Diabetes mellitus, glucose control parameters and platelet reactivity in ticagrelor treated patients

Prognostic Impact of Drug-Coated Balloons in Patients With Diabetes Mellitus: A Propensity-Matched Study

Patients with diabetes mellitus (DM) are at higher risk of restenosis and stent thrombosis after percutaneous coronary intervention (PCI) and drug-eluting stent (DES) positioning. Whether drug-coated balloons (DCB) can offer any benefit in this subset of patients has been seldom cleared out and was the aim of the present propensity-matched cohort study, that compared the prognostic impact of DCB versus DES in patients with DM who underwent PCI. Patients with DM enrolled in the NOvara-BIella-TREnto (NOBITRE) Registry were identified and matched according to propensity score, to a control population of patients with DM treated with DES. The primary study end point was the occurrence of major adverse cardiovascular events (MACEs). A total of 150 patients were identified in the DCB group and matched with 150 DES-treated patients. Patients treated with DCB displayed more often a previous cardiovascular history and received a more complete pharmacological therapy. Target vessel diameter and the percentage of stenosis were lower in patients with DCB, whereas binary in-stent restenosis was more common (p <0.001, p = 0.003, and p <0.001, respectively). Paclitaxel-eluting balloon represented the most common strategy in the DCB group, whereas Zotarolimus-eluting stents were used in half of the DES population. At a median follow-up of 545.5 days, MACE occurred in 54 (19.4%) of patients, with no difference according to the PCI strategy (21.6% vs 17.3%, adjusted hazard ratio [95% confidence interval] 1.51 [0.46 to 4.93], p = 0.50). Major ischemic end points were slightly increased in patients treated with DCB, whereas overall death was significantly reduced (3.6% vs 10.9%; adjusted hazard ratio [95% confidence interval] 0.27 [0.08 to 0.91], p = 0.03). In conclusion, the present propensity-matched study shows that, in patients with DM who underwent PCI for in-stent restenosis or de novo lesions, the use of DCB is associated with a similar rate of MACE and a modest increase in target lesion failure, but a significantly improved survival as compared with DES.

Platelets and the Atherosclerotic Process: An Overview of New Markers of Platelet Activation and Reactivity, and Their Implications in Primary and Secondary Prevention

The key role played by platelets in the atherosclerosis physiopathology, especially in the acute setting, is ascertained: they are the main actors during thrombus formation and, thus, one of the major investigated elements related to atherothrombotic process involving coronary arteries. Platelets have been studied from different points of view, according with the technology advances and the improvement in the hemostasis knowledge achieved in the last years. Morphology and reactivity constitute the first aspects investigated related to platelets with a significant body of evidence published linking a number of their values and markers to coronary artery disease and cardiovascular events. Recently, the impact of genetics on platelet activation has been explored with promising findings as additional instrument for patient risk stratification; however, this deserves further confirmations. Moreover, the interplay between immune system and platelets has been partially elucidated in the last years, providing intriguing elements that will be basic components for future research to better understand platelet regulation and improve cardiovascular outcome of patients.

Association of ADP-Induced Whole-Blood Platelet Aggregation with Serum Low-Density Lipoprotein Cholesterol in Patients with Coronary Artery Disease When Receiving Maintenance Ticagrelor-Based Dual Antiplatelet Therapy

The degree of platelet inhibition in patients undergoing dual antiplatelet therapy (DAPT) affects cardiovascular outcomes after acute coronary syndromes (ACS) and/or percutaneous coronary intervention. Our aim was to search for correlates of residual ex vivo platelet reactivity and circulating soluble P-selectin (sP-selectin), an index of in vivo platelet activation, in patients being treated by DAPT with ticagrelor. Adenosine diphosphate (ADP)-induced platelet aggregability (by multiple electrode aggregometry) and plasma sP-selectin were estimated in 62 stable post-ACS subjects (46 men and 16 women; mean age: 64 ± 10 years; 30 with type 2 diabetes (T2DM)) undergoing maintenance DAPT with ticagrelor and aspirin. These patients did not exhibit heart failure or other relevant coexistent diseases except for properly controlled T2DM, mild renal insufficiency, and hypertension. We also assessed this in 64 subjects on clopidogrel-based DAPT matched for age, sex, and T2DM status. ADP-induced platelet aggregation was below the optimal levels (190-460 arbitrary units (AU) * min) in most patients receiving ticagrelor-based DAPT, especially in those with below-median (<1.9 mmol/L) serum concentrations of low-density lipoprotein cholesterol (LDL-c) (128 ± 61 vs. 167 ± 73 AU * min for below-median and above-median LDL-c, respectively, p = 0.025). In contrast, platelet reactivity did not differ by LDL-c on clopidogrel-based DAPT (246 ± 101 vs. 268 ± 108 AU * min for below-median and above-median LDL-c, respectively, p > 0.4). Plasma sP-selectin was found to be unrelated to serum LDL-c when receiving DAPT with ticagrelor (p > 0.4) or clopidogrel (p > 0.8). In conclusion, our preliminary observational study suggests the association of lower residual ex vivo platelet aggregability with better LDL-c control in patients undergoing ticagrelor-based maintenance DAPT, which does not appear to be reflected by plasma sP-selectin. Whether the serum LDL-c level should be considered among the factors affecting the degree of platelet inhibition for those treated with ticagrelor-based DAPT needs to be investigated in larger studies.

