Long-Term Mechanical Circulatory Support in Pediatric Patients.

This retrospective study reviews our results regarding the long-term support in pediatric patients using two ventricular assist systems between January 2008 and April 2014. We implanted the Berlin Heart EXCOR in 29 patients (median age 3.4 years [interquartile range (IQR) 0.2-16.5], median weight 13 kg [IQR 4.2-67.2]). Twenty-two patients (75.8%) received a left ventricular assist device. Three patients (10.3%) had single-ventricle physiology. One patient (3.4%) had mechanical mitral valve prosthesis. The HeartWare System was implanted in nine patients. The median age was 15.6 years (IQR 12.2-17.9), and the median weight was 54.9 kg (IQR 27.7-66). In the Berlin Heart group, the median support time was 65 days (IQR 4-619), with 3647 days of cardiac support. Nineteen patients (65.5%) were transplanted, six patients (20.7%) recovered, one patient (3.4%) is on support, and three patients (10.3%) died on support. Survival rate was 89.7%. Fourteen blood pumps had been exchanged. Four patients (13.8%) had local signs of infection, and three patients (10.3%) had neurological complications. In the HeartWare group, the median support time was 180 days (IQR 1-1124), with 2839 days of cardiac support. Four patients (44.4%) had local signs of infection, and three (33.3%) had neurological complications. Eight patients (88.9%) have been transplanted, and one patient (11.1%) died on support. Survival rate was 88.9%. Excellent survival is possible after long-term mechanical circulatory support in patients with two- and single-ventricle physiology with a low rate of adverse events.

Reopening acutely occluded cavopulmonary connections in infants and children.

Little is known about the outcome of acute thrombotic occlusion of segments of the cavopulmonary connections (CPC) in infants and children with univentricular hearts. Early recognition and aggressive therapy may result in successful salvage of some of these patients. Five consecutive patients (age range 4-8 months) presenting with acute occlusion of a CPC segment underwent emergency cardiac catheterization. After angiographic confirmation, the occluded segment was crossed using an endhole catheter and guidewire combination. Serial balloon dilation and stent implantation (ten stents in total) were undertaken to recanalize the occlusion. The stents used were mounted on balloons ranging in diameter from 6 mm to 8 mm, depending on the size of the native vessel. The sites of occlusion were the left pulmonary artery (n=4), and the left-sided superior caval vein (n=3). All occlusions could be successfully recanalized. In three patients, early reocclusion necessitated either surgery or repeat catheterization and angioplasty. There were two early deaths, due to recurrent thrombotic obstruction confirmed either at autopsy or angiography. The remaining patients are alive and well; the majority of survivors have undergone completion of the Fontan operation. A high index of clinical suspicion combined with aggressive therapy can result in successful recanalization in some infants with acutely occluded CPC segments, with acceptable long-term outcome.

Effects of pH management during deep hypothermic bypass on cerebral microcirculation: alpha-stat versus pH-stat.

OBJECTIVE: There is controversy regarding the optimal pH strategy during deep hypothermic bypass in children. We directly visualized the effects of the pH-stat and alpha-stat strategy on cerebral microcirculation (including leukocyte/endothelial cell interactions) in a piglet model using intravital fluorescence microscopy. METHODS: Two groups of 5 piglets (mean weight 9.6+/-1.3 kg) with a cranial window over parietal cerebral cortex underwent 10-minute normothermic bypass, 40-minute cooling on cardiopulmonary bypass ([CPB] Hct 30%, 100 mL/kg/min), 60-minute circulatory arrest at 15 degrees C, and 40-minute rewarming with alpha-stat (group alpha) or pH-stat (group pH). Plasma was labeled with fluorescein-ITC-dextran for assessment of microvascular diameter. Circulating leukocytes were labeled and observed in postcapillary venules for adhesion before and up to 120 minutes after CPB. Cerebral tissue oxygenation was evaluated by quantification of NADH autofluorescence, which increases during ischemia. RESULTS: At the end of normothermic bypass diameter of cerebrocortical microvessels increased to 116+/-9% (alpha) versus 119+/-10% (pH) of pre-CPB baseline values. During cooling microvascular diameter decreased in group alpha and significantly increased in group pH (89+/-11% (alpha) versus 132+/-13% (pH) at the end of cooling; P<0.001). During the first 10 minutes of rewarming, the cerebral microvascular diameter was significantly larger when the pH stat strategy was used. Tissue oxygenation at the end of cooling was significantly greater in the pH-stat group (P=0.008). On reperfusion, the pH-stat strategy resulted in significantly more rapid return of tissue oxygenation toward baseline although at the end of rewarming the metabolic recovery was complete in both groups. The whole body lactate during early rewarming was significantly less with the pH stat strategy. There was no significant difference between the groups regarding the number of adherent leukocytes throughout the time course of the experiment. CONCLUSIONS: pH-stat management increases tissue oxygenation during deep hypothermic bypass and after circulatory arrest. Leukocyte/endothelial cell interactions during hypothermic bypass are mild with both alpha-stat and pH-stat.