Changes in circulating ApoJ-Glyc levels in patients with suspected acute coronary syndrome: The EDICA trial

BACKGROUND

Myocardial ischemia induces intracellular accumulation of non-glycosylated apolipoprotein J that results in a reduction of circulating glycosylated ApoJ (ApoJ-Glyc). The latter has been suggested to be a marker of transient myocardial ischemia.

OBJECTIVE

This proof-of-concept clinical study aimed to assess whether changes in circulating ApoJ-Glyc could detect myocardial ischemia in patients attending the emergency department (ED) with chest pain suggestive of acute coronary syndrome (ACS).

METHODS

In suspected ACS patients, EDICA (Early Detection of Myocardial Ischemia in Suspected Acute Coronary Syndromes by ApoJ-Glyc a Novel Pathologically based Ischemia Biomarker), a multicentre, international, cohort study assessed changes in 2 glycosylated variants of ApoJ-Glyc, (ApoJ-GlycA2 and ApoJ-GlycA6), in serum samples obtained at ED admission (0 h), and 1 h and 3 h thereafter, blinded to the clinical diagnosis (i.e. STEMI, NSTEMI, unstable angina, non-ischemic).

RESULTS

404 patients were recruited; 291 were given a clinical diagnosis of "non-ischemic" chest pain and 113 were considered to have had an ischemic event. ApoJ-GlycA6 was lower on admission in ischemic compared with "non-ischemic" patients (66 [46-90] vs. 73 [56-95] μg/ml; P = 0.04). 74% of unstable angina patients (all with undetectable hs-Tn), had ischemic changes in ApoJ-Glyc at 0 h and 89% at 1 h. Initially low ApoJ-Glyc levels in 62 patients requiring coronary revascularization increased significantly after successful percutaneous intervention.

CONCLUSIONS

Circulating ApoJ-Glyc concentrations decrease early in ED patients with myocardial ischemia compared with "non-ischemic" patients, even in the absence of troponin elevations. ApoJ-Glyc may be a useful marker of myocardial ischemia in the ED setting.

Lipoprotein(a), cardiovascular events, and benefit of P2Y12 inhibition: insights from the PEGASUS-TIMI 54 trial

Background

Lp(a) plays a causal role in atherogenesis and may exert pro-thrombotic effects by inhibiting fibrinolysis owing to its structural homology with plasminogen. Patients with higher Lp(a) concentrations may derive greater benefit from anti-thrombotic therapy.

Purpose

We assessed whether patients with higher Lp(a) derive greater risk reduction from P2Y12 inhibition with ticagrelor vs. placebo on a background of aspirin therapy.

Methods

Lp(a) concentration was measured (Randox) in a prospective nested cohort of 8,967 pts enrolled in PEGASUS-TIMI 54, a randomized trial of ticagrelor vs. placebo in patients 1–3 years post MI (median follow-up: 2.7 y). Lp(a) was dichotomized at 200 nmol/L as an established threshold of risk. The prespecified MACE endpoint was CV death, MI or stroke, with KM rates reported at 3y. Cox proportional hazards were used to assess the relationship between Lp(a), MACE and treatment benefit. Models were adjusted for relevant baseline characteristics including apolipoprotein B.

Results

The median Lp(a) was 29 (25th-75th percentile: 12–137) nmol/L. A total of 1,053 pts (11.7%) had a high Lp(a) (≥200 nmol/L). In the pooled trial population, high Lp(a) concentration was associated with a 29% higher risk of MACE (9.1% vs 7.6%; adjusted hazard ratio [adj HR] 1.29, 95% confidence interval [CI] 1.02–1.62; p=0.03), including a 37% higher risk of MI (6.9% vs. 5.3%; adj HR 1.37, 95% CI 1.05–1.79; p=0.02). The hazard ratios for MACE with ticagrelor vs. placebo were 0.73 (95% CI 0.48–1.11) for patients with higher Lp(a) and 0.88 (95% CI 0.74–1.05) for patients with lower Lp(a) (p-interaction=0.41; Figure 1). The absolute risk reductions were 2.4% and 1.2%, respectively.

