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J E Tcheng

Publications and source records attributed to J E Tcheng.

At least 37 records · Page 2Linked to original sources
PubMed2000

Economic assessment of platelet glycoprotein IIb/IIIa receptor blockade with abciximab and low-dose heparin during percutaneous coronary revascularization: results from the EPILOG randomized trial. Evaluation in PTCA to Improve Long-term Outcome with abciximab GP IIb/IIIa blockade.

BACKGROUND: In the EPILOG trial (Evaluation in PTCA to Improve Long-term Outcome with abciximab GP IIb/IIIa blockade), abciximab administered with weight-adjusted heparin diminished the risk of ischemic complications within 30 days by 56% among patients undergoing percutaneous coronary revascularization, without increased bleeding complications. METHODS AND RESULTS: A prospective economic assessment was performed in the 2792 patients enrolled in EPILOG. Patients were randomized to receive placebo with standard-dose weight-adjusted heparin, abciximab with low-dose weight-adjusted heparin, or abciximab with standard-dose weight-adjusted heparin during percutaneous coronary intervention. Hospital billing data for the baseline hospitalization were collected for 2581 patients (92.4% of total) and imputed for the remainder, with physician fees estimated from the Medicare Fee Schedule. For the baseline hospitalization, medical costs (hospitalization and physician fees) averaged $9632 for the placebo arm compared with $8758 (P:=0.005) and $9092 (P:=0.176) for the abciximab with low-dose and standard-dose heparin arms, respectively. Inclusive of average drug cost ($1454 to $1457), the net incremental baseline cost of these 2 abciximab strategies was $583 with low-dose weight-adjusted heparin and $914 with standard-dose weight-adjusted heparin. During 6-month follow-up, average hospital costs were not significantly different in the 3 treatment groups; cumulative net incremental costs were $1236 and $1268 in the abciximab with low-dose and standard-dose heparin groups, respectively. CONCLUSIONS: Treatment with abciximab and low-dose, weight-adjusted heparin during percutaneous coronary revascularization reduces ischemic events and associated costs, thereby offsetting some of the cost of the drug. The suppression of bleeding complications associated with this agent by heparin dose reduction optimizes the economic attractiveness of this treatment strategy.

Abciximab↗
PubMed2000

The benefit of abciximab in percutaneous coronary revascularization is not device-specific.

Abciximab has been shown to decrease adverse outcomes after percutaneous coronary interventions, but it is unclear whether this beneficial effect is more or less pronounced with specific devices. This study sought to determine the relative magnitude of the benefit of abciximab among different interventional devices. Data from the 5 placebo-controlled trials of abciximab during coronary intervention were pooled. Patients were divided into groups based on whether they received balloon angioplasty alone, elective stenting, bailout stenting, or directional coronary atherectomy. In the patients undergoing balloon angioplasty, the 30-day hazard ratio for death or myocardial infarction (MI) in the group randomized to abciximab versus the placebo-treated group was 0.52 (p <0.001), for elective stenting the hazard ratio was 0.51 (p <0.001), for bailout stenting the hazard ratio was 0.38 (p <0.001), and for directional coronary atherectomy the hazard ratio was 0.38 (p = 0.007). A Cox proportional-hazards model revealed that overall, the use of abciximab decreased the composite end point of 30-day death or MI rates (hazard ratio 0.55, 95% confidence interval 0.43 to 0.69, p <0. 001). However, bailout stenting and directional coronary atherectomy were associated with increased rates of death or MI compared with balloon angioplasty, as was elective stenting in women compared with men. There was no significant increase in major bleeding episodes associated with abciximab in any of the device categories. These findings from all the controlled coronary revascularization trials using abciximab demonstrate that a decrease in death and MI is achieved with abciximab regardless of the type of device used, without an increase in significant bleeding complications.

Abciximab↗
PubMed2000

Timing of and risk factors for myocardial ischemic events after percutaneous coronary intervention (IMPACT-II). Integrilin to Minimize Platelet Aggregation and Coronary Thrombosis.

