Proximal Branch Pulmonary Artery Research Articles

Infected right ventricular outflow tract pseudoaneurysm in an infant with tetralogy of Fallot: Successful palliation using a Gore VBX® covered stent

ABSTRACT Pseudoaneurysm formation within the right ventricular outflow tract (RVOT) is a rare but serious complication following cardiac surgeries involving the RVOT. This report presents the case of a 3-month-old, 4 kg infant with tetralogy of Fallot and pulmonary atresia, previously treated with ventricular septal defect closure and right ventricle (RV)–pulmonary artery homograft placement. The patient presented critically ill with septic shock and suprasystemic RV pressure. A high-risk surgical approach was averted through the endovascular exclusion of the pseudoaneurysm using a Gore VBX® balloon expandable covered stent, in addition to stenting of bilateral proximal branch pulmonary arteries to alleviate RV hypertension. This case underscores the multifactorial nature of RVOT pseudoaneurysm formation and the importance of a high index of suspicion for diagnosis. Management options, including surgical and transcatheter strategies, are discussed, focusing on the successful use of a covered stent for stabilization in a critically ill patient.

Mid-term outcomes of Contegra implantation for the reconstruction of the right ventricular outflow tract to proximal branch pulmonary arteries: Japan multicentre study.

To reveal the mid-term outcomes of Contegra implantation for the reconstruction of the right ventricular outflow tract to proximal branch pulmonary arteries in a multicentre study. Between April 2013 and December 2019, 178 Contegra conduits were implanted at 5 Japanese institutes. The median age and body weight at operation were 16 months (25th-75th percentile: 8-32) and 8.3 kg (6.4-10.6). Sixteen patients were neonates (9.0%). Selected conduit sizes were 12 mm in 28 patients (15.7%), 14 mm in 67 patients (37.6%), 16 mm in 66 patients (37.1%), 18 mm in 5 patients (2.8%) and <12 mm in 12 patients (6.7%). Fifty-six grafts (31.4%) were ring supported. Proximal branch pulmonary arteries were concomitantly augmented in 85 patients (47.5%). Follow-up was completed in all patients and the median follow-up period was 3.1 years (1.3-5.1). The overall, conduit explantation-free and conduit infection-free survival rates at 5 years were 91.3%, 71.0% and 83.7%, respectively. Infection (P = 0.009) and common arterial trunk (P = 0.024) were risk factors for explantation. Conduit durability was shorter in smaller one (P < 0.001). Catheter interventions (for conduit to proximal branch pulmonary artery)-free survival rates at 5 years was 52.9%; however, need for catheter interventions was not a risk factor for conduit explantation. Mid-term outcomes of reconstruction of the right ventricular outflow tract to the proximal branch pulmonary arteries with Contegra were acceptable. The need for explantation over time was higher in smaller conduits. Conduit infection was a strong risk factor for conduit explantation. Frequently and repeated catheter interventions effectively extended the conduit durability.

Tetralogy of Fallot with absent pulmonary valve syndrome: A 34-year African single centre experience

Background: Absent pulmonary valve syndrome (APVS) is most commonly associated with Tetralogy of Fallot (TOF). TOF with APVS is characterised by features of TOF with either rudimentary ridges or complete absence of pulmonary valve tissue. This is often associated with varying degrees of pulmonary stenosis and severe pulmonary regurgitation with massive dilatation of the proximal branch pulmonary arteries, causing compression of the tracheobronchial tree. Hence, respiratory symptoms are a common presenting feature. Methods: Cases of TOF with APVS were extracted from the paediatric cardiology database at Chris Hani Baragwanath Academic Hospital (CHBAH) for January 1981 - April 2016. Results: A total of 15 patients with TOF and APVS were seen at CHBAH over the 34-year study period. TOF with APVS comprised 3% of all TOF patients. Ten (67%) patients presented before 1 year of age. The majority of patients (67%) had respiratory symptoms as their cause of presentation, of which 6 (40%) were infants. Fourteen (93%) patients were described to have the characteristic to-and-fro murmur at presentation. Five patients (33%) were suspected of having 22q11.2 deletion syndrome, but only 4 were tested and 2 were found to be positive. A third of patients underwent surgical intervention and 4 of the 15 patients (27%) were known to be alive at 10 years of age. Conclusions: TOF with APVS compromised 3% of all TOF patients, correlating with the literature. It is associated with the 22q11.2 deletion syndrome and was suspected in 33% of patients. TOF with APVS should be strongly considered in a child less than 1 year presenting with respiratory symptoms and a characteristic to-andfro murmur.

