We first spoke with Dr. Sharma in March 2008, after he had been using the Runthrough wire for a few months, then again in September 2008, after 2,000 uses of the wire. Today, after 10,000 uses of the wire, he shares why the Runthrough has risen to become Mount Sinai cath lab’s workhorse wire. Dr. Sharma also discusses his use of a new support catheter, the Terumo FineCross, in chronic total occlusions.
Dr. Sharma, you have come to know the Runthrough wire very well after so much use.
Our cath lab is the busiest cath lab in the country, and the Runthrough has become our workhorse wire. Aside from decreasing wire use and providing good support, the Runthrough does not cause perforation. We have only one case of perforation with the Runthrough wire after 6,000+ cases. Actual wire use has been about 8,000 since sometimes you use another wire to go to a different vessel. Even with the Runthrough, in two-vessel disease, sometimes we cannot use one wire in both vessels. You need a different wire because it has been bent, so every third patient we end up opening another wire. We have had a good experience with the Runthrough wire, and I’m very happy to say that perforation is very rare. Similarly, we have seen only one perforation with the Balance Middleweight (BMW, Abbott Vascular) wire, our previous workhorse wire, after over 100,000 uses. With the Runthrough, we are at around 8,000 wires, and have only one perforation so far. It is a very safe wire compared to our other hydrophilic wires, which are basically the PT Graphix (Boston Scientific), or Whisper or Fielder wires (Abbott Vascular). With these wires, you have one wire perforation in just about every 250-300 cases. The advantage of hydrophilic wires is that they can go to various tortuosities, but the disadvantage is if the wire goes a little further down and into a small artery, then just keeps going. That is why hydrophilic wires should not be workhorse wires. During device manipulation, when you are pushing and pulling the devices, the wire may go into the branches and hydrophilic wires are notorious for causing wire perforation. We have not seen this with the Runthrough wire and that is why I feel very positive about the wire.
Where has the Runthrough been most useful?
In a large vessel tortuousity, for example, an angulated right coronary artery or angulated circumflex, the Runthrough is very good. In these angulated vessels, once you have the wire downstream, you generally do not need the buddy wire technique with the use of the Runthrough wire. Use of the buddy wire technique in our cath lab, which used to be in about 15-16% of cases, has dropped to about 5-6%. There is a limitation to the Runthrough wire, which I really want readers to appreciate. With bifurcation lesions, operators often leave the wire in the side branch, and then put a stent in the main vessel. We call this a jailed or trapped wire. At Mount Sinai, we routinely leave the BMW wire and sometimes a hydrophilic wire in these side branches. In the beginning, after being comfortable with the Runthrough in the main vessels, I have two experiences of leaving this wire in the branch where I distinctly remember it was very difficult to pull the wire out. If we know that the wire is trapped behind the stent struts in a branch, it may give resistance. If there is no resistance, you can pull it out after disengaging the guide catheter. You pull the wire with a little force and it comes out. However, in one patient about 9 months ago, it was very difficult. As a result, I told all my attendings and fellows not to leave the Runthrough in the side branch. I lecture at many places and at one hospital, they told me of a similar experience where a Runthrough wire was trapped in the vessel. They could not pull it out and the patient needed to go for surgery to take the wire out. We now know that the Runthrough wire should not be left in the side branch. We no longer do this at Mount Sinai and it is part of our protocol. BMW or hydrophilic wires can be left without any problem, but not the Runthrough.
You’ve always emphasized that the database at Mount Sinai cath lab is crucial in measuring aspects of wire usage. Can you tell us more about it?
