New interest in fibrinogen as an ischemic risk factor.

Platelet-fibrin clot formation is a key process in acute arterial thrombosis. The relationship between thrombin-induced platelet-fibrin clot strength (P-FCS) and fibrinogen levels in patients with cardiovascular disease (CVD) and COVID-19 has not been studied. In thhe current study, the contribution of fibrinogen to P-FCS has been explored in healthy subjects (n=157), patients hospitalized with COVID-19 (n=116), and patients with CVD (n=93) using thrombelastography (TEG 6s) with citrate cartridge. We found that thrombin-induced P-FCS, fibrin clot strength (F-CS) and fibrinogen levels (FLEV) were higher among patients with CVD and COVID-19 compared to HS (p<0,05 for all) and highest among patients with COVID-19. P-FCS, an established risk factor for post-PCI ischemic event occurrences, was associated with both F-CS and FLEV (R2=0.67, p<0.001 for both comparisons. These data indicate that fibrinogen levels strongly influence the viscoelastic strength of the platelet-fibrin clot, fibrinogen may be an important driving factor for arterial thrombosis in the presence of potent platelet inhibition and may be as equally important a risk factor as high platelet reactivity. Since P-FCS is significantly associated with fibrinogen levels, the role of fibrinogen as a risk factor for arterial ischemic event occurrences should be further studied to improve antithrombotic therapy personalization.

Early assessment of the pharmacokinetic and pharmacodynamic effects following acetylsalicylic acid loading: toward a definition for acute therapeutic response.

Despite decades of investigations, the optimal assessment of the "therapeutic response" to early after loading dose of acetylsalicylic acid (ASA) remains unclear. Limited information is available on the relation between pharmacodynamic (PD) and pharmacokinetic (PK) measurements assessed immediately after ASA administration. Serial PD and PK analyses were performed immediately after a single 162 or 650 mg dose of chewed and swallowed ASA in ten healthy adults. ASA response was defined as > 95% inhibition of serum thromboxane (Tx)B2, < 550 aspirin reaction units (ARU) by VerifyNow Aspirin (VN) test, and ≤ 20% arachidonic acid (AA)-induced platelet aggregation (PA). Correlation analyses between PK and PD measurements and receiver operating characteristic (ROC) curve analyses were performed. ASA response measured by VN test and AA-induced PA was achieved within 30 min of ASA administration. A correlation was observed between ARU and AA-induced maximum PA (r = 0.69, p < 0.001), serum TxB2 (r = 0.74 and p < 0.001), and serum TxB2 inhibition (r = 0.79, p < 0.001). In ROC curve analyses, ≤ 558 ARU and ≤ 7% AA-induced PA were associated with > 95% inhibition of TxB2. 686 ng/ml plasma ASA cut-off point was associated with > 95% inhibition of serum TxB2, ≤ 7% 1 mM AA-induced PA, and ≤ 585 ARU. A modest ~ 50% inhibition of TxB2 inhibition was associated with marked inhibition of 1 mM AA-induced platelet aggregation by LTA. Our analyses demonstrated important relationships between pharmacodynamic, and pharmacokinetic parameters measured immediately following oral ASA and cutoff values for ARU and AA-induced PA that is associated with > 95% inhibition of serum TxB2.

Utility of VerifyNow to assess the immediate pharmacodynamic response of chewed and swallowed aspirin: comparison with aggregometry.

VerifyNow (VN) test is a less laborious method to assess pharmacodynamics (PD) compared to light transmittance aggregometry (LTA). VN assay has not been used to study the immediate PD effects of acetylsalicylic acid (ASA). Ten healthy volunteers were randomly assigned to a single 162 or 650 mg dose of chewed and swallowed ASA. Pharmacodynamic and pharmacokinetic measurements were performed at baseline and serially up to 60 min after ASA administration. Onset by VN was 20 ± 7 min with 162 mg and 13 ± 7 min with 650 mg ASA (p = .07). Onset by 1 mM AA-induced PA was 13 ± 12 min with 162 mg and 7 ± 3 min with 650 mg ASA (p=NS). VN correlated with AA-induced PA (r = 0.80, p < .001) and serum TxB2 levels (r = 0.76, p < .001). 95% inhibition of serum TxB2 was achieved at 38 ± 22 min and 22 ± 8 min with the 162 and 650 mg ASA, respectively (p = .08). The onset and extent of the antiplatelet effect of 650 mg ASA is numerically faster and greater than the 162 mg dose. VN identifies the onset, extent, and dose response to ASA therapy. The ease of using VN should facilitate multicenter PD investigations of ASA.

