ACC/AHA guidelines for the early management of patients with acute myocardial infarction. A report of the American College of Cardiology/American Heart Association Task Force on Assessment of Diagnostic and Therapeutic Cardiovascular Procedures (subcommittee to develop guidelines for the early management of patients with acute myocardial infarction)

Outcomes of Patients With Takotsubo Syndrome Compared With Type 1 and Type 2 Myocardial Infarction

Background Takotsubo syndrome (TS) and myocardial infarction (MI) share similar clinical and laboratory characteristics but have important differences in causes, demographics, management, and outcomes. Methods and Results In this observational study, the National Inpatient Sample and National Readmission Database were used to identify patients admitted with TS, type 1 MI, or type 2 MI in the United States between October 1, 2017, and December 31, 2019. We compared patients hospitalized with TS, type 1 MI, and type 2 MI with respect to key features and outcomes. Over the 27-month study period, 2 035 055 patients with type 1 MI, 639 075 patients with type 2 MI, and 43 335 patients with TS were identified. Cardiac arrest, ventricular fibrillation, and ventricular tachycardia were more prevalent in type 1 MI (4.02%, 3.2%, and 7.2%, respectively) compared with both type 2 MI (2.8%, 0.8%, and 5.4% respectively) and TS (2.7%, 1.8%, and 5.3%, respectively). Risk of mortality was lower in TS compared with both type 1 MI (3.3% versus 7.9%; adjusted odds ratio [OR], 0.3; P<0.001) and type 2 MI (3.3% versus 8.2%; adjusted OR, 0.3; P<0.001). Mortality rate (OR, 1.2; P<0.001) and cardiac-cause 30-day readmission rate (adjusted OR, 1.7; P<0.001) were higher in type 1 MI than in type 2 MI. Conclusions Patients with type 1 MI had the highest rates of in-hospital mortality and cardiac-cause 30-day readmission. Risk of all-cause 30-day readmission was highest in patients with type 2 MI. The risk of ventricular arrhythmias in patients with TS is lower than in patients with type 1 MI but higher than in patients with type 2 MI.

Mechanical complications in STEMI: prevalence and mortality trends in the primary PCI era. The Ruti-STEMI registry

INTRODUCTION AND OBJECTIVES

Mechanical complications confer a dreadful prognosis in ST-elevation myocardial infarction (STEMI). Their prevalence and prognosis are not well-defined in the current era of primary percutaneous coronary intervention (pPCI) reperfusion networks. We aimed to analyze prevalence and mortality trends of post-STEMI mechanical complications over 2 decades, before and after the establishment of pPCI networks.

METHODS

Prospective, consecutive registry of STEMI patients within a region of 850 000 inhabitants over 2 decades: a pre-pPCI period (1990-2000) and a pPCI period (2007-2017). We analyzed the prevalence of mechanical complications, including ventricular septal rupture, papillary muscle rupture, and free wall rupture (FWR). Twenty eight-day and 1-year mortality trends were compared between the 2 studied decades.

RESULTS

A total of 6033 STEMI patients were included (pre-pPCI period, n=2250; pPCI period, n=3783). Reperfusion was supported by thrombolysis in the pre-pPCI period (99.1%) and by pPCI in in the pPCI period (95.7%). Mechanical complications developed in 135 patients (2.2%): ventricular septal rupture in 38 patients, papillary muscle rupture in 24, and FWR in 73 patients. FWR showed a relative reduction of 60% in the pPCI period (0.8% vs 2.0%, P<.001), without significant interperiod changes in the other mechanical complications. After multivariate adjustment, FWR remained higher in the pre-pPCI period (OR, 1.93; 95%CI, 1.10-3.41; P=.023). At 28 days and 1 year, mortality showed no significant changes in all the mechanical complications studied.

CONCLUSIONS

The establishment of regional pPCI networks has modified the landscape of mechanical complications in STEMI. FWR is less frequent in the pPCI era, likely due to reduced transmural infarcts.

Nitroglycerin Use in the Emergency Department: Current Perspectives

Nitroglycerin, a fast-acting vasodilator, is commonly used as a first-line agent for angina in the emergency department and to manage chest pain due to acute coronary syndromes. It is also a treatment option for other disease states such as acute heart failure, pulmonary edema, and aortic dissection. Nitroglycerin is converted to nitric oxide, a potent vasodilator, in the body, leading to venodilation at lower dosages and arteriodilation at higher dosages that results in both preload and afterload reduction, respectively. Although nitroglycerin has historically been administered as a sublingual tablet and/or spray, it is often given intravenously in the emergency department as this enables titration to effect with predictable pharmacokinetics. In this review article, we outline the indications, mechanism of action, contraindications, and adverse effects of nitroglycerin as well as review relevant literature and make general recommendations regarding the use of nitroglycerin in the emergency department.

99th Percentile Upper-Reference Limit of Cardiac Troponin and the Diagnosis of Acute Myocardial Infarction

BACKGROUND

Concerns exist regarding how the 99th percentile upper reference limit (URL) of cardiac troponin (cTn) is determined and whether it should be derived from normal healthy individuals.

CONTENT

The 99th percentile URL of cTn is an important criterion to standardize the diagnosis of myocardial infarction (MI) for clinical, research, and regulatory purposes. Statistical heterogeneity in its calculation exists but recommendations have been proposed. Some negativity has resulted from the fact that with some high-sensitivity (hs) cTn assays, a greater number of increases above the 99th percentile are observed when transitioning from a contemporary assay. Increases reflect acute or chronic myocardial injury and provide valuable diagnostic and prognostic information. The etiology of increases can sometimes be difficult to determine, making a specific treatment approach challenging. For those reasons, some advocate higher cutoff concentrations. This approach can contribute to missed diagnoses. Contrary to claims, neither clinical or laboratory guidelines have shifted away from the 99th percentile. To support the diagnosis of acute MI, the 99th percentile URL remains the best-established approach given the absence of cTn assay standardization. Importantly, risk stratification algorithms using hs-cTn assays predict the possibility of MI diagnoses established using the 99th percentile.

SUMMARY

The 99th percentile of cTn remains the best-established criterion for the diagnosis of acute MI. While not perfect, it is analytically and clinically evidence-based. Until there are robust data to suggest some other approach, staying with the 99th percentile, a threshold that has served the field well for the past 20 years, appears prudent.

