[Supra-annular Mitral Valve Replacement Using a Composite Valve for an Infant with Acute Rupture of Chordae Tendineae].

Acute rupture of the chordae tendineae of the mitral valve could lead to severe mitral regurgitation and circulatory collapse in infants. Mitral valve replacement may be often challenging because of the valve-annulus size mismatch in small infants when mitral valve repair cannot be accomplished. We present an infant with acute massive rupture of the chordae tendineae of the mitral valve who successfully underwent supra-annular mitral valve replacement using the short composite valve of an expanded polytetrafluoroethylene( ePTFE) graft and a mechanical valve. His mechanical valve has been functioning without complications such as thrombosis and pulmonary venous obstruction for 20 months after surgery. This technique could be helpful even infants with acute rupture of the chordae tendineae of the mitral valve whose left atrium may not be dilated.

A Case of Successful Biventricular Repair of the Transposition of the Great Arteries with a Coronary Anomaly Associated with an Atrioventricular Septal Defect.

The transposition of the great arteries (TGA) associated with a complete atrioventricular septal defect is a rare and serious congenital cardiac anomaly. In this report, we describe the successful biventricular repair of a TGA with a complete atrioventricular septal defect in an infant. Due to the low body weight of the patient and a complex coronary pattern anomaly, an arterial switch operation was executed, with the Mee procedure and pulmonary arterial banding as initial palliative measures when the infant was 22 days old and weighed 2.5 kg. Subsequently, atrioventricular septal defect repair using the modified one-patch method was performed when the patient was 1.3 years old and weighed 8.8 kg. Remarkably, the postoperative course of the patient demonstrated no notable incidents. To our knowledge, this is the first time a two-stage strategy was applied to repair these complex defects, presenting a promising approach for managing similar cases in future medical practice.

Late bacterial endocarditis after percutaneous atrial septal defect closure.

Percutaneous atrial septal defect closure is widely used as an alternative to surgical repair in many hospitals. Infective endocarditis related to occluding devices is commonly known, but following that atrial septal defect closure with a device in a child is rare. This report describes an 11-year-old girl who developed late-stage bacterial endocarditis following incomplete endothelialisation after a percutaneous procedure.

The Lymphatic Circulation in Adaptations to the Fontan Circulation.

Failing Fontan continues to be major problem for patients on the univentricular pathway. Failing Fontan is often complicated by chylothorax, plastic bronchitis and protein loosing enteropathy. The role of lymphatic circulation in Fontan circulation is still being researched. Newer imaging modalities give insight into the role of abnormal dilatation and retrograde flow in lymphatic channels post Fontan. Interventional strategies targeting abnormal lymphatic channels, provides an alternative management strategy for patients with failing Fontan. This review focuses on the role of lymphatic system in adaptations to Fontan circulation.

An increased incidence of conduit endocarditis in patients receiving bovine jugular vein grafts compared to cryopreserved homograft for right ventricular outflow reconstruction.

BACKGROUND: We compared the outcome of patients receiving bovine jugular vein grafts versus cryopreserved homografts for right ventricular outflow tract reconstruction. METHODS: Between 2000 and 2012, 379 conduits (244 bovine jugular vein grafts, 135 homografts) were implanted in 298 patients (median age 50 months) with a median follow-up of 3.4 years. RESULTS: Freedom from reoperation at 1, 5, and 7 years was 96.3%, 79.3%, and 64.2% after bovine jugular vein graft and 94.6%, 75.7%, and 68.6% after homograft insertion (p = 0.086). There were 24 cases of endocarditis, 23 associated with bovine jugular vein grafts (9.4%) and 1 associated with a homograft (0.7%; p < 0.001) at median follow-up of 44 months (range, 15 days to 10 years) after conduit implantation. After endocarditis, 15 of 24 conduits were replaced. Three patients had recurrent endocarditis in the revised conduit. Multivariate logistic regression analysis showed age less than 3 years and endocarditis to be significant risk factors associated with conduit replacement. Age more than 3 years and bovine jugular vein grafts were significant risk factors for graft endocarditis. Patients more than 3 years of age at bovine jugular vein graft implantation had significantly lower freedom from reoperation (p = 0.01). CONCLUSIONS: Compared with homograft conduits, the use of bovine jugular vein grafts for right ventricular outflow tract reconstruction was associated with a significantly higher incidence of bacterial endocarditis and conduit deterioration in older children at our institution. That may influence decision making regarding conduit choice for right ventricular outflow tract reconstruction. Patients and practitioners should be aware of the late risks of bacterial endocarditis after bovine jugular vein graft implantation.

