Carin Van Doorn - Academia.edu (original) (raw)

Papers by Carin Van Doorn

A two month old Ugandan boy underwent surgery for an obstructive right ventricular vegetation ass... more A two month old Ugandan boy underwent surgery for an obstructive right ventricular vegetation associated with disseminated Staphylococcus aureus infection. Both the child and his mother subsequently tested positive for HIV infection. Very little is know about the incidence of endocarditis in paediatric patients with AIDS. To our knowledge this is the first case reported of disseminated S aureus infection associated with endocarditis and an obstructing vegetation in an HIV positive infant with a structurally normal heart. The initial signs and symptoms for endocarditis were atypical, a reflection of the overwhelming infection in an immunocompromised patient. Severe infections may have an atypical presentation in immunosuppressed patients. AIDS needs to be considered in these patients, especially if they come from populations with endemic HIV infection.

Journal of the American Society of Echocardiography, 2010

The authors present the unique case of an 8-month-old baby diagnosed with severe left ventricular... more The authors present the unique case of an 8-month-old baby diagnosed with severe left ventricular failure of unknown etiology. Due to a lack of organ availability for this age, a mechanical assist device and assessment for cardiac transplantation were not offered. Subsequent comprehensive echocardiographic dyssynchrony assessment and the presence of left bundle branch block were suggestive of response to cardiac resynchronization therapy. Dual-chamber epicardial pacing was initiated, resulting in prompt marked clinical and echocardiographic improvement, which continued until complete normalization of cardiac function. The pacing system was safely turned off 6 months after its implantation. In conclusion, cardiac resynchronization therapy should be considered as a treatment option even in infancy, regardless of the etiology of disease and/or patient age.

Journal of Cardiac Surgery, 1997

Background and Aims: Skeletal muscle ventricles (SMVs) are a potential power source for circulato... more Background and Aims: Skeletal muscle ventricles (SMVs) are a potential power source for circulatory assistance. Noninvasive assessment of SMVs is desirable in long-term studies of SMV function. This study evaluated whether tissue velocity imaging (TVI) indices of function correlate with invasive measurements of output and pressure generation and examined the potential of TVI to provide information about SMV geometry and wall contraction characteristics. Methods: SMVs were constructed in six sheep. After electrical conditioning, SMVs were connected to a mock circulation and stimulated with supramaximal 30-Hz and 50-Hz bursts to contract 35 timeslmin. The SMVs were tested over a range of preloads, and afterload was adjusted to simulate systemic (80 mmHg) and right ventricular (30 mmHg) loading conditions. Stroke volume and pressure were measured invasively, and stroke work was calculated. TVI was used to measure velocities in two opposing SMV walls, providing a simple wall motion score (WMS). This was evaluated against stroke volume, stroke work, and pressure development. Results: 50-Hz stimulation frequency and high preload optimized SMV performance. Optimal SMV performance indices (mean at 50 Hz) were as follows: (a) right ventricular loading conditions (preload 30 mmHg), stroke volume 17.6 mL (SEM 3.2), peak pressure over afterload 44.2 mmHg (10.9), stroke work 0.05 J (0.02); (b) systemic loading conditions (preload 60 mmHg), stroke volume 10.1 mL (3.2), peak pressure over afterload 58 mmHg (14.6), stroke work 0.08 J (0.03). With low preloads, geometric anomalies were noted in the SMVs using TVI. Collapse of the SMVs and dyskinesis were observed, which normalized with higher preloads. Persistent dyskinesis was noted in one SMV and was associated with poor performance. Correlations (at optimal loading and stimulation settings) were as follows: systemic loading conditions, stroke volume versus WMS, 0.92 (p = 0.026); peak pressure versus WMS 0.89 (p = 0.045); stroke work versus WMS, r = 0.91 (p = 0.046). Right ventricular loading conditions were as follows: stroke volume versus WMS, 0.63 (p = 0.25); peak pressure versus WMS, 0.66 (p = 0.22); stroke work versus WMS, 0.45 (p = 0.39). Conclusion: Under systemic loading conditions, TVI indices of SMV wall motion mirror invasive indices of performance, suggesting that TVI may be a useful tool for long-term noninvasive monitoring of SMV function.

Effects of Cardiomyoplasty on Cardiac Growth in Rats

Journal of Cardiac Surgery, 1996

... Catharina AM van Doorn, FRCS,' Moninder S. Bhabra, FRCS,' Reida M. El Oakley, FRCS,... more ... Catharina AM van Doorn, FRCS,' Moninder S. Bhabra, FRCS,' Reida M. El Oakley, FRCS," Jonathan C. Jarvis, B.Sc., Ph.D.,*" Stanley Salmons, M ... Sam-ples were quick-frozen in melting isopentane, then 10-pm sections were then cut in a cryostat, air dried, and stained with hema ...

