[Acetylsalicylic acid (ASA) resistance in patients with ischemic heart disease (IHD) as bioindicator of the treatment strategy].
BACKGROUND
The interest in aspirin resistance has been increasing during the last few years, with researchers earnestly pursuing alternative anti-platelet therapies and devices for measuring platelet aggregation. The recent studies suggest that 5-45% of patients taking aspirin do not experience adequate anti-platelet effects.


RESULTS
There is scant evidence proving that aspirin resistance has some clinical consequences. To assess the prevalence of aspirin resistance in patients with ischemic heart disease (IHD) two independent methods were used: platelet aggregation in platelet rich plasma (PRP) after induction by propylgallate (CPG), and assessment of platelet function by PFA 100 method. The study population consisted of 424 patients treated for IHD on the 2nd Dept. of Medicine, Teaching Hospital, Hradec Kralove. The age, gender, diagnosis and effect of therapy were characterized in this group of the patients. Daily ASA dose was 100 mg. We used two methods to monitor ASA treatment efficacy: a) thrombocyte aggregation after induction by CPG, b) the assessment of platelet function by PFA 100 method. a) Of the patients studied by CPG platelet aggregation, 51 (12.1%) pts were resistant to ASA dose 100 mg/day, and 32 (7.6%) pts remained resistant even after increasig the dose to 200 mg/day. In 80 (20%) pts, the daily ASA dose of less than 100 mg was sufficient to inhibit platelet function. b) Although the PFA-100 system is not able to detect the difference between low and high ASA dose, we found 53 (15.2%) patients aspirin resistant using this method.


CONCLUSIONS
In the patients with IHD treated with 100 mg of ASA per day, our study has shown that the prevalence of aspirin resistance was 12.1% using CPG method, and 15.2% using PFA-100 method. Aspirin resistance was dose dependent. Prevalence of ASA resistance in patients treated with 200 mg of ASA per day was only 7.6% using the CPG method.
Malý
J
J
Katedra internich oborů LF UK a FN, Hradec Králové. maly@fnhk.cz
Pecka
M
M
Gregor
J
J
Dulícek
P
P
Blazek
M
M
Malý
R
R
Pudil
R
R
Bláha
M
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001241:Aspirin / Q000494:pharmacology / Q000627:therapeutic use*; D001792:Blood Platelets / Q000187:drug effects; D004351:Drug Resistance; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000097:blood / Q000188:drug therapy*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D010979:Platelet Function Tests
D010975:Platelet Aggregation Inhibitors; D001241:Aspirin