Part 9: Acute coronary syndromes: 2010 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations

Sex and gender differences in clinical medicine

Sex and gender differences in frequent diseases are more widespread than one may assume. In addition, they have significant yet frequently underestimated consequences on the daily practice of medicine, on outcomes and effects of therapies. Gender medicine is a novel medical discipline that takes into account the effects of sex and gender on the health of women and men. The major goal is to improve health and health care for both, for women as well as for men. We give in this chapter an overview on sex and gender differences in a number of clinical areas, in cardiovascular diseases, pulmonary diseases, gastroenterology and hepatology, in nephrology, autoimmune diseases, endocrinology, hematology, neurology. We discuss the preferential use of male animals in drug development, the underrepresentation of women in early and cardiovascular clinical trials, sex and gender differences in pharmacology, in pharmacokinetics and pharmacodynamics, in management and drug use. Most guidelines do not include even well-known sex and gender differences. European guidelines for the management of cardiovascular diseases in pregnancy have only recently been published. Personalized medicine cannot replace gender-based medicine. Large databases reveal that gender remains an independent risk factor after ethnicity, age, comorbidities, and scored risk factors have been taken into account. Some genetic variants carry a different risk in women and men. The sociocultural dimension of gender integrating lifestyle, environment, stress, and other variables cannot be replaced by a sum of biological parameters. Because of this prominent role of gender, clinical care algorithms must include gender-based assessment.

Coronary versus carotid blood flow and coronary perfusion pressure in a pig model of prolonged cardiac arrest treated by different modes of venoarterial ECMO and intraaortic balloon counterpulsation

INTRODUCTION

Extracorporeal membrane oxygenation (ECMO) is increasingly used in cardiac arrest (CA). Adequacy of carotid and coronary blood flows (CaBF, CoBF) and coronary perfusion pressure (CoPP) in ECMO treated CA is not well established. This study compares femoro-femoral (FF) to femoro-subclavian (FS) ECMO and intraaortic balloon counterpulsation (IABP) contribution based on CaBF, CoBF, CoPP, myocardial and brain oxygenation in experimental CA managed by ECMO.

METHODS

In 11 female pigs (50.3 ± 3.4 kg), CA was randomly treated by FF versus FS ECMO ± IABP. Animals under general anesthesia had undergone 15 minutes of ventricular fibrillation (VF) with ECMO flow of 5 to 10 mL/kg/min simulating low-flow CA followed by continued VF with ECMO flow of 100 mL/kg/min. CaBF and CoBF were measured by a Doppler flow wire, cerebral and peripheral oxygenation by near infrared spectroscopy. CoPP, myocardial oxygen metabolism and resuscitability were determined.

RESULTS

CaBF reached values > 80% of baseline in all regimens. CoBF > 80% was reached only by the FF ECMO, 90.0% (66.1, 98.6). Addition of IABP to FF ECMO decreased CoBF to 60.7% (55.1, 86.2) of baseline, P = 0.004. FS ECMO produced 70.0% (49.1, 113.2) of baseline CoBF, significantly lower than FF, P = 0.039. Addition of IABP to FS did not change the CoBF; however, it provided significantly higher flow, 76.7% (71.9, 111.2) of baseline, compared to FF + IABP, P = 0.026. Both brain and peripheral regional oxygen saturations decreased after induction of CA to 23% (15.0, 32.3) and 34% (23.5, 34.0), respectively, and normalized after ECMO institution. For brain saturations, all regimens reached values exceeding 80% of baseline, none of the comparisons between respective treatment approaches differed significantly. After a decline to 15 mmHg (9.5, 20.8) during CA, CoPP gradually rose with time to 68 mmHg (43.3, 84.0), P = 0 .003, with best recovery on FF ECMO. Resuscitability of the animals was high, both 5 and 60 minutes return of spontaneous circulation occured in eight animals (73%).

CONCLUSIONS

In a pig model of CA, both FF and FS ECMO assure adequate brain perfusion and oxygenation. FF ECMO offers better CoBF than FS ECMO. Addition of IABP to FF ECMO worsens CoBF. FF ECMO, more than FS ECMO, increases CoPP over time.

Identifying patients for early discharge: performance of decision rules among patients with acute chest pain

BACKGROUND

The HEART score and North American Chest Pain Rule (NACPR) are decision rules designed to identify acute chest pain patients for early discharge without stress testing or cardiac imaging. This study compares the clinical utility of these decision rules combined with serial troponin determinations.