Archives of Disease in Childhood, 1998

The Annals of Thoracic Surgery, 1996

Background. Damage in latissimus dorsi muscle flaps has been reported after clinical and experime... more Background. Damage in latissimus dorsi muscle flaps has been reported after clinical and experimental cardiomyoplasty, and an ischemic origin has been suggested. Methods. In situ, preconditioned latissimus dorsi muscles in 5 sheep were stimulated in either 1:1 (muscle: heart) or 1:2 synchrony with the systolic phase of the cardiac cycle, using a burst duration of either 21% or 35% of the cycle. Thoracodorsal artery blood flow and thoracodorsal venous lactate concentrations were measured before and immediately after a 3-minute period of stimulation. Results. The exercise-induced augmentation of thoracodorsal artery blood flow was significantly (p < 0.05) less with a 1:2 regimen than a 1:1 regimen, for both a 21% (88%; 95% confidence interval [CI], 55.6% to 127.3% versus 138.9%; CI, 97.6% to 188.8%) and 35% burst duration (123.2%; CI, 84.7% to 169.9% versus 167.0; CI, 120.8% to 222.6%). After cessation of stimulation, reactive hyperaemia was observed in 3 of 5 animals with 1:1 21% burst stimulation, and in 5 of 5 animals with a 35% burst duration, but was not seen after 1:2 regimens. A significant (p < 0.01) increase in thoracodorsal venous lactate levels was present after 1:1 35% burst stimulation (34.9%; CI, 9.9% to 65.6%), but lactate levels tended to fall when a 1:2 ratio was used (15.9%; CI,-3.2% to 31.5%; p < 0.1). Conclusions. One-to-one stimulation regimens may be detrimental to latissimus dorsi blood flow, and an adaptive, rather than fixed, burst duration may be preferable. These findings have important implications for the cardiomyoplasty procedure.

Influence of ivabradine on reverse remodelling during mechanical unloading

Cardiovascular Research, 2013

Sequential use of extracorporeal membrane oxygenation and the Berlin Heart Left Ventricular Assist Device for 106-day bridge to transplant in a two-year-old child

ASAIO journal (American Society for Artificial Internal Organs : 1992)

We describe a 2 year-old girl with end-stage dilated cardiomyopathy in whom extracorporeal membra... more We describe a 2 year-old girl with end-stage dilated cardiomyopathy in whom extracorporeal membrane oxygenation (ECMO) was used for mechanical cardiac assistance. After 4 weeks, ECMO-related complications necessitated change to a Berlin Heart Left Ventricular Assist Device (LVAD), and she received a successful cardiac transplant after a total of 106 days on mechanical cardiac support.

Improved early outcome for end-stage dilated cardiomyopathy in children

To review the impact of management changes on the early outcomes of end-stage dilated cardiomyopa... more To review the impact of management changes on the early outcomes of end-stage dilated cardiomyopathy in children. We conducted a retrospective study of all consecutive children with end-stage dilated cardiomyopathy who received hospital treatment since 1992. Over the past 3 years the following management changes were made: (1) more aggressive use of mechanical cardiac assistance; (2) high priority listing for transplantation; and (3) ABO incompatible transplants for infants. Outcomes for 46 patients admitted between 1992 and 1999 (group I) were compared with 53 patients between 2000 and March 2003 (group II). In group I, 12 (26%) patients received mechanical support with recovery in 3 and transplantation in 5 (1 died). In group II, 19 (36%) patients received extracorporeal membrane oxygenation, with recovery in 5 and transplantation in 12 (all survived). The use of mechanical assistance was associated with high morbidity related to bleeding, end-organ failure, and long-term mechanical ventilation. Five patients in group II received ABO incompatible transplants and all survived. There have been no episodes of rejection or need for increased immunosuppressive therapy. Hospital mortality has been significantly reduced (group I, 37% vs group II, 11%; 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;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;.05). Recent refinements in the management of end-stage dilated cardiomyopathy in children have significantly reduced early mortality. Identification of markers of early myocardial recovery and development of mechanical devices for longer term and more physiologic support are essential to achieve further improvements in outcome.

Impact of combined clenbuterol and metoprolol therapy on reverse remodelling during mechanical unloading

PloS one, 2014

Clenbuterol (Cl), a β2 agonist, is associated with enhanced myocardial recovery during left ventr... more Clenbuterol (Cl), a β2 agonist, is associated with enhanced myocardial recovery during left ventricular assist device (LVAD) support, and exerts beneficial remodelling effects during mechanical unloading (MU) in rodent heart failure (HF). However, the specific effects of combined Cl+β1 blockade during MU are unknown. We studied the chronic effects (4 weeks) of β2-adrenoceptor (AR) stimulation via Cl (2 mg/kg/day) alone, and in combination with β1-AR blockade using metoprolol ((Met), 250 mg/kg/day), on whole heart/cell structure, function and excitation-contraction (EC) coupling in failing (induced by left coronary artery (LCA) ligation), and unloaded (induced by heterotopic abdominal heart transplantation (HATx)) failing rat hearts. Combined Cl+Met therapy displayed favourable effects in HF: Met enhanced Cl's improvement in ejection fraction (EF) whilst preventing Cl-induced hypertrophy and tachycardia. During MU combined therapy was less beneficial than either mono-therapy. Met...