The Role of Platelets in Diabetic Kidney Disease

Diabetic kidney disease (DKD) is among the most common microvascular complications in patients with diabetes, and it currently accounts for the majority of end-stage kidney disease cases worldwide. The pathogenesis of DKD is complex and multifactorial, including systemic and intra-renal inflammatory and coagulation processes. Activated platelets play a pivotal role in inflammation, coagulation, and fibrosis. Mounting evidence shows that platelets play a role in the pathogenesis and progression of DKD. The potentially beneficial effects of antiplatelet agents in preventing progression of DKD has been studied in animal models and clinical trials. This review summarizes the current knowledge on the role of platelets in DKD, including the potential therapeutic effects of antiplatelet therapies.

Low hemoglobin predicts high-platelet reactivity and major cardiovascular ischemic events at long-term follow-up among ACS patients receiving dual antiplatelet therapy with ticagrelor

BACKGROUND

Reduced levels of hemoglobin (Hb) represent an established marker of impaired outcomes and increased cardiovascular risk in patients with coronary artery disease, challenging the management of dual antiplatelet therapy (DAPT). However, while anemia has emerged as an independent predictor of suboptimal platelet inhibition in patients receiving clopidogrel, no study has so far evaluated the impact of Hb levels on high-on treatment platelet reactivity (HRPR) with ticagrelor and their prognostic consequences, that were the aim of the present study.

METHODS

Patients on DAPT with ASA + Ticagrelor (90 mg/twice a day) after percutaneous coronary revascularization for ACS were scheduled for platelet function assessment 30-90 days post-discharge. Aggregation tests were performed by multiple electrode aggregometry. Suboptimal platelet inhibition (HRPR-high residual platelet reactivity was defined if above the lower limit of normality (417 AU*min). The primary study endpoint was defined as the occurrence of major cardiovascular events (a composite of cardiovascular death, recurrent acute coronary syndrome [MI], target vessel revascularization) at longest available follow-up.

RESULTS

We included 397 patients that were divided according to tertiles values of Hb (< 12.7, 12-7-14.09, ≥14.1 g/dl). Patients with lower Hb were older and displayed a more severe cardiovascular risk profile. Mean levels of platelet reactivity were enhanced in patients with lower Hb after stimulation with TRAP peptide (TRAP test, p = .03) and ADP (p = .02). Elevated platelet reactivity (HRPR) on Ticagrelor was more frequent among patients with reduced Hb (16.4% vs. 12% vs. 5.4%, p = .005, adjusted OR [95%CI] = 1.71[0.996;3.01], p = .056). At a mean follow-up of 820.9 ± 553.4 days, 21.4% of the patients experienced the primary composite endpoint, with a higher rate of events in patients with lower Hb (27.6% vs. 22.6% vs. 13.5%, p = .006, adjusted HR [95%CI] = 1.51[1.12; 2.03], p = .006), mainly driven by a higher rate of recurrent ACS. After correction for baseline differences lower Hb tertiles but not HRPR emerged as independent predictor of MACE (adjusted HR [95%CI] = 0.98[0.50; 1.92], p = .95).

CONCLUSIONS

In the present study, we demonstrated that among patients on DAPT with ASA and ticagrelor after PCI for ACS, lower Hb levels are independently associated with a higher rate of HRPR and an increased rate of major ischemic events, and especially for recurrent ACS, although with no impact on survival. Neutral prognostic effect of HRPR was observed across Hb tertiles.

