Matteo Nardin

Prevalence and predictors of high-on treatment platelet reactivity with ticagrelor in ACS patients undergoing stent implantation.

BACKGROUND Residual high-on treatment platelet reactivity (HRPR) predicts outcomes and major cardiovascular events. Ticagrelor has provided pharmacological and clinical evidence of more predictable and more potent antiplatelet effect as compared to clopidogrel. However, so far, few data have investigated the prevalence and predictors of HRPR in unselected patients treated with ticagrelor, that is therefore the aim of the current study. METHODS AND RESULTS Our population is represented by 195 patients undergoing coronary stenting for ACS and receiving ASA and ticagrelor. Platelet function was assessed by multiplate impedance aggregometry (MEA) between 1 and 3months after stenting. Main clinical features and biochemistry parameters were collected. HRPR for ticagrelor was defined for aggregation>417 AUC after MEA-ADP stimulation. A total of 26 patients, (13.3%), displayed HRPR with ticagrelor. Older age (≥70years, p=0.002), hypertension (p=0.02) previous myocardial infarction (p=0.04), therapy with nitrates and beta-blockers (p=0.02), diuretics (p=0.03) and fasting glycaemia (p=0.05) were associated to HRPR with ticagrelor. By multivariate analysis, age≥70years (OR [95%CI]=4.6[1.55-13.8], p=0.006), concomitant therapy with beta-blockers (OR [95%CI]=3.2[1.06-9.6], p=0.04) and platelets count (OR[95%CI]=1.0007 [1-1.016], p=0.05) were identified as independent predictors of HRPR with ticagrelor. CONCLUSION The present study firstly demonstrates that the occurrence of HRPR in patients treated with ticagrelor is not so futile, as it was observed in 13% of patients treated with ticagrelor. Older age, beta-blockers administration and platelets count are independent predictors of HRPR with ticagrelor.

Dual Versus Single Antiplatelet Regimen With or Without Anticoagulation in Transcatheter Aortic Valve Replacement: Indirect Comparison and Meta-analysis

INTRODUCTION AND OBJECTIVES There is uncertainty on the correct management of antithrombotic therapies after transcatheter aortic valve replacement (TAVR), with dual antiplatelet therapy (DAPT) being currently recommended on an empirical basis. The aim of the present meta-analysis was to assess the safety and effectiveness of DAPT in patients undergoing TAVR. METHODS Studies comparing different antithrombotic regimens after TAVR were included. The primary endpoint was 30-day overall mortality. RESULTS We included 9 studies, 5 comparing DAPT with aspirin monotherapy and 4 comparing DAPT with monoantiplatelet therapy (MAPT) + oral anticoagulation. Among 7991 patients, 72% were on DAPT. The median follow-up was 3.5 months. Mortality was significantly lower in the DAPT group (12.2% vs 14.4%; OR, 0.81; 95%CI, 0.70-0.93; P = .003; Phet = .93), with similar benefits compared with aspirin monotherapy (OR, 0.80; 95%CI, 0.69-0.93; P = .004; Phet = .60), which were not statistically significant when compared with MAPT + oral anticoagulation (OR, 0.86; 95%CI, 0.55-1.35; P = .51; Phet = .97). A similar trend for DAPT was observed for stroke (OR, 0.83 95%CI, 0.63-1.10; P = .20; Phet = .67), with no increase in the rate of major bleedings (OR, 1.69; 95%CI, 0.86-3.31; P = .13; Phet< .0001). On indirect comparison analysis, no benefit in survival, stroke, or bleedings was identified for additional oral anticoagulation. CONCLUSIONS The present meta-analysis supports the use of DAPT after TAVR, reducing mortality and offering slight benefits in stroke, with no increase in major bleedings compared with MAPT. The strategy of aspirin + oral anticoagulation did not provide significant benefits compared with MAPT or DAPT.

