Dilatation mechanism of balloon angioplasty in children: assessment by angiography and intravascular ultrasound

Renovascular hypertension in children

Paediatric hypertension, defined as systolic blood pressure > 95th percentile for age, sex and height is often incidentally diagnosed. Renovascular hypertension (RVH) is responsible for 5-25% of hypertension in children. Renal artery stenosis and middle aortic syndrome can both can be associated with various conditions such as fibromuscular dysplasia, Williams syndrome & Neurofibromatosis type 1. This paper discusses the approaches to diagnosis and interventional management and outcomes of renovascular hypertension in children. Angiography is considered the gold standard in establishing the diagnosis of renovascular disease in children. Angioplasty is beneficial in the majority of patients and generally repeated angioplasty is considered more appropriate than stenting. Surgical options should first be considered before placing a stent unless there is an emergent requirement. Given the established safety and success of endovascular intervention, at most institutions it remains the preferred treatment option.

Balloon Angioplasty as a Modality to Treat Children with Pulmonary Stenosis Secondary to Complex Congenital Heart Diseases

BACKGROUND

Pulmonary stenosis is common in children with complex congenital heart diseases. Proper management of this problem, especially postoperatively, is still controversial. This study was designed to assess the rate and determinants of success or failure of balloon angioplasty for such lesions.

METHODS

Clinical and hemodynamic data from 40 pediatric patients (24 boys and 16 girls) with complex congenital heart diseases who underwent balloon angioplasty were reviewed retrospectively from January 2012 to December 2016. Patients were divided into four groups according to the site of stenosis, which included pulmonary valve stenosis (PVS), valved conduit stenosis, pulmonary artery stenosis (PAS), and supravalvular pulmonary stenosis (SVPS). Success rates were calculated according to defined criteria for initial success and favorable clinical impacts, and comparison between the successful subgroup and the unsuccessful subgroups was analyzed.

RESULTS

Grouped by the site of stenosis, initial success rates varied from 40.0% to 52.4% with the greatest success being seen in the PVS group, followed by the PAS group and SVPS group. In the PVS group and the PAS group, there was no statistical difference among age at dilation, postoperative interval, balloon/stenosis ratio, or pressure gradient predilation between the successful and the unsuccessful subgroups. Favorable clinical impacts included success rates of balloon angioplasty in the SVPS group, which was best (100%), followed by the PVS group (90.9%) and the PAS group (85.7%). There were a total of two transient complications (5.0%).

CONCLUSIONS

Balloon angioplasty was proven to be a safe and useful modality in children with complex congenital heart diseases and postoperative pulmonary stenosis, which should be the initial therapeutic modality in selected patients.

Remedial operations for failed endovascular therapy of 32 renal artery stenoses in 24 children

BACKGROUND

Percutaneous transluminal angioplasty (PTA) for the treatment of pediatric renovascular hypertension (RVH) in contemporary practice is accompanied with ill-defined complications. This study examines the mode of pediatric renal PTA failures and the results of their surgical management.

METHODS

Twenty-four children underwent remedial operations at the University of Michigan from 1996 to 2014 for failures of renal PTA. Their clinical courses were retrospectively reviewed and results analyzed.

RESULTS

Renal PTA of 32 arteries, including 13 with stenting, was performed for severe RVH in 12 boys and 12 girls, having a mean age of 9.3 years. Developmental ostial stenoses affected 22 children. PTA failures included: 27 restenoses and five thromboses. Remedial operations included: 13 renal artery-aortic reimplantations, one segmental renal artery-main renal artery reimplantation, ten aortorenal bypasses, one arterioplasty, one iliorenal bypass, and six nephrectomies for unreconstructable arteries; the latter all in children younger than 10 years. Follow-up averaged 2.1 years. Postoperatively, hypertension was cured, improved, or unchanged in 25, 54, and 21 %, respectively. There was no perioperative renal failure or mortality.

CONCLUSIONS

Renal PTA for the treatment of pediatric RVH due to ostial disease may be complicated by failures requiring complex remedial operations or nephrectomy, the latter usually affecting younger children.

