| 1. |
- Alström, Ulrica, et al.
(författare)
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Platelet inhibition assessed with VerifyNow, flow cytometry and PlateletMapping in patients undergoing heart surgery
- 2009
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Ingår i: Thrombosis Research. - : Elsevier BV. - 0049-3848 .- 1879-2472. ; 124:5, s. 572-577
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: A substantial number of patients with coronary artery disease undergo cardiac surgery within five days of discontinuing anti-platelet treatment with aspirin and clopidogrel. The aims of this study were to describe the degree of platelet inhibition in patients with dual anti-platelet treatment scheduled for coronary artery bypass graft (CABG) surgery and to investigate whether the measured platelet inhibition correlated to intra- and postoperative risk for bleeding and transfusion requirements. MATERIAL AND METHODS: Sixty patients were included. Platelet inhibition was analysed with flow cytometry including phosphorylation status of the vasodilator-stimulated phosphoprotein (VASP-assay) and two bed-side analyzers, VerifyNow-System and PlateletMapping, a modified thrombelastograph. All 60 patients were analysed with VerifyNow and PlateletMapping, and 48 were analysed with flow cytometry and VASP-assay. RESULTS: There was a correlation between the ADP-receptor inhibition as measured by VASP-assay and VerifyNowP2Y(12) (r = -0.29, p<0.05), and between VASP-assay and the expression of P-selectin (r = 0.29, p<0.05) as measured by flow cytometry when platelets were stimulated with 5 microM ADP. VerifyNowP2Y(12) was the only measurement of platelet inhibition correlated to total blood loss (Spearman r = 0.29, p=0.03) and red blood cell transfusion (Spearman r = 0.43, p<0.01) requirements, although this might be confounded by aprotinin treatment. CONCLUSION: We found a modest agreement between the methods for preoperative platelet inhibition, though not for PlateletMapping-MA(ADP). There was a correlation between preoperative platelet inhibition measured by VerifyNowP2Y(12) and surgical blood loss or transfusion requirements. However, for the individual patient, preoperative use of VerifyNowP2Y(12) as an instrument to decide bleeding and transfusion risk does not seem helpful.
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| 2. |
- Alström, Ulrica, et al.
(författare)
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The platelet inhibiting effect of a clopidogrel bolus dose in patients on long-term acetylsalicylic acid treatment
- 2007
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Ingår i: Thrombosis Research. - : Elsevier BV. - 0049-3848 .- 1879-2472. ; 120:3, s. 353-359
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Addition of clopidogrel to patients treated with ASA has been shown to decrease the incidence of in-stent thrombosis after percutaneous coronary interventions. However, it has also been reported that up to 30% of patients do not achieve adequate platelet inhibition from standard dosages of ASA and clopidogrel. There is a demand for reliable methods to measure the individual platelet inhibiting effect of this combination therapy. MATERIALS AND METHODS: The primary aim of the present investigation was to compare three methods for evaluation of the platelet inhibiting effect of a clopidogrel bolus dose in patients on long-term acetylsalicylic acid treatment. Thirty patients presenting for coronary angiography/PCI were included. Two patients were excluded due to technical problems. All patients were on 75-100 mg ASA/day for at least 8 days. Blood samples were analysed before and 16 h after a 300 mg clopidogrel bolus dose. The platelet inhibiting effect was measured with (1) Whole blood flow cytometry (17 patients); (2) a bed-side test, Platelet Mapping assay for the thrombelastograph (28 patients); and (3) PFA (Platelet function analyser) -100 (26 patients). RESULTS: With flow cytometry, the percentage of platelets expressing P-selectin (p=0.03) on their surface decreased significantly after the bolus dose of clopidogrel. There was also a reduction of platelets binding fibrinogen when stimulated with ADP. A significantly (p=0.002) increased platelet inhibition could also be demonstrated with Platelet Mapping. PFA-100 could not measure any significant platelet inhibiting effect of clopidogrel. CONCLUSION: A significant platelet inhibition could be demonstrated with flow cytometry and the Platelet Mapping assay, but not with PFA-100. However, levels of response for the individual patient with these three methods were inconsistent. Further studies are needed to evaluate how the results correlate to the clinical risk of thrombosis and bleeding.
