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Biomedical subjects

Peter B Berger

Publications and source records attributed to Peter B Berger.

At least 19 recordsLinked to original sources
PubMed2006

Relationship of IgG and IgM autoantibodies to oxidized low density lipoprotein with coronary artery disease and cardiovascular events.

The relationship between autoantibodies to oxidized low density lipoprotein (OxLDL) and coronary artery disease (CAD) remains controversial. IgM and IgG OxLDL autoantibodies to malondialdehyde (MDA)-modified LDL, copper oxidized low density lipoprotein (CuOxLDL), and oxidized cholesterol linoleate (OxCL), as well as apolipoprotein B-100 immune complexes (apoB-ICs), were measured in 504 patients undergoing clinically indicated coronary angiography. Patients were followed for cardiovascular events for a median of 4 years. In univariate analysis, IgM OxLDL autoantibodies and IgM apoB-ICs were inversely associated with the presence of angiographically determined CAD, whereas IgG OxLDL autoantibodies and IgG apoB-ICs were positively associated. In logistic regression analysis, compared with the first quartile, patients in the fourth quartile of IgM OxLDL autoantibodies and apoB-ICs showed a lower probability of angiographically determined CAD (>50% diameter stenosis). Odds ratios and (95% confidence intervals) were as follows: MDA-LDL, 0.51 (0.32-0.82; P = 0.005); CuOxLDL, 0.63 (0.39-1.01; P = 0.05); OxCL, 0.63 (0.39-1.01; P = 0.05); and apoB-IC, 0.55 (0.34-0.88; P = 0.013). These relationships were accentuated in the setting of hypercholesterolemia, with the highest IgM levels showing the lowest risk of CAD for the same level of hypercholesterolemia. Multivariable analysis revealed that neither IgM or IgG OxLDL autoantibodies nor apoB-ICs were independently associated with angiographically determined CAD or cardiovascular events. In conclusion, IgG and IgM OxLDL biomarkers have divergent associations with CAD in univariate analysis but are not independent predictors of CAD or clinical events.

Adult↗
PubMed2006

Age-dependent effect of abciximab in patients with acute coronary syndromes treated with percutaneous coronary interventions.

BACKGROUND: No studies have specifically performed an age-based analysis of the efficacy of abciximab in patients with non-ST-segment elevation acute coronary syndromes undergoing percutaneous coronary intervention (PCI). The aim of the study was to assess whether there are age-dependent differences in the clinical benefit of abciximab in patients with acute coronary syndrome treated with PCI. METHODS AND RESULTS: We performed this retrospective analysis of 2022 patients with acute coronary syndrome enrolled in the Intracoronary Stenting and Antithrombotic Regimen: Rapid Early Action for Coronary Treatment (ISAR-REACT 2) study and randomized to receive abciximab or placebo during a PCI procedure. The incidence of major adverse cardiac events (MACE) during the 30 days after PCI was the primary end point of the study. On the basis of the cutoff age value provided by logistic regression in connection with bootstrap resampling, patients were divided into those younger (n=1220) and older (n=802) than 70 years. Among younger patients, the incidence of MACE was 7.7% in the abciximab group versus 13.3% in the placebo group (relative risk 0.57, 95% confidence interval 0.40 to 0.80, P=0.001). In contrast, no difference was observed among older patients: The incidence of MACE was 10.9% in the abciximab group versus 9.9% in the placebo group (relative risk 1.10, 95% confidence interval 0.72 to 1.69, P=0.65). After adjustment for other variables, including cardiac troponin, there was a significant interaction between age and abciximab (P=0.04) with respect to MACE reduction, with abciximab being more effective in younger patients. CONCLUSIONS: In patients with non-ST-elevation acute coronary syndromes undergoing PCI, the efficacy of abciximab appears to be age-dependent, with greater benefit among younger patients.

Abciximab↗
PubMed2006

Temporal trends in the use of early cardiac catheterization in patients with non-ST-segment elevation acute coronary syndromes (results from CRUSADE).

