Elevated free hemoglobin and decreased haptoglobin levels are associated with adverse clinical outcomes, unfavorable physiologic measures, and altered inflammatory markers in pediatric cardiac surgery patients.

BACKGROUND: There are data suggesting that free hemoglobin (Hb), heme, and iron contribute to infection, thrombosis, multiorgan failure, and death in critically ill patients. These outcomes may be mitigated by haptoglobin. STUDY DESIGN AND METHODS: 164 consecutively treated children undergoing surgery for congenital heart disease were evaluated for associations between free Hb and haptoglobin and clinical outcomes, physiologic metrics, and biomarkers of inflammation RESULTS: Higher perioperative free Hb levels (and lower haptoglobin levels) were associated with mortality, nosocomial infection, thrombosis, hours of intubation and inotropes, increased interleukin-6, peak serum lactate levels, and lower nadir mean arterial pressures. The median free Hb in patients without infection (30 mg/dL; 29 interquartile range [IQR], 24-52 mg/dL) was lower than in those who became infected (39 mg/dL; IQR, 33-88 mg/ 31 dL; p = 0.0046). The median mechanical ventilation requirements were 19 (IQR, 7-72) hours in patients with higher levels of haptoglobin versus 48 (IQR, 18-144) hours in patients with lower levels (p = 0.0047). Transfusion dose, bypass duration, and complexity of surgery were all significantly correlated with Hb levels and haptoglobin levels. Multivariate analyses demonstrated that these variables were independently and significantly associated with outcomes. CONCLUSIONS: Elevated pre- and postoperative levels of free Hb and decreased levels of haptoglobin were associated with adverse clinical outcomes, inflammation, and unfavorable physiologic metrics. Transfusion, RACHS score, and duration of bypass were associated with increased free Hb and decreased haptoglobin. Further investigation of the role of hemolysis and haptoglobin as potential mediators or markers of outcomes is warranted.

Modified Repair of Type I and II Truncus Arteriosus Limits Early Right Ventricular Outflow Tract Reoperation.

Repair of truncus arteriosus often requires early right ventricular outflow tract (RVOT) reoperation. Using a modified repair, the branch pulmonary arteries are left in situ, which may avoid earlier RVOT reoperation. We hypothesized that our modified repair for type I and II truncus arteriosus would extend the time to RVOT reoperation. Infants with truncus arteriosus were divided into 2 groups: (1) traditional technique where the branch pulmonary arteries are excised from the truncal root, or (2) modified repair where the branch pulmonary arteries are left in situ and septated from the truncal root. Regardless of the approach, a bioprosthetic conduit or homograft was used to establish right ventricular to pulmonary artery continuity. Follow-up pulmonary artery angiograms were used to assess for branch pulmonary artery stenosis. From 54 infants (modified repair: 33, traditional technique: 21), there were no significant differences in age at repair, gender, or type of truncus arteriosus. With 100% follow-up, use of the modified repair resulted in a lower rate of branch pulmonary artery stenosis, and greater freedom from surgical branch pulmonary arterioplasty. Five- and 10-year freedom from RVOT reoperation (5 years: modified-81.5% vs traditional-30.5%, P = 0.004; 10 years: modified-53.3% vs traditional-30.5%, P = 0.01) favored the modified repair. Cox regression analysis demonstrated that the modified repair was associated with an independently lower risk for RVOT reoperation (hazard ratio: 0.08, confidence interval: 0.01, 0.75, P = 0.02). Thus, maintaining the branch pulmonary artery architecture resulted in greater freedom from RVOT reoperation.

A modified LVAD technique to augment caval and pulmonary arterial blood flow in the "failing Fontan" circulation.

