Stent implantation for aortic coarctation and recoarctation

Medium-Term Outcomes of Stent Therapy for Aortic Coarctation in Children Under 30 kg with New Generation Low-Profile Stents: A Follow-Up Study of a Single Centre Experience

We previously reported short-term outcomes for stenting of aortic coarctation (CoA) (native or re-coarctation) with newer generation low-profile stents (Valeo, Formula, and Begraft stents) in children under 30 kg. We present here the medium-term outcomes of this procedure. Retrospective review of patients weighing under 30 kg who had percutaneous stent treatments for coarctation between 2012 and 2021 was performed. Clinical and procedural data were collected; 19 patients were included. The median age at the time of procedure was 5.1 [4.1-6.4] years and median weight 21.0 [17.3-22.3] kg. One patient had a history of re-coarctation. Thirteen (68%) patients were on anti-hypertensives pre-procedure. Different types of stents were used (14 Valeo™, 4 Formula® 535, 1 BeGraft), which can all be dilated to 18 mm or larger. One patient required a 9 F sheath, all others required a 7 F sheath. The narrowest diameter in the aorta increased from a median of 3.5 [3.0-4.5] to 9.4 [8.9-9.8] mm, p < 0.001; there was a reduction in the median pressure gradient across the coarctation from 35.0 [30.0-43.0] to 5.0 [0-10.0] mmHg, p < 0.001. There were no intra-procedural complications. Follow-up was for a median of 56.0 [13.0-65.0] months. Five (26%) of patients underwent re-intervention after a median time frame of 40.0 [39.5-52.0] months; four had balloon dilation, one had repeat stent implantation. Five (26%) patients were on anti-hypertensive agent(s) post-intervention. Our single centre experience demonstrates that percutaneous stenting for coarctation of aorta in children under 30 kg, with low-profile stents, had no significant complications during the median follow-up time of 56 months. This study demonstrated that the procedure is safe and effective for short and medium-term therapy in this group of patients with a 26% re-intervention rate. A quarter of patients remained on anti-hypertensive medication post stenting, emphasizing the importance of long-term follow-up.

Bioresorbable PPDO sliding-lock stents with optimized FDM parameters for congenital heart disease treatment

Stent implantation has been a promising therapy for congenital heart disease (CHD) due to better efficacy. Compared to permanent metal stents, bioresorbable polymer stents have shown a great advantage in accommodating the vascular growth of pediatric patients, but the application is still limited due to inferior radial strength. Here, bioresorbable poly(p-dioxanone) (PPDO) sliding-lock stents for CHD treatment were fabricated by fused deposition modeling (FDM). The effects of FDM processing parameters, including nozzle temperature, bed temperature, layer thickness, and printing speed, on the mechanical properties of PPDO parts were investigated to optimize the processing condition to enhance the radial strength of stents. Finite element analysis (FEA) was also used to evaluate the mechanical properties of stents. PPDO sliding-lock stents fabricated under optimized FDM parameters showed radial strength of 3.315 ± 0.590 N/mm, superior to benchmark commercial metal stents. Radial strength curve and compression behavior of PPDO sliding-lock stents were investigated. Results of FEA exhibited that strut width, shape of the mesh cell and surface coverage ratio had an impact on the compression force of PPDO sliding-lock stents. PPDO sliding-lock stents fabricated with optimized FDM parameters show favorable mechanical performance and meet the requirement of CHD treatment.

The effect of coarctation degrees on wall shear stress indices

Coarctation of the aorta (CoA) is a congenital tightening of the proximal descending aorta. Flow quantification can be immensely valuable for an early and accurate diagnosis. However, there is a lack of appropriate diagnostic approaches for a variety of cardiovascular diseases, such as CoA. An accurate understanding of the disease depends on measurements of the global haemodynamics (criteria for heart function) and also the local haemodynamics (detailed data on the dynamics of blood flow). Playing a significant role in clinical processes, wall shear stress (WSS) cannot be measured clinically; thus, computation tools are needed to give an insight into this crucial haemodynamic parameter. In the present study, in order to enable the progress of non-invasive approaches that quantify global and local haemodynamics for different CoA severities, innovative computational blueprint simulations that include fluid-solid interaction models are developed. Since there is no clear approach for managing the CoA regarding its severity, this study proposes the use of WSS indices and pressure gradient to better establish a framework for treatment procedures in CoA patients with different severities. This provides a platform for improving CoA therapy on a patient-specific level, in which physicians can perform treatment methods based on WSS indices on top of using a mere experience. Results show how severe CoA affects the aorta in comparison to the milder cases, which can give the medical community valuable information before and after any intervention.

Percutaneous Implantation of Adult Sized Stents for Coarctation of the Aorta in Children ≤20 kg: A 12-Year Experience

BACKGROUND

Stent implantation (SI) is more effective than balloon angioplasty for the treatment of coarctation of the aorta (CoA). Due to technical factors, balloon angioplasty is more commonly performed in small patients. We sought to evaluate outcomes of percutaneous adult sized SI for the treatment of CoA in small patients.

