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.

Mechanical cardiac support in children with congenital heart disease with intention to bridge to heart transplantation†.

OBJECTIVES: A significant number of children affected by congenital heart disease (CHD) develop heart failure early or late after surgery, and heart transplantation (OHTx) remains the last treatment option. Due to shortage of donor organs in paediatric group, mechanical circulatory support (MCS) is now routinely applied as bridging strategy to increase survival on the waiting list for OTHx. We sought to assess the impact of MCS as intention to bridge to OHTx in patients with CHD less than 16 years of age. METHODS: From 1998 to 2013, 106 patients received 113 episodes of MCS with paracorporeal devices as intention to bridge to OHTx. Twenty-nine had CHD, 15 (52%) with two-ventricle (Group A) and 14 (48%) with single-ventricle physiology (Group B). In Group A, 5 children had venoarterial extracorporeal membrane oxygenation (VA ECMO), 6 left ventricular assist device (LVAD), 2 biventricular assist device (BIVAD), 1 VA ECMO followed by BIVAD and 1 BIVAD followed by VA ECMO. In Group B, VA ECMO was used in 7 children, univentricular assist device (UVAD) changed to VA ECMO in 4, UVAD in 2 and surgical conversion to two-ventricles physiology with BIVAD support changed to VA ECMO in 1. RESULTS: Twenty-one of 29 (72%) children survived to recovery/OHTx. Seven of 29 (59%) survived to discharge. In Group A, 11/15 (73%) survived to recovery/OHTx and 9/15 (60%) survived to discharge. Four of 15 (27%) died awaiting OHTx. One child had graft failure requiring VA ECMO and was bridged successfully to retransplantation. One child dying after OHTx had acute rejection, was supported with VA ECMO and then BIVAD but did not recover. One patient had an unsuccessful second run on BIVAD 1 year after recovery from VA ECMO. In Group B, 10/14 (71%) survived to recovery/OHTx and 8/14 (57%) survived to discharge. Four of 14 (29%) died awaiting OHTx. Of deaths after OHTx, 1 occurred intraoperatively and 1 was consequent to graft failure and had an unsuccessful second run with VA ECMO. CONCLUSIONS: Children with CHD can be successfully bridged with MCS to heart transplantation. Single-ventricle circulation compared with biventricular physiology does not increase the risk of death before transplant or before hospital discharge.

Retinal ganglion cells are resistant to photoreceptor loss in retinal degeneration.

The rapid and massive degeneration of photoreceptors in retinal degeneration might have a dramatic negative effect on retinal circuits downstream of photoreceptors. However, the impact of photoreceptor loss on the morphology and function of retinal ganglion cells (RGCs) is not fully understood, precluding the rational design of therapeutic interventions that can reverse the progressive loss of retinal function. The present study investigated the morphological changes in several identified RGCs in the retinal degeneration rd1 mouse model of retinitis pigmentosa (RP), using a combination of viral transfection, microinjection of neurobiotin and confocal microscopy. Individual RGCs were visualized with a high degree of detail using an adeno-associated virus (AAV) vector carrying the gene for enhanced green fluorescent protein (EGFP), allowed for large-scale surveys of the morphology of RGCs over a wide age range. Interestingly, we found that the RGCs of nine different types we encountered were especially resistant to photoreceptor degeneration, and retained their fine dendritic geometry well beyond the complete death of photoreceptors. In addition, the RGC-specific markers revealed a remarkable degree of stability in both morphology and numbers of two identified types of RGCs for up to 18 months of age. Collectively, our data suggest that ganglion cells, the only output cells of the retina, are well preserved morphologically, indicating the ganglion cell population might be an attractive target for treating vision loss.

Heat shock protein 27 is increased in cyanotic tetralogy of Fallot myocardium and is associated with improved cardiac output and contraction.

Tetralogy of Fallot (TOF) is a congenital heart condition in which the right ventricle is exposed to cyanosis and pressure overload. Patients have an increased risk of right ventricle dysfunction following corrective surgery. Whether the cyanotic myocardium is less tolerant of injury compared to non-cyanotic is unclear. Heat shock proteins (HSPs) protect against cellular stresses. The aim of this study was to examine HSP 27 expression in the right ventricle resected from TOF patients and determine its relationship with right ventricle function and clinical outcome. Ten cyanotic and ten non-cyanotic patients were studied. Western blotting was used to quantify HSP 27 in resected myocardium at (1) baseline (first 15 min of aortic cross clamp and closest representation of pre-operative status) and (2) after 15 min during ischemia until surgery was complete. The cyanotic group had significantly increased haematocrit, lower O2 saturation, thicker interventricular septal wall thickness and released more troponin-I on post-operative day 1 (p < 0.05). HSP 27 expression was significantly increased in the < 15 min cyanotic compared to the < 15 min non-cyanotic group (p = 0.03). In the cyanotic group, baseline HSP 27 expression also significantly correlated with oxygen extraction ratio (p = 0.028), post-operative basal septal velocity (p = 0.036) and mixed venous oxygen saturation (p = 0.02), markers of improved cardiac output/contraction. Increased HSP 27 expression and associated improved right ventricle function and systemic perfusion supports a cardio-protective effect of HSP 27 in cyanotic TOF.