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| 3. |
- Braun, Oscar, et al.
(författare)
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Greater reduction of platelet activation markers and platelet-monocyte aggregates by prasugrel compared to clopidogrel in stable coronary artery disease
- 2008
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Ingår i: Thrombosis and Haemostasis. - 0340-6245 .- 2567-689X. ; 100:4, s. 626-633
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Tidskriftsartikel (refereegranskat)abstract
- Prasugrel, a novel P2Y(12) ADP-receptor antagonist, has been reported to achieve greater inhibition of platelet aggregation compared to clopidogrel as assessed by light transmission aggregometry. It was the objective of this study to investigate the effect of prasugrel on alternative markers of platelet activation in comparison to a high loading dose and the approved maintenance dose of clopidogrel. One hundred ten aspirin-treated patients with stable coronary artery disease were randomized to a loading dose (LD, day 1)/ maintenance dose (MD, days 2-29) of prasugrel 60 mg/10 mg or clopidogrel 600 mg/75 mg. Platelet activation markers were analyzed by whole blood flow cytometry pre-dose and at 2 and 24 hours after LD and pre-dose at 14 and 29 days. After stimulation with 20 muM ADP, 2 hours after LD, significantly lower expression of activated GPIIb/IIIa (4.3 vs. 21.8 [mean fluorescent intensity (MFI)], p < 0.001) and P-selectin (2.0 vs. 11.7 MFI, p < 0.001) along with decreased formation of platelet-monocyte aggregates (16.4% vs. 29.6% positive cells, p < 0.001) was observed with prasugrel versus clopidogrel. All these effects were maintained through 24 hours and during the MD period. In conclusion, prasugrel 60 mg LD and 10 mg MD inhibit several markers of platelet activation and the formation of platelet-monocyte aggregates more effectively than a 600 mg LD and 75 mg MD of clopidogrel. Attenuated platelet aggregation and reduced expression of platelet pro-coagulant and pro-inflammatory markers with prasugrel suggest the potential to reduce cardiovascular events both in the acute setting and in long-term treatment.
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| 4. |
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| 5. |
- Erlinge, David, et al.
(författare)
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Patients with poor responsiveness to thienopyridine treatment or with diabetes have lower levels of circulating active metabolite, but their platelets respond normally to active metabolite added ex vivo
- 2008
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Ingår i: Journal of the American College of Cardiology. - : Elsevier BV. - 0735-1097 .- 1558-3597. ; 52:24, s. 1968-77
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: We evaluated the prevalence and mechanism of poor responsiveness to clopidogrel and prasugrel in coronary artery disease patients with and without diabetes. BACKGROUND: Low platelet inhibition by clopidogrel is associated with ischemic clinical events. A higher 600-mg loading dose (LD) has been advocated to increase responsiveness to clopidogrel. METHODS: In this study, 110 aspirin-treated patients were randomized to double-blind treatment with clopidogrel 600 mg LD/75 mg maintenance dose (MD) for 28 days or prasugrel 60 mg LD/10 mg MD for 28 days. Pharmacodynamic (PD) response was evaluated by light transmission aggregometry and vasodilator-stimulated phosphoprotein phosphorylation. The PD poor responsiveness was defined with 4 definitions previously associated with worse clinical outcomes. Active metabolites (AM) of clopidogrel and prasugrel were measured. Clopidogrel AM was added ex vivo. RESULTS: The proportion of patients with poor responsiveness was greater in the clopidogrel group for all definitions at all time points from 1 h to 29 days. Poor responders had significantly lower plasma AM levels compared with responders. Patients with diabetes were over-represented in the poor-responder groups and had significantly lower levels of AM. Platelets of both poor responders and diabetic patients responded fully to AM added ex vivo. CONCLUSIONS: Prasugrel treatment results in significantly fewer PD poor responders compared with clopidogrel after a 600-mg clopidogrel LD and during MD. The mechanism of incomplete platelet inhibition in clopidogrel poor-responder groups and in diabetic patients is lower plasma levels of its AM and not differences in platelet P2Y(12) receptor function.
