Elliott M. Antman

Bio: Elliott M. Antman is an academic researcher from Brigham and Women's Hospital. The author has contributed to research in topics: Myocardial infarction & TIMI. The author has an hindex of 161, co-authored 716 publications receiving 179462 citations. Previous affiliations of Elliott M. Antman include Duke University & Katholieke Universiteit Leuven.

Nifedipine in the Treatment of Cardiovascular Disease

Abstract: Nifedipine, a calcium channel blocking agent, has been shown safe and effective in the treatment of various cardiac disorders. In Prinzmetal's variant angina, nifedipine relieves the acute spasm of a large coronary artery, and thereby reverses the sudden decrease in myocardial oxygen supply. In chronic stable angina, the efficacy of nifedipine stems from an interplay of direct and reflex effects. A decrease in systemic vascular resistance, and thus, myocardial oxygen demand, is considered the most important effect. Although this is partially offset by baroreceptor-mediated reflex increases in blood pressure and heart rate, the net effect is a decrease in myocardial oxygen consumption. The importance of nifedipine-induced increases in coronary blood flow in relieving stable angina remains controversial. Numerous clinical trials in patients with chronic angina have demonstrated that nifedipine increases exercise tolerance by lowering the heart rate-blood pressure product (an approximation of myocardial oxygen consumption). The maximal double product during exercise, however, does not increase, suggesting that the drug does not importantly improve myocardial oxygen supply. Nifedipine may also be of value in the therapy of unstable angina, acute myocardial infarction, and hypertension, as well as in the protection of the myocardium at risk during open heart surgery. However, definite recommendations on the use of the drug for these indications must await results of ongoing randomized studies. The effects of nifedipine are dose-related. Larger doses have been shown more effective than smaller doses, as long as an appropriate blood pressure is maintained. The side effects of nifedipine are mild and related to its vasodilating action.

The efficacy and safety of non-vitamin K antagonist oral anticoagulants in patients with atrial fibrillation and coronary artery disease: A meta-analysis of randomized trials

Abstract: Background:Patients with atrial fibrillation and concomitant coronary artery disease (CAD) are at higher risk for myocardial infarction or cardiovascular death, often require antiplatelet therapy a...

Hemodynamic significance of periprocedural myocardial injury assessed with N-terminal pro-B-type natriuretic peptide after percutaneous coronary intervention in patients with stable and unstable coronary artery disease (from the JUMBO-TIMI 26 trial).

Abstract: The clinical relevance of periprocedural myocardial injury related to percutaneous coronary intervention (PCI) remains controversial. N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) is a sensitive indicator of hemodynamic stress and when increased is associated with higher mortality in patients with acute and chronic ischemic heart disease. We measured the serum level of NT-pro-BNP using the Elecsys 2010 proBNP assay at baseline, 4 to 6 hours, and 12 to 24 hours in 747 patients undergoing elective or urgent PCI and enrolled in the JUMBO-TIMI 26 trial. Periprocedural myocardial infarction (MI) was independently adjudicated and required a new increase in creatine kinase-MB >3 times the upper limit of normal distinct from MI as the indication for PCI. Patients with procedural MI had significantly higher levels of NT-pro-BNP at 12 to 24 hours (405 vs 146 pg/ml, p <0.001). Moreover, the greater increase in NT-pro-BNP in patients with periprocedural MI was independent of each clinical and other procedural correlates of NT-pro-BNP after PCI (p <0.001). In addition, the magnitude of increase in NT-pro-BNP correlated strongly with extent of myocardial injury, including in patients with evidence of injury (creatine kinase-MB 1 to 3 times upper limit of normal) not meeting criteria for MI (p = 0.001) or low-level increase in troponin T (p = 0.001). In conclusion, periprocedural myocardial injury, even at low levels, during PCI is associated with increased hemodynamic stress as measured by increasing NT-pro-BNP. This finding supports the physiologic relevance of procedural MI and the continued effort to define therapies that decrease the risk of this complication.

