SACHIN KHAMBADKONE
MBBS DCH DNB MRCP MD CCT
LONDON PAEDIATRIC CARDIOLOGY
The Portland Hospital London
Great Ormond Street Hospital London
INTERVENTIONAL CATHETERISATION
What is cardiac catheterisation?
Dr Khambadkone specialises in cardiac catheterization and interventional cardiology. Cardiac catheterisation is a very specialised procedure in which a long and flexible tube called a cardiac catheter is inserted into a vein or artery in the groin, limbs or the neck to achieve access to the heart chambers, large arteries and veins close to the heart. Interventional or therapeutic catheterization involves treatment of cardiac conditions using catheter techniques. They always include a diagnostic assessment before and after the interventional procedure, but under the same anaesthetic. These procedures are used to open severely narrowed valves or arteries or veins (balloon valvotomy / balloon or stent angioplasty), closing holes in the heart with devices (atrial septal defect, ventricular septal defect , patent ductus arteriosus) and heart valve replacement or implantation with catheter rather than open heart surgery. Dr Khambadkone is an expert in the field of performing interventional catheterization on babies, infants and young persons.
Are there any risks?
As with any procedures on the heart, there are risks related to interventional procedures. All cases are discussed at a multidisciplinary meeting before undertaking such procedures. Risks of procedures relate more often to the underlying cardiac condition as much as the procedure itself. The risk of most procedures far outweigh the short and long term benefits of the procedure. Risk of emergency surgery, brain damage, other organ damage or death are rare in most interventional cardiology procedures.
What does the procedure involve?
Dr Khambadkone performs these procedures in a Cardiac Catheterisation Laboratory. The team involved in catheterization include a cardiac anaesthetist, specialist nurses, a physiologist - expert in monitoring the baby during the procedure and specialist radiographers helping with acquiring images.
The child lies on a specially designed table with two large cameras that take a video of X-rays as Dr Khambadkone will guide the catheter into the veins and arteries to the heart and its various chambers. The radiation exposure is meticulously controlled and monitored by Dr Khambadkone and the radiologist. With the help of the physiologist, the pressure and oxygen saturations are measured in the chambers of the heart, and in the arteries and veins connected to them.
As a standard protocol, all children having cardiac catheterization would be given Heparin, a blood thinning agent to prevent clot formation in the circulation when catheters are inserted. This is closely monitored both to maintain adequate blood thinning (anticoagulation) but also to avoid excessive anticoagulation which may increase the risk of bleeding.
What is cardiac angiography?
Angiography involves injection of a dye (radio-opaque contrast) at a rapid rate into the circulation. This mixes with the blood and highlights its flow through the heart chambers, arteries and veins. The dye can highlight holes in the heart, narrowing or leaking of heart valves, narrowing of arteries and veins or missing parts of the heart chambers, arteries or veins. After the procedure, firm pressure is applied to the site of entry through the artery or vein to stop bleeding. Rarely, this may re-start after children wake up distressed after the anaesthetic or if they cough or cry incessantly. Bruising or haematoma formation (a collection of blood or clot in tissue space) is seen occasionally but they resolve completely over time.
What is the care post procedure?
Most interventional catheterizations are performed as day cases. Certain complex procedures would require to stay in the hospital for one night. During recovery, children are monitored for any residual effects of anaesthesia as well as potential problems related to catheterization. Depending upon the procedure and the underlying condition, they may need to be on bedrest the site of entry is healed well. Once fully recovered, they are reviewed and discharged. There are no stitches involved in majority of cases and a dressing over the area of the skin entry site can be removed at discharge or the next day. Dr Khambadkone will offer clear follow-up instructions to all the patients at discharge. Follow-up appointments are usually required within a few weeks. Echocardiogram is performed when indicated.
