Ranking only behind heart disease and cancer, stroke is the leading cause of death among Americans. Each year, approximately 750,000 people in this country suffer strokes with 160,000 of those occurrences resulting in death. Beyond the life-threatening aspects of a stroke lie the prospects of paralysis, inability to speak, and loss of vision among other long-term disabilities.
Local Strides in Prevention and Treatment
By Mike Haskew
Who is at Risk?
Southeast Tennessee and North Georgia are in the heart of the stroke belt, a region of the country in which stroke occurrence is roughly three times the national average.
According to Dr. Thomas Devlin, medical director of the Erlanger Southeast Regional Stroke Center, “We live in the stroke belt, and counties around Chattanooga have up to 300 percent higher stroke incidence than the national average. By 2050, the number of strokes per year in the U.S. is estimated to be greater than one million, and we are right in the epicenter of it.”
“We have an older population in the South, our diet is very rich in fatty foods and high cholesterol, which favors stroke and a lot of smoking goes on here.” He continues, “We have a lot of obesity starting in our children. So, by the time they become adults they are prone to stroke. In addition, although we have a lot of very good medical facilities here, people do not always avail themselves of medical treatment.”
Strokes strike individuals of all ages – children, adolescents and adults. For an aging population of baby boomers, a revealing statistic suggests that the risk of stroke doubles each decade after the age of 55, while about 25 percent of strokes occur among individuals under the age of 65.
Up to 80 percent of strokes are preventable, and their treatment is advancing at a more rapid pace than any area of medical science. A primary weapon in the battle against stroke is education. The warning signs of stroke include the following:
• Sudden, severe headache of unknown origin
• Sudden trouble with vision in one or both eyes
• Sudden confusion, difficulty in understanding or speech
• Sudden weakness or numbness on one side of the body, the leg, arm or face
• Sudden difficulty walking, dizziness, or loss of coordination or balance
With the onset of any of these symptoms, individuals should seek medical attention immediately. Options for treatment become more limited or challenging with the progression of time.
Types of Strokes
There are three major types of strokes: transient ischemic attacks (TIA), hemorrhagic strokes and ischemic strokes.
TIAs are often called mini-strokes, and symptoms are the same as major strokes. With TIAs, blood flow through an artery is blocked for a brief period, possibly only a few minutes. However, about 15 percent of major strokes are preceded by a TIA.
Hemorrhagic strokes account for about 13 percent of all strokes and involve the rupture of a weakened vessel which bleeds into surrounding tissue. Such strokes may occur in aneurysms, weakened areas of a vessel wall which balloon, or due to arteriovenous malformations. Blood pools in the brain and creates excessive pressure.
Ischemic strokes, which account for up to 87 percent of all strokes, occur often as a by-product of atherosclerosis, the accumulation of fatty deposits along the walls of a blood vessel, obstructing blood flow through the arteries.
Risk and Prevention
Despite the daunting challenges, those engaged in both stroke prevention and treatments are on the offensive.
“People can reduce their risk of stroke through several lifestyle changes,” relates Dr. Ian Hamilton of Hamilton Medical Center in Dalton. “We deal with strokes every day, and right at the top of the list is to immediately stop all tobacco use, particularly smoking. Maintain rigorous control of hypertension (high blood pressure) and cholesterol levels. There are genetic factors related to stroke, but lifestyle is a major contributor.”
A healthy diet, regular exercise, watching weight, and reducing stress each help lessen the risk of stroke. Individuals diagnosed with diabetes, high blood pressure, high cholesterol, or other conditions should follow their physicians’ orders and take medications as prescribed.
In 1996, the clot-busting drug tPA was approved by the Food and Drug Administration, and it was the first treatment for stroke on the market. “Prior to that there was no treatment to get the clot out of your head,” remarks Dr. Devlin. “Today tPA is the only drug that is approved for stroke. In some cases it is the best therapy, but overall the benefit is to decrease stroke risk. It has caused improvement in 12 percent of patients who received the drug within three hours of onset, but there is also an increased risk of bleeding.”
Treatment for hemorrhagic strokes is not as advanced as for ischemic strokes. Some options may include preventive treatments such as the introduction of coils to occlude aneurysms and glue therapy. Endoscopic devices may be surgically inserted to remove clots. Much of the treatment for hemorrhagic strokes depends on locating the bleeding which occurs.
As the search continues for better drugs, some strokes are best treated by interventional therapy, physically removing the clot. The Merci device utilizes a corkscrew and places a wire through the clot. A catheter delivers the device and forms a cocoon around it. Eventually the entire apparatus and the clot are slowly retrieved. The Penumbra System, an aspiration device which actually sucks the clot out of the brain, and a variety of stents are also used.
