THERAPEUTIC STRATEGIES IN REFRACTORY LOW- CARDIAC-OUTPUT SYNDROME IN NEWBORNS AND CHILDREN

A refractory low-cardiac-output syndrome is, in pediatric patients, mo st often due to impaired myocardial function after corrective surgery in congenital heart disease. Therapy has to focus on postoperative ada ptation, which usually takes place within a few days. We report on thr ee therapeutic strategies to ''bridge'' this phase of postoperative ad aptation. Improving the contractile state of the myocardium using enox imone was attempted in 16 neonates with low-cardiac-output syndrome re fractory to catecholamines (Dosage: loading-dose 1 mg/kg in 10 min int ravenously, followed by an infusion of 10 mcg/kg/min). In 12/16 neonat es cardiac index increased by more than 20 % (''responder''), while in 4/16 neonates cardiac index remained unchanged (''non-responder''). A ll non-responders succumbed due to refractory low-cardiac-output syndr ome, while only one responder died in low-cardiac-output syndrome. Hem odynamically, enoximone resulted in an increase of cardiac index and s troke volume (p < 0.003), a reduced systemic vascular resistance (p < 0.0022), and reduced right and left atrial pressures (p < 0.003). Hear t rate and mean arterial pressure remained unchanged. No rhythm distur bances were observed. Another therapeutic approach to postoperative lo w-cardiac-output syndrome is atrial decompression by creating an atria l septal defect. Due to the possibility of later transcatheter closure of these defects, the acceptance for the intraoperative creation of a n atrial communication to decompress the right or left atrium is incre ased. The defect size is critical and should be below 9 mm, so that th e Rashkind-PDA-Occluder can be used for later transcatheter closure. W e performed such a ''surgical-interventional'' decompression in 18 pat ients (age : 2 weeks to 7 years). In six patients the atrial defect wa s created because of an underdeveloped left ventricle (body weight 2,9 -9,2 kg), in 12 patients for right atrial decompression during a total cavopulmonary shunt (body weight 15.2-54.2 kg). A spontaneous closure of the defect did not occurred in any of the patients, thus, transven ous closure of the defect was performed 2 to 10 weeks postoperatively. In the follow-up period of 4 to 22 months no complications such as th rombus formation, thromboembolic events or infections occurred. In low -cardiac-output syndrome refractory to all therapeutic measures mechan ical circulatory support is the final method to keep the patient alive . In 11 children with refractory low-cardiac-output syndrome mechanica l circulatory support was performed. In three of these, extracorporal membrane oxygenation (ECMO) was used, in eight children a ventricular assist device (Berlin Heart) was used. The age ranged from 2 weeks to 16 years (mean 8.5 years). In none of the patients did ventricular fun ction normalize during the assisted circulation. Thus, circulatory sup port was performed as a bridge to transplant for a duration of 2 to 71 days (mean 16.3 days). Cardiac transplantation was performed in eight patients; five of these survived, while two who were transplanted die d of early transplant failure. Persisting multiorgan failure despite a dequate circulatory support was observed in three patients; it can be speculated that circulatory support was started too late in these pati ents.