ECLS for children with late (post-discharge) rejection after heart transplantation

Pediatric Transplantation, 2013

Rejection with acute hemodynamic compromise after OHT is rare in children, and is associated with... more Rejection with acute hemodynamic compromise after OHT is rare in children, and is associated with poor survival. We retrospectively reviewed the management, course and outcome of recipients with late (following initial hospital discharge) rejection with acute hemodynamic compromise who were supported on ECLS. Of 197 consecutive children undergoing OHT (84 male; mean [SD] age 8.3 [5.7] [range 0.1-18.8 yr]) between 2/2002 and 10/2012, 187 children survived and were discharged from hospital. Mean (SD) follow-up was 5.0 (3.1) (range 0.1-10.6) yr. During follow-up, seven presented with severe hemodynamic compromise after transplantation (of whom one patient had been transplanted elsewhere). All seven children, who presented in hemodynamic collapse with poor cardiac function refractory to inotropic support, were placed on ECLS-two following in-hospital cardiac arrest. The median duration of ECLS was 6 (range 5-15) days. All survived to decannulation, with one death from overwhelming sepsis 20 days after presentation. The median (range) duration (in days) of inotropic requirement post ECLS was 11 (5-27), the median ventilation time was 8 (7-30), median ICU length of stay was 14 (10-54), and median hospitalization was 24 (19-118). In all, ventricular function normalized (FS &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;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;gt;28%) within 10 (7-22) days. There was significant short-term morbidity; however, over a median follow-up of 5.9 (range 0.7-9.2) yr, all survivors have good functional status with no significant apparent neurological sequelae. ECLS thus appears to be a good rescue therapy for children with severe acute rejection post OHT, refractory to conventional treatment, leading to good medium-term outcome.

Journal of Surgical Research, 2013

Introduction: Chronic changes in mechanical load regulate long-term cardiac function.

The Journal of Heart and Lung Transplantation, 2011

European Journal of Cardio-Thoracic Surgery, 2011

Objective: Infants and young children are considered the most difficult group to bridge to orthot... more Objective: Infants and young children are considered the most difficult group to bridge to orthotopic heart transplantation (OHT) and data regarding outcomes are scarce. Methods: We reviewed our patients 10 kg with those who were bridged to OHT using ventricular assist device (VAD) Berlin Heart (BH) Excor AE extracorporeal membrane oxygenation (ECMO) between 2004 and 2009. Results: Eleven children 10 kg with end-stage heart failure (cardiomyopathy or myocarditis) were treated with VAD as bridge to OHT: the median weight was 8.0 (range 3.9-10.0 kg) kg and median age was 12.3 (range 1.2-33.9 months) months. Five (45%) required ECMO support pre-BH and six were on mechanical ventilation and inotropes. In 9/11 (82%), the support mode was left ventricular assist device (L-VAD) (all alive): one of two patients needing Bi-VAD support died. On BH, the median support time was 27 days and time to extubation was 8 days. Two out of 11 (18%) suffered strokes confirmed on brain imaging; both recovered and one underwent resection of infarcted small bowel. Ten out of 11 (91%) were transplanted, one remains in hospital and nine are at home in good health. When compared to patients >10 kg bridged with BH (n = 15), the mortality ( p = 0.51) and rates of neurological complications ( p = 0.54) were similar. Post-transplant recovery (ventilation times and time to home discharge) was similar between the bridged children 10 kg and non-bridged children 10 kg who underwent OHT. Conclusions: Mechanical bridging to transplantation is clinically feasible in children 10 kg, achieving excellent outcomes. Judicious use of VADs in smaller children will optimise the use of donor organs; however, the effect on overall OHT waiting times, if mechanical bridging was extended to a large number of small children, is unknown. #