Modified single-patch compared with two-patch repair of complete atrioventricular septal defect.

BACKGROUND: We compared the outcomes of modified single-patch and two-patch surgical repair of complete atrioventricular septal defect (CAVSD) on left ventricular outflow tract (LVOT) diameter and on left atrioventricular valve (LAVV) coaptation. METHODS: We reviewed retrospectively postoperative 2-dimensional echocardiograms of all CAVSD patients who underwent modified single-patch or two-patch repair between 2005 and 2011. We measured the leaflet coaptation length of the LAVV in the apical four-chamber view. The LVOT was measured in the long axis view. RESULTS: Fifty-one patients underwent CAVSD repair at a median age of 4 months (range, 1 to 9 months) (single-patch, n=29; two-patch, n=22). The images from 46 echocardiograms were adequate for analysis. Modified single-patch repair required significantly shorter bypass time (102.0±33.6 vs 152.9±39.5 minutes, p<0.001) and ischemic time (69.0±21.7 vs 106.9±29.7 minutes, p<0.001) than did two-patch repair. The indexed coaptation length of the septal and lateral leaflets was not different between single-patch and two-patch (3.1±2.3 vs 4.1±3.1 mm/m2, p=0.25; 2.3±2.3 vs 3.3±3.0 mm/m2, p=0.21). Indexed LVOT diameter was not different in the two groups (26.1±5.2 vs 28.5±7.1 mm/m2, p=0.22). There was no hospital or late death during the median follow-up time of 35 months (range, 1 to 69 months). Five patients underwent reoperation after single-patch repair (3 with residual ventricular septal defect [VSD] and LAVV regurgitation, 1 with residual VSD, 1 with pacemaker implantation). After the two-patch repair, 1 patient required reoperation for a residual VSD and right atrioventricular valve regurgitation (p=0.22). CONCLUSIONS: The modified single-patch repair was performed with significantly shorter bypass time and myocardial ischemic time. The postoperative LVOT diameter and LAVV leaflet coaptation length were not significantly different between techniques.

Right ventricular and tricuspid valve remodeling after bidirectional cavopulmonary anastomosis.

BACKGROUND: There are few investigations of the changes in tricuspid valve (TV) and right ventricular (RV) morphology following bidirectional cavopulmonary anastomosis (BCPA). METHODS AND RESULTS: The 2-D echocardiograms of 35 children (male, n=23; female, n=12; median age, 6 months; range, 3-10 months) with hypoplastic left heart syndrome, 1 month before and after BCPA performed between 2005 and 2011, were retrospectively reviewed. Patients who underwent TV repair at BCPA were excluded. From the 4-chamber view, the coaptation length, vena contracta width and RV end-diastolic area before and after BCPA were measured and indexed to surface area. The severity of tricuspid regurgitation was graded qualitatively. After BCPA, RV end-diastolic area decreased from 2,951 ± 584 to 2,580 ± 591 mm(2)/m(2) (P<0.001). The coaptation length of the anterior leaflet (8.8 ± 5.8 vs. 11.0 ± 6.2 mm/m(2), P=0.0014) and of the septal leaflet (13.5 ± 5.3 vs. 15.8 ± 5.4mm/m(2), P=0.0072) increased after BCPA. The vena contracta width decreased (5.8 ± 4.9 vs. 4.3 ± 4.2 mm/m(2), P=0.035), although there was no change in tricuspid regurgitation grade after BCPC (1.4 ± 0.7 vs. 1.4 ± 0.9, P=0.234). CONCLUSIONS: In children with hypoplastic left heart syndrome after BCPA, the coaptation length of the anterior and septal leaflets of the TV improved concomitantly with vena contracta width and RV end-diastolic area despite unchanged tricuspid regurgitation grade. This suggests that favorable RV and TV remodeling accompanies the reduction in RV volume load following BCPA.