Ticagrelor and prasugrel in acute coronary syndrome: a single-arm crossover platelet reactivity study

AIM

To compare the degree of platelet inhibition between ticagrelor and prasugrel in patients undergoing percutaneous coronary intervention for acute coronary syndrome.

METHODS

Platelet function was assessed by impedance aggregometry after 30-90 days of therapy with acetylsalicylic acid and ticagrelor and over 15 days after switching to prasugrel. High-on-treatment platelet reactivity (HRPR) was defined for ADP test results above the upper limit of normal.

RESULTS

A total of 105 patients were included, 81.9% males and 33.3% people with diabetes, with a mean age of 60.8 ± 8.1 years. Mean platelet reactivity was not significantly different between the two antiplatelet strategies, as the prevalence of HRPR (8.6 vs 12.3%, P = 0.50). Switching between the two antiplatelet agents was safe and well tolerated, and effectively reduced platelet reactivity in over 95% of the patients (only 3.8% of the study population displaying ineffective response to both drugs).

CONCLUSION

Ticagrelor and prasugrel have a similar effect on platelet reactivity. Switching between the two drugs can be safely done.

Impact of gender on immature platelet count and its relationship with coronary artery disease

The impact of platelet parameters on the cardiovascular risk is still debated. Gender differences in platelet volume indexes and turnover have been previously reported, potentially conditioning their role in the development of coronary artery disease (CAD). However, few studies have addressed, so far, the impact of gender on the immature platelet fraction (IPF) and count (IPC) and their relationship with CAD. We enrolled consecutive patients undergoing coronary angiography in a single centre. IPF and platelet indexes were measured at admission. Significant CAD was defined as the presence of at least one coronary stenosis more than 50%. A total of 2550 patients were included, 1835 (72%) were males, and 715 (28%) were females. Female patients were older (p < 0.001), with lower BMI (p = 0.002), lower prevalence of active smoking (p < 0.001), previous MI, previous PCI and CABG (p = 0.001, p = 0.001, p < 0.001), whilst a higher prevalence of renal failure (p = 0.02), acute presentation (p < 0.001) and CAD (p < 0.001). Platelet count was higher in females (p < 0.001), as well as the IPC levels (838.38 ± 562.05 vs 792.24 ± 535.66, p = 0.05) with no difference in the levels of immature platelet fraction (3.67 ± 2.68% vs 3.74 ± 2.6%, p = 0.55) or the prevalence of patients with IPF ≥ 3rd tertile (33.7% vs 35.2%, p = 0.26). At multivariate analysis, after correction for baseline confounders, gender did not emerge as an independent predictor of higher IPF (adjusted OR [95% CI] = 0.82 [0.64-1.06], p = 0.13). When dividing our patients according to the levels of IPF, in women we observed an inverse association between IPF ≥ 3rd tertile and coronary calcifications (p = 0.025) and a higher prevalence of restenosis (p = 0.003), but no difference in CAD (65.6% vs 66.9%, p = 0.71) or severe CAD (28.1% vs 24.7%, p = 0.31). In males, the IPF ≥ 3rd tertile related with a lower TIMI flow (p = 0.001). Males with lower IPF had a significantly higher percentage of CAD (87.7% vs 83.3%, p = 0.007; adjusted OR: 0.699 [95% CI] = [0.54-0.91], p = 0.008) but not for severe CAD (36.5% vs 39.9%, p = 0.134). The present study shows that among patients undergoing coronary angiography, gender is not associated to the levels of immature platelet fraction. Moreover, we found no association between IPF and the prevalence and extent of CAD in female gender, whereas in male gender the IPF was inversely related with the prevalence of CAD.

Higher neutrophil-to-lymphocyte ratio (NLR) increases the risk of suboptimal platelet inhibition and major cardiovascular ischemic events among ACS patients receiving dual antiplatelet therapy with ticagrelor

BACKGROUND

Neutrophil to lymphocyte ratio (NLR) has emerged as a useful and easy-to-assess prognostic tool and biomarker of cardiovascular risk. However, few studies have evaluated its role on platelet inhibition among patients on dual antiplatelet therapy (DAPT), and especially in the settings of acute coronary syndromes (ACS). We aimed at assessing the impact of NLR on platelet reactivity and the risk of major ischemic events at long-term follow-up among ACS patients on DAPT with ticagrelor.

