Rotational thromboelastometry for diagnosis of fibrinolysis induced by urokinase in an in-vitro model.

Fibrinolysis can be abnormally activated in several critical care settings but it's often misdiagnosed by standard laboratory tests. Although rotational thromboelastometry can assess the whole coagulative process, its ability to detect fibrinolysis has been questioned. Aim of this study was to investigate the ability of thromboelastometry in detecting induced fibrinolysis in an in-vitro model. Whole blood samples were taken from 18 healthy volunteers. Each sample was split and added with increasing urokinase concentrations till to reach 0, 50, 75 and 100 IU/ml. Thromboelastometry tests, extem and aptem, were performed on the obtained samples. If significant lysis at 50 IU/ml was recorded, also 10, 25 and 35 IU/ml drug concentrations were tested. No lytic effects were detected in 10 IU/ml samples. Lysis variables were the most sensitive in detecting fibrinolysis even at 25 IU/ml (P < 0.05). Clot firmness parameters were also affected by urokinase, but only at the two highest drug concentrations (P < 0.05). Extem/aptem ratio enhanced the sensitivity of these parameters only if lysis was more marked. Analysing groups of different lysis severity, the time to achieve maximum clot firmness could anticipate an ongoing fulminant or intermediate lysis with 100% sensitivity and 100% specificity (P < 0.05) when lower than 1341.5 s. Rotational thromboelastometry could detect fibrinolysis when it was induced in vitro by 25 IU/ml urokinase or more. Apart from the parameters specific for lysis, time to achieve maximum clot firmness appeared as the earliest indicator of fibrinolysis with high sensitivity and specificity especially if a more intense lysis was going on.

Impact of cardiovascular burden on coagulation pathway in apparently healthy women planning oocyte donation.

BACKGROUND: Hormonal fertility treatments are associated with increased coagulation factors inducing procoagulant milieu and possibly thrombotic risk. OBJECTIVE: To assess coagulation by ROTEM and coagulation tests in apparently healthy infertile women before oocyte donation procedure. METHODS: We enrolled 51 women (Assisted Reproductive Technology Centre, Florence). ROTEM and coagulation parameters were assessed before the start of infertility treatment. RESULTS: We divided women in 3 groups according to the number of cardiovascular risk factors: Group A (n = 10), Group B (n = 16), and Group C (n = 25). By considering ROTEM Extem test, a significantly increased of MCF, TPI, and G were observed in groups B (p = 0.005, p = 0.03, and p = 0.007) and C (p = 0.01, p = 0.05, and p = 0.005) in comparison to group A. As regards ROTEM Intem test, the TPI and G values were significantly higher in groups B and C in comparison to group A (p < 0.01). MCF by Fibtem test significantly increased in groups B and C than in group A (p = 0.004 and p = 0.002, respectively). FVIII, vWF:Ag and D-dimer values significantly increase according to the presence of≥2 risk factors. CONCLUSIONS: Data from coagulative assessment permit to sensitively identify women with potentially procoagulable state, which represents a risk factor of thromboembolic event during hormone treatment.

Platelet Reactivity in Hepatitis C Virus-Infected Patients on Dual Antiplatelet Therapy for Acute Coronary Syndrome.

