Stable Atherosclerotic Disease Research Articles

CE1 - Cost-Effectiveness of Rivaroxaban and Aspirin Compared to Aspirin Alone in Patients with Stable Cardiovascular Disease: An Australian Perspective

Abstract Objective In light of the Cardiovascular Outcomes for People using Anticoagulation Strategies (COMPASS) trial, our objective was to assess the cost-effectiveness, from the Australian healthcare perspective, of rivaroxaban in combination with aspirin versus aspirin alone for the prevention of recurrent cardiovascular disease among patients with stable atherosclerotic vascular disease. Methods A Markov model was developed using input data from the COMPASS trial to predict the clinical course and costs of patients over a 20-year time-horizon. The model comprised of three health states: ‘Alive without recurrent CVD’, ‘Alive after recurrent CVD’ and ‘Dead’. Costs were from the Australian public healthcare system perspective, and estimated from published sources, as were utility data. The costs of rivaroxaban were based on current acquisition prices on the Australian Pharmaceutical Benefits Schedule (PBS) and assumed as AUD$3.09/day. The main outcome of interest was the incremental cost-effectiveness ratio (ICER) in terms of cost per quality adjusted life year (QALY) gained, and cost per year of life saved (YoLS). Costs and benefits were discounted by 5.0% per year. Results Compared to aspirin alone, rivaroxaban plus aspirin was estimated to cost an additional AUD$12,156 (discounted) per person, but lead to 0.516 YoLS (discounted) and 0.386 QALYs gained (discounted), over 20 years. These equated to ICERs of AUD$23,560/YoLS and AUD$31,436/QALY gained. We have assumed a threshold of AUD$50,000/QALY gained to signify cost-effectiveness. Conclusion Compared to aspirin, rivaroxaban in combination with aspirin is likely to be cost-effective in preventing recurrent cardiovascular events in patients with stable atherosclerotic vascular disease.

Clinical Benefit of Evolocumab by Severity and Extent of Coronary Artery Disease: Analysis From FOURIER.

The FOURIER trial (Further Cardiovascular Outcomes Research With PCSK9 Inhibition in Patients With Elevated Risk) recently showed that the PCSK9 (proprotein convertase subtilisin-kexin type 9) inhibitor evolocumab significantly reduced major vascular events in patients with stable atherosclerotic cardiovascular disease, including patients with prior myocardial infarction (MI). Within the broad group of patients with prior MI, we hypothesized that readily ascertainable features would identify subsets who derive greater clinical risk reduction with evolocumab. The 22 351 patients with a prior MI were characterized on the basis of time from most recent MI, number of prior MIs, and presence of residual multivessel coronary artery disease (≥40% stenosis in ≥2 large vessels). The relative and absolute risk reductions in major vascular events, including the primary end point (cardiovascular death, MI, stroke, hospitalization for unstable angina, or coronary revascularization) and the key secondary end point (cardiovascular death, MI, or stroke), with evolocumab in these subgroups were compared. A total of 8402 patients (38%) were within 2 years of their most recent MI; 5285 patients (24%) had ≥2 prior MIs; and 5618 patients (25%) had residual multivessel coronary artery disease. In a multivariable-adjusted model that simultaneously included all 3 high-risk features and other baseline covariates, more recent MI, multiple prior MIs, and residual multivessel coronary disease remained independent predictors of cardiovascular outcomes, with adjusted hazard ratios (HRs) for the primary end point of 1.37 (95% confidence interval [CI],1.22-1.53), 1.78 (95% CI, 1.59-1.99), and 1.39 (95% CI, 1.24-1.56; all P<0.001). The relative risk reductions with evolocumab for the primary end point tended to be greater in the high-risk subgroups and were 20% (HR, 0.80; 95% CI, 0.71-0.91), 18% (HR, 0.82; 95% CI, 0.72-0.93), and 21% (HR, 0.79; 95% CI, 0.69-0.91) for those with more recent MI, multiple prior MIs, and residual multivessel coronary artery disease, whereas they were 5% (HR, 0.95; 95% CI, 0.85-1.05), 8% (HR, 0.92; 95% CI, 0.84-1.02), and 7% (HR, 0.93; 95% CI, 0.85-1.02) in those without, respectively. Given the higher baseline risk, the respective absolute risk reductions at 3 years exceeded 3% in the high-risk groups (3.4%, 3.7%, and 3.6%) versus ≈1% in the low-risk groups (0.8%, 1.3%, and 1.2%). Patients closer to their most recent MI, with multiple prior MIs, or with residual multivessel coronary artery disease are at high risk for major vascular events and experience substantial risk reductions with low-density lipoprotein cholesterol lowering with evolocumab. URL: https://www.clinicaltrials.gov . Unique identifier: NCT01764633.