We evaluated temporal trends in the use of early (<48 hours) catheterization in patients with non-ST-segment elevation acute coronary syndromes with respect to baseline risk features since publication of the American College of Cardiology/American Heart Association guidelines, which include a class IA recommendation for an early invasive strategy for high-risk patients with non-ST-segment elevation acute coronary syndromes. Overall, we found that early catheterization use increased from 53% to 61% during the 3 years after the guidelines were released, but the increased use of early catheterization was highest (11%) in the group that was at lowest risk of predicted mortality, and it was lowest (6%) in the group at highest risk of predicted mortality who would potentially receive the most benefit from an aggressive treatment approach. In conclusion, despite the overall increase in the use of early catheterization, the gap between the use of an early invasive strategy in the highest and lowest risk patients remains large and tends to increase over time.

Acute Disease↗
PubMed2006

Abciximab in patients with acute coronary syndromes undergoing percutaneous coronary intervention after clopidogrel pretreatment: the ISAR-REACT 2 randomized trial.

CONTEXT: No specifically designed studies have addressed the role of the glycoprotein IIb/IIIa inhibitor abciximab in patients with non-ST-segment elevation acute coronary syndromes (ACS) undergoing percutaneous coronary intervention (PCI) after pretreatment with 600 mg of clopidogrel. OBJECTIVE: To assess whether abciximab is associated with clinical benefit in high-risk patients with ACS undergoing PCI after pretreatment with 600 mg of clopidogrel. DESIGN, SETTING, AND PATIENTS: International, multicenter, randomized, double-blind, placebo-controlled study conducted from March 2003 through December 2005, enrolling 2022 patients (mean age, 66 years) with non-ST-segment elevation ACS undergoing PCI. INTERVENTIONS: Patients were assigned to receive either abciximab (0.25 mg/kg of body weight bolus, followed by a 0.125-microg/kg per minute [maximum, 10 microg/min] infusion for 12 hours, plus heparin, 70 U/kg of body weight) or placebo (placebo bolus and infusion of 12 hours, plus heparin bolus, 140 U/kg). All patients received clopidogrel, 600 mg, at least 2 hours prior to the procedure, as well as 500 mg of oral or intravenous aspirin. MAIN OUTCOME MEASURES: The primary end point was a composite of death, myocardial infarction, or urgent target vessel revascularization occurring within 30 days after randomization; secondary end points were rates of in-hospital major and minor bleeding. RESULTS: Of 2022 patients enrolled, 1012 were assigned to abciximab and 1010 to placebo. The primary end point was reached in 90 patients (8.9%) assigned to abciximab vs 120 patients (11.9%) assigned to placebo, a 25% reduction in risk with abciximab (relative risk [RR], 0.75; 95% CI, 0.58-0.97; P = .03). Among patients without an elevated troponin level, there was no difference in the incidence of primary end point events between the abciximab group (23/499 patients [4.6%]) and the placebo group (22/474 patients [4.6%]) (RR, 0.99; 95% CI, 0.56-1.76; P = .98), whereas among patients with an elevated troponin level, the incidence of events was significantly lower in the abciximab group (67/513 patients [13.1%]) compared with the placebo group (98/536 patients [18.3%]), which corresponds to an RR of 0.71 (95% CI, 0.54-0.95; P = .02) (P = .07 for interaction). There were no significant differences between the 2 groups regarding the risk of major and minor bleeding as well as need for transfusion. CONCLUSIONS: Abciximab reduces the risk of adverse events in patients with non-ST-segment elevation ACS undergoing PCI after pretreatment with 600 mg of clopidogrel. The benefits provided by abciximab appear to be confined to patients presenting with an elevated troponin level. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT00133003.

Abciximab↗
PubMed2006

Clopidogrel and aspirin versus aspirin alone for the prevention of atherothrombotic events.

