Fate of the stented arterial duct

BACKGROUND

The technical aspects of ductal stenting have been reported, but little is known of the fate of the duct after stent implantation.

METHODS AND RESULTS

Nineteen patients underwent stent implantation to maintain ductal patency. Eight had hypoplastic left heart (HLH) syndrome, 10 had pulmonary atresia, and 1 had tricuspid atresia. Median survival with HLH was 57 (12 to 907) days. Stent implantation was successful in all cases of HLH, but there were no long-term survivors. Two well-palliated infants died at transplantation. Median survival with duct-dependent pulmonary flow was 183 (0 to 1687) days, with 3 patients well at latest follow-up (56, 55, and 9 months, respectively). There were 2 operative deaths due to ductal spasm and 4 late deaths, 1 due to duct thrombosis, 1 due to chronic lung disease, and 2 of unknown cause. Stent implantation failed in 4 of the 11 cases. Assessment of endothelialization was possible in 13 cases; the stent was partially covered in 3 and fully endothelialized in all 10 cases assessed >8 weeks after implantation. In patients stented for inadequate pulmonary flow, ductal intimal hyperplasia occurred by 9 months in all 3 survivors but responded to repeated dilation.

CONCLUSIONS

Ductal stenting cannot be recommended. In patients with HLH, it provides only short-term palliation even when combined with pulmonary artery banding. With duct-dependent pulmonary blood flow, the procedure carries high risk, and duration of palliation is poor. In patients with bilateral ducts and absent central pulmonary arteries, good palliation may be achieved, but repeated angioplasty is necessary to counteract intimal hyperplasia.

Haemolysis following implantation of duct occlusion coils

OBJECTIVES

To describe the incidence and management of haemolysis after transcatheter coil occlusion of the arterial duct.

DESIGN

Prospective clinical and echocardiographic follow up of patients who have undergone implantation of the Cook detachable duct occlusion coil.

SETTING

Tertiary paediatric cardiac centre.

PATIENTS

Five cases of haemolysis (two girls aged 6 and 11 months; three boys aged 6, 17, and 14 months) from a series of 137 duct coil implantations.

MAIN OUTCOME MEASURES

The occurrence of clinically significant haemolysis after implantation of duct occlusion coils and resolution of haematuria after completion of duct occlusion.

RESULTS

Haemolysis was detected in five of 137 procedures following implantation of Cook detachable duct coils. Four patients became symptomatic 12 hours after the procedure but in one haemolysis was detected three months later. Resolution of ongoing haemolysis was achieved within 48 hours of detection with further coil implantations, but haematuria persisted for up to 10 days. In one patient the extensive destruction of erythrocytes resulted in acute renal failure requiring peritoneal dialysis.

CONCLUSIONS

Haemolysis is an important complication after duct coil implantation. It occurred in 3.6% of 137 procedures in this series and is most likely to occur in young patients with relatively large ducts. Further coil implantation to occlude the duct completely is not only successful but technically relatively straightforward and should be undertaken early if major complications such as severe anaemia and renal failure are to be avoided.

Dystrophic calcification of the fetal myocardium

Intramural cardiac masses were detected antenatally in three fetuses by echocardiography. The masses were initially thought to be rhabdomyomas. All three pregnancies were terminated and histology showed dystrophic calcification in all, with no evidence of tumour. Therefore, dystrophic calcification of the fetal myocardium may have a similar appearance to single or multiple rhabdomyomas. This should be considered when counselling parents after detection of masses in the fetal heart, particularly when considering the risk of associated tuberous sclerosis.

Congenital total lipodystrophy and peripheral pulmonary artery stenosis

Multiple peripheral pulmonary artery stenoses were detected in three patients with congenital generalised lipodystrophy. This association, which has not been described before, may be clinically important in patients with lipodystrophy who present with impaired exercise tolerance or heart murmurs.