Coarctation of the aorta: Management from infancy to adulthood

Coarctation of the aorta is a relatively common form of congenital heart disease, with an estimated incidence of approximately 3 cases per 10000 births. Coarctation is a heterogeneous lesion which may present across all age ranges, with varying clinical symptoms, in isolation, or in association with other cardiac defects. The first surgical repair of aortic coarctation was described in 1944, and since that time, several other surgical techniques have been developed and modified. Additionally, transcatheter balloon angioplasty and endovascular stent placement offer less invasive approaches for the treatment of coarctation of the aorta for some patients. While overall morbidity and mortality rates are low for patients undergoing intervention for coarctation, both surgical and transcatheter interventions are not free from adverse outcomes. Therefore, patients must be followed closely over their lifetime for complications such as recoarctation, aortic aneurysm, persistent hypertension, and changes in any associated cardiac defects. Considerable effort has been expended investigating the utility and outcomes of various treatment approaches for aortic coarctation, which are heavily influenced by a patient’s anatomy, size, age, and clinical course. Here we review indications for intervention, describe and compare surgical and transcatheter techniques for management of coarctation, and explore the associated outcomes in both children and adults.

Usefulness of balloon angioplasty for the right ventricle-pulmonary artery shunt with the modified Norwood procedure

OBJECTIVE

We sought to evaluate the efficacy of balloon angioplasty (BA) for severely desaturated patients due to a stenotic right ventricle (RV) to pulmonary artery (PA) shunt following modified Norwood procedure.

METHODS

Of 87 patients who underwent a Norwood procedure with the RV-PA shunt between February 1998 through March 2010, 22 (25%) patients underwent BA. The efficacy of BA was assessed by angiographic measurement of the changes in the internal diameters of the stenotic portions of the shunt, changes in arterial saturation and clinical outcomes.

RESULTS

BA was performed for stenotic RV-PA shunts following stage I palliation (n = 17, 77%), or those placed as an additional blood source (n = 5, 23%, 3 patients awaiting biventricular repair, 2 patients following stage II palliation). The location of the BA was at the distal anastomosis in 12 (54.5%), proximal anastomosis in 21 (95.4%) and in the mid-portion of the shunt in 11 (50%) cases. The diameters of these three shunt portions were measured from the anterior-posterior and lateral angiographic images, increasing significantly after BA (p < 0.0001) in all. Arterial saturation significantly improved after BA in all cases (66.5 ± 4.3% to 79.4 ± 3.4%, p < 0.0001). Freedom from reintervention was 100%. All patients underwent subsequent elective planned surgery at an appropriate age with no mortality.

CONCLUSIONS

A BA-alone strategy for a stenotic RV-PA shunt was effective for all three shunt portions, minimizing shunt-related premature surgical intervention.

Percutaneous interventions of the aorta

Coarctation of the aorta includes a wide array of anatomical and pathophysiological variations that may cause important long-term morbidity and mortality. Percutaneous techniques, such as balloon dilation and stenting, allow clinicians to safely decrease or abolish most gradients along the aorta, albeit with limitations. Proper patient selection and interventional technique allow clinicians to obtain an adequate stretch or therapeutic tear of the vessel wall, but should avoid complications, such as an excessive tear, dissection, aneurysm formation or rupture. The interventional technique is tailored by patient characteristics such as age, size and growth potential, by characteristics of the lesion such as degree of narrowing, length, angulation(s) and by local regulations.

Effectiveness and safety of balloon dilation of native aortic coarctation in premature neonates weighing < or = 2,500 grams

Six neonates weighing < or = 2,500 g with native coarctation of the aorta underwent balloon dilation. Of the 6 neonates, 4 were female and 2 were male, with a mean age of 14 days (range 9 to 20) and a mean weight of 1,900 g (range 790 to 2,500). The procedure was acutely successful in all 6 patients; the peak gradient decreased from 38 + or - 19 mm Hg to 11 + or - 3 mm Hg. The diameter increased from 1.5 + or - 0.6 mm to 3.6 + or - 0.7 mm. Of the 6 patients, 3 had required no additional intervention at a mean of 42 months after the initial dilation, and 3 had developed restenosis a mean of 2.4 months after the initial dilation and underwent successful redilation. Of the latter 3 patients, 2 developed restenosis and underwent surgical repair 37 and 68 days after the second dilation, and 1 of these patients developed recoarctation after surgery that was treated successfully with balloon dilation 54 days after the end-to-end repair. In conclusion, premature neonates weighing < or = 2,500 g with coarctation of the aorta appear to respond acutely to balloon dilation. Some patients will have a successful long-term result after a single balloon dilation procedure. However, restenosis is common and tends to develop rapidly.

