Balloon angioplasty of postsurgical recoarctation in infants: the risk of restenosis and long-term follow-up

Diastolic velocity half time is associated with aortic coarctation gradient at catheterization independent of echocardiographic and clinical blood pressure gradients

OBJECTIVE

The most accurate noninvasive parameter to predict whether a patient with aortic coarctation will meet interventional criteria at catheterization remains elusive. We aim to determine the best independent echocardiographic predictors of a coarctation peak-to-peak pressure gradient ≥20 mm Hg at catheterization, the accepted threshold for intervention.

DESIGN

Retrospective query of our catheterization database from 1/2007 to 7/2016 for the diagnostic code of aortic coarctation was performed. Multiple echocardiographic measurements and blood pressure gradients prior to cardiac catheterization were collected. Univariate correlation of variables with the continuous catheterization peak were calculated using Spearman's rho. Univariate association with peak-to-peak gradient at catheterization ≥20 mm Hg was tested using Mann-Whitney U test and the Pearson chi-square test or Fisher's exact test. Multivariable logistic regression assessed the independent association of the clinically relevant metrics with gradient at catheterization ≥20 mm Hg.

RESULTS

Sixty-eight patients met study criteria (median age 9.25 years), of whom 84% underwent intervention at catheterization. Echocardiographic peak and mean coarctation velocity, indexed systolic and diastolic velocity half times (SVHTi, DVHTi), and blood pressure gradient all had moderate correlation (Spearman's rho = 0.529-0.617, P < .001) with the continuous catheterization gradient and were significantly associated with the binary outcome of catheterization peak ≥20 mm Hg (P < .001). Logistic regression found echocardiographic mean systolic gradient (OR 1.213 [95% CI 1.041-1.414]) and DVHTi (OR 1.039 [95% CI 1.004-1.074]) independently associate with catheterization peak ≥20 mm Hg after controlling for blood pressure gradient (OR 1.066 [0.987-1.150]).

CONCLUSIONS

Most echocardiographic estimates show moderate correlation with arch gradient at catheterization. Noninvasive four extremity blood pressure gradient is significantly associated with peak-to-peak gradient ≥20 mm Hg. DVHTi may provide a unique independently associated echocardiographic estimate of coarctation severity. Further study of these variables with larger cohorts may allow for development of predictive models to direct catheterization.

The role of aortic compliance in determination of coarctation severity: Lumped parameter modeling, in vitro study and clinical evaluation

Early detection and accurate estimation of the extent of coarctation of the aorta (COA) is critical to long-term outcome. Peak-to-peak trans-coarctation pressure gradient (PKdP) higher than 20mmHg is an indication for interventional/surgical repair. Patients with COA have reduced proximal and distal aortic compliances. A comprehensive study investigating the effects of variations of proximal COA and systemic compliances on PKdP, and consequently on the COA severity evaluation has never been done. This study evaluates the effect of aortic compliance on diagnostic accuracy of PKdP. Lumped parameter modeling and in vitro experiments were performed for COA severities of 50%, 75% and 90% by area. Modeling and in vitro results were validated against retrospective clinical data of PKdP, measured in 54 patients with COA. Modeling and in vitro. PKdP increases with reduced proximal COA compliance (+36%, +38% and +53% for COA severities of 50%, 75% and 90%, respectively; p<0.05), but decreases with reduced systemic compliance (-62%, -41% and -36% for COA severities of 50%, 75% and 90%, respectively; p<0.01). Clinical study. PKdP has a modest correlation with COA severity (R=0.29). The main determinants of PKdP are COA severity, stroke volume index and systemic compliance. Systemic compliance was found to be as influential as COA severity in PKdP determination (R=0.30 vs. R =0.34). In conclusion, PKdP is highly influenced by both stroke volume index and arterial compliance. Low values of PKdP cannot be used to exclude the severe COA presence since COA severity may be masked by reduced systemic compliance and/or low flow conditions.