BACKGROUND: Dual antiplatelet therapy with clopidogrel plus low-dose aspirin has not been studied in a broad population of patients at high risk for atherothrombotic events. METHODS: We randomly assigned 15,603 patients with either clinically evident cardiovascular disease or multiple risk factors to receive clopidogrel (75 mg per day) plus low-dose aspirin (75 to 162 mg per day) or placebo plus low-dose aspirin and followed them for a median of 28 months. The primary efficacy end point was a composite of myocardial infarction, stroke, or death from cardiovascular causes. RESULTS: The rate of the primary efficacy end point was 6.8 percent with clopidogrel plus aspirin and 7.3 percent with placebo plus aspirin (relative risk, 0.93; 95 percent confidence interval, 0.83 to 1.05; P=0.22). The respective rate of the principal secondary efficacy end point, which included hospitalizations for ischemic events, was 16.7 percent and 17.9 percent (relative risk, 0.92; 95 percent confidence interval, 0.86 to 0.995; P=0.04), and the rate of severe bleeding was 1.7 percent and 1.3 percent (relative risk, 1.25; 95 percent confidence interval, 0.97 to 1.61 percent; P=0.09). The rate of the primary end point among patients with multiple risk factors was 6.6 percent with clopidogrel and 5.5 percent with placebo (relative risk, 1.2; 95 percent confidence interval, 0.91 to 1.59; P=0.20) and the rate of death from cardiovascular causes also was higher with clopidogrel (3.9 percent vs. 2.2 percent, P=0.01). In the subgroup with clinically evident atherothrombosis, the rate was 6.9 percent with clopidogrel and 7.9 percent with placebo (relative risk, 0.88; 95 percent confidence interval, 0.77 to 0.998; P=0.046). CONCLUSIONS: In this trial, there was a suggestion of benefit with clopidogrel treatment in patients with symptomatic atherothrombosis and a suggestion of harm in patients with multiple risk factors. Overall, clopidogrel plus aspirin was not significantly more effective than aspirin alone in reducing the rate of myocardial infarction, stroke, or death from cardiovascular causes. (ClinicalTrials.gov number, NCT00050817.).

Adult↗
PubMed2006

Optimal timing for the initiation of pre-treatment with 300 mg clopidogrel before percutaneous coronary intervention.

OBJECTIVES: This study sought to determine the optimal timing of a 300-mg clopidogrel loading dose before percutaneous coronary intervention (PCI) in patients enrolled in the Clopidogrel for the Reduction of Events During Observation (CREDO) trial. BACKGROUND: A loading dose of clopidogrel before a PCI has become relatively commonplace, although the data supporting this practice are limited and sometimes conflicting. METHODS: Patients were randomized to receive either 300 mg clopidogrel or a matching placebo administered a minimum of 3 h and a maximum of 24 h before PCI. The primary 28-day combined end point was death, myocardial infarction, or urgent target vessel revascularization. Linear splines were used to summarize the effect of the time of pre-treatment as a continuous variable. RESULTS: A total of 1,762 patients were evaluated. For patients randomized to placebo, there was no relationship between the duration of pre-treatment and the occurrence of the primary end point, whereas longer durations of pre-treatment in patients randomized to clopidogrel were associated with improved outcomes. The event rates diverged maximally at 24 h. The difference in outcomes between placebo and clopidogrel pre-treated patients was not significant until > or =15 h pre-treatment, with a 58.8% (p = 0.028) reduction in the primary end point in patients pre-treated with clopidogrel > or =15 h compared with placebo. CONCLUSIONS: When a 300-mg loading dose of clopidogrel is used, little benefit is obtained compared with just 75 mg at the time of the PCI when the treatment duration is <12 h. In patients pre-treated for longer durations, the optimal duration seems to approach 24 h.

Angioplasty, Balloon, Coronary↗
PubMed2006

Reperfusion of acute myocardial infarction in North Carolina emergency departments (RACE): study design.

Despite the accumulation of almost 2 decades of data in support of rapid reperfusion therapy for ST-segment elevation myocardial infarction (STEMI), the United States healthcare system still faces serious challenges in providing reperfusion to all eligible patients in a timely fashion. American College of Cardiology/American Heart Association guidelines call for systematic interventions aimed at improving both the proportion of patients receiving reperfusion and the timeliness of treatment. We designed a project (RACE) that incorporates standardized protocols and integrated systems for treatment and timely transfer (when appropriate) of patients with STEMI in 5 geographic regions in North Carolina. The RACE project was created by an alliance between national and regional professional societies, a local payer, the pharmaceutical, and healthcare providers, including emergency medical services, emergency medicine, cardiology, and hospital administrations. The main outcomes of interest are rates of reperfusion and time to treatment. Collected data will also provide important insights into barriers to timely reperfusion. The goal of the RACE project is to provide a model for improving the care of patients with STEMI by identifying those features associated with significant improvement, as well as those imposing significant barriers to appropriate therapy.

