Repair of anomalous aortic origin of a coronary artery in 113 patients: a Congenital Heart Surgeons' Society report.

BACKGROUND: Anomalous aortic origin of a coronary artery (AAOCA) encompasses a wide morphologic spectrum, which has impeded consensus regarding indications for the diverse repair strategies. We constructed a profile of current surgical techniques and explore their application to morphologic variants. METHODS: Patients<30 years old (n=113) with isolated AAOCA who underwent operations at 29 Congenital Heart Surgeons Society (CHSS) institutions from 1998 to 2012 were identified from the CHSS AAOCA Registry. Operative findings were related to surgical techniques at index repairs by cross-tabulation. RESULTS: Anomalous origin of the left main or left anterior descending coronary artery was present in 33 (29%) patients and of the right coronary artery in 78 (69%) patients; 2 arteries originated directly above the commissure between the left and right sinuses. There were 101 (89%) interarterial and intramural (IA/IM) arteries, 10 (9%) were interarterial but not intramural (IA/NIM) and 2 (2%) were neither interarterial nor intramural. Intramural arteries were unroofed in 100 (88%) operations, usually with intimal tacking after incision (n=47) or excision (n=25) of the common wall. Coronary reimplantation (n=11), pulmonary artery relocation (n=7; 5 for IA/NIM), simple ostioplasty (without unroofing; n=3), coronary artery bypass grafting (n=2), and ostial window (n=1) were less common. In 37 (33%) operations, a valvar commissure was taken down; 33 were resuspended. CONCLUSION: Current surgical repair of AAOCA is individualized to morphology, particularly the presence of intramural and/or interarterial segments. This report is foundational for future planned CHSS studies that will examine interventional and noninterventional outcomes and ultimately guide management of AAOCA.

Glucocorticoids improve calcium cycling in cardiac myocytes after cardiopulmonary bypass.

BACKGROUND: Glucocorticoids can reduce myocardial dysfunction associated with ischemia and reperfusion injury following cardiopulmonary bypass (CPB) and circulatory arrest. The hypothesis was that maintenance of cardiac function after CPB with methylprednisolone therapy results, in part, from preservation of myocyte calcium cycling. METHODS: Piglets (5-7 kg) underwent CPB and 120 min of hypothermic circulatory arrest with (CPB-GC) or without (CPB) methylprednisolone (30 mgkg(-1)) administered 6h before and at CPB. Controls (No-CPB) did not undergo CPB or receive glucocorticoids (n=6 per treatment). Myocardial function was monitored in vivo for 120 min after CPB. Calcium cycling was analyzed using rapid line-scan confocal microscopy in isolated, fluo-3-AM-loaded cardiac myocytes. Phospholamban phosphorylation and sarco(endo)plasmic reticulum calcium-ATPase (SERCA2a) protein levels were determined by immunoblotting of myocardium collected 120 min after CPB. Calpain activation in myocardium was measured by fluorometric assay. RESULTS: Preload recruitable stroke work in vivo 120 min after reperfusion decreased from baseline in CPB (47.4±12 versus 26.4±8.3 slope of the regression line, P<0.05), but was not different in CPB-GC (41±8.1 versus 37.6±2.2, P=0.7). In myocytes isolated from piglets, total calcium transient time remained unaltered in CPB-GC (368±52.5 ms) compared with controls (434.5±35.3 ms; P=0.07), but was prolonged in CPB myocytes (632±83.4 ms; P<0.01). Calcium transient amplitude was blunted in myocytes from CPB (757±168 nM) compared with controls (1127±126 nM, P<0.05) but was maintained in CPB-GC (1021±155 nM, P>0.05). Activation of calpain after CPB was reduced with glucocorticoids. Phospholamban phosphorylation and SERCA2a protein levels in myocardium were decreased in CPB compared with No-CPB and CPB-GC (P<0.05). CONCLUSIONS: The glucocorticoid-mediated improvement in myocardial function after CPB might be due, in part, to prevention of calpain activation and maintenance of cardiac myocyte calcium cycling.

Improved current era outcomes in patients with heterotaxy syndromes.

