Impact of Bicuspid Aortic Valve Morphology on Aortic Valve Disease and Aortic Dilation in Pediatric Patients.

Bicuspid aortic valve (BAV) is the most common congenital heart defect. BAV is associated with aortic stenosis and insufficiency, and aortic dilation in adult groups, but data in pediatric groups are limited. We sought to assess the impact of BAV morphology on aortic valve disease and aortic dilation in pediatric patients. We performed a retrospective review of all echocardiograms in patients with isolated BAV who were followed at our institution from July 2002 to July 2012. BAV morphology, aortic valve stenosis and/or insufficiency, and aortic dimensions were measured manually. Comparisons were made between right-left cusp fusion (RL) and right-noncoronary cusp fusion (RN) BAV morphologies. Generalized least square models were fit to analyze the impact of specific variables on aortic dilation. There were 1075 echocardiograms in 366 patients (72% male) with isolated BAV. Aortic valve insufficiency and stenosis were more common in RN (p < 0.001 for both). The median aortic sinus Z score was higher in the RL (0.47; IQR - 0.31 to 1.44) than in the RN group (0.02; - 0.83 to 0.82) (p < 0.001). There was no difference in median ascending aorta Z score between groups. Patients with the highest weights had larger aortas (p < 0.001), but the absolute difference between the highest and lowest weight groups was small (1.5 mm). The impact of BAV morphology on aortic valve disease and aortic dilation in pediatric patients presages that seen in adults. Patient body weight does not make significant clinical impacts on aortic diameters, suggesting that Z scores for aortic diameters should be based on ideal body weights.

RBC transfusion in pediatric patients supported with extracorporeal membrane oxygenation: is there an impact on tissue oxygenation?

OBJECTIVE: To examine first the RBC transfusion practice in pediatric patients supported with extracorporeal membrane oxygenation and second the relationship between transfusion of RBCs and changes in mixed venous saturation (SvO2) and cerebral regional tissue oxygenation, as measured by near-infrared spectroscopy in patients supported with extracorporeal membrane oxygenation. DESIGN: Retrospective observational study. SETTING: Pediatric, cardiovascular, and neonatal ICUs of a tertiary care children's hospital. PATIENTS: All pediatric patients supported with extracorporeal membrane oxygenation between January 1, 2010, and December 31, 2010. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: There were 45 patients supported with extracorporeal membrane oxygenation. The median (interquartile range) phlebotomy during extracorporeal membrane oxygenation was 75 mL/kg (33, 149 mL/kg). A total of 617 transfusions were administered (median, 9 per patient; range = 1-57). RBC volumes transfused during extracorporeal membrane oxygenation support were 254 mL/kg (136, 557) and 267 mL/kg (187, 393; p = 0.82) for cardiac and noncardiac patients, respectively. Subtracting the volume of RBCs used for extracorporeal membrane oxygenation circuit priming, median RBC transfusion volumes were 131 and 80 mL/kg for cardiac and noncardiac patients, respectively (p = 0.26). The cardiac surgical patients received the most RBCs (529 vs 74 mL/kg for nonsurgical cardiac patients). The median hematocrit maintained during extracorporeal membrane oxygenation support was 37%, with no difference between cardiac and noncardiac patients. Patients supported with extracorporeal membrane oxygenation were exposed to a median of 10.9 (range, 3-43) individual donor RBC units. Most transfusions resulted in no significant change in either SvO2 or cerebral near-infrared spectroscopy. Only 5% of transfusions administered (31/617) resulted in an increase in SvO2 of more than 5%, whereas an increase in cerebral near-infrared spectroscopy of more than 5 was only observed in 9% of transfusions (53/617). Most transfusions (73%) were administered at a time when the pretransfusion SvO2 was more than 70%. CONCLUSIONS: Patients supported with extracorporeal membrane oxygenation were exposed to large RBC transfusion volumes for treatment of mild anemia resulting from blood loss, particularly phlebotomy. In the majority of events, RBC transfusion did not significantly alter global tissue oxygenation, as assessed by changes in SvO2 and cerebral near-infrared spectroscopy. Most transfusions were administered at a time at which the patient did not appear to be oxygen delivery dependent according to global measures of tissue oxygenation.