CONTROVERSIES IN CARDIOLOGY
Year : 2004 | Volume
: 5 | Issue : 2 | Page : 39--43
Catheter delivered devices are not preferred over surgery for management of secundum ASD
Richard A Jonas
Chief, Cardiovascular Surgery, Children's National Medical Center, Washington DC, USA
Richard A Jonas
Children�SQ�s National Medical Center, 111 Michigan Avenue, NW, Washington DC 20010
|How to cite this article:|
Jonas RA. Catheter delivered devices are not preferred over surgery for management of secundum ASD.Heart Views 2004;5:39-43
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Jonas RA. Catheter delivered devices are not preferred over surgery for management of secundum ASD. Heart Views [serial online] 2004 [cited 2023 Nov 29 ];5:39-43
Available from: https://www.heartviews.org/text.asp?2004/5/2/39/64560
General Principles in the Management of Congenital Heart Malformations
There are several fundamental principles in the management of congenital malformations of the heart that are generally agreed upon. Wherever possible, growth potential should be incorporated. Synthetic material should be avoided if an autologous tissue alternative is available and if there is no autologous tissue, at least biological tissue should be employed. Finally, it is now generally accepted that repair should be performed early in both a physiological and anatomical sense whenever possible. Only in this way can the secondary deleterious effects of the congenital heart anomaly be minimized.
Advantages of Surgery for Closure of a Secundum ASD
Present day surgical methods for closure of the secundum ASD follow the general principles of congenital heart management.  No synthetic material is required other than a single prolene suture, which is used either to appose the edges of a smaller secundum defect directly or to secure an autologous pericardial patch in the case of a larger defect. Many large series have documented that closure is essentially 100% complete.  The incidence of important complications such as bacterial endocarditis, early or late thromboembolism and early or late life threatening hemorrhage is exceedingly low. Pericardial tamponade has been reported  but can be minimized or eliminated by the creation of a pleuro-pericardial window at the time of surgery. (unpublished data, Children's Hospital Boston) [Figure 1].
Disadvantages of Surgery for Secundum ASD
The disadvantages of surgery that are often cited by those promoting interventional catheter closure are today very much less than they were in the past. The pain associated with surgery is quite transient when the procedure is undertaken early in life, for example by 2 years of age  . One only needs to witness the toddler up and running around 24 hours after surgery to realize that the cartilage and ligaments of early childhood are extremely flexible. Furthermore, the midline partial sternotomy incision requires division of no muscle. The incision takes advantage of the normal hinging of the ribs on the spine as for usual respiratory excursion.
Deleterious effects of cardiopulmonary bypass are often cited as an important disadvantage of surgery. However, intensive research efforts by many groups including the author's have now minimized the impact of cardiopulmonary bypass on intellectual development. One of the most important realizations has been that hemodilution was frequently extended to an unsafe degree in the child undergoing closure of a secundum ASD as was the case in a study reported by Visconti et al  . In Visconti's study which showed a worse developmental outcome with surgery relative to device closure, patients underwent procedures in the early 90's when hematocrit was allowed to fall as low as 13%. A recent prospective randomized clinical trial undertaken by the author in infants undergoing more complex procedures demonstrated that there was a measurable improvement in developmental outcome with a hematocrit of 27% versus even 21%  . Currently that trial is ongoing with patients being randomized between 35% and 25%. Previous trials had demonstrated important advantages of the pH stat strategy relative to the alpha stat strategy , as well as the disadvantages of long periods of hypothermic circulatory arrest, which should certainly not be necessary for a simple secundum ASD closure  . In fact cardiopulmonary bypass for secundum ASD closure is brief, the degree of hypothermia is mild and the cross clamp time is frequently less than 10 minutes. Furthermore, the need for minimal hemodilution in the current era does not necessarily necessitate increased exposure to transfused blood. In our prospective randomized trial there was no difference in exposure to blood products with the use of a hematocrit of 27% versus 21%. This was achieved through aggressive use of conventional ultrafiltration as well as minimizing of priming volume using new reduced prime circuits.
A third disadvantage of surgery is the cosmetic disadvantage of a midline skin incision. However with modern minimally invasive techniques a scar can be as short as 3.5 to 4 cm and can be positioned at the lower end of the sternum where it is rarely visible with conventional clothing including bathing suits.
Why device closure is inferior to surgery
Although catheter delivered device closure of a secundum ASD provides a superior cosmetic result and results in less transient pain as well as complete avoidance of cardiopulmonary bypass, nevertheless there are a large number of very important risks, many of them catastrophic in nature, that are often overlooked when considering which approach is to be used. These risks can be considered under the categories of general risks, technical risks and specific risks of individual ASD devices. Currently the incidence of these risks remains poorly defined.
General risks of device closure [Table 1]
It is often overlooked that device closure today is almost always performed under general anesthesia so that there is no reduction in risk in this regard relative to a surgical approach  . In addition, device closure is still usually performed in the catheterization laboratory and involves radiation exposure. Blood loss is not trivial and quite often requires exposure to blood products. It is very common for children to be febrile following cardiac catheterization and undoubtedly introduction of sheaths and catheters through the groin, particularly if the procedure is prolonged, carries a risk of blood stream sepsis, which may result in seeding of the prosthetic device.
Technical risks of device closure [Table 2]
There are a number of technical risks that the patient is exposed to in undergoing catheter delivered device closure of a secundum ASD. While some of these risks are probably decreased with operator and team experience there are some risks that are dependent on complex and delicate hardware integrity. For example, delivery catheter malfunction can result in premature release of a device and subsequent device embolization. Alternatively there may be failure of a device to release, which can result in the need for surgery to remove the device through the femoral vessels. Injury to the femoral vein can occur secondary to the introduction of the relatively large sheath that is required. The sheath or catheter can cause perforation of the heart at the time of device placement. Cardiac perforation with subsequent fatal tamponade has been reported secondary to injury of the pulmonary veins by the sizing balloon catheter when this is employed prior to device closure. Fatal neurological injury has been reported because of massive air embolism occurring through the sheath. Thromboembolism causing stroke has also been reported and can occur from fibrin buildup either on the sheath or catheter as well as on the device itself.
