Systematic review and meta-analysis of the diagnostic accuracy of ultrasonography for deep vein thrombosis

Background Ultrasound (US) has largely replaced contrast venography as the definitive diagnostic test for deep vein thrombosis (DVT). We aimed to derive a definitive estimate of the diagnostic accuracy of US for clinically suspected DVT and identify study-level factors that might predict accuracy. Methods We undertook a systematic review, meta-analysis and meta-regression of diagnostic cohort studies that compared US to contrast venography in patients with suspected DVT. We searched Medline, EMBASE, CINAHL, Web of Science, Cochrane Database of Systematic Reviews, Cochrane Controlled Trials Register, Database of Reviews of Effectiveness, the ACP Journal Club, and citation lists (1966 to April 2004). Random effects meta-analysis was used to derive pooled estimates of sensitivity and specificity. Random effects meta-regression was used to identify study-level covariates that predicted diagnostic performance. Results We identified 100 cohorts comparing US to venography in patients with suspected DVT. Overall sensitivity for proximal DVT (95% confidence interval) was 94.2% (93.2 to 95.0), for distal DVT was 63.5% (59.8 to 67.0), and specificity was 93.8% (93.1 to 94.4). Duplex US had pooled sensitivity of 96.5% (95.1 to 97.6) for proximal DVT, 71.2% (64.6 to 77.2) for distal DVT and specificity of 94.0% (92.8 to 95.1). Triplex US had pooled sensitivity of 96.4% (94.4 to 97.1%) for proximal DVT, 75.2% (67.7 to 81.6) for distal DVT and specificity of 94.3% (92.5 to 95.8). Compression US alone had pooled sensitivity of 93.8 % (92.0 to 95.3%) for proximal DVT, 56.8% (49.0 to 66.4) for distal DVT and specificity of 97.8% (97.0 to 98.4). Sensitivity was higher in more recently published studies and in cohorts with higher prevalence of DVT and more proximal DVT, and was lower in cohorts that reported interpretation by a radiologist. Specificity was higher in cohorts that excluded patients with previous DVT. No studies were identified that compared repeat US to venography in all patients. Repeat US appears to have a positive yield of 1.3%, with 89% of these being confirmed by venography. Conclusion Combined colour-doppler US techniques have optimal sensitivity, while compression US has optimal specificity for DVT. However, all estimates are subject to substantial unexplained heterogeneity. The role of repeat scanning is very uncertain and based upon limited data

Acute Branch Retinal Arterial Embolism Succefffully Treateted with Intravenous Prostaglandin E1.

The purpose of this paper is to report the use of intravenous prostaglandin E1, a potent vasodilator, to rapidly restore blood flow and vision in a patient with an acute branch retinal arterial occlusion. An 82-year-old woman with an acute decrease in the visual acuity of her left eye due to an acute superior temporal branch retinal arterial embolus was treated with 140 microg of intravenous prostaglandin E1. The medicine was repeated the following day. At the onset of the branch arterial occlusion her vision in the left eye was 20/50, the embolus could be seen in the superior temporal branch, and a white retinal edema extended down into the macula. At her first eye examination 4 days after treatment, her visual acuity had returned to 20/20, the retinal embolus was still present, but the white macular edema had disappeared. Intravenous prostaglandin E1 is a safe, potent vasodilator for the peripheral vascular system. If used immediately to treat acute branch arterial retinal occlusions, it can restore good vision. The authors report the first case of the use of intravenous prostaglandin E1 to treat a spontaneous acute branch retinal arterial embolus