Background Coronary artery disease (CAD) has been recognized as a serious and potentially life-threatening complication of Hepatitis C Virus (HCV) infection. High on-treatment platelet reactivity has been associated with high risk of ischemic events in patients with CAD, but data regarding the association with HCV infection are still lacking. This post hoc analysis aims to assess high on-treatment platelet reactivity, severity of CAD, and long-term outcomes of patients with acute coronary syndrome (ACS) who were infected with HCV. Methods and Results Patients with ACS who were infected with HCV (n=47) were matched to patients with ACS and without HCV (n=137) for age, sex, diabetes mellitus, hypertension, and renal function. HCV-infected patients with ACS had higher levels of platelet reactivity (ADP10-light transmittance aggregometry, 56±18% versus 44±22% [P=0.002]; arachidonic acid-light transmittance aggregometry, 25±21% versus 16±15% [P=0.011]) and higher rates of high on-treatment platelet reactivity on clopidogrel and aspirin compared with patients without HCV. Moreover, HCV-infected patients with ACS had higher rates of multivessel disease (53% versus 30%; P=0.004) and 3-vessel disease (32% versus 7%; P<0.001) compared with patients without HCV. At long-term follow-up, estimated rates of major adverse cardiovascular events (cardiac death, nonfatal myocardial infarction, and ischemia-driven revascularization) were 57% versus 34% (P=0.005) in HCV- and non-HCV-infected patients with ACS, respectively. In addition, thrombolysis In Myocardial Infarction (TIMI) major bleeding rates were higher in HCV-infected patients (11% versus 3%; P=0.043) compared with noninfected patients. Multivariable analysis demonstrated that HCV infection was an independent predictor of high on-treatment platelet reactivity, severity of CAD, and long-term outcome. Conclusions In this hypothesis-generating study, patients with ACS and HCV infection showed increased on-treatment platelet reactivity, more severe CAD, and worse prognosis compared with patients without HCV.

Clinical Implications of "Tailored" Antiplatelet Therapy in Patients With Chronic Total Occlusion.

Background Clopidogrel nonresponsiveness is a prognostic marker after percutaneous coronary intervention. Prasugrel and ticagrelor provide a better platelet inhibition and represent the first-line antiplatelet treatment in acute coronary syndrome. We sought to assess the prognostic impact of high platelet reactivity (HPR) and the potential clinical benefit of a "tailored" escalated or changed antiplatelet therapy in patients with chronic total occlusion. Methods and Results From Florence CTO-PCI (chronic total occlusion-percutaneous coronary intervention) registry, platelet function assessed by light transmission aggregometry, was available for 1101 patients. HPR was defined by adenosine diphosphate test ≥70% and optimal platelet reactivity by adenosine diphosphate test <70%. The endpoint of the study was long-term cardiac survival. Patients were stratified according to light transmission aggregometry results: optimal platelet reactivity (82%) and HPR (18%). Means for the adenosine diphosphate test were 44±16% versus 77±6%, respectively. Three-year survival was significantly higher in the optimal platelet reactivity group compared with HPR patients (95.3±0.8% versus 86.2±2.8%; P<0.001). With the availability of new P2Y12 inhibitors, a deeper platelet inhibition (46±17%) and similar survival to the optimal platelet reactivity group were achieved in patients with HPR on clopidogrel therapy after escalation. Conversely, HPR on clopidogrel therapy "not switched" was associated with cardiac mortality (hazard ratio 2.37; P=0.003) after multivariable adjustment. Conclusions HPR on treatment could be a modifiable prognostic marker by new antiaggregants providing a deeper platelet inhibition associated with clinical outcome improvement in complex chronic total occlusion patients. A "tailored" antiplatelet therapy, also driven by the entity of platelet inhibition, could be useful in these high risk setting patients.

Patient blood management in cardiac surgery: The "Granducato algorithm".

