Page 19 - Journal of Structural Heart Disease Volume 4, Issue 5

Original Scientific Article
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teriosus, atrial septal defect), the fistula can be closed at the time of repair of the primary cardiac lesion.
Transcatheter Closure Techniques
Once a decision is made about the need for closure of the fistula, it is very important to plan the proce- dure appropriately. We recommend the following:
1. Discussion of the case with an interventional adult
cardiologist colleague. We can’t overemphasize the importance of collaboration with adult cardi- ologists when it comes to the coronary circulation. They need to be involved in the planning of the case.
2. Discussion of the case with an interventional ra- diologist to see what equipment may be needed. Interventional radiology uses many coils and cath- eters that are not readily available in the congenital cardiac catheterization laboratory. We have found over the years that getting help from intervention- al radiology has contributed to the success of the procedures.
3. If the patient is an adult age (over 18-21 years), we advise to admit the patient post-procedure into an adult unit equipped with continuous cardiac moni- toring (telemetry) and with staff familiar with EKG’s and management of cardiac ischemia. We believe this is an important aspect of managing such pa- tients. The pediatric units, for the most part, are not familiar with cardiac ischemia/enzymes, and they may miss important events in these patients that could lead to catastrophe.
4. When placing coils/devices to occlude fistulae, it is very important to delineate the myocardial branches to ensure that coils/devices are beyond the last viable myocardial branch. Obviously, oc- clusion proximal to such branches will result in car- diac ischemia.
5. Available coils: coils are made of different materi- als, available in various lengths, diameters, shapes and several methods of delivery. Coils are available in lengths from 1 to 300 mm and in diameters rang- ing from 1 to 27 mm. Available coil shapes include J- or C-shaped, helical, conical, tornado, straight, and complex three dimensional (3D) shapes. Coils may be bare or fibered with material such as Da- cron, nylon fibers, polyester, wool, silk, or polyvinyl
acetate (PVA) embedded within them to increase thrombogenicity. Steel was the initial material used for coils then came Platinum and different alloys that made them softer, more radio-opaque and non-ferromagnetic enabling future MRI follow-ups [14]. The methods of coil delivery had evolved over the last five decades in response to the need for a safer and more controllable deployment as well as to solve the technical problems encountered in old methods. Among the early methods were the pushable, injectable and liquid coils delivered by pushing wires or injecting saline or contrast after loading the coils in the delivery catheters [14]. The first detachable coil was described in 1977. Cur- rent detachable coils are deployed by a variety of mechanisms including mechanical, by electrolysis, and by hydrostatic means. The disadvantage of the mechanical detachment is that there is often friction between the coil and the microcatheter, during embolization through tortuous vessels, this friction can limit delivery, or the coil can rotate or flip at detachment [14]. Deployment of coils can be done by a wide range of catheters, the current assortment of microcatheters widely used may not be all well suited for several anatomic variants, including excessive vascular tortuosity. The most commonly used microcatheters for coiling are Ex- celsior SL-10 and 10-18 (Stryker, Kalamazoo, MI, USA), Echelon 10 and 14 (Medtronic, Minneapolis, MN, USA) and Headway 17 (Microvention TERUMO, Tustin, CA, USA). As mentioned above, these cathe- ters are readily available in radiology departments engaged in aneurysm coiling. The proper coil for embolization should be sized 20 to 30% larger than what the target vessel measures on pre-deploy- ment angiogram to prevent distal embolization or migration. Placement of an undersized coil risks its distal embolization away from the intended lo- cation. Attempting to place an oversized coil may result in the coil not forming the intended shape or even straightening in the vessel [14]. In general, dense packing of the target vessel is recommend- ed to achieve complete embolization. The key to inducing complete thrombosis is cross-sectional occlusion which can be done by different tech- niques [15]. A scaffold technique involves initially deploying a higher radial force coil followed by a
Journal of Structural Heart Disease, October 2018
Volume 4, Issue 5:212-221