OBJECTIVE: Patients with heterotaxy syndrome have a myriad of visceral and cardiac malformations historically resulting in significant morbidity and mortality. We sought to assess whether current era management strategies have improved outcomes in patients with visceral heterotaxy. METHODS: A retrospective review (1994-2008) of our database identified 45 consecutive heterotaxy patients who underwent surgical palliation. There were 29 patients with right atrial isomerism (RAI) and 16 patients with left atrial isomerism (LAI). Functional single ventricle was present in 32 patients. Pulmonary outflow obstruction was present in 29 of the patients. Twenty patients had total anomalous pulmonary venous return (TAPVR), of which 9 were obstructed. An initial neonatal surgical approach was performed in 27 patients. Thirty patients had systemic to pulmonary artery shunt. Mean follow-up was 43.6+/-47 months in RAI and 41.0+/-40.8 months in LAI patients (p=0.4). RESULTS: There were three hospital deaths, all after the first operation, and four interstage deaths (six RAI; one LAI). There were no deaths after cavopulmonary shunt, Kawashima or Fontan operation. A multivariate Cox regression identified greater than moderate atrioventricular valve regurgitation (Hazard Ratio (HR) 17.5, p=0.017) and obstructed TAPVR (HR 17.5, p=0.007) as factors associated with increased RAI mortality. Due to the absence of late mortality in both groups, patient survival at 3 years were 79% in RAI and 94% in LAI patients and remained stable after that (p=0.22). All survivors but one are in NYHA class I or II, without significant cardiovascular related symptoms. LAI patients have a higher incidence of sinus node dysfunction than RAI patients (47% vs 12.5%, p=0.009). CONCLUSIONS: Surgical outcomes in heterotaxy patients are improving in the current era. The risk for operative mortality and attrition is highest between the first and second stage palliation procedures. Significant atrioventricular valve regurgitation and obstructed TAPVR remain risk factors for RAI mortality. Survivors are doing well with no activity restrictions, although LAI patients maintain a higher proclivity of sinus node dysfunction.

Modulation of nuclear factor-kappaB improves cardiac dysfunction associated with cardiopulmonary bypass and deep hypothermic circulatory arrest.

OBJECTIVE: The hypothesis is that partial nuclear factor-kappaB (NF-kappaB) inhibition can alleviate cardiopulmonary dysfunction associated with ischemia and reperfusion injury following cardiopulmonary bypass and deep hypothermic circulatory arrest (CPB/DHCA) in a pediatric model. DESIGN: Animal case study. SUBJECTS: Two-week-old piglets (5-7 kg). INTERVENTIONS: Piglets received 100 microg/kg of SN50, a peptide inhibitor of NF-kappaB translocation and activation, 1 hour before CPB. The control group received saline. Animals were cooled to 18 degrees C with CPB, the piglets were in DHCA for 120 minutes, and the piglets were then rewarmed on CPB to 38 degrees C and maintained for 120 minutes after CPB/DHCA. MEASUREMENTS: Sonomicrometry and pressure catheters collected hemodynamic data. Transmural left and right ventricular tissues were obtained at the terminal time point for determination of NF-kappaB activity by enzyme-linked immunosorbent assay. Data are expressed as mean +/- sd. MAIN POINTS: Oxygen delivery was maintained at 76 +/- 13 mL/min at baseline and 75 +/- 5 mL/min at 120 minutes after CPB/DHCA (p = 0.75) in SN50-treated animals vs. 99 +/- 26 mL/min at baseline and 63 +/- 20 mL/min at 120 minutes in the untreated group (p = 0.0001). Pulmonary vascular resistance (dynes.sec.cm) increased from 124 +/- 59 at baseline to 369 +/- 104 at 120 minutes in the untreated piglets (p = 0.001) compared with SN50-treated animals (100 +/- 24 at baseline and 169 +/- 88 at 120 minutes, p = 0.1). NF-kappaB activity was reduced by 74% in left ventricles of SN50-treated compared with SN50-untreated animals (p < 0.001). Plasma endothelin-1 (pg/mL), an important vasoconstrictor regulated by NF-kappaB, increased from 2.1 +/- 0.4 to 14.2 +/- 5.7 in untreated animals (p = 0.004) but was elevated to only 4.5 +/- 2 with SN50 treatment (p = 0.005). CONCLUSIONS: Improvement of cardiopulmonary function after ischemia/reperfusion was associated with the reduction of NF-kappaB activity in piglet hearts. Maintenance of systemic oxygen delivery and alleviation of pulmonary hypertension after CPB/DHCA in piglets administered SN50, possibly through a reduction of circulating endothelin-1, suggest that selective inhibition of NF-kappaB activity may reduce ischemia and reperfusion injury after pediatric cardiac surgery.

Computed tomographic appearance of Prolene Hernia System and polypropylene mesh plug inguinal hernia repair.