METHODS

A single-center retrospective review of all patients ≤20 kg who underwent percutaneous adult sized SI for native or recurrent CoA from 2004 to 2015 was performed.

RESULTS

Thirty-nine patients (20 patients ≤10 kg) were identified, with 28 (71.8%) having recurrent CoA and 22 (56.4%) previously failed balloon angioplasty. At the time of SI, the median (range) patient age and weight were 1.1 (0.3-7.9) years and 10 (5.5-20.4) kg, respectively. SI resulted in significant improvements in the median gradient (26 mm Hg [interquartile range (IQR), 18-42] to 0 mm Hg [IQR, 0-2]; P< 0.05) and median minimum diameter (3.6 mm [IQR, 2.4-4.8] to 7.7 mm [IQR, 6.5-9.4]; P<0.05). Seven patients (18%) had procedural adverse events. Twenty-seven (69%) patients underwent elective reintervention at a median time of 49.3 (IQR, 26.5-63.2) months from SI, with 8 (21%) stents requiring repeat SI for stent fracture. Over a median follow-up of 67.2 (IQR, 33.8-116.1) months, 25 patients (69%) were without hypertension or blood pressure gradient. Three (11%) patients developed femoral arterial occlusion.

CONCLUSIONS

Adult sized SI is an alternative to surgical intervention for small patients with CoA. SI carries a risk of access-related complications, which may improve with the development of lower profile stents with adult sized maximum diameters.

Management of adults with coarctation of aorta

Coarctation of the aorta (CoA) is a relatively common congenital cardiac defect often causing few symptoms and therefore can be challenging to diagnose. The hallmark finding on physical examination is upper extremity hypertension, and for this reason, CoA should be considered in any young hypertensive patient, justifying measurement of lower extremity blood pressure at least once in these individuals. The presence of a significant pressure gradient between the arms and legs is highly suggestive of the diagnosis. Early diagnosis and treatment are important as long-term data consistently demonstrate that patients with CoA have a reduced life expectancy and increased risk of cardiovascular complications. Surgical repair has traditionally been the mainstay of therapy for correction, although advances in endovascular technology with covered stents or stent grafts permit nonsurgical approaches for the management of older children and adults with native CoA and complications. Persistent hypertension and vascular dysfunction can lead to an increased risk of coronary disease, which, remains the greatest cause of long-term mortality. Thus, blood pressure control and periodic reassessment with transthoracic echocardiography and three-dimensional imaging (computed tomography or cardiac magnetic resonance) for should be performed regularly as cardiovascular complications may occur decades after the intervention.

Coarctation repair-redo challenges in the adults: what to do?

Aortic coarctation is one of the most common congenital cardiac pathologies. Repair of native aortic coarctation is nowadays a common and safe procedure. However, late complications, including re-coarctation and aneurysm formation, are not uncommon. The incidence of these complications is dependent on the type of the initial operation. Both endovascular and conventional open repair play important roles in the treatment of late complications after previous coarctation repair. This article will review the incidence of late complications after coarctation repair and will discuss the treatment options for redo coarctation repair in adult patients.

Stent Therapy for Aortic Coarctation in Children <30 kg: Use of the Low Profile Valeo Stent

To report our experience of coarctation stent therapy in small children weighing less than 30 kg, with the low profile dilatable Valeo stent and review the literature on coarctation stent therapy in this patient population. Coarctation stent implantation was undertaken in 14 consecutive children using the Bard Valeo Stent. Demographic, angiographic, echocardiographic and clinical data were reviewed retrospectively. The median age at the time of procedure was 5.1 (2.6-7.5) years and median weight was 20.8 (14.7-27) kg. There was improvement in median coarctation diameter from 4 (1.3-5.2) to 9.5 (5.8-12.7) mm, p < 0.001; and a reduction in the median peak pressure gradient across the coarctation from 35 (20-49) to 9 (0-15) mmHg, p < 0.001. Median stent recoil was 7.9 (0-20)%. There was one case of access related complication that resolved without sequelae. Follow-up was a median of 15 (3.0-57.2) months. CT angiogram performed at a median time of 3.3 (2.6-10.2) months post procedure showed no aortic wall injury and preserved stent integrity in all cases. Two children underwent re-intervention for stent dilation and further stent implantation due to in-stent stenosis and somatic growth after 3 years. Six of fourteen children remained on a single antihypertensive agent post-intervention at last follow-up. Implantation of the dilatable Valeo stent is a feasible treatment strategy in native or recurrent coarctation in small children, accepting that additional stent implantation may be necessary with somatic growth. Further study is required to determine longer-term stent efficacy and clinical outcome.

Use of the AndraStent XL and XXL for the treatment of coarctation of the aorta in children and adults: immediate and midterm results

AIMS

The aim of this study is to present our experience with a new type of extra-large stent, namely the AndraStent XL/XXL.

