New Data on TIAs and Stroke Prevention
Susan C. Fagan, Pharm.D., BCPS, FCCP
Review: Eliasziw M et al. Early risk of stroke after a transient ischemic attack in patients with internal carotid artery disease. CMAJ 2004; 170(7):1105-1109.
Patients who experience a transient ischemic attack (TIA), sometimes called a "mini stroke", and return to normal neurologic function within 24 hours, are often relieved that they have "dodged the bullet" associated with a major stroke. Despite its seemingly benign course, a TIA is a serious medical condition that requires prompt attention and intervention.
In this subgroup analysis from the North American Symptomatic Carotid Endarterectomy Trial (NASCET), 603 patients with a hemispheric TIA and internal carotid artery stenosis >50% were randomized to the medical arm (no surgery, just aspirin, usually). In this group, the 90-day risk of ipsilateral stroke was very high (20.1%) and much higher than a similar-sized group of patients with stroke at entry into the trial (2.3%). The highest risk was in the 48 hours after the TIA (5.5%), proving that there is urgency in the need for interventions that decrease stroke risk. Patients with TIA symptoms should seek immediate medical attention so that the cause can be found (perhaps carotid artery disease) and secondary prevention strategies can be initiated.
Read the article on the Canadian Medical Association Journal website at http://www.cmaj.ca/cgi/content/full/170/7/1105
Review: O'Rourke F et al. Current and future concepts in stroke prevention. CMAJ 2004; 170(7):1123-1133.
This article is an excellent review of the current thinking regarding prevention of stroke in patients at risk. It is particularly useful in that all of the large clinical trials that are pivotal in our understanding of the approach to stroke prevention are presented in tabular form. The authors recommend antiplatelet agents for secondary prevention of ischemic stroke except when the patient has atrial fibrillation or recent MI, where anticoagulation with warfarin is recommended. In addition, the authors present data to support blood pressure lowering (with ACE inhibitors and diuretics) and statins for secondary stroke prevention. For patients with symptomatic carotid artery disease, the importance of carotid endarterectomy is stressed although, for asymptomatic disease, aggressive medical therapy is advocated.
Read the article on the Canadian Medical Association Journal website at http://www.cmaj.ca/cgi/content/full/170/7/1123
Review: Johnston DCC, Hill MD. The patient with transient cerebral ischemia. CMAJ 2004; 170(7):1134-1137.
This article is an instructional case where a patient with a 30 minute episode of focal neurologic symptoms is evaluated to determine the best strategies for secondary stroke prevention. He has a history of hypertension and dyslipidemia. The essentials of the diagnosis, including imaging are discussed in depth. A case for clinical trials to study early intervention after TIA is made. This short paper demonstrates how to apply the content of papers #1 and #2 (above) in clinical practice.
Read the article on the Canadian Medical Association Journal website at http://www.cmaj.ca/cgi/content/full/170/7/1134