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SAN ANTONIO, TEX—According to the American Heart Association’s 1994 guidelines, the use of intravenous (IV) heparin is “a matter of preference of the treating physician.” According to research presented at the 41st International Stroke Conference, it appears that the subsequent publication of four clinical trials that have not demonstrated any long-term benefit for patients with acute stroke (the International Stroke Trial and the Heparin in Acute Embolic Stroke Trial) or cardioembolic stroke (the Trial of ORG 10172 in Acute Stroke Treatment and the Tinzaparin in Acute Ischaemic Stroke Trial) had little effect on the prevalent inclination of neurologists in both the United States and Canada to use IV heparin in acute ischemic stroke.
Given this climate, researchers at Wayne State University and Detroit Medical Center sought to determine current usage patterns of IV heparin for patients with acute ischemic stroke by neurologists in the United States and Canada. Ahmad Al-Sadat, MD, and colleagues hypothesized that “US neurologists would utilize heparin more frequently” than their Canadian counterparts and that their inclination would be fueled in a large part by “medicolegal factors.”
FIVE VIGNETTES
The researchers surveyed 280 neurologists from the United States and 270 Canadian neurologists, presenting them with a series of vignettes for the following scenarios: stroke in evolution, atrial fibrillation–related stroke, vertebrobasilar stroke, carotid territory stroke, and multiple transient ischemic attacks (TIAs). The cohort was asked to respond with yes, no, or maybe to whether they would use IV heparin in each scenario. The effect of medicolegal factors as a potential influence on their decision was also ascertained.
A CONTINENTAL DIVIDE
Results indicated that American neurologists were significantly more likely than their Canadian counterparts to use IV heparin for patients with stroke in evolution (51% versus 33%), vertebrobasilar stroke (30% versus 8%), carotid territory stroke (31% versus 4%), and multiple TIAs (47% versus 9%). Both American and Canadian neurologists were inclined to use IV heparin for acute stroke patients with atrial fibrillation (88% and 84%, respectively).
Additionally, as Dr. Al-Sadat and colleagues suspected, medicolegal factors were at least partially responsible for this discrepancy in practice between the United States and Canada. Thirty-three percent of US neurologists surveyed stated that medicolegal considerations were at least sometimes a factor in their decision to administer IV heparin, as compared with 10% of Canadian neurologists.
Overall, the researchers concluded, IV heparin remains popular in both countries for patients with atrial fibrillation and acute ischemic stroke, persisting even in the face of the negative results of four large trials. “Further study is necessary to examine why the negative trials are not impacting neurologist behavior,” Dr. Al-Sadat remarked.
NR
—C. Justin Romano
Suggested Reading
Adams HP Jr, Brott TG, Crowell RM, et al. Guidelines for the management of patients with acute ischemic stroke. A statement for healthcare professionals from a special writing group of the Stroke Council, American Heart Association. Stroke. 1994;25:1901-1914.
Bath PM, Lindenstrom E, Boysen G, et al. Tinzaparin in acute
ischaemic stroke (TAIST): a randomised aspirin-controlled
trial. Lancet. 2001;358:702-710.
Berge E, Abdelnoor M, Nakstad PH, Sandset PM. Low molecular-weight
heparin versus aspirin in patients with acute ischaemic
stroke and atrial fibrillation: a double-blind, randomised
study. HAEST Study Group. Heparin in Acute Embolic Stroke
Trial. Lancet. 2000;355:1205-1210.
International Stroke Trial Collaborative Group. The International
Stroke Trial (IST): a randomised trial of aspirin, subcutaneous
heparin, both, or neither among 19435 patients with acute
ischaemic stroke. Lancet. 1997;349: 1569-1581.
The Publications Committee for the Trial of ORG 10172 in
Acute Stroke Treatment (TOAST) Investigators. Low molecular
weight heparinoid, ORG 10172 (danaparoid), and outcome after
acute ischemic stroke: a randomized controlled trial. JAMA.
1998;279:1265-1272.
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