Stent implantation and balloon angioplasty for treatment of branch pulmonary artery stenosis in children

The effects of percutaneous branch pulmonary artery interventions on exercise capacity, lung perfusion, and right ventricular function in biventricular CHD: a systematic review

BACKGROUND

Branch pulmonary artery stenosis is common after surgical repair in patients with biventricular CHD and often requires reinterventions. However, (long-term) effects of percutaneous branch pulmonary artery interventions on exercise capacity, right ventricular function, and lung perfusion remain unclear. This review describes the (long-term) effects of percutaneous branch pulmonary artery interventions on exercise capacity, right ventricular function, and lung perfusion following PRISMA guidelines.

METHODS

We performed a systematic search in PubMed, Embase, and Cochrane including studies about right ventricular function, exercise capacity, and lung perfusion after percutaneous branch pulmonary artery interventions. Study selection, data extraction, and quality assessment were performed by two researchers independently.

RESULTS

In total, 7 eligible studies with low (n = 2) and moderate (n = 5) risk of bias with in total 330 patients reported on right ventricular function (n = 1), exercise capacity (n = 2), and lung perfusion (n = 7). Exercise capacity and lung perfusion seem to improve after a percutaneous intervention for branch pulmonary artery stenosis. No conclusions about right ventricular function or remodelling, differences between balloon and stent angioplasty or specific CHD populations could be made.

CONCLUSION

Although pulmonary artery interventions are frequently performed in biventricular CHD, data on relevant outcome parameters such as exercise capacity, lung perfusion, and right ventricular function are largely lacking. An increase in exercise capacity and improvement of lung perfusion to the affected lung has been described in case of mild to more severe pulmonary artery stenosis during relatively short follow-up. However, there is need for future studies to evaluate the effect of pulmonary artery interventions in various CHD populations.

The treatment dilemma in adult patients with peripheral pulmonary artery stenosis of diverse etiologies

Background

Peripheral pulmonary artery stenosis (PPAS) is a rare and underdiagnosed phenomenon that is reported infrequently in adult patients. Most patients with PPAS have concomitant congenital heart diseases, a history of palliative surgical therapies during childhood, or syndromic characteristics. Acquired cases are rare, and they are underestimated in adulthood and managed inappropriately.

Case presentation

This case series describes 3 adult patients with PPAS of diverse etiologies and discusses their underlying causes, diagnostic modalities, and treatment strategies.

Conclusions

In patients with PPAS, sufficient heed should be paid to endovascular interventions such as balloon dilation and primary or bailout stenting, not least vis-à-vis the type and size of balloons or stents as well as complications and preventive strategies.

Pulmonary artery and lung parenchymal growth following early versus delayed stent interventions in a swine pulmonary artery stenosis model

OBJECTIVES

Compare lung parenchymal and pulmonary artery (PA) growth and hemodynamics following early and delayed PA stent interventions for treatment of unilateral branch PA stenosis (PAS) in swine.

BACKGROUND

How the pulmonary circulation remodels in response to different durations of hypoperfusion and how much growth and function can be recovered with catheter directed interventions at differing time periods of lung development is not understood.

METHODS

A total of 18 swine were assigned to four groups: Sham (n = 4), untreated left PAS (LPAS) (n = 4), early intervention (EI) (n = 5), and delayed intervention (DI) (n = 5). EI had left pulmonary artery (LPA) stenting at 5 weeks (6 kg) with redilation at 10 weeks. DI had stenting at 10 weeks. All underwent right heart catheterization, computed tomography, magnetic resonance imaging, and histology at 20 weeks (55 kg).

RESULTS

EI decreased the extent of histologic changes in the left lung as DI had marked alveolar septal and bronchovascular abnormalities (p = .05 and p < .05 vs. sham) that were less prevalent in EI. EI also increased left lung volumes and alveolar counts compared to DI. EI and DI equally restored LPA pulsatility, R heart pressures, and distal LPA growth. EI and DI improved, but did not normalize LPA stenosis diameter (LPA/DAo ratio: Sham 1.27 ± 0.11 mm/mm, DI 0.88 ± 0.10 mm/mm, EI 1.01 ± 0.09 mm/mm) and pulmonary blood flow distributions (LPA-flow%: Sham 52 ± 5%, LPAS 7 ± 2%, DI 44 ± 3%, EI 40 ± 2%).

CONCLUSION

In this surgically created PAS model, EI was associated with improved lung parenchymal development compared to DI. Longer durations of L lung hypoperfusion did not detrimentally affect PA growth and R heart hemodynamics. Functional and anatomical discrepancies persist despite successful stent interventions that warrant additional investigation.

