NEW ORLEANS—Patients who have a transient ischemic attack (TIA) have a 9.5 times greater risk of having a future stroke than those who have not had a TIA. Because the symptoms of TIA are short term, however, many patients do not perceive the event as a warning. Even some clinicians, unsure of the connection between TIA and stroke, may underestimate the future health impact of a TIA. But TIA is a predictor of stroke and other adverse events, according to researchers at the 25th International Stroke Conference, and early intervention can significantly reduce the risk of a future stroke.

TIAs—HARBRINGERS OF IMPEDING STROKE?

"Although many stroke neurologists feel that TIAs are emergencies, that opinion is not shared by a lot of our colleagues, particularly emergency department physicians and internists. In part that is because of the quality of the literature," said S. Claiborne Johnston, MD. To fill in some of those gaps, he and colleagues examined outcomes in 1,707 patients who presented with a TIA to emergency departments in the Kaiser-Permanente Northern California system between March 1997 and February 1998. The patients were followed for three months. Strokes that occurred during this period were confirmed independently by two neurologists. Dr. Johnston, Assistant Professor of Neurology at the University of California in San Francisco, discussed outcomes among the large study population.

"One quarter of TIA patients returned with some sort of adverse event within three months of their original presentation," he said. While the three-month risk of stroke was 10.5%, the one-week risk of stroke was 6%. Most of the strokes occurred soon after the TIA—half occurred in the first two days. During the three-month period, 13% of patients presented with recurrent TIA, 2.7% were hospitalized for cardiovascular events (which included myocardial infarction, unstable angina, ventricular arrhythmia, and new congestive heart failure), and 2.6% of patients died. At the time of initial presentation, only 15% were admitted to the hospital, 92% were given secondary prophylaxis, and 30% were referred for consultation.

The median duration of a TIA was 70 minutes. "This is quite different from what is in the literature. Remember, these are patients who made it to the emergency department, so they tend to have more serious symptoms than patients who might be seen in the clinic," Dr. Johnston said.

Five independent risk factors for stroke following TIA were identified: age greater than 60, diabetes, duration of TIA greater than 10 minutes, weakness, and speech difficulties (Table 1). Patients with four risk factors were at a 30% risk of having a stroke within the three months after TIA. Dr. Johnston noted that 20% of the cohort had diabetes, 60% had hypertension, 10% had atrial fibrillation, and 23% had had a prior stroke.

"TIAs are ominous signs and should be taken seriously," said Dr. Johnston. He suggested management strategies that could improve the outcome of a TIA: admission to the hospital of a higher proportion of patients presenting with TIA, the development of a holding system in the emergency department while diagnostic workup is completed, and the initiation of a more aggressive secondary prophylaxis.

TIAs IN THE PRIMARY CARE SETTING

Most patients having TIAs or strokes first contact their primary care physician, not the nearest hospital. Larry Goldstein, MD, and colleagues at Duke University Medical Center, Durham, North Carolina, studied what happens after these initial consults for first-ever TIA or stroke. Their medical record audit of 176 such patients showed that "only a very small proportion of patients evaluated in a primary care physician's office for a first-ever TIA or stroke are hospitalized, and the majority are managed without specialist consultation. Only a minority had either brain or cerebrovascular imaging studies or additional cardiac tests. Nearly one third had no evaluations performed," he reported. Dr. Goldstein is an Associate Professor of Neurology and Director of Duke University's Center for Cerebrovascular Disease.

The data included 95 patients with a verified diagnosis of first-ever TIA and 81 patients with a first-ever stroke, initially evaluated in a primary care physician's office as part of Duke's Center for Clinical Health Policy's AHCPR-funded Stroke PORT. Nearly 80% of TIA patients and 88% of stroke patients were evaluated on the day their symptoms occurred. "Only 6% of patients were admitted to a hospital for further diagnostic testing and management on the day of their initial office evaluation: 2% of patients with TIA and 10% with stroke," Dr. Goldstein reported. "An additional 3% of patients were admitted to a hospital over the subsequent 30 days, so 91% of the patients were completely evaluated as outpatients. Thirty-six percent of the patients were neither hospitalized nor had further evaluations during the first month after presentation with symptoms of a TIA or stroke."

Specialists were consulted in the management of 32% of the patients. Neurologists were consulted for 14% of the patients with TIA and 20% of the patients with stroke. Cardiologists were consulted for 13% of TIA patients and 6% of stroke patients. Vascular surgeons evaluated 6% of TIA patients and 3% of stroke patients.

Primary care physicians added, changed the dose of, or began a new platelet antiaggregant for 47% of the patients with TIA and 32% of those with stroke, said Dr. Goldstein. At the initial outpatient evaluation, primary care physicians altered the platelet antiaggregant therapy of 59% of the patients who were not hospitalized and who underwent no diagnostic studies over the next 30 days.

Eighteen percent of patients presenting with a TIA and 9% of patients presenting with a stroke had a prior history of atrial fibrillation. Of these 24 patients, 10 (42%) were receiving warfarin at the time of the index visit. The level of anticoagulation was measured in only three of these 10 patients. Although all but one of the non-anticoagulated patients had additional risk factors warranting anticoagulation, none were started on warfarin over the next 30 days.

"The need for urgent evaluation of patients presenting to their primary care physician with symptoms of cerebrovascular disease requires further emphasis. Barriers to implementation of established secondary stroke prevention strategies need to be carefully explored," Dr. Goldstein concluded.

IS AN EMERGENCY OBSERVATION CENTER THE ANSWER?

Assuming that TIA patients and primary care physicians can be convinced to move suspected TIAs more quickly to the emergency department, Rodney W. Smith, MD, suggested that a brief stay in an emergency observation center might improve evaluations and prevent unnecessary hospitalization. Dr. Smith and associates at St. Joseph Mercy Hospital in Ann Arbor, Michigan, tested a pilot program that included neurology consultation; carotid evaluation with carotid duplex Doppler, cerebral angiography, or magnetic resonance angiography; and cardiac evaluation with 2-D echo or transesophageal echo, as indicated.

Dr. Smith and colleagues compared admission rates of and costs incurred by patients with a suspected TIA who were treated in an emergency department to those treated in an emergency observation center. The control group, which was treated in the emergency department, consisted of 213 consecutive patients with suspected TIA who were drawn from the emergency department log between August 1, 1997 and May 31, 1998. The study group, which was treated in the emergency observation center, consisted of 238 consecutive patients with suspected TIA who were drawn from the emergency department log between August 1, 1998 and May 31, 1999. Data from the control group were analyzed retrospectively, while data from the subject group were analyzed prospectively.

Emergency observation center evaluation reduced hospital admissions of patients with suspected TIA in this study, Dr. Smith reported. While admission was ordered for 74.2% of patients evaluated in the emergency department, it was ordered for 44.1% of patients evaluated in the emergency observation center.

Costs of evaluating and treating patients also were reduced by emergency observation center evaluation, Dr. Smith added. Cost was reduced by 31% ($650 to $700) among selected patients (see Table 2). The median cost of evaluation for all control patients was $2,224, and the median cost for all study patients was $1,528. The study also showed that the median cost for all patients with TIA or possible TIA in the control group was $1,918 and for those in the study group, $1,236. Among patients with TIA who were hospitalized for less than three days, those in the control group incurred costs of $2,069, while patients in the study group incurred costs of $1,422.

—Janis Kelly
Contributing Writer

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