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| 6. |
- James, Stefan K., 1964-, et al.
(författare)
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Troponin-T and N-terminal pro-B-type natriuretic peptide predict mortality benefit from coronary revascularization in acute coronary syndromes : a GUSTO-IV substudy
- 2006
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Ingår i: Journal of the American College of Cardiology. - : Elsevier BV. - 0735-1097 .- 1558-3597. ; 48:6, s. 1146-1154
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: This study was designed to evaluate biomarkers for selection of patients with non-ST-segment elevation acute coronary syndromes (ACS) that derive mortality benefit from revascularization. BACKGROUND: Biomarkers are essential for identification of patients at increased risk, which may be reduced by revascularization. METHODS: During the initial 30 days, 2,340 patients of 7,800 (30%) with non-ST-segment elevation ACS in the GUSTO (Global Utilization of Strategies To open Occluded arteries)-IV trial underwent coronary revascularization. The 1-year mortality was calculated in 30-day survivors stratified by status of revascularization and levels of biomarkers. A propensity score for receiving revascularization was constructed and included in a survival analysis that also included the time point of revascularization as a time-dependent covariate. RESULTS: Elevation of troponin-T or N-terminal pro-B-type natriuretic peptide (NT-proBNP) was associated with a high mortality. In patients with either or both of these markers elevated, a lower mortality following revascularization was observed. In contrast, patients without elevation of these markers had low 1-year mortality without any reduction in mortality following revascularization. In fact, in patients with normal levels of both troponin-T and NT-proBNP, a significant increase in 1-year mortality after revascularization was observed. Elevation of C-reactive protein, interleukin-6, creatinine clearance, and ST-segment depression was also related to a higher mortality. However, independent of these markers, mortality was lower after revascularization. CONCLUSIONS: Markers of troponin-T and NT-proBNP not only assist in risk stratification of patients with non-ST-segment elevation ACS but also appear to identify patients who have a reduced mortality associated with early coronary revascularization.
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| 7. |
- James, Stefan K., 1964-, et al.
(författare)
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Usefulness of biomarkers for predicting long-term mortality in patients with diabetes mellitus and non-ST-elevation acute coronary syndromes (A GUSTO IV substudy)
- 2006
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Ingår i: American Journal of Cardiology. - : Elsevier BV. - 0002-9149 .- 1879-1913. ; 97:2, s. 167-172
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Tidskriftsartikel (refereegranskat)abstract
- The present study evaluated whether biomarkers of ischemia, inflammation, myocardial damage, and dysfunction are equally useful in patients who have diabetes mellitus (DM) for prediction of cardiac events in non-ST-elevation acute coronary syndrome (ACS). DM was present in 1,677 of 7,800 patients (21.5%) who had non-ST-elevation ACS and were included in the Fourth Global Utilization of Strategies To Open Occluded Arteries (GUSTO IV) trial. Creatinine, N-terminal pro-B-type natriuretic peptide (NT-pro-BNP), troponin T, C-reactive protein, and interleukin-6 were analyzed in serum samples that were obtained at a median of 9.5 hours from symptom onset. One-year mortality rates were 13.5% among patients who had DM (n = 227) and 6.9% among those who did not (n = 418, p < 0.001). The median level of NT-pro-BNP was 2 times as high in patients who had DM, whereas troponin T levels did not differ by DM status. Mortality increased with ascending quartiles of NT-pro-BNP, with 1-year mortality rates of 3.9% (n = 11) in the bottom quartile and 29% (n = 103) in the top quartile. In multivariable analyses, factors that were predictive of 1-year mortality in patients who did not have DM were also significant for those who did. Presence of ST depression > 0.5 mm had the highest odds ratio of 2.3 (95% confidence interval 1.2 to 4.6). NT-pro-BNP levels > 669 ng/L (odds ratio 2.0, 95% confidence interval 1.1 to 3.6) and interleukin-6 levels > 10 ng/L (odds ratio 1.9, 95% confidence interval 1.2 to 3.0) were significant biomarker predictors. In conclusion, DM confers a high long-term mortality in non-ST-elevation ACS. Despite a larger proportion of ST depression and increased levels of NT-pro-BNP and interleukin-6 at admission, these factors provide independent prognostic information that may improve risk stratification and guidance of treatment.