PURPOSE: To describe the normal postoperative computed tomographic (CT) appearance of inguinal hernia repair with the Prolene (polypropylene) Hernia System and polypropylene mesh plug. MATERIALS AND METHODS: The medical records for 480 consecutive patients who underwent inguinal mesh hernioplasty were reviewed to identify posthernioplasty pelvic CT scans. The presence or absence of the appearance and size of focal inguinal findings at CT for each groin was recorded by 2 radiologists in consensus. The CT scan reports and medical records were reviewed to determine prospective interpretations of these inguinal findings. FINDINGS: Posthernoplasty CT scans were identified in 26 patients, of whom, 20 had Prolene Hernia System (unilateral, n = 20; bilateral, n = 1) or mesh plug (unilateral, n = 5; bilateral, n = 1) repairs. These patients consisted of 23 men and 3 women with a mean age of 63 years (range, 36-89 years). For Prolene Hernia System hernioplasty patients, ipsilateral focal inguinal findings were found at CT in 21 of 22 groins. These focal findings had a mean size of 2.6 +/- 0.4 by 2.0 +/- 0.5 cm and were ringlike in 9, nodular in 7, and feathery in appearance in 5 groins. For mesh-plug hernioplasty, ipsilateral nodular focal inguinal findings were found in all 6 of 6 groins at CT. In 2 patients, nodular focal inguinal findings were mistaken for lymphadenopathy on the prospective CT report. CONCLUSION: Focal inguinal findings from mesh plug inguinal hernioplasty are common, have characteristic appearances at CT, and should not be mistaken as lymphadenopathy.

Acute beta-blockade prevents myocardial beta-adrenergic receptor desensitization and preserves early ventricular function after brain death.

OBJECTIVE: Beta-adrenergic receptor desensitization through activation of the G protein-coupled receptor kinase 2 is an important mechanism of early cardiac dysfunction after brain death. We hypothesized that acute beta-blockade can prevent myocardial beta-adrenergic receptor desensitization after brain death through attenuation of G protein-coupled receptor kinase 2 activity, resulting in improved cardiac function. METHODS: Adult pigs underwent either sham operation, induction of brain death, or treatment with esmolol (beta-blockade) for 30 minutes before and 45 minutes after brain death (n = 8 per group). Cardiac function was assessed at baseline and for 6 hours after the operation. Myocardial beta-adrenergic receptor signaling was assessed 6 hours after operation by measuring sarcolemmal membrane adenylate cyclase activity, beta-adrenergic receptor density, and G protein-coupled receptor kinase 2 expression and activity. RESULTS: Baseline left ventricular preload recruitable stroke work was similar among sham, brain death, and beta-blockade groups. Preload recruitable stroke work was significantly decreased 6 hours after brain death versus sham, and beta-blockade resulted in maintenance of baseline preload recruitable stroke work relative to brain death and not different from sham. Basal and isoproterenol-stimulated adenylate cyclase activities were preserved in the beta-blockade group relative to the brain death group and were not different from the sham group. Left ventricular G protein-coupled receptor kinase 2 expression and activity in the beta-blockade group were markedly decreased relative to the brain death group and similar to the sham group. Beta-adrenergic receptor density was not different among groups. CONCLUSION: Acute beta-blockade before brain death attenuates beta-adrenergic receptor desensitization mediated by G protein-coupled receptor kinase 2 and preserves early cardiac function after brain death. These data support the hypothesis that acute beta-adrenergic receptor desensitization is an important mechanism in early ventricular dysfunction after brain death. Future studies with beta-blocker therapy immediately after brain death appear warranted.

Factors affecting long-term risk of aortic arch recoarctation after the Norwood procedure.

BACKGROUND: The purpose of this study was to identify factors predicting risk of aortic arch recoarctation after the Norwood procedure. METHODS: Patient records were reviewed retrospectively for consecutive patients who underwent the Norwood procedure from 1996 to 2005. Preoperative and intraoperative parameters were identified for analysis. Aortic arch recoarctation was defined by the need for catheter or surgical reintervention. Data were analyzed using survival analysis, with freedom from intervention as the outcome. Factors predicting need for reintervention were analyzed using Cox proportional hazards regression. RESULTS: Thirty-five recoarctations were observed in 117 patients (30%). Freedom from aortic arch reintervention at six months, one, three, and five years were 72%, 63%, 56%, and 52%, respectively. The majority of arch reinterventions occurred in the first six months (63%), involving either surgical (43%) or catheter (57%) techniques. The use of bovine pericardium showed the greatest risk for potential recoarctation (hazard ratio = 1.81 [0.90-3.64], p = 0.09). Age, gender, weight, ascending aortic diameter, ventricular morphology, primary anatomic diagnosis, and coarctation shelf resection were not found to be predictors of recoarctation. CONCLUSIONS: Most interventions for aortic arch recoarctation after the Norwood procedure occur within the first six months of life. The type of patch material used for arch reconstruction appears to influence, most strongly, the long-term risk of aortic arch recoarctation.

