Prophylaxis against postoperative pulmonary embolism and deep-vein thrombosis by low-dose heparin

Intermittent pneumatic calf compression for prevention of deep venous thrombosis in general abdominal surgery

A prospective randomized trial is described in 119 patients undergoing major abdominal general surgical procedures. Half of the patients were treated prophylactically with intermittent pneumatic calf compression, begun after the induction of anesthesia and continued until the patient was walking; the other half acted as controls. Deep venous thrombosis was detected by iodine-125 fibrinogen scanning and confirmed by venography, and did not differ significantly in the control and treated groups. One fatal pulmonary embolism occurred in each group. The presence of malignancy of the gastrointestinal tract did not influence the results. The findings suggest that pneumatic compression delayed the development of deep venous thrombosis postoperatively and that perhaps it should be continued until discharge from hospital.

The effect of Ticlopidine upon platelet function, haemorrhage and post-operative thrombosis in patients undergoing suprapubic prostatectomy

In order to study in its protective effect against post-operative thrombosis, Ticlopidine was administered to one out of two randomized groups of patients undergoing suprapubic prostatectomy. Bleeding time, platelet function, and haematological parameters were followed. Blood loss during operation and post-operatively were estimated, transfusions required and subjective tolerance were recorded. Among twenty-six evaluated patients receiving Ticlopidine, positive leg scans were found in four, whereas among twenty patients treated with acenocoumarol post-operatively, positive leg scans were found in seven patients. The difference is not statistically significant, thus Ticlopidine appears to offer a protection against deep venous thrombosis comparable to that of acenocoumarol. A score is introduced for comparison of the results of aggregation tests. Platelet aggregability diminished during the use of the drug, but the adhesiveness was not influenced by Ticlopidine. The bleeding time was prolonged in both groups studied. Ticlopidine did not raise per-operative blood loss and caused only slightly more haematuria post-operatively. The subjective tolerance was good.

Thrombosis: the relationship of hemostatic mechanisms to drug therapy

The mechanism of action and present clinical role of drugs affecting hemostasis in the therapy of spontaneous, postoperative, and posttraumatic arterial thrombosis, arterial embolism, venous thrombosis, pulmonary embolism, and intracranial aneurysm have been reviewed. Both the management of neurosurgical problems and the development of antithrombotic regimens are improving. In regard to the use of drug therapy, discussed herein, each surgeon will reach his own decision based on his findings in the individual patient, and may wisely elect in specific situations not to employ drug therapy. The comments offered in ths analysis are to be construed as suggestions not mandates, as they will undoubtedly undergo modification with time. In closing, it is appropriate to recall a famous Chinese curse: "May you live," it reads, "in a time of transition."

Pulmonary thromboembolism. 2. New trends in prophylaxis and therapy

Although low-dose heparin therapy is the technique most commonly used for prophylaxis of pulmonary thromboembolism, its usefulness is being questioned. Platelet deaggregation prophylaxis with either aspirin or dipyridamole, or both, apparently is a reasonable alternative, but further studies are needed. For treatment of pulmonary thromboembolism, continuous conventional-dose heparin therapy is the approach of choice. It has the highest therapeutic/toxic ratio and is the most effective technique for prevention of clot propagation. The patient's fibrinolytic network must be intact, however, if clot degradation is to occur. Fibrinolytic therapy with urokinase or streptokinase should be restricted to use in patients with massive pulmonary embolism in whom hemodynamics are unstable. Caval interruption and pulmonary embolectomy have lower benefit/risk ratios than do the medical alternatives and are rarely used for pulmonary thromboembolism.

Incidences of fatal postoperative pulmonary embolism after prophylaxis with dextran 70 and low-dose heparin: an international multicentre study

A total of 4352 patients were admitted to a prospective' randomised multicentre trial comparing the prophylactic efficacy of dextran 70 and low-dose heparin against fatal pulmonary embolism after elective operations for general, orthopaedic, urological, and gynaecological conditions. Out of 3984 patients correctly admitted, 1993 were allocated to receive dextran 70 and 1991 to receive low-dose heparin. Withdrawal of prophylaxis because of bleeding or technical difficulties occurred more often in the heparin group, but allergic reactions were more common in the dextran group. Of the 75 patients who died within 30 days after operation, 38 had been given dextran and 37 low-dose heparin. Necropsy was performed in 33 and 32 of these cases respectively. In six patients in each group pulmonary embolism was the sole or a contributory cause of death. Of these, five patients in the dextran group and two in the heparin group had received a full course of prophylaxis. There was no statistically significant difference between the two treatment groups in the incidence of fatal pulmonary embolism after a full course of prophylaxis.

Postoperative deep vein thrombosis of the lower limb and prophylactic value of heparin evaluated by phlebography

The incidence of postoperative thrombosis of the leg at phlebography, and the prophylactic effect of low-dose heparin, was assessed in a double-blind investigation comprising 50 patients. Thrombosis occurred in 17 per cent in the heparin group and in 23 per cent in the placebo group. This difference is not significant. No prophylactic effect of low-dose heparin was demonstrated.