Therapeutic interventions in acute myocardial infarction. Survey of the ACCP Section on Clinical Cardiology

A systematic review of the effects of physician specialty on the treatment of coronary disease and heart failure in the United States

PURPOSE

To assess the effects of physician specialty on the knowledge, management, and outcomes of patients with coronary disease or heart failure.

MATERIALS AND METHODS

We performed a systematic search of MEDLINE from 1980 to 1997, as well as bibliographic references to articles about the effects of physician specialty on the knowledge, treatment, and outcomes of patients with coronary disease or heart failure in the United States.

RESULTS

Twenty-four articles met our criteria for inclusion (including eight that involved knowledge or self-reported practices, 14 that described actual practice patterns, and six that measured clinical outcomes). Cardiologists were more knowledgeable than generalist physicians about the optimal evaluation and management of coronary disease but not about the use of angiotensin-converting enzyme (ACE) inhibitors for heart failure. Patients with unstable angina or myocardial infarction were more likely to receive proven medical therapies, and possibly had improved outcomes, if they were treated by cardiologists. The use of lipid-lowering drugs after myocardial infarction was also more common among patients of cardiologists. ACE inhibitor use for heart failure was probably greater, and short-term readmission rates were lower, with cardiology care.

CONCLUSIONS

Patients with coronary disease or heart failure in the United States who are treated by cardiologists appear more likely to receive evidence-based care and probably have better outcomes. Investigation of collaborative models of care and innovative efforts to improve the use of proven therapies by physicians are needed.

[Incidence of use of various myocardial infarct treatments in 2 Swiss regions]

Two regions in Switzerland (Vaud-Fribourg and Ticino) participate in the WHO MONICA project (MONItoring of trends and determinants in CArdiovascular disease). Within this context, all hospitalizations of men for ischemic heart disease will be recorded during a period of ten years. All cases are classified according to uniform criteria, in three categories: definite myocardial infarction, possible myocardial infarction or no myocardial infarction. In 1986, the records were completed with a summary of treatments. The treatment of 334 patients with definite myocardial infarction, aged between 25 and 64 years, surviving after 27 days are analyzed (VD-FR: 217; TI: 117). Results show that anticoagulants were administered in a routine fashion (in 97% of the cases), whilst thrombolysis, applied in 1986 by only one hospital in each area, concerned only 9% of the patients. As compared to Ticino, VD-FR distinguished itself by its significantly higher use of anti-arrhythmia drugs (69% versus 47%; p less than 0.005), nitrates (97% versus 86%; p less than 0.005) and beta-blockers (57% versus 43%; p less than 0.05). Furthermore, patients from VD-FR spent more time in the intensive care unit (6.4 versus 3.7 days; p less than 0.005) and participated more frequently in rehabilitation programmes (47% versus 12%; p less than 0.005). The discussion compares the observed therapy with results published in the literature.

Cardiogenic shock after acute myocardial infarction. Incidence and mortality from a community-wide perspective, 1975 to 1988

BACKGROUND

Cardiogenic shock resulting from acute myocardial infarction is a serious complication with a high mortality rate, but little is known about whether its incidence or outcome has changed over time. As part of an ongoing population-based study of acute myocardial infarction, we examined trends over time in the incidence and mortality rate of cardiogenic shock after acute myocardial infarction.

METHODS

We studied 4762 patients with acute myocardial infarction who were admitted to 16 hospitals in the Worcester, Massachusetts, metropolitan area between 1975 and 1988. We determined the incidence of and short-term and long-term mortality due to cardiogenic shock in each of six years during this study period.