Beta-adrenergic receptor antagonism preserves myocardial function after brain death in a porcine model.

BACKGROUND: Cardiac dysfunction after brain death decreases the already limited number of potential donors for cardiac transplantation. Acute beta-adrenergic receptor (betaAR) desensitization after the brain death-associated catecholamine surge is an important mechanism. We hypothesized that acute betaAR antagonism could improve myocardial function after brain death by preserving betaAR signaling. METHODS: Pigs were randomly assigned to three study groups (n = 5): sham; brain death; and brain death with betaAR antagonist (200 microg/kg/min esmolol), 30 minutes before brain death until 45 minutes after brain death. Functional data were collected for 6 hours after brain death and tissues procured. RESULTS: Compared with baseline, pre-load recruitable stroke work (PRSW), a pre-load-independent measure of systolic function (21.4 +/- 7.5 vs 43.3 +/- 6.8, slope of regression line during vena caval occlusion, p < 0.001), diastolic function (Tau, 101 +/- 54.7 vs 36.4 +/- 5.4 ms, p = 0.03) and systemic oxygen delivery (151 +/- 79.7 vs 298 +/- 78.7 ml/min, p < 0.001) deteriorated in untreated animals at 6 hours after brain death. In contrast, betaAR antagonist maintained baseline systolic function (PRSW, 37.8 +/- 5.6 vs 38.2 +/- 4.7, slope of regression line during vena caval occlusion, p = 0.92), diastolic function (Tau, 32.6 +/- 5.1 vs 48.5 +/- 28.3 ms, p = 0.57) and oxygen delivery (427 +/- 116 vs 397 +/- 98.8 ml/min, p = 0.36) at 6 hours after brain death. betaAR antagonist preserved betaAR signaling, as demonstrated by similar left ventricular (LV) basal (55.4 +/- 32.8 vs 58.8 +/- 10.9 pmol/mg/min, p = 0.40) and isoproterenol-stimulated (125 +/- 70.5 vs 124 +/- 52.0 pmol/mg/min, p = 0.49) adenylate cyclase activity at 6 hours after brain death, upon comparing betaAR antagonist and sham treatment groups. Both LV basal and isoproterenol-stimulated adenyl cyclase activity were higher with betaAR antagonist (25.9 +/- 4.8 pmol/mg/min, p = 0.03) than with untreated brain death (55.6 +/- 17.3 pmol/mg/min, p = 0.02). CONCLUSIONS: Beta-adrenergic receptor antagonism before brain death preserves cardiac function by preventing betaAR desensitization. This therapy in potential donors might increase the number of organs available for transplantation.

Glucocorticoids alter the balance between pro- and anti-inflammatory mediators in the myocardium in a porcine model of brain death.

BACKGROUND: Cardiac dysfunction after brain death (BD) limits donors for cardiac transplantation. Glucocorticoids ameliorate brain death-induced donor heart dysfunction. We hypothesized that glucocorticoid therapy alleviates myocardial depression through altering the balance between pro- and anti-inflammatory mediators via the nuclear factor-kappaB (NF-kappaB)/inhibitor of kappaB-alpha (IkappaBalpha) pathway and/or by preserving beta-adrenergic receptor (betaAR) signaling in the heart. METHODS: Crossbred pigs (25 to 35 kg) were randomly assigned to the following groups (n = 5/treatment): sham (Group 1); BD (Group 2); and BD with glucocorticoids (30 mg/kg methylprednisolone), either 2 hours before (Group 3) or 1 hour after BD (Group 4). Tumor necrosis factor-alpha (TNF-alpha) levels were measured in plasma at baseline and 1 hour and 6 hours after BD. Protein levels were measured in left ventricular homogenates procured 6 hours after BD. RESULTS: Pro-inflammatory proteins (TNF-alpha) and interleukin-6 were lower in Group 3 and Group 4 compared with Group 2 at 6 hours after BD (p < 0.01). Intracellular adhesion molecule-1 was also lower in Group 4 compared with Group 2 (p = 0.001). Interleukin-10, an anti-inflammatory mediator, was lower in Group 4 than in Group 2 (p < 0.001), but not different between Groups 2 and 3. At 6 hours after BD, neither NF-kappaB activity nor basal adenylate cyclase activity differed between Groups 3 and 4 compared with Group 2. CONCLUSIONS: Glucocorticoids maintained myocardial function and shifted the balance of pro- and anti-inflammatory mediators after BD. The mechanisms by which glucocorticoids preserve myocardial function, however, do not appear to involve the NF-kappaB pathway or betaAR signaling.

