A joint American Heart Association and American Stroke Association (AHA/ASA) guideline defined a transient ischemic attack (TIA) as a "transient episode of neurological dysfunction caused by ischemia, but without acute infarction". Because TIA does not result in long-term disability, it has been considered a benign diagnosis. However, recent studies show that persons who experience a TIA have a 90-day risk of stroke of about 10-15%, about twice as much as persons with a recent stroke. Prompt management of stroke risk factors can reduce the risk of future atherosclerotic events.
The goal of this rapid response protocol is to determine whether this high-risk but understudied population receive an appropriate and timely diagnostic work-up and management of risk factors. The specific aims of this project are:
1)To determine whether Veterans presenting to a VAMC with TIA in fiscal year 2008 receive a timely, guideline-recommended diagnostic work-up. We will analyze VA national administrative data and validate that data by reviewing medical charts at three VA facilities.
2)To determine whether admission is associated with completion of a diagnostic workup.
3)To calculate the one-year risk of stroke, myocardial infarction, and death for Veterans presenting with a TIA and identify predictors of such outcomes.
We divided this project into stages:
1st stage: We asked the local IT staff to identify all persons at VA Los Angeles, Long Beach, and Indianapolis with an ICD-9 code for transient ischemic attack (ICD-9 code of 435.x) during fiscal year 2008 (October 1, 2007 to September 30, 2008). We reviewed the charts in CPRS to determine whether the diagnosis of TIA can be confirmed in the chart. If it is confirmed, the following data elements were collected:
-Clinical detail about the TIA episode
-Stroke risk factors
-Diagnostic workup within 30 days after TIA presentation or in the 60 days prior to presentation: neuroimaging, carotid artery imaging, cardiac evaluation, lab tests.
-Health outcomes: stroke or TIA, myocardial infarction, any hospitalization, and death in the year after TIA presentation.
2nd stage: We obtained national administrative data on the same cohort of patients to determine whether it matched chart review data. When appropriate, the programs for retrieving national administrative data were modified so that it matched the chart review data as closely as possible.
3rd stage: Once we were certain that the national administrative data were accurate, we retrieved data for all facilities
The analytic sample consisted of 2464 Veterans: 1618 (66%) who were not admitted and 846 (34%) who were admitted within one day of presentation with a diagnosis code of TIA. There was another 1159 veterans who were admitted, but with a diagnosis code other than TIA, so those patients were excluded from the main analysis.
The mean age was 68, and 25% had a prior history of stroke or TIA. Patients who were admitted were more likely to have stroke risk factors than those not admitted (older age, more likely to have atrial fibrillation, hypertension, and diabetes, all p<0.05). Patients who were admitted were more likely to have a proper neurological workup: neuroimaging of the brain, carotid artery imaging, and echocardiogram.
However, at one year, the one-year outcomes were largely similar. In unadjusted analyses, the composite outcome was not significantly different among persons admitted vs. not admitted (12.8% vs. 11.0%, p=0.29). In multivariate analyses, admission was not significantly associated with the composite outcome.
In our preliminary conclusion, persons admitted for TIA are more likely to possess stroke risk factors than those who were not admitted. However, the decision to admit was not associated with differences in one-year outcomes.
We note that the outcomes are lower than what is reported in the literature. However, it is possible that if these patients suffer a subsequent stroke, they may not present to the VA system, especially if they activate EMS and EMS automatically routes stroke patients to non-VA stroke centers.
These findings show that there is considerable room for improvement in obtaining a diagnostic workup of TIA. However, it also shows that admission for all patients may not be necessary.
We will be submitting an SDP to prospectively identify patients with TIA at 10 VA facilities. This proposal will include an intervention to expedite a timely workup of stroke risk factors for patients presenting with TIA.
- Cheng EM, Myers LJ, Vassar S, Bravata DM. Impact of Hospital Admission for Patients with Transient Ischemic Attack. Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association. 2017 Aug 1; 26(8):1831-1840.
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- Chen LL, Baca CB, Choe J, Chen JW, Ayad ME, Cheng EM. Posttraumatic epilepsy in Operation Enduring Freedom/Operation Iraqi Freedom veterans. Military medicine. 2014 May 1; 179(5):492-6.
- Ekundayo OJ, Saver JL, Fonarow GC, Schwamm LH, Xian Y, Zhao X, Hernandez AF, Peterson ED, Cheng EM. Patterns of emergency medical services use and its association with timely stroke treatment: findings from Get With the Guidelines-Stroke. Circulation. Cardiovascular quality and outcomes. 2013 May 1; 6(3):262-9.
- Cheng EM, Bravata DM, El-Saden S, Vassar SD, Ofner S, Williams LS, Keyhani S. Carotid artery stenosis: wide variability in reporting formats--a review of 127 Veterans Affairs medical centers. Radiology. 2013 Jan 1; 266(1):289-94.
- Keyhani S, Cheng E, Arling G, Li X, Myers L, Ofner S, Williams LS, Phipps M, Ordin D, Bravata DM. Does the inclusion of stroke severity in a 30-day mortality model change standardized mortality rates at Veterans Affairs hospitals? Circulation. Cardiovascular quality and outcomes. 2012 Jul 10; 5(4):508-13.
- Cheng E, Cline M, Robinson J, Myers L, Lincoln F, Bravata DM. Does Admission for Transient Ischemic Attack Lead to Differences in 1-Year Outcomes? Poster session presented at: American Heart Association Cardiovascular Disease Epidemiology and Prevention Annual Conference; 2011 May 12; Washington, DC.