At Mount Sinai, every patient who gets a coronary intervention becomes part of a very solid, detailed and extensive coronary intervention database. (We do have a database for peripheral procedures and one for aortic valvuloplasties, but as yet they are a little primitive). For the last four years, the number of coronary interventions have been anywhere from 4,500 to 4800 per year. We started the database in 2000 and it now has 30,000+ cases. For every patient that gets a coronary intervention at Mount Sinai, we capture all their demographics and baseline clinical conditions, angiographic findings, and procedural details. A research coordinator sees every patient before they go home, so patients are followed in-hospital, at 30 days (via a phone call) and then between 12-15 months post procedure. So, right now, for example, the patients from late 2007/beginning of 2008 have already received their 12-15 month phone call. That last phone call has been done for about 20,000 patients in the database. The phone call is IRB-approved. In our consent, we ask the patient permission to call — nowadays you cannot do anything without taking consent from the patient — so that we actually have consent that details the procedure and a periodic telephone follow up. Our database is what I would call “homegrown.” Back in 1996, when I became director of the cath lab at Mount Sinai, I really wanted to have an extensive database of patients. It took me a little while to find what I needed. I came across a company called SoftLink (www.softlinkinternational.com), from Ahmedabad, India, and brought them here. We started the process of creating a database in 1997. At that time, it took us about two to two and a half years to create our research database. By late 1999, we had really made it to our liking. (We do have some patients from 1999 in the database also, but they are not complete records.) At the end of 2000, all of the interventional details were set up in our database. SoftLink continues to maintain it. In our field, things do change every few months, in terms of the technique, the devices, and equipment, and so we keep asking them to upgrade and modify the database. It has been very cheap. I think it cost only about $20,000, and we pay about $15,000 per year for routine maintenance, but if we have major alterations, the database designers charge extra. If anyone asks a question, it’s very easy to find the answer, because the database holds such a large number of patients. You can ask one simple question, such as “male or female?”, but if you want to know how many males about 75 years of age had an left anterior descending artery (LAD) occlusion and a Cypher stent (Cordis Corp.), we can do that, but even that analysis will take 10 minutes. Narrowing the output, for example, from 2006 to 2008, means it will come out more quickly. We are able to query output of any kind from the database. Now, if you ask, what has been your wire use since beginning with the Terumo Runthrough wire, which was about two years ago, the answer is that our overall wire use has declined. Some of our operators don’t use Terumo wires, however. I can tell you only our overall wire use per patient. With 4,500 patients in 2007, wire use was about 2.1 (94,00 guidewires), but in 2008, wire use was 1.6. Starting in 2008, between 65-70% of the wires used are Runthrough wires. However, there is a slight caveat in that analysis. Our stent changed as of July 2008, when we began using the new, more trackable Xience V (Abbott Vascular). Before that, the majority of stents we used were Cypher (Cordis) or Taxus (Boston Scientific). The Xience V, a second-generation stent, is more flexible, so some of the reduction in wire use is probably related to the type of stent we are using. We have sent an abstract to the American College of Cardiology which compares the stent utilization at Mount Sinai cath lab from the last 6 months of 2007 to the last 6 months of 2008. We wanted to see if there was any difference in terms of the procedure time, side branch closure, wire use, pre and post dilatation, dye amount and most importantly, time of procedure. We did find that the wire usage in that particular analysis, which included Cypher (later half of 2007) versus Xience V (later half of 2008), declined from 2.1 to 1.6 in 2008. But it’s also important to note that in 2007, the BMW was our workhorse wire and 2008, the Runthrough became our workhorse wire. So clearly we can attribute some of the decline in wire usage to the increased use of the Runthrough wire.
Tell us about your use of the FineCross catheter for chronic total occlusions (CTOs).
With a tough lesion, you go for support, since you want to push the smallest device into the total occlusion and then exchange for a extra-support wire. For the support catheter in this situation, we have tried products from various companies, and then Terumo came in with the FineCross. We have found it to be very, very useful. It gives you good support. It’s rare that the wire has gone and FineCross will not cross the lesion. When we were using a 1.5mm balloon, even a 6mm balloon, the wire would go and in some cases balloon would not cross the lesion, but 99.9% of the time, the FineCross will go through these tough lesions. Perhaps one case in 700-800, it won’t go. After crossing, we change to a stiffer wire and complete the procedure with a balloon dilatation. Our current technique for total occlusion intervention is to start with a Runthrough or Fielder wire to the lesion, and then change to a stiffer wire, usually the Asahi Miracle Bros wire. Use of the FineCross catheter allows us to change the wire and go through this tight occlusion.
Some have argued against opening CTOs by saying that these patients are generally asymptomatic and that in opening the vessel, you lose the collaterals that had formed during the occlusion. What’s your thinking?
An interesting question, because we now have appropriate guidelines as to who should have percutaneous coronary intervention. For a one-vessel CTO, if the patient is asymptomatic and doesn’t have significant ischemia, we know that it should be left alone. It’s been shown that opening the vessel does not benefit the patient. In some cases, it may even cause harm. By opening the vessel, you have now closed the collaterals. You have put in a stent. If restenosis occurs or the vessel later has thrombosis, the collateral protection is gone and the patient has an acute event. Opening CTOs has really come under scrutiny. We have to be very cautious and have justification as to why we are opening the CTO. Let’s take the example of a patient with some angina, a positive stress test, a 90% lesion in LAD and totally occluded right coronary artery. For the past several years, our response has been to put a stent in the LAD and bring the patient back to open the right coronary artery. What the new guidelines state is that unless you document that this patient is symptomatic with the total occlusion or has significant ischemia — not mild or focal, but significant — you should not open this totally occluded single vessel. This is an ongoing debate. There is some data to support that if you have a totally occluded artery, if a second artery then has a blockage, you may go into shock. There are limited data, but most of the interventionalists in this field believe that if a totally occluded artery remains asymptomatic with not-significant ischemia, it should be left alone.
Dr. Sharma can be contacted at Samin.Sharma@mountsinai.org
More information is available on the Runthrough wire at http://www.terumois.com/