Balloons are used on a daily basis in the paediatric and congenital heart catheterization laboratory. A wide range of balloons is currently available. Most balloons are used for static dilation of a cardiac or vascular structure. The properties of those balloons vary, and the differences have to be known and understood by the interventionalist in order to make the best use of them. Pressure characteristics are of major clinical importance. Low-pressure, medium-pressure, high-pressure and ultra-high-pressure balloon catheters exist and have different clinical applications. The cutting balloon, the BIB® catheter and the dumbbell-shaped balloons may be very useful for dilation in specific circumstances. Balloon catheters may be used for atrial septostomy and for sizing of heart defects. Balloon catheters need careful preparation, introduction and inflation. Complications may occur and need to be correctly recognized and managed.
KeywordsStatic balloon dilation Pressure Septostomy Sizing balloon Cutting balloon
Preparation of balloons. Step 1: Fill 1 syringe and an indeflator with diluted contrast. The recommended ratio is 1 unit of contrast and 3–4 units of saline, but this may vary according to the type of balloon used, the purpose and operator’s habits. The size of the syringe depends on the size of the balloon. A second syringe can replace the indeflator, if the indeflator is not needed (low pressure balloons). Step 2: Connect the indeflator and syringe to a three-way stopcock. Deair the whole system (syringe, indeflator and stopcock) before connecting to the balloon. Step 3: Deair the balloon. This can be done in different ways. The balloon can be gently inflated at no pressure which will allow subsequent removal of the air bubbles. However, this technique has the disadvantage of unfolding the balloon, which will then loose its ‘profile’. Refolding the balloon is sometimes possible but time-consuming. The usual way of deairing is the ‘negative prep’ technique: a strong negative pressure is applied to the balloon with the indeflator or with the syringe, and this negative pressure is maintained by blocking the indeflator or syringe . The three-way stopcock is then turned to connect the balloon with the other syringe which will then allow the balloon catheter to passively fill with the contrast. This manoeuvre is repeated a few times to allow full replacement of air by contrast. At the end, negative pressure is again applied to the balloon before entering the balloon catheter into the sheath. Step 4: Flush the wire lumen of the balloon catheter (M4V 16073 kb)
Balloon inflation and deflation with indeflator. When using an indeflator for balloon dilation, two steps have to be distinguished. During the first step, the indeflator needs to be in the ‘open’ position. Pushing gently on the piston pushes the diluted contrast into the balloon at low pressure. Once the balloon has reached the full diameter, leaving only the waist at smaller diameter, the indeflator has to be switched to the ‘closed’ position. The piston of the indeflator then needs to be screwed to increase the pressure gradually. Once the waist has disappeared, the indeflator has to be switched again to the ‘open’ position to release the pressure and withdraw the diluted contrast (M4V 21664 kb)
Burst of balloon. This video shows the longitudinal tear of a Tyshak II® 25 mm balloon used to try to replace and dilate unstable stents placed in a very dilated pulmonary valve, before percutaneous valve insertion. The contrast suddenly disappears into the pulmonary arteries which signs the rupture of the balloon (AVI 100773 kb)
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