Pulmonary atresia with intact ventricular septum: initial management.

BACKGROUND: Outcomes for pulmonary atresia with intact ventricular septum are suboptimal, while initial management remains controversial. This study was undertaken to determine the effect of catheter-based therapy on the need for early surgical intervention. METHODS: A single-institution retrospective chart review was made of all 25 neonates with pulmonary atresia with intact ventricular septum from 1999 to 2005. RESULTS: Mean age at first intervention was 3.1 +/- 2.2 days, mean weight 3.3 +/- 0.5 kg. Right ventricular hypoplasia varied: 20% normal, 16% mild, 28% moderate, 28% moderately severe or severe, 8% not classified. Median tricuspid valve z-score was -2.3 +/- 2.6. First intervention was catheter-based therapy in 56% (14 of 25), operative in 36% (9 of 25), and no therapy in 2. Technically adequate valvotomy was achieved in 79% (11 of 14). Serious catheter-related complications occurred in 3 of 14 (21%). Only 5 of 14 (36%) with catheter-based therapy weaned from prostaglandins without surgery. Of these, 2 required surgery for cyanosis at 1 and 3 months. Surgery after catheter-based therapy consisted of right ventricular outflow patch in 36% (4 of 11), systemic to pulmonary shunt in 64% (7 of 11). Median time between catheter-based therapy and surgery was 8.5 days (range, 1 to 89). Only 3 of the 23 treated patients avoided operation during infancy. There was 1 early and 1 late death after operation after initial catheter-based therapy, and 1 late death after primary surgery alone during a mean follow-up of 33 months (range, 1.5 to 79). CONCLUSIONS: Balloon valvotomy alone for pulmonary atresia with intact ventricular septum rarely obviates the need for an additional source of pulmonary blood flow--either shunt or ductal stenting.

Bilateral semilunar valve disease in a child with partial deletion of the Williams-Beuren syndrome region is associated with elastin haploinsufficiency.

Elastin is an extracellular matrix protein that is the primary component of elastic fibers, and is expressed in the great vessels as well as the semilunar and atrioventricular valves. Elastin haploinsufficiency, resulting from mutation or deletion of the elastin gene, is an important clinical problem that is typically characterized by arteriopathy. Herein is described a patient with elastin haploinsufficiency due to partial deletion of the Williams-Beuren syndrome region, resulting in bilateral semilunar valve disease and arteriopathy. Histochemical analysis of the aortic valve revealed decreased and disorganized elastin with loss of the normal trilaminar cusp organization. These findings suggest that elastin has a role in the pathogenesis of semilunar valve disease.

Current treatments for congenital aortic stenosis.

PURPOSE OF REVIEW: Congenital valvar aortic stenosis is a challenging disease that often requires repeated palliative procedures. Stenosis can range from mild and asymptomatic, not requiring intervention, to severe, as seen in hypoplastic left heart syndrome. New advances such as fetal balloon valvuloplasty, improvements in the Ross technique, and long-term studies of trans-catheter balloon valvuloplasty and surgical valvotomy warrant a review of the outcomes and optimal timing of the various interventions. RECENT FINDINGS: Fetal balloon valvuloplasty has shown promise. Despite some mortality and morbidity, some fetuses are showing significant growth in left ventricular structures, allowing biventricular repair. In neonates and infants with congenital aortic stenosis, excellent initial results are obtained with trans-catheter balloon valvuloplasty, although stenosis resistant to further balloon dilation or regurgitation may develop, necessitating surgical intervention. Midterm results from the Ross procedure are encouraging, demonstrating low rates of mortality, aortic insufficiency and re-intervention. Stenosis of the pulmonary allograft may be inevitable, and recent long-term follow-up suggests an increase in aortic insufficiency. SUMMARY: While availability of fetal balloon valvuloplasty is limited, it has promise for promoting in-utero left ventricle growth and improving function. The optimal procedure for infants and neonates is trans-catheter balloon valvuloplasty. For older patients, the Ross procedure is the repair of choice, although more long-term studies are needed to assess the natural course of the autograft. Outcomes should improve with advances in pulmonary allografts.

