VARIABILITY OF STANDARDS OF DIAGNOSTICS, PREVENTION AND TREATMENT OF VENOUS THROMBOSIS IN PATIENTS IN TRAUMATOLOGY AND ORTHOPEDICS
Regional Clinical Center of Miners’ Health Protection,
Leninsk-Kuznetsky, Russia
Venous thromboembolic complications (VTEC) including deep venous thrombosis (DVT) and pulmonary embolism (PE) are the common causes of morbidity and mortality among patients with traumatic injuries. PE is the third main cause of death in patients with injuries who survive within 24 hours after injuries [1]. PE is one of the main causes of death within the first months after surgical interventions including joint implantation. Considering the significance of this clinical problem one could assume necessity for standardization of prevention and treatment of VTEC in most trauma centers. But the experience shows that this is far from being the case. Even among foreign trauma centers one may find the groundless variability in such issues as usage of cava-filters or thrombosed vein ligation, duplex ultrasonic scanning in patients with absent symptoms of DVT, realization of additional tests for thrombophilia or hypercoagulation, and various types of anticoagulant therapy for probable bleeding [1]. Moreover, the number of lethal outcomes after PE increases annually. This is the general worldwide tendency, which is associated with worsening state and increasing age in operated patients [2].
The main technique of DVT diagnostics is color duplex scanning (CDS). This technique is the gold standard of diagnostics of thrombosis in veins of the extremities [3, 4]. For the recent years use of CDS for the veins of the lower extremities is obligatory for examining patients before planned surgical interventions. Adherence to this rule allows clearing the risk of development of VTEC.
However use of CDS is variable among orthopedists and traumatologists. The variability is associated with frequency of use of CDS for patients with injuries to the extremities and the pelvis, after extensive orthopedic operations, different terms of conduction of CDS, and the volume of an examination.
The variability of the rates of thrombotic complications after injuries and orthopedic operations is very high: from 20 till 80 % according to the data of the studies. Besides other causes, according to our opinion, the rate of thrombotic complications is influenced by reasonableness of use of CDS in the clinic.
DVT is characterized with some clinical features in patients with orthopedic pathology or with injuries to the lower extremities. It is known that asymptomic DVT develops within the first week after plastic orthopedic procedures, with location in leg veins in 95 % of cases and in the proximal veins in only 5 % [5, 6]. Asymptomic course of DVT is associated with mainly isolated lesion of one of the couple of leg veins, with persistence of normal venous outflow from the leg. Muscular veins of the leg are the primary location of clot formation in most patients with DVT. It is associated with the sinusoidal structure of the veins. In 20-25 % of cases thrombosis extends to the popliteal and femoral veins; in 50 % it results in PE [7, 8, 9]. However full examination of leg veins is associated with some difficulties relating to severity of patient’s condition, realization of curative measures, deepness of veins in patients with excessive body mass, intense edema of an extremity [10].
The muscular veins of the leg are not included in the protocols of ultrasonic examination in some clinics. The rate of false negative examinations reaches 40 % [11]. Terms and frequency of use of CDS are also quite variable. In case of obligatory CDS for all operated patients it is conducted in 1-2 days after surgical treatment. The mean interval between examinations is 3-6 days from the moment of the injury. Thrombotic states with possibility of embolia were identified in various terms after injuries (7-21 days) and after osteosynthesis (5-15 days) [12]. Because of different possible terms of clot formation we considered that it was obligatory to repeat CDS before recurrent intervention, transition to vertical positioning the patient, extension of motion mode, before initiation of remedial gymnastics, massage etc.
Estimation of embolic potential of clots is not a simple task. One of the main criterions is the length of the mobile part of a clot, degree of mobility and presence of concentric blood flow [13, 14, 15]. However various researchers note insufficiency of ultrasonic signs according to their ability to estimate the degree of threat and a possibility of an error during estimation of embolic potential. Moreover, it is shown that screw-shaped and segmental types of fixation of a clot are associated with persistent embolic potential even after fixation [16]. As result, various clinics use various criterions of embolic potential.
