Mechanical prophylaxis against deep-vein thrombosis after pelvic and acetabular fractures.

BACKGROUND: Deep-vein thrombosis is a common complication following pelvic and acetabular fractures. The hypothesis of this study was that pulsatile mechanical compression is superior to standard sequential mechanical compression for decreasing the prevalence of deep-vein thrombosis in patients with pelvic or acetabular fracture. METHODS: A prospective, randomized, blinded study of two methods of mechanical prophylaxis against deep-vein thrombosis was conducted. One hundred and seven patients were randomized into either Group A (fifty-four patients), in which a thigh-calf low-pressure sequential-compression device was used, or Group B (fifty-three patients), in which a calf-foot high-pressure pulsatile-compression pump was used. All patients underwent duplex ultrasonography and magnetic resonance venography. The two groups were comparable with regard to demographics, fracture type, fracture treatment, time from the injury to the prophylaxis, and patient compliance. RESULTS: Deep-vein thrombosis developed in ten patients (19%) in Group A, with seven (13%) having a large or occlusive clot and one (2%) having a documented pulmonary embolism. Deep-vein thrombosis developed in five patients (9%) in Group B, with two (4%) having a large or occlusive clot and none having a documented pulmonary embolism. Nine of the nineteen detected thromboses were in the deep pelvic veins. The difference in the prevalence of large or occlusive clots between the two groups demonstrated a trend but, with the numbers available, was not significant (p = 0.16). Increased patient age and the time elapsed from the injury to the surgery were found to be associated with higher rates of thrombosis. CONCLUSIONS: Pulsatile compression was associated with fewer deep-vein thromboses than was standard compression, with the difference representing a trend but not reaching significance with the number of patients studied.     

Intraoperative single-dose heparin prophylaxis against deep-vein thrombosis

This randomized prospective study examines the efficacy of intravenously administered heparin as prophylaxis against deep-vein thrombosis, detected isotopically with iodine 125, in 37 patients scheduled to undergo major abdominal procedures. Twenty patients were given 5000 units of sodium heparin on opening the abdominal cavity, while 17 patients who did not receive heparin acted as controls. The effect of heparin was reversed at the end of the operative procedure by protamine. Three control patients had deep-vein thrombosis postoperatively but only one heparin-treated patient did. Complications in the treated group included excessive blood loss intraoperatively in one patient and an incisional hernia postoperatively in another. Although the results are not statistically significant, this study suggests that a single dose of heparin given intravenously during operation is a safe and effective means of prophylaxis against deep-vein thrombosis in patients who undergo general surgical procedures. Studies are now being carried out to determine the optimal dose of heparin, time of administration and duration of anticoagulation.     

Pneumatic sequential-compression boots compared with aspirin prophylaxis of deep-vein thrombosis after total knee arthroplasty

This prospective, randomized study was undertaken to compare the effectiveness of pneumatic sequential-compression boots with that of aspirin in preventing deep-vein thrombosis after total knee arthroplasty. Patients were randomly assigned to one of two prophylactic regimens: compression boots or aspirin. One hundred and nineteen patients completed the study. Seventy-two patients had unilateral arthroplasty and forty-seven, one-stage bilateral arthroplasty. In the unilateral group, the incidence of deep-vein thrombosis was 22 per cent for the patients who used compression boots compared with 47 per cent for those who received aspirin (p less than 0.03). In the bilateral group, the incidence of deep-vein thrombosis was 48 per cent for the patients who used compression boots compared with 68 per cent for those who received aspirin (p less than 0.20). The results confirm the effectiveness of compression boots in the treatment of patients who have had unilateral total knee arthroplasty. Despite the use of compression boots, however, patients who had bilateral arthroplasty were at greater risk for the development of deep-vein thrombosis.     