Brain magnetic resonance imaging abnormalities after the Norwood procedure using regional cerebral perfusion.

OBJECTIVES: Neurologic deficits are common after the Norwood procedure for hypoplastic left heart syndrome. Because of the association of deep hypothermic circulatory arrest with adverse neurologic outcome, regional low-flow cerebral perfusion has been used to limit the period of intraoperative brain ischemia. To evaluate the impact of this technique on brain ischemia, we performed serial brain magnetic resonance imaging in a cohort of infants before and after the Norwood operation using regional cerebral perfusion. METHODS: Twenty-two term neonates with hypoplastic left heart syndrome were studied with brain magnetic resonance imaging before and at a median of 9.5 days after the Norwood operation. Results were compared with preoperative, intraoperative, and postoperative risk factors to identify predictors of neurologic injury. RESULTS: Preoperative magnetic resonance imaging (n = 22) demonstrated ischemic lesions in 23% of patients. Postoperative magnetic resonance imaging (n = 15) demonstrated new or worsened ischemic lesions in 73% of patients, with periventricular leukomalacia and focal ischemic lesions occurring most commonly. Prolonged low postoperative cerebral oximetry (<45% for >180 minutes) was associated with the development of new or worsened ischemia on postoperative magnetic resonance imaging (P = .029). CONCLUSIONS: Ischemic lesions occur commonly in neonates with hypoplastic left heart syndrome before surgery. Despite the adoption of regional cerebral perfusion, postoperative cerebral ischemic lesions are frequent, occurring in the majority of infants after the Norwood operation. Long-term follow-up is necessary to assess the functional impact of these lesions.

Heparin-induced thrombocytopenia complicating support by the Berlin Heart.

Since 1992, miniaturized pulsatile air-driven ventricular assist devices (VADs), "Berlin Heart," have been used at many institutions (36 cases in North America in 19 different institutions) for pediatric use. Heparin-induced thrombocytopenia (HIT II) is a significant complication rarely reported in the setting of adult VAD support; no similar report exists concerning pediatric VAD support. We report on a 13-month-old, 8.1 kg girl who required LVAD support for cardiogenic shock of unclear etiology. The patient had a history of multiple surgical repairs for correction of complex congenital heart disease consisting of a series of left heart obstructive lesions (Shone's complex). Despite aggressive ventilatory and inotropic support, the patient continued to deteriorate and subsequently required extracorporeal life support. After 7 days of conventional venoarterial extracorporeal membrane oxygenation, a 10 ml Berlin Heart VAD was implanted. After implantation, the patient developed persistent low-grade fever of unclear etiology, gradual thrombocytopenia, and deterioration of renal function. On postimplant day 10, the pump required replacement because of concerns about an inlet valve thrombus; the explanted device demonstrated a nearly occlusive clot not appreciable from external inspection. Simultaneously, HIT II was diagnosed as a result of hematology workup for persistent thrombocytopenia. We discuss the unique challenges posed by HIT II complicating pediatric VAD support and in relation to the heparin coating of the device.

Glucocorticoid administration reduces cardiac dysfunction after brain death in pigs.

BACKGROUND: Traumatic brain injury and subsequent brain death (BD) account for nearly half of all organ donors, yet only 33% of available hearts are transplanted. Alterations in multiple physiologic pathways after BD can lead to cardiac dysfunction and exclusion from transplantation. Triple hormone resuscitation with methylprednisolone, thyroid hormone and vasopressin has had inconsistent results in the effort to reduce cardiac dysfunction associated with BD, but individual analysis of these agents is limited. The hypothesis was that glucocorticoid administration alone could reduce BD-associated cardiac dysfunction. METHODS: Crossbred pigs (25 to 35 kg) had BD induced by sub-dural balloon inflation. Hemodynamics were measured for 360 minutes after BD. Negative cerebral perfusion pressures and decreased laser Doppler cerebral blood flow confirmed BD. Animals (n = 5/treatment group) received: saline (Group 1); 30 mg/kg methylprednisolone 2 hours before BD (Group 2); or 30 mg/kg methylprednisolone 1 hour after BD (Group 3). Repeated measures analysis of variance and unpaired t-tests were used for appropriate comparisons. RESULTS: Left ventricular (LV) pre-load recruitable stroke work (PRSW) decreased in untreated Group 1 over time (p < 0.001), whereas PRSW in animals treated with glucocorticoids, Groups 2 and 3, was not different from baseline at 360 minutes after BD. Diastolic function measured as LV -dP/dt (minimum derivative of the change in pressure over time) and tau (time constant of isovolumic relaxation) was also preserved 360 minutes after brain death by glucocorticoids in Groups 2 and 3 (p > 0.05). Oxygen delivery 360 minutes after BD was higher in Group 2 compared with Group 1 (p = 0.02) and Group 3 (p = 0.006). CONCLUSIONS: Glucocorticoid therapy before or after BD preserved LV systolic and diastolic function. Glucocorticoids administered after brain death might increase the number of hearts available for transplant by reducing brain death-associated cardiac dysfunction.