BACKGROUND: Patients undergoing cardiac surgery are subject to severe alterations of the coagulation system. The four cardiac surgery centers in Tuscany (Italy) structured and shared an algorithm (Granducato Patient Blood Management algorithm, G-PBMa) with predefined interventions for patient blood management. The aim of the study is to analyze the impact of that algorithm on the transfusion needs and bleeding-related outcomes in a large patient population. METHODS: Multicenter retrospective observational study on 3839 patients undergoing cardiac surgery at the four cardiac centers in Tuscany. The G-PBMa was released at the end of 2015 and it was structured in three parts: pre-, intra-, and post-operative. The year 2014, before the G-PBMa (1955 patients) and the year 2016 (1884 patients) after the G-PBMa in place were compared. Logistic regression analyses were used. RESULTS: The main changes introduced were the routine application of viscoelastic tests in bleeding patients (+72%) and the use of fibrinogen and prothrombin complex concentrate (+67%). The G-PBMa resulted in a significant reduction in the overall transfusion rate and in the transfusion rate of the separate blood products (relative risk for transfusions: 0.75, 95% confidence interval 0.65-0.85, P = 0.001). For preoperative hemoglobin values of between 8 and 10 g/dL, the absolute difference in RBC transfusion rate before and after the G-PBMa introduction ranged around 15%-17%. The G-PBMa introduction determined lower (P = 0.02) chest drain blood loss, lower (P = 0.001) postoperative acute kidney injury and shorter (P = 0.001) hospital stay. CONCLUSIONS: The G-PBMa was effective in reducing blood loss, transfusion requirements, and resulted in a better outcome.

On-Treatment Platelet Reactivity is a Predictor of Adverse Events in Peripheral Artery Disease Patients Undergoing Percutaneous Angioplasty.

OBJECTIVES: Few data are available on the association between a different entity of platelet inhibition on antiplatelet treatment and clinical outcomes in patients with peripheral artery disease (PAD). The aim of this study was to evaluate the degree of on-treatment platelet reactivity, and its association with ischaemic and haemorrhagic adverse events at follow up in PAD patients undergoing percutaneous transluminal angioplasty (PTA). METHODS: In this observational, prospective, single centre study, 177 consecutive patients with PAD undergoing PTA were enrolled, and treated with dual antiplatelet therapy with aspirin and a P2Y12 inhibitor. Platelet function was assessed on blood samples obtained within 24 h from PTA by light transmission aggregometry (LTA) using arachidonic acid (AA) and adenosine diphosphate (ADP) as agonists of platelet aggregation. High on-treatment platelet reactivity (HPR) was defined by LTA ≥ 20% if induced by AA, and LTA ≥ 70% if induced by ADP. Follow up was performed to record outcomes (death, major amputation, target vessel re-intervention, acute myocardial infarction and/or myocardial revascularisation, stroke/TIA, and bleeding). RESULTS: HPR by AA and HPR by ADP were found in 45% and 32% of patients, respectively. During follow up (median duration 23 months) 23 deaths (13%) were recorded; 27 patients (17.5%) underwent target limb revascularisation (TLR), two (1.3%) amputation, and six (3.9%) myocardial revascularisation. Twenty-four patients (15.6%) experienced minor bleeding. On multivariable analysis, HPR by AA and HPR by ADP were independent predictors of death [HR 3.8 (1.2-11.7), p = .023 and HR 4.8 (1.6-14.5), p = .006, respectively]. The median value of LTA by ADP was significantly lower in patients with bleeding complications than in those without [26.5% (22-39.2) vs. 62% (44.5-74), p < .001). LTA by ADP ≤ 41% was independently associated with bleeding HR 14.6 (2.6-24.0), p = .001] on multivariable analysis. CONCLUSIONS: In this study a high prevalence of on-clopidogrel and aspirin high platelet reactivity was found, which was significantly associated with the risk of death. Conversely, a low on-clopidogrel platelet reactivity was associated with a higher risk of bleeding. These results document that the entity of platelet inhibition is associated with both thrombotic and bleeding complications in PAD patients.

Residual thrombin potential predicts cardiovascular death in acute coronary syndrome patients undergoing percutaneous coronary intervention.