We studied both the time course and risk factors for adverse clinical events after percutaneous coronary intervention (PCI). Such information is critical to clinical decision-making, but scant quantitative data exist to describe the time course of these adverse outcomes. Patients enrolled in the Integrilin to Minimize Platelet Aggregation and Coronary Thrombosis-II (IMPACT-II) trial were analyzed. Patients undergoing elective, urgent, or emergency PCI (n = 4,010) were randomized to receive either placebo or 1 of 2 eptifibatide regimens during intervention. We evaluated the time to the primary end point of the trial, the 30-day composite of death, myocardial infarction, repeat nonelective PCI, nonelective bypass surgery, or stenting for abrupt closure. Adverse events occurred in 407 patients (10.1%). Because the risk of events declined substantially between 6 and 9 hours (66% occurred within 6 hours), events were classified as occurring before or after 6 hours. Independent predictors of "early" events included dissection, pre- and postprocedural coronary blood flow, side-branch occlusion, procedural thrombolytic use, previous bypass, presentation with unstable angina, absence of diabetes, and hyperlipidemia. The predictors of "late" events included lower weight, increased baseline heart rate, coronary dissection, and procedural thrombolytic use. The risk of ischemic events were greatest immediately after PCI and rapidly declined, so that by 9 hours the hazard function plot was flat; 66% of events occurred within 6 hours of PCI. Knowledge of the risk factors for early and late events help risk-stratify patients before and after intervention for myocardial ischemic events.

Aged↗
PubMed2000

Efficacy of abciximab readministration in coronary intervention.

Abciximab, an Fab monoclonal antibody fragment that blocks the platelet glycoprotein IIb/IIIa receptor, is increasingly used as an adjunct to coronary intervention. Little is known, however, about the efficacy and safety of readministration of abciximab. This study examined and characterized outcomes of patients receiving abciximab for a second time. From April 1995 to June 1997, 164 consecutive patients were readministered abciximab at our 3 institutions. We retrospectively examined and analyzed in-hospital outcomes in this cohort. The median time to readministration was 95 days. The angiographic success rate of percutaneous intervention was 99.5%. Rates and 95% confidence intervals of in-hospital events were death 2% (0.7% to 6.1%), myocardial infarction 3% (1% to 7%), coronary bypass surgery 0% (0% to 2.2%), and intracranial hemorrhage 2% (0.4% to 5.3%). Severe thrombocytopenia was observed in 4% of patients (1.4% to 7.8%) after readministration. Allergic or anaphylactic reactions were not observed. Major bleeding was associated with excessive concomitant antithrombotic therapy. Patients undergoing readministration of abciximab within 2 weeks of first administration experienced a higher incidence of severe thrombocytopenia (12% vs. 2%, p = 0.046). Thus, abciximab remains clinically efficacious when readministered as an adjunct to percutaneous coronary intervention. However, concomitant heparin administration must be carefully monitored and warfarin therapy should be avoided. Vigilant surveillance for thrombocytopenia should be employed. Reduced dosing may be necessary when abciximab is readministered within days of the initial administration.

Abciximab↗
PubMed2000

Outcomes following interventions in small coronary arteries with the use of hand-crimped Palmaz-Schatz stents.

Although coronary stenting has been shown to be effective, retrospective studies have suggested that stents do not provide better results than angioplasty in small coronary arteries. We sought to examine procedural, in-hospital, and long-term outcomes of patients undergoing small-vessel stenting with Palmaz-Schatz stents hand-crimped on a balloon catheter <3 mm in diameter. We retrospectively analyzed the outcomes of 117 patients who underwent this type of coronary stent implantation at Duke University Medical Center between January 1, 1997 and May 30, 1998. The clinical indications for percutaneous revascularization included unstable angina in 67.5% of patients, acute myocardial infarction in 4.3%, postinfarct angina in 3.4%, silent ischemia in 3.4%, and stable angina in 1% of patients. Quantitative angiographic analysis was performed immediately before angioplasty and after stent implantation. Stents were used for elective indications in 24%, for suboptimal angiographic result in 61.5%, and for abrupt and/or threatened closure in 14.5% of patients. Reference vessel diameter was similar before and after the procedure. Minimum luminal diameter increased from 0.63 to 2.35 mm, an acute gain of 1.72+/-0.43 mm. Percent stenosis decreased from 74.2% to 4.7%. The clinical composite of death (n = 1, 1%), nonfatal myocardial infarction (n = 6, 5.1%), and revascularization (n = 1, 1%) occurred in-hospital in only 8 patients (6.8%), resulting in clinical procedure success in 109 patients (93%). Our data suggest that stents designed for vessels >3.0 mm can be deployed in small vessels, with a low in-hospital event rate. However, target lesion revascularization in small vessels remains high. Development of antiproliferative strategies could improve long-term outcomes for small-vessel interventions.