Aspirin (acetylsalicylic acid) is an important drug widely used to prevent adverse ischemic events in patients with cardiovascular disease. Platelet aggregation and thromboxane B₂ levels in blood samples by complex laboratory methods are used to assess platelet response to aspirin. VerifyNow assay is a simple laboratory test that has not been used to assess the immediate effect of aspirin. In this study, conducted in 10 healthy volunteers, we compared the immediate platelet response to aspirin by serially assessing platelet aggregation by aggregometry and VerifyNow assay, and thromboxane B₂ levels. We also measured plasma levels of acetylsalicylic acid and salicylic acid. Our study demonstrated that the VerifyNow Aspirin test identifies the onset, extent, and dose-response to aspirin therapy. The ease of using the VerifyNow test should facilitate multicenter pharmacodynamic investigations of aspirin.

Prognostic impact of hypercoagulability and impaired fibrinolysis in acute myocardial infarction.

AIMS: Atherothrombotic events are influenced by systemic hypercoagulability and fibrinolytic activity. The present study evaluated thrombogenicity indices and their prognostic implications according to disease acuity. METHODS AND RESULTS: From the consecutive patients undergoing percutaneous coronary intervention (PCI), those with thrombogenicity indices (n = 2705) were grouped according to disease acuity [acute myocardial infarction (AMI) vs. non-AMI]. Thrombogenicity indices were measured by thromboelastography (TEG). Blood samples for TEG were obtained immediately after insertion of the PCI sheath, and TEG tracing was performed within 4 h post-sampling. Major adverse cardiovascular events (MACE, a composite of cardiovascular death, non-fatal myocardial infarction, and non-fatal stroke) were evaluated for up to 4 years. Compared with non-AMI patients, AMI patients had higher platelet-fibrin clot strength [maximal amplitude (MA): 66.5 ± 7.8 vs. 65.3 ± 7.2 mm, P < 0.001] and lower fibrinolytic activity [clot lysis at 30 min (LY30): 0.9 ± 1.8% vs. 1.1 ± 1.9%, P < 0.001]. Index AMI presentation was associated with MA [per one-mm increase: odds ratio (OR): 1.024; 95% confidence interval (CI): 1.013-1.036; P < 0.001] and LY30 (per one% increase: OR: 0.934; 95% CI: 0.893-0.978; P = 0.004). The presence of high platelet-fibrin clot strength (MA ≥68 mm) and low fibrinolytic activity (LY30 < 0.2%) was synergistically associated with MACE occurrence. In the multivariable analysis, the combined phenotype of 'MA ≥ 68 mm' and 'LY30 < 0.2%' was a major predictor of post-PCI MACE in the AMI group [adjusted hazard ratio (HR): 1.744; 95% CI: 1.135-2.679; P = 0.011], but not in the non-AMI group (adjusted HR: 1.031; 95% CI: 0.499-2.129; P = 0.935). CONCLUSION: AMI occurrence is significantly associated with hypercoagulability and impaired fibrinolysis. Their combined phenotype increases the risk of post-PCI atherothrombotic event only in AMI patients. These observations may support individualized therapy that targets thrombogenicity for better outcomes in patients with AMI. CLINICAL TRIAL REGISTRATION: Gyeongsang National University Hospital (G-NUH) Registry, NCT04650529.

Deficiency of MMP1a (Matrix Metalloprotease 1a) Collagenase Suppresses Development of Atherosclerosis in Mice: Translational Implications for Human Coronary Artery Disease.

[Figure: see text].

Metformin use in patients hospitalized with COVID-19: lower inflammation, oxidative stress, and thrombotic risk markers and better clinical outcomes.