[Catheter-based balloon dilatation of the frontal, maxillary, and sphenoid ostia: a new procedure in sinus surgery]

BACKGROUND

Endoscopic sinus surgery is the procedure of choice for treating chronic rhinosinusitis. This paper describes a new minimally invasive method to restore ostium patency without removing tissue: the balloon sinuplasty technique.

PATIENTS AND METHODS

Two patients were treated with the new procedure. One patient had her maxillary and sphenoid ostia dilated; the other patient had both frontal ostia, both maxillary ostia, and the right sphenoid ostia dilated.

RESULTS

The balloon dilatations of the ostia were achieved successfully without impairing the mucosal circumference. There was no bleeding, and nasal packing was not necessary. The postoperative healing process showed no complications.

CONCLUSION

This paper discusses the advantages and disadvantages as well as the indications and contraindications of this method. The balloon sinuplasty technique is an easily performed surgery; for selected indications, it seems especially suited for opening blocked ostia.

Self- and balloon-expandable stent implantation for severe native coarctation of aorta in adults

BACKGROUND

Balloon angioplasty for native coarctation of the aorta (CoA) in adults, though promising, is sometimes limited by significant residual gradient (>20 mm Hg). Few studies available have reported on use of balloon-expandable stents in such a situation. We evaluated the use of self- and balloon-expandable stents in patients with suboptimal response to balloon angioplasty (BA).

METHODS

Twenty-one hypertensive patients (age, 18 to 61 years; mean, 28.6 +/- 11.2 years) with native CoA and in whom results of BA were suboptimal (ie, residual peak systolic gradient [PSG] >20 mm Hg) underwent stent implantation. Balloon-expandable Palmaz stents were implanted in 5 patients (group A) and self-expandable nitinol aortic stents in the remaining 16 patients (group B).

RESULTS

In group A, PSG decreased from 62.8 +/- 10.6 (53 to 80) mm Hg to 28.1 +/- 6.3 (22 to 39) mm Hg after BA. Systolic gradient further decreased to 8.3 +/- 3.9 (2 to 16) mm Hg (P <.001) after implantation of the balloon-expandable Palmaz stent. In group B, PSG decreased from 70.2 +/- 24.6 (40 to 110) mm Hg to 28.4 +/- 9.8 (22 to 42) mm Hg after BA and further reduced to 9.0 +/- 5.5 (4 to 16) mm Hg (P <.001). One of these patients had a nitinol self-expandable stent implanted after a Palmaz stent embolized immediately after deployment. Nitinol stents were easier to deploy and conformed better to aortic anatomy compared with balloon-expandable stents. In group A, the diameter of the coarcted segment increased from 3.8 +/- 0.8 mm to 13.3 +/- 0.8 mm (P <.001) after stent implantation and in group B it increased from 4.5 +/- 1.1 mm to 14.1 +/- 2.1 mm (P <.001). There was no significant difference between the two groups in the PSG and diameter of the coarcted segment before and after stent implantation. With the exception of one case, in which a Palmaz stent embolized, there was no other complication in our series. On follow-up of 12 to 71 months (mean, 40.7 +/- 5.8 months) all the implanted stents remained in their original position and none showed evidence of fracture. Improvement in hypertension was seen in 20 of 21(95.2%) of the patients. On recatheterization and angiography 1.2 +/- 0.6 years after implantation in 19 patients, one patient showed an increase in PSG to 27 mm Hg across the nitinol stent and underwent successful redilation. No increase in gradient was seen in other patients. Beneficial late remodeling was seen in 10 of 14(71.4%) of patients restudied after implantation of self-expandable stent. None of the patients showed aneurysm formation.

