Incidence and prevention of deep venous thrombosis occurring late after general surgery: randomised controlled study of prolonged thromboprophylaxis. Electrostimulation for the prevention of deep venous thrombosis in patients with major trauma: a prospective randomized study. Prevention of postoperative deep venous thrombosis and pulmonary emboli with combined modalities. Prolonged thromboprophylaxis with Dalteparin during immobilization after ankle fracture surgery: a randomized placebo-controlled, double-blind study. Prevention of postoperative deep vein thrombosis in cancer patients. A randomized trial with low molecular weight heparin (CY 216). A randomized, prospective trial of deep venous thrombosis prophylaxis in aortic surgery. Venous thromboembolism prophylaxis after head and spinal trauma: intermittent pneumatic compression devices versus low molecular weight heparin. Low dose heparin and compression stockings in the prevention of postoperative deep venous thrombosis. The efficacy of pneumatic compression stockings in the prevention of pulmonary embolism after cardiac surgery.
To study the incidence of late deep venous thrombosis (DVT), and to evaluate a regimen of prolonged thromboprophylaxis after general surgery.
                Randomised, controlled, open trial, with blinded evaluation.
                University hospital, Denmark.
                176 consecutive patients undergoing major elective abdominal or non-cardiac thoracic operations, of whom 118 were eligible for evaluation.
                Thromboprophylaxis with a low-molecular-weight heparin, tinzaparin, given for four weeks (n = 58), compared with one week (control group, n = 60).
                Presence of DVT established by bilateral venography four weeks after the operation.
                The incidence of late DVT in the control group was 6/60 (10%, 95% confidence interval (CI) 4% to 21%). In the prophylaxis group it was 3/58 (5.2%, 95% CI 1% to 14%) (p = 0.49).
                Prolonged thromboprophylaxis had no significant effect on the incidence of DVT occurring late after general surgery. Current methods of posttraumatic thromboprophylaxis (heparins and sequential compression devices) are inadequate. New methods should be tested. Muscle electrostimulation (MEST) has been used over the years with mixed-but predominantly encouraging-results for a variety of conditions, including prevention of deep venous thrombosis (DVT). It has not been tested in multiple trauma patients.
                Trauma patients with Injury Severity Score higher than 9 who were admitted to the intensive care unit and had a contraindication for prophylactic heparinization were randomized to groups MEST and control. MEST patients received 30-minute MEST sessions twice daily for 7 to 14 days. Venous flow velocity and venous diameter were measured by duplex venous scan. Venography-or, if not available, duplex-was used to evaluate the presence of proximal and peripheral DVT between days 7 and 15.
                After exclusions, 26 MEST and 21 control patients completed the study and received outcome evaluation by venography (25) or duplex (22). Three patients in each group developed proximal DVT (11.5% vs 14%, P = .79), and an additional 4 (15%) MEST group and 3 (14%) control group patients developed peripheral DVT ( P = .96). There was no difference in venous flow velocity or venous diameter between the groups.
                MEST was not effective in decreasing DVT rates in major trauma patients. Worldwide statistics reveal that 25 to 40 per cent of patients who are over the age of 40 years and operated on for 1 or more hours will develop a deep venous thrombosis (DVT). The studies reviewed in this paper were performed to evaluate several modalities and compare their effectiveness in preventing DVT in postoperative patients. In the first study, five modalities plus a control group were evaluated in 562 patients from five surgical specialties. The incidence of DVT in the control group was 35 per cent. Though most of the pharmacologic agents were effective in reducing the incidence of DVT, the antistasis devices (gradient elastic stockings and intermittent pneumatic compression) were most effective. The purpose of the second study was to evaluate the effectiveness of combining a pharmacologic drug with an antistasis modality. Deep venous thrombosis was virtually eliminated in this group of 328 patients. There was only a 1.5 per cent incidence of DVT in the treated population as compared to a 26.8 per cent incidence in the control group. Thus, it seems that combining one antistasis and one pharmacologic agent greatly reduces the incidence of lower extremity thrombi. I-125 fibrinogen scanning was the most sensitive test in detecting DVT and had an accuracy of 97 per cent. Skeletal trauma and immobilization are well-known risk factors for deep vein thrombosis (DVT) and pulmonary embolism (PE). While prophylaxis against thromboembolic complications has become routine after major orthopedic surgery, whether or not prophylaxis after minor surgery and lower limb immobilization is necessary is still under debate.