Efficacy of Long-Term Oral Beta-Blocker Therapy in Patients Who Underwent Percutaneous Coronary Intervention for ST-Segment Elevation Myocardial Infarction With Preserved Left Ventricular Ejection Fraction: A Systematic Review and Meta-analysis

ABSTRACT

After the results of the first multicenter, prospective randomized clinical trial (RCT) evaluating long-term efficacy of oral beta-blockers in patients with preserved left ventricular ejection fraction (LVEF) after ST elevation myocardial infarction (STEMI), we decided to conduct an updated systematic review and meta-analysis to evaluate the long-term efficacy of oral beta-blocker use in patients with preserved LVEF who underwent percutaneous coronary intervention (PCI) for STEMI. A time-limited search from January 1, 1999, to April 16, 2020, on PubMed and EMBASE was conducted on April 16, 2020, for observational studies and clinical trials evaluating the efficacy of long-term oral beta-blockers in patients with preserved LVEF after STEMI treated with PCI. The comparative outcomes between beta-blockers and non-beta-blockers were assessed by pooling weighted odds ratio (OR) with 95% confidence interval (CI) using random-effects model. The outcomes of interest were all-cause mortality and major adverse cardiac event (MACE). Twelve studies (11 observational and 1 RCT) comprising 32,108 patients (19,740 on beta-blocker therapy and 12,368 without beta-blocker therapy) were included. Of which, 75% percent were male (mean age of 64 years: 63.87 ± 3.01 years on beta-blocker therapy and 64.76 ± 3.02 years on non-beta-blocker therapy; P = 0.129) with a follow-up of up to 4.7 years. Unadjusted all-cause mortality [OR = 0.58 (95% CI: 0.42-0.79)] and adjusted all-cause mortality [OR = 0.64 (95% CI: 0.48-0.87)] were significantly lower in patients on the long-term beta-blocker therapy group. However, unadjusted MACE [OR = 0.87 (95% CI: 0.70-1.08)] was not reduced with beta-blocker therapy in these patients. Patients with preserved LVEF after STEMI treated with PCI on long-term oral beta-blocker therapy have a significant reduction in risk of all-cause mortality, without an effect on MACE rates. The only RCT included showed neutral effect, so results of ongoing RCTs are anticipated. Considering that the only high-quality data (RCT) suggest a neutral effect, one should be cautious in interpreting the conclusion.

Trends in Short- and Long-Term ST-Segment-Elevation Myocardial Infarction Prognosis Over 3 Decades: A Mediterranean Population-Based ST-Segment-Elevation Myocardial Infarction Registry

Background Coronary artery disease remains a major cause of death despite better outcomes of ST-segment-elevation myocardial infarction (STEMI). We aimed to analyze data from the Ruti-STEMI registry of in-hospital, 28-day, and 1-year events in patients with STEMI over the past 3 decades in Catalonia, Spain, to assess trends in STEMI prognosis. Methods and Results Between February 1989 and December 2017, a total of 7589 patients with STEMI were admitted consecutively. Patients were grouped into 5 periods: 1989 to 1994 (period 1), 1995 to 1999 (period 2), 2000 to 2004 (period 3), 2005 to 2009 (period 4), and 2010 to 2017 (period 5). We used Cox regression to compare 28-day and 1-year STEMI mortality and in-hospital complication trends across these periods. Mean patient age was 61.6±12.6 years, and 79.3% were men. The 28-day all-cause mortality declined from period 1 to period 5 (10.4% versus 6.0%; P<0.001), with a 40% reduction after multivariable adjustment (hazard ratio [HR], 0.6; 95% CI, 0.46-0.80; P<0.001). One-year all-cause mortality declined from period 1 to period 5 (11.7% versus 9.0%; P=0.001), with a 24% reduction after multivariable adjustment (HR, 0.76; 95% CI, 0.60-0.98; P=0.036). A significant temporal reduction was observed for in-hospital complications including postinfarct angina (-78%), ventricular tachycardia (-57%), right ventricular dysfunction (-48%), atrioventricular block (-45%), pericarditis (-63%), and free wall rupture (-53%). Primary ventricular fibrillation showed no significant downslope trend. Conclusions In-hospital STEMI complications and 28-day and 1-year mortality rates have dropped markedly in the past 30 years. Reducing ischemia-driven primary ventricular fibrillation remains a major challenge.

Short- and Long-Term Mortality Trends in STEMI-Cardiogenic Shock over Three Decades (1989-2018): The Ruti-STEMI-Shock Registry

Aims: Cardiogenic shock (CS) is an ominous complication of ST-elevation myocardial infarction (STEMI), despite the recent widespread use of reperfusion and invasive management. The Ruti-STEMI-Shock registry analysed the prevalence of and 30-day and 1-year mortality rates in ST-elevation myocardial infarction (STEMI) complicated by CS (STEMI-CS) over the last three decades. Methods and Results: From February 1989 to December 2018, 493 STEMI-CS patients were consecutively admitted in a well-defined geographical area of ~850,000 inhabitants. Patients were classified into six five-year periods based on their year of admission. STEMI-CS mortality trends were analysed at 30 days and 1 year across the six strata. Cox regression analyses were performed for comparisons. Mean age was 67.5 ± 11.7 years; 69.4% were men. STEMI-CS prevalence did not decline from period 1 to 6 (7.1 vs. 6.2%, p = 0.218). Reperfusion therapy increased from 22.5% in 1989–1993 to 85.4% in 2014–2018. Thirty-day all-cause mortality declined from period 1 to 6 (65% vs. 50.5%, p < 0.001), with a 9% reduction after multivariable adjustment (HR: 0.91; 95% CI: 0.84–0.99; p = 0.024). One-year all-cause mortality declined from period 1 to 6 (67.5% vs. 57.3%, p = 0.001), with an 8% reduction after multivariable adjustment (HR: 0.92; 95% CI: 0.85–0.99; p = 0.030). Short- and long-term mortality trends in patients aged ≥ 75 years remained ~75%. Conclusions: Short- and long-term STEMI-CS-related mortality declined over the last 30 years, to ~50% of all patients. We have failed to achieve any mortality benefit in STEMI-CS patients over 75 years of age.

Effects of early intravenous low-dose of metoprolol on cardiac sympathetic activities and electrophysiological properties in myocardial infarction heart

This study observed the effects of early intravenous low-doses of metoprolol on cardiac sympathetic activities and electrophysiological properties in myocardial infarction (MI) dogs. Thirty two mongrel dogs with the first diagonal branch of the left anterior descending coronary artery ligated were randomly divided into three groups: The low-dose group was given metoprolol 0.6 mg/kg immediately by intravenous injection (n=12); the target-dose group was given metoprolol 1.6 mg/kg (n=12), and the control group was injected with normal saline at the same dose of the target-dose group (n=8). Norepinephrine (NE) and epinephrine (E) levels in the coronary sinus (CS) blood as well as the ventricular effective refractory period (ERP) were all measured during the experiments. We found that NE and E concentrations in the three groups were all increased compared with the previous measurement before ligation. ERP values after MI were significantly decreased in all three groups compared with the first measurements. The three groups all exhibited uneven shortness of ERP among different regions, with significant shortness in infarcted area. Furthermore, there was no difference between the low and target-dose of metoprolol in the reduction of regional ERP, and the same effect was also observed in induced arrhythmias. In conclusion, a lower dose of metoprolol performed similarly as target-dose in reducing the catecholamine concentrations in dogs with MI. Our study demonstrated that a lower dose of metoprolol may be reasonable compared with the target-dose in β-blocker therapy due to similar effect and lower toxicity.