Diabetes mellitus (DM) is associated with a greater risk of COVID-19 and an increased mortality when the disease is contracted. Metformin use in patients with DM is associated with less COVID-19-related mortality, but the underlying mechanism behind this association remains unclear. Our aim was to explore the effects of metformin on markers of inflammation, oxidative stress, and hypercoagulability, and on clinical outcomes. Patients with DM on metformin (n = 34) and metformin naïve (n = 41), and patients without DM (n = 73) were enrolled within 48 h of hospital admission for COVID-19. Patients on metformin compared to naïve patients had a lower white blood cell count (p = 0.02), d-dimer (p = 0.04), urinary 11-dehydro thromboxane B2 (p = 0.01) and urinary liver-type fatty acid binding protein (p = 0.03) levels and had lower sequential organ failure assessment score (p = 0.002), and intubation rate (p = 0.03), fewer hospitalized days (p = 0.13), lower in-hospital mortality (p = 0.12) and lower mortality plus nonfatal thrombotic event occurrences (p = 0.10). Patients on metformin had similar clinical outcomes compared to patients without DM. In a multiple regression analysis, metformin use was associated with less days in hospital and lower intubation rate. In conclusion, metformin treatment in COVID-19 patients with DM was associated with lower markers of inflammation, renal ischemia, and thrombosis, and fewer hospitalized days and intubation requirement. Further focused studies are required to support these findings.

Serial assessment of thrombogenicity and hemodynamics in patients with type II diabetes in a clinical research unit: Evidence for circadian variations in clot formation.

BACKGROUND: Circadian fluctuations in thrombogenicity and hemostasis play a role in acute cardiovascular thrombotic events occurring in the early morning hours. There is a lack of data assessing thrombogenicity, platelet function, and hemodynamics to investigate diurnal variations in a high cardiovascular risk population. METHODS: This was an exploratory, single-center study conducted in aspirin-treated patients with Type II Diabetes Mellitus (T2DM) (n = 37) with documented vascular disease and/or multiple cardiovascular risk factors. Hemodynamic monitoring and blood sample collection for thromboelastography (TEG) and platelet function testing were done serially at 7-9 AM (morning), 7-9 PM (evening), 11 PM-1 AM (night), and at 5-7 AM (awakening). RESULTS: R-value measured by TEG was shorter during awakening hours than during the night and day hours (p < 0.05). There were no changes in platelet reactivity in response to arachidonic acid, adenosine diphosphate, and collagen between time points. Pulse pressure (PP) was highest during awakening hours (p < 0.05). CONCLUSION: Study findings provide a mechanistic explanation for increased thrombotic events observed in the early waking hours among diabetics with multiple cardiovascular risk factors. The role of chronotherapy in reducing coagulability and PP to improve clinical outcomes should be explored.

The role of viscoelastic testing in assessing peri-interventional platelet function and coagulation.

We carried out a literature search in MEDLINE (PubMed) and EMBASE literature databases to provide a concise review of the role of viscoelastic testing in assessing peri-interventional platelet function and coagulation. The search identified 130 articles that were relevant for the review, covering the basic science of VHA and VHA in clinical settings including cardiac surgery, cardiology, neurology, trauma, non-cardiac surgery, obstetrics, liver disease, and COVID-19. Evidence from these articles is used to describe the important role of VHAs and platelet function testing in various peri-interventional setups. VHAs can help us to comprehensively assess the contribution of platelets and coagulation dynamics to clotting at the site-of-care much faster than standard laboratory measures. In addition to standard coagulation tests, VHAs are beneficial in reducing allogeneic transfusion requirements and bleeding, in predicting ischemic events, and improving outcomes in several peri-interventional care settings. Further focused studies are needed to confirm their utility in the peri-interventional case.

PAR1 (Protease-Activated Receptor 1) Pepducin Therapy Targeting Myocardial Necrosis in Coronary Artery Disease and Acute Coronary Syndrome Patients Undergoing Cardiac Catheterization: A Randomized, Placebo-Controlled, Phase 2 Study.