Tricuspid valve repair improves early right ventricular and tricuspid valve remodeling in patients with hypoplastic left heart syndrome.

OBJECTIVE: Tricuspid regurgitation is a significant risk factor for reoperation and mortality in patients with hypoplastic left heart syndrome. The effects of tricuspid valve repair on quantitative measures of right ventricle and tricuspid valve remodeling have not been well documented. METHODS: We reviewed retrospectively the 2-dimensional echocardiograms of 17 tricuspid valve repairs (male, n = 12; female, n = 5; median age, 30 months; age range, 1.5-53 months) performed 1 month before and after tricuspid valve repair between 2005 and 2011. From the apical 4-chamber view, we measured right ventricle end-diastolic area, right ventricle fractional area change, and tricuspid valve leaflet coaptation length. The severity of tricuspid regurgitation was graded qualitatively. A 2-sided paired t test was used to compare changes in tricuspid valve and right ventricle outcomes, and the Wilcoxon signed-rank test was used to compare changes in tricuspid regurgitation grades. RESULTS: Right ventricle end-diastolic area decreased significantly after tricuspid valve repair from 14.1 ± 5.2 to 11.8 ± 3.9 cm(2) (P = .001), whereas right ventricle fractional area change declined from 44.4% ± 6.4% to 39.7% ± 8.5% (P = .016). The coaptation length of the lateral and septal leaflet improved significantly after tricuspid valve repair (0.4 ± 2.4 mm vs 3.1 ± 2.7 mm, P = .002; 2.0 ± 2.7 vs 3.4 ± 2.0 mm, P = .036; respectively). Furthermore, the tricuspid regurgitation grade improved after tricuspid valve repair (3.1 ± 0.6 to 1.7 ± 0.9, P < .001). CONCLUSIONS: Tricuspid valve repair improved significantly the tricuspid valve coaptation length and reduced right ventricle volume in children with hypoplastic left heart syndrome. Further follow-up of decreased right ventricle function is required to determine whether this is a temporary phenomenon related to reduced right ventricle preload, permanent right ventricle dysfunction from late repair of the tricuspid valve, or unavoidable sequelae of a right ventricle exposed to systemic vascular resistance.

Extracorporeal membrane oxygenation following Norwood stage 1 procedures at a single institution.

Extracorporeal membrane oxygenation (ECMO) is an important circulatory assist for children with refractory cardiopulmonary dysfunction, but its role and indications after a stage 1 Norwood procedure are controversial. We assessed outcomes and risk factors in patients who underwent a Norwood palliation and ECMO at our institution. We retrospectively reviewed all patients who underwent a Norwood procedure and were supported with ECMO between January 1998 and January 2010. Of the 91 children who underwent a Norwood procedure during the study period, there were 15 postoperative runs of ECMO in 12 patients. The diagnoses of the patients included five with hypoplastic left heart syndrome, five with a hypoplastic left heart syndrome variant, and two with critical aortic stenosis. A total of four patients underwent bilateral pulmonary artery banding, and two patients underwent aortic valvuloplasty before the stage 1 Norwood procedure. The mean age of the patients was 28±30 days, and mean body weight was 2.6±0.5kg at the induction of ECMO. The indications for ECMO were low cardiac output in six children, circulatory collapse needing cardiopulmonary resuscitation in six children, and hypoxemia in three children. Five of the 12 patients were successfully weaned from ECMO. The significant risk factors for the inability to be weaned from ECMO were a history of circulatory collapse requiring cardiopulmonary resuscitation, and the induction of ECMO in the intensive care unit. Induction of ECMO may be considered earlier when hemodynamics are unstable in impaired patients following a stage 1 Norwood procedure to avoid circulatory collapse.

