[Biological modifications induced by 3 low molecular weight heparins, PK 10169, Kabi 2165 and CY 216, compared to unfractionated heparin injected subcutaneously in healthy subjects in general surgery and in aged subjects in internal medicine].

Activities of anti-Xaam, anti-IIaam, Heptest and calcium thrombin time (Ca TT) were compared in: 12 male healthy volunteers after increasing doses of 20, 40, 60 and 80 mg/day of Enoxaparine; 76 patients after gynecological surgery treated with 20 mg (12 cases), 40 mg (15 cases) or 60 mg (10 cases) per day of Enoxaparine versus calcium heparin as 5,000 IU x 3/day (39 cases); 68 patients after general surgery treated with 2,500 units Fragmine/day (34 cases) versus calcium heparin 5,000 IU x 2/day (34 cases); 27 patients in a medical ward treated with either 7,500 Choay Institute units/day of Fraxiparine (14 cases) or Cutheparine (magnesium heparinate) (13 cases). In this latter case results of Heptest only are reported. In healthy volunteers and patients after gynecological operations, the Ca TT and anti-IIaam activity were significantly modified after doses greater than or equal to 40 mg. Values for anti-Xaam and anti-IIaam were dose-related but higher in healthy volunteers. The anti-Xa/anti-IIa ratio was 3-4. Correlation between Heptest, a simple test, and anti-Xa activity--both very good markers of low molecular weight heparins (LMWH)--was very good (r = 0.93, p less than 0.02 in healthy volunteers; r = 0.87, p less than 0.01 in operated patients). Peak activity was at about 3 to 4 hours after injection, the half-life of anti-Xa and anti-IIa activities being 4 and 2 hours respectively. After heparin injection, the anti-Xa/anti-IIa ratio was 1 but activities were weak (5,000 IU x 2 = 0.02 +/- 0.02), a little higher with 5,000 IU x 3 (0.05 +/- 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)