Acute Stroke

Strokes
Strokes affect 700,000 people each year, and are the third leading cause of death in the United States, accounting for about 1 in every 14 deaths. Someone in the US has a stroke, on average, every 45 seconds, and someone dies from stroke every 3.1 seconds. It is estimated that 40,000 more women have strokes each year than men. More money is spent on the care of strokes than any other condition. More than 1 million Americans suffer from difficulty in daily functioning due to stroke.

Strokes typically occur when an artery that supplies blood to the brain is blocked. This is known as an “ischemic” stroke, and it is believed to account for over 80% of all strokes. As a result of an ischemic stroke, the brain will not receive enough blood in the area of the blockage and neurons start to die of starvation from lack oxygen and energy sources. If the blocked blood vessel is not reopened, loss of brain function may quickly occur in areas controlled by the affected part of the brain. Strokes may also occur when a blocked artery bursts, causing bleeding around the brain. This is referred to as a “hemorrhagic” transformation of an ischemic stroke and represents a serious risk to the stroke victim with or without medical intervention.

Family history of stroke and prior personal history of stroke also put one at greater risk.

Risk factors
A number of medical conditions are risk factors for stroke. These include diabetes mellitus, hypertension, atrial fibrillation (one type of irregular heartbeat), and atherosclerosis, commonly known as hardening of the arteries. Diseases that cause blood to form clot too quickly or easily and are affiliated with blockages in blood vessels in other parts of the body also can contribute to strokes. Family history of stroke and prior personal history of stroke also put one at greater risk. Certain ethnic groups, including African Americans, Latinos, and Asian Americans are also more likely to get strokes than other populations.

Several symptoms can be warning signs of stroke and are cause for immediate medical treatment. For example, rapid onset of weakness or numbness, confusion, visual difficulties, and speech problems may be evidence of stroke. Additional warning signs include dizziness, loss of balance, or difficulty with coordination. Unfortunately, sometimes strokes also cause neglect or the inability on the part of the stroke victim to recognize that the stroke has occurred. For example, the stroke victim may be paralyzed on one side of their body but also fail to recognize that the affected body part even exists.

Diagnosis of stroke
In order to accurately diagnose a stroke, physicians may utilize one of several different types of diagnostic procedures. Computed tomography, or CT scan, of the brain is a type of x-ray imaging study that allows physicians to evaluate the brain for evidence of stroke and other conditions that may mimick stroke, such as tumors and infections. CT scanning may also show if normal brain tissue has suffered any damage. CTangiography or CTA, is an enhanced form of CT scanning in which a special iodinated contrast isinjected through a vein at the time the CT scan is performed. Blood vessels can then be examined for blockages, aneurysms or other causes of stroke and hemorrhage. A conventional cerebral angiogram also involves the injection of an iodinated contrast material, but this is through a tiny catheter or tube measuring approximately 1.5 mm in diameter into the arterial blood vessels to examine the flow of blood at the most detailed level. Catheter angiography also forms the basis for endovascular surgery now used to treat many forms of stroke and other cerebral vascular abnormalities.

Magnetic resonance imaging, or MRI, is another type of study that allows blood vessels and brain tissue and function to be examined. MRI is very sensitive to the identification of early brain ischemia or bleeding. MRI scanning often requires more time to perform. In an emergency, CT brain scanning remains much faster and more easily obtained in most hospitals. CT scanning is able to identify most acute hemorrhages that occur in and around the brain. In fact, most major studies evaluating patients with forms of stroke or hemorrhage have been based upon CT scan findings. If a CT is normal or “negative” but the physician remains suspicious that hemorrhage has occurred, then a lumbar puncture to may be necessary to evaluate for very subtle bleeding that could be indicative of a life-threatening condition. A lumbar puncture or “spinal tap” is performed to obtain a small sample of spinal fluid for evaluation. This involves the insertion of a needle into the lumbar (lower back) spinal canal below the level of the spinal cord to withdraw cerebrospinal fluid – the fluid that is produced deep in the brain and bathes brain and spinal cord. Spinal fluid analysis is another very sensitive indicator of hemorrhagic stroke and some other causes of neurological dysfunction.