Bifurcating stents in the pulmonary arteries: A novel technique to relieve bilateral branch pulmonary artery obstruction.

Balloon angioplasty and stent placement in close proximity to the bifurcation of the branch pulmonary arteries can be challenging. Multiple approaches have been previously described, though none of these approaches both treats bilateral proximal branch pulmonary artery stenosis and provides an anchor for a transcatheter pulmonary valve replacement. We report a novel approach that involves serial stent placement and balloon dilation through the struts of the stent in each pulmonary artery, along with balloon expansion of the proximal portion of the stents to the diameter of the main pulmonary artery. In the two cases we describe, this strategy resulted in significant relief of branch pulmonary artery obstruction without compromising the anatomy of the main pulmonary artery segment. This technique can be an effective way to alleviate stenoses of the bilateral proximal branch pulmonary arteries and provides a landing zone for a future transcatheter pulmonary valve.

EComment. Paradigm shift in surgery for massive pulmonary embolism: If not now then when?

This retrospective study by Zarrabi et al. adds to the growing repository of contemporary evidence regarding the safety and efficacy of surgical embolectomy for massive and submassive pulmonary embolism [1]. The authors highlight the potential for chronic thromboembolic pulmonary hypertension, an important but often overlooked sequelae of suboptimal therapy which may result following anticoagulation only, or catheter directed thrombolysis due to incomplete recanalization. The significant consistent reduction in pulmonary arterial systolic pressures reported on serial studies immediately before and after surgery and on follow-up is most encouraging. Despite improved outcomes, a surgical embolectomy largely remains a second line or last resort alternative therapy, perhaps burdened by historical outcomes. However, with the increased availability of cardiopulmonary bypass support and more detailed imaging (computed tomography and transoesophageal echocardiography), a surgical embolectomy should feature early in the treatment algorithm of any patient with a large volume central thrombus burden in the main pulmonary artery or proximal branch pulmonary arteries. Surgery should also be considered for the haemodynamically stable patient who may have features of impending right ventricular dysfunction, a known prognosticator for an embolism-related early (in-hospital or 30 day) death [2]. In carefully selected patients, an early surgical embolectomy may offer the best opportunity to rapidly and completely reperfuse the pulmonary arterial vasculature, thereby avoiding potential future complications such as chronic thromboembolic pulmonary hypertension. Conflict of Interest: None declared

Transcatheter closure of patent ductus arteriosus and ductus in children

In normal cardiovascular development, the proximal portions of the sixth pair of embryonic aortic arches persist as the proximal branch pulmonary arteries and the distal portion of the left sixth arch persists as the ductus arteriosus, connecting the main pulmonary trunk with the left dorsal aorta. In full-term infants, postnatal closure of the ductus is effected in two phases: smooth muscle constriction produces ‘‘functional’’ closure of the lumen of the ductus within 18 to 24 hours after birth; and ‘‘anatomical’’ occlusion of the lumen occurs over the next few days or weeks. Over the past two decades, transcatheter occlusion of patent ductus arteriosus has evolved to be the procedure of choice. Several devices have been used to close patent ductus arteriosus in children. Coils are generally used for small PDAs and occluding devices for larger PDAs.