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| 8. |
- Jernberg, Tomas, et al.
(författare)
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Prasugrel achieves greater inhibition of platelet aggregation and a lower rate of non-responders compared with clopidogrel in aspirin-treated patients with stable coronary artery disease
- 2006
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Ingår i: European Heart Journal. - : Oxford University Press (OUP). - 0195-668X .- 1522-9645. ; 27:10, s. 1166-1173
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: This study was designed to compare the degree of inhibition of platelet aggregation (IPA) of prasugrel with that of clopidogrel in stable aspirin-treated patients with coronary artery disease (CAD). METHODS AND RESULTS: Subjects (n=101) were randomly assigned to the following loading dose (LD) (day 1)/maintenance dose (MD) (days 2-28) combinations: prasugrel, 40 mg/5 mg; 40 mg/7.5 mg; 60 mg/10 mg; 60 mg/15 mg; or clopidogrel, 300 mg/75 mg. Turbidometric platelet aggregation was measured at multiple timepoints during the study. At 4 h after dosing, with 20 microM ADP, both prasugrel LDs achieved significantly higher mean IPA levels (60.6% and 68.4 vs. 30.0%, respectively; all P<0.0001) and lower percentage (3 vs. 52%, P<0.0001) of pharmacodynamic non-responders (defined as IPA <20%) than clopidogrel. Prasugrel 10 and 15 mg MDs achieved consistently higher mean IPA than clopidogrel 75 mg at day 28 (all P<0.0001). At pre-MD on day 28, there were no non-responders in the 10 and 15 mg prasugrel group, compared with 45% in the clopidogrel group (P=0.0007). CONCLUSION: In this population, prasugrel (40-60 mg LD and 10-15 mg MD) achieves greater IPA and a lower proportion of pharmacodynamic non-responders compared with the approved clopidogrel dosing.
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| 9. |
- Johnston, Nina, et al.
(författare)
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Oxidized low-density lipoprotein as a predictor of outcome in patients with unstable coronary artery disease
- 2006
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Ingår i: International Journal of Cardiology. - : Elsevier BV. - 0167-5273 .- 1874-1754. ; 113:2, s. 167-173
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Tidskriftsartikel (refereegranskat)abstract
- Background: The prognostic value of circulating oxidized low-density lipoprotein (OxLDL) in patients with unstable coronary artery disease (CAD) is unknown. Methods: Plasma levels of OxLDL were measured in 433 patients with unstable CAD included in FRISC-II (Fragmin and fast Revascularisation in Instability in Coronary artery disease trial) and in 233 of these patients at follow-up 4-7 weeks later. Mortality and myocardial infarction (MI) at 2 years of follow-up was related to above (n 226) or below (n =207) the median level of OxLDL (76 U/L) at study entry. Results: After adjustment for other well-known predictors of risk, OxLDL levels > 76 U/L were associated with a higher risk for recurrent MI (Odds Ratio [95% CI]: 1.90 [1.05-3.39]). When patients were divided according to troponin T (TnT) status, the prognostic value of OxLDL was most evident in the TnT negative group with a risk of MI of 16.9% in patients with elevated OxLDL compared to 1.7% (p = 0.004) in those without. No association was found between levels of OxLDL and mortality. At follow-up levels of OxLDL were similar to levels during the acute phase unless patients were treated with statins in which levels were significantly lower. Conclusions: Elevated levels of OxLDL may identify patients with unstable CAD, at increased risk for future MI independent of other risk variables, particularly those without evidence of myocardial damage. OxLDL levels appear to be similar in patients during the unstable and stable phase of CAD unless statin therapy is initiated.