Transfusion-free neonatal cardiopulmonary bypass using a TinyPump.

BACKGROUND: We devised a miniaturized circuit incorporating a TinyPump in the venous line to amplify the venous return. We compared this system to the conventional blood-primed circuit and investigated whether this circuit could maintain hematocrit levels without blood transfusion and reduce coagulation and inflammatory cascades. METHODS: Thirteen 1-week-old piglets (3.7 ± 0.2 kg) were divided into group M (miniaturized circuits with TinyPump-assisted venous drainage without blood, n = 7) and group C (conventional circuits with blood priming, n = 6). Cardiopulmonary bypass (CPB) was performed at 150 to 180 mL·kg(-1)·min(-1) for 2 hours, including 60 minutes of cardioplegic cardiac arrest. Modified ultrafiltration (MUF) was subsequently performed. Data were acquired before CPB and after the end of MUF. RESULTS: The priming volume including the hemofilter circuit of the main circuit required 152 mL in group M and 300 mL in group C. The mean hematocrit values in group M and group C were not significantly different during CPB (21.5% ± 2.0% versus 23.2% ± 1.3%) or after MUF (30.7% ± 2.1% versus 32.9% ± 4.0%). After MUF, group M had lower thrombin-antithrombin complex levels (16.7 ± 5.0 ng/mL versus 28.4 ± 8.4 ng/mL, p < 0.01) and interleukin-8 levels (2,867 ± 758 pg/mL versus 13,730 ± 5,220 pg/mL, p < 0.01) than group C. The pulmonary vascular resistance index was lower in group M after MUF (4,105 ± 862 dynes·cm(-5)·kg(-1) versus 6,304 ± 1,477 dynes·cm(-5)·kg(-1), p < 0.01). The lung water content was also better in group M (83.7% ± 0.5% versus 84.9% ± 0.5%, p < 0.01). CONCLUSIONS: The minicircuit with TinyPump-assisted venous drainage successfully maintained acceptable hematocrit levels and the cardiopulmonary function in neonatal piglets. Employing this technique may attenuate blood requirements and inflammatory responses, thereby improving the clinical outcomes of neonatal open-heart surgery.

Combination of continuous irrigation and vacuum-assisted closure is effective for mediastinitis after cardiac surgery in small children.

There is still no consensus on the optimal management to treat pediatric mediastinitis. We assessed the efficacy of continuous irrigation and vacuum-assisted closure (VAC) for mediastinitis in children. This study retrospectively reviewed 20 patients aged <5 years with mediastinitis from December 2002 to December 2009. The median age at the onset was 12 months (0.6-60 months), and the median body weight was 6.9 kg (3.1-15.3 kg). Continuous irrigation was applied for extensive mediastinitis or unstable hemodynamic cases and VAC for localized or ineffective cases after continuous irrigation. A 2-4-week course of intravenous antibiotics was administered after sternal closure. Continuous irrigation was initially applied in 19 patients and VAC in one patient. VAC was employed in six patients because of recurrent or prolonged mediastinitis after continuous irrigation. All patients underwent direct sternal closure without any flap. The median duration of the hospital stay was 49.5 days (15-158 days). Although two patients died of low cardiac output, 18 children survived and had no recurrence after the discharge during a median follow-up of 14 months (1-81 months). The combination of continuous irrigation and VAC is, therefore, considered to be a safe and effective option to minimize the morbidity and mortality in pediatric mediastinitis.

Anatomical repair of a persistent left superior vena cava into the left atrium.

