I have been performing interventional cardiology
for nearly 30 years.

Procedures - What will Happen?

 

I have widespread clinical and research interests in interventional cardiology, and have undertaken a very large number of cardiac procedures in each of these clinical areas whilst at Papworth Hospital in Cambridge.

 

Before the procedure you will be prepared and asked to don a flimsy gown and paper underwear. What will happen is explained in detail. You will be asked to sign a consent form which gives us permission to do the tests and acknowledges that you have understood the risks (see below). The nurses will shave a small amount of hair from the groin area so it does not interfere with the equipment. Often you will be able to walk to the theatre. I perform these procedures in a modified operating theatre, called a cardiac catheterisation laboratory (usually known as a cath lab). This is a sterile area where you will be draped in sterile green or blue paper sheets, and staff are clothed in sterile gowns. Caps and masks are not always worn. The difference from a normal operating theatre is the presence of a large X-ray machine. This is a very high resolution machine allowing real time video images of the passage of devices into the circulation and the heart, and the taking detailed images. The images are usually made with an injection down the catheter (long plastic tube). The dose of radiation is surprisingly small. To see the outline of the arteries, a contrast medium or dye is used which is easily seen on Xray. This occasionally may induce a warm flush or rarely chest pain. In the past, the dye often made the patient rather sick, and allergic reactions were common, but the newer and much more expensive products are much less troublesome.

 

I perform most of the procedures via the femoral vessels (these are an artery and vein at the crease at the top of the leg in the groin). These vessels are entered by needle puncture after the placement of copious amounts of local anaesthetic. This is usually almost completely painless. The passage of catheters (long specially designed plastic tubes) takes place through the blood vessels themselves. Fortunately, us human beings have no pain sensation inside blood vessels - so other than a curious sensation of pressure, normally nothing is felt. Many patients feel anxious before and during these procedures, which is not surprising but many are relieved by the absence of pain and reassurance from experienced staff. We give some patients a gentle sedative to calm their fears. The passage of the catheters, which are specially shaped for this particular purpose , is viewed on the Xray screens and are directed to wherever required both by rotation and forward and backward motions. The movements of the catheters on the Xray screens as well as the images taken can be seen by the patients (although some people definitely don't want to look!). Many comment how extraordinarily strange it is to see things moving inside you without any sensation of it happening. The tubes placed in the arteries have valves attached to prevent bleeding.

 

figure coronary angiogram, normal right coronary artery, note the catheter in the artery and the smooth appearance of the vessel.

 

At the end of the procedures, the tubes need to be removed. As they are placed in blood vessels, there is a risk of bleeding. To prevent this, simple pressure with the fingers may be sufficient - plus there are a number of gadgets to help the process. There are also some clever devices which introduce a plug (of collagen) or a stitch into the artery to seal the hole. Most patients need a few hours of bed rest. For simple or painless procedures such as a coronary angiography, PCI and defect closure, many go home the same day. Although the area in the groin may be a little sore for a few days there should be no other significant pain.

 

For procedures such as a hole in the heart (PFO and ASD) closure (see below for description) an extra form of imaging is used, namely ultrasound. This is done in one of two ways. The first option when using a general anaesthetic involves the use of a TOE probe. This is like an endoscope and is placed in the oesophagus (gullet) , which fortunately lies just behind the heart and produces excellent images particularly of the back portion where the holes in the heart are found. This probe is passed under a general anaesthetic which is used for ASD closure. An alternative ultrasound probe is available which is much smaller and is passed through the veins to the heart (known as intracardiac echo or ICE). This can readily be performed under local anaesthetic and is painless.

 

This is an echo picture taken in the cath lab showing a coloured jet passing across a small hole in the heart from the left atrium above to the right atrium below.

 

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