INTRODUCTION: Thrombin generation (TG) is a central step of the coagulation system involved in hemostatic and thrombotic roles. Scarce data evaluating in the acute phase the association between TG and the risk of cardiovascular death of acute coronary syndrome (ACS) patients are available, in the era of percutaneous coronary intervention (PCI) and stenting with the use of dual antiplatelet treatment. MATERIALS AND METHODS: We investigated TG in 292 ACS patients undergoing PCI with stent implantation on dual antiplatelet treatment. Venous samples were obtained 12-24h after PCI. TG was assessed using the Calibrated Automated Thrombogram (CAT). RESULTS: At two years of follow-up, 57 out of 292 patients (19.5%) died from cardiovascular causes. Higher values of endogenous thrombin potential (ETP) [1115.9 (705-1441.3) vs 940.2 (666.0-1253.1), p=0.049], peak [176.1 (80.5-259.4) vs 107.3 (59.9-181.1), p=0.002] and velocity index [61.75 (21.03-97.88) vs 25.64 (11.95-50.90), p<0.001] were observed in relation to survival patients. At the multivariate model adjusted for the Global Registry of Acute Coronary Events risk score, the association between TG and cardiovascular death remained significant for ETP [OR (95% CI): 2.58 (1.10-6.03), p=0.029], peak [OR (95%CI): 3.27 (1.35-7.92), p=0.009] and velocity index [OR (95% CI): 3.06 (1.27-7.39), p=0.013]. This result was confirmed after adjustment for high on-treatment platelet reactivity [ETP: OR (95% CI) 2.35 (1.11-5.00), p=0.027; peak: OR (95% CI) 2.42 (1.13-5.15), p=0.022; velocity index: OR (95% CI) 2.43 (1.14-5.20), p=0.022]. CONCLUSIONS: ACS patients with a residual TG after PCI and stent implantation have a significantly higher risk of long-term cardiovascular death. These results might be useful in improving risk stratification for ACS patients and support the need of a tailored antithrombotic therapy.

Plasma levels of direct oral anticoagulants in real life patients with atrial fibrillation: Results observed in four anticoagulation clinics.

INTRODUCTION: Direct oral anticoagulant (DOAC) intra- and inter-individual variability was previously reported, but its magnitude is still considered negligible for patient management. OBJECTIVE: To evaluate inter- and intra-individual variability in real-world atrial fibrillation patients on dabigatran, rivaroxaban or apixaban in four Italian anticoagulation clinics and to assess the correlation between DOAC plasma concentration and creatinine-clearance (CrCl). MATERIALS AND METHODS: A total of 330 consecutive patients were enrolled, of which 160 were on dabigatran (70 and 90 taking 150 mg or 110 mg twice-daily, respectively), 71 on rivaroxaban (37 and 34 taking 20mg or 15 mg once-daily) and 99 on apixaban (73 and 26 taking 5mg or 2.5mg twice-daily). Blood was taken at trough and peak within the first month (15-25 days) of treatment. Diluted-thrombin-time (dTT) calibrated for dabigatran and anti-FXa calibrated for rivaroxaban or apixaban was performed. RESULTS: Mean inter-individual variability expressed as overall CV values for all drugs was lower at peak (CV=46%) than at trough (CV=63%). Mean CV% intra-individual variability was 36.6% at trough and 34.0% at peak. Correlation with CrCl was poor for all drugs and only dabigatran at trough showed a significant correlation. CONCLUSION: This multicenter study confirms high DOAC inter-individual variability that cannot be explained by the rate of renal clearance to which the three DOAC were subjected since the correlation with CrCl was relatively poor. This poor correlation suggests caution in using CrCl as the sole laboratory parameter to indirectly evaluate residual circulating DOAC.

A time course study of high on treatment platelet reactivity in acute coronary syndrome male patients on dual antiplatelet therapy.

