We greatly enjoyed reading the article by Kershaw and colleagues,1 as well as the study by Elliot et al,2 each describing successful methods of standardizing heparin therapy in the treatment of deep venous thrombosis. Kershaw and colleagues1 expressed interest in a success rate analysis from our study3 on the weight-based heparin nomogram that appeared in a tabular form in our original article.
From among 62 patients randomized to treatment with the weight-based nomogram, 444 activated partial thromboplastin time (aPTT) values were obtained within 48 hours of initiation of heparin therapy. We found that 17% (77/444) of our aPTTs were subtherapeutic, 65% (288/444) were therapeutic, and 18% (79/444) were supratherapeutic. Thus, our nomogram was identically successful to computer-assisted dosing in maintaining aPTT values above the therapeutic threshold (83% of the time). We were slightly less successful in avoiding supratherapeutic aPTTs, however our definition of therapeutic range (an