Jon Smith

The waiting game: bridging to paediatric heart transplantation

BACKGROUND Although mechanical circulatory support might not increase the number of adults surviving to transplantation, because of the shortage of donor organs, the situation might be different for children. Our aim was to assess the effect of mechanical assist devices to bridge children with end-stage cardiomyopathy to heart transplantation. METHODS A 5-year retrospective review was undertaken with data from the UK paediatric transplant programme and from bridging to transplant done at two paediatric transplant centres in the UK. FINDINGS Between Jan 1, 1998 and Dec 31, 2002, 22 children with end-stage cardiomyopathy, median age 5.7 years (range 1.2-17), were supported by a mechanical assist device as a bridge to first heart transplantation, with a 77% survival rate to hospital discharge. Nine were supported by a paracorporeal ventricular assist device, six received transplantation, five survived to discharge (55%), with one late death. 13 were supported by extra-corporeal membrane oxygenation, and 12 were transplanted and survived to discharge (92%) with one late death. With urgent listing, the median waiting time for a heart was 7.5 days (range 1.5-22 days). The correlation between the proportion of patients bridged to transplantation and the proportion of patients dying while on the transplant waiting list was r=-0.93, p=0.02. INTERPRETATION Our findings lend support to the hypothesis that a national mechanical assist programme to bridge children to transplantation can minimise the number dying while on the heart transplant waiting list. In the context of urgent listing and a short waiting time, extra-corporeal membrane oxygenation seems to provide the safest form of support.

Look away! : the U.S. South in New World studies

Look Away! considers the U.S. South in relation to Latin America and the Caribbean. Given that some of the major characteristics that mark the South as exceptional within the United States--including the legacies of a plantation economy, slave trade, and military defeat--are common to most of the Americas, Look Away! points to postcolonial studies as perhaps the best perspective from which to comprehend the U.S. South. At the same time it shows how, as part of the United States, the South--both centre and margin, victor and defeated, and empire and colony--complicates ideas of the postcolonial. The twenty-two essays in this comparative, interdisciplinary collection rethink southern U.S. identity, race, and the differences and commonalities between the cultural productions and imagined communities of the U.S. South and Latin America. Look Away! presents work by respected scholars in comparative literature, American studies, and Latin American studies. The contributors analyze how writers--including the Martinican Edouard Glissant, Cuban-American Gustavo Perez Firmat, and Trinidad-born, British V. S. Naipaul--have engaged with the southern United States. They explore William Faulkners role in Latin American thought and consider his work in relation to that of Gabriel Garcia Marquez and Jorge Luis Borges. Many essays re-examine major topics in southern U.S. culture--such as race, slavery, slave resistance, and the legacies of the past--through the lens of postcolonial theory and postmodern geography. Others discuss the South in relation to the U.S.-Mexico border. Throughout the volume, the contributors consistently re-conceptualize U.S. southern culture in a way that acknowledges its postcolonial status without diminishing its distinctiveness. Contributors: Jesse Aleman; Bob Brinkmeyer; Debra Cohen; Deborah N. Cohn; Michael Dash; Leigh Anne Duck; Wendy Faris; Earl Fitz; George Handley; Steve Hunsaker; Kirsten Silva Gruesz; Dane Johnson; Richard King; Jane Landers; John T. Matthews; Stephanie Merrim; Helen Oakley; Vincent Perez; John-Michael Rivera; Scott Romine; Jon Smith; Ilan Stavans; Philip Weinstein; Lois Parkinson Zamora

Neonatal extracorporeal membrane oxygenation: practice patterns and predictors of outcome in the UK

Objective: To review the UK neonatal extracorporeal membrane oxygenation (ECMO) service and identify predictors of outcome. Design: Retrospective review of the national cohort. Patients and interventions: 718 neonates received ECMO for respiratory failure between 1993 and 2005. Measurements and results: Diagnoses were: 48.0% meconium aspiration syndrome (97.1% survivors), 15.9% congenital diaphragmatic hernia (CDH; 57.9% survivors), 15.9% sepsis (62.3% survivors), 9.5% persistent pulmonary hypertension (79.4% survivors), 5.6% respiratory distress syndrome (92.5% survivors) and 5.1% congenital lung abnormalities (24.3% survivors). The overall survival rate of 79.7% compared favourably with the worldwide Extracorporeal Life Support Organization (ELSO) Registry. Over the period of review, pre-ECMO use of advanced respiratory therapies increased (p<0.001), but ECMO initiation was not delayed (p = 0.61). The use of veno-venous (VV) ECMO increased (p<0.001) and average run time fell (p = 0.004). Patients treated with VV ECMO had a survival rate of 87.7% compared with 73.4% in the veno-arterial (VA) ECMO group; only 42.4% of those needing conversion from VV to VA ECMO survived. In non-CDH neonates, lower birth weight, lower gestational age, older age at ECMO and higher oxygenation index (OI) were associated with increased risk of death. In CDH neonates, lower birth weight and younger age at ECMO were identified as risk factors for death. Conclusion: The UK neonatal ECMO service achieves good outcomes and with overall survival rate reaching 80% compares favourably with international results. Advanced respiratory therapies are used widely in UK ECMO patients. Identification of higher OI and older age at ECMO as risk factors in non-CDH neonates reinforces the importance of timely referral for ECMO.

