Review: Graduated compression stockings prevent postoperative deep venous thrombosis
ACP J Club. 1994 July-Aug;121:8. doi:10.7326/ACPJC-1994-121-1-008
Wells PS, Lensing AW, Hirsh J. Graduated compression stockings in the prevention of postoperative venous thromboembolism. A meta-analysis. Arch Intern Med. 1994 Jan 10;154:67-72.
To determine the effectiveness of graduated compression stockings in the prevention of postoperative deep venous thrombosis (DVT) using meta-analysis.
Studies in all languages were identified by MEDLINE (1966 to June 1992) using the medical subject headings clothing, bandages, thromboembolism, thrombophlebitis, and postoperative complications; Current Contents; and bibliographies of relevant papers.
Studies were selected if the use of graduated compression stockings for the prophylaxis of venous thromboembolism was assessed; the compression stocking group was compared with an untreated or unconfounded control group; proper randomization was used; reliable objective tests with proven accuracy for the diagnosis of postoperative DVT were used, specifically venography or fibrinogen I-125 leg scanning; interpretation of venography was independent and blinded; and interpretation of fibrinogen I-125 scanning was based on predefined criteria.
Through independent review by at least 2 of the authors, data on type of surgery, diagnostic test used, and rate of DVT in patients in the graduated compression stocking group and the control group were extracted. The data for orthopedic surgery were analyzed separately.
12 of 122 identified studies met the selection criteria. 11 of the 12 studies were in patients who had moderate-risk nonorthopedic surgery (i.e., abdominal, gynecologic, and neurosurgery). In these 11 studies involving 1752 patients, fewer patients in the graduated compression stocking group developed postoperative DVT compared with those in the control group (Table). The only study of patients who had orthopedic surgery was for total hip replacement. DVT occurred in 13 of the 44 patients treated with graduated compression stockings compared with 21 of the 46 control patients. 3 of the 12 studies reported on pulmonary embolism and suggested that graduated compression stockings may result in a risk reduction for this outcome.
The use of graduated compression stockings for prophylaxis of deep venous thrombosis after moderate-risk surgery is effective. No conclusions can be reached about the effectiveness of stockings after orthopedic surgery because only 1 study used sound methods.
Source of funding: Not stated.
For article reprint: Not available.
Table. Graduated compression stockings (GCS) vs control treatment in patients having surgery (length of follow-up not reported)*
|Outcome||Weighted event rates||RRR (95% CI)||NNT (CI)|
|Postoperative deep venous thrombosis||9%||18%||61% (48 to 70)||11 (8 to 18)|
*Abbreviations defined in Glossary; RRR, NNT, and CI calculated from data in article.
Graduated compression stockings are simple to use and free of complications. The meta-analysis by Wells and colleagues provides a useful, structured review of an otherwise unwieldy literature and confirms, surprisingly perhaps, that stockings are quite effective.
The authors used reasonable methodologic criteria to select 12 of 122 eligible articles, including 35 randomized trials, that were most likely to be free of bias. The selected studies provided a broad spectrum of patients at moderate-to-high risk for postoperative DVT. 5 studies compared stockings with placebo; the others used additional prophylaxis in the stocking and control groups. In 7 of the studies, ≥ 20% of the patients had surgery for malignant neoplasms. Conclusions about patients who had orthopedic surgery or about prevention of pulmonary embolism could not be reached. 5 of the 11 studies of patients who had nonorthopedic surgery included those treated with only 1 stocking, with a study leg and a control leg. Exclusion of these studies did not affect the conclusion of the review. Having selected the best studies, the authors were able to extend the power of the available data to estimate a DVT risk reduction of 61% with considerable confidence.
It appears that graduated compression stockings prevent DVT in patients at moderate risk after surgery. It is not clear whether compression stockings in conjunction with other means of prophylaxis would be more effective than compression stockings alone. Because stockings are easy to use, inexpensive, and free of complications, they should be more widely used. For patients at higher risk (e.g., those who have abdominal or pelvic surgery for cancer), graded compression stockings in conjunction with standard anticoagulant prophylaxis (e.g., low-dose heparin) offer hope for even more effective prevention of DVT. Further studies of prophylactic combinations in high-risk settings such as orthopedic or cancer surgery are indicated.
Daniel M. Becker, MD, MPH
University of Virginia School of MedicineCharlottesville, Virginia, USA