COX-1, COX-2 and CYP2C19 variations may be related to cardiovascular events due to acetylsalicylic acid resistance

BACKGROUND

In some stent implanted patients, cardiovascular events (CE) may occur. Acetylsalicylic acid (ASA) is routinely administered to these patients in order to prevent the occurrence of CE. CE may be related to gene variations which cause ASA resistance (AR). Therefore, it was aimed to investigate the relationship between COX-1, COX-2, CYP2C9 and CYP2C19 variations with CE due to AR.

MATERIALS AND RESULTS

Seventy-four stent implanted patients, using 100 mg of ASA per day during five years were enrolled into the study. Following stent implantation, thirty-eight patients who had a CE within five years due to AR and 36 patients without CE were enrolled in patient and control group, respectively. AR was confirmed by platelet aggregation testing. After DNA isolation from blood; COX-1, COX-2, CYP2C19 and CYP2C9 variations were investigated with real-time polymerase chain reaction. At the end of this study, heterozygous genotype of COX-1 was found statistically high in patients whereas heterozygous genotype of CYP2C19*17 was found statistically high in controls. The presence of C and G allele in COX-1 and COX-2 were found statistically high in patients, respectively. The presence of T allele in CYP2C19*17 was found statistically high in controls. Heterozygous genotype of COX-1 variation was found statistically high in patients who have AR. Additionally heterozygous genotype of CYP2C19*17 was found statistically high in patients who have low thrombosis risk.

CONCLUSIONS

COX-1 and COX-2 gene mutations may increase the risk of CE due to AR whereas CYP2C19*17 may have a protective effect in this process.

Platelet function assays for the diagnosis of aspirin resistance

Aspirin, an antiplatelet drug, is commonly used at low doses for numerous indications, including prophylaxis of cardiovascular, neurovascular, and venous thromboembolic events. Due to review articles suggesting that aspirin resistance may result in poorer outcomes, interest in assessing platelet function is increasing. Despite this, platelet function tests are rarely used as part of routine clinical practice and therefore, a basic understanding of these tests may be lacking. Although aspirin resistance can be categorized as clinical or laboratory resistance, determining laboratory resistance is the only way to determine resistance before treatment failure occurs. Therefore, knowledge of platelet assays to determine aspirin resistance is of importance. The following review aims to provide a framework for clinicians to understand the main principles of platelet function tests. This includes comparison of the most frequently used platelet assays to diagnose aspirin resistance, including the basic mechanism, methodology, reference ranges, inter-assay comparison, and their respective clinical considerations when using.

Association of Aspirin Resistance with Increased Mortality in Ischemic Stroke

OBJECTIVE

To investigate the association of aspirin resistance (AR) with mortality in a cohort of Chinese patients with acute ischemic stroke (AIS).

METHODS

One hundred and ninety-six ischemic stroke patients who received at least 7 days of aspirin therapy prior to stroke onset were enrolled. The outcome measure was all-cause and cardiovascular disease (CVD) mortality at 1-year follow-up. The relation of AR with the two end points was investigated with the use of logistic regression models.

RESULTS

The median age of included patients was 65(IQR, 56-76) years and 82(41.8%) were female. Thirty-five patients were defined as AR; thus, the rate was 17.9% (95%CI, 12.5% to 23.2%). The median NIHSS score was significantly higher in patients with AR than those with AS [12 (IQR, 10-17) vs. 7 (IQR, 4-10); Z=5.188; P<0.001]. Similarly, the median infarct volume was also significantly higher in AR than in AS [18.8 (IQR, 4.3-25.2) ml vs. 13.2 (IQR, 3.3-18.7) ml; Z=3.322; P=0.008]. During follow-up there were 43 patients (21.9%) died, including 24 CVD mortality (12.2%). In univariate logistic regression analysis, we found that the rate of all-cause mortality and CVD mortality increased by 390% (OR=4.90; 95%CI:2.24-10.75) and 422% (OR=5.22; 95%CI, 2.10-12.98) in AR group. After adjusting for all other significant predictors, AR still associated with high mortality and the rate of all-cause mortality and CVD mortality increased by 215% (OR=3.15; 95%CI:1.88-4.93) and 231% (OR=3.31; 95%CI, 1.96-522), respectively.

CONCLUSIONS

The present study shows that AR was a useful prognostic marker of all-cause or CVD mortality in Chinese patients with AIS.