Measuring inconsistency in meta-analyses

Abstract: Cochrane Reviews have recently started including the quantity I 2 to help readers assess the consistency of the results of studies in meta-analyses. What does this new quantity mean, and why is assessment of heterogeneity so important to clinical practice? Systematic reviews and meta-analyses can provide convincing and reliable evidence relevant to many aspects of medicine and health care.1 Their value is especially clear when the results of the studies they include show clinically important effects of similar magnitude. However, the conclusions are less clear when the included studies have differing results. In an attempt to establish whether studies are consistent, reports of meta-analyses commonly present a statistical test of heterogeneity. The test seeks to determine whether there are genuine differences underlying the results of the studies (heterogeneity), or whether the variation in findings is compatible with chance alone (homogeneity). However, the test is susceptible to the number of trials included in the meta-analysis. We have developed a new quantity, I 2, which we believe gives a better measure of the consistency between trials in a meta-analysis. Assessment of the consistency of effects across studies is an essential part of meta-analysis. Unless we know how consistent the results of studies are, we cannot determine the generalisability of the findings of the meta-analysis. Indeed, several hierarchical systems for grading evidence state that the results of studies must be consistent or homogeneous to obtain the highest grading.2–4 Tests for heterogeneity are commonly used to decide on methods for combining studies and for concluding consistency or inconsistency of findings.5 6 But what does the test achieve in practice, and how should the resulting P values be interpreted? A test for heterogeneity examines the null hypothesis that all studies are evaluating the same effect. The usual test statistic …

The PRISMA Statement for Reporting Systematic Reviews and Meta-Analyses of Studies That Evaluate Health Care Interventions: Explanation and Elaboration

Abstract: Systematic reviews and meta-analyses are essential to summarize evidence relating to efficacy and safety of health care interventions accurately and reliably. The clarity and transparency of these reports, however, is not optimal. Poor reporting of systematic reviews diminishes their value to clinicians, policy makers, and other users. Since the development of the QUOROM (QUality Of Reporting Of Meta-analysis) Statement—a reporting guideline published in 1999—there have been several conceptual, methodological, and practical advances regarding the conduct and reporting of systematic reviews and meta-analyses. Also, reviews of published systematic reviews have found that key information about these studies is often poorly reported. Realizing these issues, an international group that included experienced authors and methodologists developed PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) as an evolution of the original QUOROM guideline for systematic reviews and meta-analyses of evaluations of health care interventions. The PRISMA Statement consists of a 27-item checklist and a four-phase flow diagram. The checklist includes items deemed essential for transparent reporting of a systematic review. In this Explanation and Elaboration document, we explain the meaning and rationale for each checklist item. For each item, we include an example of good reporting and, where possible, references to relevant empirical studies and methodological literature. The PRISMA Statement, this document, and the associated Web site (http://www.prisma-statement.org/) should be helpful resources to improve reporting of systematic reviews and meta-analyses.

The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: the JNC 7 report.

Abstract: "The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure" provides a new guideline for hypertension prevention and management. The following are the key messages(1) In persons older than 50 years, systolic blood pressure (BP) of more than 140 mm Hg is a much more important cardiovascular disease (CVD) risk factor than diastolic BP; (2) The risk of CVD, beginning at 115/75 mm Hg, doubles with each increment of 20/10 mm Hg; individuals who are normotensive at 55 years of age have a 90% lifetime risk for developing hypertension; (3) Individuals with a systolic BP of 120 to 139 mm Hg or a diastolic BP of 80 to 89 mm Hg should be considered as prehypertensive and require health-promoting lifestyle modifications to prevent CVD; (4) Thiazide-type diuretics should be used in drug treatment for most patients with uncomplicated hypertension, either alone or combined with drugs from other classes. Certain high-risk conditions are compelling indications for the initial use of other antihypertensive drug classes (angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, β-blockers, calcium channel blockers); (5) Most patients with hypertension will require 2 or more antihypertensive medications to achieve goal BP (<140/90 mm Hg, or <130/80 mm Hg for patients with diabetes or chronic kidney disease); (6) If BP is more than 20/10 mm Hg above goal BP, consideration should be given to initiating therapy with 2 agents, 1 of which usually should be a thiazide-type diuretic; and (7) The most effective therapy prescribed by the most careful clinician will control hypertension only if patients are motivated. Motivation improves when patients have positive experiences with and trust in the clinician. Empathy builds trust and is a potent motivator. Finally, in presenting these guidelines, the committee recognizes that the responsible physician's judgment remains paramount.

Cochrane Handbook for Systematic Reviews of Interventions

Abstract: The Cochrane Handbook for Systematic Reviews of Interventions is the official document that describes in detail the process of preparing and maintaining Cochrane systematic reviews on the effects of healthcare interventions.