Acquired von Willebrand syndrome in congenital heart disease surgery: results from an observational case-series.

Essentials Bleeding complications during congenital heart disease surgery in neonatal age are very common. We report the perioperative incidence of acquired von Willebrand syndrome (aVWS) in 12 infants. aVWS was detected in 8 out of 12 neonates and infants intraoperatively after cardiopulmonary bypass. Ten patients received von Willebrand factor concentrate intraoperatively and tolerated it well. SUMMARY: Background Cardiac surgery of the newborn and infant with complex congenital heart disease (CHD) is associated with a high rate of intraoperative bleeding complications. CHD-related anatomic features such as valve stenoses or patent arterial ducts can lead to enhanced shear stress in the blood stream and thus cause acquired von Willebrand syndrome (aVWS). Objective To evaluate the intraoperative incidence and impact of aVWS after cardiopulmonary bypass (CPB) in neonates and infants with complex CHD. Patients/Methods We conducted a survey of patients aged < 12 months undergoing complex cardiac surgery in our tertiary referral center. Twelve patients, whose blood samples were analyzed for aVWS before CPB and immediately after discontinuation of CPB on a routine basis, were eligible for the analysis. von Willebrand factor antigen (VWF:Ag), ristocetin cofactor activity (VWF:RCo), collagen binding activity (VWF:CB), VWF:multimers and factor VIII activity (FVIII:C) were determined. Results aVWS was diagnosed by VWF multimer analysis in 10 out of 12 patients (83%) prior to surgery and intraoperatively at the end of CPB in 8 out of 12 patients (66%). Ten patients received VWF/FVIII concentrate intraoperatively as individual treatment attempts during uncontrolled bleeding. They tolerated it well without intraoperative thrombotic events. One patient suffered a transient postoperative cerebral sinuous vein thrombosis. Conclusions aVWS is of underestimated incidence in complex CHD surgery. These data may offer a new approach to reduce the risk of severe bleedings and to achieve hemostasis during high-risk pediatric cardiac surgery by tailoring the substitution with von Willebrand factor concentrate.

Non-invasive measurement of renal perfusion and oxygen metabolism to predict postoperative acute kidney injury in neonates and infants after cardiopulmonary bypass surgery.

BACKGROUND: The pathophysiology of acute kidney injury (AKI) after cardiopulmonary bypass surgery for congenital heart disease is not completely understood. The aim of this study was to carry out a prospective analysis of the diagnostic value of non-invasive monitoring of renal oxygenation and microcirculation by combining laser Doppler flowmetry and tissue spectrometry. METHODS: In 50 neonates and infants who underwent repair (n = 31) or neonatal palliation (n = 19) of congenital heart disease with cardiopulmonary bypass, renal oxygenation, and microcirculatory flow, the approximate renal metabolic rate of oxygen and Doppler-based renal resistive index were determined after surgery. Correlations between these parameters and the occurrence of AKI according to the Pediatric Risk, Injury, Failure, Loss, End Stage Renal Disease criteria were investigated. RESULTS: Acute kidney injury occurred in 45% of patients after repair and in 32% after palliation. Renal oxygenation was significantly lower and the approximate renal metabolic rate of oxygen significantly higher in patients with AKI (P < 0.05). The microcirculatory flow was significantly higher in patients with AKI after neonatal palliation (P < 0.05), whereas renal resistive index was significantly higher in patients with AKI after repair (P < 0.05). The sensitivity of renal oxygenation, metabolic rate of oxygen, microcirculation, and resistive index in predicting AKI was 78-80, 73-78, 64-83, and 71-74%, respectively, with a specificity of 63-65, 54-75, 64-78, and 46-74% (area under the curve: 0.73-0.75, 0.68-0.83, 0.52-0.68, and 0.60-0.75), respectively. CONCLUSIONS: Monitoring of renal oxygen metabolism allows early prediction of AKI in infants after cardiac surgery. In contrast, renal resistive index does not allow prediction of AKI after neonatal palliation with aortopulmonary shunt establishment.

Safety, efficacy and response to a hydrocortisone rescue therapy protocol in children with refractory hypotension after cardiopulmonal bypass.

Little is known about which paediatric patients respond to hydrocortisone rescue therapy (HRT) with improvement of haemodynamic stability in refractory hypotension after cardiopulmonal bypass. Data were gathered retrospectively from children who received HRT in refractory hypotension after cardiopulmonary bypass in the period from 2000 to 2010. One hundred and sixty-six out of 1,273 children, 150 <1 year and 16 >1 year were enrolled. HRT improved haemodynamics significantly, increased blood pressure, decreased the vasoactive-inotropic score and plasma lactate concentrations in all children >1 year and in 82 % (123 out of 150) of the infants <1 year. Non-responders <1 year were significantly younger, lighter, mostly male infants and had longer cardiopulmonary bypass support time. Serum lactate and paediatric risk of mortality score were significantly higher in non-responders at time of initiation of HRT. Mortality was significantly higher in non-responders versus responders (2.44 vs. 13.5 %; p = 0.0008). HRT caused no adverse effects like electrolyte disturbances or hyperglycaemia. HRT in refractory hypotension after paediatric cardiac surgery is safe but not all infants <1 year show haemodynamic response to HRT. Non-response to HRT is associated with significantly higher mortality.

Cryorecanalization of an obstructed bronchial stent in a 12-year-old boy.

We report a 12-year-old boy who underwent stent implantation into the left main bronchus at the age of 9.5 years for palliation of severe bronchial stenosis. He had developed complete obstruction of the stent by granulation tissue resulting in respiratory deterioration and the requirement of mechanical ventilation. The stent obstruction was treated at the age of 11.5 years by cryorecanalization. In this technique, cooling of the tip of the cryoprobe is used to induce adherence of the obstructing tissue allowing the subsequent removal of tissue particles by retraction of the probe. Under general anesthesia, a miniaturized cryoprobe was advanced via the working channel of a flexible bronchoscope. Repeat maneuvers of freezing and retraction resulted in complete recanalization of the stent. Repeat bronchoscopies 4 and 12 weeks later revealed recurrent formation of some granulation tissue which was removed by repeat cryorecanalization. Seven months after the initial procedure there was a complete patency of the stent. According to our experience, cryorecanalization is a safe and effective alternative for the treatment of stent obstruction by granulation tissue. Due to the introduction of a miniaturized probe, this method is well applicable in children since it can be performed via the working channel of a flexible pediatric bronchoscope.

Comparison of imaging techniques in the diagnosis of bridging bronchus.

Bridging bronchus (BB) is a rare, congenital bronchial anomaly that is frequently associated with congenital cardiac malformations, especially left pulmonary artery sling. It represents an anomalous bronchus to the right originating from the left main bronchus. Discrimination from other bronchial anomalies is important, since BB is frequently associated with bronchial stenoses due to abnormal cartilage rings. This case study describes the findings of bronchoscopy, bronchography and multidetector computed tomography (MDCT) in three patients. Bronchoscopy was helpful in the description of the severity and length of bronchial stenoses. However, it was not possible to establish a diagnosis of BB based on this method in two patients, since it is difficult or even impossible to differentiate the bifurcation from the pseudocarina. It was not possible to establish the correct diagnosis in all patients based on bronchography or MDCT. MDCT was able to depict the relationship of bronchial and vascular structures, which is particularly important in patients with pulmonary artery sling. Multidetector computed tomography is preferable to bronchography as it is less invasive and due to its short acquisition time it can be performed in children with severe respiratory disease. In the current authors' experience, detection of cartilage rings still requires flexible bronchoscopy.