Aged↗
PubMed2000

Local delivery of heparin post-PTCA: a multicenter randomized pilot study.

Bailout stenting for major dissection and threatened closure has high rates of ischemic complications. We performed a randomized trial of local heparin delivery using the infusion sleeve before bailout stenting for suboptimal angioplasty results. In phase I, 20 patients were randomized to local delivery with either 40- or 100-psi infusion pressure. In phase II, 37 patients were randomized to local delivery at 100 psi or standard therapy. Local delivery succeeded in all but one patient; overall there was no significant worsening of intimal dissection. One patient treated with 100-psi drug infusion suffered a perforation after stent placement. There were no significant differences in the composite endpoint of death, MI, CABG, urgent repeat angioplasty, and stent thrombosis at 30 days (21% vs. 0%; P = 0.18). At 6 months, the rates of myocardial infarction in phase II were 27% with local delivery vs. 10% with standard treatment (P = 0.4). Local heparin delivery in dissected vessels may be associated with increased complications and should be approached with caution.

Aged↗
PubMed2000

Abciximab and bleeding during coronary surgery: results from the EPILOG and EPISTENT trials. Improve Long-term Outcome with abciximab GP IIb/IIIa blockade. Evaluation of Platelet IIb/IIIa Inhibition in STENTing.

BACKGROUND: Abciximab during percutaneous coronary revascularization reduces ischemic complications, but concern exists regarding increased bleeding risk should emergency coronary surgical procedures be required. METHODS: Outcomes were assessed among 85 patients who required coronary artery bypass grafting operations after coronary intervention in two randomized placebo-controlled trials of abciximab. Comparisons were made between patients in the pooled placebo and abciximab groups. RESULTS: The incidence of coronary surgical procedures was 2.17% and 1.28% among patients randomized to placebo and abciximab, respectively (p = 0.021). Platelet transfusions were administered to 32% and 52% of patients in the placebo and abciximab groups, respectively (p = 0.059). Rates of major blood loss were 79% and 88% in the placebo and abciximab groups, respectively (p = 0.27); transfusions of packed red blood cells or whole blood were administered in 74% and 80% of patients, respectively (p = 0.53). Surgical reexploration for bleeding was required in 3% and 12% of patients, respectively. Death and myocardial infarction tended to occur less frequently among patients who had received abciximab. CONCLUSIONS: Urgent coronary artery bypass grafting operations can be performed without an incremental increase in major hemorrhagic risk among patients on abciximab therapy.

Abciximab↗
PubMed2000

Clinical benefit of glycoprotein IIb/IIIa blockade with Abciximab is independent of gender: pooled analysis from EPIC, EPILOG and EPISTENT trials. Evaluation of 7E3 for the Prevention of Ischemic Complications. Evaluation in Percutaneous Transluminal Coronary Angioplasty to Improve Long-Term Outcome with Abciximab GP IIb/IIIa blockade. Evaluation of Platelet IIb/IIIa Inhibitor for Stent.

OBJECTIVES: We sought to determine the efficacy and safety of platelet glycoprotein IIb/IIIa receptor (GP IIb/IIIa) blockade with abciximab in women undergoing percutaneous coronary intervention. BACKGROUND: Although gender differences in response to platelet glycoprotein IIb/IIIa receptor blockade have been described, there have been no large clinical studies to assess these differences. METHODS: Outcomes were determined using meta-analysis technique. RESULTS: In the pooled analysis, the primary end point of death, myocardial infarction (MI) or urgent revascularization within 30 days was reduced from 11.3% to 5.8% (p<0.001) in men and from 12.7% to 6.5% (p<0.001) in women treated with abciximab. At six months, death, MI or urgent revascularization was reduced from 14.1% to 8.3% (p<0.001) in men and 16.0% to 9.9% (p<0.001) in women receiving abciximab. At one year, mortality was reduced from 2.7% to 1.9% (p = 0.06) in men and 4.0% to 2.5% (p = 0.03) in women treated with abciximab. Major bleeding events occurred in 2.9% versus 3.0% (p = 0.96) of women and 2.7% versus 1.3% (p = 0.003) of men treated with placebo versus abciximab, respectively. Minor bleeding events occurred in 4.7% versus 6.7% (p = 0.01) of women and 2.3% versus 2.2% (p = 0.94) of men treated with placebo versus abciximab, respectively. CONCLUSIONS: This pooled analysis demonstrated no gender difference in protection from major adverse outcomes with GP IIb/IIIa inhibition with abciximab. Although women had higher rates of both major and minor bleeding events with abciximab compared with men, major bleeding in women was similar with and without abciximab. There was a small increased risk of minor bleeding with abciximab in women.

