Tuesday, May 09, 2006

Lessons from the Beijing and Seoul PCI Meetings

When we are invited to overseas meetings, we also take the opportunity to compare our standard of practice and approach to PCI (percutaneous coronary intervention), with the leading institutions in Asia. In the recent trips to Beijing and Korea, it was obvious that their widespread usage of intravascular ultrasound (IVUS) with the virtual histology mode has given them a third eye, in the PCI management of CAD.

As a review, intravascular ultrasound, is the use of ultrasound to look into the inside (intravascular) of the heart artery, just as we use ultrasound to look at pregnant ladies and gall bladders. Obviously, the ultrasound probe is different. The intravascular ultrasound probe is fixed at the tip of a catheter and introduced into the heart artery along a guide-wire, as we would during any interventional cardiology procedure.

Of course, ultrasound can differentiate tissues by their ability for sound to penetrate. Sound penetrates liquid easily and rock hard calcium very poorly. We can use this principle to differentiate tissue in the heart artery wall, namely cholesterol pools at heart artery walls, with necrotic areas will show up as liquid (which is usually colour coded red/yellow), while fibrous tissue will show up as green, and calcium spots will show up as dense white.

This machine colour-coding process is called " virtual histology " or VH for short. We know from our medical research, that the plaques that causes heart attacks are usually full of cholesterol crystals and necrosis (dead cells) tissues.

The intravascular ultrasound can also show us the layers in the heart artery wall. They give a very precise measurements of the thickness of the wall, the plaques and also exact sizing of the lumen size of the artery. These exact measurements, allow very precise placement of the exact size of stents and also very precise apposition of the stents against the artery wall. Their widespread use by the Chinese and Koreans, allow them to target their use of stents precisely and also size their stents accurately and making sure that the stents are sticking precisely, allowing the best drug-eluting stent results.

At the present, in Malaysia, there is one such intravascular sound machine in IJN and another in GH Penang. They have been up-graded to give the additional virtual histology. We are looking to get one such machines ourselves, to enhance our work.

This is one of the many lessons we learned from Beijing/Korea.

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