The anatomy of a persistent left superior vena cava (SVC) to the left atrium (LA) without the innominate vein can make it challenging to complete intracardiac repair. We reviewed our five cases of the direct end-to-side anastomosis of SVCs to facilitate anatomical repair of SVC-right atrial connection for biventricular repair. Diagnoses were two partial atrioventricular septal defect with left isomerism, one complete atrioventricular septal defect (CAVSD) with left isomerism, one CAVSD without isomerism and one atrioventricular discordance and double outlet right ventricle with right isomerism. Mean age at the operation was 20+/-23 months (4-58 months) and body weight was 7.8+/-3.4 kg (4.8-12.7 kg). After completion of intracardiac repair, the SVC to LA was divided and end-to-side anastomosed to the SVC to the right atrium during cardiopulmonary bypass. No early or late death occurred during follow-up of 14.4+/-6.9 months (7-23 months). None of the patients developed an obstruction at the anastomosis site of the SVCs. The direct end-to-side anastomosis of SVCs achieved an excellent anatomical SVC-right atrium connection in complex congenital heart diseases.

Effect of a miniaturized cardiopulmonary bypass system on the inflammatory response and cardiac function in neonatal piglets.

The cognitive impairment and hemodynamic instability after neonatal cardiac surgery with cardiopulmonary bypass (CPB) might be exacerbated by hemodilution. Therefore, this study investigated the impact of different bloodless prime volumes on the hemodynamics and the inflammatory response by a miniaturized CPB system in neonatal piglets. The bypass circuit consisted of a Capiox RX05 (Capiox Baby RX, Terumo Corp., Tokyo, Japan) oxygenator and 3/16 internal diameter arterial and venous polyvinyl chloride tubing lines, with a minimum 75 mL prime volume. Twelve 1-week-old piglets were placed on a mild hypothermic CPB (32 degrees C) at 120 mL/kg/min for 2 h. The animals were divided into two groups, based on the volume of the prime solution. The priming volume was 75 mL in Group I and 175 mL in Group II. No blood transfusions were performed, and no inotropic or vasoactive drugs were used. The interleukin-6 (IL-6) and thrombin-antithrombin (TAT) complex levels, as well as right ventricular and pulmonary functions, were measured before and after CPB. Group I had low levels of IL-6 and TAT immediately after CPB (4370 +/- 2346 vs. 9058 +/- 2307 pg/mL, P < 0.01 and 9.9 +/- 7.7 vs. 25.1 +/- 8.8 ng/mL, P < 0.01, respectively). Group I had significantly improved cardiopulmonary function, cardiac index (0.22 +/- 0.03 vs. 0.11 +/- 0.05 L/kg/min, P < 0.001), and pulmonary vascular resistance index (7366 +/- 2860 vs. 28 620 +/- 15 552 dynes/cm(5)/kg, P < 0.01) compared with Group II. The miniaturized bloodless prime circuit for neonatal CPB demonstrated that the influence of hemodilution can reduce the subsequent inflammatory response. In addition, a low prime volume could therefore be particularly effective for attenuating pulmonary vascular resistance and right ventricular dysfunction in neonates.

The benefits of high-flow management in children with pulmonary atresia.

The high-flow management of cardiopulmonary bypass (CPB; >or=2.4 L/min/m(2)) is a standard strategy used at this institute for children with pulmonary atresia (PA) due to a fear that the blood flow may be diverted by the major/minor aortopulmonary-collateral-arteries and hypervascularization due to long-term hypoxia. The purpose of this study was to describe the validity of high-flow management in children with PA. The CPB records of 23 children with PA who underwent a definitive biventricular repair between Feb 2006 and Nov 2008 were retrospectively reviewed. The mean age at the operation was 33 +/- 22 months. The blood-pressure during bypass was controlled with the same protocol. The mean cooling-temperature was 28.4 +/- 3.7 degrees C. The mean minimum hematocrit was 25.0 +/- 3.4%. The mean maximum bypass flow index at the initiation, the mean maximum flow index during aortic cross-clamping, the mean minimum flow index during aortic cross-clamping, and the mean maximum flow index after rewarming were 3.1 +/- 0.5, 3.1 +/- 0.5, 2.6 +/- 0.4, and 3.2 +/- 0.4 L/min/m(2), respectively. The higher bypass flow indexes significantly correlated with the lower serum lactate levels. The lowest oxygen delivery during CPB had significant influences on the urine output during bypass (R = 0.547, P = 0.007), the serum lactate levels at the end of CPB (R = -0.442, P = 0.035), and the postoperative thoracic effusion (R = -0.459, P = 0.028). A bypass flow index of 2.4 L/min/m(2) may not be sufficient and the maximum requirement of bypass flow index may be 3.2 L/min/m(2) or more in this patient population.