INTRODUCTION: Limited data are available on the natural history of high on treatment platelet reactivity (HPR) by arachidonic acid and ADP - markers of unfavorable prognosis in acute coronary syndrome patients -. MATERIAL AND METHODS: In a cohort of acute coronary syndrome male patients (n=101), we evaluated the time-course of HPR by ADP (platelet aggregation by 10µM ADP≥70%) and arachidonic acid (platelet aggregation by 1mmol arachidonic acid≥20%) measuring platelet function in the acute phase (T0), at 6months (T1) and 1year (T2). RESULTS: We identified persistent (HPR at T0,T1 and T2), acute non persistent (HPR only at T0), and late (HPR only at T1 or T2). Patients with persistent HPR by ADP were more frequently with higher values of BMI. Patients carrying CYP2C19*2 variant were more prevalent in the group of persistent HPR (33%). Significant higher values of immature platelet fraction and high immature platelet fraction at 6 and 12months and mean platelet volume were present in patients with late HPR. Immature platelet fraction was the only variable significantly associated with late HPR by ADP at multivariate analysis (OR=1.6 (1.08-2.3), p=0.016). Patients with persistent HPR by arachidonic acid were more frequently diabetics. Immature platelet fraction at 6months and high immature platelet fraction at 6 and 12months were the parameters associated with late HPR by AA (OR=1.4 (1.0-1.9), p=0.036; OR=1.5 (1.08-2.4), p=0.05; OR=4.9 (1.3-18.8), p=0.018, respectively). CONCLUSIONS: About 25% of 101 patients has persistent HPR; they are more frequently diabetics, overweight or carriers of CYP2C19*2. The occurrence of an inflammatory state, indicated by the increase of immature platelet fraction, is associated with the occurrence of late HPR.

Platelet function tests: a comparative review.

In physiological hemostasis a prompt recruitment of platelets on the vessel damage prevents the bleeding by the rapid formation of a platelet plug. Qualitative and/or quantitative platelet defects promote bleeding, whereas the high residual reactivity of platelets in patients on antiplatelet therapies moves forward thromboembolic complications. The biochemical mechanisms of the different phases of platelet activation - adhesion, shape change, release reaction, and aggregation - have been well delineated, whereas their complete translation into laboratory assays has not been so fulfilled. Laboratory tests of platelet function, such as bleeding time, light transmission platelet aggregation, lumiaggregometry, impedance aggregometry on whole blood, and platelet activation investigated by flow cytometry, are traditionally utilized for diagnosing hemostatic disorders and managing patients with platelet and hemostatic defects, but their use is still limited to specialized laboratories. To date, a point-of-care testing (POCT) dedicated to platelet function, using pertinent devices much simpler to use, has now become available (ie, PFA-100, VerifyNow System, Multiplate Electrode Aggregometry [MEA]). POCT includes new methodologies which may be used in critical clinical settings and also in general laboratories because they are rapid and easy to use, employing whole blood without the necessity of sample processing. Actually, these different platelet methodologies for the evaluation of inherited and acquired bleeding disorders and/or for monitoring antiplatelet therapies are spreading and the study of platelet function is strengthening. In this review, well-tried and innovative platelet function tests and their methodological features and clinical applications are considered.

Non-traumatic splenic rupture on dual antiplatelet therapy with aspirin and ticagrelor after stenting for acute coronary syndrome.

We report a case of non-traumatic splenic rupture in a 57-year-old man on dual antiplatelet therapy (DAPT) with aspirin and ticagrelor, seven months after percutaneous coronary intervention and drug-eluting stent implantation for non-ST elevation myocardial infarction. No splenic abnormalities were found at histopathological analysis after splenectomy, and no history of recent trauma was reported. Once restarted, DAPT after splenectomy, assessment of platelet function was performed by light transmittance aggregometry, showing a profound inhibition of platelet function by adenosine diphosphate, arachidonic acid, and collagen. Taking into account the bleeding risk associated with low on-treatment platelet reactivity, and to switch the patient from ticagrelor to a less potent P2Y12 inhibitor such as clopidogrel, cytochrome P450, genetic polymorphisms accounting for clopidogrel response variability were analyzed. The polymorphisms associated with lower response (CYP2C19*2, CYP2C19*3) were absent. Therefore, ticagrelor was withdrawn, and DAPT was continued with aspirin and clopidogrel. Rupture of the spleen may occur in the absence of major trauma or previous splenic diseases, and could be a complication of antithrombotic treatments. Moreover, low on-treatment platelet reactivity during DAPT is emerging as a possible risk factor for bleeding complications, so underlining the usefulness of assessing platelet function in special conditions to ensure that the patient receives the best tailored antiplatelet therapy. .

