Use of emergency medical services in acute myocardial infarction and subsequent quality of care: observations from the National Registry of Myocardial Infarction 2

BACKGROUND

National practice guidelines strongly recommend activation of the 9-1-1 Emergency Medical Systems (EMS) by patients with symptoms consistent with an acute myocardial infarction (MI). We examined use of the EMS in the United States and ascertained the factors that may influence its use by patients with acute MI.

METHODS AND RESULTS

From June 1994 to March 1998, the National Registry of Myocardial Infarction 2 enrolled 772 586 patients hospitalized with MI. We excluded those who transferred in, arrived at the hospital >6 hours from symptom onset, or who were in cardiogenic shock. We compared baseline characteristics and initial management for patients who arrived by ambulance versus self-transport. EMS was used in 53.4% of patients with MI, a proportion that did not vary significantly over the 4-year study period. Nonusers of the EMS were on average younger, male, and at relatively lower risk on presentation. In addition, payer status was significantly associated with EMS use. Use of EMS was independently associated with slightly wider use of acute reperfusion therapies and faster time intervals from door to fibrinolytic therapy (12.1 minutes faster, P<0.001) or to urgent PTCA (31.2 minutes faster, P<0.001).

CONCLUSIONS

Only half of patients with MI were transported to the hospital by ambulance, and these patients had greater and significantly faster receipt of initial reperfusion therapies. Wider use of EMS by patients with suspected MI may offer considerable opportunity for improvement in public health.

Relation between hospital intra-aortic balloon counterpulsation volume and mortality in acute myocardial infarction complicated by cardiogenic shock

BACKGROUND

Increasing evidence suggests an inverse relationship between outcome and the total number of invasive cardiac procedures performed at a given hospital. The purpose of the present study was to determine if a similar relationship exists between the number of intra-aortic balloon counterpulsation (IABP) procedures performed at a given hospital per year and the in-hospital mortality rate of patients with acute myocardial infarction complicated by cardiogenic shock.

METHODS AND RESULTS

We analyzed data of 12 730 patients at 750 hospitals enrolled in the National Registry of Myocardial Infarction 2 from 1994 to 1998. The hospitals were divided into tertiles (low-, intermediate-, and high-IABP volume hospitals) according to the number of IABPs performed at the given hospital per year. The median number of IABPs performed per hospital per year was 3.4, 12.7, and 37.4 IABPs at low-, intermediate-, and high-volume hospitals, respectively. Of those patients who underwent IABP, there were only minor differences in baseline patient characteristics between the 3 groups. Crude mortality rate decreased with increasing IABP volume: 65.4%, lowest volume tertile; 54.1%, intermediate volume tertile; and 50.6%, highest volume tertile (P for trend <0.001). This mortality difference represented 150 fewer deaths per 1000 patients treated at the high IABP hospitals. In the multivariate analysis, high hospital IABP volume for patients with acute myocardial infarction was associated with lower mortality (OR=0.71, 95% CI=0.56 to 0.90), independent of baseline patient characteristics, hospital factors, treatment, and procedures such as PTCA.

CONCLUSIONS

Among the myocardial infarction patients with cardiogenic shock who underwent IABP placement, mortality rate was significantly lower at high-IABP volume hospitals compared with low-IABP volume hospitals.

Early use of glycoprotein IIb/IIIa inhibitors in non-ST-elevation acute myocardial infarction: observations from the National Registry of Myocardial Infarction 4

OBJECTIVES

We sought to identify patient and hospital features associated with early glycoprotein (GP) IIb/IIIa inhibitor therapy for non-ST-elevation (NSTE) myocardial infarction (MI) and to relate this treatment to in-hospital outcomes.

BACKGROUND

Glycoprotein IIb/IIIa inhibitors have improved outcomes in randomized trials of NSTE MI, leading national treatment guidelines to recommend their use. Their actual use, safety, and effectiveness have not been well characterized beyond trial populations.

METHODS

We studied 60,770 patients with NSTE MI treated between July 2000 and July 2001 at 1,189 hospitals in a U.S. registry. Using logistic regression, we identified patient and hospital features associated with GP IIb/IIIa inhibition within 24 h after presentation. We also compared outcomes by early treatment versus no treatment after adjusting for patient and hospital characteristics and treatment propensity.

