Heparin administration via nomogram versus a standard approach in venous and arterial thromboembolic disease.
To determine whether heparin administered by continuous intravenous infusion using a nomogram is superior to a random dosing scheme, we performed a prospective, randomized comparative trial in 161 patients. Patients were prospectively randomized to one of three groups. Group I received an intravenous bolus of 5000 IU of heparin followed by heparin administration according to a modification of a previously published nomogram. Group II patients received a 5000 IU intravenous bolus of heparin followed by continuous intravenous heparin infusion with dosage adjustment at the discretion of the treating physician. Group III patients received a continuous intravenous heparin infusion with dosage adjustments at the discretion of the treating physician without the prior administration of a bolus dose. Activated partial thromboplastin time (APTT) was obtained at baseline, 6 h after each heparin dose adjustment and every morning. The mean percent of each patient's APTTs in the subtherapeutic range (< 50 sec) over the course of treatment was 9% for group I and 24% for groups II and III, p = 0.0001. The three groups had a similar percentage of each patient's APTTs within the therapeutic range (50-80 sec). There was a larger percentage of APTTs > 80 sec in group I (46%) compared to group II (31%) or group III (32%), p = 0.01. There were no clinically recurrent deep venous thrombi or arterial thromboemboli in any of the groups. Two patients had documented pulmonary emboli during heparin therapy (one in group I; one in group II). There was no difference in the complication rates of heparin therapy or the need for blood transfusions among the three groups. Patients randomized to the heparin nomogram (group I) achieved an APTT > 50 sec more frequently than patients in the other two groups. Overall, fewer patients in the nomogram group were subtherapeutic, and, when APTT levels fell in the subtherapeutic range, the nomogram restored APTTs to the therapeutic range faster than the standard methods. The heparin nomogram was clearly more effective as a method of heparin dosing than standard methods of anticoagulation dosing.