Original Research Put Into Perspective for the Practicing Clinician
- Factors Associated With Pulseless Electric Activity Versus Ventricular Fibrillation: The Oregon Sudden Unexpected Death Study
- Corticosteroids and Outcome in Children Undergoing Congenital Heart Surgery: Analysis of the Pediatric Health Information Systems Database
- Ticagrelor Versus Clopidogrel in Patients With ST-Elevation Acute Coronary Syndromes Intended for Reperfusion With Primary Percutaneous Coronary Intervention : A Platelet Inhibition and Patient Outcomes (PLATO) Trial Subgroup Analysis
- What Is the Optimal Blood Pressure in Patients After Acute Coronary Syndromes? Relationship of Blood Pressure and Cardiovascular Events in the Pravastatin or Atorvastatin Evaluation and Infection Therapy–Thrombolysis in Myocardial Infarction (PROVE IT-TIMI) 22 Trial
- OMEGA, a Randomized, Placebo-Controlled Trial to Test the Effect of Highly Purified Omega-3 Fatty Acids on Top of Modern Guideline-Adjusted Therapy After Myocardial Infarction
- Ionizing Radiation Exposure to Patients Admitted With Acute Myocardial Infarction in the United States
- Silent Information Regulator 1 Protects the Heart From Ischemia/Reperfusion
- Info & Metrics
Factors Associated With Pulseless Electric Activity Versus Ventricular Fibrillation: The Oregon Sudden Unexpected Death Study
In this population-based study, details of preexisting clinical conditions were combined with emergency medical services data to identify correlates of pulseless electric activity versus ventricular fibrillation and asystole. As expected, cases of cardiac arrest that presented with pulseless electric activity were significantly less likely to survive, and age, black race, female gender, and pulmonary disease were significant correlates of pulseless electric activity. As anticipated, ventricular fibrillation was more likely to be associated with a diagnosis of hyperlipidemia or coronary artery disease. However, there were no differences in the overall disease burden or resuscitation response time that explained occurrence of pulseless electric activity. In addition to reporting specific clinical correlates of pulseless electric activity, this study has identified a novel and significant association between lifetime syncope and future pulseless electric activity that was not explained by a higher prevalence of cardiac conduction system disease on the resting 12-lead ECG. Given the well-established rising prevalence of pulseless electric activity and significantly worse survival outcome compared with ventricular fibrillation, enhancing the mechanistic understanding of pulseless electric activity is a high priority. These findings, particularly the potential link between syncope and pulseless electric activity, are likely to provide a basis for new investigative approaches to evaluate mechanisms of this condition. See p 2116.
Corticosteroids and Outcome in Children Undergoing Congenital Heart Surgery: Analysis of the Pediatric Health Information Systems Database
Children undergoing congenital heart surgery often receive corticosteroids with the aim of reducing the inflammatory response after cardiopulmonary bypass; however, the value of this approach is unclear. Using the Pediatric Health Information Systems Database, we evaluated outcomes associated with corticosteroids in a multicenter cohort of >40 000 children undergoing congenital heart surgery from 2003 to 2008. We were unable to demonstrate a significant benefit associated with corticosteroids and found that corticosteroids may be associated with increased morbidity, particularly in lower-risk patients. These data indicate the need for an adequately powered clinical trial in high-risk patients to evaluate the efficacy and safety of corticosteroids in this population. Further analysis focusing on the potential impact of different dosing regimens and timing of corticosteroid administration relative to surgery may help to inform the design of a future trial. See p 2123.
Ticagrelor Versus Clopidogrel in Patients With ST-Elevation Acute Coronary Syndromes Intended for Reperfusion With Primary Percutaneous Coronary Intervention : A Platelet Inhibition and Patient Outcomes (PLATO) Trial Subgroup Analysis
Ticagrelor, a reversible oral P2Y12-receptor antagonist, provides faster, greater, and more consistent platelet inhibition than clopidogrel. We compared ticagrelor with clopidogrel within the subset of 7544 patients with ST-segment elevation acute myocardial infarction and planned percutaneous coronary intervention from the Platelet Inhibition and Patient Outcomes (PLATO) randomized, double-blind trial. Patients were allocated to ticagrelor 180-mg loading dose followed by 90 mg twice daily or to clopidogrel 300-mg loading dose (with provision for 300 mg clopidogrel at percutaneous coronary intervention) followed by 75 mg daily for 6 to 12 months plus aspirin. The reduction of the primary end point (myocardial infarction, stroke, or cardiovascular death) with ticagrelor versus clopidogrel (10.8% versus 9.4%; hazard ratio [HR] 0.87; 95% confidence interval, 0.75 to 1.01; P=0.07) was consistent with the overall PLATO results. There was no interaction between presentation with ST-segment elevation/left bundle-branch block and randomized treatment (interaction P=0.29). Ticagrelor also reduced several secondary end points, including myocardial infarction alone (HR, 0.80; P=0.03), total mortality (HR, 0.82; P=0.05), and definite stent thrombosis (HR, 0.66; P=0.03). The risk of stroke was higher with ticagrelor than with clopidogrel (1.7% versus 1.0%; HR, 1.63; 95% confidence interval, 1.07 to 2.48; P=0.02). Ticagrelor did not increase the risk of major bleeding (HR, 0.98; P=0.76) compared with clopidogrel (possibly because of the reversibility of the agent). Dyspnea was more frequent with ticagrelor than with clopidogrel but rarely required drug discontinuation (0.5% versus 0.1%; P=0.0004). Given the mortality reduction without increased risk of major bleeding, ticagrelor is an attractive alternative to clopidogrel for patients with ST-segment elevation myocardial infarction and planned percutaneous coronary intervention. See p 2131.