Residual platelet reactivity to predict long-term clinical outcomes after clopidogrel loading in patients with acute coronary syndromes: comparison of different cutoff values by light transmission aggregometry from the responsiveness to clopidogrel and stent thrombosis 2-acute coronary syndrome (RECLOSE 2-ACS) study.

The aim of this study was the identification of the optimal cutoff value of high residual platelet reactivity (HRPR) assessed by light transmission aggregometry (LTA) in the responsiveness to clopidogrel and stent thrombosis 2-acute coronary syndrome (RECLOSE 2-ACS) patient cohort to discriminate patients with and without major adverse cardiac events (MACE) and cardiac death at 2 years. The RECLOSE 2-ACS study included 1,789 patients with ACS who underwent LTA after clopidogrel loading. A post hoc cutoff value for HRPR was defined with the ROC curve and the Youden index and compared with the protocol-defined cutoff of 70 %. By ROC analysis, 63 % resulted the optimal cutoff value to predict both MACE and cardiac death at 2 years follow-up. A significant sensitivity improvement for the ROC-based cutoff value was noted (p < 0.001), at the price of lower specificity and predictive accuracy. The latter were 81 % for MACE and 85 % for cardiac death with the 70 % cutoff, while the respective figures were 73 and 75 % with the 63 % cutoff. The areas under the curve were virtually identical with the 70 and 63 % cutoffs both for MACE (0.71) and cardiac death (0.79). A residual platelet reactivity cutoff of 70 % by LTA, compared to the ROC-based cutoff of 63 %, allows for the identification of a subset of patients at very high risk of adverse ischemic events, making LTA-ADP test more acceptable in clinical practice for the identification of subjects at risk than other platelet function assays with broader definitions of HRPR.

Global platelet hyperreactivity and elevated C-reactive protein levels predict long term mortality in STEMI patients.

BACKGROUND: Data on long term - more than 1-year - prognostic value of global platelet reactivity (G-HPR) - by adenosine diphosphate (ADP) and arachidonic acid (AA) - in patients with STEMI undergoing PCI are limited. High C-reactive protein (CRP) levels have been suggested to be associated with post-PCI atherothrombotic events. Our aim was to evaluate the long-term prognostic impact of G-HPR and CRP levels in STEMI patients. METHODS AND RESULTS: We evaluated 494 STEMI patients (366 M/128 F; age: 65.8 ± 12.4 yrs) undergoing PCI with stent implantation. At a median follow-up of 2.3 years (1.09-4.06), in 58 patients we documented cardiovascular death (11.7%). Platelet reactivity was assessed by light transmission aggregometry by 1mM AA (AA-LTA) and 10 microM ADP (ADP-LTA). By the ROC curve analysis, 17%, 52% and 12 mg/L were found to be the values of AA-LTA, ADP-LTA and CRP associated with the highest specificity and sensitivity for death. G-HPR was defined as the presence of both AA-LTA ≥ 17% and ADP-LTA ≥ 52%. At Cox regression analysis adjusted for age, sex, cardiovascular risk factors, multivessel disease, ejection fraction, renal insufficiency, G-HPR and elevated CRP levels were associated with long-term mortality [HR=1.78 (95%CI 1.04-3.03), p=0.036 and HR=2.91 (1.54-5.52, p=0.001), respectively]. The contemporary presence of G-HPR and elevated CRP levels was associated with the highest risk of death [HR=5.1 (95%CI 1.9-13.4), p=0.001]. CONCLUSION: G-HPR and CRP are independent long-term prognostic markers in STEMI patients. The contemporary presence of G-HPR and CRP identifies a subgroup of patients at significantly higher risk of cardiovascular death.