Specific risks of ASD devices [Table 3]
Current devices are constructed from metal such as nitinol (containing nickel) or stainless steel. In addition, the devices incorporate fabric to induce initial thrombosis within the interstices of the fabric with subsequent fibrous in-growth in much the same way that vascular tube graft prostheses function. An important difference relative to tube graft prostheses or the very small Dacron patches that are often used for VSD closure is that the metal that is employed to hold the fabric in place carries a risk of slow perforation through the heart muscle with the repeated contraction of the heart over months or years. Late cardiac perforation has been seen with increasing frequency and can lead to a catastrophic failure mode of these devices as has been documented by the FDA through its MAUDE database. Other important complications that are documented on the MAUDE database are infection of the prosthesis necessitating removal, late embolism of infected fibrinous material, thromboembolism and stroke with a consequent need for long term coumadin anticoagulation, device failure with fracture of the stainless steel arms of certain devices  as well as a possible risk of late nickel allergy .
A survey of members of the Congenital Heart Surgeons Society documented that a number of surgeons have been called upon to deal with serious late complications of catheter-implanted devices. Interestingly, a computerized search of the National Library of Medicine for published reports of such events results in no reports identified. Fortunately however, the FDA has established its MAUDE database in which centers implanting ASD devices are required to report complications. The MAUDE database can be accessed by going to www.fda.gov, clicking on "medical devices" in the left-hand column, then clicking on "medical device reporting (MDR)" on the next screen, also in the left hand column and then on the next screen clicking on "MAUDE" in the right hand column. On the next screen specific devices should be searched such as "amplatzer" or "cardioseal".
Examples of complication reports regarding ASD devices on the FDA database
Late ASD recurrence
Although it is well known that there is an important risk of early residual ASD related to failure of a device to seat perfectly, the author was unaware until viewing the MAUDE database recently that there is a risk of late recurrence of secundum ASD following device closure. In a report dated 9/4/03 a patient was found to have a recurrence of a secundum ASD which became apparent more than one year following implant after documented complete closure. The device had apparently "drifted to the right atrium". The patient became symptomatic and required surgical removal of the device.
In another report dated 4/18/00 a patient who had previously had a starflex implant which was well positioned at the time of hospital discharge developed fever, stomach pain and bleeding per rectum following a session of swimming and diving. The device was located in the aorta. The patient was taken to the cath lab for device removal but unfortunately the device became lodged in the femoral vein requiring surgical cutdown and venous repair. Nevertheless the patient recovered from these events.
Cardiac Arrest, Tamponade, Neurological Injury
In a report dated 11/13/03 a patient who has received an 18 mm ASD implant went into cardiac arrest 1 1/2 hours following the procedure. The patient was found to have pericardial tamponade and during emergency thoracotomy was found to have multiple tears in the left atrial wall. The patient suffered neurological injury consequent to the arrest and resuscitation.
Death, massive air embolus
In a report dated 1/23/02 as the sheath/dilator assembly was advanced into the left atrium, a large amount of air entered the heart causing massive air embolism with subsequent introduction into the coronary and cerebral circulation. Although the patient was successfully defibrillated after 24 shocks, the patient subsequently died three hours later in the intensive care unit.
In a report dated 6/5/03 a patient who had been previously feeling well 24 hours after hospital discharge was sitting doing homework when the patient began to complain of chest discomfort and difficulty breathing. While being helped to the car the patient collapsed and was subsequently found by EMTs 10 minutes later to be pulseless and unresponsive. At autopsy fresh blood was found in the pericardial space and left pleural space.
In another case of pericardial tamponade dated 3/18/03, a 36 mm device was placed. Four hours postoperatively the patient developed a profound low output state. Despite resuscitative efforts, the patient died. At autopsy 500 ml of blood was found in the pericardial space and 200 ml in the pleural space. A perforation was found in the right upper pulmonary vein, which was thought to be due to either manipulation of the sizing balloon or the 12 French delivery sheath.
In another report dated 4/20/02 a patient was discharged from hospital following uneventful device implantation. The patient suddenly collapsed 72 hours after the procedure in a parking lot. The patient briefly regained consciousness but shortly after arrival in the emergency room lost consciousness and was pulseless with a slow heart rate. At autopsy two small holes were found, one in the lateral aspect of the aorta above the aortic valve and another adjacent to this on the left atrium.
Gatekeeper role of the cardiologist for surgical referrals
The traditional management of patients with congenital heart disease has involved judgment by the referral cardiologists regarding the results achieved by surgical colleagues. The risks involved in having a self-referral and self-assessment system as occurs with catheter delivered devices are self-evident. Interestingly, the new Stark legislation regarding self-referral by physicians has recently come into effect but is probably not applicable to cardiology self-referral. Nevertheless it is difficult to know who will be in a position to critique the results of catheter delivered devices where surgeons remain dependent on cardiologists for patient referrals. There is a real risk that the surgeon who speaks out will suffer political consequences for not being "supportive" of his cardiology colleagues.
The author feels confident that it should be possible to develop catheter delivered mechanisms of atrial septal defect closure that will fulfill the general principles of congenital heart management enunciated in the introduction to this article. However, until catheter closure incorporates autologous tissue and avoids rigid prosthetic material and until risks are better defined, surgery should remain the procedure of choice for elective closure of both small and large secundum ASDs.[Figure 2],[Figure 3]
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