BACKGROUND: There are minimal circulatory support options for patients with a failing Fontan. The Heartmate II (HMII) left ventricular assist device (Thoratec, Bedford, MA) in its packaged state cannot augment caval/pulmonary arterial blood flow. AIM: We hypothesized that a modified HMII pump could augment caval and pulmonary arterial blood flow. METHODS: A bifurcated ringed Gore-Tex graft (W. L. Gore & Associates, Flagstaff, AZ) was sewn to the HMII inflow, and the outflow graft transected and tapered from 16 mm to 8 mm in diameter. In three sheep, the inflow and outflow grafts were anastomosed end-to-side to both cava and the pulmonary artery. RESULTS: Following baseline measurements, the pump speed was increased to 8000 revolutions per minute (RPMs). Compared to baseline, at 8000 RPMs, there were no significant differences in mean arterial, central venous, or pulmonary arterial pressure. However, there was a significant decrease in right ventricular diastolic diameter (3.1 ± 0.1 vs. 1.8 ± 0.2 cm, R = 0.6, p = 0.02) and similarly a decrease in pulmonary arterial pulse pressure (8.5 ± 2.1 vs. 2.1 ± 2.9 mmHg, p = 0.01). As pump speed increased, there was a corresponding increase in pump flow and power, with a decrease in pulsatility index. CONCLUSIONS: These findings suggest that the HMII may be modified to provide caval/pulmonary circulatory support for the failing Fontan circulation.

Use of a Dacron Annular Sparing Versus Limited Transannular Patch With Nominal Pulmonary Annular Expansion in Infants With Tetralogy of Fallot.

BACKGROUND: Repair of tetralogy of Fallot (ToF) using a transannular patch can result in severe pulmonary insufficiency (PI) and subsequent right ventricular (RV) dilation. Use of a Dacron (Maquet Cardiovascular LLC, Wayne, NJ) limited transannular patch with nominal pulmonary annular expansion (LTAP) attempts to limit PI. We sought to evaluate the degree of PI and RV dilation resulting from a LTAP or annular sparing (AS) approach. METHODS: Infants less than 1 year of age undergoing ToF repair between 2000 and 2010 were divided into 2 groups: LTAP and AS RV outflow tract patch. Echocardiograms were used to determine RV dimensions and corresponding Z-values. RESULTS: From 94 infants, 48 required a LTAP and 46 required an AS patch. The preoperative pulmonary valve annulus Z-value was significantly smaller in the LTAP versus AS group (-2.7 ± 1.4 versus -0.9 ± 1.5; p < 0.001). Mean follow-up was obtained at 7.9 ± 3.4 years. Ten-year freedom from severe pulmonary insufficiency was 78.5% versus 93.2% (p = 0.3) in the LTAP and AS groups, respectively. There was no significant difference in the diameter of the RV base Z-value between groups (LTAP: 0.9 ± 0.8 versus AS: 0.0 ± 2.3; p = 0.1). Further, the freedom from reoperation at 10 years was also not significantly different between the LTAP and AS groups (95.6% versus 91.8%; p = 0.5). CONCLUSIONS: When required, a LTAP results in a similar change in RV chamber size and rate of reoperation at an intermediate-term follow-up.

Outcomes Using a Conservative Versus Liberal Red Blood Cell Transfusion Strategy in Infants Requiring Cardiac Operation.

BACKGROUND: The optimal hemoglobin for infants after cardiac operation is unknown. Red blood cells (RBCs) are commonly transfused to maintain high hemoglobin concentrations in the absence of a clinical indication. We hypothesized that infants can be managed with a postoperative conservative RBC transfusion strategy, resulting in lower daily hemoglobin concentrations, without evidence of impaired oxygen delivery (ie, lactate, arteriovenous oxygen difference [avO2diff]), or adverse clinical outcomes. METHODS: Infants weighing 10 kg or less undergoing biventricular repair or palliative (nonseptated) operation were randomly assigned to either a postoperative conservative or liberal transfusion strategy. Conservative group strategy was RBC transfusion for a hemoglobin less than 7.0 g/dL for biventricular repairs or less than 9.0 g/dL for palliative procedures plus a clinical indication. Liberal group strategy was RBC transfusion for hemoglobin less than 9.5 g/dL for biventricular repairs or less than 12 g/dL for palliative procedures regardless of clinical indication. RESULTS: After the operation of 162 infants (82 conservative [53 biventricular, 29 palliative], 80 liberal [52 biventricular, 28 palliative]), including 12 Norwood procedures (6 conservative, 6 liberal), daily hemoglobin concentrations were significantly lower within the conservative group than the liberal group by postoperative day 1 and remained lower for more than 10 days. The percentage of patients requiring a RBC transfusion, number of transfusions, and volume of transfusions were all significantly lower within the conservative group. Despite lower hemoglobin concentrations within the conservative group, lactate, avO2diff, and clinical outcomes were similar. CONCLUSIONS: Infants undergoing cardiac operation can be managed with a conservative RBC transfusion strategy. Clinical indications should help guide the decision for RBC transfusion even in this uniquely vulnerable population. Larger multicenter trials are needed to confirm these results, and focus on the highest risk patients would be of great interest.