Acute B-type natriuretic peptide response and early postoperative right ventricular physiology following tetralogy of Fallot's repair.

B-type natriuretic peptide (BNP) response early after a tetralogy of Fallot's repair remains unclear. BNP was measured pre- and post-operatively (immediately, day 1) in 18 children undergoing corrective repair with concurrent echocardiography (pre-, post-op day 1) to assess right ventricular (RV) systolic dysfunction, restrictive physiology, wall motion and pulmonary regurgitation (PR). In the first 24 h postoperatively, BNP rose acutely in all patients (mean 34.9 vs 144.4 vs 716.9 pg/ml at pre-op, days 0 and 1; P < 0.001). Immediate postoperative BNP correlated with preoperative haematocrit (rho = 0.52, P = 0.03) and inversely with preoperative oxygen saturation (rho = -0.63, P = 0.007). All patients showed reduced RV systolic function and abnormal wall motion with at least moderate PR in six patients (33.3%) and restrictive physiology in four (24%). Subsequent BNP expression (post-op day 1) correlated with a low RV fractional area change (rho = -0.51, P = 0.04), high oxygen extraction ratio (rho = 0.56, P = 0.02) and high central venous pressure (rho = 0.79, P < 0.001). The LV function and wall motion remained preserved in all patients. The mechanism of BNP expression is likely to be multi-factorial in the presence of a complex postoperative RV physiology in tetralogy of Fallot. An acute BNP response in the early postoperative period reflects an important physiological role and may be used as an adjunct biomarker to assess the RV function.

Comprehensive preassessment form for adult cardiac surgery.

Comprehensive evaluation of our patients before putting them under "the knife" can never be overemphasized. It is our duty to care for the patients. Detailed history-taking, clinical examination, and investigations are mandatory prior to surgery. For many years, we have striven to make our method thorough and safe for all patients. We propose here a simple, comprehensive preassessment form that is easily applicable in any unit.

Myocardial expression of heat shock protein 70i protects early postoperative right ventricular function in cyanotic tetralogy of Fallot.

BACKGROUND: Right ventricular dysfunction occurs after tetralogy of Fallot repair and may relate to greater myocardial vulnerability to ischemia-reperfusion injury in cyanotic patients. The inducible form of heat shock protein 70 (HSP-70i), a molecular chaperone, is upregulated in response to cellular stress and limits myocardial injury against ischemia-reperfusion. We evaluated the myocardial expression of HSP-70i and its relation to right ventricular function and clinical outcome in patients with tetralogy of Fallot undergoing corrective surgery. METHODS: Twenty patients with tetralogy of Fallot were studied: 10 cyanotic (group Cy) and 10 noncyanotic (group noCy). Western blot was used to quantify HSP-70i from resected right ventricular outflow tract myocardium at baseline and subsequent ischemic time. Biventricular function was quantified by tissue Doppler echocardiography and compared with that of 15 age-matched healthy children. Postoperative systemic perfusion was assessed by mixed venous oxygen saturation, oxygen extraction ratio, and lactate. RESULTS: Group Cy had thicker septum (median 0.85 vs 0.66 cm; P = .01) and longer crossclamp time (median 100.0 vs 67.5 minutes; P = .004). There were no difference in HSP-70i between groups at baseline (4.12 vs 3.44 relative optical density; P = .45) or subsequent ischemic time. Preoperative biventricular systolic function was reduced in patients with tetralogy compared with controls with further postoperative right ventricular impairment. Group Cy had higher troponin-I levels (median 16.5 vs 11.1 ng/mL; P = .04) and inotrope scores (14.0 vs 6.5; P = .05) but no differences in ventricular function, mixed venous oxygen saturation, oxygen extraction ratio, and lactate between groups. In group Cy, baseline HSP-70i correlated with better postoperative right ventricular function (rho = 0.80; P = .009), mixed venous oxygen saturation (rho = 0.68; P = .04), and oxygen extraction ratio (rho = -0.71; P = .03). These relationships were absent in group noCy. CONCLUSIONS: The association of HSP-70i expression with improved right ventricular function and systemic perfusion suggests an important cardioprotective effect of HSP-70i in cyanotic tetralogy of Fallot.

Conduits for coronary artery bypass surgery: the quest for second best.

