Relation of hyperemic epicardial flow to outcomes among patients with ST-segment elevation myocardial infarction receiving fibrinolytic therapy.

In patients with ST-segment elevation myocardial infarction (STEMI), the restoration of normal epicardial flow following fibrinolytic administration is associated with improved clinical outcomes. The goal of this analysis was to examine the relation between hyperemic flow and outcomes following fibrinolytic administration for STEMI. In Clopidogrel as Adjunctive Reperfusion Therapy-Thrombolysis In Myocardial Infarction 28 (CLARITY-TIMI 28), patients with STEMI (n=3,491) treated with fibrinolytic therapy were scheduled to undergo angiography 48 to 192 hours after randomization. Corrected TIMI frame count (CTFC) and TIMI myocardial perfusion grade (TMPG) were assessed, and their associations with outcomes at 30 days were evaluated. When evaluating initial angiography of the infarct-related artery, there was a nearly linear relation between CTFC and 30-day mortality, with faster flow (lower CTFC) associated with improved outcomes. Conversely, in patients who underwent percutaneous coronary intervention (PCI), very fast flow (CTFC<14) after intervention was associated with worse outcomes. Post-PCI hyperemic flow (CTFC<14) was associated with a higher incidence of mortality (p=0.056), recurrent myocardial infarction (p=0.011), and a composite of death or myocardial infarction (p<0.001) compared with normal flow (CTFC 14 to 28). When post-PCI CTFC was further stratified by TMPG, there was a U-shaped relation between mortality and CTFC in patients with poor myocardial perfusion (TMPG 0 or 1). This relation appeared to be linear in patients with TMPG 2 or 3. In conclusion, in patients who undergo PCI after fibrinolytic therapy for STEMI, hyperemic flow on coronary angiography is associated with an increased incidence of adverse outcomes. Hyperemic flow with associated impaired myocardial perfusion may be a marker of more extensive downstream microembolization.

Impact of saphenous vein graft radiographic markers on clinical events and angiographic parameters.

BACKGROUND: Use of saphenous vein graft (SVG) radiographic markers has been associated with shorter cardiac catheterization procedure times and reduced contrast agent volume for postoperative coronary artery bypass graft (CABG) catheterizations. Use of such markers is varied and often operator-dependent, as the effect of SVG markers has not been fully evaluated. The goal of the present analysis was to evaluate the association of SVG markers with clinical outcomes and graft patency. METHODS: Data were drawn from the Project of Ex-vivo Vein Graft Engineering via Transfection (PREVENT) IV trial of patients undergoing CABG at 107 hospitals across the United States. Repeat angiography was performed within 12 to 18 months after CABG. The SVG markers were used at the discretion of the surgeon and were identified on the follow-up angiogram as any device used to mark the ostium, regardless of shape. RESULTS: The SVG markers were present in 51.2% of evaluable patients (910 of 1,778) and 52.3% of SVGs (2,228 of 4,240). Among patients with totally occluded SVGs (n = 911), visual identification of the SVG was obtained more frequently in those with an SVG marker (90.7% vs 72.1%, p < 0.001). The SVG stenosis 70% or greater at follow-up did not differ by use of markers (25.8% with marker vs 24.4% without marker, p = not significant). These findings were also consistent in ostial lesions (n = 942). Long-term death or myocardial infarction (MI) was similar by use of marker. The perioperative CABG MI was higher in patients with SVG markers (10.1% vs 5.5%, odds ratio adjusted 1.86, p = 0.021). CONCLUSIONS: Saphenous vein graft radiographic markers were associated with higher rates of direct visualization of totally occluded SVGs without an adverse effect on graft patency or long-term clinical outcomes, but the association of SVG markers with increased perioperative CABG MI warrants further examination.

Effects of pretreatment with clopidogrel on nonemergent percutaneous coronary intervention after fibrinolytic administration for ST-segment elevation myocardial infarction: a Clopidogrel as Adjunctive Reperfusion Therapy-Thrombolysis in Myocardial Infarction (CLARITY-TIMI) 28 study.