Current approaches to pulmonary regurgitation☆☆☆

European Journal of Cardio-Thoracic Surgery, 2008

To evaluate the effects on ventricular function and volumes following right ventricular outflow t... more To evaluate the effects on ventricular function and volumes following right ventricular outflow tract reconstruction (RVOTR) with pulmonary homograft replacement (PVR) and percutaneous pulmonary valve implantation (PPVI) for predominant pulmonary regurgitation. This study was not intended to compare the two approaches. We prospectively examined 25 patients (mean age 21+/-13 years, 96% tetralogy of Fallot, 1/25 with conduit dysfunction) who had PVR with RVOTR for severe pulmonary regurgitation (PR), and 11 patients (mean age 20+/-9 years, 64% tetralogy of Fallot, 9/11 with conduit dysfunction) who underwent PPVI for predominant PR. Mean age at primary repair in both groups was 4.3+/-6.6 years. Magnetic resonance imaging was performed prior to, and 1 year following, interventions. Before procedure, NYHA classification was similar in both groups 2.1+/-0.5. Following interventions, there was a significant reduction in RV volumes in both groups. In the surgical (PVR) group, RV end-diastolic volume (EDV) decreased from 151+/-49 to 97+/-32 ml/m(2) (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;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;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;0.0001) whereas end-systolic volume (ESV) decreased from 80+/-43 to 46+/-23 ml/m(2) (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;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;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;0.0001). In the PPVI group, RV EDV decreased from 106+/-27 to 89+/-25 ml/m(2) (p=0.002) and RV ESV from 49+/-20 to 40+/-16 ml/m(2) (p=0.034). Both groups had a significant improvement in RV (63+/-20 to 72+/-16 ml/beat, p=0.003 (PVR group), 53+/-14 to 67+/-16 ml/beat, p=0.030 (PPVI group)) and LV effective stroke volume (61+/-18 to 73+/-16 ml/beat, p=0.001 (PVR group); 59+/-24 to 75+/-16 ml/beat, p=0.009 (PPVI group)). Following either PVR with RVOTR or PPVI, there was a significant reduction in RV volumes and an improvement in RV function. Importantly, in both groups, LV effective SV increased, and this may be the parameter to judge the benefit of the procedure. These results also support PPVI as an extra dimension in complex RVOT management.

European Journal of Cardio-Thoracic Surgery, 2005

Objective: To assess the impact of a percutaneous technique for pulmonary valve implantation on t... more Objective: To assess the impact of a percutaneous technique for pulmonary valve implantation on the conventional surgical valve/conduit approach to right ventricular outflow tract re-intervention. Methods: We have retrospectively reviewed our results following surgical or percutaneous re-intervention to the right ventricular outflow tract in both paediatric and adult groups. Between November 1998 and March 2004, 94 patients underwent surgical re-intervention to the right ventricular outflow tract. Percutaneous pulmonary valve implantation was introduced in October 2002 and 35 procedures were performed to March 2004. The median age was 26 years (6-65 years) in the surgical group and 16 years (9-39 years) in the percutaneous group. Tetralogy of Fallot was the commonest original diagnosis (64.9 and 62.9%, respectively). The predominant indication for re-intervention in the surgical group was pulmonary regurgitation (64.9%) compared to the percutaneous group in which it was homograft/conduit stenosis or a mixed lesion (68.6%). Results: There has been one (1.1%) early death reported in the surgical series and none in the percutaneous group. In the surgical group 9 (9.6%) experienced a procedural complication whilst 3 (8.5%) of those undergoing a percutaneous valve experienced a significant procedural event necessitating urgent surgery. Important early morbidity was 8 (8.5%) in the surgical group and 2 (5.7%) in the percutaneous group. Freedom from re-operation at 1 year was 100% in the surgical group and 86.1% in the percutaneous group due to late restenosis. Median hospital stay in the surgical group was 7 (4-114) days and 2 (2-22) days in the percutaneous group. Conclusions: Preliminary data suggests that percutaneous pulmonary valve implantation provides a promising additional and complementary approach to a successful surgical programme. Both approaches are safe with acceptable levels of morbidity and low mortality. With current technology the aneurysmal outflow tract remains a problem for the percutaneous approach. Follow-up remains too short, at present, to prove longevity of the percutaneous conduit. q

The Annals of Thoracic Surgery, 2007

Background. Surgery for congenital heart disease (CHD) has changed considerably during the last t... more Background. Surgery for congenital heart disease (CHD) has changed considerably during the last three decades. The results of primary repair have steadily improved, to allow treating almost all patients within the pediatric age; nonetheless an increasing population of adult patients requires surgical treatment. The objective of this study is to present the early surgical results of patients who require surgery for CHD in the adult population within a multicentered European study population.

European Heart Journal, 2010

An 11-year-old girl with aortic stenosis diagnosed at the age of 2 years presented with a 3-year ... more An 11-year-old girl with aortic stenosis diagnosed at the age of 2 years presented with a 3-year history of increasing effort angina, syncope, and NYHA class IV. A transthoracic echocardiogram revealed a dysplastic trileaflet aortic valve with a peak gradient of 70 mmHg. The left ventricle (LV) was divided into two separate chambers by a thick non-contractile membrane traversing the LV cavity horizontally at the level of the papillary muscles.