CONCLUSIONS

Stent implantation is safe and effective in improving suboptimal results after BA for CoA. Self-expandable stents were easier to implant, adapted better to the wall of the aorta, and in most patients had similar efficacy in reducing coarctation as balloon-expandable stents.

Interventional catheterization management of perioperative peripheral pulmonary stenosis: balloon angioplasty or endovascular stenting

There is limited reported experience of catheterization therapy for peripheral pulmonary stenosis (PPS) at a surgical site in the early postoperative period. We reviewed the clinical course of patients undergoing interventional catheterization for PPS at a surgical site < 7 weeks after surgery. Successful dilation (SD) was defined as > 50% increase in predilation diameter. From 1984 to 2000, 17 patients had 19 proximal pulmonary arteries dilated 1 to 46 (median 8) days postoperatively. Median age and weight were 3.1 year and 12.7 kg. Three arteries were initially occluded. Seventeen arteries had initial BD with postintervention imaging available in 15; 8 arteries had SD. The arterial diameter increased from 3.9 +/- 2.6 to 5.5 +/- 2.8 mm (P < 0.001). Nine of these arteries had stents placed with diameter increasing to 8.7 +/- 3.7 mm (P < 0.001 compared with post-BD diameter). Stents increased the diameter in all arteries and made four of four failed BD successful. In the two most recent procedures, stents were placed without prior BD with diameter increasing from 1.3 to 9 mm and 8.2 to 14 mm. A stent was placed in 1 of 7 arteries prior to 1993 and in 10 of 12 arteries thereafter (P < 0.004). Three patients prior to 1995 had catheterization-related deaths secondary to vessel rupture after BD. BD produces SD in approximately one-half of the procedures but is associated with mortality. Stent placement increases vessel diameter substantially more than BD alone. Stents reduce the acute complication rate and avoid early reoperation in this patient group.

Interventions for aortic coarctation

The standard treatment of coarctation of the aorta is surgical. In the last 2 decades, however, treatment by catheter intervention has become more widespread, using either balloon angioplasty or primary stent implantation. Balloon angioplasty was originally used for recurrent coarctation after surgical repair but has now been shown equally effective for unoperated coarctation. The procedure produces a satisfactory gradient reduction in approximately 80% of patients, with transverse arch hypoplasia the main predictor of poorer outcome. Rates of restenosis and aneurysm formation are less than 10%. Primary stent implantation has been suggested as an option potentially superior to angioplasty alone. Stent implantation limits elastic recoil and potentially reduces aneurysm formation by reducing the amount of balloon stretch required. The incidence of suboptimal gradient reduction is low, probably 5% or less, as is the rate of restenosis. Aneurysm formation, vascular complications, and stent migration also occur in less than 5%. Catheter interventions are now an established treatment strategy for coarctation, with a good success rate and safety profile. The outcome for native and recurrent coarctation appears similar. The authors believe that for most adult patients with coarctation of the aorta, catheter intervention should be offered as initial therapy.

Paraplegia following percutaneous balloon angioplasty of aortic coarctation: a case report

Balloon angioplasty of recurrent coarctation of the aorta is considered a low-risk procedure with high success rate. In the literature, the major complications are death, rupture of the aorta, recoarctation, aneurysm formation, cerebrovascular accident, and femoral artery thrombosis. Spinal cord ischemia as an unusual complication of balloon angioplasty is reported.

Intravascular ultrasound assessment of pulmonary vascular disease in patients with pulmonary hypertension

BACKGROUND

Measurements of pulmonary pressure and resistance are still considered to be the "gold standard" in the evaluation of pulmonary hypertension (PH), despite their limitations in predicting irreversible disease. Hemodynamic assessment also only provides a global evaluation of the pulmonary vascular bed, whereas PH is an inhomogeneous disease of the vessel wall.

