Aspirin nonsensitivity in patients with vascular disease: Assessment by light transmission aggregometry (aspirin nonsensitivity in vascular patients)

The associations of candidate gene polymorphisms with aspirin resistance in patients with ischemic disease: a meta-analysis

BACKGROUND

Recently, extensive research has been conducted on the relationship between aspirin gene polymorphisms and aspirin resistance (AR) in patients with ischemic diseases. Among the numerous candidate genes, it remains unclear which ones are significantly associated with AR and could potentially serve as potential biomarkers for genetic testing before aspirin use.

METHODS

Eligible articles were searched in PubMed, Embase, Cochrane Library, WanFang, CNKI and Sinomed. A cohort study examining the efficacy of aspirin in secondary prevention for patients with ischemic diseases, along with a discussion on genetic polymorphisms and their association with AR, has been included. The Newcastle-Ottawa Scale for assessing the quality of included studies. Odds ratios (OR) with 95% confidence intervals (CI) were used as measures of effect. Subgroup analyses were conducted based on different genotypes with the same genetic polymorphisms, different research regions and types of ischemic diseases.

RESULTS

From 75 eligible articles, 94 candidate gene polymorphisms were analyzed. In the overall analysis, 25 genes were subjected to meta-analysis and 69 genes were systematically described. 23 gene polymorphisms were observed to be significantly associated with AR, including PTGS2(rs20417) (OR = 0.57, 95% CI: 0.44-0.73), ITGA2(rs1126643) (OR = 0.52, 95% CI: 0.29-0.93), and TbXA2R(rs1131882) (OR = 1.54, 95% CI: 1.09-2.18) were obtained from the combined analysis of this study, and 20 genes were systematically described in this study. Further subgroup analyses demonstrated that AA genotype for PTGS1(rs1330344) (OR = 0.56, 95%CI:0.43-0.74), C allele for PTGS1(rs5788) (OR = 0.51, 95%CI: 0.30-0.87) polymorphisms were significantly associated with AR. The polymorphisms of 13 genes, including PTGS1(rs1236913), have been studied only in Asia, GP6(rs1613662) has been studied only in Europe, and the polymorphisms of 5 genes, including ABCB1(rs1045642), showed different correlations with AR in various regions. The individuals with the PTGS1 (rs5788) variant who experienced an ischemic stroke (OR = 0.98, 95%CI: 0.54-1.67) may exhibit an elevated risk of AR compared to those with coronary artery disease (OR = 0.51, 95%CI: 0.3-0.87).

CONCLUSIONS

Our meta-analysis indicates that PTGS2(rs20417), ITGA2(rs1126643), and TbXA2R(rs1131882) could be potential genetic biomarkers for AR. Among these, PTGS2 (rs20417) is particularly suggested for individuals in Asia with ischemic diseases before aspirin use, as the GC/CC genotype raises AR risk by 42% compared to GG. ITGA2 (rs1126643) increases AR risk by 48% in Asia with the TC/TC genotype versus CC. However, results for ABCB1(rs1045642) and GP1BA(rs2243093) vary by regions, requiring further research.

Total Thrombus-Formation System in Patients with Peripheral Artery Disease

The Total Thrombus-formation Analysis System (T-TAS) is an automated device using coated microchips to assess thrombus formation under flow conditions. Its value to monitor coagulation function in patients under antiplatelet therapy awaits further clarification. This study evaluated T-TAS to detect response to dual antiplatelet therapy (DAPT) in patients with peripheral artery disease (PAD).T-TAS using the platelet-chip (PL-chip) and atheroma-chip (AR-chip) was performed in 60 patients with PAD on the day after lower extremity revascularization. Results were compared with light transmission aggregometry (LTA) and multiple electrode aggregometry (MEA, ADP- and ASPI-test). To determine T-TAS reference ranges, 30 healthy blood donors were enrolled.The area under the curve of the PL-chip (AUC-PL) was outside the reference range in 91.2% and AUC-AR in 21.1% of the PAD patients. Low responders in MEA ASPI, MEA ADP or both tests and low responders in LTA induced by ADP had a significantly higher AUC-PL compared to responders (204 vs 70, p = .016 and 140 vs 32, p < .001), respectively. Median AUC-PL in low responders in LTA and MEA, LTA or MEA and in responders in LTA and MEA was 301, 104 and 32 (p = .001), respectively. Our results suggest that the PL-chip can continuously assess the level of response to DAPT and might be helpful to monitor PAD patients.