METHODS

Patients on dual antiplatelet therapy with ASA + ticagrelor (90 mg/twice a day) after percutaneous coronary revascularization for ACS were scheduled for platelet function assessment 30-90 days post-discharge. Aggregation tests were performed by Multiple Electrode Aggregometry (MEA). Suboptimal platelet inhibition (HRPR-high residual platelet reactivity was defined if above the lower limit of normality (417 AU*min). The primary study endpoint was defined as the occurrence of major cardiovascular events (a composite of cardiovascular death, recurrent acute coronary syndrome, target vessel revascularization) at longest available follow-up.

RESULTS

We included 397 patients, that were divided according to NLR tertiles. Patients with higher NLR were older (p < .001), less frequently smokers (p = .03), with higher rates of renal failure (p = .001), previous bypass surgery (p = .05) and use of statins (p = .03) and diuretics (p = .01). Higher white blood cells count and C-reactive protein (p < .001) and lower haemoglobin (p = .001) were associated with NLR. Mean platelet reactivity and the prevalence of high platelet reactivity (HRPR) on ticagrelor were significantly associated to higher NLR tertiles values (7% vs 12% vs 14.3%, p = .04), with a significant relationship between NLR and platelet reactivity being confirmed for all the different activating stimuli. At a mean follow-up of 939 ± 581.4 days, 21.2% of the patients experienced the primary composite endpoint, with a trend for a higher risk of events across NLR tertiles (15.4% vs 24.2% vs 24.4%, p = .09), that became statistically significant after correction for baseline confounders (adjusted HR[95%CI] = 1.13[1.008-1.26], p = .036). Moreover, NLR was significantly associated to overall mortality and recurrent ACS (adjusted p = .008, p = .06 and p = .02 respectively).

CONCLUSIONS

In the present study we found that among ACS patients treated with ASA and ticagrelor after PCI, suboptimal platelet inhibition despite DAPT was significantly increased for higher values of Neutrophil-to-Lymphocyte Ratio. Moreover, mortality and the risk of recurrent major ischemic events at long-term were associated to NLR.

Impact of diabetes on clinical outcome among elderly patients with acute coronary syndrome treated with percutaneous coronary intervention: insights from the ELDERLY ACS 2 trial

BACKGROUND

Despite recent improvements in percutaneous coronary revascularization and antithrombotic therapies for the treatment of acute coronary syndromes, the outcome is still unsatisfactory in high-risk patients, such as the elderly and patients with diabetes. The aim of the current study was to investigate the prognostic impact of diabetes on clinical outcome among patients included in the Elderly-ACS 2 trial, a randomized, open-label, blinded endpoint study carried out at 32 centers in Italy.

METHODS

Our population is represented by 1443 patients included in the Elderly-ACS 2 trial. Diabetes was defined as known history of diabetes at admission. The primary endpoint of this analysis was cardiovascular mortality, while secondary endpoints were all-cause death, recurrent myocardial infarction, Bleeding Academic Research Consortium type 2 or 3 bleeding, and rehospitalization for cardiovascular event or stent thrombosis within 12 months after index admission.

RESULTS

Diabetes was present in 419 (29%) out of 1443 patients. Diabetic status was significantly associated with major cardiovascular risk factors and history of previous coronary disease, presentation with non-ST segment elevation myocardial infarction (P = 0.01) more extensive coronary disease (P = 0.02), more advanced Killip class at presentation (P = 0.003), use at admission of statins (P = 0.004) and diuretics at discharge (P < 0.001). Median follow-up was 367 days (interquartile range: 337-378 days). Diabetic status was associated with an absolute increase in the rate of cardiovascular mortality as compared with patients without diabetes [5.5 vs. 3.3%, hazard ratio (HR) 1.7 (0.99-2.8), P = 0.054], particularly among those treated with clopidogrel [HR (95% confidence interval (CI)) = 1.89 (0.93-3.87), P = 0.08]. However, this difference disappeared after correction for baseline differences [Adjusted HR (95% CI) 1.1(0.4-2.9), P = 0.86]. Similar findings were observed for other secondary endpoints, except for bleeding complications, significantly more frequent in diabetic patients [HR (95% CI) 2.02 (1.14-3.6), P = 0.02; adjusted HR (95% CI) = 2.1 (1.01-4.3), P = 0.05]. No significant interaction was observed between type of dual antiplatelet therapy, diabetic status and outcome.