                In a double-blind, placebo-controlled study, 272 consecutive patients were randomized to receive either thromboprophylaxis with Dalteparin (n = 136) or placebo (n = 136) for 5 weeks after ankle fracture surgery. All patients received 1 week of initial treatment with Dalteparin before randomization. A unilateral phlebography was performed when the cast was removed.
                The overall incidence of DVT was 21% (95% CI: 13-29%) in the Dalteparin group and 28% (CI: 19- 37%) in the placebo group (risk ratio = 0.8, CI: 0.6-1.1; p = 0.3). The incidence of proximal DVTs was 4% and 3%, respectively. No major bleeding occurred.
                We found no significant difference in the incidence of DVT between the 2 treatment groups and our results do not support prolonged thromboprophylaxis. The overall incidence of DVT was high, reflecting the potential risk of PE and post-thrombotic syndrome after ankle fracture surgery. Most of the DVTs were asymptomatic, however, and were located in distal veins. Sixty-one consecutive patients were enrolled in a randomized, controlled trial of thromboprophylaxis with a low molecular weight heparin (Seleparina, CY 216) in major abdominal oncological surgery. Thirty patients received 2 x 3,825 anti-Xa international units of CY 216 subcutaneously on the day of surgery followed by a single daily 3,825 anti-Xa international units injection for 7 days; thirty-one patients did not receive any form of prophylaxis. The occurrence of deep vein thrombosis (DVT) was detected by 125I-labelled fibrinogen leg scan. Postoperative DVT developed in 2 patients in the CY 216 group and in 11 patients in the control group (6.8% vs 35.4%, p < 0.01). Although there was a higher postoperative transfusional requirement in the group receiving CY216 (p < 0.05), the total number of patients transfused was similar in the two groups (14 vs 13). On day 1 after surgery, the two patients who later developed DVT in the CY216 group had plasma anti-Xa activity significantly lower (p < 0.01) than the remaining patients. As a good relationship was found between plasma anti-Xa activity and body weight, adoption of a personalized dosage schedule might improve efficacy of CY 216 prophylaxis. To study the incidence of postoperative deep venous thrombosis (DVT) in patients undergoing elective aortic reconstruction and to determine if aggressive DVT prophylaxis would reduce the incidence of DVT in these patients.
                Randomized, prospective trial.
                University hospital and Veterans Affairs hospital.
                One hundred patients undergoing aortic reconstruction for aneurysmal or occlusive disease randomized to receive DVT prophylaxis (treatment group) or no prophylaxis (control group). Exclusion criteria included a history of DVT, long-term anticoagulant use, or a malignant neoplasm. During the study period, 12 patients were ineligible for follow-up. Ninety-eight patients completed the trial, including 50 patients in the treatment group and 48 patients in the control group. Two patients in the control group died postoperatively of unrelated causes.
                Patients in the treatment group received DVT prophylaxis using a combination of low-dose heparin sodium therapy (5000 U every 12 hours) and calf-length intermittent mechanical compression devices. Control patients received no DVT prophylaxis.
                The occurrence of acute lower extremity DVT diagnosed by interval venous duplex ultrasound scan surveillance performed on postoperative days 1, 3, and 7.
                The overall incidence of proximal DVT in this study was 2%. One case of DVT occurred in the treatment group, and the other one occurred in the control group. There was no statistically significant difference (P = .99) in the incidence of DVT between the 2 groups. One patients in the control group had a nonfatal pulmonary embolus (1% of the patients overall).