Brain magnetic resonance imaging abnormalities after the Norwood procedure using regional cerebral perfusion.

OBJECTIVES: Neurologic deficits are common after the Norwood procedure for hypoplastic left heart syndrome. Because of the association of deep hypothermic circulatory arrest with adverse neurologic outcome, regional low-flow cerebral perfusion has been used to limit the period of intraoperative brain ischemia. To evaluate the effect of this technique on brain ischemia, we performed serial brain magnetic resonance imaging in a cohort of infants before and after the Norwood operation using regional cerebral perfusion. METHODS: Twenty-two term neonates with hypoplastic left heart syndrome were studied with brain magnetic resonance imaging before and at a median of 9.5 days after the Norwood operation. Results were compared with preoperative, intraoperative, and postoperative risk factors to identify predictors of neurologic injury. RESULTS: Preoperative magnetic resonance imaging (n = 22) demonstrated ischemic lesions in 23% of patients. Postoperative magnetic resonance imaging (n = 15) demonstrated new or worsened ischemic lesions in 73% of patients, with periventricular leukomalacia and focal ischemic lesions occurring most commonly. Prolonged low postoperative cerebral oximetry (<45% for >180 minutes) was associated with the development of new or worsened ischemia on postoperative magnetic resonance imaging (P = .029). CONCLUSIONS: Ischemic lesions occur commonly in neonates with hypoplastic left heart syndrome before surgical intervention. Despite the adoption of regional cerebral perfusion, postoperative cerebral ischemic lesions are frequent, occurring in the majority of infants after the Norwood operation. Long-term follow-up is necessary to assess the functional effect of these lesions.

Role of the beta-adrenergic receptor kinase in myocardial dysfunction after brain death.

OBJECTIVE: Significant cardiac dysfunction after brain death leading to exclusion from procurement for cardiac transplantation is seen in up to 25% of potential organ donors in the absence of structural heart disease. The cause includes uncoupling of the myocardial beta-adrenergic receptor signaling system. The mechanism, however, has not yet been described. This study investigates our hypothesis that brain death causes acute activation of the betaAR kinase and leads to desensitization of myocardial beta-adrenergic receptors and impaired ventricular function. METHODS: Adult pigs underwent a sham operation or induction of brain death by means of subdural balloon inflation (n = 8 in each group). Cardiac function was assessed by using sonomicrometry at baseline and for 6 hours after the operation. beta-Adrenergic receptor signaling was assessed at 6 hours after the operation by measuring myocardial sarcolemmal membrane adenylate cyclase activity, beta-adrenergic receptor density, beta-adrenergic receptor kinase expression, and activity. RESULTS: Induction of brain death led to significantly decreased left ventricular systolic and diastolic function. Basal and isoproterenol-stimulated adenylate cyclase activity was blunted in the brain dead group compared with the sham-operated group (28.3 +/- 4.3 vs 48.3 +/- 7.6 pmol of cyclic adenosine monophosphate.mg(-1) x min(-1) [P = .01] and 54.8 +/- 9.6 vs 114.5 +/- 18 pmol of cyclic adenosine monophosphate x mg(-1) x min(-1) [P < .02]). There was no difference in beta-adrenergic receptor density between the brain dead and sham-operated groups. Myocardial beta-adrenergic receptor kinase expression was 3-fold greater in the brain dead versus sham-operated groups, and membrane beta-adrenergic receptor kinase activity was 2.5-fold greater in the brain dead group compared with that seen in the sham-operated group. CONCLUSION: Induction of brain death leads to significant left ventricular dysfunction in this porcine model. Cardiac beta-adrenergic receptors are clearly uncoupled after brain death, and our data suggest that the mechanism is acute increase of myocardial beta-adrenergic receptor kinase activity, leading to beta-adrenergic receptor desensitization and ventricular dysfunction.