Abciximab↗
PubMed2000

Provisional stenting strategies: systematic overview and implications for clinical decision-making.

Coronary stents reduce the rates of abrupt closure, emergency coronary artery bypass graft surgery and restenosis, but do not prevent myocardial infarction or death at six months. The financial burden of increased stent use and the difficulty in managing in-stent restenosis have provided the impetus to develop provisional stenting strategies. Patients at low risk for restenosis after balloon angioplasty may not derive additional benefit from stent implantation and may be successfully managed with percutaneous transluminal coronary angioplasty (PTCA) alone. Numerous patient, lesion and procedural predictors of restenosis have been identified. Postprocedural assessment using quantitative coronary angiography, intravascular ultrasound (IVUS), coronary flow velocity reserve (CVR) or fractional flow reserve (FFR) may further enhance the ability to predict adverse outcomes after PTCA. Several studies have been performed to investigate the feasibility of provisional stenting strategies using various modalities to identify low risk patients who could be managed with PTCA alone. An optimal or "stent-like" angiographic result after PTCA is associated with favorable clinical outcomes. Preliminary results of studies using IVUS or CVR to guide provisional stenting appear promising. Angiography alone may be inadequate to identify truly low risk patients and may need to be combined with clinical factors, assessment of recoil, IVUS or physiologic indexes. Strategies that avoid unnecessary stenting in even a small proportion of patients may have large impacts on health care costs. Provisional stenting may potentially reduce costs and rates of in-stent restenosis without compromising the quality of health care delivery.

Blood Vessel Prosthesis Implantation↗
PubMed2000

Clinical challenges of platelet glycoprotein IIb/IIIa receptor inhibitor therapy: bleeding, reversal, thrombocytopenia, and retreatment.

Randomized clinical trials of glycoprotein IIb/IIIa integrin inhibition during percutaneous coronary intervention and as adjunctive treatment of acute coronary syndromes have shown impressive clinical efficacy in reducing the morbidity and mortality rates of cardiovascular disease. Three agents are currently available in the United States: abciximab (ReoPro), eptifibatide (Integrilin), and tirofiban (Aggrastat). Pharmacodynamic studies show that abciximab is a high-affinity agent with a low dissociation constant; eptifibatide and tirofiban are high-specificity agents with higher dissociation constants and concentration-dependent antiplatelet effects. This article first reviews the relevant pharmacokinetic and pharmacodynamic properties of each of the agents. These principles are then applied to a discussion of the 4 primary clinical issues concerning their use: prevention of untoward bleeding, algorithms for acute reversal, recognition and treatment of thrombocytopenia, and the issue of readministration.

Eptifibatide↗
PubMed2000

Clinical correlates and course of thrombocytopenia during percutaneous coronary intervention in the era of abciximab platelet glycoprotein IIb/IIIa blockade.