Through the Decades: β-Blocker Use and Outcomes in Acute Coronary Syndromes

Beta-adrenergic receptor antagonists, or β-blockers, have been a cornerstone of treatment in patients with acute coronary syndromes (ACS) for more than 4 decades. First studied in the 1960s, β-blockers in ACS have been shown to decrease the risk of death, recurrent ischemic events, and arrhythmias by reducing catecholamine-mediated effects and reducing myocardial oxygen demand. Through the decades, the β-blocker of choice, timing of initiation, duration of therapy, and dosing have evolved considerably. Despite having clear benefits in certain patient populations (eg, patients with systolic dysfunction who are hemodynamically stable), the benefit of β-blockers in other populations (ie, in patients at low risk for complications receiving modern revascularization therapies and optimal medical management) remains unclear. This article provides a review of the landmark clinical trials of β-blockers in ACS and highlights the chronology and evolution of guideline recommendations through the decades.

Ten-Year (2001-2011) Trends in the Incidence Rates and Short-Term Outcomes of Early Versus Late Onset Cardiogenic Shock After Hospitalization for Acute Myocardial Infarction

Background

Cardiogenic shock (CS) is a serious complication of acute myocardial infarction, and the time of onset of CS has a potential role in influencing its prognosis. Limited contemporary data exist on this complication, however, especially from a population‐based perspective. Our study objectives were to describe decade‐long trends in the incidence, in‐hospital mortality, and factors associated with the development of CS in 3 temporal contexts: (1) before hospital arrival for acute myocardial infarction (prehospital CS); (2) within 24 hours of hospitalization (early CS); and (3) ≥24 hours after hospitalization (late CS).

Methods and Results

The study population consisted of 5782 patients with an acute myocardial infarction who were admitted to all 11 hospitals in central Massachusetts on a biennial basis between 2001 and 2011. The overall proportion of patients who developed CS was 5.2%. The proportion of patients with prehospital CS (1.6%) and late CS (1.5%) remained stable over time, whereas the proportion of patients with early CS declined from 2.2% in 2001–2003 to 1.2% in 2009–2011. In‐hospital mortality for prehospital CS increased from 38.9% in 2001–2003 to 53.6% in 2009–2011, whereas in‐hospital mortality for early and late CS decreased over time (35.9% and 64.7% in 2001–2003 to 15.8% and 39.1% in 2009–2011, respectively).

Conclusions

Development of prehospital and in‐hospital CS was associated with poor short‐term survival and the in‐hospital death rates among those with prehospital CS increased over time. Interventions focused on preventing or treating prehospital and late CS are needed to improve in‐hospital survival after acute myocardial infarction.

Glycated hemoglobin level is an independent predictor of major adverse cardiac events after nonfatal acute myocardial infarction in nondiabetic patients: A retrospective observational study

The effect of glycemic control on the prognosis of nondiabetic patients after acute myocardial infarction (AMI) remains uncertain. We investigated whether glycated hemoglobin (HbA1c) is associated with adverse outcomes after AMI in nondiabetic patients. In this observational study, we enrolled nondiabetic patients with AMI in the emergency department of 2 medical centers from January 2011 to September 2014. All patients received primary percutaneous coronary intervention and were divided into 4 groups according to the interquartile range of average HbA1c level (Group I, ≤5.6%; Group II, 5.6%-5.8%; Group III, 5.8%-6.0%; and Group IV, >6.0%). Multivariate logistic analysis was performed to estimate the correlation of HbA1c with major adverse cardiac events (MACEs) after AMI. In total, 267 eligible patients were enrolled; 48 patients (18%) developed MACEs within a median follow-up of 178 days. Univariate analysis showed HbA1c > 6.0%, with a higher risk of MACEs in Group IV than in Group I (odds ratio [OR]: 2.733; 95% confidence interval [CI]: 1.123-6.651 vs OR: 1.511; 95% CI: 0.595-3.835). Multivariate analysis revealed an approximately 3.8 times higher risk of MACEs in Group IV than in Group I (OR: 3.769; 95% CI: 1.30-10.86). The HbA1 level is a significant predictor of MACEs after AMI in nondiabetic patients.

Scientific Rationale for the Inclusion and Exclusion Criteria for Intravenous Alteplase in Acute Ischemic Stroke

Purpose—

To critically review and evaluate the science behind individual eligibility criteria (indication/inclusion and contraindications/exclusion criteria) for intravenous recombinant tissue-type plasminogen activator (alteplase) treatment in acute ischemic stroke. This will allow us to better inform stroke providers of quantitative and qualitative risks associated with alteplase administration under selected commonly and uncommonly encountered clinical circumstances and to identify future research priorities concerning these eligibility criteria, which could potentially expand the safe and judicious use of alteplase and improve outcomes after stroke.

Methods—

Writing group members were nominated by the committee chair on the basis of their previous work in relevant topic areas and were approved by the American Heart Association Stroke Council’s Scientific Statement Oversight Committee and the American Heart Association’s Manuscript Oversight Committee. The writers used systematic literature reviews, references to published clinical and epidemiology studies, morbidity and mortality reports, clinical and public health guidelines, authoritative statements, personal files, and expert opinion to summarize existing evidence and to indicate gaps in current knowledge and, when appropriate, formulated recommendations using standard American Heart Association criteria. All members of the writing group had the opportunity to comment on and approved the final version of this document. The document underwent extensive American Heart Association internal peer review, Stroke Council Leadership review, and Scientific Statements Oversight Committee review before consideration and approval by the American Heart Association Science Advisory and Coordinating Committee.

Results—

After a review of the current literature, it was clearly evident that the levels of evidence supporting individual exclusion criteria for intravenous alteplase vary widely. Several exclusionary criteria have already undergone extensive scientific study such as the clear benefit of alteplase treatment in elderly stroke patients, those with severe stroke, those with diabetes mellitus and hyperglycemia, and those with minor early ischemic changes evident on computed tomography. Some exclusions such as recent intracranial surgery are likely based on common sense and sound judgment and are unlikely to ever be subjected to a randomized, clinical trial to evaluate safety. Most other contraindications or warnings range somewhere in between. However, the differential impact of each exclusion criterion varies not only with the evidence base behind it but also with the frequency of the exclusion within the stroke population, the probability of coexistence of multiple exclusion factors in a single patient, and the variation in practice among treating clinicians.