低分子肝素预防人工髋、膝关节置换术后下肢深静脉血栓形成的研究

目的 对比观察采用低分子有直素预防人工髋、膝置换术（ＴＨＲ、ＴＫＲ）后下肢深静脉血栓形成（ＤＶＴ）的临床效果。方法 将１９９７掉１１月－１９９９年３月行人工髋膝置换术的患者随机分为未用药组和用药组,其中未用药组共４７例患者,６２例关节置换,未预防性使用低分子肝素抗凝;用药组共３１例患者,３６例关节置换（１９膝,１７髋）,围手术期给予低分子肝素预防治疗。两组患者均于术后行下肢静脉造影检查。结果 用药     

Outcome of calf deep-vein thrombosis after total knee arthroplasty

We investigated the outcome of deep-vein thrombosis (DVT) in the calf after total knee arthroplasty (TKA) in 48 patients (45 women and three men) by clinical assessment and venographic study between three and four years after surgery. The mean age of the patients was 67.2 +/- 7.7 years (52 to 85) and the mean follow-up was 42.6 +/- 2.7 months (38 to 48). The diagnosis was osteoarthritis in 47 patients and rheumatoid arthritis in one patient. There were 44 calf thrombi, four popliteal thrombi but no thrombi in the femoral or iliac regions. Of the 48 patients, 24 were clinically symptomatic and 24 were asymptomatic. Clinical examination was carried out on 41 patients, of whom 37 underwent ascending venography. Seven were evaluated by telephone interview. No patient had the symptoms or signs of recurrent DVT, venous insufficiency in the affected leg, or a history of pulmonary embolism. No patient had been treated for complications of their DVT. Thirty-six of the 37 venographic studies were negative for either old or new DVT in the affected leg. One patient had residual thrombi in the muscular branches of the veins. Our study shows that deep-vein thromboses in the calf after TKA disappear spontaneously with time. No patient developed a recurrent DVT, proximal propagation or embolisation. Treatment of DVT in the calf after TKA should be based on the severity of the symptoms during the immediate postoperative period.     

Mechanical prophylaxis of deep-vein thrombosis after total hip replacement a randomised clinical trial

Routine prophylaxis for venous thromboembolic disease after total hip replacement (THR) is recommended. Pneumatic compression with foot pumps seems to provide an alternative to chemical agents. However, the overall number of patients investigated in randomised clinical trials has been too small to draw evidence-based conclusions. This randomised clinical trial was carried out to compare the effectiveness and safety of mechanical versus chemical prophylaxis of DVT in patients after THR. Inclusion criteria were osteoarthritis of the hip and age less than 80 years. Exclusion criteria included a history of thromboembolic disease, heart disease, and bleeding diatheses. There were 216 consecutive patients considered for inclusion in the trial who were randomised either for management with the A-V Impulse System foot pump. We excluded 16 patients who did not tolerate continuous use of the foot pump or with low-molecular-weight heparin (LMWH). Patients were monitored for DVT using serial duplex sonography at 3, 10 and 45 days after surgery. DVT was detected in three of 100 patients in the foot-pump group and with six of 100 patients in the LMWH group (p < 0.05). The mean post-operative drainage was 259 ml in the foot-pump group and 328 ml in the LMWH group (p < 0.05). Patients in the foot-pump group had less swelling of the thigh (10 mm compared with 15 mm; p < 0.05). One patient developed heparin-induced thrombocytopenia. This study confirms the effectiveness and safety of mechanical prophylaxis of DVT in THR. Some patients cannot tolerate the foot pump.     

Prophylaxis against deep-vein thrombosis following trauma: a prospective, randomized comparison of mechanical and pharmacologic prophylaxis