Recurrent coarctation: interventional techniques and results

Coarctation of the aorta (CoA) accounts for 5% to 8% of all congenital heart defects. With all forms of interventions for native CoA, repeat intervention may be required due to restenosis and/or aneurysm formation. Restenosis rates vary from 5% to 24% and are higher in infants and children and in those with arch hypoplasia. Although repeat surgery can be done for recurrent CoA, guidelines from a number of professional societies have recommended balloon angioplasty with or without stenting as the preferred intervention for patients with isolated recoarctation. For infants and young children with recurrent coarctation, balloon angioplasty has been shown to be safe and effective with low incidence of complications. However, the rates of restenosis and reinterventions are high with balloon angioplasty alone. Endovascular stent placement is indicated, either electively in adults or as a bailout procedure in those who develop a complication such as dissection or intimal tear after balloon angioplasty. Conventionally bare metal stents are used; these can be dilated later if required. Covered stents, introduced more recently, are best reserved for those who have aneurysm at the site of previous repair or who develop a complication such as aortic wall perforation or tear. Stents produce complete abolition of gradients across the coarct segment in a majority of cases with good opening of the lumen on angiography. The long-term results are better than that of balloon angioplasty alone, with very low rates of restenosis. However, endovascular stenting is a technically demanding procedure and can be associated with serious complications rarely.

Percutaneous angioplasty used to manage native and recurrent coarctation of the aorta in infants younger than 1 year: immediate and midterm results

Balloon angioplasty (BAP) used to manage native coarctation of the aorta (CoAo) in infants remains controversial. This study aimed to compare short- and midterm results of BAP between native CoAo (NaCo) and postsurgical recoarctations (ReCo) in infants younger than 1 year. This retrospective study compared the clinical, echocardiographic, hemodynamic, and angiographic data for infants who underwent BAP between July 2003 and September 2012. The 12 NaCo and 13 ReCo patients in this study underwent BAP at 4.61 ± 3.69 and 4.88 ± 3.07 months (p = 0.84) and weighed 5.49 ± 2.57 and 6.10 ± 2.11 kg (p = 0.52), respectively. Their respective heights were 60.58 ± 10.58 and 61.15 ± 6.74 cm (p = 0.87). All the ReCo patients had their initial surgery before the age of 3 months. The minimal CoAo diameter was 2.81 ± 0.96 mm in the NaCo group and 2.86 ± 1.0 mm in the ReCo group (p = 0.90). The relative gradient reduction was 62.79 ± 32.43 % in the NaCo group and 73.37 ± 20.78 % in the ReCo group (p = 0.33). The in situ complication rate (pseudoaneurysm) was 8.33 % in the NaCo group and 7.69 % in the ReCo group (p = 0.74). During the early follow-up evaluation, five NaCo patients (41.66 %) presented with recoarctation requiring BAP reintervention within 1.75 ± 1.41 months (all had their initial BAP before 3 months of age) compared with 1 ReCo patient (7.69 %) (p = 0.165). The mean follow-up period was 3.09 ± 2.69 years for the NaCo patients and 3.6 ± 3.18 years for the ReCo patients (p = 0.69), during which the blood pressure gradient was 12.33 ± 9.67 for the NaCo patients and 7.80 ± 8.78 for the ReCo patients (p = 0.17), with corresponding Doppler peak instantaneous gradients of 21.29 ± 11.19 and 16.20 ± 10.23 (p = 0.24). The resultant diameter ratio between the minimal isthmus diameter and the aortic diameter at the diaphragmatic level was 0.81 ± 0.15 in the NaCo group and 0.85 ± 0.12 in the ReCo group (p = 0.53). The immediate and midterm results of BAP for the NaCo and ReCo infants were comparable. Accordingly, BAP seems to be an acceptable alternative to surgery for infants older than 3 months.

Does the z-score value of the abdominal aorta predict recoarctation in an infant?

OBJECTIVE

We evaluated left ventricular dimensions and aortic arch z-scores in infants who underwent balloon angioplasty (BAP) or surgery for coarctation of aorta (CoA). We searched for risk factors predicting recoarctation.

PATIENTS

Between 2007-2011, 27 male and 17 female infants (mean age 2.93 ± 4.78 months, range 2 days-24 months) with CoA were evaluated. Left ventricular dimensions, systolic functions, mitral and aortic annuli, transverse aortic arch, isthmus, coarctation site, and diaphragmatic aorta measurements were done and z-scores were determined before intervention.

RESULTS

Six patients underwent primary operation, 38 patients had BAP (86.4%). Associated cardiac pathologies in operated patients were double outlet right ventricle (n = 2), atrioventricular septal defect (n = 1), Ebstein's anomaly (n = 1), arch hypoplasia (n = 2). Twelve patients (27.2%) had simple coarctation. Ventricular septal defect was the most frequent associated cardiac pathology (n = 20, 45.4%). The patients were followed for 10.22 ± 8.21 months. Among 33 primary successful BAP's, 14 had recoarctation (42%). Eleven patients were primarily operated (including 5 with unsuccessful BAP), two had recoarctation (18%). Abdominal and transverse aorta values and z-scores were significantly lower in the recoarctation group (7.15 ± 2.12 mm and 6.07 ± 1.86 mm respectively in the "no-recoarctation group"; vs. 5.53 ± 0.75 mm and 4.94 ± 1.53 mm in the "recoarctation group" P <.05). Abdominal aorta z-score of 0.42 was 88.9% sensitive and 53.8% specific to predict recoarctation (area under ROC curve: 0.618-0.902, P <.05).