METHODS AND RESULTS

AndraStents were implanted in 46 patients, 38 with native coarctation of the aorta (CoA) and eight with recurrent coarctation of the aorta following previous surgery (ReCoA). All patients had arterial hypertension in the upper limbs, absent or weak femoral pulses, and continuous flow in the abdominal aorta on Doppler examination. The median age of patients was 25 years (range from nine to 65). The stents (cobalt-chromium with semi-open cell design) were manually mounted on balloon catheters and delivered through 10 to 14 Fr Mullins sheaths using a conventional femoral approach. All procedures were successful (no stent migration, proper expansion, no aorta dissection/rupture, major bleeding or major vessel injury). The systolic gradient across the aorta decreased from 40.6 mmHg before the procedure to 11.6 mmHg after the procedure (p<0.001). The mean fluoroscopy time was 5.7 minutes. Imaging examinations were scheduled and performed between six and 12 months after the initial procedure in 40 patients (angiography or angio CT or both). Procedural outcome remained favourable during a mean 2.4 years of follow-up. Neither stent fracture nor dislocation was observed in any patient at follow-up. In two patients, small aneurysm formation was observed six and eight months after the procedure -they were treated successfully with subsequent covered stent implantation. Re-dilatation of the implanted stent was performed between four and 26 months in 14 patients.

CONCLUSIONS

Implantation of new large cobalt-chromium stents is a good therapeutic option for the treatment of native and recurrent CoA.

Benefit of endovascular stenting for aortic coarctation on systemic hypertension in adults

BACKGROUND

Endovascular stenting is a recognised treatment strategy for aortic coarctation (CoA) in adults. We assessed systemic hypertension control and the need for antihypertensive therapy after CoA stenting in adults.

METHODS

Data were collected prospectively on 54 patients (36 men; mean age: 34 ± 16 years) who underwent endovascular stenting for CoA over a 7-year period. Five patients were excluded as they did not attend follow-up appointments. Patients underwent clinical examination, including right arm systolic blood pressure (SBP) and 24-hour ambulatory blood pressure monitoring at baseline, 6-12 weeks and 9-12 months.

RESULTS

There was a significant fall in mean peak-to-peak systolic gradient (PG) across the CoA after stenting (26 ± 11 mmHg vs. 5 ± 4 mmHg; P<0.01). There were successive reductions in right arm SBP and ambulatory SBP at baseline, 6-12 weeks and 9-12 months post-procedure (right arm: 155 ± 18 mmHg vs. 137 ± 17 mmHg vs. 142 ± 16 mmHg, respectively; all P-values <0.01; ambulatory: 142 ± 14 mmHg vs. 132 ± 16 mmHg vs. 131 ± 15 mmHg, respectively; all P-values <0.01). Twenty-four patients had severe CoA (PG >25 mmHg before stenting); baseline SBP was significantly higher in severe versus non-severe patients (160 mmHg vs. 148 mmHg; P=0.02). The absolute reduction in PG after stenting was significantly higher in the severe group (31 ± 7 mmHg vs. 14 ± 5 mmHg; P<0.0001), but there was no significant difference in SBP between groups at 6-12 weeks (141 mmHg vs. 135 mmHg; P=0.21) or 9-12 months (139 mmHg vs. 139 mmHg; P=0.96).

CONCLUSION

Endovascular stenting of CoA results in a significant reduction in SBP at 6-12 weeks, which is sustained at 9-12 months, with similar outcomes in severe and non-severe CoA groups.

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.

Current state of interventional cardiology in congenital heart disease

Congenital interventional cardiology seeks to provide alternative percutaneous solutions to congenital cardiac problems in preference to more traditional surgical approaches. Simpler procedures have been refined and are now achievable in smaller children and infants. More complex procedures are increasingly recognised as superior to surgical alternatives, though most patients with complex disease inevitably undergo combinations of interventional, surgical and joint or hybrid procedures. This review seeks to highlight recent advances in these techniques of most interest to the readership of this journal.

Quantification of local hemodynamic alterations caused by virtual implantation of three commercially available stents for the treatment of aortic coarctation

Patients with coarctation of the aorta (CoA) are prone to morbidity including atherosclerotic plaque that has been shown to correlate with altered wall shear stress (WSS) in the descending thoracic aorta (dAo). We created the first patient-specific computational fluid dynamics (CFD) model of a CoA patient treated by Palmaz stenting to date, and compared resulting WSS distributions to those from virtual implantation of Genesis XD and modified NuMED CP stents, also commonly used for CoA. CFD models were created from magnetic resonance imaging, fluoroscopy and blood pressure data. Simulations incorporated vessel deformation, downstream vascular resistance and compliance to match measured data and generate blood flow velocity and time-averaged WSS (TAWSS) results. TAWSS was quantified longitudinally and circumferentially in the stented region and dAo. While modest differences were seen in the distal portion of the stented region, marked differences were observed downstream along the posterior dAo and depended on stent type. The Genesis XD model had the least area of TAWSS values exceeding the threshold for platelet aggregation in vitro, followed by the Palmaz and NuMED CP stents. Alterations in local blood flow patterns and WSS imparted on the dAo appear to depend on the type of stent implanted for CoA. Following confirmation in larger studies, these findings may aid pediatric interventional cardiologists in selecting the most appropriate stent for each patient, and ultimately reduce long-term morbidity following treatment for CoA by stenting.