Conclusion

Lp(a) above 200 nmol/L identifies patients with prior MI at increased risk of MACE who may derive greater absolute risk reduction from treatment with ticagrelor. These exploratory observations provide insights for therapeutics that are evaluating the clinical benefit of Lp(a) reduction.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): The PEGASUS-TIMI 54 trial was funded by AstraZeneca

Antithrombotic therapy after percutaneous coronary intervention of bifurcation lesions

Coronary bifurcations exhibit localised turbulent flow and an enhanced propensity for atherothrombosis, platelet deposition and plaque rupture. Percutaneous coronary intervention (PCI) of bifurcation lesions is associated with an increased risk of thrombotic events. Such risk is modulated by anatomical complexity, intraprocedural factors and pharmacological therapy. There is no consensus on the appropriate PCI strategy or the optimal regimen and duration of antithrombotic treatment in order to decrease the risk of ischaemic and bleeding complications in the setting of coronary bifurcation. A uniform therapeutic approach meets a clinical need. The present initiative, promoted by the European Bifurcation Club (EBC), involves opinion leaders from Europe, America, and Asia with the aim of analysing the currently available evidence. Although mainly derived from small dedicated studies, substudies of large trials or from authors' opinions, an algorithm for the optimal management of patients undergoing bifurcation PCI, developed on the basis of clinical presentation, bleeding risk, and intraprocedural strategy, is proposed here.

Choice of P2Y12 inhibitor and clinical outcomes in the AUGUSTUS study: support for an individualised approach

Background

AUGUSTUS randomized patients with atrial fibrillation and ACS and/or PCI to apixaban or VKA and aspirin or placebo for 6 months on background P2Y12 inhibitor.

Purpose

To characterise the clinical outcomes in patients receiving clopidogrel or ticagrelor.

Methods

Patients enrolled in AUGUSTUS (n=4614) were grouped by P2Y12 inhibitor at randomization. Baseline characteristics were compared among groups. Rates of ISTH major or CRNM bleeding, definite/probable stent thrombosis (ST), stroke, MI, and death or ischaemic event were quantified and treatment groups were compared according to treatment with clopidogrel or ticagrelor.

Results

At randomization, patients were treated with clopidogrel (n=4165), ticagrelor (n=280), prasugrel (n=51) or no P2Y12 inhibitor (n=118). Median ages were 71, 69, 66 and 72 years (P<0.001). Ticagrelor and prasugrel were more commonly used in PCI-managed ACS (53% and 55%) whilst clopidogrel or no P2Y12 inhibitor was more common in medically-managed ACS (25% and 36%); elective PCI was the index event in 37–41% for each group. Irrespective of P2Y12 inhibitor used, bleeding risk was lower with apixaban vs. VKA and higher with aspirin vs. placebo (Table). ST rate was lowest but major/CRNM bleeding rate highest with ticagrelor + aspirin vs ticagrelor without aspirin or clopidogrel with or without aspirin.

Conclusions

Apixaban is safer than VKA regardless of P2Y12 inhibitor used. Dropping aspirin reduces bleeding but is associated with numerically higher ST rates regardless of P2Y12 inhibitor used. These data support current recommendations for preferential use of NOAC vs. VKA and individualised choice of P2Y12 inhibitor and timing of aspirin cessation after PCI according to the patient's risks of bleeding and stent thrombosis.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Bristol-Myers Squibb/Pfizer

P6411Dyspnea in ticagrelor treated patients in the all-comer randomized GLOBAL LEADERS study and its association with clinical outcomes

Background

Dyspnea represents a drug adverse effect reported with a higher frequency for ticagrelor, as compared with other P2Y12 antagonists. The impact of dyspnea on clinical outcomes has not been yet evaluated in the context of aspirin-free therapies after percutaneous coronary intervention (PCI).

Purpose

The study aimed to evaluate the incidence of dyspnea and its associations with demographic characteristics and clinical outcomes in patients undergoing PCI treated with ticagrelor either as monotherapy or as a part of a dual antiplatelet therapy (DAPT) in the GLOBAL LEADERS cohort.

Methods

This is a sub-analysis of the randomized all-comer GLOBAL LEADERS study (n=15991), comparing the experimental strategy of ticagrelor monotherapy following one-month DAPT after PCI with the reference strategy of 12-month DAPT followed by 12-month aspirin monotherapy. The incidence of dyspnea reported as adverse event (AE) and its relation to demographic characteristics and 2-year clinical outcomes was evaluated (intention-to-treat analysis). Multivariable Cox proportional hazards models were performed, including randomized treatment and incidence of first dyspnea event as a time-dependent covariate. The primary endpoint was a composite of 2-year all-cause mortality or centrally adjudicated, new Q-wave myocardial infarction (MI). Patient-oriented clinical endpoints (POCE) comprised all-cause death, any stroke, MI or revascularization, whereas net adverse clinical events (NACE) included POCE and Bleeding Academic Research Consortium (BARC)-defined bleeding type 3 or 5.