CONCLUSION

Although BAP for native coarctation is still a controversial treatment option due to frequent restenosis rates, abdominal aorta z-score of 0.42 could correctly eliminate recoarctation in 89% of these cases. This cutoff value might help us choose patients for primary BAP and decrease the recoarctation rate after BAP.

Stenting Options for Coarctation of the Aorta

The narrowing of the lumen in coarctation of the aorta can be relieved with a high degree of immediate success by transcatheter methods. All methods are associated with immediate and longer-term complications, including dissection, aneurysm formation, and recoarctation. The introduction of the use of covered stents in aortic coarctation is encouraging because the material cover provides additional protection to the acutely disrupted aortic wall and can provide long-term protection of the dilated segment and the downstream area of poststenotic dilation. This review discusses the currently available options for stenting aortic coarctation.

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.

Endovascular management of coarctation of the aorta

Untreated thoracic aortic coarctation leads to early death predominantly because of hypertension and its cardiovascular sequelae. Surgical treatment has been available for > 50 years and has improved hypertension and survival. More recently, endovascular techniques have offered a minimally invasive alternative to traditional open repair. Early and intermediate results suggest angioplasty and stenting have an important role in the management of aortic coarctation, particularly in adults and older children.

The role of stents in the treatment of congenital heart disease: Current status and future perspectives

Intravascular or intracardiac stenoses occur in many forms of congenital heart disease (CHD). Therefore, the implantation of stents has become an accepted interventional procedure for stenotic lesions in pediatric cardiology. Furthermore, stents are know to be used to exclude vessel aneurysm or to ensure patency of existing or newly created intracardiac communications. With the further refinement of the first generation of devices, a variety of "modern" stents with different design characteristics have evolved. Despite the tremendous technical improvement over the last 20 years, the "ideal stent" has not yet been developed. Therefore, the pediatric interventionalist has to decide which stent is suitable for each lesion. On this basis, currently available stents are discussed in regard to their advantages and disadvantages for common application in CHD. New concepts and designs developed to overcome some of the existing problems, like the failure of adaptation to somatic growth, are presented. Thus, in the future, biodegradable or growth stents might replace the currently used generation of stents. This might truly lead to widening indications for the use of stents in the treatment of CHD.

Covered stents in the management of coarctation of the aorta in the adult: initial results and 1-year angiographic and hemodynamic follow-up

BACKGROUND

The purpose of this study was to determine the safety and efficacy of the Cheatham Platinum covered stent in adults with coarctation of the aorta.

METHODS

Adults with native coarctations (n=14); previous coarctation surgery (n=4), stenting (n=1) or both surgery and endovascular therapy (n=3) underwent percutaneous intervention with a covered stent. Indications for stenting in those with previous intervention were recurrent coarctation (n=4), aneurysm formation at the site of previous intervention (n=2) or both recurrent coarctation and aneurysm formation (n=2).

RESULTS

Twenty-three covered stents were placed in 22 patients (mean age 39+/-14 years, n=11 males). Successful device deployment was achieved in all patients, although one patient required a second covered stent for aortic wall rupture. Peak systolic gradient across the coarctation site decreased from 29+/-17 to 3+/-5 mm Hg (p<0.001) immediately following implant and this was maintained (6+/-9 mm Hg, p=0.001) at invasive assessment, 12 months after the initial procedure. Right arm systolic blood pressure significantly declined (p=0.02), as did the number of antihypertensive medications per patient (p=0.03). At angiographic follow-up, post-stenotic dilatation of the aorta decreased from 32+/-8 mm to 30+/-8 mm (p=0.001), however, no stent recoil was observed.

CONCLUSIONS

Covered stents are safe, durable and efficacious in the management of coarctation of the aorta. Angiography and hemodynamic assessment is an effective method of screening for recurrent coarctation, and arch and vascular complications after stenting in adults.

