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Interventional Pediatric Cardiology:
What Should we Abandon and Continue to Use

Ziyad M. Hijazi, M.D., FACC

Chief, Section of Pediatric Cardiology Professor of Pediatrics
The University of Chicago Children’s Hospital &
The Pritzker School of Medicine
Chicago, IL, USA

Opening of Atrial Communications Catheter Closure of Patent Ductus Arteriosus (PDA
Closure of Atrial Communications Catheter closure of ventricular septal defect
Balloon Dilation of Stenotic Valves Balloon Angioplasty
Stents Coils
Perforation of Atretic Valves  References

Over the last ten years, the cardiac catheterization laboratory has witnessed a dramatic increase in the number of therapeutic cardiac procedures, along with a decrease in the number of diagnostic ones. Moreover, the number of available (investigational or approved) devices has increased. The indications to perform therapeutic cardiac catheterization also have changed somewhat.

In this presentation, I would like to go over some of the therapeutic procedures with emphasis on the "hottest" procedures and procedures that should be abandoned. I will follow the same format given by the Council on Cardiovascular Disease in the Young, American Heart Association (1).

Opening of Atrial Communications

1. Balloon Atrial Septostomy: Rashkind and Miller first described Balloon atrial septostomy (BAS) in 1966 as a palliative procedure for transposition of the great vessels. The efficacy and safety of this procedure has been demonstrated in this patient population. However, there is a potential for development of complications arising from malpositioning of the catheter, balloon rupture or failure of balloon deflation. The currently approved septostomy catheter (MillerÔ , Baxter Healthcare Corporation, Santa Ana, CA) has a 5F shaft requiring a 6F or 7F introducer, has no end hole and has a latex balloon which may break with potential embolization of balloon fragments. Furthermore, to create an adequate sized communication the balloon has to be inflated with 3-4 cc of fluid, which may be a limiting feature in the small neonate or in the neonate with a small left atrium. The incidence of complications using this catheter ranges between 2-11%. We previously reported on a new balloon septostomy catheter (NuMED Inc., Hopkinton, NY). This catheter requires a 5 or 6F introducer, which has an advantage especially in the small neonate. This catheter also has the ability to confirm position by hand injection of contrast material or pressure measurement. These features should decrease the frequency of complications. The small size of the inflated balloon should make septostomy easier especially in the neonate with a small left atrium. Also, the fact that there is a guidewire lumen will make multiple septostomies faster by sliding the catheter over the wire, which is located in the left atrium.
So, I believe that BAS is a procedure that will stay with us for years to come.

2. Blade Atrial Septostomy: In infants older than 6-weeks and those with thick atrial septum, BAS may not be effective. Therefore, the septum has to be torn using a blade. Many cardiac catheterization laboratories are not familiar at all with this technique. Therefore, my recommendation is to perform this procedure only in labs that are familiar with the blade and perform at least one procedure per month.

3. Static Balloon Dilatation: similar to the blade technique, this procedure is performed when the septum is too thick to be torn by the dynamic BAS. This procedure is safe and will have a place in the catheterization laboratory.

Closure of Atrial Communications

In this section, secundum atrial septal defects (ASD), patent foramen ovale (PFO) and fenestrated Fontan (FF) are amenable for catheter closure using various devices (approved or investigational).

1. Buttoned device: This represents one of the oldest devices available. There is extensive experience available using this device. The technique itself is somewhat easy and simple, however, the incidence of residual shunt is high, therefore, in my opinion, the use of this device will decrease with time, unless the device is improved.

2. Angel Wings device: The device described by Das et al has been discontinued due to cardiac perforation in two patients. The perforation was thought to be due to the sharp eyelets in the corners. Therefore, unless improved, this device will not be used for humans in the USA. I believe the manufacturing company (Microvena) is working on a modified version where the eyelets are inverted inward.

3. Atrial Septal Defect occlusion System (ASDOS) device: Due to the complexity of the technique, this device won’t be available for clinical use. Although the closure rates were acceptable, the complex technique of delivery rendered its use obsolete.

4. The Amplatzer Septal Occluder: This is the most widely used device. The results of closure have been excellent. Therefore, I believe this device will be the device of choice to close ASD’s worldwide. Similarly, for PFO in patients who sustained TIA or stroke, the Amplatzer PFO device will be among the best to choose from.

5. The CardioSEAL device: this device is a modification of the old clamshell device, which was discontinued in 1991. Therefore, the problem of arm fracture and the high incidence of residual shunt will make this device less desirable than the Amplatzer for catheter closure of ASD or PFO.

6. The StarFlex: this device is a self-centering CardioSEAL (improved significantly). The early results using this device are encouraging.

In summary, for catheter closure of ASD/PFO, I believe the Amplatzer device followed by the StarFlex will be the two most commonly used devices. The former has higher complete closure rate and is more effective for larger ASD’s.

Catheter Closure of Patent Ductus Arteriosus (PDA)

PDA is a common form of congenital heart disease. The earliest report of catheter closure was in 1966. Since then, many devices have been used to achieve closure. Currently, PDA in patients beyond the neonatal period (full-term), catheter closure is the therapeutic procedure of choice.