Platelet and leukocyte ROS production and lipoperoxidation are associated with high platelet reactivity in Non-ST elevation myocardial infarction (NSTEMI) patients on dual antiplatelet treatment.

INTRODUCTION: High platelet reactivity (HPR) on dual antiplatelet therapy is a risk factor for adverse vascular events in acute coronary syndrome (ACS) patients. Several studies have shown that reactive oxygen species (ROS) may be involved in modulating platelet function. METHODS: In Non-ST elevation myocardial infarction (NSTEMI) patients (n = 132) undergoing percutaneous coronary intervention (PCI) on dual antiplatelet therapy blood samples were collected within 24 h from 600 mg clopidogrel loading dose. Platelet reactivity was assessed by light transmission aggregometry using 10 µM ADP, 1 mM arachidonic acid (AA) and 2 µg/ml collagen. ROS production and lipoperoxidation of circulating cells were determined. by FACSCanto flow cytometry. In these patients, we investigated: 1) the relationship between the amount of cellular ROS production/lipoperoxidation and platelet reactivity; 2) the association of cellular ROS production with the presence of high platelet reactivity to ADP and arachidonic acid (AA). RESULTS: Significantly higher levels of platelet and leukocyte-derived ROS were detected in 49 dual HPR (with platelet aggregation by AA ≥ 20% and by ADP ≥ 70%) compared to non-HPR patients (n = 49) [Platelet-derived ROS: +142%; Leukocyte-derived ROS: +14%, p < 0.0001]. Similarly, dual HPR patients had significantly higher platelet and leukocyte lipoperoxidation than non-HPR patients [Platelet lipoperoxidation: +131%; Leukocyte lipoperoxidation: +14%, p < 0.001]. After adjustment for several potential confounders, platelet-, leukocyte-derived ROS and platelet and leukocyte lipoperoxidation remained significantly associated to dual HPR. The significant predictors of ADP, AA, and collagen platelet aggregation at multiple linear regression analysis, after adjusting for age, cardiovascular risk factors, procedural parameter, medications, leukocyte number and MPV, were platelet-, leukocyte-derived ROS and platelet and leukocyte lipoperoxidation (p < 001). CONCLUSIONS: Our results demonstrate that in NSTEMI patients on dual antiplatelet therapy, ROS production by and lipoperoxidation of platelets are strictly correlated to the different pathways of platelet aggregation and that ROS production and lipoperoxidation of platelets and leukocytes are predictors of non responsiveness to dual antiplatelet treatment.

Perioperative assessment of platelet function by Thromboelastograph Platelet Mapping in cardiovascular patients undergoing non-cardiac surgery.

UNLABELLED: Five percent of patients on dual antiplatelet therapy after coronary artery stent implantation will need non-cardiac surgery within the first year of therapy, and many more will need surgery later on. A function assay that evaluates platelet reactivity and inhibition by drug therapy is beneficial for such patients. Platelet Mapping assay (PM) using the TEG analyzer was tested in surgical patients. After IRB approval, 60 patients on combined aspirin and clopidogrel therapy were consented and enrolled. The TEG maximal amplitude (MA) and the percentage (%) platelet inhibition were recorded and analyzed. Fifty-seven patients (mean age 65.7 ± 10.9 years) had preoperative data only. Distribution of preoperative ADP (43.6 ± 24.4%) and AA inhibition (52.8 ± 30.2%) was determined, as well as for the preoperative MA ADP (43.1 ± 15.9 mm) and MA AA (37.2 ± 19.6 mm), showing an offset of the effect of both medications starting from day 3. Patients with complete pre- and postoperative data were stratified depending on duration off antiplatelet therapy (≤3 days, 3-7 days and >7 days): n = 27, ADP % preop inhibition (43.2 ± 21.6%), ADP % postop inhibition (32.3 ± 18.3%), p = 0.048. Distribution of immediate pre- and post- ADP and AA % inhibitions, showing a possible reduction in Δ of inhibition for clopidogrel at 3 days, were also assessed. CONCLUSION: According to the findings, the TEG PM assay might be a feasible approach to objectively evaluate the effects of aspirin and clopidogrel during the perioperative period and potentially guide drug management.

