 8032 Zurich, Switzerland. Tel.: + 41 44 266 76 17; fax: + 41 44 266 79 81. ... Received 9 June 2011; accepted 11 July 2011. published online 02 August 2011.
International Journal of Cardiology, 2010
Background: To report usability, safety, and efficacy of the self-centering Solysafe Septal Occlu... more Background: To report usability, safety, and efficacy of the self-centering Solysafe Septal Occluder for transcatheter closure of secundum type atrial septal defect (ASD) in paediatric patients. Methods: Retrospective observational clinical study in two tertiary care centers for congenital heart diseases. Patients: First 37 (median age 8.7 years, 68% female) consecutive patients with an ASD stretched diameter up to 22 mm in whom a Solysafe Septal Occluder was used to close a haemodynamically significant ASD. Interventions: Transcatheter closure of ASD was performed under general anaesthesia with trans-esophageal echo guidance. Stretched diameter of the ASD was assessed by balloon sizing. Main outcome measures: Rate of success, complete closure rate, and complications (defined as vascular complications, device-related complications such as embolism, thrombus formation, device erosions, infections, and arrhythmia) during follow up. Results: 37 procedures were performed, success rate was 87% (32 of 37 pts.). A missing retroaortic rim was the main reason for device failure. Complete ASD closure rate was 78% immediately in cath lab (25 of 32 pts.), 90% after four weeks (28 of 31 pts.), 94% after three months (29 of 31 pts.), and 100% after six months (20 of 20 pts.). Procedure-related complication was femoral vein thrombosis in one patient. Conclusions: The Solysafe Septal Occluder is a feasible, safe, and clinically efficient new device for interventional closure of small to medium sized ASDs less than 23 mm stretched diameter in childhood. Limitations for the Solysafe device are ASDs with absent retroaortic rims and very small children with a body weight b 10 kg.
Intensive Care Medicine, 2008
Objective: To compare the assessment of cardiac output (CO) in children using the noninvasive Ult... more Objective: To compare the assessment of cardiac output (CO) in children using the noninvasive Ultrasound Cardiac Output Monitor (USCOM) with the invasive pulmonary artery catheter (PAC) thermodilution cardiac output measurement. Design and setting: Prospective observational study in a tertiary center for pediatric cardiology of a university children's hospital. Patients: Twenty-four pediatric patients with congenital heart disease without shunt undergoing cardiac catheterization under general anesthesia. Measurements and results: CO was measured by USCOM using a suprasternal CO Doppler probe in children undergoing cardiac catheterization. USCOM data were compared to CO simultaneously measured by PAC thermodilution technique. Measurements were repeated three times within 5 min in each patient. A mean percentage error not exceeding 30% was defined as indicating clinical useful reliability of the USCOM. CO values measured by PAC ranged from 1.3 to 5.3 l/min (median 3.6 l/min). Bias and precision were -0.13 and 1.34 l/min, respectively. The mean percentage error of CO measurement by the USCOM compared to PAC thermodilution technique was 36.4% for USCOM. Conclusions: Our preliminary data demonstrate that cardiac output measurement in children using the USCOM does not reliably represent absolute CO values as compared to PAC thermodilution. Further studies must evaluate the impact of incorporating effective aortic valve diameters on CO measurement using the USCOM.
Intensive Care Medicine, 2007
To investigate efficacy and safety of enoxaparin for catheter-related arterial thrombosis in infa... more To investigate efficacy and safety of enoxaparin for catheter-related arterial thrombosis in infants with congenital heart disease. Prospective observational study. Pediatric Intensive Care and Cardiology Unit at the University Children&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s Hospital of Zurich. A cohort of 32[Symbol: see text]infants aged 0-12[Symbol: see text]months treated with enoxaparin for catheter-related arterial thrombosis from 2002 to 2005. Dose requirements of enoxaparin, resolution of thrombosis by Doppler ultrasound, and bleeding complications. Catheter-related arterial thrombosis was located in the iliac/femoral arteries in 31 (97%) infants and aorta in 1 infant, and was related to indwelling catheters and cardiac catheterization in 17 (53%) and 15 (47%) cases, respectively. Newborns required increased doses of enoxaparin to achieve therapeutic anti-FXa levels (mean 1.62[Symbol: see text]mg/kg per dose) compared with infants aged 2-12 months (mean 1.12 mg/kg per dose; p=0.0002). Complete resolution of arterial thrombosis occurred in 29 (91%) infants at a mean of 23 days after initiation of enoxaparin therapy. Partial or no resolution was observed in 1 (3%) and 2 (6%) infants, respectively, at a mean follow-up time of 4.3 months. Bleeding complications occurred in 1 (3%) infant. Enoxaparin is efficient and safe for infants with congenital heart disease and catheter-related arterial thrombosis, possibly representing a valid alternative to the currently recommended unfractionated heparin.