Thoratec CentriMag for Temporary Treatment of Refractory Cardiogenic Shock or Severe Cardiopulmonary Insufficiency: A Systematic Literature Review and Meta-Analysis of Observational Studies

The aim of the study was to systematically evaluate effect of CentriMag heart pump (Thoratec Corporation) as temporary ventricular assist device (VAD) and part of extracorporeal membrane oxygenation (ECMO) system on outcomes in patients with cardiac or cardiac-respiratory failure. A systematic search was conducted in five databases for the period 2003 to 2012. Fifty-three publications with data for 999 patients, supported with CentriMag, were included. In 72% studies, CentriMag was used as a VAD and in 25% as part of ECMO circuit. Mean duration of VAD support was 25.0 days in precardiotomy group, 10.9 days in postcardiac surgery cardiogenic shock group, 8.8 days in post-transplant graft failure and rejection group, and 16.0 days in post-LVAD placement right ventricular failure group. Survival on support was 82% (95% CI 70–92) for VAD support in precardiotomy cardiogenic shock indication, 63% (95% CI 46–78) in VAD support in postcardiac surgery cardiogenic shock indication, 62% (95% CI 46–76) in VAD support in post-transplant graft rejection or failure indication, and 83% (95% CI 73–92) in VAD support in post-LVAD placement right ventricular failure indication. CentriMag is an effective technology for temporary support of patients with cardiac and cardiorespiratory failure.

The use of left heart bypass in adult and recurrent coarctation repair.

OBJECTIVES Paraplegia following coarctation repair occurs in 0.4% of infants. However, for older children, adults and re-operations, the incidence can be as high as 2.6%. Yet there is no consensus on the need for spinal cord protection or the optimal method. This paper reports our experience with left heart bypass (LHB) in adult and re-do coarctation. METHODS Between 1997 and 2000, nine patients underwent elective resection of coarctation (three re-dos, two balloons) with a mean age of 17.9 years (range, 8-44) and weight of 52 kg (range, 17.3-109). The mean trans-coarctation gradient was 29.6 mmHg (range, 20-45). Patients were placed on LHB using a centrifugal pump with full heparinization through a fourth-space thoracotomy. Patients were cooled to 31-34 degrees C for additional spinal cord protection. Repair was carried out with an inter-positional graft (5/9), a Gore-Tex patch (2/9) or end-to-end anastomosis (2/9). The mean cross-clamp and bypass times were 36.4 (range, 19-65) and 40.3 min (range, 22-70), respectively. RESULTS No patient developed transient or permanent paraplegia. The mean peak creatinine was 80 micromol/l (range, 51-123). CONCLUSIONS LHB is simple, easy and safe to implement, and is the only technique capable of maintaining independent upper and lower body perfusion pressure. Potentially, it provides the best spinal cord protection, and extends the margin of safety and time to execute an accurate repair.

General Anesthesia for Children With Severe Heart Failure

Severe heart failure in children is uncommon. The anesthetic management of children with this condition is challenging. The authors aimed to identify the frequency with which anesthesia for short noncardiac surgical procedures or investigations was complicated by life-threatening hemodynamic instability and to describe the anesthetic techniques used. This study retrospectively reviewed the anesthetic charts and notes of children admitted acutely with a diagnosis of severe heart failure (fractional shortening of 15% or less) who received general anesthesia for noncardiac surgical or diagnostic interventions during the 3-year period from September 2005 to September 2008. In this study, 21 children received a total of 28 general anesthetics. Two patients (10%) experienced a cardiac arrest, and both required unplanned admission to the authors’ pediatric intensive care unit (PICU) postoperatively. A variety of anesthetic techniques was used. In 27 (96%) of the 28 cases, perioperative inotropic support was required. General anesthesia for children with severe heart failure is associated with a significant complication rate and should be administered by anesthetists familiar with managing all aspects of circulatory support for children in an appropriate setting.