RESULTS

The incidence of cardiogenic shock complicating acute myocardial infarction remained relatively constant, averaging 7.5 percent. Multivariate regression analysis that controlled for variables affecting incidence revealed significant though inconsistent temporal trends in the incidence of cardiogenic shock. As compared with the risk in 1975, the adjusted relative risk (with 95 percent confidence interval) was 0.83 (0.54 to 1.28) in 1978, 0.96 (0.63 to 1.48) in 1981, 0.68 (0.42 to 1.12) in 1984, 1.16 (0.70 to 1.92) in 1986, and 1.65 (0.99 to 2.77) in 1988. The overall in-hospital mortality rate among patients with cardiogenic shock was significantly higher than that among patients without this complication (77.7 percent vs. 13.5 percent, P less than 0.001). The in-hospital mortality among the patients with shock did not improve between 1975 (73.7 percent) and 1988 (81.7 percent). Long-term survival during the 14-year follow-up period was significantly worse among patients who survived cardiogenic shock during hospitalization than among patients who did not have shock (P less than 0.001).

CONCLUSIONS

The results of this observational, community-wide study suggest that neither the incidence nor the prognosis of cardiogenic shock resulting from acute myocardial infarction has improved over time. Both in-hospital and long-term survival remain poor for patients with this complication.

Antithrombotic therapy in historical perspective

The history of antithrombotic therapy is traced over the past 5 decades, with a focus on the treatment of 2 major disorders: venous thromboembolism and acute myocardial infarction. Five subjects pertinent to clinical management decisions are discussed: (1) theories of thrombosis and coagulation, (2) tests of coagulation, (3) the availability of therapeutic interventions, (4) techniques for the diagnosis of vascular obstruction, and (5) the use and misuse of clinical trials.

Current practice patterns in the management of acute myocardial infarction. Survey of the American College of Chest Physicians

Over the past decade, the management of patients with acute myocardial infarction has undergone remarkable change due in part to the availability of new diagnostic and therapeutic modalities. Many of these techniques have gained widespread acceptance and use without the benefit of studies demonstrating efficacy. A survey of 391 members of the Section on Clinical Cardiology of the American College of Chest Physicians was conducted to assess current practice patterns in the management of acute myocardial infarction. Significant differences in the routine (greater than or equal to 50 percent of the time) use of various management approaches were found, with exercise tolerance testing, echocardiography, Holter monitoring, and cardiac rehabilitation frequently employed, whereas electrophysiologic studies, pyrophosphate scans, pulmonary artery catheterization, and cardiac pacing were infrequently used. Significant differences in the use of these procedures were noted with regard to the age of the physician and his or her geographic location of practice. These differences in practice patterns indicate that physicians have not reached consensus with regard to the value of these new diagnostic procedures and therapeutic approaches in the treatment of patients with acute myocardial infarction. Given the incremental costs of these procedures, clinical trials to assess their efficacy are clearly indicated.

Therapeutic trends in the management of patients with acute myocardial infarction (1975-1984): the Worcester Heart Attack Study

As part of an ongoing community-wide study of time trends in the incidence and case-fatality rates of patients hospitalized with acute myocardial infarction (MI) in all 16 Worcester, Massachusetts, metropolitan hospitals during the years 1975, 1978, 1981, and 1984, changes over time in the therapeutic management of 3263 patients with validated acute myocardial infarction were examined. Beta-blocker (21%, 1975; 52%, 1984) and nitrate (56%, 1975; 93%, 1984) therapy use increased dramatically over time. Use of antiplatelet agents was inconsistent over time, while use of digoxin remained stable, being used in approximately 40% of all patients over the four periods studied. Use of antiarrhythmic medications other than lidocaine decreased consistently over time (31%, 1975; 22%, 1984). Lidocaine use increased between 1975 (31%) and 1978 (52%) and then leveled off to being used in approximately 45% of hospitalized patients with acute MI in 1981 and 1984. A variety of demographic (e.g., age, sex, teaching hospital) and clinical characteristics (e.g., MI order, MI type, MI location, peak CPK findings, occurrence of acute clinical complications) were also associated with the use of these therapies for the combined study periods. The results of this population-based study suggest considerable changes over time in the therapeutic management of patients hospitalized with acute myocardial infarction and of numerous patient demographic and clinical factors associated with their use.