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Biomedical subjects

E M Roth

Publications and source records attributed to E M Roth.

At least 19 recordsLinked to original sources
PubMed2001

Coronary perforation during percutaneous coronary intervention in the era of abciximab platelet glycoprotein IIb/IIIa blockade: an algorithm for percutaneous management.

Coronary perforation is an uncommon but potentially life-threatening complication of percutaneous coronary intervention. The use of both atheroablative technologies for coronary intervention and adjunctive platelet glycoprotein blockade pharmacology may increase the incidence of or risk for life-threatening bleeding complications following the occurrence of coronary artery perforation. The interventional database for 6,214 percutaneous coronary interventions performed between January 1995 and June 1999 was analyzed. Hospital charts and cine angiograms for all patients identified in the database as having had coronary perforation were reviewed. Coronary perforation complicated 0.58% of all procedures and was more commonly observed in patients with a history of congestive heart failure and following use of atheroablative interventional technologies (2.8%). There was no association of abciximab therapy with either the incidence of or classification for coronary perforation. Adverse clinical outcomes (death, emergency surgical exploration) were related to the angiographic classification of perforation and were more frequently observed in patients who experienced a class 3 coronary perforation. These data suggest that specific clinical and procedural demographic factors are associated with the occurrence and severity of angiographic coronary perforation. An angiographic perforation class-specific algorithm for treatment of coronary perforation is proposed.

Abciximab↗
PubMed2000

High platelet count in platelet-rich plasma reduces measured platelet inhibition by abciximab but not tirofiban nor eptifibatide glycoprotein IIb/IIIa receptor antagonists.

We evaluated the differential effect of platelet count in platelet-rich plasma (PRP) on the level of ex vivo inhibition of platelet aggregation provided by abciximab, eptifibatide, and tirofiban as part of a randomized, comparative trial of these agents on platelet function in patients with unstable angina pectoris undergoing percutaneous coronary intervention. Platelet count <350 K/microL in PRP reduced measured platelet inhibition by abciximab, but not eptifibatide nor tirofiban. This observation suggests the need for standardized, uniform platelet counts in PRP during future comparisons of the degree of platelet inhibition by these agents.

Abciximab↗
PubMed2000

Abciximab provides cost-effective survival advantage in high-volume interventional practice.

BACKGROUND: Placebo-controlled randomized trials of platelet glycoprotein (GP) IIb/IIIa blockade during percutaneous coronary intervention have demonstrated efficacy of these agents for reducing the risk of periprocedural ischemic events. However, cost-effectiveness of this adjunctive pharmacotherapy has been scrutinized. Extrapolation of cost-efficacy observations from clinical trials to "real world" interventional practice is problematic. METHODS: Consecutive percutaneous coronary interventions (n = 1472) performed by Ohio Heart Health Center operators at The Christ Hospital, Cincinnati, Ohio, in 1997 were analyzed for procedural and long-term (6-month) outcomes and charges. Observations on cost and efficacy (survival) were adjusted for nonrandomized abciximab allocation by means of "propensity scoring" methods. RESULTS: Abciximab therapy was associated with a survival advantage to 6 months after percutaneous coronary intervention. The average reduction in mortality rate at 6 months was 3.4% (unadjusted) and 4.9% when adjusted for nonrandomization. The average charge increment to 6 months was $1512 (unadjusted) and $950 when adjusted for nonrandomization. Patients deriving the greatest reduction in mortality rates also had a reduction in total cardiovascular charges to 6 months. Distinguishing demographics of this population included multivessel coronary intervention, coronary stent deployment, intervention within 1 week of myocardial infarction, and lower left ventricular ejection fraction. The average cost per life-year gained in this study was $2875 for all patients (unadjusted) and $1243 when adjusted for nonrandomization. CONCLUSIONS: Abciximab provides a cost-effective survival advantage in high-volume interventional practice that compares favorably with currently accepted standards. Clinical and procedural demographics associated with increased cost-effectiveness included multivessel coronary intervention, stent deployment, recent (<1 week) myocardial infarction, and impaired left ventricular function.

Abciximab↗
PubMed2000

There is more to monitoring a nuclear power plant than meets the eye.