CONCLUSION

Among elderly patients with acute coronary syndromes, diabetic status was associated with higher rates of comorbidities, more severe cardiovascular risk profile and major bleeding complications fully accounting for the absolute increase in mortality. In fact, diabetes mellitus did not emerge as an independent predictor of survival in advanced age.

Impact of diabetes mellitus on immature platelet fraction and its association with coronary artery disease

BACKGROUND

Higher prothrombotic status and alterations in platelet function and thrombopoiesis are associated with diabetes mellitus (DM). We assessed the impact of diabetes and glucose control on the immature platelet fraction (IPF) and their relationship with prevalence and extent of coronary artery disease (CAD).

METHODS

Consecutive patients undergoing coronary angiography were included. Significant CAD was defined as at least one vessel stenosis greater than 50%. IPF levels were measured at admission by routine blood cells count (A Sysmex XE-2100).

RESULTS

We included 1781 patients, of whom 660 (37.1%) suffered from diabetes. Diabetes was associated with advanced age and a higher cardiovascular risk profile. No difference in the mean values of IPF were observed between patients with or without DM (3.6 ± 2.5 vs 3.5 ± 2.5, P = 0.39) and neither in the rate of patients with IPF above the median (2.9%) (51.6% vs 50.6%, P = 0.73). In patients with DM, the IPF levels did not relate with glucose control parameters (glycaemia: r = -0.024, P = 0.54, glycosylated haemoglobin: r = 0.11, P = 0.72). The prevalence of CAD was significantly lower in patients with DM and IPF greater than the median (80.5% vs 86.5%, P = 0.04, adjusted odds ratio [OR] [95% confidence interval {CI}] = 0.57[0.36-0.91], P = 0.02), while not left main/three-vessel CAD (36.9% vs 38.2%, P = 0.75, adjusted OR [95%CI] = 0.91[0.64-1.28], P = 0.90).

CONCLUSION

In the present study, neither DM nor glucose control are independent predictors of IPF above the median. In patients with DM, higher IPF levels were associated with a lower prevalence of CAD and with a similar extent of severe CAD and angiographic findings. Therefore, until new data become available, elevated IPF should not be systematically applied on a large scale as cardiovascular risk marker in patients with diabetes.

Gender Differences in Platelet Reactivity in Diabetic Patients Receiving Dual Antiplatelet Therapy

BACKGROUND

Increased comorbidities and a perceived high-bleeding risk often prevent the use of dual antiplatelet therapy (DAPT) in female patients. However, more aggressive antiplatelet treatment would certainly offer additional outcome benefits in coronary artery disease, especially among diabetic patients. The aim of the present study was to evaluate the gender differences in high-residual on treatment platelet reactivity (HRPR) among diabetic patients treated with DAPT.

METHODS

Our population is represented by a consecutive cohort of diabetic patients treated with DAPT (ASA + clopidogrel, ticagrelor or dose-adjusted prasugrel) for an acute coronary syndrome or elective PCI, undergoing platelet reactivity assessment at 30-90 days post-discharge. Aggregation was assessed by multiple-electrode aggregometry and in diabetic patients naïve to antiplatelet therapy, by light transmission aggregometry, surface expression of P-selectin and plasma concentration of Thromboxane B2.

RESULTS

We included 472 patients, 113 (23.9%) women. Female gender was associated with more advanced age, and increased comorbidities. Mean platelet reactivity did not differ according to gender. The rate of HRPR was similar in women as compared to men (for ASA: adjusted OR[95%CI] = 0.59[0.27-1.33], p = 0.21, for ADP-antagonists: adjusted OR[95%CI] = 1.24[0.25-1.80], p = 0.27), however, the benefits of the new ADP-antagonists on platelet reactivity were lower in women than in men (p interaction = 0.01). No impact of gender on platelet reactivity was confirmed among 50 diabetic patients naïve to antiplatelet therapy.

CONCLUSIONS

Among diabetic patients receiving dual antiplatelet therapy gender does not affect platelet reactivity or high-on treatment platelet reactivity. However, the enhanced platelet inhibition provided by the new-ADP antagonists of new-ADP antagonists could be mitigated in women.