Role of stents in congenital heart disease

For more than 10 years, balloon-expandable intravascular stents have become an integral part of treatment for obstructive vascular lesions in children and adults with congenital heart disease. The initial problems with stents, such as sharp edges, rigid frame and unacceptable shortening when over-expanded have been overcome to a large extent with the newer designs. The problems related to delivery of stents, such as stent migration, balloon rupture, flaring of the edges of the stent, rupture of vessels and milking of the stent off the balloon, have also been overcome by newer designs of balloons. The failure of growth of balloon-expandable stents with the growth of the child is managed by redilation with or without additional stenting and newer growth stents. Self-expanding stents are not appropriate for use in growing children due to the limitation of their maximum diameters. The development of biodegradable stents may overcome these disadvantages in the future. Various new developments have recently occurred. Covered stents are ideal for treating acute vessel rupture and in isolating vascular aneurysms. Drug-eluting stents may prevent restenosis, but have not been used in children. Valved stents are a recent innovation for the treatment of regurgitant pulmonary valves.

Covered stents in the management of native coarctation of the aorta--intermediate and long-term follow-up

OBJECTIVES

To evaluate the results of covered Cheatham-Platinum stent implantation in the management of native coarctation of the aorta and report intermediate and long-term follow-up.

BACKGROUND

Covered stents are being used increasingly in severe and complex coarctation of the aorta mainly to reduce risk of aortic wall complications. There is, however, limited data on the intermediate and long-term outcome.

PATIENTS AND METHODS

Fifty-six patients received 59 covered Cheatham-Platinum stents (January 2002-December 2011) at a single center-in 54 patients as primary treatment and in 2 as a rescue. Mean age was 22.25 ± 1.2 (11-56) years and mean weight 58.6 ± 2.1 (32-99) kg. Primary end points were reduction in systolic pressure gradient and an increase in coarctation segment diameter. Changes in antihypertensive medicines and complications were recorded on follow-up.

RESULTS

Mean coarctation segment diameter increased from 4.69 ± 0.20 to 15.1 ± 3.2 mm (P < 0.0001). The systolic gradient decreased from mean of 51.4 ± 3.4 to 4.6 ± 0.7 mm Hg (P < 0.0001). There was one death 3 days postprocedure due to cerebral anoxia. There was one dissection diagnosed 24-hr postprocedure. At a mean follow-up of 45.9 ± 3.9 (3-120) months, all stents were patent and in good position on computed tomography. Four (7.1%) patients underwent successful redilation. Antihypertensive medication was decreased or stopped in 37 (66%) patients.

CONCLUSIONS

Covered Cheetham-Platinum stents may be used effectively as therapy of choice in selected patients with severe coarctation of the aorta. Aortic wall complications occur even with covered stents. Covered stents provide a safe alternative to conventional stenting in the intermediate and long-term and can be redilated safely to keep pace with somatic growth.

Effect of interventional stent treatment of native and recurrent coarctation of aorta on blood pressure

The aim of this study was to describe the clinical impact of management of coarctation of the aorta by transcatheter stent placement in the context of longer term management of systemic hypertension. In the long term, poor outlook associated with untreated coarctation of the aorta is likely to relate to uncontrolled systemic hypertension. Transcatheter stent placement to treat native and recurrent coarctation of the aorta is an established therapy in adolescents and adults. There remains confusion about longer term outcomes, particularly the relation between procedural success and improvement in blood pressure (BP) control. Improvement in lifelong systemic BP control after transcatheter stent placement remains unproved. Forty patients underwent transcatheter stent placement over a 10-year period (2001 to 2010) at the Yorkshire Heart Centre. The average age at the time of procedure was 25 years (range 14 to 57). There was a reduction in peak systolic gradient across the coarcted segment from 25 to <10 mm Hg in 35 of 39 patients. After stent placement, there was a significant improvement in systolic BP control at early and later follow-up (mean 155 mm Hg before the procedure and 134 mm Hg at 2.81-year follow-up, p <0.0001). There was 1 early procedural adverse event (stent embolization) and 1 late adverse event (lower limb claudication). In conclusion, transcatheter stent placement for the management of aortic coarctation is associated with a reduction in systolic BP that is maintained over the medium term. A significant minority of patients remain significantly hypertensive, and the best management strategy for this group of patients remains unclear.

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 repair of aortic isthmus coarctation with a self-expanding covered stent

BACKGROUND

Coarctation is one of the most often seen congenital aortal defects. In the majority, diagnosis will be made in newborns. Endovascular repair is critical in children owing to their growth, but in adult patients, it is an interesting alternative.

METHODS

A 31-year-old man presenting with hypertension of upper extremities and pulseless lower extremities was admitted to our hospital. Systolic blood pressure was 190 mm Hg, although a triple antihypertensive medication was administered. Computed tomographic angiography showed a nearly total occlusion of the aortic isthmus. Coarctation was treated by an endovascular approach with a self-expanding covered stent-graft (Medtronic Talent; Medtronic World Medical, Sunrise, FL) after predilatation with a Reliant balloon (Medtronic World Medical, Sunrise, FL).

