Balloon angioplasty for obstructed modified systemic-pulmonary artery shunts and pulmonary artery stenoses

Catheter Intervention for Flow Regulatory Clips on Palliative Shunts and Conduits in Patients with Congenital Heart Disease

Catheter intervention (CI) for a Blalock-Taussig shunt (BTS) or a ventricle-to-pulmonary artery conduit (VPC) is often required after a palliative surgery for congenital heart disease. Flow regulatory clips help improve interstage mortality; their use necessitates CIs to prevent cyanosis. To study the CI outcomes in patients who underwent palliative surgery with either BTSs or VPCs with flow regulatory clips. This single-center retrospective study evaluated demographic characteristics and interventional outcomes of 49 consecutive pediatric patients who required CI for BTS (BTS group) or VPC (VPC group) between January 2008 and September 2018. Overall, 34 and 18 procedures were performed in the BTS and VPC groups, respectively. Moreover, 19/32 (59.3%) and 12/17 (70.1%) patients from the BTS and VPC groups had flow regulatory clips, respectively. All clips were unclipped successfully; one patient in each group underwent staged unclipping. A higher proportion of "clipped patients" underwent CI due to desaturation [clipped vs. non-clipped: BTS, 10/20 (50.0%) vs. 3/14 (21.4%), p = 0.092; VPC, 9/13 (69.2%) vs. 1/5 (20.0%), p = 0.060]. Most clipped patients successfully progressed to the next stage [BTS, 19/20 (95.0%); VPC, 12/13 (92.3%)]. Severe adverse events (SAEs) were more frequent in the VPC group than in the BTS group [3/13 (23.1%) vs. 0/20 (0%), p = 0.024]. Two patients developed an atrioventricular block (requiring an atropine infusion), while one died due to pulmonary overcirculation. While the indication of CI was cyanosis for a higher proportion of clipped patients, all clips were unclipped successfully. The incidence of CI-related SAEs was higher in the VPC group than in the BTS group.

Percutaneous stent implantation for occluded central shunts in adults: A case report and review of current evidence

Background

Patients with cyanotic complex congenital heart defects (CHDs) commonly undergo palliation with interposition of systemic-to-pulmonary shunts (SPSs). These palliative shunts are rarely found in adults with CHDs and can be complicated with progressive obstruction or total occlusion during follow-up. The best treatment option for shunt re-permeabilization is challenging and case-oriented because most patients are high risk candidates for redo surgeries. We aimed to review the current evidence on percutaneous stent implantation to treat failed SPSs.

Methods

We performed a comprehensive literature review on percutaneous stent implantation to treat failed and occluded SPSs. We also reported the case of a 33-year-old man with cyanotic CHD and a occluded central aorto-pulmonary shunt, who was successfully treated with percutaneous balloon dilatation and subsequently stent implantation at our institution.

Result

We identified and included 31 articles reporting on 150 patients and 165 stent implantations in failed SPSs. The age of patients at the time of stent implantation ranged from 6 days to 47 years. The time between the surgical shunt creation and transcatheter intervention ranged from 1 day to 17 years. Overall, 161/165 (97.5%) stent implantations were successful. The most common clinical presentation was cyanosis and decreased atrial oxygen saturations and the indication for stent implantation was shunt obstruction and stenosis.

Conclusion

This review highlights the benefits of endovascular stenting to permeabilize failed SPSs in children and adults with complex CHD who are classified as poor candidates for re-surgical repair.

Use of the novel curved GOKU balloon catheter for acute-angled lesions in palliative surgery for congenital heart disease: comparison with a conventional straight balloon

