QUALITY ASSURANCE OF HIGH-DOSE IV HEPARIN TREATMENT EXEMPLIFIED BY PATIENTS IMPLANTED WITH CORONARY PALMAZ-SCHATZ STENTS

The need to standardize treatment with high-dose IV standard heparin b y using activated partial thromboplastin time (APTT) reagents tested f or their heparin sensitivity and by establishing a standard treatment schedule led to the development of the ''Lainz concept'' of heparin ma nagement. The determination of heparin sensitivity of the 2 APTT reage nts used (APTT Micronized Silica and APTT Actin FSL), their good agree ment (r=.9977; P=.000), and their therapeutic APTT ratio of 1.5-2.5 fo ld of baseline APTT (therapeutic range, forty-five to seventy-five sec onds) equivalent to 0.3-0.7 antifactor Xa units are presented. The ''L ainz concept'' was tested in 29 patients receiving high-dose heparin a fter coronary artery stenting. A mean dose of 1,273 U of standard hepa rin/hour (15.7 U/kg body weight/hour) was shown to produce APTTs in th e therapeutic range. From the introduction of the ''Lainz concept'' 81 % of the APTTs were kept within the therapeutic range by using a defin ed heparin-monitoring schedule based on a guideline protocol for contr olling heparin treatment. Only 19% of the APTTs were below the therape utic range. Factors underlying subtherapeutic APTTs are discussed. The reduction in the rate of subtherapeutic APTTs to less than 3% seen af ter the introduction of the ''Lainz concept'' constitutes an important contribution toward quality assurance in high-dose heparin treatment.