METHODS AND RESULTS

A secondary analysis was conducted of 1005 participants in the Myeloperoxidase In the Diagnosis of Acute coronary syndromes Study (MIDAS). MIDAS is a prospective observational cohort of Emergency Department (ED) patients enrolled from 18 US sites with symptoms suggestive of acute coronary syndrome (ACS). The ability to identify participants for early discharge and the sensitivity for ACS at 30 days were compared among an unstructured assessment, NACPR, and HEART score, each combined with troponin measures at 0 and 3h. ACS, defined as cardiac death, acute myocardial infarction, or unstable angina, occurred in 22% of the cohort. The unstructured assessment identified 13.5% (95% CI 11.5-16%) of participants for early discharge with 98% (95% CI 95-99%) sensitivity for ACS. The NACPR identified 4.4% (95% CI 3-6%) for early discharge with 100% (95% CI 98-100%) sensitivity for ACS. The HEART score identified 20% (95% CI 18-23%) for early discharge with 99% (95% CI 97-100%) sensitivity for ACS. The HEART score had a net reclassification improvement of 10% (95% CI 8-12%) versus unstructured assessment and 19% (95% CI 17-21%) versus NACPR.

CONCLUSIONS

The HEART score with 0 and 3 hour serial troponin measures identifies a substantial number of patients for early discharge while maintaining high sensitivity for ACS.

Cocaine intoxication

Cocaine, a natural alkaloid derived from the coca plant, is one of the most commonly abused illicit drugs. Cocaine is commonly abused by inhalation, nasal insufflation, and intravenous injection, resulting in many adverse effects that ensue from local anesthetic, vasoconstrictive, sympathomimetic, psychoactive, and prothrombotic mechanisms. Cocaine can affect all body systems and the clinical presentation may primarily result from organ toxicity. Among the most severe complications are seizures, hemorrhagic and ischemic strokes, myocardial infarction, aortic dissection, rhabdomyolysis, mesenteric ischemia, acute renal injury and multiple organ failure.

The Critical Imperative: Prehospital Management of the Patient with ST-Elevation Myocardial Infarction

Prehospital care is critical to achieve the goal of timely reperfusion in patients with ST-elevation myocardial infarction. Prehospital care is delivered by emergency medical services (EMS) personnel, which include emergency medical dispatchers, first responders, and ambulance response. There is considerable variation in the training and capabilities of the EMS providers in the United States depending on the location (ie, rural vs urban) and local jurisdictions. In this article, the key components of prehospital care of the patient with ST-elevation myocardial infarction and the various levels of training and capabilities of EMS providers are discussed.

Incremental prognostic value of different components of coronary atherosclerotic plaque at cardiac CT angiography beyond coronary calcification in patients with acute chest pain

PURPOSE

To systematically evaluate the incremental predictive value of cardiac computed tomographic (CT) angiography beyond the assessment of coronary artery calcium (CAC) in patients who present with acute chest pain but without evidence of acute coronary syndrome (ACS).

MATERIALS AND METHODS

The human research committee approved this study and waived the need for individual written informed consent. The study was HIPAA compliant. A total of 458 patients (36% male; mean age, 55 years ± 11) with acute chest pain at low to intermediate risk for coronary artery disease underwent coronary calcification assessment with cardiac CT angiography. All patients who did not experience ACS at index hospitalization were followed for instances of a major adverse cardiac event (MACE), such as a myocardial infarct, revascularization, cardiac death, or angina requiring hospitalization. CAC score and cardiac CT angiography were used to derive the presence and extent of atherosclerotic plaque (calcified, noncalcified, or mixed), and obstructive lesions (>50% luminal narrowing) were related to outcomes by using univariate and adjusted Cox proportional hazards models.

RESULTS

Of the 458 patients, 70 (15%) experienced MACE (median follow-up, 13 months). Patients with no plaque at cardiac CT angiography remained free of events during the follow-up period, while 11 (5%) of 215 patients with no CAC had MACE. The extent of plaque was the strongest predictor of MACE independent of traditional risk factors (hazard ratio [HR], 151.77 for four or more segments containing plaque as compared with those containing no plaque; P < .001). Patients with mixed plaque were more likely to experience MACE (HR, 86.96; P = .002) than those with exclusively noncalcified plaque (HR, 58.06; P = .005) or exclusively calcified plaque (HR, 32.94; P = .02).

CONCLUSION

The strong prognostic value of cardiac CT angiography is incremental to its known diagnostic value in patients with acute chest pain without ACS and is independent of traditional risk factors and CAC.

Can the HEART score safely reduce stress testing and cardiac imaging in patients at low risk for major adverse cardiac events?

BACKGROUND

Patients with low-risk chest pain have high utilization of stress testing and cardiac imaging, but low rates of acute coronary syndrome (ACS). The objective of this study was to determine whether the HEART score could safely reduce objective cardiac testing in patients with low-risk chest pain.

METHODS

A cohort of chest pain patients was identified from an emergency department-based observation unit registry. HEART scores were determined using registry data elements and blinded chart review. HEART scores were dichotomized into low (0-3) or high risk (>3). The outcome was major adverse cardiac events (MACE); a composite end point of all-cause mortality, myocardial infarction, or coronary revascularization during the index visit or within 30 days. Sensitivity, specificity, and potential reduction of cardiac testing were calculated.