Obstruction develops commonly at the acute-angled portion of the vessels following palliative surgery, such as systemic-pulmonary shunt (SP shunt), right ventricle-to-pulmonary artery shunt (RV-PA shunt) in the Norwood-Sano procedure for hypoplastic left heart syndrome, and cavopulmonary (Glenn) anastomosis. Although balloon angioplasty is a treatment option, dilation with existing straight balloons is sometimes ineffective and technically complicated because of balloon slippage and target vessel distortion. In this study, we investigated the effectiveness of a curved GOKU balloon catheter for balloon angioplasty in postoperative acute-angled lesions associated with palliative surgery for congenital heart disease. We reviewed patients who underwent balloon angioplasty for angled lesions complicated by SP shunt, RV-PA shunt, or Glenn anastomosis, using the novel curved GOKU or a conventional balloon catheter, such as a Sterling balloon catheter. We evaluated patients' backgrounds, balloon specifications, target lesion anatomical features and angles, and short-term outcomes. We evaluated 45 procedures in 18 patients. A curved GOKU was used in 20 procedures, and a Sterling balloon in 25 procedures. The angulation of the lesions at maximum balloon inflation was significantly smaller using a curved GOKU vs a Sterling balloon [70-120 (mean ± standard deviation, 97 ± 40) degrees vs 110-180 (149 ± 46) degrees, respectively; p < 0.001], while the original angle was similar between the groups. Patients' short-term outcomes with the curved GOKU were excellent, with a significantly better percent increase in minimum lumen diameter of 0-220% (92% ± 66%) vs 0-46% (18% ± 15%) with the Sterling balloon (p < 00.1) and with less frequent balloon slippage. The curved GOKU was more effective in balloon angioplasty for acute-angled lesions compared with a conventional straight balloon, likely because of better conformability to the lesion angle and slip resistance.

Successful coil embolisation for an arterio-bronchial fistula in a child presenting catastrophic haemoptysis

We report the case of a 2-year-old girl who developed catastrophic haemoptysis due to an arterio-bronchial fistula after transcatheter balloon dilatation for a narrowing aortopulmonary shunt. We embolised the fistula while haemoptysis was controlled with the left bronchial block ventilation and haemostatic balloon occlusion of the left subclavian artery. An arterio-bronchial fistula is an extremely rare complication for balloon dilatation of an aortopulmonary shunt.

Off-Label use of Stretchable Polytetrafluoroethylene: Overexpansion of Synthetic Shunts

Purpose

To describe our experience with balloon dilatation and stenting of modified systemic-to-pulmonary artery (PA) shunts in relation to an assessment and interpretation of the mechanical properties of thin-walled expandable polytetrafluoroethylene (ePTFE) stretch vascular grafts.

Methods

Our pediatric cardiology/cardiac surgery database was reviewed to identify all infants and children with a modified systemic-to-PA shunt who underwent cardiac catheterization. Reports and images were reviewed. Thin-walled stretchable and regular Gore-Tex® vascular grafts were mechanically compared using tensiometry.

Results

11 patients underwent dilatation or stenting procedures of a systemic-to-PA shunt. No major complications occurred and none of our patients died during or due to this intervention. High pressures in balloons and stents with diameters larger than the graft were used. Shunt diameters and oxygen saturation levels increased from 2.05 ± 1.25 mm to 4.75 ± 0.88 mm and with 12 ± 6.8%, respectively. In 6 patients re-catheterizations were performed. Four patients died, all with patent shunts. The fail-stress and the fail-strain in the circumferential direction of the stretchable graft were significantly higher than in the non-stretchable graft.

Conclusions

Dilatation and stenting of stenosed modified systemic-to-PA shunts is feasible and safe. Dilatation and stenting of these shunts to calibers larger than those provided by the manufacturer is possible. Results of our technical study posit a great advantage for the use of the thin-walled stretch configuration of ePTFE.

Catheter-based interventions for modified Blalock-Taussig shunt obstruction: a 20-year experience

Thrombotic occlusion of a modified Blalock-Taussig (BT) shunt is rare, leading to life-threatening hypoxemia. Rescue percutaneous interventions may allow recanalization of the systemic-to-pulmonary shunt but data on large patients' scales are lacking. We aimed to describe safety and effectiveness of catheter-based interventions to restore modified BT shunt patency. All patients who attempted transcatheter intervention for thrombotic occlusion of a modified BT shunt at our Institution from 1994 to 2014 were reviewed. Characteristics, management, and outcomes of the 28 identified patients were analyzed. Thirty-three procedures were performed at a median age of 0.6 years old (range 0.03-32.1 years) and a median weight of 5.8 kg (range 2.2-82 kg). Percutaneous intervention consisted in 33 balloon angioplasty (100 %) and 14 stent implantations (42.4 %). Thrombolytic agents were also used in 6.1 % cases. No peri-procedural death occurred but complications were observed in five patients (15.2 %), including one catheter-induced transient complete atrioventricular block, one cardiac tamponade, and one massive thrombo-embolic stroke. Early procedural success was obtained in 28 patients (84.8 %) and remained long-lasting in 26 patients (78.8 %). A young age and a low body-weight at the time of the procedure were significantly associated with procedural failure (p = 0.0364 and p = 0.0247, respectively). Although technically challenging and carrying potential major complications, transcatheter intervention can be considered as an efficient rescue strategy to restore patency in case of thrombotic obstruction of a modified BT shunt.

