Today’s video is on the subject of intracoronary stents. In this video, I will talk about what stents are, why they are used and what benefits and risks are associated with their implantation.
The first thing to understand is that for most of us, as we get older, the major risk to our health will be progressive ‘wear and tear’ in our heart arteries (coronary arteries). There are 2 problems with this process. The first is that as the ‘wear and tear’ progresses, there will be progressive narrowing of parts of the heart arteries which then means that it becomes more difficult for the blood to get to where it is needed especially at times of increased demand and therefore the muscle cells which need the increased amount of blood would suffocate and thereby manifest with symptoms of chest discomfort or breathlessness. This is called stable angina.
The second problem with ‘wear and tear’ is that the vessel becomes more prone to blood clots forming acutely within the blood vessel and very suddenly a blood clot can block the vessel causing acute suffocation of the heart muscle. This is called unstable angina or a heart attack.
In the old days, the only way to treat angina was either using medications or open heart surgery. Whilst medications were able to reduce the demand of the heart or transiently open these blood vessels thereby relieving symptoms they did not really fix the narrowing.
Surgery on the other hand was a major undertaking with the need to cut the chest open under a general anaesthetic. The surgeon would then have to take another blood vessel from the leg to attach onto either side of the narrowed blood vessel to bypass the narrowing. Not every patient was fit enough to undergo surgery and there was a limitation in that the narrowing had to be in a vessel big enough for the surgeon to be able to stitch the bypass onto.
GIven these limitations, scientists became increasingly interested in seeing if there was a way of accessing the narrowed blood vessels without the need for open heart surgery. The breakthrough came in 1953 when a Swedish radiologist, Dr Sven Ivar Seldinger developed the Seldinger technique which made it possible to access internal blood vessels by puncturing a blood vessel which was externally visible. The idea was that if one could puncture an artery in the wrist or the groin then you could introduce a thin wire through the needle and then use xray guidance to move it all the way up to the heart and then cannulate the coronary arteries. If you could then slide a tube up the wire and remove the wire, you could inject radiopaque dye into the blood vessels and take xrays and identify the location of the narrowings. That procedure was called angiography.