Reperfusion therapy for acute myocardial infarction: Concepts and controversies from inception to acceptance

More than 20 years of misconceptions derailed acceptance of reperfusion therapy for acute myocardial infarction (AMI). Cardiologists abandoned reperfusion for AMI using fibrinolytic therapy, explored in 1958, because they no longer attributed myocardial infarction to coronary thrombosis. Emergent aortocoronary bypass surgery, pioneered in 1968, remained controversial because of the misconception that hemorrhage into reperfused myocardium would result in infarct extension. Attempts to limit infarct size by pharmacotherapy without reperfusion dominated research in the 1970s. Myocardial necrosis was assumed to progress slowly, in a lateral direction. At least 18 hours was believed to be available for myocardial salvage. Afterload reduction and improvement of the microcirculation, but not reperfusion, were thought to provide the benefit of streptokinase therapy. Finally, coronary vasospasm was hypothesized to be the central mechanism in the pathogenesis of AMI. These misconceptions unraveled in the late 1970s. Myocardial necrosis was shown to progress in a transmural direction, as a "wave front," beginning with the subendocardium. Reperfusion within 6 hours salvaged a subepicardial ischemic zone in experimental animals. Acute angiography provided in vivo evidence of the high incidence of total coronary occlusion in the first hours of AMI. In 1978, early reperfusion by transluminal recanalization was shown to be feasible. The pathogenetic role of coronary thrombosis was definitively established in 1979 by demonstrating that intracoronary streptokinase rapidly restored flow in occluded infarct-related arteries, in contrast to intracoronary nitroglycerine which rarely did. The modern reperfusion era had dawned.

Effectiveness of regionalized systems for stroke and myocardial infarction

BACKGROUND

Acute ischemic stroke (AIS) and ST-segment elevation myocardial infarction (STEMI) are ischemic emergencies. Guidelines recommend care delivery within formally regionalized systems of care at designated centers, with bypass of nearby centers of lesser or no designation. We review the evidence of the effectiveness of regionalized systems in AIS and STEMI.

METHODS

Literature was searched using terms corresponding to designation of AIS and STEMI systems and from 2010 to the present. Inclusion criteria included report of an outcome on any dependent variable mentioned in the rationale for regionalization in the guidelines and an independent variable comparing care to a non- or pre-regionalized system. Designation was defined in the AIS case as certification by the Joint Commission as either a primary (PSC) or comprehensive (CSC) stroke center. In the STEMI case, the search was conducted linking "regionalization" and "myocardial infarction" or citation as a model system by any American Heart Association statement.

RESULTS

For AIS, 17 publications met these criteria and were selected for review. In the STEMI case, four publications met these criteria; the search was therefore expanded by relaxing the criteria to include any historical or anecdotal comparison to a pre- or nonregionalized state. The final yield was nine papers from six systems.

CONCLUSION

Although regionalized care results in enhanced process and reduced unadjusted rates of disparity in access and adverse outcomes, these differences tend to become nonsignificant when adjusted for delayed presentation and hospital arrival by means other than emergency medical services. The benefits of regionalized care occur along with a temporal trend of improvement due to uptake of quality initiatives and guideline recommendations by all systems regardless of designation. Further research is justified with a randomized registry or cluster randomized design to support or refute recommendations that regionalization should be the standard of care.

Adherence to evidence-based secondary prevention pharmacotherapy in patients after an acute coronary syndrome: A systematic review

OBJECTIVE

To synthesize current evidence on medication adherence rates and associated risk factors in patients after an acute coronary syndrome (ACS).

METHODS

A systematic review was conducted. Five electronic databases and article bibliographies were searched for publications from 1990 to 2013 which assessed adherence to secondary prevention pharmacotherapy in adults after hospital discharge for an ACS. Identified studies were screened using pre-defined criteria for eligibility. A standardized form was used for data abstraction. Methodological quality was assessed using modified criteria for quantitative studies.

RESULTS

Sixteen studies met our inclusion criteria. Post-discharge medication adherence rates at 1-year ranged between 54% and 86%. There were no consistent predictors of non-adherence across all cardiac medication classes examined.

CONCLUSIONS

Adherence to secondary prevention pharmacotherapy was suboptimal in patients after hospital discharge for an ACS. Risk factors associated with non-adherence were examined in a limited number of studies, and the associations varied between these investigations.

Challenges in assessing the process-outcome link in practice

The expanded use of clinical process-of-care measures to assess the quality of health care in the context of public reporting and pay-for-performance applications has led to a desire to demonstrate the value of such efforts in terms of improved patient outcomes. The inability to observe associations between improved delivery of clinical processes and improved clinical outcomes in practice has raised concerns about the value of holding providers accountable for delivery of clinical processes of care. Analyses that attempt to investigate this relationship are fraught with many challenges, including selection of an appropriate outcome, the proximity of the outcome to the receipt of the clinical process, limited power to detect an effect, small expected effect sizes in practice, potential bias due to unmeasured confounding factors, and difficulties due to changes in measure specification over time. To avoid potentially misleading conclusions about an observed or lack of observed association between a clinical process of care and an outcome in the context of observational studies, individuals conducting and interpreting such studies should carefully consider, evaluate, and acknowledge these types of challenges.

Translation of acute coronary syndrome therapies: from evidence to routine clinical practice

BACKGROUND

The use of evidence-based therapies has improved the outcome of patients with acute coronary syndrome (ACS), but there is a time lag between the generation of clinical evidence and its application in routine clinical practice. We sought to quantify temporal lags in the lifecycle of American College of Cardiology (ACC)/American Heart Association (AHA) class IA ACS therapies.

METHODS

Using current and historical ACC/AHA guideline publications, we retrieved publication dates of pivotal clinical trials (PCTs) and class IA guideline-recommended therapies for patients with ST-elevation myocardial infarction (STEMI) and unstable angina (UA)/non-STEMI (NSTEMI). Clinical practice uptake data for each therapy were retrieved from the National Registry for Myocardial Infarction, Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes with Early Implementation of the ACC/AHA Guidelines, and Acute Coronary Treatment and Intervention Outcomes Network Registry-Get with the Guidelines, which are registries containing publicly available peer-reviewed data. Descriptive data were calculated and compared for each phase of the evidence lifecycle for both STEMI and UA/NSTEMI drug classifications.

RESULTS

We identified 11 class IA- and 4 class IB/IC-recommended therapies for acute, inhospital, and discharge use for patients with STEMI or UA/NSTEMI. The median time lags were 2 years (interquartile range [IQR], 1-4 years) from PCT to practice guideline recommendation, 14 years (IQR, 11-15 years) from guideline recommendation to 90% practice uptake, and overall, a 16-year median (IQR, 13-19 years) from PCT to 90% practice uptake.

CONCLUSIONS

The time of PCT publication to meaningful uptake of class IA ACS therapies into clinical practice took a median of 16 years. This significant time lag indicates systemic barriers to the translation of therapeutics into routine clinical practice.

Knowledge of signs and symptoms of heart attack and stroke among Singapore residents

AIM

To determine the level of knowledge of signs and symptoms of heart attack and stroke in Singapore resident population, in comparison to the global community.

METHODS

A population based, random sample of 7,840 household addresses was selected from a validated national sampling frame. Each participant was asked eight questions on signs and symptoms of heart attack and 10 questions on stroke.