Stenting for curved lesions using a novel curved balloon: Preliminary experimental study

BACKGROUND

Stenting may be a compelling approach to dilating curved lesions in congenital heart diseases. However, balloon-expandable stents, which are commonly used for congenital heart diseases, are usually deployed in a straight orientation. In this study, we evaluated the effect of stenting with a novel curved balloon considered to provide better conformability to the curved-angled lesion.

MATERIALS AND METHODS

In vitro experiments: A Palmaz Genesis(®) stent (Johnson & Johnson, Cordis Co, Bridgewater, NJ, USA) mounted on the Goku(®) curve (Tokai Medical Co. Nagoya, Japan) was dilated in vitro to observe directly the behavior of the stent and balloon assembly during expansion. Animal experiment: A short Express(®) Vascular SD (Boston Scientific Co, Marlborough, MA, USA) stent and a long Express(®) Vascular LD stent (Boston Scientific) mounted on the curved balloon were deployed in the curved vessel of a pig to observe the effect of stenting in vivo.

RESULTS

In vitro experiments: Although the stent was dilated in a curved fashion, stent and balloon assembly also rotated conjointly during expansion of its curved portion.

ANIMAL EXPERIMENT

In the primary stenting of the short stent, the stent was dilated with rotation of the curved portion. The excised stent conformed to the curved vessel. As the long stent could not be negotiated across the mid-portion with the balloon in expansion when it started curving, the mid-portion of the stent failed to expand fully. Furthermore, the balloon, which became entangled with the stent strut, could not be retrieved even after complete deflation.

CONCLUSION

This novel curved balloon catheter might be used for implantation of the short stent in a curved lesion; however, it should not be used for primary stenting of the long stent. Post-dilation to conform the stent to the angled vessel would be safer than primary stenting irrespective of stent length.

Novel curved balloon catheter for dilating postoperative angled lesions associated with congenital heart disease

OBJECTIVES

This study aimed to analyze the surface stress generated by a novel curved balloon and assess its efficacy for treating angular lesions associated with congenital heart disease.

BACKGROUND

Obstructions at the anastomosis of aortopulmonary shunts and cavopulmonary connections may occur postoperatively. Catheter interventions are often performed for such lesions; however, acute angulation may cause balloon slippage or inappropriate stress on the vessel wall.

METHODS

We dilated the curved balloon in a curved vessel model and measured the resultant wall stress and its distribution. Clinical evaluations were performed using this balloon in angled lesions.

RESULTS

In the curved vessel model, curved balloons generated uniform stress on the lesser and greater curvatures (curved type, lesser/greater = 0.343 MPa/0.327 MPa; P = 0.61), whereas straight balloons caused disproportionate stress (straight type, lesser/greater = 0.358 MPa/0.254 MPa; P = 0.19). However, the difference in average stress was not statistically significant. Furthermore, the stress was uniform along the entire length of the curved balloon, but differed between the mid and end portions of the straight balloon. Curved balloon dilations were performed for 10 lesions in 7 patients. The curved balloon conformed well to the angulated lesion without slipping. The median percent change in the minimal lumen diameter (MLD) was 64% (range, 0-206%). In 5 lesions, MLD increased by ≥50%. Oxygen saturation increased by 5% (0-9%).

CONCLUSIONS

Although further clinical evaluation is necessary, this novel curved balloon may be a reasonable alternative in angled lesions, providing better conformability and preventing excessive stress to the vessel wall adjacent to the stenosis.

Complete Blalock-Taussig shunt obstruction in < 24 hours post-operative period in a neonate treated emergently using transcatheter angioplasty and low dose local recombinant TPA

A 12-day-old infant with pulmonary atresia, intact ventricular septum, and pulmonary blood flow through a ductus arteriosus developed complete shunt obstruction within 12 hr of creation of a modified Blalock-Taussig shunt. Low dose recombinant tissue plasminogen activator was administered locally as two 0.03 mg/kg bolus injections and was followed by balloon angioplasty. This resulted in complete recanalization of the shunt without any hemorrhagic complications.

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.

Superior cavopulmonary anastomosis timing and outcomes in infants with single ventricle

OBJECTIVES

We sought to identify factors associated with the timing and surgical outcomes of the superior cavopulmonary anastomosis.