METHODS AND RESULTS

We assessed the value of intravascular ultrasound (IVUS) in 30 patients with suspected PH and correlated the structural changes in distal pulmonary arteries found on IVUS with conventional hemodynamic data. Plasma endothelin (ET)-1 levels and pulmonary ET-1 extraction also were measured as markers of the severity of PH. The anatomic abnormalities revealed by IVUS were more severe in the lower lobes than in the upper lobes, as evidenced by the greater percentage of wall thickness (WT), the smaller lumen diameter/WT and lumen area/total vessel area (p < 0.05 for each). IVUS anatomic indexes correlated directly with hemodynamic data (eg, with pulmonary arterial systolic pressure; r = 0.56; p < 0.001) and ET-1 levels but inversely with pulmonary ET-1 extraction.

CONCLUSION

Patients with PH have greater pulmonary arterial WT that is more severe in the lower lobes than in the upper lobes. The severity of structural abnormalities found on IVUS is directly correlated with hemodynamic findings and ET-1 levels. IVUS may provide useful additional information in the assessment of patients with PH.

Balloon dilation for aortic recoarctation: morphology at the site of dilation and long-term efficacy

OBJECTIVES

We undertook this study to assess the immediate and long-term outcome of balloon angioplasty performed for recurrent or residual coarctation of the aorta, and to assess the changes in the vessel wall caused by this procedure.

METHODS

Clinical, echocardiographic, angiographic and hemodynamic data from 71 patients who underwent balloon angioplasty for recoarctation between January 1987 and January 1998 were analysed retrospectively.

RESULTS

Angioplasty was performed after a median of 82.6 months (range 1.4 mo-20.9 y, mean 88.5 mo) following surgery for coarctation. Mean systolic pressure gradients were reduced from 27 +/- 15 mmHg to 11 +/- 11 mmHg after angioplasty (p < 0.0001). The mean diameter at the site of recoarctation increased from 5.5 +/- 2.5 to 7.5 +/- 2.7 mm (p < 0.0001). Outpouchings of contrast agents, indicating the disruption of the inner layers of the vessel wall, were defined as extravasations. They were observed in one-quarter of the angiograms performed immediately after the intervention. Immediate success of angioplasty was achieved in 71%, and persisted in 69% of patients during long-term follow up. The main determinant for immediate success was the age at the time of the procedure (p < 0.05), while the main determinant for long-term success was the increase achieved in diameter. Extravasations did not progress to aneurysms, neither acutely nor during echocardiographic follow-up studies. For further follow-up, more sensitive imaging techniques will be necessary to delineate the morphology of the site of extravasation observed immediately after angioplasty.

Stent implantation for aortic coarctation and recoarctation

OBJECTIVE

To determine the early results of balloon expandable stent implantation for aortic coarctation or recoarctation.

DESIGN

Prospective observational study.

SETTING

Two paediatric cardiology tertiary referral centres.

PATIENTS

17 patients, median age 17 years (range 4.4 to 45) and median weight 61 kg (17 to 92). Six had native aortic coarctation and 11 had aortic recoarctation; 14 had upper limb systolic hypertension. Of those with recoarctation, eight had had at least one previous balloon dilatation attempt and two of these patients also had further surgical interventions.

INTERVENTION

Balloon expandable Palmaz iliac stent implantation.

MAIN OUTCOME MEASURES

Systolic pressures gradients, minimum aortic diameter, upper limb blood pressures, and incidence of aneurysm formation.

RESULTS

18 stents were implanted during 18 procedures in the 17 patients. Mean peak systolic pressure gradient fell from 26 mm Hg (95% confidence interval (CI), 21 to 31 mm Hg) before to 5 mm Hg (2 to 8 mm Hg) after stent implantation (p < 0.001), and mean minimum aortic diameter increased from 7 mm (95% CI, 6 to 8 mm) before to 11.3 mm (10 to 12.6 mm) after implantation (p < 0.001). Complications occurred in five patients (bleeding in two, stent migration in two, and aneurysm formation in one). Two patients remained borderline hypertensive and eight were receiving antihypertensive treatment at most recent assessment.

CONCLUSIONS

Stent implantation for aortic recoarctation and native coarctation gives good immediate results. Careful follow up is necessary to evaluate complications and the long term effect on blood pressure.