Results

Overall, dyspnea was reported as an AE in 2101 patients (13.2%) up to two years of follow-up, with a higher frequency in the experimental arm (16.4%) as compared with the reference group (11.1%) (hazard ratio [HR]1.70, 95% confidence interval [CI] 1.56–1.86, p=0.001).

Predictors of dyspnea AE up to 2 years by multivariate analyses were: chronic obstructive pulmonary disease (HR1.71, 95% CI 1.56–1.87, p=0.001), female gender (HR1.31, 95% CI 1.18–1.44, p=0.001), hypertension (HR1.31, 95% CI 1.19–1.44, p=0.001, prior coronary artery bypass grafting (HR1.30, 95% CI 1.10–1.54, p=0.003), left ventricle ejection fraction below 40% (HR1.22, 95% CI 1.04–1.42, p=0.012), presentation with acute coronary syndrome (HR1.19, 95% CI 1.09–1.29, p=0.001) and body mass index (≥27kg/m2) (HR1.17, 95% CI 1.08–1.28, p=0.001).

In patients who reported dyspnea AE, the two-year rates of the efficacy and safety endpoints in the experimental and reference arm were: for the primary endpoint 3.4% vs. 4.3% (p adjusted=0.807), for POCE 15.8% vs. 17.6% (p adjusted=0.218), for NACE 17.2% vs. 19.6% (p adjusted=0.082), for BARC 3 or 5 type bleeding 17.2% vs. 19.6% (p adjusted=0.082), respectively.

Conclusions

The occurrence of dyspnea AE up to two years after PCI appeared not to affect the safety of the experimental treatment strategy of 23-month ticagrelor monotherapy following one-month DAPT after PCI.

Acknowledgement/Funding

Study founded by European Cardiovascular Research Institute, which received unrestricted grants from Biosensors Int., AstraZeneca, Medicines Company.

Open Multicentre Study of the P 2T Receptor Antagonist AR-C69931MX Assessing Safety, Tolerability and Activity in Patients with Acute Coronary Syndromes

Platelet aggregation is the central process in the pathophysiology of acute coronary syndromes. ADP contributes to thrombosis by activating platelets, and AR-C69931MX is a specific antagonist of this process acting at the P 2T receptor. At 5 hospitals, 39 patients with unstable angina or non-Q wave myocardial infarction, who were receiving aspirin and heparin, were administered intravenous AR-C69931MX with stepped dose increments over 3 h to a plateau of either 2 μg/kg/min for 21 h (Part 1; n = 12) or up to 69 h (Part 2; n = 13) or 4 μg/kg/min for up to 69 h (Part 3: n = 14). Safety parameters, platelet aggregation (PA) induced by ADP 3 μmol/L (impedance aggregometry), bleeding time (BT) and plasma concentrations of AR-C69931XX were assessed. AR-C69931MX was well tolerated. 33 patients completed the study. There were no deaths at 30 days and no serious adverse events attributed to AR-C69931MX. Trivial bleeding (56%) was common. At 24 h, mean inhibition of PA was 96.0 ± 8.6, 94.9 ± 14.4 and 98.7 ± 2.1% and BT was 9.5 ± 8.4, 14.0 ± 9.7 and 16.0 ± 11.1 min for Parts 1, 2 and 3 respectively. At 1 h post-infusion, mean inhibition of PA was 36.2 ± 39.2, 20.7 ± 25.9 and 40.7 ± 36.7% respectively. 90% patients had a plasma half-life for AR-C69931XX of 9 min. In conclusion, AR-C69931MX is a potent, short-acting platelet ADP receptor antagonist suitable for further studies as an antithrombotic agent.

A Whole Blood Assay of Inhibition of Platelet Aggregation by Glycoprotein IIb/IIIa Antagonists: Comparison with other Aggregation Methodologies

We have used a whole blood single-platelet counting assay (WBSPC) that is sensitive to microaggregation for monitoring GPIIb/IIIa antagonists and have compared this with other methodologies. In vitro effects of the GPIIb/IIIa antagonist fradafiban on ADP-induced platelet aggregation were determined using WBSPC and PRP turbidimetry, comparing citrate and hirudin anticoagulation. Fradafiban was a more potent inhibitor of aggregation assessed by PRP turbidimetry compared to WBSPC. Citrate showed only a trend towards enhancing fradafiban potency (p = 0.087). Citrated blood from 8 patients with unstable angina, randomised to receive oral lefradafiban (the oral prodrug of fradafiban) or placebo, was studied before and during treatment using WBSPC, PRP turbidimetry, impedance aggregometry and Rapid Platelet Function Assay (RPFA, Accumetrics). RPFA, PRP turbidimetry and WBSPC measurements correlated well. Impedance aggregometry responses were oversensitive to GPIIb/IIIa blockade. WBSPC was most discriminating at high levels of inhibition and offered a rapid means of monitoring GPIIb/IIIa antagonist effect within the therapeutic range of inhibition.

