Post-operative thromboembolism in neurosurgery

Summary This study compares the safety and effectiveness of two methods for the prophylaxis of post-operative thromboembolism in neurosurgical patients: A: low-dose heparin (5,000 IU×2 s.c.) started preoperatively and continued daily for one week post-operatively, and B: per-operative electrical calf muscle stimulation with groups of impulses plus post-operative dextran infusions every other day for one week.Neurosurgical patients aged 40 years or more with normal laboratory coagulation values and operated under general anaesthesia were included. The 125:I-fibrinogen uptake test (FUT) was used for screening and phlebography for verification of deep venous thrombosis (DVT). 122 patients entered the study and 104 completed the prophylactic protocol, 58 in group A and 46 in group B. The two groups were comparable according to pre-operative data and distribution of diagnoses.89 patients completed screening for post-operative DVT. We found an overall incidence of 5/49 (10 percent) DVT in group A and 5/40 (13 percent) in group B, compared to a frequency of 32–50 percent for controls without prophylaxis reported in the literature^{6, 16, 18}. In spite of prophylaxis our patients with intracranial neoplasms and intracranial vascular disease showed a relatively higher incidence of DVT, 4/23 (17 percent) and 4/14 (29 percent) respectively, compared to patients with spinal diagnoses 2/25 (8 percent). In combination with cranial diagnoses paretic lower limbs meant an apparent risk factor, 4/7 (57 percent). However, paretic limbs appearing in cases with spinal disorders did not predetermine an unsuccessful prophylaxis, 2/14 (14 percent).Blood loss, transfusion requirements and post-operative complications did not differ significantly between the two prophylactic groups.It is concluded that both methods reduce the incidence of post-operative DVT in neurosurgical practice and that they can be used with safety. However, the basic mechanisms behind thromboembolism following parenchymatous brain lesions ought to be studied further to enable a better understanding of the thromboembolic complications and further improvement of the prophylaxis.     

Venous thromboembolism in pregnancy

A DUAL CHALLENGE: Pregnancy is a physiological state favoring the development of venous thromboembolism and sometimes discloses a coagulation disorder. Due to the presence of the fetus, suspected venous thromboembolism in a pregnant woman raises a dual challenge for the clinician: confirmation of the clinically suspected diagnosis using imaging techniques exposing the fetus to as little radiation as possible, and adapted anticoagulant therapy taking into account the teratogenic risk. MILD TO MODERATE DISEASE: Excepting exceptionally severe cases, the only validated long-term treatment is continuous infusion heparin. However, because of the difficulties inherent in the use and control of this type of administration, most clinicians prefer low-molecular-weight heparins (LMWH) although these pharmaceutical products have not acquired official approval for this indication. PREVENTION: The optimal therapeutic approach for prevention of venous thromboembolism in a pregnant woman with an acquired or hereditary coagulation disorder or a history of venous thromboembolism remains to be defined. New clinical trials are needed to validate the use of LMWH in this indication and determine the therapeutic approach in certain risk situations and at delivery.     

Venous thromboembolism prophylaxis

Venous thromboembolism is a common and frequent complication of hospitalized patients. Some venous thromboembolisms may be subclinical, while others present as symptomatic deep vein thrombosis and/or pulmonary embolism. Venous thromboembolism and pulmonary embolism contribute significantly to inhospital morbidity and mortality. The risk of venous thromboembolism is aggravated by dispositional and/or expositional risk factors. In patients at intermediate or high risk of venous thromboembolism, additional pharmacological thromboembolism prophylaxis becomes mandatory.     

Venous thromboembolism in trauma patients

Serial venous duplex scans (VDS) were done in 507 trauma patients with at least one risk factor (RF) for venous thromboembolism (VTE) during a 2-year study period. Deep vein thrombosis (DVT) was detected in 31 (6.1%) patients. This incidence was 3.1 per cent in low (1-2 RFs), 3.4 per cent in moderate (3-5 RFs), and 7.7 per cent in high (> or =6 RFs) VTE scores (P = 0.172). Incidence was statistically different (3% vs. 7.2%, P = 0.048) on reanalyzing patients in two risk categories, low-risk (1-4 RFs) and high-risk (> or =5 RFs). Only 4 of 16 RFs had statistically higher incidence of DVT in patients with or without RFs: previous VTE (27.3% vs. 5.6%, odds ratio (OR) 6.628, P = 0.024), spinal cord injury (22.6% vs. 5%, OR 5.493, P = 0.001), pelvic fractures (11.4% vs. 5.1%, OR 2.373, P = 0.042), and head injury with a greater than two Abbreviated Injury Score (10.5% vs. 4.2%, OR 2.639, P = 0.014). On reanalyzing patients with > or =5 RFs vs. <5RFs, obesity (14.3 vs. 6.1%, P = 0.007), malignancy (5.6% vs. 0.6%, P = 0.006), coagulopathy (10.8% vs. 1.8%, P = 0.000), and previous VTE (3.2% vs. 0%, P = 0.019) were significant on univariate analysis. Patients with DVT had 3.70 +/- 1.75 RFs and a 9.61 +/- 4.93 VTE score, whereas, patients without DVT had 2.66 +/- 1.50 RFs and a 6.83 +/- 3.91 VTE score (P = 0.000). DVTs had a direct positive relationship with higher VTE scores, length of stay, and number of VDS (>1 r, P < or = 0.001). Increasing age was a weak risk factor (0.03 r, P = 0.5). First two VDS diagnosed 77 per cent of DVTs. Patients with injury severity score of > or =15 and 25 had higher DVTs compared with the ones with lower injury severity score levels (P < or = 0.05). Pulmonary embolism was silent in 63 per cent and DVTs were asymptomatic in 68 per cent.     