The next step of use of CDS for patients after orthopedic operations is dynamic examination in late postsurgical period and after discharge from the hospital. There are no clear criteria for prescription of CDS in definite terms. Prescription of CDS is made at outpatient admission according to the indications: water retention in an extremity, pain syndrome. At the same time, the acknowledged fact is symptomless course of DVT in such patients. We conducted the analysis in 2011. It found presence of thrombotic complications in patients after endoprosthetics of big joints. These complications developed within the period from a week to a month after discharge from the hospital. The rate of late complications was 1.4 % [17].
Therefore, there is a need for development of clear criteria for examining patients not only after injuries and during hospital treatment, but also during outpatient observation after hospital discharge.
Pharmacologic prevention is widely used in the world. However the variability exists in terms of used drugs, frequency, dosage and duration of usage. There is an opinion that it is associated with different risk of VTEC in various patients [18]. However, according to our opinion, the risk of DVT is related to some specific factors of clotting. These are basic venous pathology of the lower extremities, endothelial dysfunction and the features of surgical intervention [19] in case of planned implant of joints, as well injury severity and severity of patient’s condition, volume of surgical treatment and blood loss in case of polytrauma [20]. Pathogenetic prevention should be differentiated in dependence on identified risk factors and is oriented to quick correction of risk factors. It is necessary to develop new methods of treatment of traumatic disease, quick and less invasive restoration of injured structures, and to improve analgesic techniques. There is no uniform approach to perisurgical analgesia, but the main directions for its development have been defined: implementation of efficient and safe regional techniques, minimal use of opioid analgetics, smooth transition of intrasurgical analgesia to postsurgical period, a possibility for maximally earliest activation of the patient, an ability of an analgesic technique to decrease perisurgical blood loss and frequency of thromboembolic and other complications [21]. Moreover, patients with polytrauma should be examined and treated in level 1 hospitals. For this purpose they are transported with specific reanimobiles and resuscitation teams.
Symptomatic anticoagulant therapy should not increase risk of bleeding, and it is initiated only after arresting of bleedings in bones, cavities and in the cranium. According to our data, there are no statistically significant differences in use of low molecular weight heparin, continuous infusion of non-fractionated heparin, and tableted pharmaceuticals of direct and indirect inhibitors of thrombin. Physicians choose a drug on the basis of its comfortable administration.
A choice of measures for treating a patient with floating thrombosis is made on individual basis with consideration of location of the proximal part of a clot and its length, as well as patient’s age and his/her somatic status. Some authors consider the fact of fixation of floating clots, and they adhere to conservative treatment, if the length of the apex of a clot does not exceed 2 cm [22]. However it determines necessary immobilization and increases risk of complications in such category of patients. A long apex of a clot, its unsmooth contours or an event of microembolia are the indications for surgical treatment, which is an absolute indication in the case of impossible anticoagulant therapy [23].
There is no a uniform concept of surgical prevention of PE in the international practice. American physicians use a radical approach with placement of cava-filters with consideration of embolic capacity of a clot. More than 10,000 operations are conducted each year [24]. In the countries of Western Europe it is recommended to implant a cava-filter only in cases of impossible anticoagulant therapy for PE. Prevention of pulmonary embolia is realized with anticoagulant drugs in most cases. However cava-filters in the inferior vena cava (IVC) are efficient for patients with contraindications to anticoagulant drugs, high risk of bleeding and frequent recurrence of DVT at the background of optimal mode of hypocoagulation [25]. One of the indications is identification of extensive floating thrombosis. The procedure is widely used despite of significant amount of undesirable complications (about 35 %) [26]. The described complications include displacement or migration of a cava-filter towards the cavity of the right ventricle, perforation of IVC with retroperitoneal hemorrhage, abdominal aorta wall perforated by the device, filter clotting, IVC clotting or clotting of approaches [27]. Some evident disadvantages of cava-filters are noted one year after implantation: chronical venous insufficiency in both extremities in 61 % of patients. Therefore, despite of high efficiency in prevention of thromboembolic complications, cava-filters are associated with development of significant number of complications at all stages of treatment. It supposes usage of cava-filters with adherence to the strict indications, for example, for patients with polytrauma. If a degree of an injury does not allow using anticoagulants, but, at the same time, floating thrombosis or events of pulmonary embolism are diagnosed, preventive implantation of cava-filters is the method of choice for prevention of development of fatal PE [28, 29].