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| 10. |
- Mälarstig, Anders, et al.
(författare)
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Genetic variation in the interleukin-6 gene in relation to risk and outcomes in acute coronary syndrome
- 2007
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Ingår i: Thrombosis Research. - : Elsevier BV. - 0049-3848 .- 1879-2472. ; 119:4, s. 467-473
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The concept of inflammation in the acute coronary syndrome (ACS) is today well established. Interleukin-6 (IL-6), a pleiotropic, proinflammatory cytokine, seems to play an important role in the development and progression of ACS. AIM: The aim was to investigate whether IL6 polymorphisms are associated with patient/control status, outcome in patients with ACS and plasma concentrations of IL-6 and C-reactive protein (CRP). METHODS: Samples for citrated plasma and DNA were obtained on admission from 3027 patients with non-ST-elevation ACS in the FRISC-II study. A group of 447 healthy controls of similar age and gender as the patients was also recruited. Eight IL6 polymorphisms were genotyped and plasma concentrations of IL-6 and CRP measured in patients and controls. RESULTS: No associations between patient/control status, clinical outcome, ST-depression, troponin-T elevation or a history of myocardial infarction and IL6 polymorphisms were observed. In the full patient group, there was a trend towards association of the -572 G>C polymorphism with plasma concentrations of IL-6 (p=0.07). This association was statistically significant in patients with available high-sensitivity measurements of IL-6 (p=0.01). The -572 CG genotype was predictive for IL-6 levels above 5 ng/L in patients with a subsequent cardiovascular event, 2.3 (1.1-4.3) (adjusted odds ratio, 95% confidence interval). Comparison with data from HapMap showed that our panel of polymorphisms covered information on approximately 30 other IL6 variants. CONCLUSION: The -572 G>C and other polymorphisms in the study were not associated with outcome in ACS patients. However, the -572 CG genotype may contribute to a more distinct inflammatory response in patients with ACS.
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| 11. |
- Mälarstig, Anders, et al.
(författare)
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Raised Interleukin-10 is an Indicator of Poor Outcome and Enhanced Systemic Inflammation in Patients with Acute Coronary Syndrome
- 2008
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Ingår i: Heart. - : BMJ. - 1355-6037 .- 1468-201X. ; 94:6, s. 724-9
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To re-evaluate the relation between plasma interleukin-10 (IL-10) concentration at hospital admission and outcome and to investigate the impact of single nucleotide polymorphisms (SNP) in the IL-10 gene in patients with non-ST elevation acute coronary syndrome (ACS). DESIGN: Determination of IL-10 plasma concentrations and genotyping of SNPs in the IL-10 gene in a prospective trial of patients with ACS and in a group of healthy controls. PATIENTS: 3179 patients in the Fragmin and fast revascularisation during InStability in Coronary artery disease II (FRISC II) trial and 393 healthy controls. MAIN OUTCOME MEASURES: Mortality and incidence of myocardial infarction (MI) at 12 months. RESULTS: The median and interquartile ranges of IL-10 were 0.8 (0.5-1.0) pg/ml in healthy controls and 1.1 (0.7-1.9) pg/ml in patients (p<0.001). In patients, IL-10 predicted a crude risk increase of death/MI, with the highest risk observed in the fourth quartile (adjusted odds ratio 1.7 (95% confidence interval 1.2 to 2.3)). Adjustment for common risk indicators, including C-reactive protein and interleukin-6, weakened the association to a non-significant level. The 1170 CC genotype weakly predicted increased plasma concentrations of IL-10 in patients (p = 0.04) and in controls (p = 0.03), which was consistent with the modest association of this variant with coronary disease (p = 0.01). CONCLUSION: In contrast with some previous reports, we conclude that IL-10 reflects a proinflammatory state in patients with ACS and we therefore suggest that IL-10 is as effective a biomarker for the risk prediction of future cardiovascular events as other markers of systemic inflammation.