Factors associated with platelet reactivity during dual antiplatelet therapy in patients with diabetes after acute coronary syndrome

Antiplatelet drugs are prescribed without considering the diabetic status of the patient. The objective of the current investigation was to determine the impact of clinical factors, CYP4F2 enzyme and 20-hydroxyeicosatetraenoic acid (20-HETE) concentrations on high on-treatment platelet reactivity in patients with diabetes treated with antiplatelet drugs following acute coronary syndromes. A total of 667 patients were included in the study. Dual antiplatelet drug loading dosages with aspirin (300 mg) and ticagrelor (180 mg) or clopidogrel (600 mg) were prescribed to all the studied patients. Testing of platelet aggregation was performed the day after loading antiplatelet drug dosages. Platelet aggregation test was done according to the classical Born method. Multivariate binary regression analysis demonstrated that insulin use and higher 20-HETE concentration increased the odds of high on-treatment platelet reactivity during the initiation of antiplatelet drug therapy (OR: 3.968, 95% CI: 1.478-10.656, p = 0.006 and OR: 1.139, 95% CI: 1.073-1.210, respectively, p < 0.001). Ticagrelor use decreased the odds of developing high on-treatment platelet reactivity (OR: 0.238, 95% CI: 0.097-0.585, p = 0.002). Data from this study revealed that high on-treatment platelet reactivity during dual antiplatelet therapy in patients with diabetes may depend on such factors as insulin prescription and 20-HETE concentration.

Impact of aging on platelet reactivity in diabetic patients receiving dual antiplatelet therapy

Advanced age and diabetes represent summative conditions in the determination of cardiovascular risk, and especially for the management of dual antiplatelet therapy (DAPT), often requiring balancing between bleeding and thrombotic complications. However, few studies have so far evaluated the impact of age on platelet reactivity and suboptimal platelet inhibition (high-on treatment platelet reactivity-HRPR) on DAPT among diabetic patients, that was, therefore the aim of the present study. In diabetic patients treated with DAPT (ASA + clopidogrel or ticagrelor) platelet reactivity was assessed at 30-90 days post-discharge for an acute coronary syndrome or elective PCI. Aggregation was assessed by multiple-electrode aggregometry. HRPR was defined for values above the lower limit of normality (in non-treated patients). Elderly patients were considered ≥ 75 years of age. We included 462 patients, among them 149 (32.2%) were ≥ 75 years. Elderly patients were more often females (p = 0.006), with lower body size (p = 0.04), acute coronary syndrome at presentation and renal failure (p < 0.001), non-smokers (p = 0.002), in therapy with insulin (p = 0.02) and diuretics (p < 0.001) and lower rate of betablockers (p = 0.02). Age directly related with C reactive protein (p = 0.01), creatinine levels and inversely with hemoglobin (p < 0.001) and triglycerides (p = 0.003). No association was found at linear regression analysis for platelet reactivity and age with different activating stimuli, but for ASPI test (r = 0.12; p = 0.03). No significant difference in HAPR was found in elderly patients (2.4 vs. 3.2%, p = 0.76, OR[95% CI] = 0.45[0.1-2.11], p = 0.31). HRPR for ADP antagonists was similarly not affected by age (30.1% vs. 35.7%, p = 0.28, adjusted OR[95% CI] = 0.78[0.47-1.29], p = 0.33). Comparable results were obtained when considering separately the DAPT strategies with clopidogrel or ticagrelor, or when adjusting our results according to propensity score values. Among diabetic patients receiving dual antiplatelet therapy for an acute coronary syndrome or elective percutaneous coronary intervention, age does not affect platelet reactivity or the rate of high-on treatment platelet reactivity. Similar results were obtained for ASA and clopidogrel or ticagrelor.

Vitamin D levels and platelet reactivity in diabetic patients receiving dual antiplatelet therapy

BACKGROUND

Hypovitaminosis D represents an emerging cardiovascular risk factor, and especially among higher-risk subsets of patients, such as in those with diabetes mellitus. The anti-inflammatory and anti-thrombotic properties of vitamin D, in fact, could be even more beneficial among diabetics, where platelet hyperreactivity and suboptimal response to antiplatelet drugs has been associated with poorer outcomes. However, no study has so far evaluated the impact of vitamin D levels on platelet reactivity and high-on treatment platelet reactivity (HRPR) among diabetic patients receiving dial antiplatelet therapy (DAPT).

METHODS

Our population is represented by a consecutive cohort ofdiabetic patients treated with DAPT (ASA + clopidogrel or ticagrelor or dose-adjusted prasugrel) for an acute coronary syndrome or elective PCI, undergoing platelet reactivity assessment at 30-90 days post-discharge. Aggregation was assessed by multiple-electrode aggregometry. HRPR was defined for values above the lower limit of normality (in non-treated patients).