Laser valvotomy with balloon valvoplasty for pulmonary atresia with intact ventricular septum: five years' experience

OBJECTIVE

To assess immediate and medium term results of transcatheter laser valvotomy with balloon valvoplasty in selected infants with pulmonary atresia and intact ventricular septum.

DESIGN

Prospective study.

SETTING

Tertiary cardiac unit.

PATIENTS

All infants with pulmonary atresia and intact septum with no more than minor tricuspid valve hypoplasia referred between November 1990 and June 1995. Laser valvotomy was attempted in nine infants of median age 4-5 days and median weight 3.6 kg.

INTERVENTION

The pulmonary valve was perforated using a 0.018 inch fibreoptic guidewire attached to a NdYag laser and introduced through a catheter positioned beneath the valve. After perforation the valve was dilated with progressively larger balloons.

MAIN OUTCOME MEASURES

Successful laser valvotomy and balloon dilatation, complications, pulse oximetry, right ventricular outflow velocities, and need for surgical treatment.

RESULTS

Valvotomy was successful in all but one case, the failure being due to laser breakdown. After perforation the valve was dilated to 6-8 mm diameter. Prostaglandin E was withdrawn immediately in six of the eight duct dependent infants, and 28 and 49 days later in two. No patient required an aortopulmonary shunt. Two patients had repeat valvoplasty at 20 days and three months of age, respectively; one required infundibular resection and closure of the atrial septum at age four and one is awaiting similar treatment.

CONCLUSIONS

Laser valvotomy with balloon valvoplasty is safe and effective treatment for selected patients with pulmonary atresia and intact ventricular septum and should be considered as first line treatment in place of surgical valvotomy.

Right ventricular outflow stent implantation: an alternative to palliative surgical relief of infundibular pulmonary stenosis

OBJECTIVE

Preliminary assessment of the use of stents for palliative relief of right ventricular infundibular stenosis as an alternative to palliative surgical ventricular outflow enlargement.

DESIGN

Descriptive clinical study.

PATIENTS

Four patients with right ventricular outflow obstruction, aged between 2 and 15 years. One had had previous palliative surgery for pulmonary atresia, one had hypoplastic pulmonary arteries after palliative surgery for tetralogy of Fallot, one had multiple congenital abnormalities, and one had hypertrophic cardiomyopathy.

SETTING

Tertiary paediatric cardiac centre.

METHODS

After initial echocardiographic diagnosis the extent of right ventricular outflow obstruction was assessed by angiography. Balloon expandable stainless steel stents (Johnson & Johnson) were deployed in the right ventricular infundibulum.

MAIN OUTCOME MEASURES

Improvement in right ventricular outflow assessed by ventriculography and change in right ventricular/ left ventricular pressure ratio, change in systemic oxygen saturation, freedom from arrhythmias, and sustained improvement in echocardiographic indices of obstruction.

RESULTS

Mean right to left ventricular pressure ratio fell from 0.95 to 0.35 in the three patients with intact ventricular septum. Oxygen saturation increased from 76% to 91% in the patient with tetralogy. No arrhythmias were detected. Improvement was maintained at mean follow up of 9.7 months in three cases, but one patient required stent enlargement 17 months later because of neoendothelial proliferation within the stent.

CONCLUSION

Stent implantation provides an effective alternative to palliative surgical enlargement of the right ventricular infundibulum. Neoendothelial proliferation causes reduction in lumen in some cases, but this may respond to redilatation.

Prolonged local infusion of streptokinase in pulmonary artery thrombosis with nephrotic syndrome

A child with nephrotic syndrome presenting with right heart failure and severe pulmonary hypertension due to pulmonary artery thrombus was treated with locally administered streptokinase infusion. Streptokinase infusion was continued for 8 days, eventually leading to complete dissolution of thrombus.