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| 12. |
- Oldgren, Jonas, 1964-, et al.
(författare)
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Lipoprotein-associated phospholipase A2 does not predict mortality or new ischaemic events in acute coronary syndrome patients
- 2007
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Ingår i: European Heart Journal. - : Oxford University Press (OUP). - 0195-668X .- 1522-9645. ; 28:6, s. 699-704
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Tidskriftsartikel (refereegranskat)abstract
- AIM: Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) has been suggested as an independent predictor of cardiovascular events in epidemiological studies. We sought to evaluate Lp-PLA(2) as a risk factor for future cardiovascular events in patients with acute coronary syndromes (ACS) and to elucidate the relationship between Lp-PLA(2) and other known risk markers in ACS patients and healthy control subjects. METHODS AND RESULTS: Blood samples were obtained at randomization in a random subset of ACS patients in the FRISC II (n = 1362) and GUSTO IV (n = 904) studies and in 435 apparently healthy controls of similar age and gender. Median Lp-PLA(2) (mass) levels were 305 ng/mL (FRISC II), 373 ng/mL (GUSTO IV), and 254 ng/mL (healthy controls). Time delay from symptom onset did not influence Lp-PLA(2) levels. In the FRISC II patients and healthy controls, Lp-PLA(2) was significantly correlated with cholesterol (r = 0.3), low-density lipoprotein (r = 0.4 and r = 0.3, respectively), and C-reactive protein (r = 0.08 and r = 0.1, respectively), all P < 0.01. Lp-PLA(2) was not correlated with age, interleukin-6, troponin T, or NT-proBNP in any of the three cohorts. There was no difference in the composite of death and myocardial infarction at 30 days (GUSTO IV) or 180 days (FRISC II) in relation to low, middle, and top tertiles of Lp-PLA(2) at randomization. In FRISC II, the 1 year mortality was 4.2, 4.2, and 4.8% in the low, middle, and top Lp-PLA(2) tertiles, respectively, P = 0.8. In GUSTO IV, 1 year mortality was 7.0, 8.3, and 9.6% in the low, middle, and top Lp-PLA(2) tertiles, respectively, P = 0.5. CONCLUSION: ACS patients had higher Lp-PLA(2) levels than healthy controls. Lp-PLA(2) was significantly correlated to lipid levels but only weakly correlated or unrelated to other well-established risk markers in ACS. The risk of future cardiovascular events or mortality was not related to Lp-PLA(2) levels in ACS patients. The biological role of Lp-PLA(2) and its role as a risk marker in ACS patients still remain unclear.
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| 13. |
- Oldgren, Jonas, 1964-, et al.