BACKGROUND: Deep-vein thrombosis following skeletal trauma is an important yet poorly studied issue. The purpose of the present study was to evaluate the efficacy of two different strategies for prophylaxis against deep-vein thrombosis and pulmonary embolus following blunt skeletal trauma. METHODS: Two hundred and twenty-four inpatients were enrolled in a prospective, randomized study investigating venous thromboembolic disease following trauma. Two hundred patients completed the study, which compared two different regimens of prophylaxis. The patients in Group A received enoxaparin (30 mg, administered subcutaneously twice a day) starting twenty-four to forty-eight hours after blunt trauma. The patients in Group B were managed with pulsatile foot pumps at the time of admission combined with enoxaparin on a delayed basis. All patients were screened with magnetic resonance venography and ultrasonography before discharge. RESULTS: There were ninety-seven patients in Group A and 103 patients in Group B. Twenty-two patients (including thirteen in Group A and nine in Group B) had development of deep-vein thrombosis, with two (both in Group A) also having development of pulmonary embolism. The prevalence of deep-vein thrombosis was 11% for the whole series, 13.4% for Group A, and 8.7% for Group B; the difference between Groups A and B was not significant. There were eleven large or occlusive clots (prevalence, 11.3%) in Group A, compared with only three (prevalence, 2.9%) in Group B (p = 0.025). The prevalence of pulmonary embolism was 2.1% in Group A and 0% in Group B. Wound complications occurred in twenty-one patients in Group A, compared with twenty patients in Group B. Patients who had development of deep-vein thrombosis during the inpatient portion of the study required a mean of 7.4 units of blood during hospitalization, compared with 3.9 units of blood for those who did not (p < 0.05). CONCLUSIONS: Our results indicate that early mechanical prophylaxis with foot pumps and the addition of enoxaparin on a delayed basis is a very successful strategy for prophylaxis against venous thromboembolic disease following serious musculoskeletal injury. The prevalence of large or occlusive deep-vein thromboses among patients who had been managed with this protocol was significantly less than that among patients who had been managed with enoxaparin alone.     

Low-dose warfarin coupled with lower leg compression is effective prophylaxis against thromboembolic disease after hip arthroplasty

Consecutive patients having elective total hip arthroplasty were prescribed 1 mg of warfarin for 7 days preceding surgery, variable doses while in hospital (target international normalized ratio, 1.5-2.0), and discharged to rehabilitation center or home taking 1 mg daily until 4-week to 6-week follow-up visit. Lower leg pneumatic compression was used postoperatively and elastic compression stockings after discharge. Hospital and clinic charts plus auxiliary sources were reviewed for evidence of thromboembolic diseases (TED). Of 1003 consecutive patients studied, 3 (0.3%, 95% CI 0.0-0.6%) had symptomatic TED, including 2 with deep venous thrombosis and 1 with nonfatal pulmonary embolus. Follow-up rate was 99.1%. Complications from warfarin were minimal. Very-low-dose warfarin coupled with lower leg compression is effective prophylaxis against TED after elective hip arthroplasty when prescribed as described.     

Effects of epidural anesthesia on the incidence of deep-vein thrombosis after total knee arthroplasty

Epidural anesthesia has been reported to reduce the prevalence of deep-vein thrombosis after total hip arthroplasty compared with the prevalence after general anesthesia. However, the effect of epidural anesthesia on the rate of thrombosis after total knee arthroplasty has not been reported previously, to our knowledge. A review was conducted of 705 total knee arthroplasties (541 patients) that had been performed by a single surgeon between September 1984 and December 1988. During this period, the operative technique, the protocol for rehabilitation, and the regimen for prophylaxis against thromboembolism did not change meaningfully. The patients received either epidural or general anesthesia. Preoperative and postoperative perfusion scans of the lungs and a venogram of the lower limb or limbs that had been operated on were done for all patients. For the 227 patients who had received epidural anesthesia, the over-all rate of deep-vein thrombosis was 48 per cent, which was significantly lower than the 64 per cent incidence in the 264 patients who had received general anesthesia (p less than 0.0001). The greatest reduction was in the occurrence of proximal thrombosis, which was identified in 9 per cent of the patients who had had general anesthesia but in only 4 per cent of those who had had epidural anesthesia (p less than 0.05). The use of epidural anesthesia reduced the incidence of proximal thrombosis after both unilateral and one-stage bilateral arthroplasty.     