Stenting of stenosed aortopulmonary collaterals: a new approach to palliation in pulmonary atresia with multifocal aortopulmonary blood supply

A patient with complex pulmonary atresia and increasing cyanosis due to stenoses of aortopulmonary collateral vessels improved after implantation of balloon expandable stents into the stenosed vessels. Stent implantation may provide an alternative to surgical palliation in this group of patients.

Ventricular pacing from the coronary sinus of a patient with a Fontan circulation

Permanent pacing of the left ventricle was achieved by transvenous implantation of a steroid-eluting electrode into the coronary sinus in a patient who had undergone a Fontan operation. This approach to endocardial pacemaker implantation is potentially of considerable value in patients who do not have transvenous access to the right ventricle.

Transoesophageal echocardiography in neonates, infants and children: applicability and diagnostic value in everyday practice of a cardiothoracic unit

OBJECTIVE

To determine the applicability of and information obtained by transoesophageal echocardiography in neonates, infants, and children in every day practice of a cardiothoracic unit.

DESIGN

Four month prospective study.

SETTING

Supraregional centre for paediatric cardiothoracic services.

PATIENTS AND METHODS

58 patients aged between four days and 16 years with a wide range of cardiovascular disease underwent transoesophageal echocardiography under sedation or general anaesthetic. One of two paediatric probes (6 or 7 mm diameter), or an adult probe (13 mm in diameter) was used. Whenever possible the investigation was immediately preceded by precordial echocardiography.

MAIN OUTCOME MEASURES

Success, failure, technical difficulties, and complications of probe introduction and, when possible, comparison of the information obtained with that obtained from precordial echocardiography.

RESULTS

Introduction of the probe was successful in 57 of the 58 patients. The only complication encountered was transient bradycardia during manipulation of the probe in a 2.2 kg baby. The adult (13 mm) probe was successfully used in children as small as 7.0 kg. Below this weight a smaller paediatric probe was required. In 56% of cases transoesophageal ultrasound provided information not obtained from the precordial approach. The technique was of particular value perioperatively and in the immediate postoperative period in neonates and infants and in the presence of valve prostheses and the investigation of mediastinal tumours in older children.

CONCLUSIONS

Transoesophageal echocardiography is a valuable additional investigative tool for children of all ages. It is of particular value when acquisition of precordial image is impaired around the time of and after operation and in children with prosthetic valves or mediastinal tumour. Image quality was superior with the adult probe and we recommend the use of this probe unless the patient's weight is below 7 kg, when a paediatric probe allows this technique to be used usefully and safely in babies as small as 2.2 kg.

Anaemia in children following cardiac transplantation: treatment with low dose human recombinant erythropoietin

Anaemia is common in children following cardiac transplantation. In a series of 5 children with anaemia beyond the immediate post-operative period one had a hypochromic, microcytic anaemia which corrected with oral iron. The other four had normochromic, normocytic anaemias unresponsive to iron or folate supplementation and associated with inappropriately low levels of erythropoietin. Subcutaneous administration of low dose human recombinant erythropoietin to these four patients resulted in correction of their anaemia. Our findings suggest that erythropoietin deficiency is an important cause of anaemia in transplant recipients and should be sought in cases of anaemia refractory to conventional haematinic therapy. In cases of proven erythropoietin deficiency, treatment with erythropoietin is effective, acceptable to patients and preferable to repeated blood transfusion.

Stenting of the arterial duct: a new approach to palliation for pulmonary atresia

OBJECTIVE

To assess the possibility of maintaining ductal patency in neonates with complex pulmonary atresia by percutaneous implantation of balloon expandable stents.

PATIENTS

Two duct-dependent neonates with long segment pulmonary atresia, right sided aortic arch, and left sided arterial duct.