Impact of diabetes on uric acid and its relationship with the extent of coronary artery disease and platelet aggregation: A single-centre cohort study

BACKGROUND Serum uric acid (SUA) elevation has been associated with the main determinants of atherosclerosis and metabolic syndrome, although an independent relationship between SUA and coronary artery disease (CAD) has never been confirmed. Recent reports suggested a central role of SUA in diabetic patients, possibly being an early marker of impaired glucose metabolism and best predicting the risk of cardiovascular events in these patients. Aim of current study was to evaluate the relationship between diabetes and uric acid and its association with the extent of CAD and platelet aggregation among diabetics. METHODS In diabetic patients undergoing coronary angiography, fasting samples were collected for uric acid levels assessment. Coronary disease was defined for at least 1 vessel stenosis>50% as evaluated by QCA. RESULTS Diabetes was observed in 1173 out of 3280 (35.7%) diabetes was related to age, hypercholesterolemia, hypertension, BMI, renal failure, previous MI or coronary revascularization (p<0.001, respectively) and smoking (p=0.001). Diabetics were more frequently treated with ACE-inhibitors, ARBs, b-blockers, calcium-antagonists, diuretics, statins (p<0.001, respectively), and ASA (p=0.004). Diabetics displayed higher glycemia and HbA1c (p<0.001), higher creatinine and triglycerides (p<0.001) but lower total and HDL cholesterol (p<0.001) and haemoglobin (p<0.001). No significant difference was found in SUA levels between diabetic and non diabetic patients (p=0.09). In fact, we identified age, renal failure, hypertension, smoking, BMI, use of diuretics, statins, haemoglobin, triglycerides and HDL cholesterol levels as independent predictors of higher levels of uric acid (3rd tertile,≥6.7mg/dl or 0.39mmol/l). Among diabetic patients, no relationship was found between uric acid and the extent of coronary artery disease (p=0.27; adjusted OR [95%CI]=0.93 [0.76-1.1], p=0.48), or severe (LM-trivessel) CAD (P=0.05; adjusted OR [95%CI]=1.01 [0.86-1.18], p=0.94). Furthermore, SUA levels did not influence platelet aggregation. CONCLUSION Ageing, BMI, renal failure, hypertension, smoking, use of statins and diuretics, haemoglobin, HDL cholesterol and tryglicerides levels but not diabetes or glycemic control are independent predictors of hyperuricemia. Among diabetic patients, higher SUA is not independently associated with the extent of CAD or with platelet aggregation.

Body Mass Index and Platelet Reactivity During Dual Antiplatelet Therapy With Clopidogrel or Ticagrelor

Introduction: Dual antiplatelet therapy (DAPT) is considered essential in clinical management of patients undergoing percutaneous coronary revascularization or acute coronary syndromes. However, the optimal platelet inhibition is not always obtained, with high residual platelet reactivity (HRPR) increasing stent thrombosis and recurrent ischemic events. Aim of this study was to investigate the impact of body mass index (BMI) on platelet reactivity in patients on DAPT. Methods: We included patients treated with acetylsalycilic acid (ASA) (100–160 mg) and clopidogrel (75 mg) or ticagrelor (90 mg twice a day) for acute coronary syndromes or drug-eluting stent implantation. Platelet reactivity was assessed at 30–90 days postdischarge by multiple-electrode aggregometry. HRPR for adenosine diphosphate (ADP) antagonists was defined as ADP test results >417 AU*min. HRPR for ASA was considered for ASPI test >862 AU*min. Results: Our population is represented by 498 patients, 308 (61.8%) were treated with clopidogrel and 190 (38.2%) with ticagrelor. Overall, higher BMI was related with younger age (P = 0.003), higher prevalence of diabetes mellitus (P < 0.001), hypercholesterolemia (P = 0.017), hypertension (P < 0.001), chronic therapy with angiotensin-receptor blockers (P = 0.019), calcium channel blockers (P = 0.003). Higher values of BMI directly related with hemoglobin (P = 0.02), triglycerides (P < 0.001), glycemia (P = 0.035), HbA1c (P < 0.001), and inversely related with high-density lipoprotein cholesterol (P = 0.01). BMI did not influence the effectiveness of ASA, whereas it was associated to a nonsignificant trend for higher platelet reactivity (r = 0.08, P = 0.08) for ADP antagonists. In fact, 111 patients (22.3%) displayed HRPR at ADP test (>417 AU*min) with no statistically significant difference according to BMI {20.3% vs. 27.1% vs. 25.7%, P = 0.28; adjusted odds ratio [OR] [95% confidence interval (CI)] = 1.19 [0.86–1.64], P = 0.30}. However, results were different when considering separately patients receiving clopidogrel or ticagrelor. In the clopidogrel-treated subgroup, significantly higher ADP-mediated aggregation values were found in patients with higher BMI (r = 0.14, P = 0.023) that emerged as an independent predictor of HRPR with clopidogrel [OR (95% CI), 1.45 (1.01–2.12), P = 0.049]. On the contrary, no impact of BMI was observed in the ticagrelor-treated subgroup for platelet reactivity (r = −0.036, P = 0.62) or the prevalence of HRPR [adjusted OR (95% CI), 0.73 (0.39–1.36), P = 0.32]. Conclusions: This study shows that among patients treated with DAPT for coronary artery disease, higher BMI is related to increased platelet reactivity and a higher prevalence of HRPR in clopidogrel-treated patients while not significantly influencing the effectiveness of ticagrelor or ASA.