An interventional cardiologist with the Chattanooga Heart Institute, Dr. Brian Negus regularly performs procedures to treat atherosclerosis of the carotid artery in the neck. When a narrowing is detected, a stent is sometimes placed in the artery to support the walls of the vessel and restore adequate blood flow. An angioplasty, the introduction of a small balloon which inflates to open the affected area, is usually performed along with the placement of the stent.
“You can present with a stroke or mini-stroke,” commented Dr. Negus, “and a lot of times people will get an ultrasound of the neck or some other procedure to find a blockage. Cardiologists also listen to patients’ necks and sometimes find asymptomatic people with a whooshing noise which can indicate a blockage.”
When a stent and angioplasty are determined to be the best course of treatment, the patient usually receives local anesthesia and instruments are introduced through the femoral artery of the leg in similar fashion to an arteriogram. At times, narrowing of the carotid artery may be corrected through endarterectomy surgery, during which the patient is under general anesthesia, blood flow is temporarily redirected, and the artery is cleared.
Leading in Stroke Care
One of the finest treatment facilities in the world is right here in Chattanooga. At Erlanger Southeast Regional Stroke Center, pioneering research is being conducted along with clinical trials and the implementation of the latest treatment options. One of the busiest stroke centers in the country, the facility treated 1,275 strokes in 2009.
“If you look at a list of interventional centers, we are the second busiest in the United States behind the University of Pittsburgh, and we are one of the most experienced in the world,” comments Dr. Devlin. “The problem is huge numbers of strokes affecting people of all ages, and in response to what is basically a medical crisis in our community, we have created one of the most advanced stroke centers in the world. We cover about 55,000 square miles.” Referrals come to Erlanger from major cities such as Atlanta, where hospitals currently do not have such large, comprehensive stroke teams in place.
“We have six interventional radiologists that work together as a group, and we do it all day and all night,” says Devlin. ”This has been a group effort between the hospital, radiology, and neurology. What the hospital has had the foresight to do is create the team and support it infrastructure-wise.”
Erlanger also serves as the hub of the National Stroke Intervention Training Center, a non-profit endeavor under the auspices of the Pleiades Foundation. Devlin says, “We partner with Erlanger Hospital and the UT College of Medicine. Doctors come and train and get credit through the College of Medicine. We are underwritten by medical device companies which have supported us as their single training center, the only one of its kind in the United States. We have three offerings, and the first is a neurointerventional course led by Dr. Blaise Baxter. I run a second course for stroke neurologists, and a third course trains hospital administrators on contracting with neurologists and interventionalists, growing stroke programs, and finances.”
Medical professionals from major cities such as Atlanta and Nashville, as well as from nations including Vietnam, Dubai, and India have received training in Chattanooga.
“We have taken a medical liability in the stroke belt and turned it into an opportunity to learn and research,” commented Dr. Devlin. “The mission of the stroke center is clinical care, research and education, and we are pretty much international leaders in all of those. That is the message. Emphasis is on the team, and we have developed an unbelievably organized team of people committed to this work.”
Research and Advancement
“Research options come in two categories: new drugs and new devices,” Dr. Devlin notes. “The drug getting a lot of attention now is Desmoteplase. We call it the “vampire bat drug.” A German chemist studied the saliva of a vampire bat, and it is now in pivotal clinical trials in the U.S. and abroad. We were the first center in the U.S. to give that drug to a human in the trial.”
Also undergoing clinical trials is the Israeli-developed BrainsGate device, about the size of a small toothpick. Implanted within a canal in the roof of the mouth, BrainsGate uses electrical stimulation to dilate arteries. Erlanger was the first center in the U.S. to implant the device, and its physicians have the most implantation experience in the world.
“Dr. Peter Hunt is the pioneering surgeon behind implanting here and runs a surgical team which I am a part of,” says Devlin. “He is the star surgeon for learning how to put these things in. He is unbelievably gifted at doing this.”
International pivotal trials are about to begin with the PhotoThera devices, which could allow a window of treatment to extend to 24 hours from stroke onset. PhotoThera involves two minutes of radiation therapy to 20 spots in the brain, allowing neurons to stay alive longer. PhotoThera may also eventually be used in tandem with other treatments.
“The combination of drugs and other therapies is where we are going,” observes Devlin. “We are taking these incredible technologies in the pipeline and giving patients great medical care and companies incredible data. Our patients have the benefit of these treatments here and now, when there would otherwise be no alternative.”
The promise of even greater advancements offers hope for the future. Rapid progress is being made, even in our own community, resulting in more positive outcomes for patients.
Mike Haskew is a graduate of the University of Tennessee at Chattanooga and holds a degree in history. He is a native Chattanoogan and is currently an executive with First Citizens Bank.