Outcome of mechanical cardiac support in children using more than one modality as a bridge to heart transplantation

OBJECTIVES Mechanical cardiac support (MCS) can successfully be applied as a bridging strategy for heart transplantation (OHTx) in children with life-threatening heart failure. Emergent use of MCS is often required before establishing the likelihood of OHTx. This can require bridge-to-bridge strategies to increase survival on the waiting list. We compared the outcome of children with heart failure who underwent single MCS with those who required multiple MCS as a bridge to OHTx. METHODS A retrospective study of patients aged less than 16 years was conducted. From March 1998 to October 2005, we used either a veno-arterial extracorporeal membrane oxygenator (VA-ECMO), or the Medos® para-corporeal ventricular assist device (VAD). From November 2005 onwards, the Berlin Heart EXCOR® (BHE) device was implanted in the majority of cases. Several combinations of bridge-to-bridge strategies have been used: VA-ECMO and then conversion to BHE; BHE and then conversion to VA-ECMO; left VAD and then upgraded to biventricular support (BIVAD); conversion from pulsatile to continuous-flow pumps. RESULTS A total of 92 patients received MCS with the intent to bridge to OHTx, including 21 (23%) supported with more than one modality. The mean age and weight at support was similar in both groups, but multimodality MCS was used more often in infancy (P = 0.008) and in children less than 10 kg in weight (P = 0.02). The mean duration of support was longer in the multiple MCS group: 40 ± 48 vs 84 ± 43 days (P = 0.0003). Usage of multimodality MCS in dilated cardiomyopathy (19%) and in other diagnoses (29%) was comparable. Incidence of major morbidity (haematological sequelae, cerebrovascular events and sepsis) was similar in both groups. Survival to OHTx/explantation of the device (recovery) and survival to discharge did not differ between single MCS and multiple MCS groups (78 vs 81% and 72 vs 76%, respectively). CONCLUSION Bridge to OHTx with multiple MCS does not seem to influence the outcome in our population. Infancy and body weight less than 10 kg do not tend to produce higher mortality in the multiple MCS group. However, children receiving more than one modality are supported for longer durations.

Predicting outcome in ex-premature infants supported with extracorporeal membrane oxygenation for acute hypoxic respiratory failure

Objective: To identify predictors of outcome in ex-premature infants supported with extracorporeal membrane oxygenation (ECMO) for acute hypoxic respiratory failure. Methods: Retrospective review of ex-premature infants with acquired acute hypoxic respiratory failure requiring ECMO support in the United Kingdom from 1992 to 2001. Review of follow up questionnaires completed by general practitioners and local paediatricians. Results: Sixty four ex-premature infants (5–10 each year) received ECMO support, despite increased use of advanced conventional treatments over the decade. The most common infective agent was respiratory syncytial virus (85% of cases). Median birth gestation was 29 weeks and median corrected age at the time of ECMO support was 42 weeks. Median ECMO support duration was relatively long, at 229 hours. Survival to hospital discharge and to 6 months was 80%, remaining similar throughout the period of review. At follow up, 60% had long term neurodisability and 79% had chronic pulmonary problems. Of pre-ECMO factors, baseline oxygen dependence, younger age, and inpatient status were associated with non-survival (p ⩽ 0.05). Of ECMO related factors, patient complications were independently associated with adverse neurodevelopmental outcome and death (p < 0.01). Conclusions: Survival rates for ex-premature infants after ECMO support are favourable, but patients suffer a high burden of morbidity during intensive care and over the long term. At the time of ECMO referral, baseline oxygen dependence is the most important predictor of death, but no combination of the factors considered was associated with a mortality that would preclude ECMO support.

Histology of the explanted hearts of children transplanted for dilated cardiomyopathy

Abstract:  There is little information as to the histology of the explanted hearts of children transplanted for presumed dilated cardiomyopathy. We therefore aimed to describe the histology of these explants. Thirty‐six children [mean age 7.4 years (range 0.1–17)] transplanted for dilated cardiomyopathy were identified. Based on histological examination of the explanted hearts patients were classified into three groups: severe inflammation, mild to moderate inflammation, and minimal or no inflammation. Cell death/damage and fibrosis were also scored. Duration of symptoms and degree of support at transplant were ascertained from the case notes. Two patients had severe confluent inflammation, nine mild or moderate focal inflammation, and 25 minimal or no inflammation. The degree of inflammation and fibrosis did not correlate with the interval between presentation and transplant (p = 0.37 and p = 0.78). Patients requiring inotropes or ventricular assist had a shorter time interval between presentation and transplant (p = 0.017) although these levels of support were not associated with the degree of inflammation or fibrosis (p = 0.90 and 0.5). We conclude that the explanted hearts of one‐third of children transplanted for presumed cardiomyopathy have some degree of inflammation. Histological findings are not associated with symptom duration or support required.

Acute rhabdomyolysis after cardiac transplantation: a diagnostic conundrum

Summary A 13‐year‐old girl presented with right ventricular failure secondary to Ebsteins malformation (downward displacement of the tricuspid valve leaflets with adherence to the right ventricular muscle and redundancy or dysplasia of the tricuspid valve leaflets). She subsequently required a heart transplant but developed rhabdomyolysis early in the postoperative period and required ventilatory support for more than 3 weeks. A variety of causes were considered, but her condition improved only when cyclosporin was eliminated from the immunosuppression regimen. We believe it is likely that the rhabdomyolysis has been caused by cyclosporin. If so, this has occurred both earlier in the clinical course and at lower serum concentrations than previously described.