Antithrombotic drugs in cardiovascular medicine: a year in review.

To provide an up to date review of the most recent randomized clinical trials in the field of antithrombotic drugs for cardiovascular diseases. In 2017, low-dose anti-Xa treatment added to aspirin proved to be more efficacious than either treatment alone in patients with stable atherosclerotic disease despite the increase in nonfatal bleeding events. Furthermore, anticoagulation strategy during coronary interventions was again tested in a registry-based trial and showed comparable efficacy and safety between heparin alone and bivalirudin. Data from safety trials demonstrated lower risk of bleeding with dual antithrombotic therapy compared with triple antithrombotic therapy following coronary intervention, albeit these trials were underpowered for efficacy. Although still in its infancy, the role of antithrombotic treatment following transcatheter aortic valve replacement (TAVR) has been investigated in small trials with evidence that a single antiplatelet drug may be noninferior to dual antiplatelet therapy with a better safety profile. In this review, we discuss the most recent clinical trials investigating antithrombotic drugs for cardiovascular diseases published in 2017.

Cost-effectiveness of rivaroxaban and aspirin compared to aspirin alone in patients with stable cardiovascular disease: An Australian perspective

ObjectiveIn light of the Cardiovascular Outcomes for People using Anticoagulation Strategies (COMPASS) trial, our objective was to assess the cost-effectiveness, from the Australian healthcare perspective, of rivaroxaban in combination with aspirin versus aspirin alone for the prevention of recurrent cardiovascular disease among patients with stable atherosclerotic vascular disease. MethodsA Markov model was developed using input data from the COMPASS trial to predict the clinical course and costs of patients over a 20-year time-horizon. The model comprised of three health states: ‘Alive without recurrent CVD’, ‘Alive after recurrent CVD’ and ‘Dead’. Costs were from the Australian public healthcare system perspective, and estimated from published sources, as were utility data. The costs of rivaroxaban were based on current acquisition prices on the Australian Pharmaceutical Benefits Schedule (PBS) and assumed as AUD$3.09/day. The main outcome of interest was the incremental cost-effectiveness ratio (ICER) in terms of cost per quality adjusted life year (QALY) gained, and cost per year of life saved (YoLS). Costs and benefits were discounted by 5.0% per year. ResultsCompared to aspirin alone, rivaroxaban plus aspirin was estimated to cost an additional AUD$12,156 (discounted) per person, but lead to 0.516 YoLS (discounted) and 0.386 QALYs gained (discounted), over 20 years. These equated to ICERs of AUD$23,560/YoLS and AUD$31,436/QALY gained. We have assumed a threshold of AUD$50,000/QALY gained to signify cost-effectiveness. ConclusionCompared to aspirin, rivaroxaban in combination with aspirin is likely to be cost-effective in preventing recurrent cardiovascular events in patients with stable atherosclerotic vascular disease.

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.

Inflammatory and Cholesterol Risk in the FOURIER Trial.

