Prevention of postoperative deep venous thrombosis and pulmonary emboli with combined modalities. The efficacy of pneumatic compression stockings in the prevention of pulmonary embolism after cardiac 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. Regimen for improved effectiveness of intermittent pneumatic compression in deep venous thrombosis prophylaxis. A randomized, prospective trial of deep venous thrombosis prophylaxis in aortic surgery. Prophylaxis of deep venous thrombosis after acute abdominal operation. Deep vein thrombosis: prevention in stroke patients during rehabilitation. Prevention of venous thrombosis with small, subcutaneous doses of heparin. Efficacy of deep venous thrombosis prophylaxis in trauma patients and identification of high-risk groups.
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. 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. 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. The incidence of deep venous thrombosis (DVT) was assessed in a series of 78 patients undergoing major surgical operations to compare the prophylactic effectiveness of intermittent sequential pneumatic compression alone with the simultaneous use of graduated compression stockings and intermittent sequential pneumatic compression. The diagnosis of DVT was determined with the I-125 fibrinogen-uptake test, Doppler ultrasound, maximum venous outflow by strain-gauge plethysmography, and contrast venography. The incidence of DVT in nonstockinged legs was 9% while that in the stockinged legs was 1%. The simultaneous use of graduated elastic compression stockings and intermittent pneumatic compression is more effective than pneumatic compression alone in the prevention of postoperative DVT. 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. Two hundred and forty-five patients who underwent acute extensive abdominal operations were randomized into three regimens to achieve optimal prophylaxis of postoperative thromboembolic complications. All of the patients were screened by the 125I-fibrinogen uptake test for seven days and if the phlebographic findings were positive. Of 81 patients receiving low dose heparin, 12 had thromboembolism. Of 79 receiving a combination of low dose heparin and graded compression stockings, two had thromboembolism, and of 85 receiving a combination of dextran and graded compression stockings, 13 had this complication. This difference is significant in favor of the second treatment (p = 0.013). It is concluded that the combination of low dose heparin and graded compression stockings is an effective way to prevent thromboembolism after acute abdominal operations. Deep vein thrombosis (DVT) and subsequent pulmonary embolism (PE) is a major source of mortality and morbidity in stroke patients. This study was designed to determine the effectiveness of different prophylactic treatments in the prevention of DVT after a stroke in patients undergoing rehabilitation. An additional objective was the identification of risk factors for DVT in stroke in patients during rehabilitation. Three hundred and sixty patients, over a 3-year period, were randomly assigned to one of four groups: adjusted dose heparin, intermittent pneumatic compression (IPC), functional electrical stimulation (FES), or control. There was no significant difference in the development of DVT by treatment group. Patients with DVT on admission (prevalent, n = 61) were compared with the study patients (n = 360). Time interval (from stroke to admission) and lactic dehydrogenase (LDH) concentration were significant risk factors, as well as predictors, for development of DVT (p < .000). These results suggest that the longer a patient remains without DVT prophylaxis after a stroke, the greater the risk of developing DVT and this supports early prophylaxis before rehabilitation. The effect of low-dose heparin prophylaxis on venous thrombosis and bleeding after major elective surgery was studied in a prospective controlled study of 820 patients. The total incidence of venous thrombosis detected with leg-scanning using fibrinogen labeled with radioactive iodine (125I) was reduced from 16.0% in the control group to 4.2% in treated patients. More important, the incidence of popliteal or femoral vein thrombosis was reduced from 2.9% to 1.0%. Prophylaxis resulted in a slight increase in bleeding-minor wound hematoma, mean volume of blood transfused, and a post-operative hematocrit fall in treated patients. However, increased bleeding was clinically minor, and prophylaxis was well tolerated. The incidence of deep venous thrombosis (DVT) and the efficacy of prophylactic measures were prospectively evaluated in all patients admitted to a level I trauma center during 1991. Patients with Injury Severity Scores (ISS) > 9 who survived a minimum of 48 hours (n = 395) were monitored using venous Doppler and ultrasound studies during hospitalization (total, 1308 studies). Two hundred eighty-one patients (71%) were randomly assigned to low-dose heparin or sequential compression devices. There were 18 cases of lower extremity DVT (4.6%) and four cases (1.0%) of pulmonary emboli (PE), three of which were fatal. Eight patients (2.9%) on prophylaxis and 10 (8.8%) without prophylaxis developed DVT (p < 0.02 by Chi-square). There were two PEs in each group. Fourteen of these 18 patients sustained blunt trauma and included seven spinal fractures or subluxations (four paraplegic) and four severe head injuries. This represented 14.0% of 50 patients admitted with spinal injuries and 4.3% of 92 patients with severe head injuries. Compared with those with no neurologic injury (7 of 253 or 2.7%), the risk of DVT is significantly higher in the spinal injury patients (p < 0.001, Chi-square) and twice as high as in the head injury group, although not statistically significant (p = 0.4, Chi-square). Three of the four patients with penetrating trauma and DVT had venous injuries. We conclude that DVT prophylaxis can significantly reduce the incidence of DVT in trauma patients with ISS > 9. Patients with severe neurologic injuries (particularly spinal cord) are at high risk for DVT and PE and may be considered for a prophylactic Greenfield filter.
Compared with compression alone, combined prophylactic modalities decrease significantly the incidence of venous thromboembolism. Compared with pharmacological prophylaxis alone, combined modalities reduce significantly the incidence of DVT but the effect on PE is unknown. The results of the current review support, especially in high-risk patients, the use of combined modalities. More studies on their role in PE prevention, compared with pharmacological prophylaxis alone, are urgently needed.