Plasma complement component C2: a potential biomarker for predicting abdominal aortic aneurysm related complications

Blood-based adjunctive measures that can reliably predict abdominal aortic aneurysm (AAA)-related complications hold promise for mitigating the AAA disease burden. In this pilot study, we sought to evaluate the prognostic performance of complement factors in predicting AAA-related clinical outcomes. We recruited consecutive AAA patients (n = 75) and non-AAA patients (n = 75) presenting to St. Michael's Hospital. Plasma levels of complement proteins were assessed at baseline, as well as prospectively measured regularly over a period of 2 years. The primary outcome was the incidence of rapidly progressing AAA (i.e. aortic expansion), defined as change in AAA diameter by either 0.5 cm in 6 months, or 1 cm in 12 months. Secondary outcomes included incidence of major adverse aortic events (MAAE) and major adverse cardiovascular events (MACE). All study outcomes (AAA diameter, MACE and MAAE) were obtained during follow-up. Multivariable adjusted Cox regression analyses were performed to assess the prognostic value of plasma C2 levels in patients with AAA regarding rapid aortic expansion and MAAE and MACE. Event-free survival rates of both groups were also compared. Compared to non-AAA patients, patients with AAA demonstrated significantly higher plasma concentrations of C1q, C4, Factor B, Factor H and Factor D, and significantly lower plasma concentrations of C2, C3, and C4b (p = 0.001). After a median of 24 months from initial baseline measurements, C2 was determined as the strongest predictor of rapid aortic expansion (HR 0.10, p = 0.040), MAAE (HR 0.09, p = 0.001) and MACE (HR 0.14, p = 0.011). Based on the data from the survival analysis, higher levels of C2 at admission in patients with AAA predicted greater risk for rapid aortic expansion and MAAE (not MACE). Plasma C2 has the potential to be a biomarker for predicting rapid aortic expansion, MAAE, and the eventual need for an aortic intervention in AAA patients.

Aspirin Resistance in Vascular Disease: A Review Highlighting the Critical Need for Improved Point-of-Care Testing and Personalized Therapy

Aspirin resistance describes a phenomenon where patients receiving aspirin therapy do not respond favorably to treatment, and is categorized by continued incidence of adverse cardiovascular events and/or the lack of reduced platelet reactivity. Studies demonstrate that one in four patients with vascular disease are resistant to aspirin therapy, placing them at an almost four-fold increased risk of major adverse limb and adverse cardiovascular events. Despite the increased cardiovascular risk incurred by aspirin resistant patients, strategies to diagnose or overcome this resistance are yet to be clinically validated and integrated. Currently, five unique laboratory assays have shown promise for aspirin resistance testing: Light transmission aggregometry, Platelet Function Analyzer-100, Thromboelastography, Verify Now, and Platelet Works. Newer antiplatelet therapies such as Plavix and Ticagrelor have been tested as an alternative to overcome aspirin resistance (used both in combination with aspirin and alone) but have not proven to be superior to aspirin alone. A recent breakthrough discovery has demonstrated that rivaroxaban, an anticoagulant which functions by inhibiting active Factor X when taken in combination with aspirin, improves outcomes in patients with vascular disease. Current studies are determining how this new regime may benefit those who are considered aspirin resistant.

Low-dose aspirin and rivaroxaban combination therapy to overcome aspirin non-sensitivity in patients with vascular disease

Approximately 20% of vascular patients treated with acetyl salicylic acid (i.e., aspirin) demonstrate less than expected platelet inhibition – putting them at a four-fold increased risk of adverse cardiovascular events. Low-dose rivaroxaban (2.5 mg twice daily) in combination with low-dose aspirin has been shown to reduce adverse cardiovascular and limb events when compared to aspirin alone. In this study, light transmission aggregometry was used to measure arachidonic acid-induced platelet aggregation to evaluate the potential of combining low-dose rivaroxaban and aspirin in attenuating or overcoming aspirin non-sensitivity. In the discovery phase, 83 patients with peripheral arterial disease (PAD) taking 81 mg aspirin daily were recruited from the outpatient vascular surgery clinic at St Michael's Hospital between January to September 2021. 19 (23%) were determined to be non-sensitive to aspirin. After ex-vivo addition of 2.5 mg dosage equivalent of rivaroxaban, aspirin non-sensitivity was overcome in 11 (58%) of these 19 patients. In the validation phase, 58 patients with cardiovascular risk factors who were not previously prescribed aspirin were recruited. In this group, ex-vivo addition of 2.5 mg dosage equivalent of rivaroxaban significantly reduced arachidonic acid-induced platelet aggregation in the presence of aspirin. These results demonstrate the potential for low-dose rivaroxaban to overcome aspirin non-sensitivity in patients with PAD. Further studies are needed to evaluate and confirm these findings.