RESULTS

Stents with final diameter of 3.5 or 4 mm and initial length of 7 or 15 mm were successfully positioned in the arterial duct. Two stents were required in one child and four in the other in order to stent the entire length of the duct. After the procedures the ducts remained widely patent and arterial oxygen saturations remained above 80%. Complications of the procedures included perforation of a peripheral pulmonary artery and cardiac perforation, both caused by guide wire manipulation. Both babies died suddenly, one at five weeks, and the other at nine days after successful stenting of the duct. Both ducts were patent at necropsy; the exact cause of one death was not clearly defined, but the second seemed to be caused by pneumococcal septicaemia.

CONCLUSIONS

Stenting of the arterial duct is technically feasible. It provides adequate palliation for neonates with pulmonary atresia at least in the short term and it seems to result in balanced, central perfusion of both pulmonary arteries. This preliminary report suggests that this previously untried technique may prove to be a promising and attractive alternative to neonatal aortopulmonary shunt operation.

Severe pulmonary stenosis and interruption of the aortic arch

A case of severe pulmonary stenosis associated with a subpulmonary ventricular septal defect and interruption of the aortic arch is described in a 5-month-old girl. This combination defies explanation by current theories of the development of obstructive abnormalities of the aortic arch secondary to reduced aortic flow during fetal life, and, to the best of our knowledge, is the first reported case with this particular association.

Chorea after cardiopulmonary bypass: exacerbation by captopril

Chorea is a rare complication of major cardiac surgery, which has been related to profound hypothermia and circulatory arrest. We describe a case of choreic syndrome in a child which followed normothermic cardiac bypass and only became apparent clinically when the child was treated with captopril.

Adrenal response in very low birthweight babies after dexamethasone treatment for bronchopulmonary dysplasia

The tetracosactrin stimulation test was used to assess the adrenal responsiveness of 22 very low birthweight babies who had received a three week course of dexamethasone for the treatment of bronchopulmonary dysplasia. Five babies were studied in detail with blood samples taken for cortisol concentrations at 30 minute intervals for four hours. The tests were performed before, during, and after treatment with dexamethasone. A distinctive pattern of cortisol response to tetracosactrin was found among these babies, which was quite unlike that found in older children and adults. Using our pretreatment results as control data we conclude that there is undoubtedly evidence of modest suppression of the adrenal axis during dexamethasone treatment, although there is considerable recovery one month after stopping steroids. Basal cortisol concentrations, however, remained low in some cases, which may indicate the need for temporary corticosteroid replacement during severe illness.

Determination of plasma bicarbonate of neonates in intensive care

Most modern blood-gas analyzers are programmed to use the Henderson-Hasselbalch equation to calculate a value for plasma bicarbonate. It has been suggested, however, that among acutely ill patients, including newborns, these calculated values may be at variance with measured total CO2. To assess the clinical significance of such errors, we compared calculated bicarbonate with measured total CO2 in 79 blood samples from 40 babies in intensive care. The calculated bicarbonate values consistently exceeded the measured values by about 1.5 mmol/L. Of the errors, 94% were within the range -10% to +20%. When the systematic bias was removed, calculated and measured bicarbonate values agreed within +/- 3.30 mmol/L in 95% of cases. Because calculated values can be obtained much more quickly and frequently than laboratory measurements, we believe that these limits are clinically acceptable.

Determination of plasma bicarbonate of neonates in intensive care

Most modern blood-gas analyzers are programmed to use the Henderson-Hasselbalch equation to calculate a value for plasma bicarbonate. It has been suggested, however, that among acutely ill patients, including newborns, these calculated values may be at variance with measured total CO2. To assess the clinical significance of such errors, we compared calculated bicarbonate with measured total CO2 in 79 blood samples from 40 babies in intensive care. The calculated bicarbonate values consistently exceeded the measured values by about 1.5 mmol/L. Of the errors, 94% were within the range -10% to +20%. When the systematic bias was removed, calculated and measured bicarbonate values agreed within +/- 3.30 mmol/L in 95% of cases. Because calculated values can be obtained much more quickly and frequently than laboratory measurements, we believe that these limits are clinically acceptable.