METHODS

The Pediatric Heart Network's Infant Single Ventricle trial database identified participants who underwent superior cavopulmonary anastomosis. Factors potentially associated with age at superior cavopulmonary anastomosis, length of stay and death by 14 months of age were evaluated. Factors included subject demographics, cardiac anatomy, measures from neonatal hospitalization and pre-superior cavopulmonary anastomosis visit, adverse events, echocardiographic variables, intraoperative variables, superior cavopulmonary anastomosis type, and number of concurrent cardiac surgical procedures. Age at superior cavopulmonary anastomosis was analyzed using Cox proportional hazards regression. Natural log length of stay was analyzed by multiple linear regression.

RESULTS

Superior cavopulmonary anastomosis was performed in 193 subjects at 5.2 months of age (interquartile range, 4.2, 6.2) and weight of 5.9 kg (interquartile range, 5.3, 6.6). The median length of stay was 7 days (interquartile range, 6, 10). There were 3 deaths and 1 transplant during the superior cavopulmonary anastomosis hospitalization, and 3 deaths and 3 transplants between discharge and 14 months of age. Age at superior cavopulmonary anastomosis was associated with center and interstage adverse events. A longer length of stay was associated with younger age and greater case complexity. Superior cavopulmonary anastomosis type, valve regurgitation, ventricular ejection fraction, and ventricular end-diastolic pressure were not independently associated with age at superior cavopulmonary anastomosis or the length of stay.

CONCLUSIONS

Greater case complexity and more frequent interstage adverse events are associated with an earlier age at superior cavopulmonary anastomosis. Significant variation in age at superior cavopulmonary anastomosis among centers, independent of subject factors, highlights a lack of consensus regarding the optimal timing. Factors associated with length of stay could offer insights for improving presuperior cavopulmonary anastomosis care and surgical outcome.

Antithrombotic therapy in neonates and children: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

Neonates and children differ from adults in physiology, pharmacologic responses to drugs, epidemiology, and long-term consequences of thrombosis. This guideline addresses optimal strategies for the management of thrombosis in neonates and children.

METHODS

The methods of this guideline follow those described in the Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines.

RESULTS

We suggest that where possible, pediatric hematologists with experience in thromboembolism manage pediatric patients with thromboembolism (Grade 2C). When this is not possible, we suggest a combination of a neonatologist/pediatrician and adult hematologist supported by consultation with an experienced pediatric hematologist (Grade 2C). We suggest that therapeutic unfractionated heparin in children is titrated to achieve a target anti-Xa range of 0.35 to 0.7 units/mL or an activated partial thromboplastin time range that correlates to this anti-Xa range or to a protamine titration range of 0.2 to 0.4 units/mL (Grade 2C). For neonates and children receiving either daily or bid therapeutic low-molecular-weight heparin, we suggest that the drug be monitored to a target range of 0.5 to 1.0 units/mL in a sample taken 4 to 6 h after subcutaneous injection or, alternatively, 0.5 to 0.8 units/mL in a sample taken 2 to 6 h after subcutaneous injection (Grade 2C).

CONCLUSIONS

The evidence supporting most recommendations for antithrombotic therapy in neonates and children remains weak. Studies addressing appropriate drug target ranges and monitoring requirements are urgently required in addition to site- and clinical situation-specific thrombosis management strategies.

Hypoplastic left heart syndrome: current considerations and expectations

In the recent era, no congenital heart defect has undergone a more dramatic change in diagnostic approach, management, and outcomes than hypoplastic left heart syndrome (HLHS). During this time, survival to the age of 5 years (including Fontan) has ranged from 50% to 69%, but current expectations are that 70% of newborns born today with HLHS may reach adulthood. Although the 3-stage treatment approach to HLHS is now well founded, there is significant variation among centers. In this white paper, we present the current state of the art in our understanding and treatment of HLHS during the stages of care: 1) pre-Stage I: fetal and neonatal assessment and management; 2) Stage I: perioperative care, interstage monitoring, and management strategies; 3) Stage II: surgeries; 4) Stage III: Fontan surgery; and 5) long-term follow-up. Issues surrounding the genetics of HLHS, developmental outcomes, and quality of life are addressed in addition to the many other considerations for caring for this group of complex patients.