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

Abstract Introduction Despite the recent advances, prognostic difference between diabetic and non diabetic patients is still marked after an acute coronary syndrome. Diabetes mellitus and poor glycemic control represent well established pro-thrombotic conditions, as inadequate glycemic control can lead to impaired responsiveness to antiplatelet therapies. Among new antiplatelet agents, ticagrelor has provided more potent platelet inhibition, potentially offering benefits in reducing residual high-on treatment platelet reactivity. However, no study has so far investigated the relationship between diabetes mellitus and platelet reactivity in patients treated with ticagrelor after an acute coronary syndrome (ACS). Methods In patients treated with acetylsalicylic acid (100–160mg) and ticagrelor (90mg twice a day) platelet reactivity was assessed at 30–90days post-discharge for an ACS. Diabetic status was defined before discharge. Multiple-electrode aggregometry was used to assess platelet function. High residual platelet reactivity was defined as ADP-test results >417AU∗min. Results Diabetes was observed in 86 out of 224 patients (38.4%). Diabetes was significantly associated with older age, higher BMI, renal failure, hypertension, treatment with diuretics, higher levels of WBC, glycaemia, HbA1c, and lower levels of HDL-cholesterol. Platelet reactivity was higher in diabetic patients as compared to non-diabetic ones for all the different activating stimuli tested. A total of 29 patients (12.9%) displayed high-residual platelet reactivity with ticagrelor with an almost double rate in diabetics as compared to non-diabetics (18.8% vs 9.4%, p =0.06; adjusted OR[95%CI]=2.12[1.1–4.1], p =0.025). A progressive increase of platelet reactivity was observed for higher HbA1c levels ( r =0.15, p =0.029). Conclusion The present study shows that diabetic patients display higher platelet reactivity despite dual antiplatelet therapy. In fact, diabetes mellitus emerged as independent predictor of high-residual platelet reactivity in post-ACS patients treated with ticagrelor.

Mean platelet volume and high-residual platelet reactivity in patients receiving dual antiplatelet therapy with clopidogrel or ticagrelor

Objective: High on-treatment platelet reactivity (HRPR) is associated with a two- to ninefold increased risk of recurrent ischemic events among patients receiving dual antiplatelet therapy (DAPT) for coronary artery disease. However, its determinants are still poorly understood. The aim of the present study was to assess the impact of mean platelet volume (MPV) on platelet reactivity in patients receiving DAPT after an acute coronary syndrome or PCI. Methods: Patients treated with DAPT (acetylsalicylic acid [ASA] and clopidogrel or ticagrelor) were scheduled for platelet function assessment at 30 – 90 days post-discharge. By whole blood impedance aggregometry, HRPR was considered for ASPI test > 862 aggregation units (AU)*min (for ASA) and ADP test values ≥ 417 AU*min (for ADP-antagonists). Results: Our population is represented by a total of 487 patients on DAPT, divided according to MPV tertiles (< 10.4 fl; 10.4 – 11.29 fl; ≥ 11.3 fl). Larger-sized platelets were associated with use of statins (p < 0.001) and beta-blockers (p = 0.03), higher hemoglobin levels (p = 0.002) and lower platelets count (p < 0.001). Higher platelet reactivity was observed at ASPI test in patients with higher MPV (r = 0.12, p = 0.008), but not for ADP-mediated aggregation (r = -0.007, p = 0.88). However, a low prevalence of HRPR was observed with ASA, with no impact of MPV tertiles (1.2 vs 1.1 vs 1.6%, p = 0.70, adjusted OR [95% CI] = 1.05 [0.51 – 1.77], p = 0.87). MPV did not influence the prevalence of HRPR for ADP-antagonists (25.9 vs 1 vs 26.5%, p = 0.89; adjusted OR [95% CI] = 1.1 [0.84 – 1.45], p = 0.50) with similar results among the 259 patients receiving clopidogrel (adjusted OR [95% CI] = 1.15 [0.82 – 1.62], p = 0.43) and the 228 patients on ticagrelor (adjusted OR [95% CI] = 1.46 [0.84 – 2.55], p = 0.18). Conclusion: In patients receiving DAPT, MPV does not affect the response to major antiplatelet therapies. In fact, MPV elevation does not influence the risk of HRPR with clopidogrel, ticagrelor or ASA.