European Journal of Cardio-Thoracic Surgery, 2011
The aim of the study was to analyze immediate results, rate of complications and re-interventions... more The aim of the study was to analyze immediate results, rate of complications and re-interventions during medium-term outcome in pediatric patients with native or recurrent aortic coarctation. We focused on an age-related therapeutic approach comparing surgical and trans-catheter treatment. This is a retrospective, single-centre, clinical observational trial including 91 consecutive patients (age: 1 day-18 years) treated for native coarctation in 67 and recurrent aortic coarctation in 24 patients. Surgical treatment was performed in 56, trans-catheter treatment with balloon dilatation in 17, and by stent implantation in 18 patients. According to the age groups, we treated 48 children in group A (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;6 months of age), 16 in group B (6 months-6 years), and 27 in group C (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;6 years). A total of 41 patients in group A were operated (85%), patients in group B received either surgical or trans-catheter treatment (50% vs 50%), and 16 patients in group C were treated by stent implantation (62%). Immediate results were excellent with a significant release of pressure gradient in all three age groups (64.7% in group A, 69.1% in group B, and 63.3% in group C). Complication rate and re-intervention rate (surgical and interventional) both were [corrected] comparable between the three age groups (complications: group A 8.3%, group B 6.3%, and group C 3.7%, [corrected] re-interventions: group A 16.6%, group B 18.8%, and group C 14.8%). [corrected] Midterm outcome after a median follow-up period of 17.5 months was satisfactory with a re-intervention-free survival after 17.5 months of 83.4%, 81.2%, and 81.5% in group A, group B, and group C, respectively. The current strategy of an age-related therapy for native and recurrent aortic coarctation in our institution is surgery in infants &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;6 months (group A), either surgery or balloon dilatation in younger patients &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;6 years (group B), while in older children &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;6 years of age (group C) the trans-catheter treatment with stent implantation is an excellent alternative to surgery. Balloon dilatations showed limited results with an overall re-intervention rate of 53% and, therefore, should mainly be performed as a rescue procedure or in recurrent aortic coarctation in neonates.
European Journal of Cardio-Thoracic Surgery, 2012
OBJECTIVE: The purpose of this study was to assess the technical feasibility of a fetal trans-api... more OBJECTIVE: The purpose of this study was to assess the technical feasibility of a fetal trans-apical stent delivery into the pulmonary artery using a novel hybrid-intervention technique as a possible route for prenatal minimally invasive heart-valve-implantation approaches.
European Journal of Cardio-Thoracic Surgery, 2014
To analyse the results of hybrid palliation of hypoplastic left heart syndrome (HLHS) patients an... more To analyse the results of hybrid palliation of hypoplastic left heart syndrome (HLHS) patients and its variants with an emphasis on the long-term fate of the pulmonary arteries. We analysed 28 neonates (2006-11) with HLHS and its variants, who underwent bilateral pulmonary artery banding, patent ductus arteriosus (PDA) stenting and balloon atrial septostomy using a true hybrid approach. Median age and weight were 4 (0-36) days and 3 (1.9-3.7) kg respectively. Diagnoses included 23 HLHS and 5 variants. The fate of all surviving branch pulmonary arteries (PA) after a hybrid approach were compared with their counterparts in 29 Norwood I survivors (2002-11). Four of 28 hybrid procedures needed to be converted to a Norwood procedure. Mortality after stage I hybrid palliation was 3/24 (12.5%). All 21 acute survivors underwent a comprehensive stage II at a median age of 4 (2.3-5.7) months, without any mortality (0%). Eleven of 21 comprehensive stage II survivors have undergone extracardiac Fontan; including 1 who underwent a rescue Fontan at 7 months of age and died (1/11: 9%). While 18/21 (86%) needed branch PA intervention in the hybrid group during the median follow-up duration of 39 (10-81) months, 9/29 (31%) needed the same in the Norwood group during a median follow-up duration of 58 (16-128) months (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). Eight of 21 (38%) needed stenting [all on the left pulmonary artery (LPA)] in the hybrid group vs 5/29 (17%) in the Norwood group (P = 0.097). Ten of 21 (48%) patients had surgical/catheter intervention on both branch PA in the hybrid group vs 2/29 (7%) in the Norwood group (P = 0.001). Pre-Fontan Nakata index was significantly better in the Norwood group 206 (118-406) compared with the hybrid group 153 (56-230) mm(2)/m(2) (P = 0.01). The comparable lower lobe indices were 149 (103-333) and 137 (45-178) mm(2)/m(2) (P = 0.04), respectively. Hybrid approach can be pursued with a low mortality. However, the high frequency of catheter and/or surgical interventions, and the sluggish growth of the branch PA pre-Fontan need innovative solutions. A comparison of the neurodevelopmental outcome for the hybrid vs the Norwood cohort would define the role of the hybrid strategy in the treatment of HLHS and its variants.
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Papers by Oliver Kretschmar