Despite two previous Perspective pieces on the topic of stroke last year [“Is thrombolytic therapy for stroke the standard of care?” and “Stroke/TIA evaluation and treatment both a medical and legal quagmire“], both patients and attorneys continue to have questions about treatment standards for this often devastating condition. In an effort to make this as simple as possible, given the state of flux of the standard of care in this area, this Perspective presents a current summary of what one should know when evaluating whether the care of a stroke victim has met that standard as it exists today.
Key Points:
- Intravenous tPA (tissue plasminogen activator, a “clot busting drug”), the only approved treatment of acute ischemic stroke. must be given within 3 hours of symptom onset. Its efficacy and safety, when given beyond that period, are not established, although there has been some indication from a pooled analysis of the randomized trials that there may be benefit up to 4.5 hours (ECASS 3 Trial).
- Time of onset of the stroke must be accurately determined. Quoting AHA guidelines: “The single most important piece of historical information is the time of symptom onset. The current definition of the time of stroke onset is when patients were at their previous baseline or symptom-free state. For patients unable to provide this information or who awaken with stroke symptoms, the time of onset is defined as when the patient was last awake and symptom free or known to be “normal.” Often a patient’s current symptoms were preceded by similar symptoms that subsequently resolved. Currently, for patients who had neurological symptoms that completely resolved, the therapeutic clock is reset, and the time of symptom onset begins anew.”
- Truly informed consent, whether treatment is given or not, is critical, because patients and families are aware that stroke treatment is available. But they don’t understand the risks, benefits and constraints.
- A CT scan is mandatory before treatment. It is rather insensitive in detecting small strokes, especially in the posterior fossa (back of the brain.)
- Imaging of the blood vessels using contrast is generally only useful if intravascular interventions are readily available in the institution. This pertains most often to vertebral artery dissections or intracranial clots.
The following summary of the characteristics of stroke patients eligible for tPA therapy is reprinted from “Guidelines for the Early Management of Adults With Ischemic Stroke” from the American Heart Association.
Characteristics of Patients With Ischemic Stroke Who Could Be Treated With rtPA
- Diagnosis of ischemic stroke causing measurable neurological deficit
- The neurological signs should not be clearing spontaneously.
- The neurological signs should not be minor and isolated.
- Caution should be exercised in treating a patient with major deficits.
- The symptoms of stroke should not be suggestive of subarachnoid hemorrhage.
- Onset of symptoms _3 hours before beginning treatment
- No head trauma or prior stroke in previous 3 months
- No myocardial infarction in the previous 3 months
- No gastrointestinal or urinary tract hemorrhage in previous 21 days
- No major surgery in the previous 14 days
- No arterial puncture at a noncompressible site in the previous 7 days
- No history of previous intracranial hemorrhage
- Blood pressure not elevated (systolic >185 mm Hg and diastolic >110 mm Hg)
- No evidence of active bleeding or acute trauma (fracture) on examination
- Not taking an oral anticoagulant or, if anticoagulant being taken, INR <1.7
- If receiving heparin in previous 48 hours, aPTT must be in normal range.
- Platelet count >100 000 mm3
- Blood glucose concentration >50 mg/dL (2.7 mmol/L)
- No seizure with postictal residual neurological impairments
- CT does not show a multilobar infarction (hypodensity >1/3 cerebral hemisphere).
- The patient or family members understand the potential risks and benefits from treatment.
- INR indicates international normalized ratio; aPTT, activated partial thromboplastin time.
Guidelines for the Early Management of Adults With Ischemic Stroke: Stroke 2007;38;1655-1711, Adams, et al.; originally published online Apr 12, 2007.