During the recent years surgical prevention of pulmonary embolism is often made with implantation of temporary cava-filters for the period of correction of transient risk factors of venous thrombosis and disappearance of thrombotic situations relating to high risk of thrombembolia. Temporary cava-filters are placed up to 28 days (12-14 days at average). However such short period does not exclude complications. Strict adherence to indications for implantation of cava-filters and sufficient surgeon’s experience determine minimal risk of serious complications [30]. It is possible only in big trauma centers with available units of vascular surgery and radial endovascular equipment.
The alternative for cava-filters is surgical treatment of patients with thrombosis in IVC (IVC plication, intercrossing or ligation of magistral veins with absorbable suturing material, thrombectomy at the background of accelerated blood flow or without it). The proportion of thrombosis in IVC is more than 95 % of all venous thrombosis including 10 % of cases complicated by PE [31]. However treatment of thrombosis in IVC is not standardized yet. There is not any uniform opinion about multiple surgical techniques. The indications and the contraindications are often controversial.
First of all, it is associated with unpredictable outcomes of surgical interventions. If one of the deep femoral veins is crossed and the outcome is clear, venous outflow is partially compensated by means of collateral blood flow [32]. The result is not so clear in case of ligation of the femoral vein with use of suturing material (for example, Dexon, Vicryl), which absorbs 70-90 days and vein lumen is fully restored. The ultrasonic examination showed several types of changes 6 months after surgery [32]. For the first type, an outcome corresponds to the course of irreversible occlusive venous thrombosis in half of cases. A lumen in the distal segment of the superficial femoral vein restores because of absorption of a ligature. Later we observed recanalization in the place of thrombotic occlusion. It testified the fact that realization of thrombectomy from the popliteal-femoral segment with ligation of the superficial femoral vein removes occlusion and results in restoration of the lumen of the popliteal-femoral segment and, correspondingly, gives a possibility for normalizing blood flow in the venous segment.
The most favorable course is related to the second type of possible outcomes. All patients with satisfactory and almost full recanalization of veins do not have any clinical manifestations of venous insufficiency. A possibility of such outcome is possibly related to salvage of integrity of the vein during surgery and quick processes of recanalization after successful treatment. Unfortunately, the proportion of patients with such outcomes is only 12 % of all observed individuals.
The third type of changes in venous remodeling is considered as clinically unfavorable. Recanalization of the deep femoral vein is satisfactory, but this type is associated with fibrous transformation of walls and the valve unit of the deep femoral vein, which becomes a big collector making intense blood outflow. It results in stagnation in distal veins, dilatation of perforated veins and significant outflow. This type is significantly similar with the picture of post-thrombophlebitis syndrome, which develops in patients after common occlusive DVT without surgical intervention. However such unfavorable scenario was in only 7 % of the patients. About one-third of the patients demonstrate an intermediate type of restoration of venous blood flow. Further studies of morphofunctional state of a ligated vein are necessary for possibilities of more precise prediction of outcomes of surgery and choice of optimal measures of surgical treatment.
Therefore, the strategic tasks of surgical treatment of DVT are:
- restoration of patency in a clotted segment;
- prevention of development of pulmonary embolism;
- prevention of recurrent deep venous thrombosis;
- long term minimization of manifestations of chronical venous insufficiency [12].
We believe that it is necessary to continue to research and to implement the modern advanced methods of prevention and treatment of PE after injuries. Such studies will allow developing some clear recommendations and will remove unjustified variability. It will increase quality and will improve treatment of patients in traumatology and orthopedics.