Angioplasty, Balloon, Coronary↗
PubMed2006

Newer pharmacotherapy in patients undergoing percutaneous coronary interventions: a guide for pharmacists and other health care professionals.

Significant advances in pharmacotherapy for patients undergoing percutaneous coronary intervention (PCI) have occurred during the past decade, including the introduction and approval of new antithrombin and antiplatelet therapies, as well as modifications in dosing, administration, and/or duration of older pharmacotherapy regimens. Also, off-label (i.e., not approved by the United States Food and Drug Administration) use of certain agents has become common. Given the novel nature of these agents and the nuances of therapy, the pharmacist and other health care professionals should play an integral role in collaboration with interventional cardiologists in development of hospital protocols, determination of appropriate agent selection, assessment of patient renal function and hematologic status, dosing, and monitoring for adverse effects. In this guide, the newer antiplatelet and antithrombin drugs that may be used during PCI are reviewed, and recommendations regarding the proper administration of these agents are provided.

Angioplasty, Balloon, Coronary↗
PubMed2006

Therapeutic goals for effective platelet inhibition: a consensus document.

Clopidogrel combined with aspirin is the mainstay of antiplatelet therapy for patients who present with acute coronary syndromes as well as following either bare metal or drug-eluting stent placement. Limitations of clopidogrel therapy include the relatively long time course required to achieve maximal inhibition of platelet aggregation, individual variability in response to its effect, the risk of bleeding during its administration, and the irreversible nature of P2Y12 receptor binding, which leads to a prolonged time course for recovery of platelet function following discontinuation of clopidogrel. Several investigational P2Y12 receptor antagonists have pharmacological properties that may overcome some or all of these limitations. These novel agents such as prasugrel, AZD6140, and cangrelor are in advanced stages of clinical development for potential use in patients with coronary artery disease.

Consensus Statements as Topic↗
PubMed2005

Optimal timing of intervention in non-ST-segment elevation acute coronary syndromes: insights from the CRUSADE (Can Rapid risk stratification of Unstable angina patients Suppress ADverse outcomes with Early implementation of the ACC/AHA guidelines) Registry.

BACKGROUND: Recent studies indicate that a routine invasive approach for patients with unstable angina (UA) and non-ST-segment elevation myocardial infarction (NSTEMI) yields improved outcomes compared with a conservative approach, but the optimal timing of this approach remains open to debate. METHODS AND RESULTS: We used day of hospital presentation as an instrumental variable to study the impact of timing of cardiac catheterization and revascularization therapy on acute outcomes (death, reinfarction, stroke, cardiogenic shock, or congestive heart failure) among patients with UA and NSTEMI. Between January 2001 and September 2003, 56,352 patients with UA or NSTEMI were treated at 310 US hospitals participating in the CRUSADE national quality improvement initiative. Weekend patients were defined as those who presented to the hospital between 5 PM on Friday and 7 AM on Sunday. All other patients were classified as weekday. Weekday patients were similar to weekend patients in terms of demographics, clinical characteristics, and the use of medical therapies in the first 24 hours. Although overall rates of cardiac catheterization and revascularization were similar for the 2 groups, median time to catheterization was significantly longer for weekend than for weekday patients (46.3 versus 23.4 hours, P<0.0001). This delay was not associated with increased in-hospital adverse events, including death (weekend 4.4% versus weekday 4.1%, P=0.23), recurrent MI (2.9% versus 3.0%, P=0.36), or their combination (6.6% versus 6.6%, P=0.86). These findings were not affected by risk adjustment or use of alternative definitions of weekend versus weekday presentation. When weekend presentation was used as the basis for an instrumental variable analysis, we found that catheterization within the first 12 hours of presentation was associated with a nonsignificant trend toward reduced in-hospital mortality (absolute risk reduction 1.9%; 95% CI 6.7% lower to 2.9% higher; P=0.43) that decreased with longer treatment delays. CONCLUSIONS: Although weekend presentation is associated with a delay in invasive management among patients with UA and NSTEMI, in the context of contemporary medical therapy, this does not increase adverse events. Weekend presentation appears to fulfill accepted criteria as an instrumental variable for studying the optimal timing of invasive management for acute coronary syndrome patients. Using weekend status as an instrumental variable, we found no significant benefit to early catheterization, although we could not exclude an important risk reduction, particularly for catheterization within 12 hours of presentation.