Management of systemic hypertension in children and adolescents: An update

Identification and treatment of hypertension should be an important focus of physicians caring for children. Ultimately, a link between hypertension in children and the risk of cardiovascular disease will be established. Further long-term studies are likely to show that morbidity and mortality will be decreased by the institution of treatment of hypertension in children. Additional risk factors such as obesity and lipid disorders should be sought and targeted for treatment as well. Lifestyle modifications are advised for all patients and can be tried solely for those with blood pressures between the 95th and 99th percentiles. Drug therapy is indicated in children with blood pressures greater than the 99th percentile, secondary hypertension, coexisting diabetes, left ventricular hypertrophy, or those who fail a trial of nonpharmacologic treatment. Children with white coat hypertension should not be treated with drugs. Children with renal artery stenosis and drug-refractory hypertension should be considered for percutaneous angioplasty or surgery depending on the anatomy of the lesion and operator experience. Children requiring multiple drug classes for control of blood pressure and older adolescents on one drug with renal artery lesions amenable to a percutaneous procedure may elect intervention in an attempt to reduce or eliminate drug therapy. Infants and children with hypertension due to native coarctation of the aorta should undergo surgical repair. Older children and adolescents with native coarctation should have surgical repair or percutaneous angioplasty/stenting. Hypertension secondary to recurrent coarctation is usually treated with a percutaneous intervention.

Coarctation of the aorta: stenting in children and adults

Coarctation of the aorta may present in infants, children, or adults, and it requires treatment to prevent serious morbidity and mortality. Recent advances in equipment and a growing collective experience have made placement of balloon-expandable stents a safe and effective alternative to surgery or angioplasty in a growing range of patients. This review seeks to provide a working aid for stenting of coarctation of the aorta, based on the techniques and technical considerations in practice at our institution. Between 1989 and 2005, the Congenital Cardiovascular Interventional Study Consortium (CCISC), a consortium of 17 centers, of which our institution is the largest contributor, performed 588 stent placements for coarctation of the aorta. Of the 588 procedures, 580 (98.6%) were successful, as defined by reduction of the gradient to less than 20 mm Hg or increase of the ratio of the diameter of the coarctation area (CoA) to the diameter of the descending aorta (DAo) to at least 0.8. There were a total of 84 complications occurring in 69/588 (11.7%) cases. The most common significant complications were femoral access vessel related 15/588 (2.6%), aneurysm formation 13/588 (2.2%), aortic dissection 9/588 (1.5%), and cerebrovascular accident 6/588 (1.0%). There were two procedure-related deaths (0.3%) recorded in the 16-year period. Many of these significant complications occurred in the same patients. Balloon-expandable stents should be considered a safe and very effective treatment modality in a significant subset of patients with coarctation of the aorta.

Endovascular stenting for aortic coarctation

Surgery had been the traditional treatment for native coarctation of the aorta, one of the most common cardiovascular congenital malformations. As a less invasive mode of treatment, balloon angioplasty has emerged as an alternative to surgery but has not gained universal acceptance due to its rates of restenosis secondary to vessel recoil and concerns over aortic wall injury resulting in aneurysm formation. To overcome these problems, endovascular stents were introduced in the management of this condition. The early- and intermediate-term results are encouraging, with low rates of restenosis and complications. In this article, the authors review the current evidence on coarctation stenting and discuss future trends in this area.

Covered Cheatham-platinum stents for aortic coarctation: early and intermediate-term results

OBJECTIVES

This study sought to evaluate the use of covered Cheatham-platinum (CP) stents in the treatment of aortic coarctation (CoA).

BACKGROUND

Aortic aneurysms and stent fractures have been encountered after surgical and transcatheter treatment for CoA. Covered stents have previously been used in the treatment of abdominal and thoracic aneurysms in adults. We implanted covered CP stents as a rescue treatment in patients with CoA aneurysms or previous stent-related complications and in patients at risk of developing complications because of complex CoA anatomy or advanced age.

METHODS

Thirty-three covered CP stents were implanted in 30 patients; 16 patients had had previous procedures. The remaining patients had complex or near-atretic CoA.

RESULTS

The mean patient age and weight were 28 (+/-17.5) years (range 8 to 65 years), and 62 (+/-13) kg (range 28 to 86 kg), respectively. The systolic gradient across the CoA decreased from a mean (+/-SD) of 36 +/- 20 mm Hg before to a mean of 4 +/- 4 mm Hg after the procedure (p < 0.0001), and the diameter of the CoA increased from 6.4 +/- 3.8 mm to 17.1 +/- 3.1 mm (p < 0.0001). The follow-up period was up to 40 months (mean, 11 months). All stents were patent and in good position on computed tomography or magnetic resonance imaging performed three to six months later. In 43% of the patients antihypertensive medication was either decreased or stopped.