A fundamental challenge in studying cognitive systems in context is how to move from the specific work setting studied to a more general understanding of distributed cognitive work and how to support it. We present a series of cognitive field studies that illustrate one response to this challenge. Our focus was on how nuclear power plant (NPP) operators monitor plant state during normal operating conditions. We studied operators at two NPPs with different control room interfaces. We identified strong consistencies with respect to factors that made monitoring difficult and the strategies that operators have developed to facilitate monitoring. We found that what makes monitoring difficult is not the need to identify subtle abnormal indications against a quiescent background, but rather the need to identify and pursue relevant findings against a noisy background. Operators devised proactive strategies to make important information more salient or reduce meaningless change, create new information, and off-load some cognitive processing onto the interface. These findings emphasize the active problem-solving nature of monitoring, and highlight the use of strategies for knowledge-driven monitoring and the proactive adaptation of the interface to support monitoring. Potential applications of this research include control room design for process control and alarm systems and user interfaces for complex systems.

Cognitive Science↗
PubMed1999

Time course, magnitude, and consistency of platelet inhibition by abciximab, tirofiban, or eptifibatide in patients with unstable angina pectoris undergoing percutaneous coronary intervention.

Adjunctive platelet glycoprotein IIb/IIIa blockade during percutaneous coronary intervention (PCI) reduces platelet-mediated adverse ischemic outcomes. Although abciximab, eptifibatide, and tirofiban have received U.S. Food and Drug Administration approval for use, these agents differ in their pharmacodynamic profiles. Each of these agents has been compared in randomized trials with placebo for patients undergoing PCI, but no randomized comparative studies of these agents have been performed. We compared ex vivo platelet function by both standard light transmission aggregometry and rapid platelet function assay during and after administration of abciximab, eptifibatide, or tirofiban in approved dose regimens on a randomized basis at the time of PCI in patients with unstable angina pectoris. A reduced intensity of platelet inhibition by light transmission aggregometry was observed for tirofiban compared with either eptifibatide or abciximab. In addition, the 30-minute bolus strategy used for tirofiban was associated with delayed onset of maximal platelet inhibition relative to the initiation of bolus infusion. Whether the trends in platelet function observed in this study will be translated into differences in clinical outcomes awaits definition by larger scale randomized clinical trials comparing these platelet glycoprotein IIb/IIIa inhibitors.

Abciximab↗
PubMed1999

Efficacy of abciximab induced platelet blockade using a rapid point of care assay.

Anciximab provides potent, but variable degrees of platelet inhibition both during the duration of intravenous administration and at 12 hours following therapy. Platelet function was assessed using the PC-RPFA system in 78 patients scheduled for percutaneous coronary revascularization who were administered the standard abciximab weight-adjusted bolus and 12-hour infusion. The PC-RPFA system is a cartridge-based, semiautomated point-of-care whole-blood assay that incorporates fibrinogen-coated polystyrene beads, buffers, and a modified thrombin receptor activating peptide (Isotrap) in lyophilized form. The instrument detects the agglutination rate between the stimulated platelets and the fibrinogen-coated beads, and provides a quantitative digital display in less than 2 minutes. No differences in the level of platelet inhibition were observed in these abciximab-treated patients by diabetic status, gender, smoking, diagnosis (unstable angina, chronic stable angina, recent myocardial infarction), or abciximab treatment status (first time vs. retreatment). Nocorrelation of the PC-RPFA rate of platelet aggregation with clinical demographic factors was observed, with the exception of baseline hematocrit (r2 = 0.4556). The relationship between the PC-RPFA rate of aggregation and hematocrit reflects light absorbance by erythrocytes and is specific to the PC-RPFA system. The absolute rate of platelet aggregation (slope) reported by the PC-RPFA is correlated with percent aggregation, thus making it potentially possible to predict the level of aggregation without reference to a baseline (pretreatment) measure of platelet function. This correlation was closest for patients having <40% baseline aggregation (r2 = 0.55). Thus, PC-RPFA provides a rapid point-of-care assessment of platelet function that could allow for adjustment of abciximab dosing to achieve targeted levels of platelet inhibition. The utility of this device to optimize therapy with platelet glycoprotein IIb/IIIa inhibitors is currently being evaluated.

Abciximab↗
PubMed1992

Cognitive simulation as a tool for cognitive task analysis.

Cognitive simulations are runnable computer programs that represent models of human cognitive activities. We show how one cognitive simulation built as a model of some of the cognitive processes involved in dynamic fault management can be used in conjunction with small-scale empirical data on human performance to uncover the cognitive demands of a task, to identify where intention errors are likely to occur, and to point to improvements in the person-machine system. The simulation, called Cognitive Environment Simulation or CES, has been exercised on several nuclear power plant accident scenarios. Here we report one case to illustrate how a cognitive simulation tool such as CES can be used to clarify the cognitive demands of a problem-solving situation as part of a cognitive task analysis.

Cognition↗