OBJECTIVE: Arterial thrombosis leading to ischemic injury worsens the prognosis of many patients with cardiovascular disease. PZ-128 is a first-in-class pepducin that reversibly inhibits PAR1 (protease-activated receptor 1) on platelets and other vascular cells by targeting the intracellular surface of the receptor. The TRIP-PCI (Thrombin Receptor Inhibitory Pepducin in Percutaneous Coronary Intervention) trial was conducted to assess the safety and efficacy of PZ-128 in patients undergoing cardiac catheterization with intent to perform percutaneous coronary intervention. Approach and Results: In this randomized, double-blind, placebo-controlled, phase 2 trial, 100 patients were randomly assigned (2:1) to receive PZ-128 (0.3 or 0.5 mg/kg), or placebo in a 2-hour infusion initiated just before the start of cardiac catheterization, on top of standard oral antiplatelet therapy. Rates of the primary end point of bleeding were not different between the combined PZ-128 doses (1.6%, 1/62) and placebo group (0%, 0/35). The secondary end points of major adverse coronary events at 30 and 90 days did not significantly differ but were numerically lower in the PZ-128 groups (0% and 2% in the PZ-128 groups, 6% and 6% with placebo, p=0.13, p=0.29, respectively). In the subgroup of patients with elevated baseline cardiac troponin I, the exploratory end point of 30-day major adverse coronary events + myocardial injury showed 83% events in the placebo group versus 31% events in the combined PZ-128 drug groups, an adjusted relative risk of 0.14 (95% CI, 0.02-0.75); P=0.02. CONCLUSIONS: In this first-in-patient experience, PZ-128 added to standard antiplatelet therapy appeared to be safe, well tolerated, and potentially reduced periprocedural myonecrosis, thus providing the basis for further clinical trials. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02561000.

Defining platelet response to acetylsalicylic acid: the relation between inhibition of serum thromboxane B2 and agonist-induced platelet aggregation.

Arachidonic acid (AA)-induced platelet aggregation (PA) and serum thromboxane B2 (TxB2) inhibition are widely used to indicate cyclooxygenase-1 activity and the antiplatelet effect of acetylsalicylic acid (ASA). Despite decades of investigations, the relation between these measurements remains unclear. We sought to evaluate the relation between AA-PA and serum TxB2 inhibition. We serially measured AA-PA (conventional aggregation), serum TxB2, plasma ASA and salicylic acid (SA) (liquid chromatography-mass spectrometry), and urinary 11-dehydro thromboxane B2 (u11-dh TxB2) (enzyme-linked immunosorbent assay) levels at 10 times over 24 hours in seventeen healthy volunteers receiving a single dose of 162 mg chewed and swallowed ASA (n = 6), 50 mg inhaled ASA (n = 6), or 100 mg inhaled ASA (n = 5) (ClinicalTrials.gov Identifier: NCT04328883, April 1, 2020). Baseline variability was more pronounced with serum TxB2 (31-680 ng/mL) as compared to maximal AA-PA (65-81%) and u11-dh TxB2 (1556-4440 pg/mg creatinine). The relation between serum TxB2 inhibition and AA-PA was stepwise; after 30-40% inhibition of serum TxB2, AA-PA fell to < 5%. By receiver operating characteristic curve analysis using AA-PA < 5% to define aspirin responsiveness, serum TxB2 inhibition > 49% and u11-dh TxB2 < 1520 pg/mg creatinine met the definition. Our study demonstrates a non-linear relation between serum TxB2 inhibition and AA-PA. Aggregation was nil once TxB2 inhibition reached > 49%. Moreover, these results suggest that the definition of > 95% inhibition of serum TxB2 to indicate the level of platelet COX-1 inhibition needed for clinical efficacy may be overestimated and should be re-considered in future translational research investigations that attempt to link the clinical efficacy of ASA with a laboratory measurement cutoff.

Clinical validation of AggreGuide A-100 ADP, a novel assay for assessing the antiplatelet effect of oral P2Y12 antagonists.