RESULTS

The response rate was 65.2% with 4,192 respondents. The level of knowledge for preselected, common signs and symptoms of heart attack and stroke was 57.8% and 57.1%, respectively. The respondents scored a mean of 5.0 (SD 2.4) out of 8 for heart attack, while they scored a mean of 6.8 (SD 2.9) out of 10 for stroke. Respondents who were ≥ 50 years, with lower educational level, and unemployed/retired had the least knowledge about both conditions. The level of knowledge of signs and symptoms of heart attack and stroke in Singapore is comparable to USA and Canada.

CONCLUSION

We found a comparable knowledge of stroke and heart attack signs and symptoms in the community to countries within the same economic, educational, and healthcare strata. However older persons, those with lower educational level and those who are unemployed/retired, require more public health education efforts.

Cardiogenic shock complicating acute coronary syndromes: insights from the Global Registry of Acute Coronary Events

INTRODUCTION

Despite advances in the management of patients with an acute coronary syndrome (ACS), cardiogenic shock (CS) remains the leading cause of death in these patients. The objective of this observational study was to describe the characteristics, management, and hospital outcomes of patients with an ACS complicated by CS. Our secondary study objective was to describe trends in the incidence and hospital case-fatality rates (CFRs) of CS and predictors of increased hospital mortality in these high-risk patients.

METHODS

The population consisted of patients enrolled in the GRACE study between 1999 and 2007 who were hospitalized with an ACS.

RESULTS

During the years under study, 2,992 patients (4.6%) developed CS. Patients with CS were more likely to be older, have a history of diabetes or atrial fibrillation, and present with a higher pulse rate or cardiac arrest. Cardiac catheterization was performed on 1,706 (57%) and in-hospital revascularization on 1,408 patients (47%) with CS. Patients with CS were less likely to receive evidence-based cardiac medications compared with patients who did not develop CS. The in-hospital CFR of patients with CS was 59.4%, compared with 2.3% in those who did not develop CS. Factors associated with an increased risk of dying in patients with CS included advanced age, diabetes mellitus, angina, and stroke. Adjusted incidence rates and hospital CFRs of CS showed modest declines over time.

CONCLUSION

Continued efforts are needed to reduce the incidence and CFRs of CS complicating ACS.

A review of cardiogenic shock in acute myocardial infarction

Cardiogenic shock continues to be the most common cause of death in patients hospitalized with acute myocardial infarction. It has also been frequently associated with ST-segment elevation myocardial infarction (STEMI) and patients with co-morbidities. Cardiogenic shock presents with low systolic blood pressure and clinical signs of hypoperfusion. Rapid diagnosis and supportive therapy in the form of medications, airway support and intra-aortic balloon counterpulsation is required. Initial stabilization can be followed by reperfusion by fibrinolytic therapy, emergent percutaneous intervention (PCI) or coronary artery bypass grafting (CABG). The latter two have been found to decrease mortality in the long term. Research is being carried out on the role of inflammatory mediators in the clinical manifestation of cardiogenic shock. Mechanical support devices also show promise in the future.

Trends in in-hospital mortality and six-month outcomes in patients with a first acute myocardial infarction. Change over the last decade

INTRODUCTION AND OBJECTIVES

Treatment of acute myocardial infarction (AMI) has changed considerably in recent years. The objective of this study was to investigate differences in in-hospital mortality and 6-month outcomes after a first AMI between patients who participated in two trials, in 1992-1994 and 2001-2003, respectively.

METHODS

The study involved 1440 consecutive patients with a first AMI who were admitted to four university hospitals during 1992-1994 (the RESCATE-I trial) and 1288 with a first AMI who met the same diagnostic criteria and who were admitted to the same hospitals during 2001-2003 (the RESCATE-II trial). Patient management, in-hospital mortality and 6-month prognosis and outcomes were compared between the two trials.

RESULTS

Reperfusion therapy was carried out in 60.7% of patients in the first trial and in 72.6% in the second (P< .001). In the RESCATE-II trial, the median door-to-needle time was shorter (41 min vs. 93 min; P< .001) and patients more frequently underwent coronary angiography (65.2% vs. 28.1%; P< .001) and revascularization (34.9% vs. 8.1%; P< .001). In addition, in-hospital mortality was lower in RESCATE-II (7.5% vs. 10.9%; P< .001). After adjustment for age, sex, comorbidity, AMI severity and reperfusion therapy, the odds ratio for in-hospital mortality in RESCATE-II compared with the first trial was 0.52 (95% confidence interval, 0.31-0.86). In addition, mortality (1.4% vs. 3.6%; P=.001) and readmissions at 6 months were also lower in RESCATE-II.

CONCLUSIONS

Both in-hospital and 6-month mortality in patients with a first AMI decreased during the last decade, probably due to more frequent reperfusion and revascularization therapy and better medical treatment.

Quality of care for acute myocardial infarction in 58 U.S. emergency departments

OBJECTIVES

The objectives of this study were to determine concordance of emergency department (ED) management of acute myocardial infarction (AMI) with guideline recommendations and to identify ED and patient characteristics predictive of higher guideline concordance.

METHODS

The authors conducted a chart review study of ED AMI care as part of the National Emergency Department Safety Study (NEDSS). Using a primary hospital discharge diagnosis of AMI (International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM], codes 410.XX), a random sample of ED visits for AMI in 58 urban EDs across 20 U.S. states between 2003 and 2006 were identified. Concordance with American College of Cardiology/American Heart Association (ACC/AHA) guideline recommendations was evaluated using five individual quality measures and a composite concordance score. Concordance scores were calculated as the percentage of eligible patients who received guidelines-recommended care. These percentage scores were rescaled from 0 to 100, with 100 indicating perfect concordance.

RESULTS

The cohort consisted of 3,819 subjects; their median age was 65 years, and 62% were men. The mean (± standard deviation [SD]) ED composite concordance score was 61 ± 8), with a broad range of values (42 to 84). Except for aspirin use (mean concordance, 82), ED concordance scores were low (beta-blocker use, 56; timely electrocardiogram [ECG], 41; timely fibrinolytic therapy, 26; timely ED disposition for primary percutaneous coronary intervention [PCI] candidates, 43). In multivariable analyses, older age (beta-coefficient per 10-year increase, -1.5; 95% confidence interval [CI] = -2.4 to -0.5) and southern EDs (beta-coefficient, -5.2; 95% CI = -9.6 to -0.9) were associated with lower guideline concordance, whereas ST-segment elevation on initial ED ECG was associated with higher guideline concordance (beta-coefficient, 3.6; 95% CI = 1.5 to 5.7).

