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Biomedical subjects

Vic Hasselblad

Publications and source records attributed to Vic Hasselblad.

44 records · Page 3Linked to original sources

The failure of orally administered glycoprotein IIb/IIIa inhibitors to prevent recurrent cardiac events.

PURPOSE: Despite the success of intravenous glycoprotein IIb/IIIa antagonists, oral formulations have failed to show benefit and have been associated with increased mortality. To understand these findings, we performed a meta-analysis of results from four phase 3 trials. SUBJECTS AND METHODS: Trials were identified by MEDLINE search; review of abstracts from American College of Cardiology, European Society of Cardiology, and American Heart Association scientific sessions; or querying investigators in the field. Published, phase 3, randomized, placebo-controlled trials involving more than 1000 patients with coronary artery disease that compared an oral glycoprotein IIb/IIIa antagonist with or without background aspirin versus aspirin, and that had a planned follow-up of > or =30 days, were included. Four trials met these criteria. Odds ratios (ORs) and 95% confidence intervals (CIs) were generated from results, and combined using an empirical Bayes random-effects model. RESULTS: Among 33,326 patients, oral glycoprotein IIb/IIIa agents were associated with 31% increased mortality (OR = 1.31; 95% CI: 1.12 to 1.53; P= 0.0001). Results were similar whether the agent was added to (OR = 1.38; 95% CI: 1.15 to 1.67) or substituted for (OR = 1.37; 95% CI: 1.00 to 1.86) aspirin. Ischemic events or sudden death (OR = 1.22; 95% CI: 0.91 to 1.63) were also more common. Among patients with acute coronary syndromes, the incidence of myocardial infarction was increased (OR = 1.16; 95% CI: 1.03 to 1.29). CONCLUSION: Oral glycoprotein IIb/IIIa inhibitor therapy is associated with increased mortality and myocardial infarction. No single explanation for these findings is satisfactory; the problem is likely to be multifactorial.

Administration, Oral↗

First experience with direct factor Xa inhibition in patients with stable coronary disease: a pharmacokinetic and pharmacodynamic evaluation.

BACKGROUND: Thrombin generation is critical to the formation of an arterial thrombus after rupture of an atherosclerotic plaque. In patients with stable coronary disease receiving standard medical therapy, we evaluated the pharmacokinetics, pharmacodynamics, and safety profile of DX-9065a, a novel small-molecule anticoagulant that directly, selectively, and reversibly inhibits factor Xa. METHODS AND RESULTS: In a double-blind trial, 73 patients (median age, 63 years; 29% women) were randomly assigned to receive a fixed-dose intravenous bolus, followed by a 72-hour infusion of placebo or 1 of 4 weight-adjusted regimens of DX-9065a. Plasma samples were collected during infusion and a 24-hour elimination period. Only minor bleeding occurred, predominantly ecchymoses at infusion sites, and its incidence did not differ significantly among the groups, including placebo. Median hemoglobin, platelet count, serum creatinine level, and liver function tests did not change significantly from baseline during infusion or elimination. Significant predictors of pharmacokinetic response included infusion dose and weight. At 60 hours into the DX-9065a infusion, plasma drug levels correlated strongly with anti-factor Xa activity (r=0.97), prothrombin time (r=0.77), and international normalized ratio (r=0.72) but less so with activated partial thromboplastin time (r=0.56; all P<0.001). CONCLUSIONS: This is the first study of a selective, reversible, and direct small-molecule factor Xa inhibitor in patients with stable coronary disease. These data lay the foundation for further investigation of factor Xa inhibitors in the treatment of patients with coronary atherothrombosis.

Adrenergic beta-Antagonists↗

Dissociation between hemodynamic changes and symptom improvement in patients with advanced congestive heart failure.

BACKGROUND: Changes in hemodynamic measures often serve as surrogate end points in efficacy trials for advanced heart failure, although there are few objective data to support this practice. AIMS: We compared changes in hemodynamic variables vs. changes in symptoms of decompensated heart failure in patients enrolled in a randomized trial. METHODS: We studied 201 patients with New York Heart Association (NYHA) class IIIb or IV heart failure and ejection fraction < or = 25% for > or = 3 months. Patients underwent continuous monitoring by pulmonary-artery catheter during inpatient drug administration. We assessed the relations of changes in hemodynamic variables (baseline minus final measure) to changes at 2 weeks in congestive heart failure symptoms, NYHA class, Yale Dyspnea-Fatigue Index (YDFI) score, and distance achieved in a 6-min walk. RESULTS: No hemodynamic measure significantly predicted either symptom score or NYHA classification. Mean pulmonary artery pressure and pulmonary capillary wedge pressure did show some relation to change in YDFI score in univariable, but not multivariable, analysis. No hemodynamic measure correlated significantly with changes in distance achieved in the 6-min walk test. CONCLUSION: We noted no significant association between improved hemodynamics and improved symptoms in patients with advanced heart failure. Other measures may need to be evaluated as surrogate end points in future trials.

Aged↗

Evaluation of platelets in heart failure: is platelet activity related to etiology, functional class, or clinical outcomes?