Ultrafiltration of priming blood before cardiopulmonary bypass attenuates inflammatory response and maintains cardiopulmonary function in neonatal piglets.

Blood priming is necessary for cardiopulmonary bypass (CPB) in neonates to avoid excessive hemodilution; however, transfusion-related inflammation affects postCPB outcomes in neonatal open-heart surgery. We hypothesized that ultrafiltration of priming blood before CPB may reduce inflammatory mediators in priming blood and postCPB inflammatory responses, thereby improving cardiopulmonary function. Twelve 1-week-old piglets (3.5 +/- 0.2 kg) were divided into two groups. Group U (n = 6) employed the priming blood ultrafiltrated before CPB, but group N (n = 6) used the nonultrafiltrated blood. Cardiopulmonary bypass was performed for 2 hours and then modified ultrafiltration (MUF) was conducted. Data were acquired before CPB and after MUF. The values of K+, serotonin, and IL-8 in priming blood was significantly decreased after ultrafiltration (8.2 +/- 2.6 vs. 4.2 +/- 0.8 mEq/L, p < 0.01, 234 +/- 96 vs. 74 +/- 42 ng/ml, p < 0.01, 78.4 +/- 5.1 vs. 64.5 +/- 59.1 pg/ml, p < 0.05). Group U after MUF had lower thrombin-antithrombin complex levels (23.9 +/- 5.1 vs. 33.7 +/- 4.6 ng/ml, p < 0.01) and lower IL-8 levels in airway fluid (925 +/- 710 vs. 2495 +/- 1207 pg/ml, p < 0.05) than group N. Cardiac output and arterial PO2 after MUF in group U were also higher (1.13 +/- 0.21 vs. 0.69 +/- 0.22, p < 0.01, 340 +/- 190 vs. 149 +/- 84 mm Hg, p < 0.05). The ultrafiltration of blood priming before CPB attenuated activation of the coagulation pathway and inflammatory responses and preserved cardiopulmonary function in neonatal piglets.

Single center experience with a low volume priming cardiopulmonary bypass circuit for preventing blood transfusion in infants and small children.

This retrospective study analyzed the current practice of blood transfusion-free open-heart surgery in 536 children weighing 5-20 kg undergoing surgery between 2004 and 2007. A miniaturized cardiopulmonary bypass (CPB) circuit was used (priming volume; 300 ml for the flow rate <1,500 ml/min; 550 ml for the flow rate of 1500-2300 ml/min). Modified ultrafiltration was routinely performed. Criteria for blood transfusion during CPB included a hematocrit of <20% and/or mixed venous oxygen saturation of <65%. Transfusion during CPB was avoided in 264 (49.3%) of the 536 patients (5-10 kg group, 29.0%; 11-15 kg group, 67.4%; 16-20 kg group, 80.8%). There was no neurological complication related to hemodilution. Multiple logistic regression analysis revealed that body weight, preoperative hematocrit, priming volume of CPB circuit, CPB time, and lowest hematocrit during CPB predict requirement of blood transfusion (p < 0.01). Transfusion rate was lowest in the atrial septal defect group (5.6%) and highest in tetralogy of Fallot group (78.7%), being associated with complexity of diagnosis and procedure required. Blood transfusion-free open-heart surgery may be achieved in the half of the patients weighing 5-20 kg, and further miniaturization of CPB circuit and refinement of perfusion strategy might reduce transfusion rate in patients <10 kg and/or with complex congenital heart disease.

Effect of modified ultrafiltration on postoperative course in neonates with complete transposition of the great arteries undergoing arterial switch operation.