Heparin and dihydroergotamine prophylaxis against thrombo-embolism after hip arthroplasty

A prospective study involving 500 consecutive patients undergoing hip replacement was performed to find out whether a combination of heparin and dihydroergotamine was effective in preventing postoperative fatal and non-fatal emboli. Deep-vein thrombosis was demonstrated in 131 cases (26.2%), in 99 of whom thrombi were confined to the ipsilateral (operated) limb and in 13 to the contralateral limb; 19 patients developed bilateral thrombi. Nine patients (1.8%) died during the first four weeks after operation, before they were discharged from hospital; in one, major emboli were demonstrated in the right pulmonary artery. Three of the 500 patients developed non-fatal pulmonary emboli. Excessive bleeding occurred in 21 (4.2%) and in 19 of these prophylaxis was discontinued. Wound haematomas developed in 25 patients (5.0%); only six required evacuation but in none of these six did deep infection occur while in hospital; in three patients, however, the wound haematoma prolonged the stay in hospital. Thus the combination of heparin and dihydroergotamine proved an effective prophylaxis against pulmonary embolism in patients undergoing total hip replacement. The risk of bleeding complications is wholly acceptable when balanced against the advantages of the therapy.     

Low-dose warfarin prophylaxis to prevent symptomatic pulmonary embolism after total knee arthroplasty

Pulmonary embolism poses a risk to patients undergoing total knee arthroplasty. The selection of an appropriate prophylaxis agent and its implementation have been influenced by decreased duration of hospital stay and the pressures of cost containment. The purpose of this study was to determine the inpatient and outpatient pulmonary embolism rates, the number of days required to attain the target level of anticoagulation, and complications associated with the use of a low-dose warfarin prophylaxis protocol after primary and revision total knee arthroplasty. Between 1984 and 1993, there were 815 primary and revision total knee arthroplasties that received low-dose warfarin prophylaxis at our institution. The average time to attainment of the target level of anticoagulation was 3 days. The average duration of warfarin prophylaxis was 12 days. Overall, there were a total of three symptomatic pulmonary embolisms (0.3%; 95% confidence interval, 0.08%–1.1%). There were eight (1%) symptomatic deep vein thromboses (all distal). There were two deaths (0.3%), but neither one was secondary to a pulmonary embolism. Seventeen knees (2.5%) developed a hematoma after surgery, and two of these patients required drainage of the knee. Low-dose warfarin prophylaxis is safe and effective in preventing symptomatic pulmonary embolism after total knee arthroplasty.     

The effect of preoperative donation of autologous blood on deep-vein thrombosis after total hip arthroplasty

We have assessed the effect of the donation of autologous blood and the preoperative level of haemoglobin on the prevalence of postoperative thromboembolism in 2043 patients who had a total hip arthroplasty. The level of haemoglobin was determined seven to ten days before surgery and all patients had venography of the operated leg on the fifth postoperative day. The number of patients who had donated autologous blood (1037) was similar to that who had not (1006). A significant decrease in the incidence of deep-vein thrombosis (DVT) was noted in those who had donated blood preoperatively (9.0%) compared with those who had not (13.5%) (p = 0.003). For all patients, the lower the preoperative level of haemoglobin the less likely it was that a postoperative DVT would develop. Of those who had donated blood, 0.3% developed a postoperative pulmonary embolism compared with 0.7% in those who had not, but this difference was not statistically significant. No significant difference was found in the requirements for transfusion between the two groups.     

Postoperative hypercoagulability and deep-vein thrombosis after laparoscopic cholecystectomy

Patients who undergo laparoscopic cholecystectomy (LC) are operated on under general anesthesia, in a reverse Trendelenburg position, with 12–15-mmHg pneumoperitoneum. All of these factors can induce venous stasis of the legs, which may lead to postoperative deep-vein thrombosis (DVT). The objectives of this study were to assess the degree of hypercoagulability and to determine the rate of postoperative DVT in a group of 100 patients in whom LC was completed. Whole-blood thrombelastography (TEG) and plasma-activated partial thromboplastin time (PTT) determination were carried out preoperatively and on the 1st postoperative day. All patients received pre-, intra-, and postoperative graduated compression stockings and sequential pneumatic compression devices until fully ambulatory. Twenty-six percent of the patients with a risk score >4, or a postoperative TEG index >+5.0, received subcutaneous heparin (5,000 units b.i.d.), beginning in the postoperative period and continuing for 4 weeks as an outpatient. A complete venous duplex scan of both legs was performed on the 7th postoperative day, at the time of their office visit.Our results revealed significant postoperative hypercoagulability for the TEG index (P<0.005) and for PTT (P<0.05). One patient had an asymptomatic DVT (1%), and no side effects from the mechanical or pharmacological prophylaxis occurred in this series.These data suggest that the low incidence of thrombosis in the face of theoretical and laboratory evidence of postoperative hypercoagulability may reflect an effective prophylactic regime. Alternatively, the incidence of these thrombotic problems may be very low, or the sensitivity and timing of duplex scanning may be inadequate to identify asymptomatic venous thrombosis. Until further studies are done to resolve these issues, we feel that mechanical prophylaxis combined with selective low-dose heparin therapy is safe and effective in patients having laparoscopic cholecystectomy.Presented at the annual meeting of the Society of American Gastrointestinal Endoscopic Surgeons (SAGES), Nashville, TN, 18–19 April 1994     