In this prospective, 3-arm, repeated-measure multicenter investigation in 280 patients with cardiovascular risk factors, platelet aggregation was measured with the novel AggreGuide A-100 ADP (A-100 ADP) and VerifyNow (VN)-PRU assays at baseline, and after United States Food and Drug Administration approved loading and 7 days maintenance doses of clopidogrel (n = 94), prasugrel (n = 43) or ticagrelor, (n = 143). Based on the predetermined cutoff values of < 4.7 platelet activity index with A-100 ADP assay to indicate antiplatelet response, more than 91% of patients met the criteria following loading and maintenance doses of prasugrel and more than 84% patients met the criteria following loading and maintenance doses of ticagrelor whereas only 32% and 51% of patients met the criteria following loading and maintenance doses of clopidogrel, respectively. The total percent agreement between the A-100 ADP and VN-PRU assays was 89%. The A-100 ADP assay, which includes whole blood in motion, performs comparably to the VN-PRU assay in a study of patients with cardiovascular risk factors treated with P2Y12 inhibitors possessing known differences in antiplatelet potencies. Trial registration ClinicalTrials.gov Identifier: NCT3111420.

Detailed thrombogenicity phenotyping and 1 year outcomes in patients undergoing WATCHMAN implantation: (TARGET-WATCHMAN) a case-control study.

The relation of device related thrombosis (DRT) and major bleeding after left atrial appendage closure (LAAC) to laboratory thrombosis and hemostasis markers has not been studied. We performed a prospective case control study to identify clinical characteristics and laboratory markers in patients who developed DRT and major bleeding following WATCHMAN LAAC. Thromboelastography, platelet aggregation (PA), urinary 11-dehydrothromboxane B2 (UTX), fibrinogen, D-dimer, thrombin time and von Willebrand factor activity were determined at baseline, immediately following, and at 45 and 180 days post-LAAC (n = 32) and outcomes were followed for 1 year. Baseline characteristics and thrombogenic profiles of patients with and without DRT and/or BARC bleeding were compared. Mean age was 76 ± 8 years and CHADS2 VASc score was 4.4 ± 1.4. There were 3 DRTs (2 within 6 months, and 1 at 12 months), 4 Type 3A BARC bleeds, and 2 non-cardiac deaths. Patients with DRT had higher baseline thrombin-induced platelet-fibrin clot strength (68.0 ± 1.8 vs. 62.7 ± 4.7 mm, p = 0.06); FCS (35.6 ± 6.0 vs. 24.4 ± 6.6 mm, p = 0.009); and D-dimer (1712 ± 2330 vs. 283 ± 213 ng/mL, p = 0.001). At baseline, 5 patients had all 3 factors associated with high thrombotic risk and 2 experienced a DRT within 6 months. Patients with Type 3A BARC bleeding had lower baseline collagen-induced and 45-day ADP-induced PA (p < 0.01 for both). DRT following LAAC was associated with a baseline prothrombogenic profile whereas bleeding was associated with low platelet reactivity. These preliminary findings warrant further validation and have future implications on patient selection and adjunctive antithrombotic therapy following LAAC.Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT03040622 .

Noncanonical Matrix Metalloprotease 1-Protease-Activated Receptor 1 Signaling Drives Progression of Atherosclerosis.

OBJECTIVE: Protease-activated receptor-1 (PAR1) is classically activated by thrombin and is critical in controlling the balance of hemostasis and thrombosis. More recently, it has been shown that noncanonical activation of PAR1 by matrix metalloprotease-1 (MMP1) contributes to arterial thrombosis. However, the role of PAR1 in long-term development of atherosclerosis is unknown, regardless of the protease agonist. APPROACH AND RESULTS: We found that plasma MMP1 was significantly correlated (R=0.33; P=0.0015) with coronary atherosclerotic burden as determined by angiography in 91 patients with coronary artery disease and acute coronary syndrome undergoing cardiac catheterization or percutaneous coronary intervention. A cell-penetrating PAR1 pepducin, PZ-128, currently being tested as an antithrombotic agent in the acute setting in the TRIP-PCI study (Thrombin Receptor Inhibitory Pepducin-Percutaneous Coronary Intervention), caused a significant decrease in total atherosclerotic burden by 58% to 70% (P<0.05) and reduced plaque macrophage content by 54% (P<0.05) in apolipoprotein E-deficient mice. An MMP1 inhibitor gave similar beneficial effects, in contrast to the thrombin inhibitor bivalirudin that gave no improvement on atherosclerosis end points. Mechanistic studies revealed that inflammatory signaling mediated by MMP1-PAR1 plays a critical role in amplifying tumor necrosis factor α signaling in endothelial cells. CONCLUSIONS: These data suggest that targeting the MMP1-PAR1 system may be effective in tamping down chronic inflammatory signaling in plaques and halting the progression of atherosclerosis.

