Wells P S, Lensing A W, Davidson B L, Prins M H, Hirsh J
Ottawa Civic Hospital, Ontario, Canada.
Ann Intern Med. 1995 Jan 1;122(1):47-53. doi: 10.7326/0003-4819-122-1-199501010-00008.
To evaluate, by meta-analysis, the accuracy of ultrasound screening for deep venous thrombosis in patients after orthopedic surgery.
The MEDLINE database from January 1982 to October 1993. Bibliographies of retrieved articles and recent journal publications were searched independently and using Current Contents.
All articles evaluating the use of venous ultrasound imaging (B-mode, duplex, and color Doppler) compared with standard contrast venography for detecting deep venous thrombosis. We excluded abstracts, early reports of studies later reported in full, and studies in which venography was not done in all patients. Seventeen of 30 identified studies were eligible.
Eligible articles were reviewed for the presence of three key criteria necessary for evaluating the accuracy of the diagnostic tests: 1) previously established objective criteria for venography and ultrasound, 2) independent blinded comparisons of venography and ultrasound, and 3) prospective evaluations of consecutive patients. Studies including all three key criteria were defined as level 1 (minimized bias) studies; otherwise, they were defined as level 2 studies.
In level 1 studies, ultrasonography had a sensitivity of 62% (95 of 153; 95% CI, 54% to 70%), a specificity of 97% (CI, 96% to 98%), and a positive predictive value of 66% (95 of 144; CI, 58% to 74%) for detecting proximal thrombi. For level 2 studies, the sensitivity was 95% (CI, 87% to 99%), the specificity was 100% (CI, 99% to 100%), and the positive predictive value was 100% (CI, 94% to 100%). Differences between level 1 and level 2 studies appeared to be related to bias in study design.
Venous ultrasound imaging has only moderate sensitivity and a moderate positive predictive value when used to screen for deep venous thrombosis in patients after orthopedic surgery; thus, ultrasound imaging may have limitations as a screening test.
通过荟萃分析评估超声筛查骨科手术后患者深静脉血栓形成的准确性。
1982年1月至1993年10月的MEDLINE数据库。独立检索所获文章的参考文献以及近期期刊出版物，并使用《现刊目次》进行检索。
所有评估静脉超声成像（B型、双功和彩色多普勒）与标准静脉造影术相比检测深静脉血栓形成的文章。我们排除了摘要、后来全文发表的研究的早期报告以及并非对所有患者都进行静脉造影的研究。在30项已识别的研究中，有17项符合条件。
对符合条件的文章进行审查，看是否存在评估诊断试验准确性所需的三个关键标准：1）先前确立的静脉造影和超声的客观标准，2）静脉造影和超声的独立盲法比较，3）对连续患者的前瞻性评估。包括所有三个关键标准的研究被定义为1级（偏差最小化）研究；否则，它们被定义为2级研究。
在1级研究中，超声检查对检测近端血栓的敏感性为62%（153例中的95例；95%可信区间，54%至70%），特异性为97%（可信区间，96%至98%），阳性预测值为66%（144例中的95例；可信区间，58%至74%）。对于2级研究，敏感性为95%（可信区间，87%至99%），特异性为100%（可信区间，99%至100%），阳性预测值为100%（可信区间，94%至100%）。1级和2级研究之间的差异似乎与研究设计中的偏差有关。
静脉超声成像用于筛查骨科手术后患者的深静脉血栓形成时，敏感性和阳性预测值均中等；因此，超声成像作为一种筛查试验可能存在局限性。