High on-treatment platelet reactivity by ADP and increased risk of MACE in good clopidogrel metabolizers.

High on-treatment platelet reactivity (HPR) by ADP, which primarily reflects the effect of thienopyridines, has been found to be an independent predictor of ischemic events in patients with acute coronary syndrome (ACS) on dual antiplatelet therapy. CYP2C19*2 is associated with HPR by ADP. The aim of our study was to evaluate if high on-clopidogrel platelet reactivity (HPR) by ADP is associated with an increased risk of major adverse coronary events (MACE) after ACS independent of CYP2C19*2 allele, i.e. whether genotyping patients for CYP2C19*2 polymorphism is sufficient to identify those to be switched to novel antiplatelets. A total of 1187 patients were included (CYP2C19 *1/*1 n = 892; *1/*2 n = 264; *2/*2 n = 31); 76 MACE (CV death and non-fatal MI) were recorded in non-carriers of CYP2C19*2 (8.5%) and 39 in carriers of CYP2C19*2 (13.2%). At the landmark analysis in the first 6 months, HPR by ADP and CYP2C19*2 allele were both significantly and independently associated with MACE [HPR by ADP: HR = 2.0 (95% CI 1.2-3.4), p = 0.01; CYP2C19*2 allele: HR = 2.3 (95% CI 1.3-3.9), p = 0.003]. At the land mark analysis from 7 to 12 months, only HPR by ADP remained significantly associated with the risk of MACE [HPR by ADP: HR = 2.7 (95% CI 1.4-5.3), p = 0.003; CYP2C19*2: HR = 0.8 (95% CI 0.2-1.1), p = ns]. CYP2C19*2 allele and HPR by ADP are both independently associated with an increased risk of MACE in the first 6 months after ACS. HPR by ADP is associated with an increased risk until 12 months of follow-up. Therefore, both phenotype and genotype are clinically relevant for the evaluation of the antiplatelet effect of clopidogrel and for the prognostic stratification of ACS patients.

Index measured at an intermediate altitude to predict impending acute mountain sickness.

PURPOSE: Acute mountain sickness (AMS) is a neurological disorder that may be unpredictably experienced by subjects ascending at a high altitude. The aim of the present study was to develop a predictive index, measured at an intermediate altitude, to predict the onset of AMS at a higher altitude. METHODS: In the first part, 47 subjects were investigated and blood withdrawals were performed before ascent, at an intermediate altitude (3440 m), and after acute and chronic exposition to high altitude (Mount Everest Base Camp, 5400 m (MEBC1 and MEBC2)). Parameters independently associated to the Lake Louise scoring (LLS) system, including the self-reported and the clinical sections, and coefficients estimated from the model obtained through stepwise regression analysis were used to create a predictive index. The possibility of the index, measured after an overnight stay at intermediate altitude (Gnifetti hut, 3647 m), to predict AMS (defined as headache and LLS ≥ 4) at final altitude (Capanna Margherita, 4559 m), was then investigated in a prospective study performed on 44 subjects in the Italian Alps. RESULTS: During the expedition to MEBC, oxygen saturation, hematocrit, day of expedition, and maximum velocity of clot formation were selected as independently associated with LLS and were included in the predictive index. In the Italian Alps, subjects with a predictive index value ≥ 5.92 at an intermediate altitude had an odds ratio of 8.1 (95% confidence limits = 1.7-38.6, sensitivity = 85%, specificity = 59%) for developing AMS within 48 h of reaching high altitude. CONCLUSION: In conclusion, a predictive index combining clinical and hematological parameters measured at an intermediate step on the way to the top may provide information on impending AMS.