"Blueprinting" thrombogenicity and antithrombotic drug response at the bedside in patients presenting emergently with symptoms of acute stroke.

Early assessment of thrombogenicity and antithrombotic drug effects may be important for therapeutic decision making in patients presenting with acute stroke. In this prospective, single center, pilot study, a bedside thrombelastography assay (TEG6s) was used to measure thrombogenicity and antithrombotic drug response in serial patients presenting emergently with symptoms of acute stroke (n = 90). TEG6s measures were compared against diagnosis obtained by NIH Stroke Scale/Score and imaging. Acute ischemic stroke (AIS) was diagnosed in 30 patients, intracerebral hemorrhage (ICH) in 19, transient ischemic attack (TIA) in 10 and stroke mimic (SM) in 31. Patients with AIS had a higher prevalence of A-Fib (33.3% vs. 11.6%, p = 0.01), and ACE inhibitor use (56.3% vs. 21.6%, p < 0.001) compared to combined non-AIS group. Time to initial clot formation (R) was shorter in AIS vs. TIA, ICH, and SM (p < 0.05). Comparing patients with AIS and combined non-AIS group the AUC for R was 0.83 (cut point of ≤ 4.8, sensitivity = 67%; specificity = 84%, p < 0.001). In AIS patients, 46% had suboptimal response (< 30% MAAA inhibition) to aspirin and 80% of patients on P2Y12 therapy had high platelet reactivity (> 50% ADP-induced platelet aggregation). Patients receiving tissue plasminogen activator had significant reduction in clot strength and near complete lysis at 30 min which normalized within 2 h after treatment (p < 0.001 for both). The rapid bedside measurement of thrombogenicity and antithrombotic drug effects is feasible in patients presenting with symptoms of acute stroke. Our preliminary data suggest that AIS is associated with faster ex-vivo clot formation, and poor antiplatelet response. Future study of the TEG6s to "blueprint" hemostasis is warranted in the stroke population.

Thromboembolism after WATCHMANTM in a clopidogrel non-responder: A case for concern?

Atrial fibrillation (AF) is associated with an increased risk of stroke and thromboembolism (TE). The WATCHMANTM left atrial appendage (LAA) closure device is indicated to reduce the risk of TE from the LAA in patients with non-valvular AF. Here, we present a case of a patient with device-related thrombus who suffered a TE event two months after WATCHMANTM LAA closure and two weeks after switching from aspirin plus warfarin to aspirin plus clopidogrel therapy. Laboratory investigation identified the patient to be hypercoagulable and to be a non-responder to clopidogrel therapy. We discuss the potential role of platelet function testing to prevent device-related thrombi.

Thromboxane inhibition during concurrent therapy with low-dose aspirin and over-the-counter naproxen sodium.

Aspirin is the dominant antiplatelet therapy for cardiovascular disease. Naproxen is frequently used in aspirin-treated patients and may influence the antiplatelet effect of aspirin. We evaluated the pharmacodynamic interaction (lower bound of the one-sided 95% CI for serum TxB2 inhibition < 95%) between 220 mg immediate-release naproxen sodium (once or twice daily) and 81 mg daily immediate release aspirin at various dosing intervals. There was no interaction during the first day of concurrent treatment. After 10 days, irrespective of the timing and dose of naproxen in relation to aspirin dosing, a pharmacodynamic interaction occurred which persisted after discontinuing naproxen. In the control group (aspirin alone), the lower bound for serum TxB2 inhibition was > 98% at all time points. The clinical relevance of these observations remains unknown and merits further investigation since over-the-counter naproxen is widely used to relieve pain by individuals taking low dose aspirin for cardioprotection. CLINICAL TRIAL REGISTRATION: NCT02229461.

Evaluation of potential antiplatelet effects of CSL112 (Apolipoprotein A-I [Human]) in patients with atherosclerosis: results from a phase 2a study.

