Deep-vein thrombosis after fracture of the pelvis: assessment with serial duplex-ultrasound screening.

Sixty patients who had had a major fracture of the pelvis and were in stable condition on the orthopaedic ward three to five days after the injury were tested serially with duplex ultrasound, beginning approximately seven days after the injury, in order to determine the incidence of deep-vein thrombosis. Contrast venography was performed to confirm all positive non-invasive studies. Deep-vein thrombosis developed in eight patients (approximately 15 per cent). The thrombosis was in the popliteal or a more proximal vein in six of the eight patients, whereas in two it was distal to the popliteal vein. In four patients, evidence of thrombosis developed after one or more normal duplex-ultrasound studies. In one patient, symptoms that were suggestive of deep-vein thrombosis developed fifty-two days after the injury (four days after the fourth normal duplex-ultrasound examination), and ascending venography was entirely normal. Another patient had a pulmonary embolus fifteen days after the injury, and on the same day a duplex-ultrasound study was positive for thrombosis. During six weeks of follow-up after discharge from the hospital, symptoms of deep-vein thrombosis or pulmonary embolism did not develop in any patient in whom serial duplex-ultrasound studies had been negative.

Diagnosis of deep-vein thrombosis using duplex ultrasound.

PURPOSE: To critically evaluate the accuracy, advantages, and drawbacks of duplex ultrasound as a diagnostic test for proximal deep-vein thrombosis. DATA IDENTIFICATION: An English-language search using MEDLINE (1980 to 1988) and bibliographies from articles, and a hand search of pertinent radiology and ultrasound journals from 1988. STUDY SELECTION: All series comparing duplex ultrasound to the reference standard, contrast venography, were reviewed and classified into levels based on the quality of study design. DATA EXTRACTION: Results of duplex ultrasound compared with venography in the proximal deep venous system, technical problems encountered, frequency of diagnosis of other causes of leg swelling, and frequency of unsuccessful or inconclusive studies were collated. RESULTS OF DATA SYNTHESIS: Four well-designed studies reported similar results. The sensitivity of duplex ultrasound in detecting proximal thrombi ranged from 92% to 95% with a combined sensitivity of 93% (CI, 88% to 98%), and the specificity ranged from 97% to 100% with a combined sensitivity of 98% (CI, 96% to 100%). Similar findings were noted in nine other studies that had minor methodologic flaws. Four studies reported that ultrasound was able to identify a nonthrombotic cause of leg swelling in 5% to 15% of cases. Four studies found that duplex ultrasound was inconclusive in 1% to 6% of cases, with a combined frequency of 2%. CONCLUSIONS: Duplex ultrasound appears to be very accurate in the detection of acute proximal deep-vein thrombosis. This test has major advantages as well as certain limitations compared with other diagnostic methods.

Treatment of proximal deep-vein thrombosis using subcutaneously administered calcium heparin: comparison with intravenous sodium heparin.

In a prospective, randomized clinical trial we compared the efficacy of subcutaneously (SC) administered (every 8 h) calcium heparin to intravenous (IV) sodium heparin in the treatment of proximal deep-vein thrombosis (DVT). A secondary objective was to give enough heparin to achieve a therapeutic anticoagulant effect by the end of the first 24 h. Five of 36 patients (14%) in the SC heparin group failed to achieve a therapeutic anticoagulant effect by the end of the first 24 h compared to 2 of 23 patients (9%) in the IV group (p = NS; 95% CI for true difference = -11.7% to 22.1%). Two of 31 patients (6.5%) in the SC group had venographic evidence of clot propagation compared to 1 of 19 patients (5.3%) in the IV group (p = NS; 95% CI for true difference = -12.4% to 14.8%). The rate of major hemorrhagic complications was similar in each group (approximately 15%). We conclude: (1) using a large initial dose of SC heparin, a therapeutic anticoagulant effect can be readily achieved within 24 h, and (2) combining the results of this trial with previous studies, the efficacy of SC administered calcium appears to be comparable to IV sodium heparin.

Initiation of warfarin therapy: comparison of physician dosing with computer-assisted dosing.

In a prospective, randomized study at two university hospitals, the authors examined how effectively housestaff physicians (n = 36) managed the initiation of warfarin therapy compared with a computer-assisted dosing regimen (n = 39) using the software program Warfcalc, which was managed by one of the authors. Target prothrombin time ratios were selected by the physicians. Study endpoints included: the time to reach a therapeutic prothrombin ratio, the time to reach a stable therapeutic dose, the number of patients transiently overanticoagulated, the number of bleeding complications, and the accuracy of the predicted maintenance dose, which was assessed at steady-state 10-14 days later. Computer-assisted dosing consistently out-performed the physicians: a stable therapeutic dose was achieved 3.7 days earlier (p = 0.002), fewer patients were overanticoagulated (10% versus 41%), and the predicted maintenance dose was in the therapeutic range in 85% of the computer-dosed patients versus 42% of the physician group (p less than 0.002). For physicians who did not routinely manage warfarin therapy, computer-assisted dosing improved the accuracy of dosing and shortened the time required to achieve a stable therapeutic dose.