BACKGROUND: The use of routine nonemergent percutaneous coronary intervention (PCI) among patients with ST-segment elevation myocardial infarction (STEMI) after fibrinolytic therapy is unknown. We sought to evaluate the effect of nonemergent PCI on mortality among patients with STEMI treated with fibrinolytic administration and the consequence of clopidogrel pretreatment on this effect. METHODS: CLARITY-TIMI 28 randomized 3491 patients with STEMI treated with fibrinolytic administration and aspirin to clopidogrel or placebo. All patients were to undergo angiography 48 to 192 hours after randomization. Percutaneous coronary intervention was performed at the discretion of the treating physician. Nonemergent PCI, which was defined as PCI that was not precipitated by recurrent myocardial infarction, was performed in 1781 patients (55.7%). RESULTS: Nonemergent PCI did not affect 30-day mortality (2.0% vs 2.3% among patients who did not undergo PCI). However, nonemergent PCI was associated with lower mortality among patients randomized to clopidogrel (1.3% vs 2.8%, P = .04) but not among those randomized to placebo (2.6% vs 1.7%, P = .25; interaction P = .025). In multivariate modeling, PCI remained associated with lower mortality among patients randomized to clopidogrel (OR 0.34, 95% CI 0.13-0.92, P = .034) but not placebo (OR 1.41, 95% CI 0.63-3.19, P = .40, interaction P = .028). CONCLUSION: Among patients with STEMI treated with fibrinolytic administration and aspirin, nonemergent PCI was associated with lower mortality among patients pretreated with clopidogrel. These results suggest that routine nonemergent PCI is beneficial among such patients, although further confirmatory randomized studies are needed.

Angiographic perfusion score in patients treated with PCI at late angiography following fibrinolytic administration for ST-segment elevation myocardial infarction is associated with morbidity and mortality at 30 days.

BACKGROUND: Among patients with ST-segment elevation myocardial infarction (STEMI), evidence of restoration of both normal epicardial arterial flow and myocardial perfusion early after the administration of fibrinolytic agents has been associated with improved clinical outcomes. In STEMI patients treated with fibrinolytic therapy and scheduled for angiography later during hospital admission, however, the association of later indices of flow and perfusion with clinical outcomes has not been assessed. METHODS: Clopidogrel as Adjunctive Reperfusion Therapy-Thrombolysis in Myocardial Infarction (CLARITY-TIMI) 28 enrolled 3,491 STEMI patients treated with fibrinolytic therapy. Angiography was scheduled 48-192 h (median 84) after randomization. The Angiographic Perfusion Score (APS) (the sum of the TIMI Flow Grade and Myocardial Perfusion Grade before and after percutaneous coronary intervention (PCI), range of 0-12) was assessed in the 1,460 patients treated with PCI at late angiography, and its association with morbidity and mortality at 30 days was examined. RESULTS: Full perfusion, defined as an APS of 10-12, was associated with the lowest mortality (0.8%), while partial perfusion (APS 4-9) (2.3%) and failed perfusion (APS 0-3) (18.0%) were associated with a higher incidence of mortality at 30 days (P < 0.001 for full perfusion vs. partial perfusion, P < 0.0001 for overall trend). In addition, full perfusion was associated with a lower incidence of recurrent myocardial infarction (MI), a composite of death and MI, recurrent myocardial ischemia, ventricular tachyarrhythmia, congestive heart failure and shock (P < 0.05 for all trends). CONCLUSION: Among STEMI patients treated with late PCI following fibrinolytic therapy, higher APS is associated with reduced morbidity and mortality.

Impact of iodinated contrast injections on percent diameter coronary arterial stenosis and implications for trials of intracoronary pharmacotherapies in patients with ST-elevation myocardial infarction.