                The incidence of proximal DVT in patients undergoing elective aortic reconstruction is low compared with patients undergoing other major intraabdominal general surgical procedures. The use of aggressive DVT prophylaxis did not reduce the risk of postoperative proximal DVT in this study. The selective use of DVT prophylaxis in patients undergoing elective aortic surgery should be based on associated concomitant or evolving risk factors. Although there are alternative methods and drugs for preventing venous thromboembolism (VTE), it is not clear which modality is most suitable and efficacious for patients with severe (stable or unstable) head/spinal injures. The aim of this study was to compare intermittent pneumatic compression devices (IPC) with low-molecular-weight heparin (LMWH) for preventing VTE. We prospectively randomized 120 head/spinal traumatized patients for comparison of IPC with LMWH as a prophylaxis modality against VTE. Venous duplex color-flow Doppler sonography of the lower extremities was performed each week of hospitalization and 1 week after discharge. When there was a suspicion of pulmonary embolism (PE), patients were evaluated with spiral computed tomography. Patients were analyzed for demographic features, injury severity scores, associated injuries, type of head/spinal trauma, complications, transfusion, and incidence of deep venous thrombosis (DVT) and PE. Two patients (3.33%) from the IPC group and 4 patients (6.66%) from the LMWH group died, with their deaths due to PE. Nine other patients also succumbed, unrelated to PE. DVT developed in 4 patients (6.66%) in the IPC group and in 3 patients (5%) in the LMWH group. There was no statistically significant difference regarding a reduction in DVT, PE, or mortality between groups ( p = 0.04, p > 0.05, p > 0.05, respectively). IPC can be used safely for prophylaxis of VTE in head/spinal trauma patients. The frequency of deep venous thrombosis (DVT) was studied in 98 patients undergoing major abdominal surgery. All the patients received low dose heparin prophylaxis 5000 i.u. every 12 h for 5-7 days. In each patient, a graduated compression stocking was also worn and randomly allocated to one of the legs and the other leg served as a control. DVT was diagnosed by the 125I-fibrinogen method. Four patients developed bilateral DVT and 8 patients unilateral DVT, all of whom developed it in the control leg. The difference in unilateral DVT between stockinged and control legs was significant (P < 0.004). It is concluded that a combination of low dose heparin and graduated compression stockings is more effective than low dose heparin alone in reducing the frequency of postoperative DVT. It is suggested that this combination of prophylaxis might be of value in high risk patients. Pneumatic compression stocking (PCS) devices have been introduced to decrease the incidence of postoperative deep venous thrombosis (DVT). However, their role in the prophylaxis against pulmonary embolism (PE) remains unclear. This study was undertaken to compare the prophylactic effectiveness of subcutaneous heparin (SCH) alone vs the combined use of PCS and SCH in the prevention of PE following cardiac surgery.
                We studied 2,551 consecutive patients who underwent cardiac surgery over a 10-year period. They were randomly allocated to two groups. Group A included 1,196 patients who were treated with 5,000 U of SCH every 12 h and group B included 1,355 patients treated with a combined prophylactic regimen of PCS and SCH.
                The diagnosis of PE was established in 69 patients by either high-probability ventilation perfusion scan, pulmonary angiogram, or autopsy. The incidence of PE in group A patients was 4% (48/1,196) and in group B was 1.5% (21/1,355). The concomitant use of bilateral PCS and SCH reduced the frequency of postoperative PE in 62% in comparison to the prophylaxis with SCH alone (p < 0.001).
                These data suggest that the combined prophylactic method of bilateral PCS and SCH is superior to SCH alone in the prevention of PE after cardiac surgery.
We did not find evidence that thromboprophylaxis reduces mortality or PE in any of the comparisons assessed. However, we found some evidence that thromboprophylaxis prevents DVT. Although the strength of the evidence was not high, taking into account existing information from other related conditions such as surgery, we recommend the use of any DVT prophylactic method for people with severe trauma.