CONCLUSIONS

Overall ED concordance with guideline-recommended processes of care was low to moderate. Emergency physicians should continue to work with other stakeholders in AMI care, such as emergency medical services (EMS) and cardiologists, to develop strategies to improve care processes.

beta-Blocker use following myocardial infarction: low prevalence of evidence-based dosing

BACKGROUND

Quality improvement programs have shown increased use of beta-blockers post-myocardial infarction (MI), but there are no data on whether appropriate doses are administered.

METHODS

In a prospective registry that enrolled consecutive patients with MI, we evaluated beta-blocker dosing at discharge after MI and 3 weeks later and assessed clinical predictors for treatment with very low doses. We studied 1,971 patients (70.8% male) with a mean age of 63.9 +/- 13.7 years, of whom 48.2% had an ST-elevation MI.

RESULTS

beta-Blocker utilization rates following MI were 93.2% at discharge: 20.1% received <25% of target dose, 36.5% received 25% of target dose, 26.4% received 26% to 50% of target dose, and 17.0% received >50% of target dose. Between discharge and 3 weeks, 76.4% had no change in beta-blocker dose, with 11.9% and 11.6% having their dose reduced and increased, respectively. Absence of hypertension, acute percutaneous coronary intervention, older age, and no angiotensin-converting enzyme inhibitor therapy were consistent predictors of treatment with very low beta-blocker doses.

CONCLUSIONS

Underdosing of beta-blockers is highly prevalent among patients post-MI. This represents an important opportunity in quality improvement for the care of patients who have suffered an MI.

Reduction in acute myocardial infarction mortality in the United States: risk-standardized mortality rates from 1995-2006

CONTEXT

During the last 2 decades, health care professional, consumer, and payer organizations have sought to improve outcomes for patients hospitalized with acute myocardial infarction (AMI). However, little has been reported about improvements in hospital short-term mortality rates or reductions in between-hospital variation in short-term mortality rates.

OBJECTIVE

To estimate hospital-level 30-day risk-standardized mortality rates (RSMRs) for patients discharged with AMI.

DESIGN, SETTING, AND PATIENTS

Observational study using administrative data and a validated risk model to evaluate 3,195,672 discharges in 2,755,370 patients discharged from nonfederal acute care hospitals in the United States between January 1, 1995, and December 31, 2006. Patients were 65 years or older (mean, 78 years) and had at least a 12-month history of fee-for-service enrollment prior to the index hospitalization. Patients discharged alive within 1 day of an admission not against medical advice were excluded, because it is unlikely that these patients had sustained an AMI.

MAIN OUTCOME MEASURE

Hospital-specific 30-day all-cause RSMR.

RESULTS

At the patient level, the odds of dying within 30 days of admission if treated at a hospital 1 SD above the national average relative to that if treated at a hospital 1 SD below the national average were 1.63 (95% CI, 1.60-1.65) in 1995 and 1.56 (95% CI, 1.53-1.60) in 2006. In terms of hospital-specific RSMRs, a decrease from 18.8% in 1995 to 15.8% in 2006 was observed (odds ratio, 0.76; 95% CI, 0.75-0.77). A reduction in between-hospital heterogeneity in the RSMRs was also observed: the coefficient of variation decreased from 11.2% in 1995 to 10.8%, the interquartile range from 2.8% to 2.1%, and the between-hospital variance from 4.4% to 2.9%.

CONCLUSION

Between 1995 and 2006, the risk-standardized hospital mortality rate for Medicare patients discharged with AMI showed a significant decrease, as did between-hospital variation.

Assessing the appropriateness of coronary revascularization: the University of Maryland Revascularization Appropriateness Score (RAS) and its comparison to RAND expert panel ratings and American College of Cardiology/American Heart Association guidelines with regard to assigned appropriateness rating and ability to predict outcome

BACKGROUND

Significant regional variation in procedural frequencies has led to the development of the RAND and American College of Cardiology/American Heart Association (ACC/AHA) guidelines; however, they may be difficult to apply in clinical practice. The University of Maryland Revascularization Appropriateness Score (RAS) was created to address the need for a simplified point scoring system.

HYPOTHESIS

The study was undertaken to compare revascularization appropriateness ratings yielded by the RAND Expert Panel Ratings, ACC/AHA guidelines, and the University of Maryland RAS.

METHODS

We applied these three revascularization appropriateness scoring systems to 153 catheterization laboratory patients with a variety of cardiac diagnoses and treatments. For each patient, appropriateness scores assigned by each of the three systems were compared with each other and with the actual treatment delivered. Concordance of care with appropriateness score was then correlated with outcome.

RESULTS

There were significant differences among all three scoring systems in their ratings and in the concordance of treatment with appropriateness rating. When treatment provided was concordant with RAND ratings, there was a lower occurrence of subsequent coronary artery bypass grafting (CABG), the composite end point of either CABG or percutaneous transluminal coronary angioplasty (PTCA), and the composite end point of death, myocardial infarction (MI), or revascularization. When treatment was concordant with the ACC/AHA guidelines, there was lower occurrence of all-cause mortality, PTCA, the composite end point of either CABG or PTCA, and the composite end point of death, MI, or revascularization. When treatment provided was concordant with the RAS, there was lower occurrence of cardiac death, all-cause death, CABG, the composite end point of either CABG or PTCA, and the composite end point of death, MI, or revascularization.

CONCLUSIONS

The RAS is a simple scoring system to assess revascularization appropriateness. When the RAND, ACC/AHA, and RAS systems are compared in a catheterization laboratory population, they rate the same patient differently and vary in their correlation of appropriateness rating with outcome.

Clinical outcome and quality of life of octogenarian patients following percutaneous coronary intervention or surgical coronary revascularization

BACKGROUND

Thus far, the outcome and effect of percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) surgery on the quality of life of octogenarian patients has not been accurately assessed in Japan.

METHODS AND RESULTS

A retrospective analysis of the outcome of invasive coronary revascularization in 130 elderly patients (age, > or =80 years) with ischemic coronary disease was carried out. Their current quality of life was determined by the Seattle Angina Questionnaire. Although the in-hospital death rate was relatively high (21.6% after PCI and 14.3% after CABG surgery), the long-term outcome of the patients who did not die during the in-hospital period after the PCI/CABG surgery was acceptable (5-year survival rate, >60%). All domains of the questionnaire received a favorable score from a majority of the survivors, irrespective of the treatment they received.

CONCLUSIONS

The quality of life and longevity of the octogenarian patients following extensive invasive revascularization for ischemic coronary artery disease were satisfactory.

Bolus thrombolytic infusion during prolonged refractory cardiac arrest of undiagnosed cause

Acute myocardial infarction (AMI) and pulmonary embolism (PE) account for about 70% of cardiac arrest. Although thrombolytic therapy is an effective therapy for both AMI and PE, it is not routinely recommended during cardiopulmonary resuscitation (CPR) for fear of life threatening bleeding complications. Numerous case reports and retrospective studies have suggested a beneficial effect of thrombolytics in cardiac arrest secondary to AMI and PE; however, we present a case of successful use of bolus thrombolytics during CPR in a patient with undifferentiated cardiac arrest (undiagnosed cause) after prolonged conventional resuscitation without success.