RESULTS

After a follow-up of 40 months, the patient is normotensive and antihypertensive medication could be reduced. Lower extremities showed normal pulses and normal ankle-brachial index. Computed tomographic scans showed unchanged stent-graft position, with constant slight waist.

DISCUSSION

Endovascular repair of atresia or coarctation of the thoracic aorta is a minimal invasive debatable option. Not only reduction of blood pressure but also reduction of left ventricular mass and prolongation of life expectancy can be achieved by endovascular treatment.

The unusual hypertensive patient

Many young patients with systemic hypertension have secondary causes which if identified early could lessen the cardiovascular complications associated with long standing hypertension. Coarctation of the aorta is one of those rare causes. We describe a 40 year old male with hypertension, coarctation of the aorta, bicuspid aortic valve, PDA and an adrenal mass.

Results of stent implantation for native and recurrent coarctation of the aorta-follow-up of up to 13 years

BACKGROUND

To evaluate the mid and long-term prognosis after stenting of native or recurrent CoA, we studied the cardiovascular parameters in the follow-up period up to 13 years.

METHODS AND RESULTS

Between 1993 and 2006, 68 patients underwent stent implantation for aortic coarctation (average age 25.5 years, range 5.7-65 years, average weight 65.5 kg, range 32-122 kg). Forty-six (68%) patients were aged >17 years. Stenting was performed for native coarctation in 41 and for recurrent coarctation in 27 patients, in 23 (34%) patients with a covered stent. Redilation was carried out in 26 (38%) patients. The invasive systolic gradient decreased from mean (±SD) 25 (±15) mm Hg to 5 (±5) mm Hg (P < 0.0005). The descending aorta pressure increased from 80 (±15) mm Hg to 101 (±18) mm Hg. The systolic right arm blood pressure decreased from a mean of 153 (±24) mm Hg to 129 (±18) mm Hg (P < 0.0005). Complications like small dissections were rare. Follow-up (6 days to 13 years, mean 41 months) was available in 66 patients, in 23 after reintervention at a mean of 71 months, range of 8 months to 10.3 years. Fifty-one percent remained clinically hypertensive.

CONCLUSIONS

Stenting of aortic coarctation gives good medium-term results. Frequent reintervention relate to deliberately under-dilating stents during the initial procedure. The reintervention rate has reduced since the introduction of covered stents.

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.

Computational fluid dynamic simulations of aortic coarctation comparing the effects of surgical- and stent-based treatments on aortic compliance and ventricular workload

OBJECTIVES

In this work, we examine the effects of stent-induced aortic stiffness on cardiac workload and blood pressure using computational fluid dynamic simulations.

BACKGROUND

Treatment of aortic coarctation (CoA) consists of either open, surgical repair or angioplasty with or without stenting. Although stenting is a minimally invasive alternative to surgery, aortic stiffness increases in the stented section. Concern over this increased stiffness has long been argued to be detrimental to the overall vascular health of the patient.

METHODS

MR imaging was performed on a 15-year-old female with CoA. A 3D model of the large thoracic arteries was created, and the heart and downstream vasculature were represented by lumped parameter models at the model inlet and outlets, respectively. A deformable wall assumption was used in conjunction with variable wall properties and tissue support, and 3D velocity, pressure, and wall dynamics were computed. The lumped parameter values and wall properties were tuned to match the mean flow and aortic deformation as measured by MRI. The CoA was then virtually removed from the model representing an end-to-end surgical correction. In a second model, the repaired section was prescribed to be nearly rigid, representing stenting. All other variables remained the same.

RESULTS

When compared to surgery, stenting resulted in clinically negligible increases in cardiac work (0.4%) and no change in mean blood pressure.

CONCLUSIONS

This pilot study suggests CoA stenting may not affect cardiac work to any significant degree as is commonly believed in the clinical community.

Comparison of surgical and interventional therapy of native and recurrent aortic coarctation regarding different age groups during childhood

OBJECTIVE

The aim of the study was to analyze immediate results, rate of complications and re-interventions during medium-term outcome in pediatric patients with native or recurrent aortic coarctation. We focused on an age-related therapeutic approach comparing surgical and trans-catheter treatment.

METHODS

This is a retrospective, single-centre, clinical observational trial including 91 consecutive patients (age: 1 day-18 years) treated for native coarctation in 67 and recurrent aortic coarctation in 24 patients. Surgical treatment was performed in 56, trans-catheter treatment with balloon dilatation in 17, and by stent implantation in 18 patients. According to the age groups, we treated 48 children in group A (<6 months of age), 16 in group B (6 months-6 years), and 27 in group C (>6 years). A total of 41 patients in group A were operated (85%), patients in group B received either surgical or trans-catheter treatment (50% vs 50%), and 16 patients in group C were treated by stent implantation (62%).