Platelet reactivity in patients with impaired renal function receiving dual antiplatelet therapy with clopidogrel or ticagrelor.

BACKGROUND Suboptimal platelet inhibition still represents an important challenge, especially for patients undergoing percutaneous coronary interventions (PCI). Chronic kidney disease (CKD) is a common comorbidity of patients with coronary artery disease, and may potentially influence platelet reactivity. So far only few studies have assessed the role of CKD on response to dual antiplatelet therapy (DAPT) with conflicting results. Therefore, the aim of our study was to evaluate the impact of CKD on platelet function in patients treated with DAPT after a recent acute coronary syndrome (ACS) or PCI. METHODS Patients treated with DAPT, acetylsalicylic acid (ASA)+adenosine diphosphate antagonist (ADP-antagonist) such as clopidogrel or ticagrelor, for ACS or elective patients undergoing PCI were scheduled for platelet function assessment at 30-90 days post-discharge. Platelet function was assessed by whole blood impedance aggregometry (Multiplate®- Roche Diagnostics AG), high residual platelet reactivity (HRPR) was considered for ASPI test >862 AU*min (for ASA) and ADP test values ≥ 417 AU*min (for ADP-antagonists). Chronic renal failure was defined as an estimated glomerular filtration rate of 60 mol/min/1.73 m(2) or less, calculated by applying MDRD (Modification of Diet in renal Disease) formula. RESULTS Our population included a total of 537 patients of which 308 (57.3%) received ASA and clopidogrel and 229 (42.6%) received ASA and ticagrelor. Patients with renal failure at baseline (101 out of 537, 18.8%) were older, with higher prevalence of hypertension, previous myocardial infarction and coronary artery bypass graft surgery. Moreover, they had a lower ejection fraction at baseline and were more often in therapy with diuretics, but less often with statins at admission. They had lower haemoglobin and higher glycated haemoglobin. HRPR was observed in 1.5% of patients treated with ASA with no difference according to renal function (p=0.18). HRPR for ADP-antagonists was observed in 23.7% of patients, with no difference according to renal function (p=0.50). This result was confirmed either with clopidogrel (31.9% versus 38%, p=0.41) and ticagrelor (13.1% versus 10.8%, p=0.99), also after correction for all baseline confounders (clopidogrel: adjusted OR[95%CI]=1.26 [0.60-2.63], p=0.54) (ticagrelor: adjusted OR[95%CI]=0.95 [0.54-1.65], p=0.84). The absence of association between renal function and platelet reactivity was confirmed at linear regression analysis both with clopidogrel (r=-0.04, p=0.52) and ticagrelor (r=0.006, p=0.92). CONCLUSION In patients receiving DAPT, chronic renal failure did not influence ADP-mediated platelet reactivity, with both ticagrelor or clopidogrel. No influence of chronic renal failure was found on the effectiveness of ASA.

