Ductal-dependent Pulmonary Blood Flow Research Articles

Stenting the arterial duct in neonates and infants with congenital heart disease and duct‐dependent pulmonary blood flow: A multicenter experience of an evolving therapy over 18 years

The primary aim of this multi-institutional study was to describe our 18-year experience of ductal stenting (DS) in infants with a duct-dependent pulmonary circulation. The secondary aim sought to identify a subgroup of patients who may benefit the most using this evolving technique. No study has examined the extraordinary evolution of this promising therapy over the last two decades. Between 1991 and 2009, 65 neonates and infants (39 male, 60%) underwent cardiac catheterization for DS in 3 participating centres. Patients were divided according to whether DS was attempted between 1991-2000 (Group 1, n = 20) or between 2001-2009 (Group 2, n = 45). DS was successful in 52/65 (80%) patients. DS outcome was associated with ductal morphology and cardiac diagnosis. DS failed more often in patients with univentricular physiology and tortuous duct morphology (p < 0.001). Most patients undergoing DS in Group 2 had pulmonary atresia with intact ventricular septum (PAIVS) (p < 0.001). DS was successful in 94% of these patients. Groups differed significantly in diameter and length of first implanted stent (p < 0.001), implanting additional stent (p < 0.001), and occurrence of complications (p = 0.033). Freedom from re-intervention for the 52 patients was 92.3%. No procedure-related mortality occurred. The technical aspects and clinical application of percutaneous DS has changed in the last two decades. DS has become a practical and safe therapy in a subgroup of neonates with ductal-dependent pulmonary blood flow.

Management of newborns with duct-dependent congenital heart disease with prostaglandin E1 – Slovenian guidelines

Background: Early recognition of duct-dependent congenital heart disease in newborns with duct-dependent pulmonary or systemic blood flow or transposition of the great arteries is critical for early introduction of prostaglandin E1 (PGE1), which allows stabilization of the newborn till cardiac catheterization or surgical intervention. Indications for PGE1, management of newborns with duct-dependent congenital heart disease and interventions in case of side effects of PGE1 are reviewed. Conclusions: It is critical to start with PGE1 infusion as soon as we clinically suspect ductdependent congenital heart disease. With this approach, morbidity and mortality of newborns with congenital heart disease is significantly reduced.

Diagnosis and management of tritruncal heart in an infant

taneous abortions. The management strategy of the patients herein was flexible due to unpredictable pathologic and clinical evolution of the tumor. At birth, PGE1 therapy and adequate atrial-level shunting, requiring atrial septostomy in 1 patient, were necessary due to univentricular physiology with ductal-dependent pulmonary blood flow. Unexpectedly, both neonates presented severe pulmonary hypertension, only partially responsive to intravenous and inhaled pulmonary vasodilators. Prematurity and persistent fetal circulation were thought to be responsible; only after postmortem diagnosis of patient 2 did we identify recurrent pulmonary embolism due to tumor calcification and fragmentation. Retrospectively, therefore, the rationale for delaying surgical excision (low body weight, prematurity, expectation of spontaneous regression) appears unjustified. On the contrary, intracardiac masses with clinicopathologic features inconsistent with cardiac rhabdomyoma must be referred for early surgical excision to allow for diagnosis and prevention of life-threatening embolism. Furthermore, when fetal-type rhabdomyoma is identified in a child, genetic counseling must consider the possibility of occurrence of the tumor in future pregnancies and should advise in utero echocardiographic screening. In the case of diagnosis, however, any decision to interrupt pregnancy should take into consideration the fact that radical resection in infancy is feasible and no association with tuberous sclerosis has been reported.

Right Ventricular Outflow Tract Transannular Patch Placement without Cardiopulmonary Bypass

In children with pulmonary atresia not amenable to initial complete correction, antegrade pulmonary blood flow can be established with surgical right ventricular outflow tract (RVOT) patch enlargement. An 11-year experience with RVOT transannular patch (TAP) augmentation without the use of cardiopulmonary bypass (off-pump) is reported. From March 1993 to October 2004, off-pump surgical RVOT enlargement with a TAP was attempted in all patients in whom a concurrent procedure that required bypass was not required. The procedure was performed with cardiopulmonary bypass standby. Twenty-two consecutive patients in whom this procedure was attempted were reviewed. Twenty of 22 patients tolerated off-pump TAP placement. In 2 patients with ductal-dependent pulmonary blood flow, off-pump TAP placement was not tolerated. Adequate antegrade pulmonary blood flow was achieved in all patients without operative mortalities or complications. There was one death in the postoperative period from myocardial ischemia secondary to right ventricular-dependent coronary circulation. Transannular RVOT patch augmentation can be performed safely and effectively without cardiopulmonary bypass.

The neonate with suspected congenital heart disease.

Congenital heart disease (CHD) occurs in 8 per 1000 live births, with approximately one third of these neonates requiring intervention in the first month of life. Neonates with respiratory distress, cyanosis, feeding difficulties, low cardiac output, or dysmorphic syndromes commonly have CHD. Clinical suspicion increases in a symptomatic infant with a heart murmur, but the presence or absence of a murmur does not assure either the presence or absence of significant congenital heart disease. Infants suspected to have CHD may be divided into premature and term infants, as well as infants with duct-dependent pulmonary blood flow, infants with duct-dependent systemic blood flow, and infants with unrestricted pulmonary blood flow. This article will also address the specialized clinical situations of total anomalous pulmonary venous return, transposition of the great arteries, and hypoplastic left heart syndrome with intact atrial septum.

Fate of the stented arterial duct.

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

Conversion of complex neonatal Ebstein's anomaly into functional tricuspid or pulmonary atresia.