CONCLUSIONS

Covered CP stents may be used as the therapy of choice in patients with complications after CoA repairs, whereas they provide a safe alternative to conventional stenting in patients with severe and complex CoA lesions or advanced age.

Magnetic resonance imaging predictors of coarctation severity

BACKGROUND

MRI is increasingly used for anatomic assessment of aortic coarctation (CoA), but its ability to predict the transcatheter pressure gradient, considered the reference standard for hemodynamic severity, has not been studied in detail. This study evaluated the ability of MRI to distinguish between mild versus moderate and severe CoA as determined by cardiac catheterization.

METHODS AND RESULTS

The clinical, MRI, and catheterization data of 31 subjects referred for assessment of native or recurrent CoA were reviewed retrospectively. Patients were divided into 2 groups on the basis of peak coarctation gradient by catheterization: <20 mm Hg (n=12) and > or =20 mm Hg (n=19). Patients with cardiac index <2.2 L x min(-1) x m(-2) by catheterization were excluded. By logistic regression analysis, the following variables simultaneously predicted coarctation gradient > or =20 mm Hg: (1) smallest aortic cross-sectional area (adjusted for body surface area) measured by planimetry from gadolinium-enhanced 3D magnetic resonance angiography (OR 1.71 for 10 mm2/m2 decrease, P=0.005) and (2) heart rate-corrected mean flow deceleration in the descending aorta measured by phase-velocity cine MRI (OR 1.68 for 100 mL/s(1.5) increase, P=0.018). For the combination of these variables, a predicted probability >0.38 had 95% sensitivity, 82% specificity, 90% positive and negative predictive values, and an area under the receiver-operator characteristics curve of 0.938. In a subsequent validation study, the prediction model correctly classified 9 of 10 patients, with no false-negatives.

CONCLUSIONS

The combination of anatomic and flow data obtained by MRI provides a sensitive and specific test for predicting catheterization gradient > or =20 mm Hg.

Histological findings after angioplasty using conventional balloon, radiofrequency thermal balloon, and stent for experimental aortic coarctation

BACKGROUND

Use of balloon angioplasty or stent implantation has been reported to be effective in relieving coarctation of the aorta. However, restenosis frequently occurs after balloon angioplasty for native aortic coarctation in small infants, and sometimes develops after stent implantation because of vessel growth. The causes of restenosis remain uncertain. The purpose of this study was to assess the histologic differences in vascular responses to angioplasty using conventional balloon, radiofrequency thermal balloon (RFTB), or stent for experimental aortic coarctation.

METHODS

The authors surgically created an aortic coarctation model using 14 puppies. Angioplasty using conventional balloon, RFTB, or stent was performed 1 month after the initial operation. At the acute or chronic phase after angioplasty, the animals were killed and histologic studies were performed.

RESULTS

More vascular injuries were noted in the specimens from animals undergoing conventional angioplasty than in those with RFTB or stent. However, neointimal hyperplasia was seen more often after RFTB or stent because of the proliferation of smooth muscle cells from the tunica media, caused by secretion of growth factors. Apoptosis reached a peak 1-2 weeks after angioplasty, regardless of the type of intervention.

CONCLUSIONS

The authors conclude that angioplasty with RFTB or stent can provide relatively small injuries in the vessel wall for aortic coarctation, but care must be taken to prevent restenosis caused by intimal hyperplasia, because neointima hyperplasia is more frequent after RFTB or stent.

Transcatheter intervention in the neonate with congenital heart disease

Over the past 30 years, interventional cardiology has developed as a distinct subspecialty, playing a major role in the management of infants with CHD. In the neonatal period, a wide variety of transcatheter interventions are performed routinely, either as palliation or therapy, as adjunct to surgery, or in place of surgical intervention. Among these are creation or enlargement of ASDs to allow atrial mixing; balloon valvotomy to treat congenital valvar stenoses; balloon angioplasty or stenting of stenotic vessels (pulmonary arteries, coarctation of aorta, or systemic or pulmonary veins) or postoperative anastomoses; closure of [figure: see text] unwanted vessels (congenital fistulae or collaterals); and other miscellaneous interventions. A wide variety of patients are candidates for these procedures, including those with transposition of the great arteries or other defects with transposition physiology, left atrial outlet obstruction and hypertension, severe valvar pulmonary or aortic stenosis, hypoplastic stenotic pulmonary arteries with severe symptomatology, severe coarctation of aorta and high surgical risks, large aortopulmonary collaterals or other hemodynamically significant unwanted vessels, acute thrombosis of certain surgical anastomoses, and many more. In experienced hands, these procedures are highly successful and safe, with a low morbidity and mortality (less than 1%).