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KEY POINTS
■ Effective interventions are available for acute large-vessel ischemic stroke, but only 2.4% of stroke patients receive them. All must be delivered within 3 to 8 hours of symptom onset, with the shortest time to recanalization and thus reperfusion being the strongest determinant of a good outcome.
■ The primary advantage of IV rtPA is the relative ease and rapidity of administration. However, IV administration of rtPA has the disadvantage of introducing a large dose systemically, which increases the risk of unwanted bleeding.
■ Intra-arterial (IA) rtPA delivers a much smaller dose (2-4 mg) directly to the site of occlusion, reducing the systemic effects of IV administration, and it can be used within 6 hours of symptom onset. However, IA rtPA takes more time and more specialized resources to administer than IV rtPA.
■ Two mechanical clot extraction devices are also available for treating this type of stroke.
Stroke is the third leading cause of death and the first leading cause of disability in the United States. Approximately 795,000 new cases of stroke occur each year.
1 Stroke is broadly divided into ischemic and hemorrhagic types. Ischemic stroke accounts for 87% of all strokes.
1 Nearly half of these are caused by the sudden blockage of a large cerebral vessel.
2 Acute ischemic stroke caused by a large-vessel occlusion carries a worse prognosis than small-vessel ischemic stroke, in terms of both death rate and long-term recovery.
2
Onset of stroke is often sudden and dramatic. Patients may present with focal signs, such as arm weakness, facial droop, or slurred speech. The American Heart Association (AHA) has launched a public education campaign emphasizing the importance of quick recognition and treatment of stroke. This is because with the treatments available today, time matters.
If a blocked cerebral artery is reopened soon enough, stroke and symptom progression may be halted or even reversed. Despite campaigns for both public and professional awareness, less than 2.4% of patients suffering a large-vessel ischemic stroke receive intervention treatments that are available to reopen the blocked vessel.3
This article reviews the major treatments for large-vessel ischemic stroke, including IV recombinant tissue plasminogen activator (rtPA), intra-arterial (IA) rtPA, and mechanical clot retrieval. All these treatments must be used during the first "golden hours" following symptom onset, when cerebral artery recanalization may have great effect in reducing morbidity and mortality.
CASE REPORT
At 4:30 pm, a 37-year-old woman was sitting on the couch at a friend's house when she suddenly developed garbled speech and left-sided weakness. The patient was brought to a nearby hospital, where her medical history was carefully reviewed. There had been no recent surgery, trauma, or anticoagulation. Vital signs remained stable. Laboratory studies were ordered. Noncontrast CT revealed no intracranial hemorrhage. A teleconference with a major university hospital was called. The patient was assigned a National Institutes of Health Stroke Scale (NIHSS) score of 17.
At 5:30 pm, the patient was given 70 mg of IV rtPA (0.9 mg/kg). She was then transported via helicopter to the university hospital. At arrival, her NIHSS remained stable at 17. CT arteriography revealed an abrupt cutoff of the right middle cerebral artery, as well as hypodensity in the temporal and parietal lobes suspicious for an evolving right middle cerebral artery (MCA) stroke.
The patient was brought to the neurointervention suite for further evaluation and treatment. Cerebral angiography confirmed the CT arteriography finding of proximal right MCA blockage (Figure 1). At 8:30 pm, 4 mg of rtPA was injected directly into the clot via an intra-arterial microcatheter. At 9:00 pm, a MERCI Retriever device was deployed, and the right MCA was opened after just one pass (Figure 2). The next day, an echocardiogram revealed a previously undiscovered patent foramen ovale (PFO). Although no deep venous thrombosis was found, it was possible that a clot had traveled from the venous system through the PFO and into the brain to occlude the artery.
Timely diagnosis, response, and intervention resulted in a good outcome for this patient. Three days after presenting to the hospital with aphasia and hemiparesis, she was discharged home with only minor residual symptoms. She was placed on anticoagulation therapy and referred to cardiology for repair of the PFO.