Delay in Time to Receipt of Thrombolytic Medication Among Medicare Patients With Kidney Disease

BACKGROUND

Patients with kidney disease and acute myocardial infarction (AMI) receive standard therapy, including thrombolytic medication, less frequently than patients with normal kidney function. Our goal is to identify potential differences in thrombolytic medication delays and thrombolytic-associated bleeding events by severity of kidney disease.

METHODS

This is a retrospective cohort analysis of Cooperative Cardiovascular Project data for all Medicare patients with AMI from 4,601 hospitals. Outcome measures included time to administration of thrombolytic medication censored at 6 hours and bleeding events.

RESULTS

Of 109,169 patients (mean age, 77.4 years; 50.6% women), 13.9% received thrombolysis therapy. Average time to thrombolytic therapy was longer in patients with worse kidney function. Adjusted hazard ratios for minutes to thrombolytic therapy were 0.83 (95% confidence interval [CI], 0.79 to 0.87) for patients with a serum creatinine level of 1.6 to 2.0 mg/dL (141 to 177 micromol/L) and 0.58 (95% CI, 0.53 to 0.63) for patients with a creatinine level greater than 2.0 mg/dL (>177 micromol/L) or on dialysis therapy compared with those with normal kidney function. Odds ratios for bleeding events in patients administered thrombolytics versus those who were not decreased with worse kidney function: adjusted odds ratios, 2.28 (95% CI, 2.16 to 2.42) in patients with normal kidney function and 1.84 (95% CI, 1.09 to 3.10) in dialysis patients.

CONCLUSION

Patients with worse kidney function experienced treatment delays, but were not at greater risk for thrombolysis-associated excess bleeding events. Physician concerns of thrombolytic-associated bleeding may not be sufficient reason to delay the administration of thrombolytic medication.

Association Between Functional Status and Use and Effectiveness of Beta-Blocker Prophylaxis in Elderly Survivors of Acute Myocardial Infarction

OBJECTIVES

To examine whether physical and cognitive impairments explain low use of beta-blockers in elderly patients and whether functionally impaired older adults have improved survival if a beta-blocker is prescribed at hospital discharge.

DESIGN

Cross-sectional and retrospective cohort study.

SETTING

Acute care hospitals in the United States.

PARTICIPANTS

National cohort of 45,370 elderly acute myocardial infarction survivors, with no chart-documented contraindications to beta-blocker treatment.

MEASUREMENTS

The main outcome measures were beta-blocker prescription at hospital discharge and 1-year survival.

RESULTS

Fifty percent (n=22,683) of eligible patients were prescribed a beta-blocker at discharge. Older age and functional impairments (incontinence, mobility impairment, and cognitive impairment) were independently associated with decreased use of beta-blockers. The odds ratios for prescribing a beta-blocker at hospital discharge were 0.82 (95% confidence interval (CI)=0.77-0.86), 0.63 (95% CI=0.56-0.71), and 0.40 (95% CI=0.32-0.51) for persons with one, two, and three impairments, respectively, compared with those with no impairments. In survival analysis, patients prescribed a beta-blocker were 21% less likely than nonrecipients to die within 1 year of follow-up (relative risk=0.79, P=.0001). Similar survival benefit was observed in patients with and without functional impairments.

CONCLUSION

This study shows a strong association between functional impairment and the use of beta-blockers after acute myocardial infarction in elderly patients. The results suggest that increasing use of beta-blockers in this group provides an opportunity to improve outcomes.

Clinical characteristics and early outcomes of very elderly patients in the reperfusion era

BACKGROUND

Not much data is available regarding "real-world" clinical experience of very elderly patients with acute myocardial infarction (AMI) in the reperfusion era.

METHODS

We reviewed 483 patients (26%) between the ages of 75 and 85 from the 1855 patients with AMI. We analyzed 264 patients treated with reperfusion therapy (55%) and 219 patients treated with conservative therapy (45%) on their clinical characteristics and early outcomes.

RESULTS

Patients treated with reperfusion therapy were slightly younger (79.0 vs. 80.0 years, P=0.01), presented earlier (205 vs. 400 minutes, P<0.01) and had higher peak creatine kinase values (2634 vs. 1407 IU/l, P<0.01) than those treated with conservative therapy. Other clinical profiles including sex, prior myocardial infarction, hypertension, diabetes, and infarct location were similar to each other. There was a 92% success for reperfusion therapy. The incidence of recurrent ischemia, cardiac rupture, and cerebral hemorrhage was not significantly different between the two groups. In-hospital mortality in this study was 20.5%. In-hospital mortality was not significantly different between the two groups (19% vs. 23%, P=0.25). The multivariate analysis showed that age, infarct location, and Killip class were correlated to in-hospital mortality. The leading cause of in-hospital death was pump failure.

CONCLUSIONS

Older age and late presentation were correlated to conservative therapy in very elderly patients with AMI. Early outcomes were similar between the two treatment groups. In-hospital mortality seemed to be associated with impaired myocardial reserve.

Major bleeding complications after cardiopulmonary resuscitation: impact of thrombolytic treatment

OBJECTIVE

The risk of bleeding complications caused by thrombolysis in patients with cardiac arrest and prolonged cardiopulmonary resuscitation is unclear. We evaluate the complication rate of systemic thrombolysis in patients with out-of-hospital cardiac arrest caused by acute myocardial infarction, especially in relation to duration of cardiopulmonary resuscitation.

DESIGN

The study was designed as retrospective cohort study, the risk factor being systemic thrombolysis and the end-point major haemorrhage, defined as life-threatening and/or need for transfusion. Over 10.5 years, emergency cardiac care data, therapy, major haemorrhage and outcome of 265 patients with acute myocardial infarction admitted to an emergency department after successful cardiopulmonary resuscitation were registered.

RESULTS

We observed major haemorrhage in 13 of 132 patients who received thrombolysis (10%, 95% confidence interval 5-15%), five of these survived to discharge, none died because of this complication. Major haemorrhage occurred in seven of 133 patients in whom no thrombolytic treatment had been given (5%, 95% confidence interval 1-9%), two of these survived to discharge. Taking into account baseline imbalances between the groups, the risk of bleeding was slightly increased if thrombolytics were used (odds ratio 2.5, 95% confidence interval 0.9-7.4) but this was not significant (P = 0.09). There was no clear association between duration of resuscitation and bleeding complications (z for trend = 1.52, P = 0.12). Survival was not significantly better in patients receiving thrombolysis (odds ratio 1.6, 0.9-3.0, P = 0.12).

CONCLUSIONS

Bleeding complications after cardiopulmonary resuscitation are frequent, particularly in patients with thrombolytic treatment, but do not appear to be related to the duration of resuscitation. In the light of possible benefits on outcome, thrombolytic treatment should not be withheld in carefully selected patients.

