Giorgio Biasi, M.D., F.A.C.S., F.R.C.S., received his medical degree from the University of Milan Medical School in 1965 and continued there to complete post-graduate training in General Surgery and Angiology, and Vascular Surgery. Over the course of his career, Dr. Biasi has belonged to, and served on, a staggering number of boards, committees, societies and associations dedicated to his field. Among these includes a position as chairman of the European School for Vascular and Endovascular Surgery and reviewer for JAMA and the Medical Science Monitor. Dr. Biasi has authored about 260 scientific papers in national and international journals, and written chapters in 37 books. Dr. Biasi has also been a visiting professor at nine prominent universities located in the U.S., Asia, Europe, the Middle East and Africa. Currently, Dr. Biasi serves as chief of the Vascular Surgery Unit at the San Gerardo/ Bassini Teaching Hospital, full professor of Vascular Surgery and chairman of the department of Surgical Sciences and Intensive Care at the University of Milan, Bicocca. Veins1 caught up with Dr. Biasi at the 32nd Annual Veith Symposium after his lecture on a new visual diagnostic method that can quantify a patient’s risk of brain embolization.
Veins1: So tell about what sort of data you were discussing at your presentation.
Dr. Biasi : The third leading cause of death in the Western world is stroke, so it is a serious problem. Up until the ’70s and the ’80s the cure for stroke was basically the prevention, which consisted mostly of medical treatment and that was all. Then a paper and a publication of the NASCET Study appeared, which clearly demonstrated the superiority of carotid endarterectomy compared to medical treatment, without a doubt. Following that publication, the number of carotid endarterectomies increased over the years and the results of carotid endarterectomy were very good. Then what happened in the ’90s was the appearance of a new procedure, carotid stenting.
Carotid stenting became more and more popular to the point that some specialists, like cardiologists or radiologists, claimed that it would be the end of carotid endarterectomy and also that the presence of a plaque at the carotid bifurcation is not a surgical disease anymore.
Now actually all the studies in the ’80s and ’90s and even now (even very well-designed randomized control trials) are taking into account the percentage of stenosis and the presence or absence of neurological symptoms to indicate, or not, any kind of procedure, such as stenting or carotid endarterectomy. But the situation is that these parameters are becoming obsolete. Why are they becoming obsolete? Because the new technology, especially ultrasound, has been able to study and assess the plaque in the carotid bifurcation and demonstrate that there are some plaques that are at very high-risk for embolization and some are not, or some are less. In the ’90s we started examining the carotid plaques and the possibility of having a defined number which could identify the risk of embolization for any given plaque. Usually when a surgeon goes to an ultrasonographer and asks ‘how’s the plaque?’ often the reply is “well the plaque is so-so, not too bad, or it’s very bad plaque”. A diagnosis like this means nothing especially if you consider that there is a discrepancy with a need for a clearly defined percentage of stenosis and the presence or absence of neurological symptoms.
We wanted to identify a system which could be reliable and define exactly what the risk of brain embolization of the plaque is and we found the answer in the GSM – the GSM is an acronym for Gray-Scale Median. The fundamental thing was the standardization or normalization of the GSM of the plaque. The problem was to make sure that the GSM of a plaque as determined by you in your hospital or by another ultra-sonographer in, let’s say, New Delhi, for the same patient and the same plaque, was the same. So what you want to do is to normalize, to standardize the value of the GSM , and that can be done with Adobe Photoshop with a procedure that can easily be acquired by all ultra-sonographers. At this point the GSM gives you a precise number that can utilized to identify the feature of the plaque and quantify the risk of brain embolization for that given plaque at that given moment.
Veins1: What was this study?
Dr. Biasi : The name of the Study is ICAROS (Imaging in Carotid Angioplasty and Risk of Stroke).
Veins1: Is it going on now?
Dr. Biasi : The Study has been concluded and the results have been published in Circulation in 2004.
It ran from December 2001 to December 2003 (two years). We recruited 418 patients that were included in the study and we recorded the neurological complications in our patients. With the GSM we found that those patients with a GSM of the plaque less than 25 (very echolucent, friable plaques) presented with 7.1 percent neurological complication, and those patients with non-echolucent plaque and a GSM over 25, had a significantly less number of neurological complications.
Veins1: Can you tell me what goes into that number; the 25? What goes into the GSM – what are the different factors?
Dr. Biasi : The different factors are that the GSM relates to the echolucency of the plaque. A very echolucent plaque means that you have a very friable, soft plaque, which may be hemorrhaged inside. While when you have a non-echolucent plaque, the plaque is mostly fibrotic and consequently more stable.
Veins1: So if it’s echolucency that means it’s softer?
Dr. Biasi : Yes, but when you say “soft,” you may have an approximate idea of the real situation. But when you say it’s 21, you know exactly what the situation is. The cut-off point of 25 was not defined arbitrarily by us but it was derived by the ROC curve. Then we started assessing the GSM in all our patients as candidates for carotid stenting. We decided that when you have a patient with a GSM less than 25, that patient should not be candidate for carotid stenting and should go under carotid endarterectomy.
We also, in our ICAROS study, analyzed the relationship with various brain protection devices and we found that that when you have an echolucent plaque with a GSM less than 25, the presence or not of a distal brain protection device makes a non-statistically significant difference. In other words, the difference is made, not by the device, but it’s made by the echolucency of the plaque. In fact, if you use a non-distal protection device, a proximal protection device which means a flow-reversal system, then at that point the type of protection device makes a difference.