Aged↗
PubMed2005

Outcome of patients undergoing balloon angioplasty in the two months prior to noncardiac surgery.

We report on the incidence of adverse cardiac events in 350 patients who underwent noncardiac surgery within 2 months of successful balloon angioplasty (BA) at our institution between 1988 and 2001. Three patients died perioperatively (n = 1) or had myocardial infarction (n = 2) (0.9%, 95% confidence interval [CI] 0.2% to 2.5%), which is a lower incidence than that reported for patients undergoing noncardiac surgery after stenting (3.9% to 32%). One patient died, and 2 had a nonfatal myocardial infarction. All 3 (1.6%, 95% CI 0.3% to 4.6%) were among the 188 patients who underwent surgery within 2 weeks of BA. Repeat target vessel revascularization was performed in 10 patients (2.9%, 95% CI 1.4% to 5.2%): in 3 (1.6%, 95% CI 0.3% to 4.6%) of 188 patients who underwent surgery within 2 weeks of BA and in 7 (5.1%, 95% CI 2.1% to 10.2%) of 138 patients who underwent surgery within 3 to 7 weeks of BA. Therefore, in patients in whom percutaneous coronary revascularization is required before noncardiac surgery, BA appears to be safe, especially in patients who need to undergo surgery early after percutaneous coronary intervention.

Aged↗
PubMed2005

Renal function, concomitant medication use and outcomes following acute coronary syndromes.

BACKGROUND: Chronic kidney disease (CKD) is highly prevalent in patients with cardiovascular disease. We explored the associations of CKD with outcomes using combined data from two large acute coronary syndrome (ACS) trials. We also explored the associations of CKD with prescription patterns for common cardiovascular medications and the association of these prescription patterns with clinical outcomes. METHODS: Patients were stratified by CKD stage using creatinine clearance (CrCl, ml/min) estimated by the modified MDRD equation using baseline core laboratory creatinine measures. Serum creatinine > or =1.5 mg/dl was an exclusion criterion for the SYMPHONY trials. Baseline characteristics and outcomes across CKD categories were compared and Cox proportional hazards regression was used to assess the relationship of renal insufficiency with clinical outcomes after adjusting for previously identified outcome predictors. Interactions between the use of specific medications and calculated CrCl were tested in the final Cox proportional hazards model predicting time to mortality. RESULTS: Of 13 707 patients analysed, 6840 had CKD stage I (CrCl > or =90 ml/min), 5909 stage II (CrCl 60-89 ml/min), 955 stage III (CrCl 30-59 ml/min) and three stage IV (CrCl <30 ml/min). Patients with more advanced CKD (III) were older, more often female, non-smokers and more likely to have co-morbid diseases including diabetes mellitus, hypertension and congestive heart failure. Cardiovascular medications were used less frequently in patients with CKD. Unadjusted survival was poorer in patients with CKD stages > or =II. In adjusted analyses, for those with CrCl < or =91, each 10 ml/min increase in CrCl was associated with a significantly decreased risk of mortality (hazards ratio 0.897, 95% confidence interval 0.815-0.986) (P = 0.024). The interaction between use of angiotensin-converting enzyme (ACE) inhibitors and CrCl was significantly associated with outcomes; the benefit of drug therapy was greater among patients with CKD. CONCLUSIONS: CKD is an independent predictor of risk among ACS patients, and is associated with less frequent use of proven medical therapies. More aggressive use of conventional cardiovascular therapies in patients with CKD and ACS may be warranted.

Aged↗
PubMed2005

Oxidized phospholipids, Lp(a) lipoprotein, and coronary artery disease.

