Heparin Resistance During and Post-Intravenous Nitroglycerin Infusion

Nitroglycerin has been reported to reduce activated partial thromboplastin time(aptt) values in patients treated with concurrent heparin and nitroglycerin. however,studies have yielded conflicting results. to determine whether intravenousnitroglycerin alters the anticoagulant effect of heparin, we prospectively evaluatedtwenty patients admitted for coronary angioplasty by measuring their aptt bothbefore initiation and after addition of nitroglycerin to heparin therapy. the resultsshowed that the mean of aptt at the baseline when patients were on heparin alonewas not significantly different from aptt measured upon addition of nitroglycerin,and 30 min following the cessation of nitroglycerin infusion, when patients werestill on the same dose of heparin. therefore, no direct effect of nitroglycerin on theanticoagulant effect of heparin was observed in this study.