Continuous Cardiopulmonary Bypass During the Repair of Total Anomalous Pulmonary Venous Return.

Circulatory arrest (CA) is traditionally utilized during the repair of total anomalous pulmonary venous return (TAPVR). Since 2005, we have exclusively repaired all types of TAPVR using continuous cardiopulmonary bypass. We present our technique using continuous cardiopulmonary bypass throughout the duration of the repair, by temporarily occluding the vertical vein and placing a pump sucker within the pulmonary venous confluence. This technique has been used on 29 consecutive patients and resulted in limited morbidity and absence of pulmonary vein stenosis from most recent follow-up.

Distal Transverse Arch to Left Carotid Artery Ratio Helps to Identify Infants With Aortic Arch Hypoplasia.

BACKGROUND: Aortic coarctation (CoA) with concomitant aortic arch hypoplasia (AAH) is associated with an increased risk of hypertension after surgical repair. The differentiation of CoA with or without AAH may be critical to delineate the ideal surgical approach that best ameliorates postoperative hypertension. Since 2000, we have defined CoA with AAH when the diameter of the distal transverse aortic arch is equal to or less than the diameter of the left carotid artery. We hypothesized that, based on our definition, aortic tissue from infants having CoA with AAH would demonstrate distinct genetic expression patterns as compared with infants having CoA alone. METHODS: From 6 infants (AAH, 3; CoA, 3), an Affymetrix 1.0 genome array identified genes in the coarctation/arch region that were differentially expressed between infants having CoA with AAH versus CoA alone. Reverse transcription polymerase chain reaction validated genetic differences from a cohort of 21 infants (CoA with AAH, 10; CoA, 11). To evaluate the clinical outcomes based on our definition of CoA with AAH, we reviewed infants repaired using this algorithm from 2000 to 2010. RESULTS: Microarray data demonstrated genes differentially expressed between groups. Reverse transcription polymerase chain reaction confirmed that CoA with AAH was associated with an increased expression of genes involved in cardiac and vascular development and growth, including hepsin, fibroblast growth factor-18, and T-box 2. The clinical outcomes of 79 infants (AAH, 26; CoA, 53) demonstrated that 90.1% were free of hypertension at 13 years when managed with this surgical strategy. CONCLUSIONS: These findings provide evidence that the ratio of the diameter of the distal transverse arch to the left carotid artery may be helpful to identify CoA with AAH and, when used to delineate the surgical approach, may minimize hypertension.

Longer RBC storage duration is associated with increased postoperative infections in pediatric cardiac surgery.

OBJECTIVES: Infants and children undergoing open heart surgery routinely require multiple RBC transfusions. Children receiving greater numbers of RBC transfusions have increased postoperative complications and mortality. Longer RBC storage age is also associated with increased morbidity and mortality in critically ill children. Whether the association of increased transfusions and worse outcomes can be ameliorated by use of fresh RBCs in pediatric cardiac surgery for congenital heart disease is unknown. INTERVENTIONS: One hundred and twenty-eight consecutively transfused children undergoing repair or palliation of congenital heart disease with cardiopulmonary bypass who were participating in a randomized trial of washed versus standard RBC transfusions were evaluated for an association of RBC storage age and clinical outcomes. To avoid confounding with dose of transfusions and timing of infection versus timing of transfusion, a subgroup analysis of patients only transfused 1-2 units on the day of surgery was performed. MEASUREMENTS AND MAIN RESULTS: Mortality was low (4.9%) with no association between RBC storage duration and survival. The postoperative infection rate was significantly higher in children receiving the oldest blood (25-38 d) compared with those receiving the freshest RBCs (7-15 d) (34% vs 7%; p = 0.004). Subgroup analysis of subjects receiving only 1-2 RBC transfusions on the day of surgery (n = 74) also demonstrates a greater prevalence of infections in subjects receiving the oldest RBC units (0/33 [0%] with 7- to 15-day storage; 1/21 [5%] with 16- to 24-day storage; and 4/20 [20%] with 25- to 38-day storage; p = 0.01). In multivariate analysis, RBC storage age and corticosteroid administration were the only predictors of postoperative infection. Washing the oldest RBCs (> 27 d) was associated with a higher infection rate and increased morbidity compared with unwashed RBCs. DISCUSSION: Longer RBC storage duration was associated with increased postoperative nosocomial infections. This association may be secondary in part, to the large doses of stored RBCs transfused, from single-donor units. Washing the oldest RBCs was associated with increased morbidity, possibly from increased destruction of older, more fragile erythrocytes incurred by washing procedures. Additional studies examining the effect of RBC storage age on postoperative infection rate in pediatric cardiac surgery are warranted.