OBJECTIVES: We sought to determine whether platelet activity in patients with heart failure is related to an ischemic versus nonischemic etiologic condition, clinical disease severity, or adverse clinical outcomes. BACKGROUND: Platelet activity may affect outcome in patients with heart failure. A prospective evaluation of the relation of baseline platelet function to etiologic condition, New York Heart Association (NYHA) class, and clinical outcomes has not been previously reported. METHODS: Ninety-six consecutive outpatients with ambulatory heart failure with an ejection fraction <0.40 and NYHA Class II to IV symptoms who presented to the Duke Heart Failure Clinic and 14 healthy control subjects formed the study groups. Baseline characteristics and blood analyzed for thromboxane (Tx) B2, 6-keto PGF(1alpha), platelet contractile force, adenosine diphosphate/collagen shear-induced closure time, whole blood aggregation and CD41, CD31, CD62p, and CD51/CD61 by flow cytometry were determined. Survival status and hospitalizations were determined in the heart failure patient cohort. RESULTS: The median age of patients was 65 years (22% female, 64% white). An ischemic etiologic condition was present in 61% of patients. The population had mild to moderate heart failure: NYHA class I (1%), II (41%), III (46%), and IV (12.5%) and severe ventricular dysfunction (median ejection fraction = 0.20). There were 39 clinical events (7 deaths, 3 cardiac transplants, 29 other first hospitalizations) in 305 median days of observation. Platelet activity, indicated by whole blood aggregation with 5 micromol adenosine diphosphate (P =.04) and Tx B2 (P =.01), was higher in patients with heart failure. Whole blood aggregation was greater than the 90th percentile in 22% of patients with heart failure versus 7% of control subjects. Platelet function did not differ for any of the markers between the ischemic and nonischemic groups and was not affected by antecedent aspirin. There was no relation of NYHA class or the occurrence of events to platelet activity. CONCLUSION: Platelet activity is heightened in 22% of outpatients with stable heart failure symptoms and is not affected by antecedent aspirin therapy. The degree of platelet activation is similar in ischemic and nonischemic patients with heart failure and is not related to clinical disease severity. Current methods to assess platelet activation do not appear to predict outcome.

Adenosine Diphosphate↗

Role of target vessel size and body surface area on outcomes after percutaneous coronary interventions in women.

BACKGROUND: Women have higher mortality rates than men after coronary angioplasty. Differences in target vessel size may partially account for these differences. We set out to explore the effects of sex, body surface area (BSA), and target coronary vessel size on clinical outcomes after angioplasty. METHODS: Data from 5 interventional trials and 1 registry were pooled for analysis (n = 3982). RESULTS: Compared with men, women undergoing angioplasty were older, had lower weights and BSA, more coronary risk factors, and slightly smaller target coronary vessel size (as assessed by reference vessel diameter). The correlation between target vessel size and BSA was poor (r = 0.13). At 6 months, women had higher mortality rates (1.7% vs 0.8%, P =.03) but similar rates of myocardial infarction and repeat revascularization. On univariate analysis, advanced age, smaller BSA, and female sex were associated with increased mortality, but target vessel size was not. Advanced age was the only significant multivariate predictor of mortality. Target vessel size and diabetes were independent predictors of repeat revascularization. CONCLUSIONS: Women have higher unadjusted 6-month mortality rates after angioplasty, owing largely to their more advanced age at the time of intervention. Smaller target vessel size is associated with increased risk of restenosis and repeat revascularization; however, it does not appear to be a predictor for downstream mortality. As such, the fact that women have smaller vessels does not account for their higher 6-month mortality after coronary angioplasty.

Aged↗

Antibiotic therapy for the treatment of preterm labor: a review of the evidence.

OBJECTIVE: The purpose of this study was to evaluate the evidence regarding antibiotics for the treatment of preterm labor. STUDY DESIGN: Through dual review, we abstracted study design and masking, definitions of preterm labor and pregnancy outcome, patient inclusion/exclusion characteristics, patient demographic characteristics, drug and cointerventions, and numerous birth, maternal, and neonatal outcome measures. We graded the quality of the individual articles and the strength of the evidence for antibiotic benefit. RESULTS: We abstracted data from 14 randomized trials and 1 observational study. Of these studies, 13 trials met the requirements for a meta-analysis. The meta-analysis demonstrated a mixed outcome pattern with small improvements in pregnancy prolongation, estimated gestational age at birth, and birth weight. Data were insufficient to show a beneficial effect on neonatal morbidity or mortality rates. CONCLUSION: Treatment of preterm labor with antibiotic therapy can prolong gestation. The benefits of antibiotics are small, and there is considerable uncertainty about the optimal agent, route, dosage, and duration of therapy.

Anti-Bacterial Agents↗

Benefits of smoking cessation for longevity.

OBJECTIVES: This study determined the life extension obtained from stopping smoking at various ages. METHODS: We estimated the relation between smoking and mortality among 877,243 respondents to the Cancer Prevention Study II. These estimates were applied to the 1990 US census population to examine the longevity benefits of smoking cessation. RESULTS: Life expectancy among smokers who quit at age 35 exceeded that of continuing smokers by 6.9 to 8.5 years for men and 6.1 to 7.7 years for women. Smokers who quit at younger ages realized greater life extensions. However, even those who quit much later in life gained some benefits: among smokers who quit at age 65 years, men gained 1.4 to 2.0 years of life, and women gained 2.7 to 3.7 years. CONCLUSIONS: Stopping smoking as early as possible is important, but cessation at any age provides meaningful life extensions.

Adult↗