Bilateral Branch Pulmonary Artery Melody Valve Implantation for Treatment of Complex Right Ventricular Outflow Tract Dysfunction in a High-Risk Patient

Percutaneous pulmonary valve replacement is one of the most important advancements in the field of interventional cardiology in the past decade.1,2 However, currently available technologies are not applicable to patients with oversized right ventricular outflow tracts (RVOTs), especially when there is concomitant proximal branch pulmonary artery (PA) stenosis. This combination commonly is encountered in clinical practice. Our group has a longstanding interest in these complex patients, and we have recently published preclinical studies describing the feasibility and short-term effects of implanting 2 Melody valves—1 into each proximal branch PA—in an ovine model of postoperative pulmonary insufficiency and dilated RVOT.3 This report describes bilateral branch PA Melody valve implantation to treat complex RVOT dysfunction in a high-risk patient. At presentation, the patient was a 27-year-old woman with a complex medical history. Her cardiac condition was double-outlet RV with pulmonary stenosis and interrupted inferior vena cava with azygos continuation to a left-sided superior vena cava. She was status post-Waterston shunt as an infant, with subsequent closure of the ventricular septal defect and patch augmentation of the RVOT. Three months before catheterization, the patient presented to her cardiologist with symptoms of progressive activity intolerance over the past year. She was oxygen dependent and on long-term continuous positive airway pressure therapy. Comorbidities included VATER and Klippel-Feil syndromes, renal agenesis, Mullerian agenesis, gout, and obesity. The patient had undergone multiple spinal fusion and Harrington rod procedures as well as repair of tracheoesophageal …

Modified Repair of Truncus Arteriosus to Maintain Pulmonary Artery Architecture

Neonatal surgical repair for truncus arteriosus historically involves removing the pulmonary arteries from the truncal root, closing the ventricular septal defect, and creating right ventricular to pulmonary artery continuity. Unfortunately, early reintervention is frequently required for conduit failure and proximal branch pulmonary artery stenosis. We present a technique that preserves the pulmonary artery architecture, keeping the pulmonary arteries in their native position. This technique has been applied to 16 patients and appears to decrease proximal branch pulmonary artery stenosis, thereby extending conduit longevity and increasing the freedom from early reintervention.

How We Approach Peripheral Pulmonary Stenosis in Williams-Beuren Syndrome

Williams-Beuren syndrome is associated with supravalvar aortic stenosis and peripheral pulmonary artery stenosis in the majority of affected individuals. Among patients in whom surgery for supravalvar aortic stenosis is contemplated, stenosis of the branch pulmonary arteries is common. For asymptomatic patients with subsystemic right ventricular pressure, the natural history is favorable and no intervention is necessary. For patients with important proximal branch pulmonary artery, stenoses patch arterioplasty can be accomplished at the time of surgery for supravalvar aortic stenosis. For patients with important peripheral pulmonary stenosis, preoperative catheter-based therapy is indicated. Surgical repair of peripheral pulmonary stenosis is indicated when preoperative intervention is unsuccessful and can include a combination of patch arterioplasty as well as intraoperative application of catheter-based techniques. This report will address the approach to this lesion with catheter-based approaches, surgical approaches, and their combination.

Dual-source Computed Tomography in Paediatric Congenital Heart Disease Patients – Combination of Low-kilovoltage Protocols and Ultravist Injection

In the clinical management of patients with complex congenital heart disease (CHD), accurate 3D evaluation of their morphological conditions is critical. 3D imaging should demonstrate the shape and spatial relation of great arteries, proximal branch pulmonary arteries and anomalous pulmonary venous or systemic connections, and eventually coronary artery course. 3D information on extra-cardiac morphological characteristics may determine the choice and the route of surgical intervention.

