[Incidence of postoperative deep vein thrombosis in general surgical and urological patients an investigation by means of the 125I-Fibrinogen test in 95 patients withoug prophylaxis (author's transl)]

Venous thromboembolism after surgery for benign prostatic hyperplasia

A systematic review has been performed on venous thromboembolism after surgery for benign prostatic hyperplasia. The risk of deep vein thrombosis is two to four times higher after open surgery than after transurethral resection. The risk after the newer transurethral methods (laser, radiofrequency, heat) is not known. Specific studies on thromboprophylaxis are few and have limited numbers of patients. Nonetheless, thromboprophylaxis (heparin) reduces the frequency of postoperative deep vein thrombosis after open surgery. Studies on patients undergoing transurethral resection are lacking. Antifibrinolytic treatment to diminish bleeding does not seem to increase the risk of thrombosis.

[Stationary thromboprophylaxis in casualty surgery. Relevance of postoperative mobility and preexisting risk factors]

The presented thromboprophylactic concept includes weight bearing and ankle motion as well as breathing therapy and drug prophylaxis (antiphlogistics, analgesic drugs, heparin). Routinely performed ultrasound screening of the deep veins (legs and pelvis) before release showed a low DVT incidence of 2.5% in a prospective clinical observation of 841 inpatients. Obesity, venous insufficiency, and a history of previous thromboembolic events were associated with a significantly increased risk of thrombosis (relative risk 4.1, 4,9, and 5.8, respectively) The duration of immobilization also had a relevant influence indicating that early postoperative physiotherapy in traumatology and orthopedic surgery has a widely underestimated thromboprophylactic effect.

Thromboembolic problems in colorectal cancer surgery

The problem of thromboembolic complication in patients undergoing surgery for colorectal malignancies has been evaluated based on data from the literature and own experiences. One problem is the few studies dealing exclusively with this group of patients or presenting separate data on these patients. Deep vein thrombosis is somewhat more common than that seen after other types of abdominal surgery. No difference between patients operated on for colonic or rectal cancer have been found. The number of fatal or contributory pulmonary emboli is higher than the average number among other operated patients. Low dose heparin, low molecular weight heparin and mechanical methods, especially when combined with heparin or dextran, reduce the frequency of deep vein thrombosis. Fatal pulmonary embolism can effectively be prevented by low dose heparin with or without dihydroergotamine or by dextran.

Hemorheology in surgery--a review

The rheological behavior of blood and its components under physiologic and pathophysiologic conditions is reviewed, with a focus on the type and extent of pathohemorheological changes in surgical patients during hospitalization and thereafter, as well as their clinical consequences with regard to thromboembolic complications. During the operation and the postoperative period various hemorheological and hemostasiological alterations acquire clinical significance: 1. hyperreagibility of platelets with increased aggregation and adhesion tendency 2. changes in fibrinogen, albumin, and globulin concentrations, which affect viscosity and red cell aggregation 3. impairment of red cell deformability 4. increase in clotting factors 5. disturbance of fibrinolysis characterized by diminution of plasmatic plasmin and increase in antiplasmin activity In addition, anesthetic techniques have also been shown to affect hemorheological and hemostasiological parameters. The complex pattern of pathohemorheological and hemostasiological changes shows that thromboembolism in the course of surgical interventions is provoked by multifactorial disorders. Thrombosis prevention should, therefore, counteract both hemorheological and hemostasiological disturbances. Since pathohemorheological and pathohemostasiological changes are already detectable before, and increase during operation, preventive measures should start before the surgical intervention to obtain maximum benefit. Therapeutic possibilities for the avoidance of these multifactorial disturbances are discussed with particular reference to pentoxifylline, which satisfies the complex requirements of a hemorheologically and hemostasiologically active therapeutic agent.

Does peroperative external pneumatic leg muscle compression prevent post-operative venous thrombosis in neurosurgery?

Post-operative deep venous thrombosis (DVT) is a frequent and potentially life-threatening complication in neurosurgery. In this field of surgery, with its special demands for exact haemostasis, prophylaxis against deep venous thrombosis with anticoagulant drugs has been utilized only reluctantly. Postoperative pneumatic muscle compression (EPC) has been shown to be effective, although there are several practical considerations involved with this method which limit its clinical applicability. In the present study per-operative EPC was evaluated and was found to provide good protection against DVT in patients with increased risk from this complication. This method has the advantage of being effective, safe, inexpensive and readily practicable.

Low molecular weight heparin once daily compared with conventional low-dose heparin twice daily. A prospective double-blind multicentre trial on prevention of postoperative thrombosis

In a randomized, prospective, double-blind multicentre trial, the effect of conventional low-dose heparin 5000 units twice daily, was compared with that of a low molecular weight heparin fragment (4000-5000) 5000 anti-factor Xa units once daily. Four hundred and thirty-two patients fulfilled the inclusion criteria and were analysed for development of deep vein thrombosis (125I-labelled fibrinogen test) and haemorrhagic complications. Thrombosis occurred in a 4.3 per cent of patients in the low-dose heparin group and in 6.4 per cent of patients in the heparin fragment group, a difference which is not significant. There was a significant delay in the onset of thrombosis in the heparin fragment group. Mortality did not differ between the groups, nor did peroperative blood loss or transfusion requirements or infectious complications. Haemorrhagic complications occurred significantly more often in the fragment group (11.6 per cent) than in the conventional heparin group (4.6 per cent). Patients in the heparin fragment group experienced local pain following the subcutaneous injection significantly less often.

A comparative study of Dextran 70 and a sulphated polysaccharide in the prevention of postoperative thromboembolic complications

A prospective randomized study has been performed, comparing a semisynthetic polysulphated xylan of vegetable origin (mol. wt approximately 4000) with Dextran 70 as prophylactic agent against postoperative thromboembolic complications following elective abdominal surgery. A total of 109 patients entered the trial and the analysis after exclusions is based on 86 patients. The overall frequency of 125I-labelled fibrinogen test-detected thrombosis was 2.9 per cent in the polysaccharide group against 19.2 per cent in the Dextran 70 group (P less than 0.05). There was no difference in haemorrhage or different complications.