Emergency drugs

There is universal agreement that dentists require emergency drugs to be readily available. Opinions differ as to the specific drugs that should comprise an emergency kit. This article has provided one opinion. Oxygen, epinephrine, nitroglycerin, injectable diphenhydramine or chlorpheniramine, albuterol, and aspirin should be readily available in a dental office. Other drugs such as glucagon, atropine, ephedrine, hydrocortisone, morphine or nitrous oxide, naloxone, midazolam or lorazepam, and flumazenil should also be considered. There are differences in the level of training of dentists in the management of medical emergencies [25]. Therefore the final decision should be made by the individual dentist who is in the best position to determine the appropriateness of these agents for the particular practice. Despite the best efforts at prevention, emergencies may still arise. Plans to manage these events are needed and there is the possibility that the drugs discussed above may be required. Their presence may save a life.

Benefits of late reperfusion in the treatment of acute myocardial infarction

Early reperfusion of the infarct-related coronary artery is very much effective to treat the patients with acute myocardial infraction. However, there are many clinical as well as experimental evidences supporting the efficacy of late reperfusion therapy. In this article, effects of late reperfusion on mortality, left ventricular function, left ventricular dilatation and remodeling, or electrical stability were summarized. Also, the possible mechanisms for benefits of late reperfusion were discussed and the special role of epicardial rim bring about those benefits was emphasized.

Dialing 911: a call to action

Cardiovascular disease and stroke are the nation's leading causes of disability and death. Scientific advances have provided newer treatments that, when applied effectively and in time, save a significant number of lives. Multiple factors in our system of delivery impede our ability to apply effective treatments, but with an analysis of the components of care, each of us can take leadership roles in our communities to improve the chain of survival. These elements and the science supporting each are briefly reviewed.

The relation between managed care market share and the treatment of elderly fee-for-service patients with myocardial infarction

PURPOSE

To determine if greater managed care market share is associated with greater use of recommended therapies for fee-for-service patients with acute myocardial infarction.

SUBJECTS AND METHODS

We examined the care of 112,900 fee-for-service Medicare beneficiaries aged > or = 65 years who resided in one of 320 metropolitan statistical areas and who were admitted with an acute myocardial infarction between February 1994 through July 1995. Use of recommended medical treatments and 30-day survival were determined for areas with low (<10%), medium (10% to 30%), and high (>30%) managed care market share.

RESULTS

After adjustment for severity of illness, teaching status of the admission hospital, and area characteristics, areas with high levels of managed care had greater use of beta-blockers (relative risk [RR] for greater use = 1.18; 95% confidence interval [CI]: 1.06 to 1.29) and aspirin at discharge (RR = 1.05; 95% CI: 1.02 to 1.07), but less appropriate coronary angiography (RR = 0.93; 95% CI: 0.86 to 1.01) and reperfusion (RR = 0.95; 95% CI: 0.85 to 1.03) when compared with areas with low levels of managed care.

CONCLUSIONS

Medicare beneficiaries with fee-for-service insurance who resided in areas with high managed care activity were more likely to have received appropriate treatment with beta-blockers and aspirin, and less likely to have undergone coronary angiography following admission for myocardial infarction. Thus, the effects of managed care may not be limited to managed care enrollees.

Interaction between vasodilators and vasopressin in internal mammary artery and clinical significance

BACKGROUND

Arginine vasopressin (AVP) has recently been demonstrated as an alternative in the treatment of severe refractory vasodilatation in coronary artery bypass grafting. However, AVP may be a spasmogen for graft spasm. We compared the in vitro antispastic effect among calcium-channel antagonists (nifedipine, diltiazem, and verapamil), nitroglycerin, and the highly selective AVP (V1) receptor antagonist [1-deaminopenicillamine, 4-valine, 8-D-arginine] vasopressin.

METHODS

Human internal mammary artery segments (n = 218) were studied in organ baths. The inhibitory effects of the above vasodilators on AVP-mediated contraction were studied in two ways: relaxation with AVP precontraction and depression of the AVP-induced contraction after pretreatment with vasodilators.

RESULTS

All three calcium-channel antagonists caused limited relaxation (18.3%+/-5.4% for nifedipine, n = 11; 22.2%+/-3.8% for verapamil, n = 10; and 26.2%+/-7.5% for diltiazem, n = 9). The plasma concentration of calcium-channel antagonists had no significant depression effect on the AVP-induced contraction. In contrast, [1-deaminopenicillamine, 4-valine, 8-D-arginine] vasopressin caused full (100%, n = 11) and nitroglycerin caused nearly full (93%+/-3%, n = 10) relaxation. Pretreatment with [1-deaminopenicillamine, 4-valine, 8-D-arginine] vasopressin (10(-8), 10(-7), or 10(-6) mol/L, respectively) significantly increased the effective concentration for 50% of the AVP-induced contraction (10(-8.6)+/-10(0.1) mol/L, p = 0.009; 10(-7.8)+/-10(0.07) mol/L, p = 0.000; or 10(-6.9)+/-10(0.11) mol/L, p = 0.000 versus the control, 10(-9.24)+/-10(0.16) mol/L). However, nitroglycerin only slightly depressed the AVP-induced contraction.

CONCLUSIONS

[1-Deaminopenicillamine, 4-valine, 8-D-arginine] vasopressin may provide specific antispastic effect in either prophylaxis or treatment of the AVP-related vasospasm in the internal mammary artery. Nitroglycerin may be effective in treatment but has little effect on prophylaxis. Use of calcium-channel antagonists may have little benefit in AVP-related vasospasm.

Thrombolytic therapy after cardiac arrest and its effect on neurological outcome

OBJECTIVE

the aim of the study is to investigate the effect of thrombolytic therapy on neurological outcome in patients after cardiac arrest due to acute myocardial infarction. Laboratory investigations have demonstrated that thrombolytic therapy after cardiopulmonary resuscitation improves neurological function.

METHODS

from July 1991 to June 1996, patients with witnessed ventricular fibrillation cardiac arrest due to acute MI and successful restoration of spontaneous circulation admitted to the emergency department were analyzed retrospectively. A logistic regression model was used to assess the association between thrombolytic therapy and neurological outcome [best cerebral performance category (CPC) within 6 months after cardiac arrest].

RESULTS

all 157 patients [median age 57 years (IQR 50-69)] were analyzed. Thrombolytic therapy was applied in 42 patients (27%). With thrombolytic therapy good functional neurological recovery (CPC 1 or 2) was achieved more frequently (69 vs. 50%, P=0.03). After controlling for age, prehospital dosage of epinephrine, and the duration of cardiac arrest we found a non significant trend towards good neurological recovery when thrombolytic therapy was given (OR 1.9, 95% CI 0.8-4.6).

CONCLUSION

thrombolytic therapy after cardiac arrest due to acute myocardial infarction is associated with improved neurological outcome.