Inhibition of p38 reduces myocardial infarction injury in the mouse but not pig after ischemia-reperfusion.

The MAPK family member p38 is activated in the heart after ischemia-reperfusion (I/R) injury. However, the cardioprotective vs. proapoptotic effects associated with p38 activation in the heart after I/R injury remain unresolved. Another issue to consider is that the majority of past studies have employed the rodent as a model for assessing p38's role in cardiac injury vs. protection, while the potential regulatory role in a large animal model is even more uncertain. Here we performed a parallel study in the mouse and pig to directly compare the extent of cardiac injury after I/R at baseline or with the selective p38 inhibitor SB-239063. Infusion of SB-239063 5 min before ischemia in the mouse prevented ischemia-induced p38 activation, resulting in a 25% reduction of infarct size compared with vehicle-treated animals (27.9 +/- 2.9% vs. 37.5 +/- 2.7%). In the pig, SB-239063 similarly inhibited myocardial p38 activation, but there was no corresponding effect on the degree of infarction injury (43.6 +/- 4.0% vs. 41.4 +/- 4.3%). These data suggest a difference in myocardial responsiveness to I/R between the small animal mouse model and the large animal pig model, such that p38 activation in the mouse contributes to acute cellular injury and death, while the same activation in pig has no causative effect on these parameters.

Calpain inhibition decreases endothelin-1 levels and pulmonary hypertension after cardiopulmonary bypass with deep hypothermic circulatory arrest.

OBJECTIVE: Cardiopulmonary bypass in infants and children can result in cardiopulmonary dysfunction through ischemia and reperfusion injury. Pulmonary hypertension and injury are particularly common and morbid complications of neonatal cardiac surgery. Inhibition of calpain, a cysteine protease, has been shown to inhibit reperfusion injury in adult organ systems. The hypothesis is that calpain inhibition can alleviate the cardiopulmonary dysfunction seen in immature animals following ischemia and reperfusion with cardiopulmonary bypass. DESIGN: Animal case study. SETTING: Medical laboratory. SUBJECTS: Crossbred piglets (5-7 kg). INTERVENTIONS: Piglets were cooled with cardiopulmonary bypass to 18 degrees C followed by deep hypothermic circulatory arrest for 120 mins. Animals were rewarmed to 38 degrees C on cardiopulmonary bypass and maintained for 120 mins. Six animals were administered calpain inhibitor (Z-Leu-Leu-Tyr-fluoromethyl ketone; 1 mg/kg, intravenously) 60 mins before cardiopulmonary bypass. Nine animals were administered saline as a control. Plasma endothelin-1, pulmonary and hemodynamic function, and markers of leukocyte activity and injury were measured. MEASUREMENTS AND MAIN RESULTS: Calpain inhibition prevented the increased pulmonary vascular resistance seen in control animals (95.7 +/- 39.4 vs. 325.3 +/- 83.6 dyne.sec/cm, respectively, 120 mins after cardiopulmonary bypass and deep hypothermic circulatory arrest, p = .05). The attenuation in pulmonary vascular resistance was associated with a blunted plasma endothelin-1 response (4.91 +/- 1.72 pg/mL with calpain inhibition vs. 10.66 +/- 6.21 pg/mL in controls, p < .05). Pulmonary function after cardiopulmonary bypass was better maintained after calpain inhibition compared with controls: Po2/Fio2 ratio (507.2 +/- 46.5 vs. 344.7 +/- 140.5, respectively, p < .05) and alveolar-arterial gradient (40.0 +/- 17.2 vs. 128.1 +/- 85.2 mm Hg, respectively, p < .05). Systemic oxygen delivery was higher after calpain inhibition compared with controls (759 +/- 171 vs. 277 +/- 46 mL/min, respectively, p < .001). In addition, endothelial nitric oxide synthase activity in lung tissue was maintained with calpain inhibition. CONCLUSIONS: The reduction in plasma endothelin-1 and maintenance of lung endothelial nitric oxide levels after cardiopulmonary bypass and deep hypothermic circulatory arrest with calpain inhibition were associated with reduced pulmonary vascular resistance. Improved gas exchange and higher systemic oxygen delivery suggest that calpain inhibition may be advantageous for reducing postoperative cardiopulmonary dysfunction commonly associated with pediatric heart surgery and cardiopulmonary bypass.