Vitamin D levels and high-residual platelet reactivity in patients receiving dual antiplatelet therapy with clopidogrel or ticagrelor

Abstract Background: Suboptimal platelet inhibition still represents an important challenge, especially for patients undergoing percutaneous coronary interventions (PCIs). However, very few are known so far on the predictors of high-residual platelet reactivity (HRPR) despite antiplatelet strategies. Increasing attention has been paid in the last years to the role of vitamin D in atherothrombosis. Therefore, the aim of our study was to evaluate the impact of vitamin D levels on platelet function in patients treated with dual antiplatelet therapy (DAPT). Patients treated with DAPT (ASA and clopidogrel or ticagrelor) after a recent acute coronary syndrome (ACS) or elective PCI were scheduled for platelet function assessment at 30–90 days post-discharge. Platelet function was assessed by whole blood impedance aggregometry (Multiplate®-Roche Diagnostics AG), HRPR was considered for ASPI test values > 862 AU*min (for ASA) and adenosine diphosphate (ADP) test values ≥417 AU*min (for ADP-antagonists). Fasting samples were obtained for main chemistry parameters and vitamin D level assessment. Our population is represented by 503 patients, who were divided according to vitamin D quartiles (≤9.1; 9.2–14.4; 14.5–21.7; >21.7 ng/ml). Lower vitamin D levels related with age (p = 0.04), diabetic status (p = 0.05), and previous coronary surgery (p = 0.007), therapy with beta-blockers and statins (p = 0.01 and p = 0.02). Vitamin D inversely related to the levels of total cholesterol (p = 0.01), triglycerides (p < 0.001), hemoglobin (p = 0.05), and HbA1c (p < 0.001). Significantly higher platelet reactivity was observed after platelet stimulation with ADP (p = 0.01), but not with other platelet activators. The prevalence of HRPR for ASA was low (1.2%) and not conditioned by Vitamin D levels (adjusted OR[95%CI] = 1.56[0.71–3.5], p = 0.27). HRPR with ADP-antagonists was observed in 26% of patients, and the rate increased with lower vitamin D quartiles (37.3% vs 22.2% vs 24.4% vs 20.2%, p = 0.005, adjusted OR[95%CI] = 1.23[1.02–1.49], p = 0.04). An absolute increase in HRPR with lower vitamin D levels was similarly observed among patients receiving ticagrelor (adjusted OR[95% CI] = 1.40[0.95–2.06], p = 0.08), and those on clopidogrel (adjusted OR[95%CI] = 1.31[0.99–1.75], p = 0.06). Thus, lower vitamin D levels are associated with higher platelet reactivity and impaired effectiveness of ADP-antagonists, while not influencing the effectiveness of ASA. Future studies will tell whether vitamin D supplementation can reduce platelet reactivity, overcoming the phenomenon of resistance to antiplatelet agents.

Relationship Between Glycoprotein IIIa Platelet Receptor Gene Polymorphism and Coronary Artery Disease

Glycoprotein IIb/IIIa (GP IIb/IIIa) is a key receptor for platelet aggregation and adhesion. We investigated whether a single-nucleotide polymorphism of GP IIIa subunit (Leu33Pro-PlA1/PlA2 allele) is associated with the extent of coronary artery disease (CAD) in a consecutive cohort of 1518 patients undergoing coronary angiography. Significant CAD was defined as at least a stenosis >50% and severe CAD as left main disease and/or trivessel disease. Additionally, carotid intima–media thickness (cIMT) was evaluated in 339 patients. The PlA2 allele was observed in 458 (30.2%) patients and associated with hypercholesterolemia (P = .03). No difference was observed in the prevalence of CAD (72.6% vs 70.1%, P = .29; adjusted odds ratio, OR [95% confidence interval, CI] = 0.85 [0.67-1.08], P = .19) and severe CAD (27.5% vs 26.5%, adjusted OR [95% CI] = 0.93 [0.72-1.19], P = .55). Furthermore, Leu33Pro polymorphism did not affect cIMT and the prevalence of carotid plaques. Therefore, this polymorphism cannot be regarded as a risk factor for coronary or carotid atherosclerosis.

Effect of diabetes mellitus on periprocedural myocardial infarction in patients undergoing coronary stent implantation

Diabetic patients undergoing percutaneous coronary interventions are still regarded as a very high risk category because of an increased platelet reactivity and risk of complications, especially in patients with inadequate glycaemic control. However, although its prognostic effect on long‐term outcome is well‐defined, still unclear is the effect of diabetes on the risk of periprocedural myocardial infarction in patients undergoing percutaneous coronary interventions, which was therefore the aim of our study.