Laura Melton

Duke University, Durham, North Carolina, United States

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Publications (5)48.55 Total impact

  • [Show abstract] [Hide abstract] ABSTRACT: Erythropoietin (EPO) was hypothesized to mitigate reperfusion injury, in part via mobilization of endothelial progenitor cells (EPCs). The REVEAL trial found no reduction in infarct size with a single dose of EPO (60,000 U) in patients with ST-segment elevation myocardial infarction. In a substudy, we aimed to determine the feasibility of cryopreserving and centrally analyzing EPC levels to assess the relationship between EPC numbers, EPO administration, and infarct size. As a prespecified substudy, mononuclear cells were locally cryopreserved before as well as 24 and 48-72 h after primary percutaneous coronary intervention. EPC samples were collected in 163 of 222 enrolled patients. At least one sample was obtained from 125 patients, and all three time points were available in 83 patients. There were no significant differences in the absolute EPC numbers over time or between EPO- and placebo-treated patients; however, there was a trend toward a greater increase in EPC levels from 24 to 48-72 h postintervention in patients receiving ≥30,000 U of EPO (P = 0.099 for CD133(+) cells, 0.049 for CD34(+) cells, 0.099 for ALDH(br) cells). EPC numbers at baseline were inversely related to infarct size (P = 0.03 for CD133(+) cells, 0.006 for CD34(+) cells). Local whole cell cryopreservation and central EPC analysis in the context of a multicenter randomized trial is feasible but challenging. High-dose (≥30,000 U) EPO may mobilize EPCs at 48-72 h, and baseline EPC levels may be inversely associated with infarct size.
    No preview · Article · May 2013 · Journal of Thrombosis and Thrombolysis
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    [Show abstract] [Hide abstract] ABSTRACT: Acute ST-segment elevation myocardial infarction (STEMI) is a leading cause of morbidity and mortality. In experimental models of MI, erythropoietin reduces infarct size and improves left ventricular (LV) function. To evaluate the safety and efficacy of a single intravenous bolus of epoetin alfa in patients with STEMI. A prospective, randomized, double-blind, placebo-controlled trial with a dose-escalation safety phase and a single dose (60,000 U of epoetin alfa) efficacy phase; the Reduction of Infarct Expansion and Ventricular Remodeling With Erythropoietin After Large Myocardial Infarction (REVEAL) trial was conducted at 28 US sites between October 2006 and February 2010, and included 222 patients with STEMI who underwent successful percutaneous coronary intervention (PCI) as a primary or rescue reperfusion strategy. Participants were randomly assigned to treatment with intravenous epoetin alfa or matching saline placebo administered within 4 hours of reperfusion. Infarct size, expressed as percentage of LV mass, assessed by cardiac magnetic resonance (CMR) imaging performed 2 to 6 days after study medication administration (first CMR) and again 12 ± 2 weeks later (second CMR). In the efficacy cohort, the infarct size did not differ between groups on either the first CMR scan (n = 136; 15.8% LV mass [95% confidence interval {CI}, 13.3-18.2% LV mass] for the epoetin alfa group vs 15.0% LV mass [95% CI, 12.6-17.3% LV mass] for the placebo group; P = .67) or on the second CMR scan (n = 124; 10.6% LV mass [95% CI, 8.4-12.8% LV mass] vs 10.4% LV mass [95% CI, 8.5-12.3% LV mass], respectively; P = .89). In a prespecified analysis of patients aged 70 years or older (n = 21), the mean infarct size within the first week (first CMR) was larger in the epoetin alfa group (19.9% LV mass; 95% CI, 14.0-25.7% LV mass) than in the placebo group (11.7% LV mass; 95% CI, 7.2-16.1% LV mass) (P = .03). In the safety cohort, of the 125 patients who received epoetin alfa, the composite outcome of death, MI, stroke, or stent thrombosis occurred in 5 (4.0%; 95% CI, 1.31%-9.09%) but in none of the 97 who received placebo (P = .04). In patients with STEMI who had successful reperfusion with primary or rescue PCI, a single intravenous bolus of epoetin alfa within 4 hours of PCI did not reduce infarct size and was associated with higher rates of adverse cardiovascular events. Subgroup analyses raised concerns about an increase in infarct size among older patients. Identifier: NCT00378352.
    Full-text · Article · May 2011 · JAMA The Journal of the American Medical Association