Patent Ductus Arteriosus

The patent ductus arteriosus (PDA) is a vascular structure that connects the proximal descending aorta to the roof of the main pulmonary artery near the origin of the left branch pulmonary artery. This essential fetal structure normally closes spontaneously after birth. After the first few weeks of life, persistence of ductal patency is abnormal. The physiological impact and clinical significance of the PDA depend largely on its size and the underlying cardiovascular status of the patient. The PDA may be “silent” (not evident clinically but diagnosed incidentally by echocardiography done for a different reason), small, moderate, or large. Regardless of the size, complications may arise, and it is important for both pediatric and adult cardiologists to have an understanding of the pathophysiology, clinical implications, and management of PDA. The ductus arteriosus is a normal and essential fetal structure that becomes abnormal if it remains patent after the neonatal period. In normal cardiovascular development, the proximal portions of the sixth pair of embryonic aortic arches persist as the proximal branch pulmonary arteries, and the distal portion of the left sixth arch persists as the ductus arteriosus, connecting the left pulmonary artery with the left dorsal aorta (Figure 1). Normally, the distal right sixth aortic arch loses its connection to the dorsal aorta and degenerates. This transformation is complete by 8 weeks of fetal life. Figure 1. Schematic of embryonic aortic arch system. The 6 pairs of embryonic aortic arches are demonstrated (left-sided arches are numbered). The portions that normally involute are indicated by broken lines. The distal left sixth embryonic arch normally persists and becomes the PDA, connecting the left pulmonary artery to the proximal descending aorta. The right distal sixth arch normally involutes, as does the eighth segment of the right dorsal aorta (*), which results in a leftward aortic …

Fetal oxygenation and Doppler ultrasonography of cardiovascular hemodynamics in a chronic near-term sheep model

We hypothesized that a decrease in fetal oxygenation without acidemia in a near-term fetal sheep leads to cardiovascular hemodynamic changes that are detectable by Doppler ultrasonography. Twelve ewes and fetuses were instrumented at 112 to 127 days of gestation. After a 5-day recovery period, experiments were performed with general anesthesia. Uterine and placental volume blood flows and fetal arterial and venous blood pressures were measured. Fetal cardiovascular hemodynamics was assessed by Doppler ultrasonography. All the measurements were performed at baseline, during fetal hypo-oxygenation, and at recovery phase. A drop in fetal Po2 was related to increased (P < .05) weight-indexed right ventricular and combined cardiac outputs and proximal branch pulmonary artery pulsatility index values. The increase in proximal branch pulmonary artery pulsatility index values correlated (R = .59; P < .05) with the decrease in fetal oxygen saturation. In the aortic isthmus, the time-velocity integral ratio between antegrade and retrograde blood flow components decreased (P < .05) when fetal Po2 dropped. During decreased fetal oxygenation Doppler ultrasonography demonstrated increased fetal cardiac output and pulmonary arterial vascular impedance and a relative increase in the retrograde blood flow component in the aortic isthmus.

Is cardiac catheterization a prerequisite in all patients undergoing bidirectional cavopulmonary anastomosis?

Traditionally, all patients undergo cardiac catheterization before bidirectional cavopulmonary anastomosis (BCPA). The purpose of this study was to determine if preoperative catheterization is necessary when echocardiographic parameters appear favorable. A retrospective review was performed of all patients who underwent BCPA (n = 142) between February 1996 and May 2001. Echocardiographic criteria defining a favorable BCPA candidate included good ventricular function, moderate or less atrioventricular and semilunar valve regurgitation, absence of ventricular outflow tract obstruction, normal proximal branch pulmonary artery (PA) size, and low PA pressures estimated by PA band gradient or systemic PA shunt velocity. The median age at operation was 7 months (range: 2-11) and weight was 6.2 kg (range: 2.7-7.1). There were 73 unfavorable candidates. Patients with hypoplastic left heart syndrome (n = 23) and pulmonary atresia with intact septum (n = 15) predominated among the unfavorable group. All patients were catheterized. This provided additional information on PA pressures in 3 patients in the favorable group but did not defer operation or influence outcome (no mortality, prolonged pleural drainage, or longer intensive care department stay). All 3 patients are alive at a mean follow-up of 51 months. The 30-day mortality was 2% (4 of 151 patients), all in the unfavorable group. Overall, 20 patients (13%) required arterioplasty of PAs at the time of BCPA. BCPA can be performed with a low risk of morbidity and mortality in a wide range of patients. By using commonly acquired echocardiographic parameters, a low-risk subgroup of patients can be identified who can safely avoid preoperative cardiac catheterization.