RESULTS

Immediate results were excellent with a significant release of pressure gradient in all three age groups (64.7% in group A, 69.1% in group B, and 63.3% in group C). Complication rate and re-intervention rate (surgical and interventional) both were [corrected] comparable between the three age groups (complications: group A 8.3%, group B 6.3%, and group C 3.7%, [corrected] re-interventions: group A 16.6%, group B 18.8%, and group C 14.8%). [corrected] Midterm outcome after a median follow-up period of 17.5 months was satisfactory with a re-intervention-free survival after 17.5 months of 83.4%, 81.2%, and 81.5% in group A, group B, and group C, respectively.

CONCLUSIONS

The current strategy of an age-related therapy for native and recurrent aortic coarctation in our institution is surgery in infants <6 months (group A), either surgery or balloon dilatation in younger patients <6 years (group B), while in older children >6 years of age (group C) the trans-catheter treatment with stent implantation is an excellent alternative to surgery. Balloon dilatations showed limited results with an overall re-intervention rate of 53% and, therefore, should mainly be performed as a rescue procedure or in recurrent aortic coarctation in neonates.

Endovascular stenting for aortic (re)coarctation in adults

Objectives. Stenting for native and recurrent coarctation (COA) in adults has become an important therapeutic strategy. In this prospective observational study we evaluated the intermediate-term outcome of stent implantation for either native or recurrent (re)COA in adults.Methods. All adults who underwent stent implantation in our institution between January 2003 and December 2008 were included. Diagnosis of (re)COA was based upon a combination of clinical signs, noninvasive imaging or invasive gradient measurements. NuMED stents were implanted under general anaesthesia.Results. Twenty-four patients (50% male) underwent stent implantation for native (n=6) or reCOA (n=18) at a median age of 36 (18 to 60) years. There was significant improvement in pre- versus post-stent invasive systolic gradient (19 vs. 0 mmHg, p<0.001) and COA diameter (10 vs. 16 mm, p<0.001). Acute complications (12.5%) included death due to aortic rupture despite immediate successful coverage with a covered stent (n=1) and groin haematoma (n=2). During a median follow-up period of 33 (8 to 77) months (n=22), late complications occurred in three patients (13.6%): stent migration to the ascending aorta (n=1), pseudoaneurysm at the site of the initial stent (n=1), and occluded external iliac artery (n=1). Stent implantation did not reduce the need for antihypertensive medication or blood pressure at last follow-up. Conclusion. COA stenting results in a significant gradient decrease and increase in vessel diameter. However, serious complications do occur and hypertension remains in the majority of patients. (Neth Heart J 2010;18:430-6.).

Use of covered stents to treat coarctation of the aorta

Transcatheter treatments for coarctation of the aorta include balloon angioplasty and stent implantation. However, balloon angioplasty has its limitations and may be associated with complications, such as, recoarctation, dissection, and aneurysm formation, in adult patients. Bare metal stent implantation has offered an alternative during the last decade or so, but covered stents have been used with increasing frequency more recently, to the extent that covered stent implantation is the preferred treatment in correctly selected patients. Primary stent insertion, whether bare metal or covered, prevents elastic recoil of the aorta and may provide better and more predictable results than balloon angioplasty. Furthermore, stents are preferable for the treatment of complex aortic arch obstructions, but their usage is limited to older patients, because of limitations associated with growth.

Intravascular foreign bodies: danger of unretrieved fragmented medical devices

A warning on the danger of unretrieved device fragments and recommendations to mitigate the danger were issued by the Food and Drug Administration in January 2008. The causes of intravascular foreign bodies are classified into three main categories: improper manipulation and usage, device defects, and others, such as patient and anatomical factors. Device failure after long-term use is rarely predicted at the time of approval, since device abnormality is rarely experienced in animal studies and clinical trials conducted during development of the device. Stent fracture due to metal fatigue is one example. Complex complications could occur from simultaneous use of two or more devices with diverse characteristics. The success rate of percutaneous retrieval of intravascular foreign bodies has improved with the advances in commercially available devices. However, the procedure is not always successful and sometimes surgical removal becomes necessary. Appropriate device selection and acquisition of experience in using the device are important. When an intravascular foreign body cannot be retrieved, the risk of complication could be high. Magnetic resonance imaging examination sometimes causes adverse events, including burns due to the heat generated by metal movement. Such information should be correctly recorded. Furthermore, it is necessary to provide patients with adequate information about the characteristics of implanted devices and unretrieved fragments. We reviewed the literature on unretrieved medical device fragments and include articles that describe the Japanese experience.

Pediatric cardiac interventions

The field of pediatric cardiac interventions has witnessed a dramatic increase in the number and type of procedures performed. We review the most common procedures performed in the catheter laboratory. Lesions are divided according to their physiological characteristics into left-to-right shunting lesions (atrial septal defect, patent ductus arteriosus, ventricular septal defect), right-to-left shunting lesions (pulmonary stenosis, pulmonary atresia/intact ventricular septum), right heart obstructive lesions (peripheral arterial pulmonic stenosis, right ventricular outflow tract obstruction), and left heart obstructive lesions (aortic valve stenosis, coarctation of the aorta). In addition, a miscellaneous group of lesions is discussed.

Self-expanding nitinol stent implantation for treatment of aortic coarctation

PURPOSE

To prospectively assess the efficacy of self-expanding nitinol aortic stents in the treatment of coarctation of the aorta (CoA).