BACKGROUND: Thrombocytopenia is infrequently associated with abciximab therapy but may contribute to hemorrhagic risk. Factors associated with development of thrombocytopenia, the role of weight-adjustment in concomitant heparin administration, and clinical outcomes in patients with thrombocytopenia are not well defined. METHODS AND RESULTS: Pooled data from 3 placebo-controlled, randomized trials (EPIC, EPILOG, and EPISTENT) of abciximab therapy during percutaneous coronary intervention identified 178 patients (2. 4% of 7290 patients) in whom thrombocytopenia (platelet count <100 x 10(9)/L) developed after enrollment. Multivariate regression analysis identified age (>65 years; P <.001), weight (<90 kg; P =. 023), baseline platelet count (<200 x 10(9)/L; P <.001), abciximab therapy (P =.002), and enrollment into the EPIC trial (P <.001) to be associated with development of thrombocytopenia. Major and minor nonsurgical hemorrhage and transfusion were more frequent (all P <. 001) in thrombocytopenic patients. Although the primary composite clinical end point of these trials (death, myocardial infarction, or urgent revascularization to 30 days) was observed with similar frequency in patients with (11.2%) and those without (7.9%; P =.114) thrombocytopenia, 30-day mortality rate was higher in thrombocytopenic patients (8.4% vs 0.6%, respectively; P <.001). This excess mortality rate persisted after excluding patients in whom thrombocytopenia was first noted after the performance of coronary bypass surgery (4.8% vs 0.6%; P <.001). Among patients in whom thrombocytopenia developed during these trials, those who received prophylactic abciximab had fewer primary end point events (7.1% vs 23.1%; P =.056) and had a lower 30-day mortality rate (3.5% vs 15.4%; P =.048) than patients with thrombocytopenia who had received prophylactic placebo. CONCLUSIONS: Thrombocytopenia associated with abciximab therapy for percutaneous coronary intervention was more frequent in older, lighter-weight patients, those with lower baseline platelet counts, and in those patients who were enrolled into the EPIC trial. Both bleeding and transfusion events occur more frequently in patients with thrombocytopenia. Patients in whom thrombocytopenia developed during these trials had increased mortality rates to 30 days not attributable to the performance of coronary bypass surgery. Among patients with thrombocytopenia, those who received prophylactic abciximab had better clinical outcomes including survival than those who did not.

Abciximab↗
PubMed2000

Design and methodology of the ESPRIT trial: evaluating a novel dosing regimen of eptifibatide in percutaneous coronary intervention.

BACKGROUND: Clinical trials of the glycoprotein (GP) IIb/IIIa inhibitors have shown that these potent antiplatelet agents are effective in reducing the ischemic complications of percutaneous coronary interventions. However, even though stents are now implanted in >75% of percutaneous interventional procedures, only one study, a trial of the monoclonal antibody abciximab, has formally evaluated adjunctive GP IIb/IIIa inhibition in this setting. METHODS AND RESULTS: Eptifibatide, a nonimmunogenic and rapidly reversible inhibitor of the platelet receptor integrin IIb/IIIa, has also undergone evaluation as an adjunct to coronary intervention. In clinical trials performed heretofore, however, it has appeared to have less relative clinical efficacy than the monoclonal antibody abciximab. Since the early seminal trials, it has been recognized that the doses of eptifibatide previously used achieved only 30% to 50% of maximal platelet GP IIb/IIIa integrin inhibition. This is considerably less than the 80% level of receptor inhibition that has been proposed to prevent coronary thrombus formation in animal models and that has been achieved in clinical trials with abciximab. CONCLUSIONS: The Enhanced Suppression of the Platelet IIb/IIIa Receptor with Integrilin Therapy (ESPRIT) trial was designed to test the safety and efficacy of a high-dose, "180/2.0/180" double-bolus regimen of eptifibatide (a 180-microg/kg bolus followed 10 minutes later by a second 180-microg/kg bolus of eptifibatide combined with a 2.0-microg/kg per minute infusion) as an adjunct to nonacute percutaneous coronary intervention with stent implantation. In this report, we review the rationale, design, and methods of this clinical investigation.

Angioplasty, Balloon, Coronary↗
PubMed2000

Effects of 308 nanometer excimer laser energy on 316 L stainless-steel stents: implications for laser atherectomy of in-stent restenosis.

PURPOSE: To determine the effects of the incidental exposure of stents to pulsed 308 nanometer ultraviolet excimer laser energy. METHODS: Five types of 316 L stainless-steel coronary stents were subjected to two types of study. First, for endurance testing, sixty stents were deployed in 3.0Eth 4.0 mm polymer tubes in three geometries. Up to 1,000 laser pulses were delivered while advancing a 2.0 mm eccentric catheter through the lumen of the stent. These stents were next subjected to 400 million simulated heartbeats and then analyzed for metal etching and fatigue. Second, six additional stents were irradiated with 1,000 pulses underwater and then analyzed for particulates, anions and cations liberated from the stent. RESULTS: Photomicroscopy revealed surface etching on a number of stents. Two stent models exhibited multiple strut fractures at the strut joints in both test samples and controls. In no case was a break observed at the site of laser-stent interaction. Breakage frequency was not significantly different between lazed stents and controls. Lazed stents produced a mean of 14 micrograms of sodium and 4 micrograms of iron more than controls. No excess particulates were detected. CONCLUSION: Under model conditions typical of clinical use, excimer laser treatment does not alter stainless-steel stent endurance or liberate clinically significant material from the stent.

