BOSTON – Yiannis S. Chatzizisis Professor of Medicine, Physiology, and Engineering, Chief of the Interventional Cardiology Section and Director of the Cardiac Catheterization Laboratory at the University of Nebraska Medical Center, where he is also Director of the Cardiovascular Biology and Biomechanics Laboratory, has implanted the first Synergy Megatron stent in the United States. In separate successful procedures, two women in their early 60s became the first patients in the nation to receive Megatron, a stent created by Boston Scientific and FDA approved last month.
One woman had worsening chest pain in the last few months. In the stem of her left heart artery there was a large blockage cutting off blood flow. The other patient had coronary heart disease, with less heart pumping function than normal due to an issue in the main stem of the left artery.
The renowned doctor of Interventional cardiology explained in detail the new stent and procedure in an exclusive interview.
The National Herald: Congratulations on your achievement with the first Megatron stent implant in the US! Please explain to us what it is all about.
Dr. Yiannis S. Chatzizisis: Our work involved a number of innovations:
a. For the first time in the United States, we used a new stent, called Megatron, that is specifically designed for the stem of the left coronary artery. Megatron received FDA approval for use in patients in the United States one month ago. My medical team was the first to implant this new stent in two patients at the University of Nebraska Medical Center.
b. For the first time worldwide, we used computer simulations to plan in detail the stent procedures of the two patients who received the Megatron stent. In my research lab we have developed a unique computational simulation platform as part of our research which is funded by the National Institutes of Health. In this platform we import the specific anatomical features of each patient's arteries and then we plan the stent procedures accordingly. Our platform gives us the ability to test different stenting techniques and scenarios and eventually find the best stenting strategy precisely tailored to each individual patient.
TNH: Why was the stent named `Megatron'?
YC: The stent was given the name `Megatron' by its manufacturer, Boston Scientific. The name reflects the fact that the stent is purposefully designed for the large parts of the heart arteries, such as the stem of the left coronary artery, which is responsible for the function of two-thirds of our heart.
TNH: What is the exact purpose of this stent in the coronary arteries?
YC: Coronary arteries supply blood and oxygen to the heart. These arteries are located on the surface of the heart and are subdivided into two left and one right artery. The left coronary arteries rise from a common stem and are responsible for the blood supply to the two-thirds of the heart. The formation of blockages in coronary arteries is called coronary artery disease. Coronary artery disease is responsible for angina, heart attacks, heart failure, arrhythmias, and sudden cardiac death. It is the leading cause of death in the western and developing world. Coronary artery disease is treated either percutaneously with implantation of stents or surgically (bypass surgery). Stents are very small, tube-shaped, metallic frameworks coated with a special drug. They are implanted in the blocked heart arteries to keep them open.
TNH: How safe is the stent implant procedure?
YC: The placement of stents in coronary arteries is aided by X-rays (coronary angiography) and requires a high level of accuracy. In particular, the implantation of stents in the stem of the left coronary artery requires high precision and skills, as complications in this essential part of the heart arteries can be fatal. For that reason, these procedures in the stem of the heart arteries are considered high risk and should always be performed in specialized centers by well-trained and experienced interventional cardiologists.
TNH: Which patients are eligible for the Megatron stent?
YC: The Megatron stent has been purposefully designed for left stem procedures. What makes it different from other commercially available stents is that it is more robust in order to keep the blocked arteries open.
TNH: Does the Megatron stent have a limited life span? If so, how long is it? Is there a need for replacement after some period of time?
YC: In general, stents are placed in the coronary arteries and stay there forever. A percentage of them get blocked (5-20%), especially when they are not placed with high precision, and when patients do not control well their risk factors (i.e. hypertension, diabetes, hyperlipidemia, obesity) and bad habits (smoking, lack of exercise). Stents at the left coronary stem tend to block more often and that's why it is crucial that they are implanted by experienced invasive cardiologists following the right technique. The Megatron stent is an important tool in the hands of interventional cardiologists which allows them to perform these procedures (especially at the stem) with improved efficiency.
TNH: Does it replace open heart surgery?
YC: Coronary artery disease is either treated with conventional bypass surgery or with stents. The decision towards surgery or stents depends on many factors, including the complexity of the blockages, the presence of underlying diseases (i.e. kidney failure, diabetes, etc.) and, of course, the patient's desire. Ultimately, the decision for surgery or stents is made jointly by the interventional cardiologist, heart surgeon, and patient. The Megatron stent is a viable alternative to a bypass.
TNH: How many patients have already received this stent and how do they feel?
YC: My two patients were the first to receive the Megatron stent in the United States. These were two 60-year-old women who suffered from angina and ischemic cardiomyopathy, respectively. They were diagnosed with severe disease of the left main coronary artery. Both procedures went very well (despite their increased risk) and the patients were discharged home the next day. I had the pleasure to see them in my clinic a few days ago. They both feel great. The first patient told me that she has been able to walk her dog in the cold without angina, while the second one had already started to feel stronger and sleep better without shortness of breath. We hope that both patients will have a good and long life. The Megatron stent is now available in U.S. hospitals.
TNH: What is the required length of hospital stay for this procedure?
YC: Patients stay in the hospital for one night and they get discharged the next day.
TNH: When and how was the idea for this stent conceived and when did you start working on it?
YC: The Megatron stent was designed by the engineers of Boston Scientific. In my research laboratory we had the honor of being the first in the world to study its mechanical properties during the development phase. For that reason my clinical team was the first in the United States to use the stent in patients.
TNH: How do you feel about this success and about being the first?
YC: Whatever we do in medicine should aim to optimize patient outcomes. Megatron is a nice example of how innovative research and partnership with industry can help us make a difference. That's a very nice part of life.
TNH: What are the heart's biggest enemies?
YC: The heart's biggest enemies are the so-called risk factors for coronary artery disease: Hypertension, smoking, diabetes, hyperlipidemia, obesity, stress, sedentary lifestyle. All these risk factors are modifiable (as opposed to hereditary risk factors) with the use of medications and lifestyle changes.
TNH: Which are the most common treatable heart conditions?
YC: Coronary artery disease, heart attacks, heart failure, arrhythmias, which are closely linked. Our golden rule should be the Hippocratic principle of “prevention is preferable to cure."
TNH: What drew you to medicine and specifically to cardiology?
YC: The main reasons that attracted me to academic cardiology were the ability to help my patients through clinical observation, high-quality research, and optimal clinical care, as well as, the opportunity to pass on knowledge to younger colleagues by faithfully following the Hippocratic oath.
TNH: How do you feel each time you heal a patient?
Dr. Yiannis S. Chatzizisis: Helping our patients to live well and long is priceless!
Dr. Chatzizisis is also Director of the Cardiovascular Biology and Biomechanics Laboratory at the same university. He was trained in interventional cardiology and advanced non-invasive cardiovascular imaging at the Brigham and Women's Hospital, Harvard Medical School. He has received more than 40 international and national awards by the American Heart Association, European Society of Cardiology, and Academy of Athens among others. His research has been funded by the Behrakis Foundation, the National Institutes of Health, and Industry.