US National Survey of Physician Practices for the Secondary and Tertiary Prevention of Ischemic Stroke. Medical therapy in patients with carotid artery stenosis.

BACKGROUND AND PURPOSE

Aspirin or other platelet antiaggregants and anticoagulants are commonly used in many types of patients at elevated stroke risk. However, relatively little is known concerning how practicing physicians use these medications in their patients with extracranial carotid artery stenosis. The identification of variations in practice may help to both direct specific educational efforts and guide further research.

METHODS

Between August 1993 and February 1994, we surveyed the stroke prevention practices of a stratified random sample of 2000 US physicians. The survey included clinical scenarios that probed the use of aspirin or other platelet antiaggregants and anticoagulants in symptomatic and asymptomatic patients with carotid artery stenoses of 50% to 70% or more than 70%, with and without known surgical contraindications.

RESULTS

Sixty-seven percent of those eligible completed the survey (n = 1006). More than 85% of physicians responded that they always or often prescribe aspirin or other platelet antiaggregants regardless of degree of carotid artery stenosis, symptom status, or presence of surgical contraindications. However, the reported frequency of use of these medications varied independently according to physician specialty (P = .044). In contrast, in addition to physician specialty, the reported frequency of anticoagulant use varied independently with degree of carotid artery stenosis, symptom status, and presence of surgical contraindications (P < .0001 for each variable). Fifteen percent of physicians responded that they always or often use anticoagulants for asymptomatic patients with 50% to 70% carotid artery stenosis versus 43% who reported doing so for symptomatic patients with a similar degree of stenosis (P < .001); 28% often or always prescribe anticoagulants for asymptomatic patients with more than 70% carotid artery stenosis versus 49% who do so if symptoms are present (P < .001). The odds of noninternist primary care physicians responding that they always or often use anticoagulants were more than five times higher (odds ratio, 5.32; 95% confidence interval [CI], 3.79 to 7.45) than surgical specialists. Compared with surgical specialists, the odds ratios for the use of anticoagulants were 3.65 for internists (95% CI, 2.63 to 5.06) and 1.88 (95% CI, 1.40 to 2.53) for neurologists.

CONCLUSIONS

These data show the following: (1) Aspirin or other platelet antiaggregants are used by most physicians regardless of degree of carotid artery stenosis, symptom status, or presence of surgical contraindications; (2) anticoagulants are prescribed selectively, with each of these variables influencing their use; and (3) the use of both classes of agents varies with physician specialty training.