In the FOURIER trial (Further Cardiovascular Outcomes Research With PCSK9 Inhibition in Patients With Elevated Risk), the PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitor evolocumab reduced low-density lipoprotein cholesterol (LDL-C) and cardiovascular risk. It is not known whether the efficacy of evolocumab is modified by baseline inflammatory risk. We explored the efficacy of evolocumab stratified by baseline high-sensitivity C-reactive protein (hsCRP). We also assessed the importance of inflammatory and residual cholesterol risk across the range of on-treatment LDL-C concentrations. Patients (n=27 564) with stable atherosclerotic cardiovascular disease and LDL-C ≥70 mg/dL on a statin were randomly assigned to evolocumab versus placebo and followed for a median of 2.2 years (1.8-2.5). The effects of evolocumab on the primary end point of cardiovascular death, myocardial infarction, stroke, hospitalization for unstable angina or coronary revascularization, and the key secondary end point of cardiovascular death, myocardial infarction, or stroke were compared across strata of baseline hsCRP (<1, 1-3, and >3 mg/dL). Outcomes were also assessed across values for baseline hsCRP and 1-month LDL-C in the entire trial population. Multivariable models adjusted for variables associated with hsCRP and 1-month LDL-C were evaluated. A total of 7981 (29%) patients had a baseline hsCRP<1 mg/L, 11 177 (41%) had a hsCRP 1 to 3 mg/L, and 8337 (30%) had a hsCRP >3 mg/L. Median (interquartile range) baseline hsCRP was 1.8 (0.9-3.6) mg/L and levels were not altered by evolocumab (change at 48 weeks of -0.2 mg/dL [-1.0 to 0.4] in both treatment arms). In the placebo arm, patients in higher baseline hsCRP categories experienced significantly higher 3-year Kaplan-Meier rates of the primary and key secondary end points: 12.0%, 13.7%, and 18.1% for the primary end point (Ptrend<0.0001) and 7.4%, 9.1%, and 13.2% for the key secondary end point (Ptrend<0.0001) for categories of <1, 1 to 3, and >3 mg/dL, respectively. The relative risk reductions for the primary end point and key secondary end point with evolocumab were consistent across hsCRP strata (P-interactions>0.15 for both). In contrast, the absolute risk reductions with evolocumab tended to be greater in patients with higher hsCRP: 1.6%, 1.8%, and 2.6% and 0.8%, 2.0%, and 3.0%, respectively, for the primary and key secondary end points across hsCRP strata. In adjusted analyses of the association between LDL-C and hsCRP levels and cardiovascular risk, both LDL-C and hsCRP were independently associated with the primary outcome (P<0.0001 for each). LDL-C reduction with evolocumab reduces cardiovascular events across hsCRP strata with greater absolute risk reductions in patients with higher-baseline hsCRP. Event rates were lowest in patients with the lowest hsCRP and LDL-C. URL: https://www.clinicaltrials.gov. Unique identifier: NCT01764633.

Rationale and design for the Vascular Outcomes study of ASA along with rivaroxaban in endovascular or surgical limb revascularization for peripheral artery disease (VOYAGER PAD)

BackgroundPatients with peripheral artery disease (PAD) undergoing a lower-extremity revascularization are at heightened risk for ischemic cardiac and limb events. Although intensification of antithrombotic therapy after revascularization has demonstrated benefit in coronary disease populations, this approach has not been well studied or shown consistent benefit in PAD. Recent trial evidence demonstrated that a treatment strategy of rivaroxaban added to background antiplatelet therapy reduced ischemic risk in patients following recent acute coronary syndromes, as well as in patients with stable atherosclerotic vascular disease. Whether these benefits extend to the population of patients with symptomatic lower-extremity PAD undergoing revascularization is the objective of the VOYAGER PAD trial. Study designVOYAGER PAD is an international randomized, double-blind, placebo-controlled trial to evaluate the efficacy and safety of rivaroxaban in symptomatic PAD patients undergoing a peripheral surgical and/or endovascular revascularization. Patients are randomized in a 1:1 ratio to either rivaroxaban 2.5 mg twice daily or placebo, on a background of low-dose aspirin (100 mg daily). In addition, the use of a limited course of P2Y12 inhibition is allowed at the discretion of the site investigator. The primary efficacy end point is a novel composite of myocardial infarction, ischemic stroke, cardiovascular death, acute limb ischemia, and major amputation of vascular etiology. The primary safety end point is major bleeding according to the Thrombolysis in Myocardial Infarction definition. Enrolment began in August 2015 and will complete randomization of at least 6,500 patients by January 2018. This event-driven trial is expected to observe outcomes over a mean patient follow-up of 30 months. ConclusionsVOYAGER PAD is evaluating the efficacy of rivaroxaban added to background antiplatelet therapy to reduce major cardiovascular and limb ischemic vascular outcomes in the high-risk population of PAD patients undergoing peripheral revascularization.

