BACKGROUND:A pre-test probability score and D-dimer may reduce the need for ultrasound examinations for excluding lower limb deep venous thrombosis (DVT).OBJECTIVE:To establish the accuracy of an immunochromatographic D-dimer assay called 'Simplify' for diagnosis of acute DVT by complete (calf veins included) lower limb ultrasound examination.METHODS:A total of 453 consecutive patients presented to the ED of a tertiary centre with suspected first episode of DVT, were prospectively recruited. A pre-test probability score (Hamilton Score), an immunochromatographic D-dimer and a complete, single, unilateral lower limb ultrasound examination were performed in all patients. All patients with a negative ultrasound examination were followed up for 3 months.RESULTS:There were 159 men and 294 women with a mean age of 55.8 years (SD 20.3). Of the 227 patients with a negative D-dimer, 214 patients had negative ultrasound examinations and 13 patients had isolated calf DVT. Among the 226 patients with a positive D-dimer, 74 patients had DVT and 152 patients had negative ultrasound examinations. The sensitivity, specificity, positive and negative predictive values were 85.1% (75.8-91.8), 58.5% (53.4-63.5), 32.7% (26.6-38.9) and 94.3% (90.4-96.9), respectively. One hundred and sixty-five patients had an unlikely Hamilton Score and a negative D-dimer. The negative predictive value of the immunochromatographic D-dimer in an unlikely Hamilton Score population was 98.8% (95.7-99.8%).CONCLUSION:An unlikely probability Hamilton Score and a negative immunochromatographic D-dimer reliably exclude both proximal and isolated calf DVT.

Background and Purpose —Abnormalities in endogenous fibrinolysis are associated with an increased risk for stroke in men and older adults. We tested the hypothesis that elevated plasma tissue plasminogen activator (tPA) antigen, a marker for impaired endogenous fibrinolysis, is an independent risk factor for stroke in young women. Methods —Subjects were 59 nondiabetic females ages 15 to 44 years with cerebral infarction from the Baltimore-Washington area and 97 control subjects frequency-matched for age who were recruited by random-digit dialing from the same geographic area. A history of cerebrovascular disease risk factors was obtained by face-to-face interview. Plasma tPA antigen was measured by enzyme-linked immunosorbent assay. Results —Mean plasma tPA antigen levels were significantly higher in stroke patients than control subjects (4.80±4.18 versus 3.23±3.67 ng/mL; P =0.015). After adjustment for age, hypertension, cigarette smoking, body mass index, and ischemic heart disease, there was a dose-response association between tPA antigen and stroke with a 3.9-fold odds ratio of stroke (95% CI, 1.2 to 12.4; P =0.03) for the upper quartile (>4.9 ng/mL) of tPA antigen compared with the lowest quartile. The dose-response relationship between tPA antigen and stroke was equally present in white and nonwhite women, and further adjustment for total and HDL cholesterol levels only modestly attenuated this association. Conclusions —This population-based case-control study shows that elevated plasma tPA antigen level is independently associated with an increased risk for ischemic stroke in nondiabetic females 15 to 44 years of age. These findings support the hypothesis that impaired endogenous fibrinolysis is an important risk factor for stroke in young women.

BACKGROUND AND PURPOSE:Abnormalities in endogenous fibrinolysis are associated with an increased risk for stroke in men and older adults. We tested the hypothesis that elevated plasma tissue plasminogen activator (tPA) antigen, a marker for impaired endogenous fibrinolysis, is an independent risk factor for stroke in young women.METHODS:Subjects were 59 nondiabetic females ages 15 to 44 years with cerebral infarction from the Baltimore-Washington area and 97 control subjects frequency-matched for age who were recruited by random-digit dialing from the same geographic area. A history of cerebrovascular disease risk factors was obtained by face-to-face interview. Plasma tPA antigen was measured by enzyme-linked immunosorbent assay.RESULTS:Mean plasma tPA antigen levels were significantly higher in stroke patients than control subjects (4. 80+/-4.18 versus 3.23+/-3.67 ng/mL; P=0.015). After adjustment for age, hypertension, cigarette smoking, body mass index, and ischemic heart disease, there was a dose-response association between tPA antigen and stroke with a 3.9-fold odds ratio of stroke (95% CI, 1.2 to 12.4; P=0.03) for the upper quartile (>4.9 ng/mL) of tPA antigen compared with the lowest quartile. The dose-response relationship between tPA antigen and stroke was equally present in white and nonwhite women, and further adjustment for total and HDL cholesterol levels only modestly attenuated this association.CONCLUSIONS:This population-based case-control study shows that elevated plasma tPA antigen level is independently associated with an increased risk for ischemic stroke in nondiabetic females 15 to 44 years of age. These findings support the hypothesis that impaired endogenous fibrinolysis is an important risk factor for stroke in young women.

Background and Purpose-Activation of plasma protein C (PC) zymogen by thrombin-thrombomodulin at the endothelial surface is an important endogenous antithrombotic mechanism. It is unknown whether activated protein C (APC) is generated in vivo in the cerebrovasculature, because there is only Limited thrombomodulin expression in human brain vascular endothelium. Therefore, we tested the hypothesis that carotid occlusion produces brain-specific PC activation.Methods-Blood samples were simultaneously collected from the ipsilateral internal jugular vein and radial artery before and during carotid cross-clamping and on "de-occlusion" in 8 awake patients undergoing routine carotid endarterectomy. Plasma PC zymogen and circulating APC levels were measured using enzyme immunocapture assay and expressed as percent of pooled plasma controls.Results-Internal jugular vein APC levels increased 28% exclusively during carotid occlusion and then decreased 32% with de-occlusion (F=8.1, P<0.005). PC zymogen increased only 5.9% with occlusion (F=6.3, P<0.02), consistent with hemoconcentration. There were no changes in radial artery PC or APC levels.Conclusions-These findings demonstrate brain-specific protein C activation in humans during carotid occlusion and suggest a protective role for endogenous APC generation during cerebrovascular occlusion.

Copyright © 1999 American Heart Association. All rights reserved. Print ISSN: 0039-2499. Online Stroke is published by the American Heart Association. 7272 Greenville Avenue, Dallas, TX 72514 1999;30;7-11 Stroke Buchholz and Paul D. Stolley R. Price, Robert J. McCarter, Constance J. Johnson, Christopher J. Earley, David W. Thomas Wozniak, Robert J. Wityk, Barney J. Stern, Michael A. Sloan, Roger Sherwin, Richard F. Macko, Steven J. Kittner, Anne Epstein, D. Kim Cox, Marcella A. Prevention in Young Women Study Elevated Tissue Plasminogen Activator Antigen and Stroke Risk : The Stroke http://stroke.ahajournals.org/cgi/content/full/30/1/7 located on the World Wide Web at: The online version of this article, along with updated information and services, is