RESULTS

Only 25% of eligible patients received early GP IIb/IIIa therapy. Elderly patients, women, minority patients, and those without private insurance received such therapy less often than their counterparts. Treated patients had lower unadjusted in-hospital mortality (3.3% vs. 9.6%, p < 0.0001) remaining significantly lower after adjustment for patient risk, treatment propensity, and hospital characteristics (adjusted odds ratio, 0.88; 95% confidence interval, 0.79 to 0.97). Hospitals that adopted early GP IIb/IIIa inhibition more rapidly also had lower adjusted mortality rates than those slower to adopt such therapy.

CONCLUSIONS

Glycoprotein IIb/IIIa inhibitor therapy appears to be underused in early management of NSTE MI patients. Because this therapy is associated with better outcomes, it represents a target for quality improvement.

Evaluating the potential for prezygotic isolation and hybridization between landlocked and anadromous alewife (Alosa pseudoharengus) following secondary contact

The recent increase in river restoration projects is altering habitat connectivity for many aquatic species, increasing the chance that previously isolated populations will come into secondary contact. Anadromous and landlocked alewife (Alosa pseudoharengus) are currently undergoing secondary contact as a result of a fishway installation at Rogers Lake in Old Lyme, Connecticut. To determine the degree of prezygotic isolation and potential for hybridization between alewife life history forms, we constructed spawning time distributions for two anadromous and three landlocked alewife populations using otolith-derived age estimates. In addition, we analyzed long-term data from anadromous alewife migratory spawning runs to look for trends in arrival date and spawning time. Our results indicated that anadromous alewife spawned earlier and over a shorter duration than landlocked alewife, but 3%-13% of landlocked alewife spawning overlapped with the anadromous alewife spawning period. The degree of spawning time overlap was primarily driven by annual and population-level variation in the timing of spawning by landlocked alewife, whereas the timing and duration of spawning for anadromous alewife were found to be relatively invariant among years in our study system. For alewife and many other anadromous fish species, the increase in fish passage river restoration projects in the coming decades will re-establish habitat connectivity and may bring isolated populations into contact. Hybridization between life history forms may occur when prezygotic isolating mechanisms are minimal, leading to potentially rapid ecological and evolutionary changes in restored habitats.

The development and evaluation of new versions of the written examination for the American Heart Association Advanced Cardiac Life Support provider course

STUDY OBJECTIVE

To create new versions of the written, multiple-choice examination used in the American Heart Association (AHA) Advanced Cardiac Life Support course, evaluate their reliability and difficulty, and then design revised versions with improved reliability and of standardized difficulty.

DESIGN

Psychometric evaluation of new versions of the AHA Advanced Cardiac Life Support test and revisions.

SETTING

AHA Advanced Cardiac Life Support courses.

PARTICIPANTS

Candidates for completion of AHA Advanced Cardiac Life Support provider courses in five states.

INTERVENTION

The course content was divided into 11 content areas that were weighted for importance and appropriateness for testing in a multiple-choice format. The weights were used to construct a blueprint for a 50-question, multiple-choice examination. Five versions of the examination were then constructed based on the content blueprint, drawing from new questions and expert revision of previously written questions. Reliability and difficulty were assessed using 915 administrations at five different sites nationwide. The initial test versions differed in their degree of difficulty, which was not explained by demographic factors. The results were used to revise three of the versions to improve reliability and equalize difficulty of the versions.

MEASUREMENTS AND MAIN RESULTS

The final five versions have estimated reliability ranging from Cronbach's alpha of .62 to .86. Mean scores ranged from 87.4% to 89.1%.

CONCLUSION

After field testing and revision, five examinations with acceptable reliability and roughly equal difficulty were constructed. The new examinations test the participants' knowledge of important aspects of resuscitation science and practice based on a blueprint of the course content.

Acute ischemic syndromes. Adjunctive therapy

The acute coronary syndromes (ACS) represent a heterogeneous group of patients along a continuum of risk from unstable angina to non-ST-segment elevation myocardial infarction. ACS is a term that has been used to describe the constellation of clinical symptoms that represent acute myocardial ischemia. This article reviews the adjunctive medications that are used during emergency cardiovasculare care for the early management of patients experiencing the ACS. The adjunctive therapies are divided into early immediate treatment and then subsequent management in the acute care setting.