Rivaroxaban with or without Aspirin in Stable Cardiovascular Disease

BackgroundWe evaluated whether rivaroxaban alone or in combination with aspirin would be more effective than aspirin alone for secondary cardiovascular prevention.MethodsIn this double-blind trial, we randomly assigned 27,395 participants with stable atherosclerotic vascular disease to receive rivaroxaban (2.5 mg twice daily) plus aspirin (100 mg once daily), rivaroxaban (5 mg twice daily), or aspirin (100 mg once daily). The primary outcome was a composite of cardiovascular death, stroke, or myocardial infarction. The study was stopped for superiority of the rivaroxaban-plus-aspirin group after a mean follow-up of 23 months.ResultsThe primary outcome occurred in fewer patients in the rivaroxaban-plus-aspirin group than in the aspirin-alone group (379 patients [4.1%] vs. 496 patients [5.4%]; hazard ratio, 0.76; 95% confidence interval [CI], 0.66 to 0.86; P<0.001; z=−4.126), but major bleeding events occurred in more patients in the rivaroxaban-plus-aspirin group (288 patients [3.1%] vs. 170 patients [1.9%]; hazard ratio, 1.70; 95% CI, 1.40 to 2.05; P<0.001). There was no significant difference in intracranial or fatal bleeding between these two groups. There were 313 deaths (3.4%) in the rivaroxaban-plus-aspirin group as compared with 378 (4.1%) in the aspirin-alone group (hazard ratio, 0.82; 95% CI, 0.71 to 0.96; P=0.01; threshold P value for significance, 0.0025). The primary outcome did not occur in significantly fewer patients in the rivaroxaban-alone group than in the aspirin-alone group, but major bleeding events occurred in more patients in the rivaroxaban-alone group.ConclusionsAmong patients with stable atherosclerotic vascular disease, those assigned to rivaroxaban (2.5 mg twice daily) plus aspirin had better cardiovascular outcomes and more major bleeding events than those assigned to aspirin alone. Rivaroxaban (5 mg twice daily) alone did not result in better cardiovascular outcomes than aspirin alone and resulted in more major bleeding events. (Funded by Bayer; COMPASS ClinicalTrials.gov number, NCT01776424.)

High-Sensitivity Troponin I in Stable Patients with Atherosclerotic Disease in the TRA 2°P - TIMI 50 Trial.

Cardiac troponin I, measured with a high-sensitivity assay (hs-TnI), is well-established for risk prediction in acute coronary syndromes. However, its prognostic role in stable atherosclerotic disease, particularly for future myocardial infarction (MI), is less well defined. We measured hs-TnI (Abbott ARCHITECT) in 15833 patients with prior MI, ischemic stroke, or peripheral arterial disease from the placebo-controlled Thrombin Receptor Antagonist in Secondary Prevention of Atherothrombotic Ischemic Events (TRA 2°P)-Thrombolysis in Myocardial Infarction (TIMI) 50 trial of the platelet inhibitor vorapaxar, excluding patients with recent MI (<30 days). hs-TnI was categorized into 5 groups based on the detection limit (1.9 ng/L), 99th percentile reference limit (26 ng/L), and tertiles in between (1.9-26 ng/L), as well as sex-specific reference limits. Higher hs-TnI concentration was associated with older age, male sex, and increased atherosclerosis burden. hs-TnI identified a graded 3-year risk of cardiovascular death, MI, or stroke from 5.0% to 18.6% (P < 0.001), driven by cardiovascular death and MI (P < 0.001). This risk was independent of established clinical risk indicators, B-type natriuretic peptide and C-reactive protein [adjusted hazard ratio 2.70 (95% CI, 1.96-3.71), P < 0.001 for hs-TnI >26 ng/L vs <1.9 ng/L]. In patients with prior MI, there was a pattern of greater absolute benefit with vorapaxar in patients with an increased hs-TnI (absolute risk difference 1.9% with hs-TnI >26 ng/L vs 0.3% with hs-TnI <1.9 ng/L; P interaction = 0.82). In stable patients with established atherosclerosis, hs-TnI concentrations effectively stratified the risk of new or recurrent cardiovascular (CV) events, in particular CV death and MI. High-risk patients with prior MI identified by increased hs-TnI had a substantial absolute improvement in net clinical outcome with vorapaxar.

