Isosorbide dinitrate inhibits platelet adhesion and aggregation in nonthrombolyzed patients with acute myocardial infarction.
BACKGROUND
Apart from their vasodilatatory properties, nitrates have been shown to inhibit platelet aggregation. The effects of nitrates on platelet adhesion have not been studied. Nonselected patients with acute myocardial infarction (AMI) have been suggested to gain no benefit from administration of nitrates. However, the importance of nitrates may be greater in a subgroup of nonthrombolyzed patients with AMI.


OBJECTIVE
Isosorbide dinitrate (ISDN) decreases platelet adhesion and aggregation in nonthrombolyzed patients with AMI.


METHODS
Consecutive 48 men with AMI, not eligible for thrombolytic therapy because of late presentation (> 12 h), were prospectively randomized 2:1 to double-blind ISDN (mean dose 2.4 +/- 0.9 mg/h) (n = 33) or placebo (0.9% sodium chloride) (n = 15) infusion. All patients received aspirin. Blood samples were taken at baseline (no study medication) and 3 h into ISDN or placebo infusion. Platelet adhesion to collagen was measured in the ethylene diamine tetraacetic acid (EDTA)-platelet rich plasma by recording changes in light transmission with an optical aggregometer. Platelet aggregation was measured using the Born's method.


RESULTS
Isosorbide dinitrate significantly decreased both platelet adhesion and aggregation. No effect was seen in the placebo group.


CONCLUSIONS
In patients with AMI who do not receive thrombolytic therapy, ISDN effectively inhibits platelet adhesion and aggregation. These effects of nitrates may be of therapeutic and prognostic significance in this group of patients.
Gebalska
J
J
Department of Cardiology, Postgraduate Medical School, Grochowski Hospital, Warsaw, Poland.
Wolk
R
R
Ceremuzynski
L
L
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001241:Aspirin / Q000627:therapeutic use; D016009:Chi-Square Distribution; D004311:Double-Blind Method; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D006801:Humans; D007548:Isosorbide Dinitrate / Q000494:pharmacology* / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000188:drug therapy*; D010919:Placebos; D010973:Platelet Adhesiveness / Q000187:drug effects*; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use; D010976:Platelet Count; D011446:Prospective Studies; D014665:Vasodilator Agents / Q000494:pharmacology* / Q000627:therapeutic use*
D005343:Fibrinolytic Agents; D010919:Placebos; D010975:Platelet Aggregation Inhibitors; D014665:Vasodilator Agents; D007548:Isosorbide Dinitrate; D001241:Aspirin