Susceptibility-based MR Imaging of Nitinol Stent

Conventional MR techniques have difficulty to accurately localize the stent position and access the stent restenosis because of the effects of susceptibility and radiofrequency (RF) shielding artifacts caused by stent mesh. Previous studies have demonstrated that a susceptibility-based positive contrast MR method exhibits excellent efficacy for visualizing MR compatible metal devices by taking advantage of their high magnetic susceptibility. However, the method is not evaluated in the visualization of stents. Therefore, the purpose of this study is to prospectively assess whether the susceptibility-based positive contrast method can be used to visualize the nitinol stents, with the comparison of two typical MR positive contrast techniques, i.e., susceptibility gradient mapping using the original resolution (SUMO) and the gradient echo acquisition for super-paramagnetic particles with positive contrast (GRASP). The experiment results showed that the susceptibility-based method provided better visualization and more precise localization of the stent than SUMO and GRASP.

Lumped-Parameter Circuit Platform for Simulating Typical Cases of Pulmonary Hypertensions from Point of Hemodynamics

Pulmonary hypertension (PH) presents unusual hemodynamic states characterized by abnormal high blood pressure in pulmonary artery. The objective of this study is to simulate how the hemodynamics develops in typical PH cases without treatment. A lumped-parameter circuit platform of human circulation system is set up to simulate hemodynamic abnormalities of PH in different etiologies and pathogenesis. Four typical cases are considered, which are distal pulmonary artery stenosis, left ventricular diastolic dysfunction, ventricular septal defect, and mitral stenosis. The authors propose regulation laws for chambers and vessels to adapt the abnormal hemodynamic conditions for each PH case. The occurrence and development of each PH case are simulated over time using the lumped-parameter circuit platform. The blood pressure, blood flow, pressure-volume relations for chambers and vessels are numerically calculated for each case of PH progression. The model results could be a quite helpful to understand the hemodynamic mechanism of typical PHs. Graphical Abstract.

Stent angioplasty of narrowed right ventricular outflow conduits and pulmonary arteries consistently reduces right ventricular systolic pressures and delays subsequent surgeries

Objectives

Narrowed right ventricular (RV) outflow conduits and pulmonary arteries (PA) increase RV pressures and warrant interventions. Stent angioplasty is an alternative to more morbid redo-surgery in developing countries. We evaluate the efficacy and safety of stenting and assess need for redo-surgical reinterventions on midterm follow-up after stent angioplasty.

Methods

Patients who underwent conduit, main PA and bilateral branch PA stenting for elevated RV pressures were analyzed retrospectively. Success was defined as 20% reduction in RV pressures or RV-aortic pressure ratio; 50% reduction in gradients or 50% increase of luminal diameter. Procedural results, complications and need for redo surgeries on follow-up were assessed.

Results

Among 60 patients aged 1–46 years, 57 were post-operative patients, who needed stenting at a median period of 48 months after surgery. Stenting succeeded in 98% and reduced RV pressures from 105.42 ± 28.39 mmHg to 54.46 ± 16.89 mmHg. Direct major procedural complications in five (8%) patients included procedural failure in one, stent migration in three and lung hemorrhage in one. None of the stented conduits needed a surgical change on a follow-up ranging 3–120 months. Following bilateral PA stenting in twenty-four patients, only two needed a repeat open-heart surgery during follow-up ranging 3–108 months. Catheter reinterventions on follow-up included elective percutaneous pulmonary valve implantation in nine patients and stent redilation in seven patients.

Conclusions

Stent angioplasty was safe and effective. Surgery was postponed in all stenosed conduits. Elective redilation of stents after bilateral PA stenting may be needed for somatic growth; but open-heart repeat surgeries can be avoided in a majority.

Consequences of an early catheter-based intervention on pulmonary artery growth and right ventricular myocardial function in a pig model of pulmonary artery stenosis

OBJECTIVE

To determine the consequences of an early catheter-based intervention on pulmonary artery (PA) growth and right ventricular (RV) myocardial function in an animal model of branch PA stenosis.

BACKGROUND

Acute results and safety profiles of deliberate stent fracture within the pulmonary vasculature have been demonstrated. The long-term impact of early stent intervention and deliberate stent fracture on PA growth and myocardial function is not understood.

METHODS

Implantation of small diameter stents was performed in a pig model of left PA stenosis at 6 weeks (10 kg) followed by dilations at 10 (35 kg) and 18 weeks (65 kg) with intent to fracture and implant large diameter stents. Hemodynamics, RV contractility, and 2D/3D angiography were performed with each intervention. The heart and pulmonary vasculature were histologically assessed.

RESULTS

Stent fracture occurred in 9/12 and implantation of large diameter stents was successful in 10/12 animals with no PA aneurysms or dissections. The final stented PA segment and distal left PA branch origins equaled the corresponding PA diameters of sham controls. Growth of left PA immediately beyond the stent was limited and there was diffuse fibro-intimal proliferation within the distal left and right PA. RV contractility was diminished in the intervention group and the response to dobutamine occurred uniquely via increases in heart rate.