EXPERTISE
BALLOON VALVOTOMY
Balloon valvotomy procedure uses a balloon catheter (special tube with a balloon at the end of it) to stretch a narrow valve in the heart. This is one of the commonest procedures performed in babies, infants, children or young adults. It works by “splitting” the flaps (leaflets) of the valve that get stuck together causing a narrow opening. The balloon is stretched across the valve only during the procedure and then removed and does not stay in the body. Although the abnormally formed valve remains in the heart, its function improves significantly. The procedure has a high success rate in heart valves on normal or slightly smaller size, but with stuck leaflets. It is not often as successful in small heart valves. After balloon valvotomy, although the valve opens better, it starts leaking blood back into the heart chamber and this is tolerated quite well. Close monitoring of the valve function is mandatory and sometimes the procedure may need to be repeated.
BALLOON ANGIOPLASTY
This procedure works by stretching narrow (stenotic) arteries or veins. A balloon catheter is used to stretch the narrow part of the artery or vein under some pressure, to open it up. Based on the underlying problem, the long term success of the procedure varies. In growing children, despite a successful procedure, balloon angioplasty may need to be performed again to catch up with growth of the child.
STENT ANGIOPLASTY
The use of stents (slotted metal tubes) to provide an internal scaffolding of support to narrowings in the heart or blood vessels is called stent angioplasty. This technique is successful when the narrowing can be improved with a balloon catheter but does not stay open once the balloon is removed. The stent remains inside the body across the narrowing and holds it open. Although very effective they do not grow in children and a balloon procedure of the stent may need to be repeated. Stents could become narrow with ingrowth of tissue or clots within them and may need to be stretched again. They can fracture from repeated movements within the circulation (stent fractures) and require additional stents within the old ones ( stent-in-stent).
DEVICE CLOSURE
Holes in the heart (Atrial septal defect and ventricular septal defect) or outside the heart (Patent ductus arteriosus or PDA) can be closed with interventional catheterization. Dr Khambadkone performs these procedures in children and young adults. A device, called an occluder, is used to close holes in and outside the heart. These are made from a special alloy called Nitinol that allows the occluder to retain its shape and size once delivered into the heart through a small catheter. The devices are attached to a delivery cable that can be unscrewed once I am happy with the device size and its position in the hole. The devices hold in place with friction contact, and hence, using an appropriate sized device is crucial to avoid it moving out of position. Once held in place for a few hours ( PDA device) or overnight (ASD and VSD devices), they are usually secure and would not fall out with normal activities. The devices promote closure of the holes with their physical presence and formation of a clost within them to stop flow. This may take anything between a few hours to a few days depending upon various factors. For devices within the heart, patients are prescribed a medication (low dose Aspirin) to reduce clot formation, for a period of 6 months, following which the inner layers of the heart start growing over the device and the risk of clot formation reduces significantly. The devices don’t need to be changed with growth and the heart grows around it. Long term outcome of device closure of holes is very good.
PERCUTANEOUS PULMONARY VALVE IMPLANTATION
This procedure uses cardiac catheterization to implant valves in the heart. Dr Khambadkone has been at the forefront of introducing this technique in Cardiology and was one of the first to implant heart valves and help set up these procedures in different parts of the world. The procedure involves inserting large tubes in to the circulation that allow delivery of heart valves that are mounted inside a large stent. The valves could be natural (made from veins of bulls or cows) or man-made (valve leaflets cut out from a layer covering mammalian hearts in horses or pigs) and are stitched inside the stents that are then delivered to the desired site in the heart. The use of this technique has brought out a remarkable advance in treating congenital heart disease by reducing the life time burden of heart valve surgery in many conditions. This technique does not work in all patients and initial investigations are required to assess whether it is feasible. The procedure is slightly longer than other interventional procedures and require the patients to stay in the hospital for one night. Recovery is quite quick and patients can get back to their daily activities within a couple of days. The catheter valves are as good as valves implanted by surgery, although no valve is perfect and these are more prone to infections and don’t last for a life time or grow with a patient. Also, this technique can be used to implant valves within previously implanted catheter or surgical valves.