In Matters Of The Heart

Dr. Paul C. Ho
Chief of Cardiology at Kaiser Permaente

Interviewed by Melissa Moniz

How long have you been a cardiologist?

I came out of training in 1998, so it’s been close to 10 years.

What is your specialty?

My specialty is interventional cardiology. So that means performing procedures to help patients with heart disease using the catheter. It’s not open-heart surgery, instead using a hole that we puncture in the artery and threading a tiny little plastic tube into the body and into the heart area.

What has been the most notable finding within your field?

I would say the biggest thing recently is the drug-eluting stents (drug-coated stents). To go back a little, in the ‘70s people discovered a way to open up blocked arteries using a balloon to dilate up the blockages - it’s called angioplasty. As it turned out,when you do that it works part of the time, but some of the time the artery can recoil and shrink right back down over time, because it’s soft tissue and it just won’t stay open. So then we designed what is called a coronary stent. A stent looks like a tiny little spring that comes out of your pocket pen when you take it apart. The stent goes inside the balloon and it’s expanded with the balloon, but when you take out the balloon, it stays inside the artery and keeps the artery open, like a scaffold. It’s almost like a mechanical device to keep the artery open.

So that worked better than just using the balloon. However, because the stent is a foreign object in the body, the artery has a reaction to it. The reaction is almost similar to scar tissue formation, and so that scar tissue can form inside the stent. In the old days, in about 15-20 percent of these stents, the scar tissue would come back so aggressively that it would actually re-occlude the area that you just placed the stent. And over six months’time it can actually narrow it back down to 90-95 percent blocked. It was decided that these stents needed to be coated with a drug to prevent the scar tissue from forming in the area. Hence the development of the drug-eluting stents, which is the latest and the most significant development.

What has been the success rate of the drug-eluting stents?

With the old bare metal stent, the restenosis (renarrowing) rate was about 15-20 percent. With the drug-eluting stent, it is down to less than 5 percent. So essentially, if you put in one of these stents it can keep the artery open forever.

What have been some of the biggest challenges?

One of the biggest challenges - not only to me but for the entire interventional cardiology community - would be the chronically occluded arteries. Because when an artery is tightly narrowed, there’s still a channel of opening and it’s fairly easy to sneak through a small balloon to open it. But when it’s completely blocked, then you can imagine that it gets to be a lot harder.

We encounter these chronically occluded arteries all of the time. In fact, about 30 percent of the time when we go inside and just to take pictures we see these chronically shut down arteries. So for a long time we have been trying to come up with ways to get these open. Some of the cardiologists in Japan have come up with a technique that has been very effective.

Can you talk about the new technique you did recently with Dr. Etsuo Tsuchikane from Japan?

The drug-eluting stents led to more aggressive techniques to open up these tough blockages. Without the drug-coating, the chronically blocked arteries tend to renarrow aggressively. It is because of the drug-eluting stents, we know that if we can get these complex blockages open that it will stay open.

So this new technique is actually quite simple. Imagine that you have an artery that has a total occlusion (100 percent blockage). The conventional way is to use a fine metallic guide wire to poke through the blockage. Basically we try to cross the blockage and to create a small channel such that a balloon can be brought to the site of the blockage via the guide wire, like a railway system. Then when we inflate the balloon it cracks open the plaque. That’s the whole idea.

However, because these chronic total occlusions can be very difficult to cross because they have been there for a long time and can be very long, the wire can get stuck in the middle of the blockage and cannot be passed through. So the Japanese doctors came up with this technique to try to cross these blockages from the front and back ends at the same time. By utilizing the collateral blood vessels (naturally occurring channels between arteries), our Japanese colleagues developed this technique to allow for access to the back end of the blockage. This technique is called “Controlled Antegrade and Retrograde Subintimal Tracking” or CART technique.

It is hoped that by poking in the front and in the back that we can create a channel that will allow the balloon to cross to open the blockage and to follow by a drug-eluting stent placement.

How many of these procedures were done during Dr. Tsuchikane’s visit?

We picked four patients with the most difficult blockages. Dr. Tsuchikane scrubbed in with us and we were successful 100 percent. All of them were opened.

If you could offer advice on three lifestyle changes to prevent heart disease, what would you suggest?

I would say to eat healthy, and what that means is not to have excessive salt, sugar and fat. To stay active, which means at a minimum to walk briskly three times a week for about half an hour. And the third would be to learn how to relax. Don’t be overly stressed because stress, anger and anxiety are risks factor for heart disease.

Can you describe the inner-workings of heart disease?

Imagine the inside of the arteries being almost like your skin. Sometimes you have pimples and sometimes you don’t. Americans tend to build up atherosclerotic plaques early due to our lifestyle. There are autopsy studies from the Korean War, looking at young soldiers who died in battle. When they opened them up they already had fatty streaks in their arteries, the beginnings of plaque buildup in the artery. If you’re talking about prevention of plaque buildup, you need to eat very clean and stay away from the bad fats and high cholesterol foods.

But heart disease is more than the plaque buildup; plaque-rupture can lead to heart attack and can be preventable. Plaque-rupture is like when the pimples on your face come to a head and pop open. When plaques inside the arteries pop or rupture, the cholesterol-related insides can attract blood clots to form, leading to clogging of the artery. And when that happens, that’s a heart attack.

Things that you can do to prevent plaques from becoming “active” or rupture-prone, aside from eating healthy, is taking some specific medications, such as statins for cholesterol control. And stuff like controlling your lifestyle can really help, like not smoking cigarettes and controlling high cholesterol. So it’s not just the building of the plaque, but also the activity of the plaque.

 

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