Inhibition of ADP-induced P-selectin Expression and Platelet-Leukocyte Conjugate Formation by Clopidogrel and the P2Y12 Receptor Antagonist AR-C69931MX but not Aspirin

Platelet-leukocyte interactions are recognised to have pro-inflammatory effects, which may be important in the pathophysiology of ischaemic heart disease. Clopidogrel and the novel intravenous antithrombotic agent AR-C69931MX act at the level of the platelet P2Y12 receptor, which is known to amplify platelet activation, aggregation and other responses induced by numerous platelet agonists. We studied the effects of clopidogrel and aspirin on ADP-induced platelet-leukocyte conjugate formation and P-selectin expression in healthy volunteers. The effects of clopidogrel and AR-C69931MX administered to patients with ischaemic heart disease were also assessed. AR-C69931MX and aspirin were also studied in vitro. Clopidogrel and AR-C69931MX suppressed ADP-induced platelet aggregation, P-selectin expression and platelet-leukocyte conjugate formation whereas aspirin had no inhibitory effect. These effects of clopidogrel and AR-C69931MX may confer therapeutic benefits in the management of acute coronary syndromes.

Hirudin anticoagulation allows more rapid determination of P2Y12 inhibition by the VerifyNow P2Y12 assay

VerifyNow (VN) P2Y12 is a point-of-care assay used to assess response to P2Y12 inhibitors. Sodium citrate (citrate) is the standard anticoagulant used for this assay but requires a pre-incubation period. Hirudin is an alternative anticoagulant for platelet function studies that maintains physiological divalent cation levels. We investigated whether hirudin anticoagulation might allow more rapid testing of P2Y12 inhibition at the time of percutaneous coronary intervention (PCI). Blood was collected from the arterial sheath of aspirin-treated patients undergoing elective, urgent or emergency coronary angiography ± PCI and aliquots were anticoagulated with either citrate or hirudin. For each anticoagulant, VN P2Y12 was performed both immediately and after 20 minutes. A total of 98 patients were included in this study following pre-treatment with clopidogrel (n = 88), prasugrel (n = 6) or no P2Y12 inhibitor (n = 4). PRU with hirudin immediately (PRU_H_Imm) and PRU with citrate 20 minutes post sampling (PRU_C_20) were very strongly correlated (R = 0.95) though PRU_H_Imm tended to be lower than PRU_C_20 so that optimal correlation was estimated by the equation PRU_H_Imm = 0.95 x PRU_C_20 (p < 0.001). Bland-Altman plots showed good agreement between PRU_H_Imm and (0.95 x PRU_C_20). Platelet reactivity was more stable over the studied time course with hirudin as compared to citrate. We therefore conclude that VN P2Y12 with hirudin anticoagulation can be performed more rapidly and results are strongly correlated with delayed citrate measurements. Further studies are warranted to assess the utility of this method for improving clinical outcomes in patients undergoing PCI.

Relationship between degree of P2Y12 receptor blockade and inhibition of P2Y12-mediated platelet function

The thienopyridine P2Y12 receptor antagonists clopidogrel and prasugrel prevent arterial thrombosis and are routinely used following percutaneous coronary intervention. However, the optimal level of P2Y12 blockade to effectively inhibit platelet function is unknown. These studies utilised the active metabolite of prasugrel (R-138727) to achieve a range of P2Y12 blockade in vitro and assessed several aspects of platelet function. Blood from healthy volunteers was incubated with R-138727 (0–10 μM). P2Y12 receptor number was assessed using a 33P-2MeSADP binding assay. Platelet aggregation (PA) was measured by optical aggregometry with ADP 2–20 μM. VASP phosphorylation, annexin V binding, microparticle formation and P-selectin expression were assessed by flow cytometry. Increasing numbers of unblocked receptors were required for a sustained aggregation response with decreasing concentrations of ADP. A P2Y12 receptor blockade of 60–80% resulted in strong inhibition of final PA response, P-selectin expression, microparticle formation and vasodilator-stimulated phosphoprotein (VASP). PA induced by ADP 2 μM and P-selectin expression were particularly sensitive to low levels of receptor blockade whereas the VASP phosphorylation assay was relatively insensitive, requiring 60% receptor blockade to achieve substantial inhibition. Different assays varied in their ability to discriminate particular ranges of P2Y12 blockade and 80% or greater P2Y12 receptor blockade is required for consistently strong inhibition of several aspects of platelet function. These data guide the interpretation of results from different assays used to monitor the effects of P2Y12 receptor antagonists.