1. Buttoned device: Again, similar to the ASD buttoned device, the problem of residual shunt is real. This device is still used by some investigators to close large PDA’s. I believe this device will be of little use in the future.

2. Botalloccluder device: This device has better closure rates, however, the size of the introducing sheath is big rendering its use in small infants and children less common. Again, this device will be of little value in the future.

3. Gianturco-Grifka Vascular Occlusion Device (GGVOD): This device is very effective in certain types of PDA’s and in aorto-pulmonary collaterals. Therefore, the use of GGVOD will remain in such conditions.

4. The Amplatzer Duct Occluder: This device is probably the most effective for moderate-large sized PDA’s. It is user friendly device. Therefore, I believe this device will be choice #1 in patients with PDA>2.5 mm in diameter.

5. Gianturco Coils: Are the most commonly used "device" for catheter closure of PDA. However, if single coils are used, the largest size PDA that can be closed effectively will be <2.5 mm. If multiple coils are used, then larger PDA’s can be closed effectively.

In summary, for small PDA’s I believe coils will be choice number 1, however, for moderate-large PDA’s, the Amplatzer device will be the first choice.

Catheter closure of ventricular septal defect

Surgical repair of multiple muscular ventricular septal defects (MVSD) is associated with considerable mortality and morbidity. Therefore, both surgeons and cardiologists will welcome the availability of a non-surgical safe approach. Over the last few years, devices designed originally for percutaneous closure of atrial septal defects or patent ductus arteriosus have been used to close MVSD’s with variable degrees of successful closure and residual shunts. Recently, the availability of the Amplatzer MVSD occluder rendered most single muscular VSD’s amenable for catheter treatment. I believe over the next few years, device closure of MVSD will become the treatment of choice. Furthermore, I believe with modification of the current device for MVSD, potentially, perimembranous VSD will become amenable for catheter closure.

Balloon Dilation of Stenotic Valves

1. Balloon Pulmonary Valvuloplasty: this was first reported by Kan et al. This procedure is considered the treatment of choice in neonates with critical PS and in any infant/child or even adult with significant gradient across the pulmonic valve. A significant gradient is defined by the presence of 50-mmHg gradient across the valve in the presence of normal cardiac output. Some investigators (including myself) accept lesser gradient (35-mmHg or more) in the presence of RVH on ECG.

2. Balloon Aortic Valvuloplasty: In neonates and young infants and children, the procedure is considered the treatment of choice in many cardiac centers. However, in some centers that lack excellent interventionalists, surgical valvotomy is preferred. I believe with improved results of the Ross procedure, aortic valvuloplasty will be limited to the neonate and young child. However, in older children and adults, aortic valvuloplasty should be probably abandoned.

3. Mitral valvuloplasty: this procedure will be limited to patients with acquired "rheumatic" stenosis. However, it should be abandoned for congenital mitral valve stenosis.

Balloon Angioplasty

1. Balloon Angioplasty of Coarctation: Since its introduction in the early 1980’s, balloon angioplasty has become an accepted modality of treatment for recurrent coarctation of the aorta. However, balloon angioplasty for native coarctation of the aorta remains a controversial issue. There are few reports of acute and long-term outcome of balloon angioplasty of native coarctation of the aorta. I believe that in infants beyond the age of one month, with discrete coarctation of the aorta, in the presence of an active interventional program, balloon angioplasty should be the treatment of choice. However, in smaller neonates especially if the PDA is still open, or if the coarcted segment is long, balloon angioplasty should be abandoned. In contrast, for recurrent or residual coarctation, the treatment of choice is balloon angioplasty.

2. Branch Pulmonary Artery Stenosis: Branch pulmonary artery stenosis (BPAS) is defined as a single narrowing or multiple constrictions that can be localized or diffuse located at, or distal to the origin of the primary branches of the pulmonary artery. This lesion is associated with the Alagille and Williams syndromes and congenital rubella infection . It occurs in 30% of patients with tetralogy of Fallot and can develop after the placement of systemic to pulmonary shunts or after the arterial switch operation. This lesion can increase the morbidity and mortality associated with corrective surgery for congenital heart disease. Nonsurgical techniques available to treat BPAS include intravascular stent implantation or balloon angioplasty with low or high pressure balloon catheters. Balloon angioplasty relieves stenosis by tearing the intima and a portion of the media and allowing scar tissue to support the dilated vessel walls. The placement of an expandable intravascular stent provides further support to a balloon dilated vascular wall and prevents recoil to the vessel’s original diameter. However, long-term studies are lacking to address the potential for stent re-expansion, . The early experience with high pressure balloon (HPB) angioplasty (up to 20 atmosphere) has demonstrated a success rate of 72% and a complication rate of 13%. The use of HPB angioplasty successfully dilated almost 50% of the lesions that were refractory to low pressure balloons. I believe that in smaller infants and children, the primary treatment of choice for BPAS should be balloon angioplasty.

3. Systemic Venous and Pulmonary Venous Stenosis: The success rates for balloon dilatation of such obstructions is less than for other conditions. I believe for pulmonary venous obstruction, balloon dilatation should be abandoned. If the child is big, an attempt at stent implantation is probably worthwhile. However, for systemic venous obstruction, the success rate is higher and balloon angioplasty should be attempted first.