Treatment of Ischemic Stroke
There are a number of procedures to treat acute stroke. There is still a tremendous amount that remains unknown about brain function, the response of brain tissue to ischemia, and mechanisms to prevent cell death and dysfunction before medical care can be administered. Blockages in brain blood vessels can sometimes be cleared or dissolved and the effects of the stroke on brain function reversed. In some cases, drugs that dissolve blood clot can be administered to restore blood flow to the brain. Injection of tissue plasminogen activator, or TPA, can be administered by vein to patients with ischemic stroke but no bleeding if the drug can be administered within three hours of stroke onset. Intravenous thrombolysis is currently the only therapy approved by the U.S. Food and Drug Administration based upon the findings of a single multi-center trial. However, the vast majority of stroke victims do not present for medical attention within this three hour window. Moreover, large vessel occlusions that threaten large areas of the brain do not respond well to intravenous thrombolysis For these reasons and others, physicians are working to develop more effective, safer, and faster methods to treat acute stroke.

Interventional stroke treatment from start to finish
Prior to undergoing endovascular stroke treatment which is effectively a form of surgery, patients or their legal guardian or representative must sign a consent form and will have the opportunity to have questions answered. In certain very specific cases, this type of emergency treatment can be performed in an effort to help the stroke victim with waiver of informed consent. But waiver of informed consent requires adherence to strict guidelines and must usually be performed with prior approval of the institution’s investigational review board (IRB).

An anesthesiologist will administer medications and fluids through the use of an intravenous line (IV) into a vein in the hand or arm. In some cases, general anesthesia with the patient completely asleep on a respirator is required for stroke victims who are unable to cooperate for the catheter arteriogram and endovascular stroke treatment.In many cases, the stroke patient can be treated under light sedation and can remain in constrant communication with the treating physicians. Blood pressure may be monitored through an A-Line, a thin flexible tube or catheter placed in an artery in the wrist. An electrocardiogram (EKG) will monitor heart rate and rhythm. And an oxymeter provides a non-invasive method to monitor the patient’s respiration and bloodoxygen levels. A specific type of catheter known as a Foley may be placed through the urethra, into the bladder to allow urine to drain. Anesthesiologists often monitor urine output as a simple indicator that the body’s major systems are functioning well.

The arteriogram to diagnose the location of the blockage and the pathway for endovascular treatment most often involves the insertion of a small catheter or tube into the common femoral artery, the major artery to the leg. The treating physician, usually a specialist in interventional neuroradiology or endovascular surgical neuroradiology, guides the catheter using advanced x-ray imaging technology called fluoroscopy into the site of the blocked artery. Through these catheter systems, medicine such as TPA or other agents to dissolve clot, relieve spasms, or protect the brain can be administered. Direct disruption of the blockage using balloon angioplasty or passage of the catheter through the center of the blood clot promote more rapid restoration of blood flow. Moreover, new and inventive treatments to mechanically remove the blockage are now under development that may offer even greater safety and efficacy than thrombolysis.

Once the procedure is complete, the patient will be transferred from the neuro-interventional operating room to either the Neurological Intensive Care Unit (NICU) or the Post-Anesthesia Care Unit (PACU). Following successful stroke treatment, patients must be carefully monitored for any evidence of hemorrhage into the injured brain tissue that would require emergency surgery. Their blood pressure must be carefully controlled, and heart monitoring to detect early signs of heart attack is continuously performed. Here, a heart monitor will closely monitor vital signs. This machine is very sensitive and often sounds inadvertently; this is not cause for alarm. The nursing staff will assist in changing positions, but bed rest is required. In some centers, additional medical interventions are under investigation to restore normal brain function. Eventually, the patient can look forward to a normal diet and transfer to a room on a neurological care floor. The Foley catheter and any invasive vascular monitors will also be removed prior to leaving the bed for the first time.

Patients are expected to keep the leg that underwent surgery straight for several hours. In most cases, the arterial treatment catheter is removed at the end of the procedure and a special percutaneous suture device is used to seal the hole in the artery without open surgery. A short tube may remain in place at the arterial access site for up to 24 hours after administration of TPA or other clot-busting medicine until the drug effect has worn off. Thereafter the tube can be safely removed.

The length of stay in the hospital will depend on the severity of the stroke, the need for rehabilitative therapy, and other medical conditions that may require treatment. Once at home, certain activities such as heavy lifting and driving must be avoided until the physician provides approval. Many patients, however, can resume normal activity after a relatively brief period.

All treatments for acute stroke require immediate action. When a brain blood vessel becomes blocked depriving the brain of oxygen and energy, “Time is brain” as irreversible brain damage can occur within minutes of stroke onset. Therefore, one must not hesitate seek emergency medical care whenever a stroke is suspected. Delays in seeking medical attention and treatment until it is too late are the most common way in which stroke patients present to their doctors. The importance of recognizing the symptoms and the need for urgent medical care cannot be overstated.