Pharmacological approaches of refractory angina.

Refractory angina refers to a group of patients with stable coronary atherosclerotic disease and angina symptoms, unresponsive to traditional medical management, while considered to be suboptimal candidates for revascularization procedures. Up to 15% of angina patients are considered to have refractory angina and, taking into account the aging population and the improvements in the treatment of stable coronary artery disease, the incidence of this entity is expected to increase. This review describes traditional and novel pharmacotherapies for symptoms relief and for long-term management of refractory angina. Mechanisms of action and relevant clinical trials are discussed and current recommendations from major European and US cardiovascular societies are reported.

Abstract 18549: High-sensitivity Troponin I in Stable Patients With Atherosclerotic Disease in the TRA2°P- TIMI 50 Trial

Background: Cardiac troponin I, measured with a high-sensitivity assay (hsTnI), is a well-established prognosticator in patients with acute coronary syndromes. However, its prognostic role in patients with stable atherosclerotic disease, particularly with respect to new or recurrent myocardial infarction (MI), is less defined. Methods: We measured hsTnI (Abbott ARCHITECT) in 19,429 patients with prior MI, ischemic stroke, or symptomatic peripheral arterial disease, who had available baseline samples in the TRA 2°P-TIMI 50 trial of the platelet inhibitor vorapaxar vs. placebo. hsTnI concentration was categorized into 5 groups based on the detection limit (1.9 ng/L), the 99th percentile reference limit (26 ng/L), and tertiles in between (1.9-26 ng/L). The median follow-up was 2.5 years. Sensitivity analyses excluded patients with a history of MI in the prior 30 days and tested sex-specific cutpoints. Results: Higher baseline hsTnI levels were associated with older age, male sex, and an increased burden of atherosclerotic disease. hsTnI identified a graded risk of cardiovascular (CV) death, MI, or stroke with a consistent pattern across each element of this composite, in particular CV death and MI (Figure). This risk relationship was independent of established clinical risk indicators, B-type natriuretic peptide and C-reactive protein (adj-HR 2.17, 95% CI 1.61-2.92 for hsTnI &gt;26 ng/L) and was consistent after excluding pts with recent MI (adj-HR 2.69, 95% CI 1.95-3.71 for hsTnI &gt;26 ng/L). There were no meaningful differences using sex-specific hsTnI cutpoints. The interaction with efficacy of vorapaxar vs. placebo according to hsTnI will be presented. Conclusion: When measured in stable patients with established atherosclerosis, hsTnI concentrations, even below the 99th percentile reference limit, effectively stratified the risk of new or recurrent MI.

Adjunctive therapies to reduce thrombotic events in patients with a history of myocardial infarction: role of vorapaxar.

Acute myocardial infarction (AMI) is generally attributed to coronary atherothrombotic disease. Platelet activation is essential for thrombus formation and is thus an important target for pharmacological intervention to prevent and treat AMI. Despite contemporary treatment with dual antiplatelet therapy, including acetylsalicylic acid and adenosine diphosphate receptor antagonists, patients with prior AMI remain at increased risk of future thrombotic events. This has stimulated the search for more potent antithrombotic agents. Among these is the oral protease-activated receptor-1 antagonist vorapaxar, which represents a new oral antiplatelet agent to reduce thrombotic risk in patients with atherothrombotic disease. The TRACER and the TRA 2°P-TIMI 50 trials concluded that vorapaxar in addition to standard therapy reduced ischemic adverse cardiac events. A remarkable benefit was observed in patients with stable atherosclerotic disease, particularly those with a previous history of AMI. Although favorable effects were seen in reduction of adverse cardiac events, this was associated with excess major and intracranial bleeding, particularly in patients at high risk of bleeding and those with a history of stroke or transient ischemic attack. Currently, the lack of a reliable individualized risk stratification tool to assess patients for thrombotic and bleeding tendencies in order to identify those who might gain most net clinical benefit has led to limited use of vorapaxar in clinical practice. Vorapaxar may find a niche as an adjunct to standard care in patients at high risk of thrombotic events and who are at low risk of bleeding.