4. Balloon Angioplasty of Systemic-to-Pulmonary Shunts: if the stenosis is discrete, the procedure is effective and should be the first modality of treatment, however, if the stenosis is long, the procedure should not be performed.

Stents

The availability of stents to treat congenital heart disease revolutionized our approach and thinking in managing certain types of CHD. Lesions that were not amenable for the interventionalists and were considered surgical disease now have become in the arena of the cardiologists.

1. Branch Pulmonary Artery Stenosis (BPAS): as mentioned above, this lesion benefited the most from the availability of stents. Surgical management of this condition has at best 50% success rate; balloon angioplasty using high pressure balloons has a success rate in the range of 60-70%; therefore, stents were used initially in this condition with excellent results. Some investigators believe that stent implantation should be the primary procedure for BPAS (their reasoning is that loss of vascular access could result from balloon angioplasty). I believe with advancement in technology and miniaturization of equipment, stent implantation will become the procedure of choice in management of this difficult condition.

2. Coarctation of The Aorta: Native coarctation of the aorta in older children (weight >25-30 kg) and adults should be treated by stent implantation. The limiting factor for the use of stents is the vascular access. Currently, I use the front-loading technique to deploy stents. Therefore, I’m able to introduce stents using 9-Fr sheath (irrespective of the size of the stent or balloon). Similar to BPAS, this will become the treatment of choice in the near future.

3. Systemic Venous Obstruction: Stent implantation will be the choice of treatment in such conditions. Balloon angioplasty is effective in some cases, therefore, for a predictable result, stent implantation is the treatment of choice.

The use of covered stents will witness an increase in its use. I believe within the next few years, covered stents will be used to complete a lateral tunnel (after the patient underwent bi-directional Glenn anastomosis), in the management of PDA associated with coarctation of the aorta and in cases of aortic dissection after balloon angioplasty.

Coils

The use of coils to embolize collaterals or PDA has increased significantly over the last few years.

1. Coil Closure of PDA: as mentioned above, coils have become the treatment of choice for small-moderate sized PDA. I believe if the PDA is <2 mm, the use of coils will be very cost-effective. However, if the PDA is large (>2.5 mm), [unless the interventionalist is very aggressive] in deploying multiple coils, the use here won’t be effective and probably the procedure should be abandoned.

2. Aorto-pulmonary Collaterals: coil embolization should be the first line of treatment, unless the collateral is rather large, then other devices should be used. This procedure will be with us for many years to come.

3. Surgical Shunts: the use of coils is effective in such cases. Due to the acute angles of the take-off of surgical shunts, the introduction of a large delivery sheath for deployment of devices will be difficult, therefore, coil embolization using 4-Fr sheath and catheter will be easier.

4. Coronary Arteriovenous Fistula: for most fistulas, coil embolization should be the treatment of choice. The procedure is safe and effective.

5. Pulmonary Arteriovenous Fistulas: coil embolization should be the treatment of choice. If the fistula is large, devices can be used instead.

6. Venovenous Collaterals: similar to aorto-pulmonary collaterals, these could be closed using coils. They are present in patients after bi-directional Glenn anastomosis or after Fontan operation.

Perforation of Atretic Valves

In some patients with pulmonary atresia/intact ventricular septum with good RV size, perforation of the atretic valve using radiofrequency/laser or the stiff end of a wire would replace open heart surgery. Such patients may remain cyanotic post perforation, therefore, shunt placement may also be needed, but this could be done off bypass.

So, in summary, there are many interventional procedures available for us to treat a wide spectrum of congenital heart malformation. Fortunately, technology is improving, therefore, I believe, over the next 5 years some devices will become the standard of care for ASD/PFO/PDA closure, some procedures (stent implantation) will witness a significant increase in the indications. Some procedures (stent for pulmonary vein stenosis/balloon valvuloplasty for congenital mitral stenosis/some devices) should probably be abandoned.

 

Figures

1. PDA pre and post closure using multiple coils.

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2. PDA pre and post closure using GGVOD

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3. Coronary arteriovenus fistula pre and post coit closure

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4. Native Coartitation angioplasty (pre and post)

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5. A patient with bilateral branch pilmonary artery stenosis following the arterial switch operation treated successfully with stents

figure5a.jpg (4030 bytes)  figure5d.jpg (3159 bytes)

figure5b.jpg (3637 bytes)   figure5c.jpg (3354 bytes)

 

 References

1. Allen HD, Beekman RH, III, Garson A, Hijazi ZM, Mullins C, O’Laughlin MP, Taubert KA. Pediatric therapeutic cardiac catheterization. A statement for healthcare professionals from the Council on Cardiovascular Disease in the Young, American Heart Association. Circulation 1998;97:609-25

Ziyad M. Hijazi, M.D., FACC
The University of Chicago Children’s Hospital &
The Pritzker School of Medicine
Chicago, IL
E-mail: zhijazi@peds.bsd.uchicago.edu

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Update
10/01/99