An institutional approach to interventional strategies for complete vascular occlusions

Complete vascular occlusions are rare but potentially lethal. Reports on transcatheter therapy are limited to solitary case reports. The study was conducted as a single-center retrospective chart review. Between January 2003 and December 2009, 26 patients underwent cardiac catheterizations for either a known complete thoracic vascular occlusion or for incidental complete vascular occlusion that was noted during cardiac catheterization. Procedural technique, risk factors, and outcomes are reviewed. Median age at the time of diagnosis was 13.3 years (range 2 months to 54 years). In 6 of 26 (23%) patients, the vascular occlusion was of acute onset. Ninety-two percent of patients had at least 1 known risk factor for vascular occlusion, whereas 54% of patients had ≥ 2 risk factors. Successful rehabilitation was achieved in 19 patients, with direct catheter and/or wire manipulation being used to cross the occluded vessel in 15 (75%) patients, radiofrequency (RF) perforation in 3 patients, and perforation with Brockenbrough needle in 1 patient. Subsequent techniques included AngioJet (n = 2), balloon angioplasty and/or stent implantation (n = 18), and adjuvant local administration of recombinant tissue-plasminogen activator (n = 3). Reinterventions were required in 5 patients, and 8 patients died during the study period from causes unrelated to the catheterization procedure(s). Median follow-up of patients after successful recanalization was 12.6 months (range 1 day to 64 months), and the median duration of survival free from reintervention was 11.8 months (range 1 day to 64 months). In most patients, risk factors can be identified that are associated with the occurrence of a complete vascular occlusion. Different treatment strategies are used in patients having chronic compared with acute occlusions. Residual vascular lesions (hypoplasia or stenosis) are often associated with occurrence of reobstructions and should therefore be treated to prevent such an occurrence. Postprocedural anticoagulation is important in maintaining vascular patency.

Stent expansion of stretch Gore-Tex grafts in children with congenital heart lesions

OBJECTIVE

To evaluate the efficacy and safety of expanding vascular shunt grafts beyond original nominal diameter using stents.

METHODS

Bench testing confirmed the expandability of 3.5 mm and 4.0 mm vascular Gore-Tex stretch grafts. A retrospective analysis included eleven systemic to pulmonary artery shunts with diminished flow which were stented with the aim of increasing the original nominal diameter of the shunts.

RESULTS

During bench testing, the grafts could be expanded to 4.5 mm and 5.8 mm, respectively. Fourteen stents were implanted in 11 stretch grafts a median of 18.9 months (3.2; 21.6 months) after shunt surgery. There was a median increase in diameter of 1.4 mm (0.9; 1.7 mm) [P = 0.001, 95% CI: 0.47; 1.7) from original nominal to final stented diameter of the shunts with a median gain of 28%. A simultaneous improvement in saturations from a median of 73% (66; 77%) to 87% (84; 89%) [P = 0.015; 95% CI: 3; 22] was observed. No complications were experienced during the procedures.

CONCLUSION

In our limited experience, stretch Gore-Tex vascular grafts can be safely expanded beyond nominal diameters using high pressure vascular stents. This leads to improvement in saturation and pulmonary blood flow. It allows the clinician to tailor pulmonary flow in relation to pulmonary artery size and growth, ensuring best possible timing for the next surgical procedure.

Acute and late obstruction of a modified Blalock-Taussig shunt: a two-center experience in different catheter-based methods of treatment

Modified Blalock-Taussig (B-T) shunt occlusion results in a sudden reduction of pulmonary vascular perfusion, causing dramatic saturation drop and cyanosis which pose a direct hazard to a child's life. The results of percutaneous local r-tpa infusion, balloon angioplasty and additionally stent implantation in obstructed modified B-T shunts were studied to assess their role as an alternative to a re-do surgery. We outline two pediatric centers' experience (period 2004-2008) regarding the effectiveness of various emergency treatment methods for occlusion or critical stenosis of systemic-to-pulmonary arterial shunts in 23 children. Local r-tpa infusion via catheter was performed in 12/23 patients, balloon angioplasty in 22/23 and additionally stent implantation in 3/23 children. Procedures were successful in 22/23 patients (96%), with an increase in arterial saturation [average: 30%; standard deviation (S.D.) 15%; Shapiro-Wilk test; dependent t-test-P<0.01]. Unrestricted contrast flow was achieved in 18 patients, reduced central flow in three and minimal flow in one child. Neither local nor systemic complications occurred. Our experience demonstrates the possibility of successful early shunt recanalization with the use of local thrombolytic therapy combined with the balloon angioplasty. The presence of old fixed thrombus with neointimal hypertrophy in the shunt constitutes an indication for endovascular stent implantation.