(författare)
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Xa inhibition and coagulation activity : the influence of prolonged dalteparin treatment and gender in patients with acute coronary syndrome and healthy individuals
- 2008
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Ingår i: American Heart Journal. - : Elsevier BV. - 0002-8703 .- 1097-6744. ; 155:3, s. 493.e1-
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: We evaluated coagulation activity in relation to gender in patients with acute coronary syndromes and in healthy individuals of similar age, and related coagulation activity to levels of Xa inhibition during dalteparin treatment. METHODS: Serial blood samples were obtained from 555 (172 women) of 2267 patients in the Scandinavian FRISC II study, and a single sample in 457 (151 women) apparently healthy age- and sex-matched individuals. After randomization, all patients received dalteparin 120 IU/kg s.c. (maximum 10,000 IU) twice daily for 5 to 7 days inhospital and thereafter placebo (n = 285) or sex- and weight-adjusted doses of dalteparin (5000 or 7500 IU) twice daily (n = 270) for 3 months. RESULTS: Before randomization, 96% of the patients had open-label anticoagulation with unfractionated heparin or dalteparin. Therapeutic anti-Xa levels (> 0.5 IU/mL) were found in 74%, 55%, 58%, and 33% of the dalteparin-treated patients at randomization, 2 days, 4 to 7 weeks, and 3 months, respectively, and were significantly related to lower levels of coagulation activity, ie, factor VIIa, prothrombin fragment 1+2, and D-dimer, during prolonged treatment. Female patients had higher anti-Xa levels than men at randomization (median 0.69 vs 0.60 IU/mL, P = .01) and at 2 days (0.65 vs 0.59 IU/mL, P < .001). Female patients had also significantly higher levels of all 3 coagulation markers at randomization, 2 days, 4 to 7 weeks, and 3 and 6 months. Similarly, healthy women had higher prothrombin fragment 1+2 levels (median 1.19 vs 0.94 nmol/L) and D-dimer levels than men (26 vs 21 microg/L) (both P < .001). CONCLUSIONS: Despite weight-adjusted dosing, female patients reached higher anti-Xa levels, suggesting increased sensitivity to dalteparin treatment. Healthy women and female patients also had higher coagulation activity, which might increase the risk of thrombus formation. The large proportion of patients with subtherapeutic anti-Xa during prolonged dalteparin treatment may reflect poor compliance and could thus contribute to the gradual loss of clinical efficacy.
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| 14. |
- Varenhorst, Christoph, et al.
(författare)
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Assessment of P2Y(12) inhibition with the point-of-care device VerifyNow P2Y12 in patients treated with prasugrel or clopidogrel coadministered with aspirin
- 2009
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Ingår i: American Heart Journal. - : Elsevier BV. - 0002-8703 .- 1097-6744. ; 157:3, s. 562.e1-9
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Variability in response to thienopyridines has led to the development of point-of-care devices to assess adenosine diphosphate (ADP)-induced platelet aggregation. These tests need to be evaluated in comparison to reference measurements of P2Y(12) function during different thienopyridine treatments. METHODS: After a run-in on 75 mg aspirin, 110 subjects were randomized to double-blind treatment with clopidogrel 600 mg loading dose (LD)/75 mg maintenance dose (MD) or prasugrel 60 mg LD/10 mg MD. Antiplatelet effects were evaluated by VerifyNow P2Y12 (VN-P2Y12) device (Accumetrics, San Diego, CA), vasodilator-stimulated phosphoprotein (VASP) phosphorylation assay, and light transmission aggregometry (LTA). Prasugrel's and clopidogrel's active metabolite concentration were also determined. RESULTS: Dose- and time-dependent inhibition of P2Y(12) was evident with VN-P2Y12. There was strong correlation with VN-P2Y12 and VASP or LTA for all treatments through a wide range of P2Y(12) function. At high levels of P2Y(12) inhibition, platelet function measured by VN-P2Y12 was maximally inhibited and could not reflect further changes seen with VASP or LTA methods. Correlation was also observed between exposure to clopidogrel's active metabolite and VN-P2Y12 during MD and LD, whereas it was observed only with prasugrel MD. CONCLUSION: The VN-P2Y12 correlated strongly with inhibition of P2Y(12) function, as measured with either VASP or LTA. VN-P2Y12 also correlated to exposure to the active metabolite of prasugrel and clopidogrel up to levels associated with assumed saturation of the P2Y(12) receptor.
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| 15. |
- Varenhorst, Christoph, 1977-, et al.