BACKGROUND: Lp(a) lipoprotein binds proinflammatory oxidized phospholipids. We investigated whether levels of oxidized low-density lipoprotein (LDL) measured with use of monoclonal antibody E06 reflect the presence and extent of obstructive coronary artery disease, defined as a stenosis of more than 50 percent of the luminal diameter. METHODS: Levels of oxidized LDL and Lp(a) lipoprotein were measured in a total of 504 patients immediately before coronary angiography. Levels of oxidized LDL are reported as the oxidized phospholipid content per particle of apolipoprotein B-100 (oxidized phospholipid:apo B-100 ratio). RESULTS: Measurements of the oxidized phospholipid:apo B-100 ratio and Lp(a) lipoprotein levels were skewed toward lower values, and the values for the oxidized phospholipid:apo B-100 ratio correlated strongly with those for Lp(a) lipoprotein (r=0.83, P<0.001). In the entire cohort, the oxidized phospholipid:apo B-100 ratio and Lp(a) lipoprotein levels showed a strong and graded association with the presence and extent of coronary artery disease (i.e., the number of vessels with a stenosis of more than 50 percent of the luminal diameter) (P<0.001). Among patients 60 years of age or younger, those in the highest quartiles for the oxidized phospholipid:apo B-100 ratio and Lp(a) lipoprotein levels had odds ratios for coronary artery disease of 3.12 (P<0.001) and 3.64 (P<0.001), respectively, as compared with patients in the lowest quartile. The combined effect of hypercholesterolemia and being in the highest quartiles of the oxidized phospholipid:apo B-100 ratio (odds ratio, 16.8; P<0.001) and Lp(a) lipoprotein levels (odds ratio, 14.2; P<0.001) significantly increased the probability of coronary artery disease among patients 60 years of age or younger. In the entire study group, the association of the oxidized phospholipid:apo B-100 ratio with obstructive coronary artery disease was independent of all clinical and lipid measures except one, Lp(a) lipoprotein. However, among patients 60 years of age or younger, the oxidized phospholipid:apo B-100 ratio remained an independent predictor of coronary artery disease. CONCLUSIONS: Circulating levels of oxidized LDL are strongly associated with angiographically documented coronary artery disease, particularly in patients 60 years of age or younger. These data suggest that the atherogenicity of Lp(a) lipoprotein may be mediated in part by associated proinflammatory oxidized phospholipids.

Adult↗
PubMed2005

Analysis of risk of bleeding complications after different doses of aspirin in 192,036 patients enrolled in 31 randomized controlled trials.

We sought to compare the risk of hemorrhage due to the low (<100 mg), moderate (100 to 200 mg), and high (>200 mg) doses of aspirin (acetylsalicylic acid [ASA]) in 192,036 patients enrolled in 31 clinical trials. Despite substantial differences in the reporting patterns of bleeding complications, low-dose ASA was associated with the lowest risk, and moderate doses caused a relatively high hemorrhagic event rate, especially with regard to minor, gastrointestinal, and total bleeding, and stroke. These findings should be considered when using combination antiplatelets, anticoagulant therapy, or both, with ASA, especially with the daily dose of >100 mg.

Aspirin↗
PubMed2005

One year outcomes with abciximab vs. placebo during percutaneous coronary intervention after pre-treatment with clopidogrel.

AIMS: In the Intracoronary Stenting and Antithrombotic Regimen-Rapid Early Action for Coronary Treatment Trial, the use of abciximab in patients undergoing percutaneous coronary intervention (PCI) after pretreatment with 600 mg clopidogrel for >2 h was associated with no clinically measurable benefit at 30 days. We assessed whether there was any clinical benefit from abciximab at 1 year follow-up. METHODS AND RESULTS: After pre-treatment with 600 mg clopidogrel, a total of 2159 patients undergoing PCI for stable or unstable angina without marked ST-segment shifts or positive biomarkers were randomly assigned to receive abciximab or placebo. The occurrence of the composite endpoint of death, myocardial infarction, or target vessel revascularization was assessed at 1 year after randomization. At 1 year, the composite endpoint occurred in 23.8% of the patients in each group [relative risk (RR), 1.01; 95% confidence interval (CI), 0.85-1.20; P=0.92]. The combined incidence of death and myocardial infarction was 6.0% in the abciximab group and 6.4% in the placebo group (RR, 0.94; 95% CI, 0.67-1.32; P=0.73). The mortality rate was 2.1% in the abciximab group and 2.4% in the placebo group (RR, 0.88; 95% CI, 0.50-1.54; P=0.66). No trend towards clinical benefit was observed with abciximab at 1 year in any subgroup analysed. CONCLUSION: In patients with a low-to-intermediate risk profile undergoing PCI after pre-treatment with a 600 mg clopidogrel for at least 2 h, the use of abciximab offers no additional clinical benefit at 1 year.

Abciximab↗