CONCLUSIONS

Early stent intervention in this surgically created PA stenosis model was associated with improved growth of the distal PA vasculature but additional investigation of PA vessel physiology and impact on the developing heart are needed.

Interventional therapy in sarcoidosis-associated pulmonary arterial stenosis and pulmonary hypertension

BACKGROUNDS

Pulmonary sarcoidosis is often complicated by pulmonary hypertension, a complication that is associated with increased disability and mortality. To this point, however, little progress has been made in the treatment of sarcoidosis associated with pulmonary hypertension (SAPH).

METHODS

A prospective study was performed on 72 consecutive Chinese sarcoidosis patients followed at an outpatient clinic. The patients were evaluated by Doppler echocardiography and computed tomography pulmonary angiography. SAPH was confirmed by right heart catheterisation. The clinical parameters were compared before and 2 months after treatment with oral glucocorticoids. Eight stage III and IV patients with moderate to severe proximal pulmonary arterial stenosis (PAS) and SAPH underwent interventional therapy (IT) after prednisone treatment and were followed up at 3-month intervals.

RESULTS

After 2 months of prednisone treatment, 32 stage III and IV patients continued to display varying degrees of PAS and SAPH. Eight patients underwent IT without severe complications and made improvements in pulmonary arterial pressure, pulmonary vascular resistance, arterial oxygen saturation and WHO functional classification, with the improvements lasting more than 3 months.

CONCLUSIONS

PAS caused by external compression in sarcoidosis is a significant reason for SAPH. IT is effective and safe in the treatment of PAS and SAPH.

Cardiac catheterization in the early post-operative period after congenital cardiac surgery

OBJECTIVES

This study sought to demonstrate that early cardiac catheterization, whether used solely as a diagnostic modality or for the use of transcatheter interventional techniques, can be used effectively and with an acceptable risk in the post-operative period.

BACKGROUND

Cardiac catheterization offers important treatment for patients with congenital heart disease. Early post-operative cardiac catheterization is often necessary to diagnose and treat residual anatomic defects. Experience with interventional catheterization to address post-operative concerns is limited.

METHODS

This was a retrospective cohort study. The medical and catheterization data of pediatric patients who underwent a cardiac catheterization ≤30 days after congenital heart surgery between November 2004 and July 2013 were reviewed. Patients who underwent right heart catheterization and endomyocardial biopsy after heart transplantation were excluded.

RESULTS

A total of 219 catheterizations (91 interventional procedures, 128 noninterventional catheterizations) were performed on 193 patients. Sixty-five interventions (71.43%) were dilations, either balloon angioplasty or stent implantation. There was no difference in survival to hospital discharge between those who underwent an interventional versus noninterventional catheterization (p = 0.93). One-year post-operative survival was comparable between those who underwent an intervention (66%) versus diagnostic (71%) catheterization (p = 0.58). There was no difference in the incidence of major or minor complications between the interventional and diagnostic catheterization cohorts (p = 0.21).

CONCLUSIONS

Cardiac catheterization, including transcatheter interventions, can be performed safely in the immediate post-operative period after congenital heart surgery.

Balloon angioplasty and stent implantation performed through systemic-to-pulmonary artery shunts in infants and neonates

Branch pulmonary artery stenosis (BPAS) in the setting of systemic-pulmonary artery shunts (SPS) may result in significant sequelae. Limited information exists regarding the safety and efficacy of pulmonary artery balloon angioplasty and stent implantation via SPS in neonates and infants. This study aimed to examine the feasibility, safety, and efficacy of balloon angioplasty/stent implantation for BPAS performed via SPS in neonates and infants. A single-center retrospective analysis of all patients weighing 10 kg or less who underwent angioplasty for BPAS via SPS was performed. Systemic oxygen saturations and vessel diameter before, during, and after the procedure were compared. Between July 1996 and February 2008, 15 patients underwent 20 catheterizations for the treatment of 27 BPAS via SPS. The patients had a mean weight of 5.6 kg (range, 2.6-10 kg) and a mean age of 7.6 months (range, 7 days to 33 months). The SPS diameter ranged between 2 and 5 mm (median, 3.5 mm). Angioplasty was performed for all 27 lesions, and an additional stent was placed in 5 of these. The average lesion diameter increased from 2.3 ± 1.5 to 4.7 ± 1.7 mm (p < 0.05), and 25 (93 %) of the 27 lesions met the predetermined criteria for success. Systemic oxygen saturation increased from 73 ± 9.5 % to 82 ± 6.8 % immediately after intervention and was 83 ± 7.9 % at discharge (p < 0.05). There were no instances of shunt thrombosis. Two patients experienced transient hypotension during the procedure. No procedural deaths occurred. The study findings suggest that balloon angioplasty or stent implantation performed via SPS appears to be safe and effective treatment for BPAS in neonates and infants.