Non-vitamin K antagonist oral anticoagulants (NOACs): clinical evidence and therapeutic considerations

Warfarin, a vitamin K antagonist, is the most widely used oral anticoagulant in the world. It is cheap and effective, but its use is limited in many patients by unpredictable levels of anticoagulation, which increases the risk of thromboembolic or haemorrhagic complications. It also requires regular blood monitoring and dose adjustment. New classes of drugs, non-vitamin K antagonist oral anticoagulants (NOACs), are now supported as alternatives to warfarin. Three NOACs are licensed: dabigatran, a direct thrombin inhibitor, and rivaroxaban and apixaban, antagonists of factor Xa. NOACs do not require routine blood monitoring or dose adjustment. They have a rapid onset and offset of action and fewer food and drug interactions. Current indications include treatment and prophylaxis of venous thromboembolism and prevention of cardioembolic disease in non-valvular atrial fibrillation. Effective antidotes are lacking and some caution must be used in severe renal impairment, but favourable trial evidence has led to their widespread adoption. Research is ongoing, and an increase in their use and indications is expected in the coming years.

The oncological outcome after right hemicolectomy and accuracy of CT scan as a preoperative tool for staging in right sided colonic cancers

AIM

Neoadjuvant chemotherapy may have a role in the management of colonic carcinoma but clinical trials are required to determine whether this approach is superior to the standard policy of radical surgery, high-quality histopathology and selective postoperative chemotherapy. The selection of appropriate patients for such trials will depend on accurate locoregional staging of disease by preoperative CT scanning. We studied the outcome after radical right hemicolectomy and assessed the accuracy of preoperative CT scans in the prediction of postoperative pathology.

METHOD

A retrospective analysis of right hemicolectomies performed with curative intent for colon cancer under the care of a single colorectal surgeon (D.J.A.) was performed. Preoperative CT-proven Dukes D patients were excluded. Patient demographics, postoperative histology, use of adjuvant chemotherapy and survival data were collected. Kaplan-Meier curves were constructed and log-rank testing was performed to compare cancer-specific survival. Fifty patients had their preoperative CT scan images reviewed by two radiologists both blinded to the results of the postoperative histology. The accuracy of preoperative CT for T and N staging was studied. A P-value of < 0.05 was significant.

RESULTS

There were 136 patients (79 women). Median age was 76 (interquartile ratio 67-82) years. Median period of follow-up was 72 (interquartile ratio 39-92) months. There were 56 deaths (39 medical, 16 oncological and 1 postoperative). There were three groups of patients: node negative (n = 84), node positive with postoperative adjuvant chemotherapy (n = 30) and node positive without chemotherapy (n = 22). Five-year cancer-specific survival for node negative disease was 84% and was poorer for node positive patients who received adjuvant chemotherapy when compared with those who did not (62 vs 72%, P-value = 0.046 on log-rank testing). Sensitivity, specificity, positive and negative predictive value of CT scan for tumour (T) stage were 90, 33, 86 and 43% respectively, while that for nodal (N) stage was 83, 38, 57 and 69%, respectively.

CONCLUSION

CT scan has limited accuracy in predicting those patients with advanced locoregional disease who might benefit from neoadjuvant treatment. When this finding is combined with relatively high cancer-specific survival with surgery alone the impact of adjuvant chemotherapy on survival after radical surgery for right colon carcinoma may be marginal.

QTL involved in the modification of cyanidin compounds in black and red raspberry fruit

Fruit from Rubus species are highly valued for their flavor and nutritive qualities. Anthocyanin content contributes to these qualities, and although many studies have been conducted to identify and quantify the major anthocyanin compounds from various Rubus species, the genetic control of the accumulation of these complex traits in Rubus is not yet well understood. The identification of the regions of the genome involved in the production of anthocyanins is an important first step in identifying the genes underlying their expression. In this study, ultra and high-performance liquid chromatography (UHPLC and HPLC) and two newly developed Rubus linkage maps were used to conduct QTL analyses to explore the presence of associations between concentrations of five anthocyanins in fruit and genotype. In total, 27 QTL were identified on the Rubus linkage maps, four of which are associated with molecular markers designed from transcription factors and three of which are associated with molecular markers designed from anthocyanin biosynthetic pathway candidate genes. The results of this study suggest that, while QTL for anthocyanin accumulation have been identified on six of seven Rubus linkage groups (RLG), the QTL on RLG2 and RLG7 may be very important for genetic control of cyanidin modification in Rubus.