Atherectomy, Coronary↗
PubMed1999

Sustained suppression of ischemic complications of coronary intervention by platelet GP IIb/IIIa blockade with abciximab: one-year outcome in the EPILOG trial. Evaluation in PTCA to Improve Long-term Outcome with abciximab GP IIb/IIIa blockade.

BACKGROUND: Blockade of the platelet glycoprotein IIb/IIIa receptor with the monoclonal antibody fragment abciximab was shown in a placebo-controlled randomized trial to reduce the incidence of acute ischemic complications within 30 days among a broad spectrum of patients undergoing percutaneous coronary revascularization. The durability of clinical benefit in this setting has not been established. METHODS AND RESULTS: A total of 2792 patients enrolled in the Evaluation in PTCA to Improve Long-term Outcome with abciximab GP IIb/IIIa blockade (EPILOG) trial were followed with maintenance of double-blinding for 1 year. Patients had been assigned at the time of their index coronary interventional procedure to receive placebo with standard-dose, weight-adjusted heparin (100 U/kg initial bolus), abciximab with standard-dose, weight-adjusted heparin, or abciximab with low-dose, weight-adjusted heparin (70 U/kg initial bolus). The primary outcome was the composite of death, myocardial infarction, or urgent repeat revascularization by 30 days; this composite end point and its individual components were also assessed at 6 months and 1 year. Rates of any repeat revascularization (urgent or elective), target vessel revascularization, and a composite of death, myocardial infarction, or any repeat revascularization were also reported. Follow-up at 1 year was 99% complete for survival status and 97% complete for other end points. By 1 year, the incidence of the primary composite end point was 16.1% in the placebo group, 9.6% in the abciximab with low-dose heparin group (P<0.001), and 9.5% in the abciximab with standard-dose heparin group (P<0.001). Each of the components of this composite end point was reduced to a similar extent. Nonurgent or target vessel repeat revascularization rates were not significantly decreased by abciximab therapy. Mortality rates over 1 year increased with increasing levels of periprocedural creatine kinase MB fraction elevation. CONCLUSIONS: Acute reductions in ischemic events after percutaneous coronary intervention by abciximab are sustained over follow-up to at least 1 year. Early periprocedural myocardial infarctions suppressed by this therapy are associated with long-term mortality rates.

Abciximab↗
PubMed1999

Effect of institutional volume and academic status on outcomes of coronary interventions: the IMPACT-II experience.

BACKGROUND: Rates of morbidity and mortality after interventional procedures are reported to be inversely associated with institutional volume. METHODS: This study assessed both procedural volume and academic status at the 82 US centers that participated in the IMPACT-II trial. Interventional volumes at the sites ranged from 90 to 3300 cases per year. Patients were randomly assigned to a platelet glycoprotein IIb/IIIa inhibitor (eptifibatide) or placebo during procedures done by experienced operators. The primary end point was the composite of death, myocardial infarction, nonelective repeat coronary intervention, or nonelective coronary artery bypass surgery at 30 days, or placement of an intracoronary stent for abrupt closure during the initial procedure. RESULTS: Baseline patient characteristics and median length of stay were similar between the academic and nonacademic centers. In univariable analysis, volume as a continuous variable had a nonlinear relation with the incidence of the composite end point, with better outcomes noted at the highest volume institutions. Academic status did not predict outcome. When added to a predictive model that contained the variables unstable angina, weight, prior coronary artery bypass grafting, heart rate, and platelet count, procedural volume continued to be associated with the composite outcome (P =.04). CONCLUSIONS: We conclude that among hospitals participating in this trial, there is a nonlinear relation between annual interventional volume and outcomes. This relation is complex, involving variations in periprocedural infarction rates and additional, undefined institutional differences (other than academic status) that result in differences in procedural outcome.

Academic Medical Centers↗