Medium and long-term outcomes after bilateral pulmonary artery stenting in children and adults with congenital heart disease

Percutaneous stenting of branch pulmonary arteries (PAs) has become an important interventional therapy in the complete management of congenital heart disease. Few data exist on long-term outcomes for patients requiring placement of bilateral stents. This study aimed to determine the medium- to long-term outcomes after bilateral stenting of branch PAs in patients with congenital heart disease. A retrospective study analyzed all procedural and follow-up data on patients undergoing bilateral PA stenting during a single procedure. From October 2001 to May 2012, 26 patients underwent bilateral PA stenting (total of 62 stents). The mean age of these patients was 9.5 ± 12 years, and their mean weight was 27 ± 19 kg. The mean procedural time was 191 ± 67 min, and the mean fluoroscopy time was 50 ± 29 min. The mean gradient across the right pulmonary artery decreased from 35 ± 22 to 11 ± 12 mmHg (p < 0.001). The left pulmonary artery gradient decreased from 32 ± 17 to 10 ± 12 mmHg (p < 0.001), and the right ventricle to descending aorta pressure ratio decreased from 71 ± 18 % to 46 ± 13 % (p < 0.001). Intraprocedural adverse events were encountered in four patients (1 small PA dissection, 2 intraprocedural arrhythmias, and 1 first-degree burn on the thigh). The mean follow-up period was 41 ± 23 months. Two deaths occurred. Further interventions were required for 12 patients. Bilateral PA stenting is effective and safe, with an instantaneous significant decrease in pressure gradients. The need for reintervention is common, so continued follow-up assessment is warranted.

Peripheral pulmonary artery stenosis masquerading as pulmonary hypertension: a diagnostic and therapeutic challenge

Isolated peripheral pulmonary artery stenosis presenting in adulthood is an uncommon cause of right ventricular hypertension and may be misdiagnosed as primary or thromboembolic pulmonary hypertension. Treatment consists of balloon angioplasty and stenting of the affected vessels, although the procedure can be complicated by reperfusion pulmonary edema.

Transcatheter rehabilitation of pulmonary arteries

Pulmonary arterial stenoses commonly occur in patients with congenital heart disease. Indications for treatment are based around reduction of right ventricular hypertension and equalization of flow to each lung and its constituent segments. There are many treatment approaches for these lesions depending on the anatomy, location and the age of the patient. Although surgical reconstruction remains an option, it is technically challenging and in many cases, the results are disappointing. In the modern era, the majority of these patients are treated with transcatheter therapy, including balloon angioplasty, and increasingly, the use of intravascular stents. In this article, we discuss these issues and deal with both the technical approach to transcatheter therapy and up-to-date results.

Difficult to control asthma in the patient with pseudoachondroplasia

Pseudoachondroplasia (PsA) is a type of short-limbed dwarfism resulting from mutations in the cartilage oligomeric matrix protein gene. Skeletal involvement in the PsA is well-described but there are not any published cases reporting airways involvement. The authors present a case of a female with the PsA and congenital anomalies of the respiratory tract resulting in the tracheobronchomalacia and a difficult to control asthma.

MRI may be sufficient for noninvasive assessment of great vessel stents: an in vitro comparison of MRI, CT, and conventional angiography

OBJECTIVE

The purpose of this study was to compare the diagnostic performance of MRI and CT assessment of great vessel stents in an in vitro model.

MATERIALS AND METHODS

Three contemporary great vessel stent materials (nitinol, platinum-iridium, and stainless steel) were assessed with three luminal conditions: no stenosis, internal stenosis, and external stenosis. Stents of the same material were implanted into an aorta model that was attached to an animal bypass pump with pulsatile flow. Each stent was imaged with conventional angiography as reference standard, 10 different MRI sequences, and CT. The sensitivity and specificity for the identification of stent stenosis was determined and stent lumen measurements compared.

RESULTS

Of the investigated MRI sequences, three had the highest overall sensitivity and specificity for the identification of stent stenosis in all studied materials: through-plane gradientrecalled echo (GRE) with 75° flip angle (100% and 95%, respectively), in- and through-plane steady-state free precession (SSFP) (99% and 90%) and MR angiography (MRA) with 75° flip angle (93% and 85%). Comparable sensitivity and specificity were achieved with CT (98% and 93%). GRE, SSFP, and MRA sequences tended to underestimate stent lumen diameter in externally nonstenosed stents and overestimate diameter in internally stenosed stents (p < 0.05). CT slightly underestimated external stenoses in all stent types (p < 0.05).

CONCLUSION

Defined MRI sequences are feasible to assess nitinol, platinum-iridium, and stainless steel great vessel stents with diagnostic performance comparable with CT.