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    [Show abstract] [Hide abstract] ABSTRACT: Acute myocardial infarction (MI) remains a leading cause of death despite advances in pharmacologic and percutaneous therapies. Animal models of ischemia/reperfusion have demonstrated that single-dose erythropoietin may reduce infarct size, decrease apoptosis, and increase neovascularization, possibly through mobilization of endothelial progenitor cells. REVEAL is a randomized, double-blind, placebo-controlled, multicenter trial evaluating the effects of epoetin α on infarct size and left ventricular remodeling in patients with large MIs. The trial comprises a dose-escalation safety phase and a single-dose efficacy phase using the highest acceptable epoetin α dose up to 60,000 IU. Up to 250 ST-segment elevation myocardial infarction patients undergoing primary or rescue percutaneous coronary intervention will be randomized to intravenous epoetin α or placebo within 4 hours of successful reperfusion. The primary study end point is infarct size expressed as a percentage of left ventricular mass, as measured by cardiac magnetic resonance imaging 2 to 6 days post study medication administration. Secondary end points will assess changes in endothelial progenitor cell numbers and changes in indices of ventricular remodeling. The REVEAL trial will evaluate the safety and efficacy of the highest tolerated single dose of epoetin α in patients who have undergone successful rescue or primary percutaneous coronary intervention for acute ST-segment elevation myocardial infarction.
    Full-text · Article · Nov 2010 · American heart journal
  • [Show abstract] [Hide abstract] ABSTRACT: Inhibition of the P2Y12 ADP-receptor with oral antiplatelet agents given to patients undergoing primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI) is associated with improved outcomes, but this strategy is limited by the time required for maximal antiplatelet effect after administration. We examined the safety and tolerability of a novel, direct-acting, reversible, intravenous P2Y12 ADP-receptor antagonist, elinogrel, versus placebo when administered to STEMI patients before primary PCI. The ERASE MI trial was a pilot, phase IIA, randomized, double-blind, placebo-controlled, dose-escalation study designed to evaluate the safety and tolerability of escalating doses (10, 20, 40, and 60 mg) of elinogrel administered as a single intravenous bolus before the start of the diagnostic angiogram preceding primary PCI. Patients were randomly assigned in a 1:1 manner to either elinogrel or placebo within each dosing group; and all patients received a 600-mg clopidogrel loading dose, followed by a second 300-mg clopidogrel loading dose 4 hours after PCI. The major outcome, in-hospital bleeding, was assessed with the Thrombolysis in Myocardial Infarction and Global Strategies to Open Occluded Coronary Arteries bleeding scales. Pre-PCI corrected Thrombolysis in Myocardial Infarction frame count and ST-segment resolution were also evaluated. Seventy patients were randomized in the dose-escalation study, but the dose-confirmation phase was not started because the trial was prematurely terminated for administrative reasons. The incidence of bleeding events was infrequent and appeared to be similar in patients treated with all doses of elinogrel versus placebo. No differences in serious adverse events, laboratory values, corrected Thrombolysis in Myocardial Infarction frame count, or ST resolution were demonstrated between elinogrel and placebo. With the limitations of a small study sample size, this pilot study provided preliminary data on the feasibility and tolerability of escalating doses of a direct-acting, reversible, intravenous P2Y12 ADP-receptor antagonist, elinogrel, as an adjunctive therapy for primary PCI for STEMI.
    No preview · Article · Dec 2009 · American heart journal
  • [Show abstract] [Hide abstract] ABSTRACT: Interest in the biology of endogenous progenitor cells (EPCs) continues to grow as evidence of their role in vascular repair mounts. EPC enumeration requires specialized laboratory techniques and is performed immediately after sample acquisition, limiting the clinical contexts in which EPC enumeration can be performed and the ability to increase sample sizes through multi-center participation. We compared the numbers of EPCs enumerated in samples processed immediately after acquisition (n = 36) with EPCs enumerated in specimens stored for 24 hours or after cryopreservation of mononuclear cells (MNC) using two EPC identification strategies: cell surface marker expression (CD133/CD34) and aldehyde dehydrogenase activity (ALDH(br) cells). EPCs assessed in fresh samples correlated with EPCs enumerated after whole blood storage (r = 0.699 for CD133(+)CD34(+) cells, r = 0.880 for ALDH(br) cells, P < 0.005 and P < 0.0001, respectively) or mononuclear cryopreservation (r = 0.590 for CD133(+)CD34(+) cells, r = 0.894 for ALDH(br) cells, P < 0.0001 for each); however, correlation based on assessment of ALDH(br) cells was higher (P < 0.0003 for comparison of correlation coefficients). Initial results from a multi-site clinical trial suggest that EPC enumeration after mononuclear cell cryopreservation is feasible. EPC analysis based on ALDH activity is reproducible, even after extended whole blood storage or MNC cryopreservation.
    No preview · Article · Oct 2009 · Journal of Thrombosis and Thrombolysis