Background: Chronic renal failure (CRF) is associated with increased risk of cardiovascular morbidity and mortality. There are reports of increased rates of aspirin resistance in these patients, which may worsen clinical prognosis. The aim of this study was to explore the prevalence of aspirin resistance in CRF.
Methods: Forty three patients undergoing chronic hemodialysis (average age- 66.8±8.6, 40.1% female, 47.3% diabetics) were compared to 463 patients with normal renal function who have undergone percutaneous coronary intervention (average age- 67.1±10.4, 17.9% female, 38.6% diabetics). All subjects were taking aspirin regularly, at a dosage of 75-100mg. Aspirin responsiveness was determined by the VerifyNow Aspirin Assay. Resistance to aspirin was defined as aspirin reaction unit (ARU) ≥550. A secondary analysis, according to the alternative cut-off of ARU≥520, was also performed.
Results: Mean ARU was higher in CRF patients (531.9±67.8 vs. 441.7±54.6, p<0.001). The frequency of aspirin resistance was significantly higher in the CRF group compared with patients with normal renal function, both according to the ARU cut-off of 550 (30.2% vs. 4.8%, p<0.001) and 520 (55.8% vs. 8.6%, p<0.001).
Conclusion: Patients with CRF have a lower responsiveness to aspirin, as well as a higher frequency of aspirin resistance. This might further increase the risk of cardiovascular morbidity and mortality in these patients.