CSL112 (Apolipoprotein A-I [Human]), an infusible, plasma-derived apolipoprotein A-I, is being developed to reduce cardiovascular events following acute myocardial infarction (AMI). A predecessor compound (CSL111) demonstrated a potential antiplatelet effect. A phase 2a multicentre, randomised, single-ascending dose study in patients with stable atherosclerotic disease receiving dual antiplatelet therapy (DAPT) assessed the potential additive effects of CSL112 administration on platelet function and increase bleeding risk in the subacute period after AMI. Patients (n = 44) on aspirin (75-325 mg/day) and either clopidogrel (75 mg/day, n = 37) or prasugrel (10 mg/day, n = 7) for > 30 days alongside standard-of-care therapy were randomised to a single dose of placebo or CSL112: 1.7, 3.4, or 6.8 g. Light transmission aggregometry was used to assess platelet aggregation in response to 2 mM arachidonic acid, 5 and 20 µM adenosine diphosphate, and 4 µg/mL collagen, pre-dose (baseline) and up to 48 h post-dosing. Compared to placebo, CSL112 had no clinically meaningful time- or dose-dependent effects on maximum platelet aggregation in response to any agonist, by either dose or renal function subgroup (p > 0.05). Coagulation parameters showed little variation over time or between treatment groups (p > 0.05). CSL112, when co-administered with standard DAPT, did not significantly influence platelet aggregation in response to agonists and is, therefore, not expected to significantly increase bleeding risk when administered with antiplatelet therapies.

Implantable Cardioverter-Defibrillators for Primary Prevention in Patients With Ischemic or Nonischemic Cardiomyopathy: A Systematic Review and Meta-analysis.

BACKGROUND: Implantable cardioverter-defibrillators (ICDs) have a role in preventing cardiac arrest in patients at risk for life-threatening ventricular arrhythmias. PURPOSE: To compare ICD therapy with conventional care for the primary prevention of death of various causes in adults with ischemic or nonischemic cardiomyopathy. DATA SOURCES: MEDLINE, Cochrane Central Register of Controlled Trials, Google Scholar, and EMBASE databases, as well as several Web sites, from 1 April 1976 through 31 March 2017. STUDY SELECTION: Randomized controlled trials, published in any language, comparing ICD therapy with conventional care and reporting mortality outcomes (all-cause, sudden, any cardiac, or noncardiac) in the primary prevention setting. DATA EXTRACTION: 2 independent investigators extracted study data and assessed risk of bias. DATA SYNTHESIS: Included were 11 trials involving 8716 patients: 4 (1781 patients) addressed nonischemic cardiomyopathy, 6 (4414 patients) ischemic cardiomyopathy, and 1 (2521 patients) both types of cardiomyopathy. Mean follow-up was 3.2 years. An overall reduction in all-cause mortality, from 28.26% with conventional care to 21.37% with ICD therapy (hazard ratio [HR], 0.81 [95% CI, 0.70 to 0.94]; P = 0.043), was found. The magnitude of reduction was similar in the cohorts with nonischemic (HR, 0.81 [CI, 0.72 to 0.91]) and ischemic (HR, 0.82 [CI, 0.63 to 1.06]) disease, although the latter estimate did not reach statistical significance. The rate of sudden death fell from 12.15% with conventional care to 4.39% with ICD therapy (HR, 0.41 [CI, 0.30 to 0.56]), with a similar magnitude of reduction in patients with ischemic (HR, 0.39 [CI, 0.23 to 0.68]) and those with nonischemic disease (HR, 0.44 [CI, 0.17 to 1.12]). Noncardiac and any cardiac deaths did not differ significantly by treatment. LIMITATION: Heterogeneous timing of ICD placement; heterogeneous pharmacologic and resynchronization co-interventions; trials conducted in different eras; adverse events and complications not reviewed. CONCLUSION: Overall, primary prevention with ICD therapy versus conventional care reduced the incidence of sudden and all-cause death. PRIMARY FUNDING SOURCE: None.

Cell-Penetrating Pepducin Therapy Targeting PAR1 in Subjects With Coronary Artery Disease.