Three-dimensional helical computed tomographic angiography in neonates and infants with complex congenital heart disease

Background For the clinical management of patients with complex congenital heart disease (CHD), accurate evaluation of their morphologic conditions is critical. Three-dimensional (3D) helical computed tomography (CT) angiography has been used to assess the vascular system in adult patients; the indication for complex CHD, especially in the neonatal period, has not yet been defined. Therefore the purposes of our study were to determine the quality and limitations of current 3D helical CT angiography for neonates and infants with complex CHD and to assess the clinical utility of this technique. Methods and Results 3D helical CT angiography was performed in 17 patients with various types of complex CHD. Their median age was 41 days (range 3 days to 9 months), and mean body weight was 3.6 kg (range 2.2 to 8.5 kg). All 3D images were produced with the 3D reconstruction algorithm of shaded-surface display. Oral sedation was required in only 4 infants during the procedure. 3D helical CT angiography clearly demonstrated the shape and spatial relation of great arteries, proximal branch pulmonary arteries, anomalous pulmonary venous connections, the patent ductus arteriosus, and a shunt. The 3D information of extracardiac morphologic characteristics and 3D anatomic relation of each extracardiac structure were easily recognized by this imaging process. However, intracardiac structure could not be visualized because of blurred and/or unclear edges of the ventricular wall caused by respiratory movement. Conclusions 3D helical CT angiography represents an important additional diagnostic tool and may become an alternative method to angiography or other noninvasive techniques used in the evaluation of extracardiac anomalies in neonates and infants with complex CHD.

Tetralogy of Fallot with absent pulmonary valve: Echocardiographic morphometric features of the right-sided structures and their relationship to presentation and outcome

Respiratory symptoms in tetralogy of Fallot with absent pulmonary valve are believed to be due to bronchial compression secondary to dilated pulmonary arteries; however, not all patients are born compromised. Echocardiographic morphometry of the right-sided structures was investigated to determine the possible relationship between anatomy and clinical presentation. Twenty-five patients were identified, and 15 had preoperative echocardiograms. Patients were divided into two groups: those with respiratory distress (group I, n = 9) and those without (group II, n = 6). No difference was noted in branch pulmonary artery diameters between groups; however, the pulmonary valve/aortic valve ratio, reflecting the dimension of the narrowest pathway from the right ventricle, was larger in group I (0.74 ± 0.15 versus 0.60 ± 0.07, p < 0.05). Pulmonary valve diameter correlated with main and right pulmonary artery diameters. We conclude that patients with tetralogy of Fallot with absent pulmonary valve and respiratory compromise have a greater pulmonary valve/aortic valve ratio but do not have greater dilatation of proximal branch pulmonary arteries. This suggests that the pathophysiology is not due solely to compression of the bronchi but is also related to the blood flow dynamics in the pulmonary vessels. (J Am Soc Echocardiogr 1997;10:556-61.)

Stenting of the arterial duct combined with banding of the pulmonary arteries and atrial septectomy or septostomy: a new approach to palliation for the hypoplastic left heart syndrome.

To assess the feasibility of pulmonary artery banding, atrial septectomy or septostomy, and percutaneous stenting of the arterial duct in babies with the hypoplastic left heart syndrome. Four infants with hypoplastic left heart syndrome. Two supraregional paediatric cardiac centres. Ductal patency was maintained initially with prostaglandin E. Banding of the proximal branch pulmonary arteries was performed through a median sternotomy and open atrial septectomy was performed if balloon septostomy was not. Stainless steel stents (Johnson & Johnson) mounted in a balloon catheter were implanted into the arterial duct under radiographic control and expanded to a diameter of approximately 8 mm, prostaglandin treatment was then stopped. All the patients survived the immediate postoperative period and maintenance of wide ductal patency was achieved in three of the four patients by stent implantation. Two weeks after the procedure two babies died of right ventricular failure and respiratory infection: some distal ductal constriction had occurred in one where the stent was not quite sufficiently distally placed. One child was discharged home 15 days after treatment and was well at follow up at age 16 weeks and one was stable but required diuretic therapy five weeks after the procedure. This new approach is technically feasible. At least in the short term it seems to offer hope of effective palliation for the hypoplastic left heart syndrome and it warrants further study.