Administration of fibrinolytic, antiplatelet, and antithrombotic agents by the intracoronary route may disaggregate clot, but the potential role of the mechanical force of the injection itself in decreasing clot burden has not been studied. Patients with ST-segment elevation myocardial infarction who were pretreated in the emergency room (ER) with unfractionated heparin and aspirin in the TITAN-TIMI 34 study were randomized to treatment with eptifibatide in the ER (n = 131) versus after diagnostic catheterization (n = 150). Quantitative coronary angiography was used to assess change in diameter stenosis from time of first contrast injection to injection before percutaneous coronary intervention (PCI) immediately preceding wire placement down the culprit artery in a matching view. Successful perfusion of the myocardium was assessed after PCI by the presence of Thrombolysis In Myocardial Infarction myocardial perfusion grade of 2 or 3. In patients treated with eptifibatide in the ER, there was a 1.3% absolute improvement in diameter stenosis from the first injection to the injection before PCI (p = 0.02), whereas there was no change in diameter stenosis in patients not treated with eptifibatide in the ER (0.0%, p = NS). Each 1% improvement in percent diameter stenosis during diagnostic injections before PCI was strongly correlated with an open muscle after PCI (adjusted odds ratio 1.09, 95% confidence interval 1.02 to 1.16, p = 0.012). In conclusion, the mechanical force of a contrast injection decreases thrombotic burden in patients with ST-segment elevation myocardial infarction pretreated with eptifibatide but not with placebo. Future trials of intracoronary pharmacotherapies should include a control arm in which saline is injected to account for the potential clot disaggregation that occurs as a result of iodinated contrast injections, particularly if the patient has been pretreated with aggressive pharmacotherapy.

Association of prerandomization anticoagulant switching with bleeding in the setting of percutaneous coronary intervention (A REPLACE-2 analysis).

The REPLACE-2 trial of patients who underwent urgent or elective percutaneous coronary intervention (PCI) demonstrated a significantly lower bleeding risk with bivalirudin plus provisional glycoprotein IIb/IIIa inhibitor compared with unfractionated heparin with planned glycoprotein IIb/IIIa inhibitor. The goal of this analysis was to evaluate whether a hazard existed when unfractionated heparin or low-molecular-weight heparin was administered before study medication in the REPLACE-2 trial. The REPLACE-2 trial randomized 6,010 patients undergoing PCI to receive bivalirudin plus provisional glycoprotein IIb/IIIa inhibitor or unfractionated heparin plus planned glycoprotein IIb/IIIa inhibitor. The present study compared bleeding among patients treated with or without antithrombin therapy in the 48 hours before study treatment. Among patients treated with bivalirudin, there was no difference in protocol-defined major or minor bleeding, bleeding according to Thrombolysis In Myocardial Infarction criteria, or noncoronary artery bypass graft blood transfusions between the patients treated with versus without antithrombin therapy (p=NS). However, in patients treated with unfractionated heparin plus planned glycoprotein IIb/IIIa inhibitor, there was a significant increase in the composite of protocol-defined major or minor bleeding and in noncoronary artery bypass graft blood transfusions (p<0.05 for 3-way comparison vs no unfractionated heparin and for 2-way comparisons of no unfractionated heparin vs unfractionated heparin or low-molecular-weight heparin). In conclusion, in patients treated with bivalirudin, pretreatment with antithrombin therapy was not associated with increased bleeding. In contrast, among patients randomized to receive unfractionated heparin and planned glycoprotein IIb/IIIa, pretreatment with antithrombin therapy was associated with increased protocol-defined composite major or minor bleeding and increased need for transfusion.

Diagnostic and prognostic value of ambulatory ECG (Holter) monitoring in patients with coronary heart disease: a review.

Silent ischemia, the most common expression of atherosclerotic heart disease, affects approximately 30-50% of patients during their activities of daily living. The present review provides a comprehensive and practical summary of current knowledge on perioperative myocardial ischemia through MEDLINE searches up to June 2005, using keywords including "silent ischemia," "transient ischemia," and "Holter monitoring." Holter monitoring (i.e., continuous ambulatory ST-segment monitoring) is an effective tool for assessing the frequency and duration of silent transient myocardial ischemia, particularly in patients who are post-acute myocardial infarction (MI), those with acute coronary syndromes (ACS), and in patients in the acute post-operative period. Holter monitoring allows for further risk stratification of patients who have a positive exercise ECG by collecting long-term ECG data on ischemic and arrhythmic events while patients perform routine activities. Both the presence and increased duration of transient ischemia as detected by continuous ST-segment Holter monitoring are associated with increased rates of coronary events and mortality. Holter monitoring may aid in the identification of patients and subgroups of patients with ACS who may derive the greatest benefit from antiplatelet and antithrombotic therapy. Indeed, many ongoing and upcoming trials of pharmacotherapy include ischemia on Holter monitoring as an endpoint.