Hypertensive changes within the aortic arch of infants and children with isolated coarctation.

BACKGROUND: Despite repair, a significant proportion of patients with coarctation of the aorta (CoA) present with late hypertension. Increased gene expression of aortic wall collagen and vascular smooth muscle cell markers occurs in the presence of hypertension. Before repair, a patent ductus arteriosus (PDA) limits hypertension proximal to the coarctation. We hypothesize that preoperative collagen and vascular smooth muscle expression from the aortic arch in children is variable, depending on the presence or absence of a PDA. METHODS: We analyzed the expression patterns of collagen and vascular smooth muscle cell markers in 25 children with CoA using a quantitative polymerase chain reaction. Aortic arch tissue proximal to the CoA was normalized to descending aortic tissue distal to the coarctation. Collagen-I, transforming growth factor-ß, elastin, and calponin were analyzed. RESULTS: At repair, 19 patients were aged younger than 3 months (14 with a PDA, 5 with a ligamentum arteriosum), and the remaining 6 were older than 1 year. There was no difference in age or weight between infants with or without a PDA. Infants without a PDA had the greatest difference in collagen-I expression compared with infants with a PDA (7.0 ± 1.6-fold vs 0.8 ± 1.1-fold, p = 0.01). Expression of transforming growth factor-ß (4.3 ± 1.4 vs 2.6 ± 2.3, p = 0.01) and calponin (3.7 ± 0.7 vs 0.6 ± 1.1, p = 0.05) was lower from infants with vs without a PDA. CONCLUSIONS: Our findings provide evidence of preoperative changes in the aortic arch before repair, particularly in the absence of a PDA.

The effect of repeat sternotomy during right ventricular outflow tract reconstruction.

OBJECTIVE: Right ventricular outflow tract (RVOT) reconstruction necessitates frequent reoperation. To understand the early outcomes, we analyzed our results to provide the intra- and postoperative morbidity and mortality. We hypothesized that multiple previous sternotomies do not influence the morbidity, mortality, or survival. DESIGN: We performed a retrospective review of patients who underwent reoperative RVOT reconstruction at the University of Rochester Medical Center and SUNY Upstate Medical Center from January 1, 2000 to December 31, 2009. Patients were divided into three groups based upon the number of previous sternotomies: Group 1 with one, Group 2 with two, and Group 3 with three or more previous sternotomies. RESULTS: 220 patients had reoperative RVOT reconstruction, 103 in Group 1, 71 in Group 2, and 46 in Group 3. There was no difference in the percentage of inadvertent cardiotomy between groups (Group 1: 2%, Group 2: 1%, Group 3: 2%; P =.9) The number of previous sternotomies had no effect upon infection, arrhythmia, or the percentage of patients who received a red blood cell transfusion (Group 1: 56%, Group 2: 49% Group 3: 43%; P =.3). Perioperative mortality for the entire group was 3/220 (1.4%), with no difference between groups. At a mean follow-up of 39 months, there was a survival of 98% for Groups 1 and 3 and 97% for Group 2 (P =.7). CONCLUSION: Reoperative RVOT reconstruction can safely be performed with limited morbidity and mortality. The number of previous sternotomies does not influence the rate of cardiotomy, red blood cell transfusion, or early outcome.

