Background and Purpose -To evaluate duplex ultrasonographic thresholds for the determination of 70%to 99%stenosis of the ipsilateral and contralateral internal carotid artery in patients with symptoms of amaurosis fug...Background and Purpose -To evaluate duplex ultrasonographic thresholds for the determination of 70%to 99%stenosis of the ipsilateral and contralateral internal carotid artery in patients with symptoms of amaurosis fugax, transient ischemic attack (TIA), or minor stroke based on 2 criteria: maximizing accuracy and optimizing cost-effectiv- eness and to compare these with current recommendations. Methods -From January 1997 to January 2000, a prospective multicenter study was conducted including 350 consecutive patients with symptoms of amaurosis fugax, TIA, or minor stroke who underwent bilateral duplex ultrasonography and digital subtraction angiograp hy. A linear regression analysis was performed to estimate the degree of angiogr aphic stenosis as a function of the peak systolic velocity (PSV). PSV thresholds were calculated for the ipsilateral and contralateral carotid arteries based on maximizing accuracy and optimizing cost-effectiveness. Results -The PSV measu rements significantly overestimated the angiographic stenosis in the contralater al artery (9.5%; 95%CI, 6.3%to 12.7%) compared with the ipsilateral carotid artery. The recommended PSV threshold for the diagnosis of 70%to 99%stenosis i s 230 cm/s. Maximizing accuracy, the optimal PSV threshold for the ipsilateral a rtery was 280 cm/s, and for the contralateral artery, 370 cm/s for diagnosing a 70%to 99%stenosis. Optimizing cost-effectiveness, the optimal PSV threshold was 220 cm/s for ipsilateral and 290 cm/s for contralateral carotid arteries. Conclusions -PSV measurements overestimate the degree of angiographic stenosis in the contralateral carotid artery in patients with symptoms of amaurosis fugax, TIA, or minor stroke. Separate PSV thresholds should be used for the ipsilateral and contralateral carotid artery. PSV thresholds that optimize cost-effectiveness differ from the recommended thresholds and from thresholds that maximize accuracy.展开更多
文摘Background and Purpose -To evaluate duplex ultrasonographic thresholds for the determination of 70%to 99%stenosis of the ipsilateral and contralateral internal carotid artery in patients with symptoms of amaurosis fugax, transient ischemic attack (TIA), or minor stroke based on 2 criteria: maximizing accuracy and optimizing cost-effectiv- eness and to compare these with current recommendations. Methods -From January 1997 to January 2000, a prospective multicenter study was conducted including 350 consecutive patients with symptoms of amaurosis fugax, TIA, or minor stroke who underwent bilateral duplex ultrasonography and digital subtraction angiograp hy. A linear regression analysis was performed to estimate the degree of angiogr aphic stenosis as a function of the peak systolic velocity (PSV). PSV thresholds were calculated for the ipsilateral and contralateral carotid arteries based on maximizing accuracy and optimizing cost-effectiveness. Results -The PSV measu rements significantly overestimated the angiographic stenosis in the contralater al artery (9.5%; 95%CI, 6.3%to 12.7%) compared with the ipsilateral carotid artery. The recommended PSV threshold for the diagnosis of 70%to 99%stenosis i s 230 cm/s. Maximizing accuracy, the optimal PSV threshold for the ipsilateral a rtery was 280 cm/s, and for the contralateral artery, 370 cm/s for diagnosing a 70%to 99%stenosis. Optimizing cost-effectiveness, the optimal PSV threshold was 220 cm/s for ipsilateral and 290 cm/s for contralateral carotid arteries. Conclusions -PSV measurements overestimate the degree of angiographic stenosis in the contralateral carotid artery in patients with symptoms of amaurosis fugax, TIA, or minor stroke. Separate PSV thresholds should be used for the ipsilateral and contralateral carotid artery. PSV thresholds that optimize cost-effectiveness differ from the recommended thresholds and from thresholds that maximize accuracy.