BACKGROUND: The purpose of the present study was to evaluate the effect of modified ultrafiltration (MUF) on neonates with transposition of the great arteries (TGA) undergoing arterial switch operation. METHODS AND RESULTS: The current study included 36 neonates who underwent an arterial switch operation between 1998 and 2006. Arterio-venous MUF was done in 15 patients (MUF-treated group) and the other 21 patients were controls. Parameters included hematocrit, hemodynamics, pulmonary function, drain loss, leak of peritoneal fluid, length of intubation, and intensive care unit (ICU) stay. The hematocrit increased from 34+/-2% to 47+/-4% in the MUF-treated group. Blood pressure in the MUF-treated group was significantly increased without any change of central venous or left atrial pressure. Post-operative oxygenation in the MUF-treated group was greater than that of the control group (P/F ratio: 258+/-92 vs 170+/-100 mmHg, p<0.05), which did not contribute to decrease in intubation time (54+/-33 vs 52+/-29 h, p=NS). Post-operative chest drain loss and peritoneal fluid leak were comparable. The ICU stay in the MUF-treated group was significantly shorter than that in the controls (101+/-34 vs 139+/-42 h, p<0.05). CONCLUSIONS: MUF brought improvement in blood pressure and gas exchange capacity and subsequent shorter ICU stay. MUF did not have significant impact on intubation time and capillary leak.

Impact of miniaturization of cardiopulmonary bypass circuit on blood transfusion requirement in neonatal open-heart surgery.

This study was undertaken to determine the impact of miniaturization of a cardiopulmonary bypass (CPB) circuit on blood transfusion and hemodynamics in neonatal open-heart surgery. Neonates (n = 102) undergoing open-heart surgery between 2002 and 2006 were included and divided into three groups: group 1 (n = 28), Dideco 902 oxygenator + 5/16" line; group 2 (n = 29), Dideco 901 oxygenator + 1/4" line; group3 (n = 45), Dideco 901 oxygenator + 3/16" arterial + 1/4" venous line. Amount of priming volume, blood and bicarbonate sodium use during CPB, and hemodynamics were compared. Priming volume in the groups 2 and 3 was significantly less compared with the group 1 (group 1, 575 +/- 37 ml; group 2, 328 +/- 12 ml, group 3, 326 +/- 5 ml, p < 0.05). Blood transfusion and bicarbonate sodium use during CPB in groups 2 and 3 were significantly less compared with group 1. Hemodynamics during CPB was comparable. There were no differences between groups 2 and 3 in any parameter. Miniaturization of the CPB circuit resulted in decrease in priming volume and subsequent reduction in blood and bicarbonate sodium use. Downsizing the lines had minimal impact on any of the parameters studied, and further efforts should be made to achieve neonatal open-heart surgery without blood transfusion.

Efficacy of a miniature centrifugal rotary pump (TinyPump) for transfusion-free cardiopulmonary bypass in neonatal piglets.

We have developed a miniaturized semiclosed cardiopulmonary bypass (CPB) circuit incorporating a centrifugal blood pump (TinyPump) with a volume of 5 ml. The current study was undertaken to evaluate the hemolytic performance of the TinyPump in comparison with the BioPump and to investigate the impact of different CPB circuit volumes on hemodilution, coagulation, and the inflammatory response. Twelve 1-week-old piglets (3.4 +/- 0.2 kg) were used. The circuit comprised a centrifugal pump, a membrane oxygenator, and a cardiotomy reservoir. Cardiopulmonary bypass was conducted with mild hypothermia at 150 ml/kg/min for 3 hours. Transfusion was not performed. Priming volume was 68 ml for the circuit with the TinyPump and 111 ml for the circuit with the BioPump. Although the TinyPump required higher speed, plasma free hemoglobin levels after CPB were not different between the groups. After CPB, the TinyPump group had a significantly higher hematocrit (27% +/- 3% vs. 23% +/- 3%) and lower platelet reduction rate, lower thrombin-antithrombin complex levels, and lower interleukin-6 levels. Better lung compliance with less water content was observed in the TinyPump group. The TinyPump maintained CPB with acceptable hemolysis and lower inflammatory responses. This miniaturized CPB circuit may make transfusion-free open heart surgery feasible in neonates and would help to prevent postoperative organ dysfunction.