OBJECTIVE: Pepducins are membrane-tethered, cell-penetrating lipopeptides that target the cytoplasmic surface of their cognate receptor. Here, we report the first human use of a protease-activated receptor-1-based pepducin, which is intended as an antiplatelet agent to prevent ischemic complications of percutaneous coronary interventions. APPROACH AND RESULTS: PZ-128 was administered by 1 to 2 hours continuous intravenous infusion (0.01-2 mg/kg) to 31 subjects with coronary artery disease or multiple coronary artery disease risk factors. Safety, antiplatelet efficacy, and pharmacokinetics were assessed at baseline and 0.5, 1, 2, 6, 24 hours, and 7 to 10 days postdosing. The inhibitory effects of PZ-128 on platelet aggregation stimulated by the protease-activated receptor-1 agonist SFLLRN (8 µmol/L) at 30 minutes to 6 hours were dose dependent with 20% to 40% inhibition at 0.3 mg/kg, 40% to 60% at 0.5 mg/kg, and ≥ 80% to 100% at 1 to 2 mg/kg. The subgroup receiving aspirin in the 0.5 and 1-mg/kg dose cohorts had 65% to 100% inhibition of final aggregation to SFLLRN at 30 minutes to 2 hours and 95% to 100% inhibition by 6 hours. The inhibitory effects of 0.5 mg/kg PZ-128 were reversible with 50% recovery of aggregation to SFLLRN by 24 hours. There were no significant effects of PZ-128 on aggregation induced by AYPGKF, ADP, or collagen, indicating that the observed effects were specific to protease-activated receptor-1. The plasma half-life was 1.3 to 1.8 hours, and PZ-128 was nondetectable in urine. There were no effects on bleeding, coagulation, clinical chemistry, or ECG parameters. CONCLUSIONS: PZ-128 is a promising antiplatelet agent that provides rapid, specific, dose dependent, and reversible inhibition of platelet protease-activated receptor-1 through a novel intracellular mechanism. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01806077.

Central aortic pulse pressure, thrombogenicity and cardiovascular risk.

High central aortic pulse pressure (CPP) and thrombin-induced platelet-fibrin clot strength (TIP-FCS) have been associated with ischemic outcomes in patients with coronary artery disease in separate studies. But, the ischemic risk associated with these factors has never been analyzed in a single study and their interrelation is unknown. The primary aim of the study was to establish cut points for CPP and TIP-FCS measured at the time of catheterization associated with long term major adverse cardiovascular events. We enrolled 334 consecutive patients undergoing cardiac catheterization and assessed thrombogenicity by thrombelastography. Patients were followed up to 3 years. The primary endpoint was a composite of cardiovascular death, myocardial infarction, and ischemic stroke and the secondary endpoint was occurrence of the primary endpoint or recurrent ischemic events requiring hospitalization. Patients with primary and secondary endpoint occurrence had higher CPP (83 ± 20 vs. 60 ± 18 mmHg, p < 0.0001; 70 ± 21 vs. 59 ± 18 mmHg, p < 0.0001, respectively) and TIP-FCS (68.5 ± 5.8 vs. 65.5 ± 5.0 mm, p = 0.008; 67.4 ± 5.9 vs. 65.2 ± 4.8 mm, p = 0.001, respectively). CPP >60 mmHg and TIP-FCS >69 mm were both independent predictors of primary endpoint occurrence (p = 0.0001 and p = 0.02, respectively). ROC analysis for CPP and TIP-FCS showed a C-statistic of 0.81 (p < 0.0001) and 0.68 (p = 0.007) for the primary endpoint, respectively. Patients with CPP >60 mmHg had higher TIP-FCS (66.8 ± 5.1 vs. 64.8 ± 5.0 mm, p < 0.001) and primary and secondary endpoint occurrence (13 vs. 1.1%, p < 0.0001 and 31.8 vs. 14.4%, p = 0.0002, respectively). CPP >60 mmHg + TIP-FCS > 69 mm was associated with a markedly increased risk of primary endpoint occurrence [HR (95% CI) 5.4(2.3-12.5), p = 0.0001]. High CPP and thrombogenicity are interrelated; each are independently associated with increased cardiovascular risk; and simultaneous presence markedly enhances risk. The mechanistic link between CPP and thrombogenicity deserves further study.