Monocyte subset distribution in patients with stable atherosclerosis and elevated levels of lipoprotein(a)

BackgroundLipoprotein(a) (Lp(a)) is a proatherogenic plasma lipoprotein currently established as an independent risk factor for the development of atherosclerotic disease and as a predictor for acute thrombotic complications. In addition, Lp(a) is the major carrier of proinflammatory oxidized phospholipids (OxPL). Today, atherosclerosis is considered to be an inflammatory disease of the vessel wall in which monocytes and monocyte-derived macrophages are crucially involved. Circulating monocytes can be divided according to their surface expression pattern of CD14 and CD16 into at least 3 subsets with distinct inflammatory and atherogenic potential.ObjectiveThe aim of this study was to examine whether elevated levels of Lp(a) and OxPL on apolipoprotein B-100–containing lipoproteins (OxPL/apoB) are associated with changes in monocyte subset distribution.MethodsWe included 90 patients with stable coronary artery disease. Lp(a) and OxPL/apoB were measured, and monocyte subsets were identified as classical monocytes (CMs; CD14++CD16−), intermediate monocytes (IMs; CD14++CD16+), and nonclassical monocytes (NCMs; CD14+CD16++) by flow cytometry.ResultsIn patients with elevated levels of Lp(a) (>50 mg/dL), monocyte subset distribution was skewed toward an increase in the proportion of IM (7.0 ± 3.8% vs 5.2 ± 3.0%; P = .026), whereas CM (82.6 ± 6.5% vs 82.0 ± 6.8%; P = .73) and NCM (10.5 ± 5.3 vs 12.8 ± 6.0; P = .10) were not significantly different. This association was independent of clinical risk factors, choice of statin treatment regime, and inflammatory markers. In addition, OxPL/apoB was higher in patients with elevated Lp(a) and correlated with IM but not CM and NCM.ConclusionsIn conclusion, we provide a potential link between elevated levels of Lp(a) and a proatherogenic distribution of monocyte subtypes in patients with stable atherosclerotic disease.

PAR1 antagonists inhibit thrombin-induced platelet activation whilst leaving the PAR4-mediated response intact

Thrombin-induced platelet activation is initiated by PAR1 and PAR4 receptors. Vorapaxar, a PAR1 antagonist, has been assessed in patients with acute coronary syndromes (ACS) and stable atherosclerotic disease in addition to standard-of-care treatment. In clinical trials, vorapaxar has been observed to reduce the frequency of ischaemic events in some subgroups though in others has increased the frequency of bleeding events. Among patients undergoing CABG surgery, which is associated with excess thrombin generation, bleeding was not increased. The aim of these studies was to investigate the effects of selective PAR1 antagonism on thrombin-induced platelet activation in patients receiving vorapaxar or placebo in the TRACER trial and to explore the roles of PAR1 and PAR4 in thrombin-induced platelet activation in healthy volunteers. ACS patients receiving vorapaxar or placebo in the TRACER trial were studied at baseline and 4 hours, 1 and 4 months during drug administration. Thrombin-induced calcium mobilisation in platelet-rich plasma was assessed by flow cytometry. In vitro studies were performed in healthy volunteers using the PAR1 antagonist SCH79797 or PAR4 receptor desensitisation. Vorapaxar treatment significantly inhibited thrombin-induced calcium mobilisation, leaving a residual, delayed response. These findings were consistent with calcium mobilisation mediated via the PAR4 receptor and were reproduced in vitro using SCH79797. PAR4 receptor desensitization, in combination with SCH79797, completely inhibited thrombin-induced calcium mobilisation confirming that the residual calcium mobilisation was mediated via PAR4. In conclusion vorapaxar selectively antagonises the PAR1-mediated component of thrombin-induced platelet activation, leaving the PAR4-mediated response intact, which may explain why vorapaxar is well tolerated in patients undergoing CABG surgery since higher thrombin levels in this setting may override the effects of PAR1 antagonism through PAR4 activation, thus preserving haemostasis. Further assessment may be warranted.

