Acetylsalicylic acid, low dose heparin, and a combination of both substances in the prevention of postoperative thromboembolism. A double blind study

[Prevention of thromboembolism in para-articular femoral fractures of the hip--results of a prospective randomized study of heparin-DHE and ASS-DHE]

The effectiveness of prophylaxis of thromboembolism either by acetyl-salicylic-acid (ASA) 0.5 g + dihydroergotamin (DHE) 2.5 mg three times a day or by Heparin 5000 IU + 0.5 mg DHE (HDHE) three times a day was compared in 404 patients, elder than 55 years, with fractures close by the hip joint. Effectiveness was proved daily clinical controls, perfusion scintigraphy on the day after admission, the fourth postoperative day and the day before discharge and by autopsy of the died patients. Clinical manifest thrombosis were seen on the operated legs in the HDHE-group in 7.6% of the patients, in ASA-DHE-group in 15.6%, on the not operated leg under prophylaxis by HDHE in 3.8%, by ASA-DHE in 4.1% of the patients. Increased postoperative bleeding could be found under HDHE in 16.1% of the patients, under ASA-DHE in 9.3% of the patients, wound haematoma in 9.5% under HDHE and in 5.7% of the patients of the ASA-DHE-group. Superficial wound infections occurred under HDHE in 8.1%, under ASA-DHE in 5.7% of the patients, deep infections under HDHE in 0.5% and under ASA-DHE in 1.6% of the patients. Gastrointestinal bleeding under HDHE in 0.5% of the cases and under ASA-DHE in 3.1% of the cases. Prophylaxis had to be discharged in 7.6% of the patients of the HDHE-group and of 19.7% of the ASA-DHE-group. Pathologic perfusion scars should be found in 54.0% of the patients of the HDHE-group and in 54.9% of the ASA-DHE-group. Pulmonal perfusion became worse despite of prophylaxis by HDHE in 15.6% of the cases and despite prophylaxis with ASA-DHE in 17.6%. Pulmonal perfusion became better under HDHE in 11.9% and under ASA-DHE in 12.4% of the cases. The mortality was 9.7%. Fatal thromboembolism occurred under HDHE in three patients (1.4%) and under ASA-DHE in three patients too (1.6%), after subcapital fractures in 0.5%, after pertrochanteric fractures in 2.1% and after subtrochanteric fractures in 6.25% of the patients without any significant difference between the two groups of prophylaxis. Fatal gastrointestinal bleeding had to be remarked in 1.0% of the patients of the HDHE-group and in 2.1% of the ASA-DHE-group, fatal infections in 0.5% of the patients of the HDHE-group and in 1.6% of the ASA-DHE-group. Fatal cardinal infarction could be seen under HDHE in 1.9% of the patients, under ASA-DHE no fatal cardial infarction occurred.(ABSTRACT TRUNCATED AT 400 WORDS)

Prevention of venous thromboembolism in general surgical patients. Results of meta-analysis

The results of randomized clinical trials evaluating commonly used methods of deep vein thrombosis (DVT) prophylaxis in moderate- and high-risk general surgery patients were pooled to obtain an unbiased estimate of efficacy and risks. Low-dose heparin (LDH), dextran, heparin-dihydroergotamine (HDHE), intermittent pneumatic compression (IPC), and graded elastic stockings significantly reduced the incidence of DVT; aspirin was ineffective. In contrast to other methods, elastic stockings have not been adequately studied to determine their value in reducing DVT in high-risk patients, such as those with malignancy. Only LDH and dextran were studied in numbers of patients sufficient for demonstrating a clear reduction in pulmonary embolism (PE). In comparison studies, LDH was superior to dextran in preventing DVT, but the two agents were equivalent in protecting against PE. Although HDHE was marginally better than LDH in preventing DVT, it appeared to have no advantage in preventing PE--at least in moderate-risk patients. The incidence of major hemorrhage was not increased with any of the prophylactic agents. However, wound hematomas occurred significantly more frequently with LDH, an effect noted in the pooled data from double-blind and open trials. In comparison trials with LDH, both dextran and HDHE had significantly fewer wound hematomas. LDH administered every 8 hours appeared more effective in reducing DVT than LDH administered every 12 hours; the incidence of wound hematomas was equivalent with both regimens.

Clinical pharmacology studies with indobufen (K 3920): inhibitor of platelet aggregation

When given to 12 subjects at single oral doses of 100 and 300 mg, indobufen caused clear-cut, dose-dependent, reversible inhibition of epinephrine- and collagen-induced platelet aggregation. Platelet factor 3 availability and platelet factor 4 release were not affected by the lower dose but were markedly reduced by the 300-mg dose. Bleeding time was slightly influenced by 100 mg, and 300 mg had a more pronounced effect. Indobufen 300 mg was also intravenously injected to five subjects. When washed platelets obtained before indobufen were resuspended in plasma obtained after indobufen, aggregation was inhibited. This was not the case when washed platelets obtained after indobufen were resuspended in plasma obtained before indobufen. These experiments indicate tha indobufen causes reversible inhibition of platelet functions unlike the effect of acetylsalicylic acid.

[Effect of heparin and ASA on changes of haemostasis induced by venous occlusion (author's transl)]

The influence of venous occlusion on plasmatic coagulation, on platelets, and on fibrinolysis was examined. After occlusion, activated factors XI and X could be demonstrated. Simultaneously, platelet aggregation induced by both collagen and epinephrine was increased. Fibrinolysis was found to be moderately enhanced. In patients taking acetylsalicylic acid (ASA), platelet functions were not altered by occlusion but the activation of plasmatic clotting factors was not influenced. Low dose heparin inhibited plasmatic activation but had no influence on the increase of platelet activities. By simultaneous administration of both substances, an additive effect was observed resulting in inhibition of plasmatic and platelet activation due to venous occlusion.