RESULTS

We included 440 patients, that were divided according to quartiles values of vitamin D (< 9.4; 9.4-15.59; 15.6-21.64; ≥ 21.65 ng/ml). Among them, 31 were excluded as chronically treated with vitamin D supplementation. Lower vitamin D quartiles were associated with more advanced age (p = 0.01), female gender (p = 0.04), renal failure (p = 0.005), history of previous MI (p = 0.01), CABG and use of diuretics (p = 0.003), severe coronary disease (p = 0.002), but lower ejection fraction (p = 0.001), treatment with statins (p = 0.04) and new ADP-antagonists (p = 0.002). Vitamin D levels related with higher HbA1c (p = 0.001), cholesterol (p = 0.02) and creatinine (p = 0.004) and lower hemoglobin (p = 0.004). The prevalence of HRPR with ASA was low and not related to vitamin D quartiles (3.4% vs 2.7% vs 1.8% vs 2.1%, p = 0.44; adjusted OR[95%CI] = 1.16[0.60-2.26], p = 0.67). The prevalence of HRPR for ADP antagonists was associated to hypovitaminosis D (40.2% vs 29.1% vs 29.4% vs 25.5%, p = 0.03; (adjusted OR[95%CI] = 1.76[1.04-2.98], p = 0.036for I vs II-IV quartile). The impact of vitamin D quartiles, was significant only in patients on new ADP antagonists (n = 225, of whom 81 on prasugrel 5 mg; p = 0.03; adjusted OR[95%CI] = 3.12[1.34-7.49], p = 0.009) but not with clopidogrel (p = 0.85, adjusted OR[95%CI] = 1.05[0.49-2.24], p = 0.89).

CONCLUSIONS

Among diabetic patients receiving dual antiplatelet therapy for an acute coronary syndrome or elective percutaneous coronary intervention, severe vitamin D deficiency is associated with a higher ADP-mediated platelet reactivity and rate of HRPR, and especially for new ADP-antagonists over clopidogrel.

Use of Metformin and Platelet Reactivity in Diabetic Patients Treated with Dual Antiplatelet Therapy

BACKGROUND

Enhanced platelet reactivity represents one of the major determinants of cardiovascular risk among diabetic patients. The aim of the present study was to evaluate the impact of metformin use on platelet reactivity in diabetic patients receiving dual antiplatelet therapy (DAPT).

METHODS

We included diabetic patients treated with DAPT after an acute coronary syndrome or percutaneous coronary intervention. Platelet reactivity was assessed at 30-90 days by Multiple-electrode aggregometry. In an additional cohort of diabetic patients naïve to antiplatelet therapy, we assessed platelet reactivity by light transmission aggregometry, surface expression of P-selectin and plasma concentration of Thromboxane B2 (TxB2).

RESULTS

We included 219 diabetic patients, 117 (53.4%) treated with metformin. Metformin was associated with younger age (p=0.03), male gender (p=0.02), lower rate of hypertension (p=0.04), active smoker (p=0.002), previous MI (p<0.001) renal failure (p<0.001), fibrinogen (p<0.001) and C-reactive protein (p=0.04), larger use of diuretics (p=0.04) calcium antagonists (p=0.05), better glycemic control (p<0.001) and higher haemoglobin (p=0.003). The prevalence of HAPR did not significantly differ according to hypoglycemic treatment (p=0.73; adjusted OR[95%CI]=5.63[0.42-76], p=0.19). Moreover, no impact of metformin was observed for HRPR (p=0.77; adjusted OR[95%CI]=1.15[0.55-2.4], p=0.71). Among an additional cohort of 42 diabetic patients naïve to antiplatelet therapy, we confirmed no impact of metformin or insulin on aggregation.

CONCLUSIONS

Our study found no apparent association in diabetic patients treated with DAPT, between the use of metformin and platelet reactivity or the rate of HPR.