RESULTS

In a span of 28 months, the registry included 1070 low-risk chest pain patients. MACE occurred in 0.6% (5/904) of patients with low-risk HEART scores compared with 4.2% (7/166) with a high-risk HEART scores (odds ratio = 7.92; 95% confidence interval [95% CI]: 2.48-25.25). A HEART score of >3 was 58% sensitive (95% CI: 32-81%) and 85% specific (95% CI: 83-87%) for MACE. The HEART score missed 5 cases of ACS among 1070 patients (0.5%) and could have reduced cardiac testing by 84.5% (904/1070). Combination of serial troponin >0.065 ng/mL or HEART score >3 resulted in sensitivity of 100% (95% CI: 72-100%), specificity of 83% (95% CI: 81-85%), and potential reduction in cardiac testing of 82% (879/1070).

CONCLUSIONS

If used to guide stress testing and cardiac imaging, the HEART score could substantially reduce cardiac testing in a population with low pretest probability of ACS.

Novel biomarkers in diagnosing cardiac ischemia in the emergency department: a systematic review

BACKGROUND

Novel biomarkers of myocardial ischemia and inflammatory processes have the potential to improve diagnostic accuracy of acute coronary syndrome (ACS) within a shorter time interval after symptom onset.

OBJECTIVE

The objective was to review the recent literature and evaluate the evidence for use of novel biomarkers in diagnosing ACS in patients presenting with chest pain or symptoms suggestive of cardiac ischemia to the emergency department or chest pain unit.

METHODS

A literature search was performed in MEDLINE, EMBASE, Cochrane DSR, ACP Journal Club, DARE, CCTR, CMR, HTA, and NHSEED for studies from 2004 to 2010. We used the inclusion criteria: (1) human subjects, (2) peer-reviewed articles, (3) enrolled patients with ACS, acute myocardial infarction or undifferentiated signs and symptoms suggestive of ACS, and (4) English language or translated manuscripts. Two reviewers conducted a hierarchical selection and assessment using a scale developed by the International Liaison Committee on Resuscitation.

RESULTS

Out of a total 3194 citations, 58 articles evaluating 37 novel biomarkers were included for final review. Forty-one studies did not support the use of their respective biomarkers. Seventeen studies supported the use of 5 biomarkers, particularly when combined with cardiac-specific troponin: heart fatty acid-binding protein, ischemia-modified albumin, B-type natriuretic peptide, copeptin, and matrix metalloproteinase-9.

CONCLUSION

In patients presenting to the emergency department with chest pain or symptoms suggestive of cardiac ischemia, there is inadequate evidence to suggest the routine testing of novel biomarkers in isolation. However, several novel biomarkers have the potential to improve the sensitivity of diagnosing ACS when combined with cardiac-specific troponin.

Management of postcardiac arrest myocardial dysfunction

PURPOSE OF REVIEW

Recent recognition of the importance of postresuscitation care has stimulated interest and new reports concerning therapies for postcardiac arrest myocardial dysfunction. Such cardiac dysfunction after successful resuscitation can be severe and even lethal; however, it is also transient emphasizing the importance of early supportive therapies.

RECENT FINDINGS

The most important strategies for dealing with postresuscitation myocardial dysfunction include a community-formalized effort by individual communities to shorten the time from arrest to restoration of spontaneous circulation, use of therapeutic hypothermia for myocardial preservation, not just cerebral, and early coronary angiography and intervention for all survivors with a high suspicion of a cardiac cause for their arrest. Exciting specific therapies targeted for one or another of the ischemia/reperfusion myocardial injuries associated with cardiac arrest include manipulation of the nitric oxide production in the myocardium, treatment of myocardial microcirculatory dysfunction post resuscitation, inhibition of Na+/H+ exchange, and treatment of calcium flux abnormalities.

SUMMARY

Every community should be striving to provide more timely restoration of pulse and circulation, whereas every medical center receiving patients resuscitated from out-of-hospital cardiac arrest should be providing therapeutic hypothermia for both central nervous system and myocardial preservation. The ability and commitment to provide '24/7' early coronary angiography and percutaneous intervention for all resuscitated victims of sudden cardiac death with a likely cardiac cause for their arrest is also key.

Anti-inflammatory therapeutics for the treatment of atherosclerosis

Atherosclerosis is the primary cause of heart disease and stroke and is thus the underlying pathology of the leading causes of death in the western world. Although risk can be reduced by lowering lipid levels, the equally important contribution of inflammation to the development of cardiovascular disease is not adequately addressed by existing therapies. Here, we summarize the evidence supporting a role for inflammation in the pathogenesis of atherosclerosis, discuss agents that are currently in the clinic and provide a perspective on the challenges faced in the development of drugs that target vascular inflammation.