Usefulness of clopidogrel in abolishing the increased risk of reinfarction associated with higher platelet counts in patients with ST-elevation myocardial infarction (results from CLARITY-TIMI 28).

Previous studies have demonstrated an association between increased baseline platelet counts and poorer clinical and angiographic outcomes in patients with ST-elevation myocardial infarction (STEMI). We hypothesized that antiplatelet therapy would mitigate the effect of high baseline platelet counts on clinical outcomes. Data were obtained from 3,491 patients with STEMI in the CLARITY-TIMI 28 trial. Patients were categorized into 3 groups based on their baseline platelet counts: <200 x 10(3)/microl (group 1), 200 to 300 x 10(3)/microl (group 2), and >300 x 10(3)/microl (group 3). Among placebo-treated patients, reinfarction rates increased in a stepwise fashion as platelet counts increased (3.6%, 5.4%, and 9.0%, respectively, p for trend = 0.0025). When confounders of high platelet counts and correlates of reinfarction were adjusted for in a multivariate model, high platelet counts remained independently associated with increased rates of reinfarction at 30 days in placebo-treated patients; using group 1 as a reference group, multivariate odds ratios were 1.45 (95% confidence interval 0.91 to 2.31, p = 0.119) for patients in group 2 and 1.78 (95% confidence interval 1.03 to 3.08, p = 0.038) for patients in group 3. In contrast, among clopidogrel-treated patients, there was no increase in the risk of reinfarction as the platelet count increased (3.2%, 4.1%, and 3.3%, respectively; p for trend = 0.9073, p for interaction=0.064). In conclusion, among patients with STEMI who are treated with aspirin and a fibrinolytic agent, high platelet counts on presentation are independently associated with increased rates of reinfarction. Clopidogrel therapy abolishes this increase in the risk of reinfarction as platelet counts increase. These data are consistent with a putative role of platelets in reinfarction.

Alpha7 nicotinic acetylcholine receptors targeted by cholinergic developmental neurotoxicants: nicotine and chlorpyrifos.

Alpha7 nicotinic acetylcholine receptors (nAChRs) play a role in axonogenesis, synaptogenesis and synaptic plasticity, and are therefore potential targets for developmental neurotoxicants. We administered nicotine to neonatal rats during discrete periods spanning the onset and peak of axonogenesis/synaptogenesis, focusing on three brain regions with disparate distributions of cell bodies and neural projections: brainstem, forebrain and cerebellum. Nicotine treatment on postnatal days (PN) 1-4 had little or no effect on alpha7 nAChRs but treatment during the second (PN11-14) or third (PN21-24) weeks elicited significant decrements in receptor expression in brainstem and cerebellum, regions containing cell bodies that project to the forebrain. Exposure to chlorpyrifos, a neurotoxicant pesticide that acts partially through cholinergic mechanisms, also elicited deficits in alpha7 nAChRs during the second postnatal week but not the first week. For both nicotine and chlorpyrifos, the effects on alpha7 nAChRs were distinct from those on the alpha4beta2 subtype. Continuous prenatal nicotine exposure, which elicits subsequent, postnatal deficits in axonogenesis and synaptogenesis, also produced delayed-onset changes in alpha7 nAChRs, characterized by reductions in the forebrain and upregulation in the brainstem and cerebellum, a pattern consistent with impaired axonogenesis/synaptogenesis and reactive sprouting. Males were more sensitive to the persistent effects of prenatal nicotine exposure on alpha7 nAChRs, a pattern that mimics neurobehavioral deficits resulting from this treatment. The present findings reinforce the mechanistic involvement of alpha7 nAChRs in the actions of developmental neurotoxicants, and its biomarker potential for neuroteratogens that target neuritic outgrowth.