(författare)
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Genetic variation of CYP2C19 affects both pharmacokinetic and pharmacodynamic responses to clopidogrel but not prasugrel in aspirin-treated patients with coronary artery disease
- 2009
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Ingår i: European Heart Journal. - : Oxford University Press (OUP). - 0195-668X .- 1522-9645. ; 30:14, s. 1744-1752
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Tidskriftsartikel (refereegranskat)abstract
- Aims The metabolic pathways leading to the formation of prasugrel and clopidogrel active metabolites differ. We hypothesized that decreased CYP2C19 activity affects the pharmacokinetic and pharmacodynamic response to clopidogrel but not prasugrel. Methods and results Ninety-eight patients with coronary artery disease (CAD) taking either clopidogrel 600 mg loading dose (LD)/75 mg maintenance dose (MD) or prasugrel 60 mg LD/10 mg MD were genotyped for variation in six CYP genes. Based on CYP genotype, patients were segregated into two groups: normal function (extensive) metabolizers (EM) and reduced function metabolizers (RM). Plasma active metabolite concentrations were measured at 30 min, 1, 2, 4, and 6 h post-LD and during the MD period on Day 2, Day 14, and Day 29 at 30 min, 1, 2, and 4 h. Vasodilator-stimulated phosphoprotein (VASP) and VerifyNow P2Y12 were measured predose, 2, and 24 +/- 4 h post-LD and predose during the MD period on Day 14 +/- 3 and Day 29 +/- 3. For clopidogrel, active metabolite exposure was significantly lower (P = 0.0015) and VASP platelet reactivity index (PRI, %) and VerifyNow P2Y(12) reaction unit (PRU) values were significantly higher (P < 0.05) in the CYP2C19 RM compared with the EM group. For prasugrel, there was no statistically significant difference in active metabolite exposure or pharmacodynamic response between CYP2C19 EM and RM. Variation in the other five genes demonstrated no statistically significant differences in pharmacokinetic or pharmacodynamic responses. Conclusion Variation in the gene encoding CYP2C19 in patients with stable CAD contributes to reduced exposure to clopidogrel's active metabolite and a corresponding reduction in P2Y(12) inhibition, but has no significant influence on the response to prasugrel.
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| 16. |
- Wallentin, Lars, 1943-, et al.
(författare)
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Prasugrel achieves greater and faster P2Y12receptor-mediated platelet inhibition than clopidogrel due to more efficient generation of its active metabolite in aspirin-treated patients with coronary artery disease
- 2008
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Ingår i: European Heart Journal. - : Oxford University Press (OUP). - 0195-668X .- 1522-9645. ; 29:1, s. 21-30
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: P2Y(12) receptor antagonism and platelet inhibition by prasugrel vs. clopidogrel were investigated in patients with stable coronary artery disease. METHODS AND RESULTS: One hundred and ten aspirin treated subjects were randomized to double-blind treatment with clopidogrel (n = 55) 600 mg loading dose (LD) and 75 mg maintenance dose (MD) or prasugrel (n = 55) 60 mg LD and 10 mg MD for 28 days. Concentrations of prasugrel and clopidogrel active metabolites were determined. Platelet aggregation to 20 microM adenosine diphosphate, measured by light transmission aggregometry, was reported as maximal platelet aggregation (MPA). P2Y(12) function was assessed by the vasodilator-stimulated phosphoprotein assay and reported as platelet reactivity index (PRI). The same pharmacodynamic measurements were performed after ex vivo addition of clopidogrel's active metabolite. At 2 h post-LD, mean MPA was 31 vs. 55%, and mean PRI 8.3 vs. 55.9% for prasugrel and clopidogrel, respectively (P < 0.001). During MD on day 14 and 28, mean MPA was 42 vs. 54% and mean PRI was 25 vs. 51%, respectively (P < 0.001). Peak level of the active metabolite and P2Y(12) inhibition occurred earlier and was greater with prasugrel (P < 0.001). Mean area under the time-concentration curve (AUC; microM.h) of the respective active metabolite was higher with prasugrel vs. clopidogrel post-LD (1.11 vs. 0.24) and post-MD (0.16 vs. 0.062). Ex vivo addition of clopidogrel's active metabolite further reduced PRI in all patients whose platelets were not already maximally inhibited. CONCLUSION: In aspirin-treated subjects with coronary artery disease, prasugrel 60/10 mg provides faster onset and greater inhibition of P2Y(12) receptor-mediated platelet aggregation than clopidogrel 600/75 mg, because of greater and more efficient generation of the active metabolite.
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