• Stroke: Death of brain cells from interruption of their blood supply.
• Ischemic stroke: Blockage of an artery to the brain by a clot forming locally or traveling from the heart; accounts for 85 percent of strokes.
• Hemorrhagic stroke: Bleeding either within or on the surface of the brain, often due to the rupture of an aneurysm or dilated artery; accounts for 12 percent of strokes.
• Transient ischemic attack: Temporary reduction of blood flow to an area of the brain with reversible symptoms when flow resumes; a TIA is often a forerunner of a stroke.
A middle-aged man arrives by ambulance at an emergency room at a small hospital 60 miles away from Chattanooga. Abruptly, he had lost speech and movement of his right side.
The ER physician diagnoses an acute stroke and notifies the Erlanger Southeast Regional Stroke Center. An air ambulance is dispatched. Lab studies are obtained in-flight to determine if subsequent procedures will be safe.
Upon arrival at Erlanger, the man embarks upon a tightly coordinated path of precise diagnosis and treatment. A series of imaging procedures shows a large area of brain at risk of death. An angiogram displays a clot within his skull, blocking an artery to the left side of his brain. A specialized team of vascular neurologists and interventional radiologists determines the most appropriate course of action and, after consultation with the patient's family, proceed.
A unique catheter is employed to retrieve the clot. A metal stent or sleeve is left in place to assure that a narrowed artery will remain open. His symptoms largely resolve. Outpatient physical therapy will address some lingering weakness in his right arm.
Stroke, the fourth-leading cause of death in the United States, is the leading cause of adult disability. The death rate from stroke in some counties around Chattanooga is three times greater than the national average because of increased rates of obesity, diabetes and vascular disease, all risk factors for stroke.
Remarkable advances in the diagnosis and treatment of stroke victims bring hope where once there was despair.
Because approximately 2 million brain cells or neurons die each minute that blood flow is interrupted, time is critical in evaluation and treatment. Ongoing educational efforts assure that emergency response teams and emergency rooms in the 50-hospital, 50,000-square-mile area served by the regional stroke center diagnose stroke promptly, initiate therapy and launch the transfer process.
Clot-dissolving medication represented the first breakthrough for stroke treatment. Approved for stroke use in 1996, the first drug had to be given intravenously within three hours of onset of symptoms. Benefits were limited. Bleeding was a major complication. Direct delivery of the drug by catheter to the site of a clot sometimes improved outcomes. A new clot dissolver in the final stages of government-sponsored clinical trials extends to nine hours the interval during which drug therapy may show benefit.
In the mid-1990s, the happy confluence of a group of specialists at Erlanger led to research and development of new and more direct approaches to blood-flow restoration. A delicate, intra-arterial catheter with a corkscrew configuration at its tip allows clots to be snagged and removed from arteries within the head. Stents can be placed to correct narrowed arteries or tears in the inner lining of arteries. This method of therapy extends to eight hours the window of opportunity to relieve blockages of critical arteries. Clinical outcomes are improved, particularly in large strokes when larger clots must be dissolved.
The Erlanger Stroke Center participates in a clinical study to evaluate a device (PhotoThera) that sustains the life of neurons in a vulnerable area for additional hours. This technology involves external application of near-infrared laser energy. This may provide vital time for more direct interventions.
Yet another study involves the implantation of a small device that causes the arteries within the brain to dilate and thereby deliver an improved, brain-sustaining blood flow.
In partnership with stem-cell experts around the country, the Erlanger Stroke Center has launched its first study to evaluate the placement of stem cells within the area of brain damaged by recent stroke. These stem cells are derived from normal human tissue from healthy volunteers.
Neurosurgeons and an otolaryngologist complement the Erlanger team.
In the past eight years, the number of acute stroke patients treated at the Erlanger Southeast Regional Stroke Center has tripled to more than 1,800 yearly. A senior member of the stroke team is available in-hospital around the clock. An imaging and intervention suite is continuously available.
Until my retirement from clinical practice in 2004, an acute stroke often carried a bleak outlook. There was little direct intervention available. We could provide supportive care and hope that the subsequent disability would not be too severe.
Innovative treatment and ongoing research in ischemic stroke offer a radically improved prospect for survival and improvement for victims. Precise, delicate diagnostic and treatment options are evolving steadily. The key to a successful outcome is prompt recognition of symptoms so that referral to a comprehensive stroke-treatment center can be expedited.
Coming May 31: The stories of two stroke victims.
E-mail Clif Cleveland at email@example.com.