So in other words, if you have an echolucent plaque and you have, or you want, in any case to do a carotid stenting, then you should not use a distal brain protection device, but a proximal brain protection system.
The beauty of the study is that it’s very easy… you can find Adobe Photoshop any place, and its cost is about $150. Then you have to learn how to assess the GSM. And as a matter of fact, we are available to give courses around the world to teach it. But that takes time and especially it takes time for some colleagues to realize that the assessment of the plaque before you perform any carotid procedure is important. Sometimes it may happen that if you’re a cardiologist and you are performing a coronary angiogram and you happen to see a stenosis and you put one or more stents in the coronary territory, you might wish, when you are retrieving your catheter, to do a carotid angiogram and in case you see a stenosis at a carotid bifurcation, decide to put a stent. This procedure, conducted without knowing anything about that plaque, should be absolutely reprimanded! Nevertheless, some people claim that the assessment of the plaque is not only complicated but useless and so they are reluctant in doing this kind of examination. But I wouldn’t like to have someone do that to me. So that’s what the ICAROS Study is for - to assess the plaque. What we’re trying to do at this point is to say that in the guidelines for the treatment of carotid bifurcation stenosis, for any procedure a precise evaluation of the plaque should be mandatory.
Veins1: Can you tell me a little bit about how you use Photoshop to determine the echolucency?
Dr. Biasi: Sure. You have the image on your echo-doppler, now using the Adobe Photoshop program the pixels of the plaque are examined and entered into the program. At this point the Adobe Photoshop goes from zero – which is very transparent, very dark, very black - to a maximum, which is very echoic, very bright.
Veins1: This is from 0 to 250 pixels?
Dr. Biasi: Right. Now, you want to standardize the image because if you have an image like that, as we said, it might be different in different places by different ultrasonographers. With the help of Adobe Photoshop, what you can do is to select an area of the blood which is absolutely black and then you fix zero there. Then you should select an area (preferably adventitia) to establish the most echoic portion of your image.
Veins1: Why adventitia?
Dr. Biasi: Adventitia is the most echoic, healthy portion of the arterial wall and is very white.
Veins1: So essentially you’re measuring the pixels in the plaque?
Dr. Biasi: Right
Veins1: And more pixels mean it’s less echolucent? And fewer pixels essentially mean it’s softer, looser, not as dense, and easier for pieces to come off…?
Dr. Biasi: To come off and embolize to the brain. But you have to make it very clear that there are many parameters that can influence the risk of embolization from a plaque.
One possibility is if you have a hemorrhagic core inside the plaque and if you look at the dimension of this hemorrhagic area, the more large the area, the more possibility you have to embolize. Then, if you have this hemorrhagic area very close to the base of the plaque, or on top, close to the fibrous cap of the plaque, the risk of embolization is quite different. Now if you put all these parameters in a computer and you want to determine exactly how these parameters will influence the risk of embolization, statistically you would need over 500,000 patients – so that means, no way. Therefore you will never have any significant response to the exact risk evaluation of your patient if you plan to include all these parameters. The GSM gives a very reasonable, reliable, fast and inexpensive assessment of the risk of embolization.
Veins1: Tell us a little bit about your experience in the field, why you went into the field and what you like about it?
Dr. Biasi: My mentor was a general surgeon and in the early ‘60s he started with vascular surgery in Italy and in Europe.
I entered his team when I graduated from medical school because I thought that vascular surgery was a new specialty, very clean, very precise, very delicate and in addition that he was a very good surgeon, so that is what convinced me to start.
I then specialized in vascular surgery and I have been practicing vascular surgery for almost 40 years. In the early ’90s, when all these stories of endovascular procedures came out, I decided that it was going to be a very interesting and promising field. Speaking to my colleagues, vascular surgeons in my country and other countries, they were saying to me, you are a betrayer, you are crazy, why do you want to be involved in these new procedures, putting yourself to a challenge?
I remember at that time, when Juan Carlos Parodi started with the new AAA endovascular treatment, I was not satisfied with that kind of endograft, but when AneuRx, which later became Medtronic, came out with the Fogarty endograft, I thought that was very convincing and I decided to get involved with the animal and then clinical studies with the implant of that device.
At that time I went to San Francisco and we did a number of cases on goats. We were finally satisfied with that endograft and when I came back to Italy with my friend Franz Moll from Holland, we performed the first cases in Europe with this new endograft and we were very satisfied, we enjoyed that, and so I started to treat AAAs endoluminally.
My personal experience in the treatment of carotid bifurcation stenosis is some 1,500 carotid endarterectomies and some 200 carotid stenting. I perform carotid stenting in approximately 15 percent of cases.
I think that the assessment the GSM would be very helpful and decisive when planning what to do and what kind of procedure to apply.
The best medical treatment, which has recently preponderantly reappeared on the scene, is probably now changing the scenario. Medical treatment now includes statins and other new drugs that may subvert the results of what was achieved in the ’70s and ‘80s. The TACIT Study, which is a transatlantic study between Europe and the United States of America, is a three-arm randomized controlled trial and the three arms are: Best medical treatment alone, best medical treatment combined with carotid endarterectomy and best medical treatment and carotid stenting. Interesting information may result from this study and perhaps it may appear that the best treatment for carotid plaque in the future is to do just the medical treatment.