Consistent platelet inhibition with ticagrelor 60 mg twice-daily following myocardial infarction regardless of diabetes status

Diabetes increases cardiovascular risk and reduces pharmacodynamic response to some oral antiplatelet drugs. This study aimed to determine whether ticagrelor 60 mg twice daily (bid) provided potent and consistent platelet inhibition in patients with vs without diabetes in the PEGASUS-TIMI 54 platelet function substudy. Out of 180 patients studied, 58 patients were randomised to and had received at least four weeks of ticagrelor 60 mg bid, with 20 (34 %) having diabetes, 58 patients received ticagrelor 90 mg bid, with 12 (21 %) having diabetes, and 64 patients received placebo, with 18 (28 %) having diabetes. Blood was sampled pre- and 2 hours post-maintenance dose. In patients treated with ticagrelor 60 mg bid, on-treatment platelet reactivity to ADP, as determined by light transmission aggregometry (LTA), VerifyNow and VASP, was similar in patients with vs without diabetes (LTA post-dose, ADP 20 µM: 29 ± 14 vs 34 ± 10 %, respectively; p = 0.19). A consistent inhibitory effect of ticagrelor 60 mg bid was observed pre- and post-dose regardless of diabetes status, even in insulin-treated patients. Patients with diabetes did not have an increased incidence of high platelet reactivity in either ticagrelor group. Platelet reactivity was similar in patients with diabetes treated with ticagrelor 60 mg vs 90 mg bid. Pharmacokinetics of ticagrelor were not affected by diabetes status. In conclusion, ticagrelor 60 mg bid is equally effective at reducing platelet reactivity in patients with and without diabetes, yielding a consistently high level of platelet inhibition regardless of diabetes status.

Impact of Glycemic Control on Efficacy of Clopidogrel in Transient Ischemic Attack or Minor Stroke Patients With CYP2C19 Genetic Variants

BACKGROUND AND PURPOSE

Dysglycemia may influence the predictive value of CYP2C19 loss-of-function allele for clinical efficacy of antiplatelet drug, but the role of glycated albumin (GA) remains unclear in patients with stroke on antiplatelet drugs.

METHODS

The CHANCE trial (Clopidogrel in High-Risk Patients With Acute Nondisabling Cerebrovascular Events) included 2933 patients who had GA levels and CYP2C19 genotyping. Cox proportional hazards model was used to assess the interaction between CYP2C19 loss-of-function allele (*2, *3) carrier status and the effect of antiplatelet therapy based on their GA levels.

RESULTS

There was significant interaction between carrier status and antiplatelet therapy regimen on the risk of recurrent stroke (P=0.03) in patients with GA levels of ≤15.5%, but not in those with GA levels of >15.5% (P=0.48). Only in noncarriers with low GA levels, dual-antiplatelet therapy reduced stroke recurrence (3.5%) compared with those on aspirin alone (14.7%; hazard ratio, 0.23; 95% confidence interval, 0.10-0.49; P<0.001). Similar effects were observed when examined the combined vascular event or ischemic stroke. No significant difference in bleeding was found among groups.

CONCLUSIONS

In patients with minor stroke or high-risk transient ischemic attack, clopidogrel-aspirin when compared with aspirin alone reduced stroke recurrence only in noncarriers of CYP2C19 loss-of-function allele and normal GA levels.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00979589.

Platelet aggregation and risk of stent thrombosis or bleeding in interventionally treated diabetic patients with acute coronary syndrome

Background

Platelet aggregation monitoring in diabetic patients treated with coronary interventions (PCI) for an acute coronary syndrome (ACS) is a promising way of optimizing treatment and outcomes in this high risk group. The aim of the study was to verify whether clopidogrel response measured by Multiplate analyzer (ADPtest) in diabetic ACS patients treated with PCI predicts the risk of stent thrombosis or cardiovascular mortality and bleeding.

Methods

Into this prospective, observational study 206 elective PCI patients were enrolled. Two cutoff points of ADPtest were used in analysis to divide patients into groups. One (345 AU x min) was calculated based on ROC curve analysis; this cutoff provided the best ROC curve fit, although it did not reach statistical significance. The other (468 AU x min) was accepted based on the consensus of the Working Group on On-Treatment Platelet Reactivity. The risk of stent thrombosis and mortality was assessed using Cox regression analysis and Kaplan-Meier curves.

Results

The risk of stent thrombosis was higher in the group of patients with impaired clopidogrel response for either cutoff value (for >354 AU x min - HR 12.33; 95% CI 2.49–61.1; P = 0.002). Cardiovascular mortality was also higher in the impaired clopidogrel response group (for >354 AU x min - HR 10.58; 95% CI 2.05–54.58; P = 0.005). We did not find a clear relation of increased clopidogrel response to the risk of bleeding.

Conclusions

The results of this study show that in diabetic ACS patient group treated with PCI an impaired platelet response to clopidogrel measured by the Multiplate analyzer results in increased risk of stent thrombosis and cardiac death.