METHODS

Between July 2005 and July 2008, 21 patients (14 men; mean age 19.2+/-5.5 years, range 11-34) with CoA were treated with self-expanding Sinus-Aorta stents. The predilation balloon was selected to be <5 times the stenosis diameter. The stent diameter was selected to be 20% to 30% greater than the diameter of the undiseased aorta at the level of the diaphragm.

RESULTS

All procedures were successfully performed without any major complications. Predilation (mean balloon diameter 12.3 mm) and postdilation (mean balloon diameter 15.4 mm) were performed in 12 and 14 procedures, respectively. The mean diameter of the stents was 21.6+/-2.3 mm (range 18-26). The mean peak transcoarctation pressure gradient decreased from 57.4+/-19.5 mmHg (range 30-100) before the procedure to 1.2+/-2.2 mmHg (range 0-7; p<0.001). Cephalad stent dislodgement with the first-generation device occurred in 3 of 12 patients; 2 were treated with a second stent overlapping the first, and the third received 3 overlapped stents after the second stent migrated distally. No stent dislodgement occurred in the subsequent 9 patients treated with longer second-generation stents with anti-jump markers. None of the patients had dissection, arterial rupture, or other complications. On follow-up, 1 (5%) patient had recoarctation and minor stent migration after 18 months; another stent was deployed successfully. No evidence of aneurysm formation was seen in 7 patients undergoing arch imaging.

CONCLUSION

CoA can be successfully and safely managed with self-expanding nitinol aortic stents without aortic wall complications. Stent malpositioning can be overcome using oversized stents with anti-jump markers.

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.

Morphometric analysis of aortic coarctation: determination of the target vessel diameter required to relieve the pressure gradient

BACKGROUND

Little is known about the precise morphometric data of the aortic arch at which the transcatheter pressure gradient is relieved in patients with aortic coarctation (CoA).

METHODS AND RESULTS

Twenty-nine morphometric data were obtained from patients with CoA including the body surface area (BSA) adjusted angiographic diameter of the narrowest vessel, the ratio of the angiographic diameter to that of the descending aorta and BSA-adjusted narrowest cross-sectional area (CSA) using intravascular ultrasound imaging. The transcatheter peak-to-peak pressure gradient of the aortic arch was measured using a manometer tipped catheter. A linear regression analysis showed CSA to have the strongest correlation with the pressure gradient (r=0.92, p=0.0002) among any pressure gradient group (n=10). A receiver-operating characteristic curve (ROC) analysis was performed to determine the morphometric cut-off point at which the pressure gradient occurs. CSA had the highest areas under the ROC (1.0) and the cut-off point of 81 mm2/m2 showed a sensitivity of 100% and specificity of 100% to predict the relief of a pressure gradient.

CONCLUSIONS

In patients with CoA, the vessel size that can relieve a pressure gradient is a CSA of 81 mm2/m2 (10 x BSA0.5 mm in diameter). This data may provide useful information for catheter intervention and surgery.

Intermediate follow-up following intravascular stenting for treatment of coarctation of the aorta

BACKGROUND

We report a multiinstitutional study on intermediate-term outcome of intravascular stenting for treatment of coarctation of the aorta using integrated arch imaging (IAI) techniques.

METHODS AND RESULTS

Medical records of 578 patients from 17 institutions were reviewed. A total of 588 procedures were performed between May 1989 and Aug 2005. About 27% (160/588) procedures were followed up by further IAI of their aorta (MRI/CT/repeat cardiac catheterization) after initial stent procedures. Abnormal imaging studies included: the presence of dissection or aneurysm formation, stent fracture, or the presence of reobstruction within the stent (instent restenosis or significant intimal build-up within the stent). Forty-one abnormal imaging studies were reported in the intermediate follow-up at median 12 months (0.5-92 months). Smaller postintervention of the aorta (CoA) diameter and an increased persistent systolic pressure gradient were associated with encountering abnormal follow-up imaging studies. Aortic wall abnormalities included dissections (n = 5) and aneurysm (n = 13). The risk of encountering aortic wall abnormalities increased with larger percent increase in CoA diameter poststent implant, increasing balloon/coarc ratio, and performing prestent angioplasty. Stent restenosis was observed in 5/6 parts encountering stent fracture and neointimal buildup (n = 16). Small CoA diameter poststent implant and increased poststent residual pressure gradient increased the likelihood of encountering instent restenosis at intermediate follow-up.

CONCLUSIONS

Abnormalities were observed at intermediate follow-up following IS placement for treatment of native and recurrent coarctation of the aorta. Not exceeding a balloon:coarctation ratio of 3.5 and avoidance of prestent angioplasty decreased the likelihood of encountering an abnormal follow-up imaging study in patients undergoing intravascular stent placement for the treatment of coarctation of the aorta. We recommend IAI for all patients undergoing IS placement for treatment of CoA.