Chapter Five - Pregnancy-Associated Plasma Protein A (PAPP-A) and Preeclampsia

Pregnancy-associated plasma protein A (PAPP-A) is a key regulator of insulin-like growth factor bioavailability essential for normal fetal development. In maternal blood, this protein increases with gestational age and then rapidly decreases after delivery. It is routinely used for Down syndrome screening in the first trimester of pregnancy, and its decrease compared to a normal pregnancy indicates an increased risk for both chromosomal anomalies and adverse pregnancy outcomes. It belongs to a group of biomarkers that predict later preeclampsia development, primarily early onset preeclampsia; however, it should be combined with a Doppler ultrasonography of the uterine artery (pulsatile index) and other biochemical and maternal factors to achieve a higher detection rate with an acceptable false positivity rate. Some studies have demonstrated an even more pronounced decrease of PAPP-A in the early second trimester of pregnancy in women who subsequently develop preeclampsia compared with women who do not develop preeclampsia. Conversely, during the last trimester of pregnancy, its concentration increases even more in patients with preeclampsia than in patients without. It is also detectable at very low levels in nonpregnant individuals, and a higher concentration indicates an adverse effect in patients with acute coronary syndromes or stable atherosclerotic disease and in patients with end-stage renal disease who are being treated with hemodialysis.

Localization of Microfibrillar-Associated Protein 4 (MFAP4) in Human Tissues: Clinical Evaluation of Serum MFAP4 and Its Association with Various Cardiovascular Conditions

Microfibrillar-associated protein 4 (MFAP4) is located in the extracellular matrix (ECM). We sought to identify tissues with high levels of MFAP4 mRNA and MFAP4 protein expression. Moreover, we aimed to evaluate the significance of MFAP4 as a marker of cardiovascular disease (CVD) and to correlate MFAP4 with other known ECM markers, such as fibulin-1, osteoprotegerin (OPG), and osteopontin (OPN). Quantitative real-time PCR demonstrated that MFAP4 mRNA was more highly expressed in the heart, lung, and intestine than in other elastic tissues. Immunohistochemical studies demonstrated high levels of MFAP4 protein mainly at sites rich in elastic fibers and within blood vessels in all tissues investigated. The AlphaLISA technique was used to determine serum MFAP4 levels in a clinical cohort of 172 patients consisting of 5 matched groups with varying degrees of CVD: 1: patients with ST elevation myocardial infarction (STEMI), 2: patients with non-STEMI, 3: patients destined for vascular surgery because of various atherosclerotic diseases (stable atherosclerotic disease), 4: apparently healthy individuals with documented coronary artery calcification (CAC-positive), and 5: apparently healthy individuals without signs of coronary artery calcification (CAC-negative). Serum MFAP4 levels were significantly lower in patients with stable atherosclerotic disease than CAC-negative individuals (p<0.05). Furthermore, lower serum MFAP4 levels were present in patients with stable atherosclerotic disease compared with STEMI and non-STEMI patients (p<0.05). In patients with stable atherosclerotic disease, positive correlations between MFAP4 and both fibulin-1 (ρ = 0.50; p = 0.0244) and OPG (ρ = 0.62; p = 0.0014) were found. Together, these results indicate that MFAP4 is mainly located in elastic fibers and is highly expressed in blood vessels. The present study suggests that serum MFAP4 varies in groups of patients with different cardiovascular conditions. Further studies are warranted to describe the role of serum MFAP4 as a biomarker of stable atherosclerotic disease.

Abstract 18069: Evaluation of Potential Antiplatelet Effects of CSL112, a Novel Formulation of Human Apolipoprotein A-I: Results From a Phase 2a Study

Background: CSL112, a novel formulation of apoA-I purified from human plasma and reconstituted to form HDL particles, is in development for the treatment of patients with coronary artery disease. Prior data with a similar compound (CSL111) indicated a potential short-term platelet inhibitory effect. We assessed the potential antiplatelet effects of CSL112 in a phase 2a multicenter, randomized, ascending dose study in subjects with stable atherosclerotic disease. Methods: Subjects (n=44) on aspirin (75-325 mg/day) and clopidogrel (75 mg/day, n=37) or prasugrel (10 mg/day, n=7) for &gt;30 days in addition to standard of care therapy were randomized to a single dose of placebo or CSL112: 1.7, 3.4, and 6.8g. Conventional platelet aggregation in response to 2 mM arachidonic acid (AA), 5 and 10 μM adenosine diphosphate (ADP), and 4μg/mL collagen were performed at baseline and 8, 12, 24 and 48 h post-dosing. The change from baseline in maximal aggregation was determined and compared by ANOVA analysis among the treatments at any time point. Results: Baseline characteristics were well balanced across treatment groups. Compared to placebo, CSL112 did not show any time or dose dependent effects on maximum platelet aggregation in response to any agonist (p&gt;0.05 for all tests) [Table]. Conclusion: CSL112, when co-administered with dual antiplatelet therapy, does not significantly influence platelet aggregation in response to AA, ADP and collagen. Based on these data, it is anticipated that CSL112 will not affect hemostasis when administered with concomitant antiplatelet therapies.