Coronary artery bypass grafting is one of the most outstanding surgical achievements of the 20th century. Over its 50-year history patient outcomes have become excellent owing to technical refinements, myocardial protection, the use of antiplatelet and anticholesterol drugs, and the continued search for better conduits. The performance of conduits used for bypass remains the most important prognostic factor, with the left internal mammary artery being the conduit of choice due to its excellent patency rates. There is, however, uncertainty with regards which conduit is second best. The recent resurgence of the radial artery has led to an increase in its use as surgeons lean towards total arterial revascularization but there is emerging evidence that the performance of the long saphenous vein graft is improving. Furthermore, bilateral internal mammary artery grafting is preferred in some centres as an alternative approach to total arterial revascularization, with multiple reports of superior long-term event-free outcome with its use. This extensive review of current literature reveals an absence of clear consensus as to what mix of conduits provides the best long-term outcomes. The quest for second best continues. Arterial conduits appear to be superior when grafted to tight stenosis but veins remain popular with surgeons. More supportive evidence from the concluding Arterial Revascularization trial and the Radial Artery Patency and Clinical Outcomes trial should guide future practice.

'Scoop and run' strategy for a resuscitative sternotomy following unstable penetrating chest injury.

The optimal management strategy of an unstable penetrating thoracic trauma remains a debate. It is unclear whether a 'stay and treat' or 'scoop and run' to the nearest operating theatre with cardiothoracic expertise is the best strategy. We describe a successful outcome of a young patient with injuries to the left internal mammary artery, upper lobe and main pulmonary artery following a stab injury to his left chest. He was transferred to the nearest cardiac centre for emergency sternotomy. Thoracotomy is the classical surgical approach in emergency setting but sternotomy allows adequate exposure to repair any cardiac injury, institution of cardiopulmonary bypass, and careful inspection of the mediastinal structures to prevent any late complications including pulmonary artery pseudoaneurysm. An immediate transfer, where possible, to the nearest trauma centre with cardiothoracic expertise for 'resuscitative' sternotomy is advocated in penetrating thoracic injury for optimal outcome. An emergency room thoracotomy should be reserved to those in the extremis.

Synergistic interaction between right ventricular mechanical dyssynchrony and pulmonary regurgitation determines early outcome following tetralogy of Fallot repair.

OBJECTIVE: The ability of the right ventricle to tolerate acute pulmonary regurgitation (PR) following tetralogy of Fallot (TOF) repair is variable and the mechanisms that underlie this are not completely understood. We hypothesise that dyssynchronous wall mechanics affects the RV tolerance to postoperative PR with adverse effect on early surgical outcome. METHODS: Twenty-four TOFs (mean age 19.5+/-15.5 months) undergoing elective repair were prospectively recruited. Ventricular wall mechanics was studied by tissue Doppler echocardiography following induction (preop) and postoperative day one (POD1) and compared with a control group (10 VSD/AVSD). Segmental dyssynchrony, defined as out-of-phase peak myocardial contraction, was determined at the base, mid, apical segments of the septum, RV and LV free walls and scored by the total number of affected segments. PR was graded from absent to severe and RV dimension was quantified by end-diastolic area index (RVEDAI). Cardiac index (CI) was measured by pulse contour cardiac output analysis. Outcome measures were CI, mixed venous oxygen saturation (SvO2), lactate, and duration of ventilation and critical care stay. RESULTS: Preoperatively, biventricular free-wall motion was synchronous in both groups. Following surgery, TOF developed RV-septal dyssynchrony (>2 segments in 11 (46%) vs none in control, p=0.01), while the LV free wall remained normal in both groups. RV-septal dyssynchrony correlated with the ventilation time (rho=0.69, p=0.003), critical care stay (rho=0.58, p=0.02) in the presence of PR (n=16), but not with other outcome measures. The relationships between dyssynchrony and early outcome were not seen when PR was absent. In the presence of PR, median RVEDAI was greater with higher dyssynchrony score (>3 segments; p=0.009). The degree of PR did not affect critical care/ventilation time or RVEDAI. The presence of transannular patch (p=0.007) or at least moderate PR (p=0.01) was associated with a more severe dyssynchrony. CONCLUSIONS: Dyssynchronous RV-septal wall mechanics occurs early after Fallot repair. The magnitude of dyssynchrony appears to interact synergistically with pulmonary regurgitation to influence RV dimension and early outcome.

The risk of fatal re-expansion pulmonary oedema in poor left ventricular reserve.

Re-expansion pulmonary oedema (REPO) is an uncommon complication which may be encountered following drainage of pneumothorax, pleural effusion or haemopneumothorax. Treatment is usually supportive and some patients may require positive pressure ventilation. We provide a novel description of the mechanism of a fatal REPO in a patient with a small and non-compliant left ventricle (LV). We urge for an extreme caution when performing thoracocentesis in patients with poor LV reserve.