Decreased incidence of supravalvar pulmonary stenosis after arterial switch operation.

BACKGROUND: Supravalvar pulmonary stenosis (SVPS) is frequently observed after arterial switch. Traditionally the coronary arteries are removed from the neopulmonic root by excising the entire sinus of Valsalva. As a result, reconstruction of the neopulmonic root requires a pericardial patch encompassing two-thirds of the anastomosis between the neopulmonic root and pulmonary artery. We present a technique where the coronary arteries are removed as limited buttons of sinus tissue, leaving the transected edge of the neopulmonic root intact. We hypothesize that maintaining native arterial tissue in the anastomosis between the neopulmonic root and the pulmonary artery bifurcation reduces postoperative SVPS. METHODS AND RESULTS: We performed a retrospective review of neonates with D-transposition of the great arteries undergoing arterial switch procedure from 1996 to 2009. Charts were reviewed, and clinical outcomes recorded for each patient. Most recent echocardiograms were evaluated for right ventricular outflow tract obstruction. A total of 120 patients received arterial switch using this technique. There was 99% survival and no injuries to the coronary arteries regardless of anatomy. Total follow-up was 564 patient-years. Mean follow-up at last clinical visit was 66 ± 46 months. Evaluation of the most recent outpatient echocardiogram revealed an average peak instantaneous gradient across the neopulmonic root of 22.5 ± 5 mm Hg. Only 7 (5%) patients required reintervention (balloon dilation, n=5; surgery, n=2). CONCLUSIONS: Our technique of removing the coronary arteries as limited buttons, and anastomosis of the pulmonary artery using only native arterial tissue provides excellent midterm results with minimal SVPS.

Washing red blood cells and platelets transfused in cardiac surgery reduces postoperative inflammation and number of transfusions: results of a prospective, randomized, controlled clinical trial.

OBJECTIVES: Children undergoing cardiac surgery with cardiopulmonary bypass are susceptible to additional inflammatory and immunogenic insults from blood transfusions. We hypothesize that washing red blood cells and platelets transfused to these patients will reduce postoperative transfusion-related immune modulation and inflammation. DESIGN: Prospective, randomized, controlled clinical trial. SETTING: University hospital pediatric cardiac intensive care unit. PATIENTS: Children from birth to 17 yrs undergoing cardiac surgery with cardiopulmonary bypass. INTERVENTIONS: Children were randomized to an unwashed or washed red blood cells and platelet transfusion protocol for their surgery and postoperative care. All blood was leuko-reduced, irradiated, and ABO identical. Plasma was obtained for laboratory analysis preoperatively, immediately, and 6 and 12 hrs after cardiopulmonary bypass. Primary outcome was the 12-hr postcardiopulmonary bypass interleukin-6-to-interleukin-10 ratio. Secondary measures were interleukin levels, C-reactive protein, and clinical outcomes. MEASUREMENTS AND MAIN RESULTS: One hundred sixty-two subjects were studied, 81 per group. Thirty-four subjects (17 per group) did not receive any blood transfusions. Storage duration of blood products was similar between groups. Among transfused subjects, the 12-hr interleukin ratio was significantly lower in the washed group (3.8 vs. 4.8; p = .04) secondary to lower interleukin-6 levels (after cardiopulmonary bypass: 65 vs.100 pg/mL, p = .06; 6 hrs: 89 vs.152 pg/mL, p = .02; 12 hrs: 84 vs.122 pg/mL, p = .09). Postoperative C-reactive protein was lower in subjects receiving washed blood (38 vs. 43 mg/L; p = .03). There was a numerical, but not statistically significant, decrease in total blood product transfusions (203 vs. 260) and mortality (2 vs. 6 deaths) in the washed group compared to the unwashed group. CONCLUSIONS: Washed blood transfusions in cardiac surgery reduced inflammatory biomarkers, number of transfusions, donor exposures, and were associated with a nonsignificant trend toward reduced mortality. A larger study powered to test for clinical outcomes is needed to determine whether these laboratory findings are clinically significant.