Incidence and natural history of deep-vein thrombosis after total knee arthroplasty. A prospective,randomised study

We have evaluated prospectively the incidence and location of deep-vein thrombosis (DVT), the risk factors for pulmonary embolism, and the natural history of thrombosis after total knee replacement (TKR) in patients who did not receive prophylactic or therapeutic treatment for DVT. We studied 227 patients who underwent primary TKR; 116 had one-stage bilateral and 111 unilateral procedures. Coagulation assays, the full blood count and blood typing tests for the serum chemical profile were undertaken in all patients on three separate occasions. Bilateral simultaneous or unilateral venograms were carried out at six or seven days after operation. Perfusion lung scanning was undertaken before and at seven or eight days after operation. Bilateral simultaneous or unilateral venograms were repeated six months after operation in all patients who had thrombi. In the 116 patients with a bilateral replacement, 97 of 232 venograms (41.8%) were positive for fresh thrombi while there were 46 positive venograms (41.4%) in the 111 patients with a unilateral replacement (p = 1.000). Of the 116 venograms in knees with a cemented replacement, 45 (38.8%) were positive for thrombi while 52 of the 116 venograms (44.8%) were positive in those with a cementless replacement (p = 0.675). Further venograms at six months after operation in all 143 limbs which had thrombi showed that all had completely resolved regardless of the size or location. No pulmonary embolism occurred as shown by negative perfusion lung scans and the absence of symptoms. Although the current prevailing opinion is that patients with thrombosis in the proximal veins should receive anticoagulant treatment, our study has shown that all thrombi regardless of their size or location resolved without causing pulmonary embolism.     

Incidence and natural history of deep-vein thrombosis after total hip arthroplasty. A prospective and randomised clinical study

There are many reports concerning the aetiology and prophylaxis of deep-vein thrombosis (DVT) but little is known about its natural history. The purpose of our study was to identify the incidence and site of DVT, the risk factors for pulmonary embolism and the natural history of DVT after total hip replacement (THR) in patients who do not receive any form of prophylactic or therapeutic treatment for DVT. Two hundred patients who had a primary THR were included: 100 had one-staged bilateral THR and 100 had unilateral THR and 150 implants were cemented and 150 cementless. Coagulation assays, a full blood count, blood typing and serum chemical profile tests were performed for all patients on three separate occasions. Bilateral simultaneous or unilateral venograms were performed on the sixth or seventh postoperative day and perfusion lung scans preoperatively and on the seventh or eighth postoperative day. Further venograms were performed in all patients who had thrombi six months later. In the patients with bilateral THR, 52 (26%) venograms were positive for thrombi, while in the patients with unilateral THR 20 (20%) were positive (p = 0.89). In the patients with a cemented THR, 31 venograms (20.7%) were positive for thrombi, while in those with a cementless THR 41 (27.3%) were positive (p = 0.654). Further venograms in all 72 patients who had thrombi at six months after operation showed that they resolved completely and spontaneously regardless of their site and size. No patients had symptoms of pulmonary emboli and none were seen on the perfusion lung scans. Two patients died from unrelated causes. Although the prevailing opinion is that patients with proximal venous thrombosis should be treated with anticoagulants, our study has shown that all thrombi regardless of their site and size resolve spontaneously without associated pulmonary embolism.