THU0047 Carotid plaque characteristics are associated with disease activity in rheumatoid arthritis

BackgroundCarotid plaques (CP) in rheumatoid arthritis (RA) are predictive of acute coronary syndrome in RA patients, suggesting that atherosclerotic plaques in RA are vulnerable.(1)ObjectivesTo characterize vulnerability of CP in RA...

Vorapaxar in Patients With Peripheral Artery Disease

Background— Vorapaxar is a novel antagonist of protease-activated receptor-1, the primary receptor for thrombin on human platelets that is also present on vascular endothelium and smooth muscle. Patients with peripheral artery disease are at risk of systemic atherothrombotic events, as well as acute and chronic limb ischemia and the need for peripheral revascularization. Methods and Results— The Trial to Assess the Effects of SCH 530348 in Preventing Heart Attack and Stroke in Patients With Atherosclerosis (TRA2°P-TIMI 50) was a randomized, double-blind, placebo-controlled trial of vorapaxar in 26 449 patients with stable atherosclerotic vascular disease (myocardial infarction, stroke, or peripheral artery disease). Patients with qualifying peripheral artery disease (n=3787) had a history of claudication and an ankle-brachial index of &lt;0.85 or prior revascularization for limb ischemia. The primary efficacy end point was cardiovascular death, myocardial infarction, or stroke, and the principal safety end point was Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO) bleeding. In the peripheral artery disease cohort, the primary end point did not differ significantly with vorapaxar (11.3% versus 11.9%; hazard ratio, 0.94; 95% confidence interval, 0.78–1.14; P =0.53). However, rates of hospitalization for acute limb ischemia (2.3% versus 3.9%; hazard ratio, 0.58; 95% confidence interval, 0.39–0.86; P =0.006) and peripheral artery revascularization (18.4% versus 22.2%; hazard ratio, 0.84; 95% confidence interval, 0.73–0.97; P =0.017) were significantly lower in patients randomized to vorapaxar. Bleeding occurred more frequently with vorapaxar compared with placebo (7.4% versus 4.5%; hazard ratio, 1.62; 95% confidence interval, 1.21–2.18; P =0.001). Conclusions— Vorapaxar did not reduce the risk of cardiovascular death, myocardial infarction, or stroke in patients with peripheral artery disease; however, vorapaxar significantly reduced acute limb ischemia and peripheral revascularization. The beneficial effects of protease-activated receptor-1 antagonism on limb vascular events were accompanied by an increased risk of bleeding. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00526474.

The study on the relationship between the change of ST-T of chronic stable CAD and LVEF

Objective To study the relationship between the change of resting electrocardiogram ST-T in chronic stable coronary atherosclerotic heart disease(CAD) and left ventricle enjection fraction(LVEF).To know the significance that the change of ST-T may predict the function of left ventricle.Methods 80 patients with CAD in our c ardaic department were analyzed retrospectively,40 patients with the change of ST-T (positive group) and 40 patients without the change of ST-T(negative group) were analyzed the outcome of LVEF and the extent of coronary lesion.Results The LVEF of positive group was lower than negative group obviously,the comparision between both groups had statistical significance (t =6.125,P =0.000).In the electrocardiogram positive group,the number of the patients who had 2 and more than 2 branches lesion was more than negative group,the comparision between both groups had statistical significance(x2 =9.683,P =0.008).Conclusion The change of ST-T may predict the function of left ventricle of patients with chronic stable coronary atherosclerotic heart disease,the relationship may be connected with the degree of coronary lesion. Key words: Coronary disease; Body surface potential mapping; Stroke volume