What Is the Optimal Blood Pressure in Patients After Acute Coronary Syndromes? Relationship of Blood Pressure and Cardiovascular Events in the Pravastatin or Atorvastatin Evaluation and Infection Therapy–Thrombolysis in Myocardial Infarction (PROVE IT-TIMI) 22 Trial
Although aggressive blood pressure (BP) control has been advocated in patients with diabetes and more recently in those with acute coronary syndromes, recent trials and observational studies in stable diabetic patients have challenged this concept by finding that more intensive BP lowering was not superior to standard BP lowering. We found in a population of 4162 post–acute coronary syndrome patients that a J- or U-shaped curve existed between BP and the risk of future cardiovascular events, with the lowest event rates in the BP range of approximately 130 to 140/80 to 90 mm Hg. Thus, our findings are consistent with recent studies in stable patients but extend the observation to high-risk post–acute coronary syndrome patients. As such, this study helps provide evidence that clinicians treating hypertension should aim for a systolic BP <140 mm Hg but not <110 mm Hg. See p 2142.
OMEGA, a Randomized, Placebo-Controlled Trial to Test the Effect of Highly Purified Omega-3 Fatty Acids on Top of Modern Guideline-Adjusted Therapy After Myocardial Infarction
The OMEGA study demonstrates that current guideline-adjusted therapy of acute myocardial infarction results in a low rate of mortality, nonfatal reinfarction, or stroke during 1 year of follow-up. This low rate of major clinical events appears to be difficult to improve further with additional therapeutic regimen. In particular, an additional beneficial effect of omega-3 fatty acids on mortality and recurrent nonfatal myocardial infarction during follow-up of patients surviving acute myocardial infarction remains to be proven and is not supported by the OMEGA study. See p 2152.
Ionizing Radiation Exposure to Patients Admitted With Acute Myocardial Infarction in the United States
Over the last decade, there has been a significant growth in the use of imaging studies involving ionizing radiation. Most authorities recommend a conservative strategy when considering tests involving ionizing radiation, in keeping with the “ALARA” (as low as reasonably achievable) principle while still being able to answer the clinical question. In this large retrospective study of >64 000 acute myocardial infarction episodes, we found that during a median 4-day acute myocardial infarction hospitalization, patients were exposed to a median radiation dose of ≈15 mSv, a dose that is 5 times the annual background level and a third of the annual limit for radiation workers. Thus far, the emphasis has focused on the radiation exposure for individual diagnostic tests and their associated doses in isolation. We believe a more important and actionable consideration may be the total cumulative radiation exposure that a patient receives during an episode of care for a given diagnosis. Rather than merely tracking total cumulative radiation exposure longitudinally, this new paradigm lends itself to an improved understanding of the specific predictors of radiation exposure by addressing radiation exposure per episodes of care. In so doing, we hope that ordering healthcare providers might also be encouraged to carefully consider the appropriateness of tests involving radiation and become even more mindful of their potential risks. See p 2160.
Silent Information Regulator 1 Protects the Heart From Ischemia/Reperfusion
Reperfusion injury is a significant health problem in Western countries, but there is no medical treatment to effectively reduce it. We have shown previously that silent information regulator 1 (Sirt1), a class III histone deacetylase and a member of the sirtuin family, inhibits cell death in cardiomyocytes in response to stress and retards aging in the heart. The sirtuin family proteins play an important role in mediating lifespan extension induced by caloric restriction in lower organisms, and stimulation of sirtuins appears to increase lifespan in vertebrates in certain conditions. Because many mechanisms inducing lifespan extension make organisms resistant to stress, we hypothesized that stimulation of sirtuin may also make the heart more resistant to ischemic injury. In this study, we investigated the role of Sirt1 in mediating cardioprotection in a mouse model of ischemia/reperfusion. Although downregulation of endogenous Sirt1 exacerbated myocardial injury, upregulation of Sirt1 attenuated it, in response to ischemia/reperfusion. Sirt1 enhanced nuclear accumulation of FoxO1, a transcription factor regulating antioxidants and cell death/survival mechanisms, which in turn attenuated oxidative stress in the heart. Our results suggest that enhancing the function of Sirt1 is a promising modality to reduce myocardial injury in patients with acute myocardial infarction. See p 2170.
- © 2010 American Heart Association, Inc.
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