Venous thromboembolism in spine surgery

Venous thromboembolism is a life-threatening adverse event in spine patients and presents difficult decisions for the surgeon and patient. Prophylactic protocols have been established to prevent the occurrence of venous thromboembolism and its sequelae, including venous occlusion, edema, postthrombotic syndrome, and death. Despite the known benefits of prophylaxis, some surgeons choose not to use it because of concerns over increased bleeding complications and possible iatrogenic neurologic injury. Although mechanical prophylaxis remains an important element in venous thromboembolism prevention, low-molecular-weight heparin is better than other pharmacologic therapies in decreasing the incidence of major events.     

Venous thromboembolism and cancer

Background: Venous thromboembolism (VTE) remains one of the most important causes of mortality and morbidity in the hospitalized patient. This is particularly evident in patients with cancer who are exposed to a four‐ to sixfold increased risk of VTE compared with those patients without cancer. Methods: A review of the current literature was undertaken on prophylaxis and management of VTE in patients with cancer. Results: Primary VTE prophylaxis is recognized to be the single most effective strategy that improves patient safety. Many clinical trials have demonstrated the benefit of primary prophylaxis for patients with cancer and evidence‐based, best practice guidelines for specific subgroups of patients with cancer are well accepted by most clinicians. Despite this, many patients at high risk for VTE either receive no VTE prophylaxis or are exposed to VTE complications due to sub‐optimal prophylaxis. Implementation of best practice guidelines still falls far short of clinical acceptable levels for VTE prophylaxis and management. Conclusion: VTE prevention in patients with cancer results in reduced morbidity and mortality, outcomes that are unquestionably attainable. This review of the current evidence supporting VTE prophylaxis in patients with cancer will hopefully act as a stimulus to provide patients with cancer access to the best, evidence‐based, thromboprophylactic management available.     

Venous thromboembolism in pediatric nephrotic syndrome

Childhood nephrotic syndrome (NS) is one of the most common pediatric kidney diseases, with an incidence of 2–7 per 100,000. Venous thromboembolism (VTE) is associated with significant morbidity and mortality, and occurs in ～3 % of children with NS, though incidence approaches 25 % in high-risk groups. VTE etiology is multifactorial, with disease-associated coagulopathy thought to be a significant contributor. Other risks include age, disease severity, and treatment-related hazards, such as the presence of central venous catheters. Non-pharmacologic preventive measures such as ambulation and compression stockings are recommended for patients with identified VTE risks. Central venous catheters should be avoided whenever possible. Symptoms of VTE include venous catheter dysfunction, unilateral extremity symptoms, respiratory compromise, flank pain, and gross hematuria. When VTE is suspected, confirmatory imaging studies should be obtained, followed by appropriate laboratory evaluation and treatment. Therapeutic goals include limiting thrombus growth, extension, and embolization by early institution of anticoagulant therapy. Anticoagulation is recommended for a minimum of 3 months, but should be continued until NS remission is achieved. Further studies are necessary to identify VTE-risk biomarkers and optimal therapeutic regimens. Observational cohort studies are needed to identify VTE-risk groups who may benefit from thromboprophylaxis and to define disease-specific treatment algorithms.     

Venous thromboembolism following total knee replacement

Venous thromboembolic disease (VTE) remains the most common and potentially fatal complication following total knee replacement (TKR). Its incidence has been reported in excess of 50% if no prophylaxis is used. Even with current prophylaxis regimens, VTE incidence remains high in the range of 25% to 30%. Three prophylaxis regimens are recommended according to the guidelines put forth by the American College of Chest Physicians: 1) low-molecular-weight heparin, 2) indirect factor Xa inhibitor, and 3) adjusted-dose warfarin. Phase II and III clinical trials are currently underway to evaluate the efficacy and safety of newer antithrombotic agents as prophylaxis against VTE following TKR.