Ebstein's anomaly, due to failure of delamination of one or more leaflets of the tricuspid valve (TV), is associated with varying degrees of tricuspid regurgitation (TR) and dysplasia of the right ventricle (RV). Although refinement of tricuspid valvuloplasty and plication techniques have opened the way to a satisfactory outlook for the majority of older children and adults, Ebstein's anomaly presenting at neonatal age, secondary to ineffective forward flow into the pulmonary and systemic circulation, has a reported mortality rate of as high as 75%. In order to improve the dismal outcome in neonatal Ebstein's anomaly, we have strived for early univentricular palliation. Univentricular repair was performed in five neonates (median age 5 days; range 2-14 days) with Ebstein's anomaly, ductal dependent pulmonary blood flow, severe TR, absence of forward flow across the pulmonary valve, and small left ventricular (LV) area due to right-to-left bowing of the ventricular septum and ineffective LV loading (median indexed LV area 10.5 cm2/m2). In addition, two neonates had moderate pulmonary regurgitation (PR), one with additional pulmonary stenosis. In all patients, the indexed area of the combined right atrium and atrialized RV was greater than that of the combined functional RV, left atrium, and left ventricle (median 22.0 and 20.8 cm2/m2, respectively). The median preoperative systemic oxygen tension was 35 mmHg and the median pH 7.28. Repair consisted of TV closure with a pericardial patch (with the coronary sinus draining into the RV) (n = 3) or, in the presence of PR, resection of the dysplastic TV and division and oversewing of the main pulmonary artery (n = 2), as well as excision of the atrial septum, resection of redundant right atrial wall, and construction of an aortopulmonary shunt (n = 5). The median indexed LV area increased from 10.5 to 18.8 cm2/m2 as a result of more effective loading of the left ventricle. There was no intraoperative or late mortality. The patients were extubated at a median of 7 days postoperatively. At discharge, the median systemic oxygen tension was 46 mmHg. In all five patients, at 6, 7, 10, 12 and 16 weeks of age, a bidirectional cavopulmonary anastomosis has been constructed. In neonates with Ebstein's anomaly and ductal dependent pulmonary blood flow, rational palliation consists of the surgical creation of tricuspid atresia or, in the additional presence of PR or pulmonary stenosis, the creation of pulmonary atresia. These procedures may result in effective LV decompression and more effective volume loading of the left ventricle with increase of systemic output and improved clinical outcome.

Critical pulmonary valve stenosis in the neonate: A technique to facilitate balloon dilation

Critical pulmonary valve stenosis associated with ductal dependent pulmonary blood flow is rare, accounting for a small proportion of all infants undergoing balloon dilatation. 1 Valvuloplasty in these infants may be technically difficult and at times impossible due to inability to traverse the critically stenotic valve. Previous investigators have described a gradational approach whereby balloon catheters of increasing diameter (2, 4, 6, 8 and 10 mm) are sequentially advanced and inflated across the valve relieving the obstruction. 2 This approach, however, is time consuming and subjects the infant to prolonged fluoroscopy exposure. We have developed a valvuloplasty technique in the neonate with critical pulmonary valve stenosis which shortens fluoroscopy time and facilitates catheter advancement across the critically stenotic valve.

Determinants for outcome of hypoplastic right ventricle with duct-dependent pulmonary blood flow presenting in the neonatal period

SummaryA retrospective study was undertaken of patients with hypoplastic right ventricles, either with pulmonary atresia and intact ventricular septum or critical pulmonary valvar stenosis, and duct-dependent pulmonary blood flow who were investigated at the Royal Brompton Hospital between January 1976 and December 1990. The diagnosis was made on the basis of at least one diagnostic method (cross-sectional echocardiography, cardiac catheterization and angiography, or autopsy). Of the patients, 56 (82%) were found to have an imperforate pulmonary valve or infundibulum (pulmonary atresia), while 12(18%) had critical pulmonary valvar stenosis. The ratio of the diameters of the tricuspid and mitral valvar orifices was measured angiographically during diastole, and the right ventricle was analyzed according to the presence or overgrowth of the inlet, apical trabecular and outlet components. A correlation was made between the severity of the disease and the outcome. The overall mortality was 53% when those not undergoing any surgery were excluded, and significant differences were found between the group dying and those who survived. The incremental risk factors for death were a ratio between the diameter of the tricuspid and mitral valves of less than 0.6; the presence of fistulous communications with the coronary arteries; and obliteration of the apical trabecular component of the right ventricle. There was no significant difference between the group with pulmonary valvar atresia and the group with critical stenosis of the pulmonary valve.

Pharmacologic dilatation of the ductus arteriosus with prostaglandin E1 in infants with congenital heart disease.

Prostaglandin E1 (PGE1) has been used for successful palliation in nine infants with congenital heart disease. Seven patients had pulmonary atresia with ductal-dependent pulmonary blood flow. In this group, systemic O2 saturation increased from a mean value of 45% to 79% after infusion of PGE1, and surgical palliation was successfully done with the infants in stable condition, without hypoxemia or acidemia. An additional patient with coarctation of the aorta had marked ductal dilatation after PGE1 infusion as indicated by umbilical artery pulse pressure. The coarctation was repaired, with the infant in stable condition. The final patient had neonatal tricuspid insufficiency with right to left atrial shunting. Systemic O2 saturation was improved after PGE1 infusion, though the ductus was closed. The improved oxygenation was believed to be due to a reduction in pulmonary vascular resistance by PGE1. Prostaglandin E1 provides a powerful new tool for palliation of critical congenital heart disease in infants whose ductal constriction can markedly influence their clinical status.