The adult with repaired coarctation of the aorta

Coarctation of the aorta is a common congenital lesion that may often be repaired or intervened upon early in life. The management of patients with this disorder revolves around the concept that although the coarctation may be treated, what remains is a diffuse systemic cardiovascular disorder. Careful clinical care and investigation is required to reduce morbidity from recurrent disease and residual lesions. The natural and modified history of the disorder is reviewed. This article focuses on the clinical care of adults with repaired coarctation and includes a review of clinical goals and investigation as well as indications for reintervention.

Effect of endovascular stenting of aortic coarctation on biventricular function in adults

OBJECTIVE

To investigate the effect of endovascular stenting of aortic coarctation on biventricular function in adults during intermediate-term follow-up.

METHODS

21 patients (age 34 (10) years) were studied prospectively before and 14 (2) months after coarctation stenting from year 2002 to 2005. Biventricular function and blood pressure measurements were made. The post-stenting results were compared with pre-stenting values (group 1), with 22 age- and sex-matched post-surgical repair patients (group 2) and 30 normal controls (group 3).

RESULTS

The peak systolic gradient across the coarctation site fell (55 (15) mm Hg to 18 (8) mm Hg, p<0.001). Systolic, mean blood pressure and left ventricular (LV) mass dropped after stenting (p<0.05 for all). LV long-axis function improved at intermediate-term follow-up (tissue Doppler imaging lateral and septal systolic and diastolic velocities and E/Em ratios: LSm, 6.5 (1.4) cm/s to 7.9 (1.7) cm/s; SSm, 5.8 (1.2) cm/s to 7.3 (1.6) cm/s; LEm, 8.1 (1.3) to 9.4 (2.3) cm/s; SEm, 6.7 (1.5) cm/s to 7.8 (1.9) cm/s; LE/Em, 11.2 (2.7) to 9.8 (2.8); SE/Em, 14.8 (5.3) to 11.8 (3.9); p<0.05 for all). No significant difference in LV ejection fraction, conventional LV diastolic measurements (E, A, E/A ratio, IVRT and DT) was found after stenting. No significant deterioration of right ventricular function was seen in stented patients. Both post-stenting and post-surgical repair patients had poorer LV long-axis function than controls (p<0.01 for all).

CONCLUSIONS

Endovascular stenting of aortic coarctation resulted in medium-term LV mass regression and long-axis function improvement that may provide insight into long-term outcome of the stented patients. The results support aortic stenting in patients with anatomically suitable defects, given the additional benefit of avoiding cardiopulmonary bypass. The clinical significance of subclinical myocardial dysfunction in patients with stented or repaired coarctation warrants further studies.

Development of a reexpandable covered stent for children

The use of covered stents in children is limited by the need for a large long sheath for delivery and the impossibility of redilation once implanted. The authors developed a reexpandable covered stent implantable in children through a small sheath and evaluated its clinical feasibility in mini piglets. An original Palmaz stent was covered with a polyurethane membrane that could be stretched up to 700%. Under general anesthesia, the authors implanted the covered stents in six mini piglets using a long sheath with a diameter approximately 1 French larger than the recommended size required to deliver an uncovered Palmaz stent. The implantation technique was similar to conventional stent implantation. In six piglets, the stent could be redilated from 7.5 to 8.7 mm 28-70 days after implantation. Macroscopic and microscopic examination showed intimal coverage of the coating with minimal inflammatory reaction around the stent. Our newly designed reexpandable stent covered with a polyurethane membrane is promising for use in children.

Acute and intermediate outcomes, and evaluation of injury to the aortic wall, as based on 15 years experience of implanting stents to treat aortic coarctation

BACKGROUND

Stenting for aortic coarctation has been shown to be effective in the short term. The safety and longer term efficacy of transcatheter therapy, however, must be well established if the technique is to be widely accepted as an alternative to surgery. In order to determine the frequency, spectrum, and outcome of injury to the aortic wall caused by angioplasty or stenting of aortic coarctation, the nomenclature of mural injury in these patients must be adapted to the conditions of transcatheter therapy.

METHODS AND RESULTS

Between 1989 and July 2005, we inserted stents in 153 patients with aortic coarctation, their median age being 15.8 years. Prior aortic interventions had been performed in 98 patients, and preexisting aneurysms were observed in 19. Stenting resulted in a significant reduction of the gradient across the site of coarctation, from a median of 30 millimetres of mercury to zero (p less than 0.001), with a residual gradient within the aortic arch of 20 millimetres of mercury or more in 5% of patients. Acute injuries to the aortic wall, other than therapeutic tears, were observed in 3 patients (2%), none of whom required surgery. At median follow-up of 2.5 years, this being more than 5 years in 30 patients, 4 patients had died, albeit none from complications relating to stenting or catheterization. Acute injuries to the aortic wall did not progress, and new aneurysms were observed in 6% of patients subsequent to follow-up imaging. Stent fractures, and jailed or partially covered brachiocephalic vessels, were observed in 12, and 49, patients, respectively, but did not result in haemodynamic or embolic complications.

CONCLUSIONS

Stenting for aortic coarctation results in consistent relief of the gradient, and few serious complications in the short and intermediate term. Serious injuries to the aortic wall are uncommon in our experience, and can be minimized with a focus on technical measures, such as pre-dilation before stenting.