Tissue Doppler imaging following paediatric cardiac surgery: early patterns of change and relationship to outcome.

In this study, tissue Doppler imaging (TDI) was used to assess changes in ventricular function following repair of congenital heart defects. The relationship between TDI indices, myocardial injury and clinical outcome was explored. Forty-five children were studied; 35 with cardiac lesions and 10 controls. TDI was performed preoperatively, on admission to paediatric intensive care unit (PICU) and day 1. Regional myocardial Doppler signals were acquired from the right ventricle (RV), left ventricle (LV) and septum. TDI indices included: peak systolic velocities, isovolumetric velocities (IVV) and isovolumetric acceleration (IVA). Preoperatively, bi-ventricular TDI velocities in the study group were reduced compared with normal controls. Postoperatively, RV velocities were significantly reduced and this persisted to day-1 (PreOp vs. PICU and day-1: 7.7+/-2.2 vs. 3.4+/-1.0, P<0.0001 and 3.55+/-1.29, P<0.0001). LV velocities initially declined but recovered towards baseline by day-1 (PreOp vs. PICU: 5.31+/-1.50 vs. 3.51+/-1.23, P<0.0001). Isovolumetric parameters in all regions were reduced throughout the postoperative period. Troponin-I release correlated with longer X-clamp times (r=0.82, P<0.0001) and reduced RV velocities (r=0.42, P=0.028). Reduced pre- and postoperative LV velocities correlated with longer ventilation (PreOp: r=0.54, P=0.002; PostOp: r=0.42, P=0.026). This study identified reduced postoperative RV velocities correlated with myocardial injury while reduced LV TDI correlated with longer postoperative ventilation.

Mediastinal irradiation and its effect on the cardiovascular system.

Mediastinal irradiation for various malignancies can cause radiation injury to mediastinal structures, most importantly the cardiovascular system. This article reviews the effect of radiation on cardiovascular structures and the manifestations of various radiation-induced heart diseases.

Septic arthritis of the manubriosternal joint.

Pyarthrosis of the manubriosternal joint is exceedingly rare. Its rarity defies an early diagnosis, and other causes of chest pain would normally be ruled out first. We describe a patient with a short history of chest pain, pyrexia, and raised inflammatory markers. A destroyed manubriosternal joint with a large abscess was found during surgical exploration. This case illustrates an unusually rapid development of septic arthritis involving a fibrocartilaginous joint in an otherwise healthy young man. Nine other cases have been described in the literature and are reviewed. Early diagnosis followed by adequate surgical drainage and antibiotic therapy led to a good outcome.

Ascending aortic origin of a branch pulmonary artery--surgical management and long-term outcome.

OBJECTIVE: Ascending aortic origin of a branch pulmonary artery (AOPA, hemitruncus arteriosus) is a rare congenital malformation. While there have been isolated case reports, larger series, relating to long-term outcomes following surgery are few. This article analyses the surgical results of a series of nine patients, over a period of 29 years. METHODS: Between 1974 and 2003, nine patients [neonates, 6; infants, 3; male, 5; female, 4] were operated on for AOPA. Median age at presentation was 14 days (range birth to 231 days). Six [corrected] patients (group 1) had associated simple lesions like patent ductus arteriosus or right aortic arch. Three patients (group 2) had complex lesions with right ventricular outflow tract obstruction. One patient (group 2) had DiGeorge syndrome. All patients except group 2 presented with congestive cardiac failure and, in addition one had pre-operative coronary ischemia. Diagnosis was established by angiocardiography in two patients and by echocardiography in seven [corrected] The median age at operation was 28 days (range 7-365). Follow-up period ranged from 7 months to 20.5 years (median 9 years). RESULTS: All nine patients had an anomalous right pulmonary artery (RPA) arising from the proximal ascending aorta, while the left branch was of right ventricular origin. All had evidence of pulmonary hypertension or elevated right ventricular pressure pre-operatively. There was no operative mortality. Of eight patients who had direct anastomosis of the RPA to the main pulmonary artery, one required patch enlargement and another required stenting of an anastomotic stenosis. One patient had a RV-RPA conduit, which required replacement 8, 13, and 14 years later. At follow-up, all patients were alive. All patients in group 1 had normal haemodynamic function and were in NYHA class I. In group 2, all were in NYHA class II with evidence of right ventricular hypertrophy. Four patients had post-operative ventilation-perfusion scans which showed satisfactory perfusion to both lungs. CONCLUSIONS: Early surgery is indicated in this lesion and is compatible with good long-term outlook. Surgical repair should not be deferred for corrective procedures of associated cardiac anomalies.