Changing characteristics and in-hospital outcome in patients admitted with acute myocardial infarction. Observations from 1982 to 1994.

BACKGROUND: During the past decade, various new treatments have become available for patients with acute myocardial infarction. The effects of these treatment modalities have been studied extensively in selected patient groups. These studies indicate that early diagnosis, risk stratification and prompt initiation of treatment are of crucial importance for optimal benefit. However, it is not known whether prognosis changed in all patients admitted with an acute myocardial infarction. Also, the characteristics of the infarct population may have changed over time because of new medication regimens, invasive interventions and awareness of the importance of risk factors. METHODS: We studied all patients admitted with acute myocardial infarction in 1982, 1988 and 1994. Information on baseline characteristics, clinical variables and all interventions was collected. FINDINGS: In those 3 years 223, 227 and 235 patients were admitted because of an acute myocardial infarction. Patients admitted in 1994 were older, more often female and less often had a previous cardiac history. More patients admitted in that year had previous balloon angioplasty and coronary bypass grafting. Smoking habits decreased during the past decade. In-hospital mortality was 38 (17%) in 1982, 23 (10%) in 1988 and 22 (9%) in 1994 (P < 0.05). Variables related to high risk for in-hospital death in 1982 were higher age, low systolic blood pressure, atrial fibrillation, absence of accelerated idioventricular rhythm, sustained ventricular tachycardia and signs of left ventricular dysfunction; in 1988 the occurrence of non-sustained ventricular tachycardia, Killip class more than I, the absence of thrombolytic therapy, percutaneous transluminal coronary angioplasty or coronary artery bypass grafting were independently related to in-hospital death. In 1994, high risk variables for in-hospital death were dyspnoea on admission, sustained ventricular tachycardia, female gender, higher creatinine on admission, and a previous cardiac history. INTERPRETATION: In-hospital mortality for unselected patients admitted with an acute myocardial infarction decreased between 1982 and 1988 and remained the same between 1988 and 1994, in spite of further ageing of the population. In the study period there has been a change in baseline characteristics and high risk variables for in-hospital death after myocardial infarction.

Did prognosis after acute myocardial infarction change during the past 30 years? A meta-analysis.

Much effort has been spent to improve survival after acute myocardial infarction. To investigate how effective this effort has been, a meta-analysis was performed of studies published between 1960 and 1987 concerning mortality after acute myocardial infarction. Thirty-six studies were analyzed. They were classified with respect to deaths in the hospital and at 1 month and the 5-year mortality rate starting at hospital discharge. Mortality was assessed from all studies by comparing studies from different institutions with use of identical inclusion criteria (externally controlled studies) and by analyzing studies reporting on changes in mortality in two or more comparable patient cohorts admitted to the same institution at different time periods (internally controlled studies). Reports on clinical trials (for example, thrombolytic therapy, beta-adrenergic blockade) in acute myocardial infarction were excluded. Average overall in-hospital mortality decreased from 29% during the 1960s to 21% during the 1970s and to 16% during the 1980s. The externally controlled studies also showed a declining trend: from 1960 to 1969, 32%, from 1970 to 1979, 19% and from 1980 to 1987, 15%. The 1-month overall mortality rate decreased from 31% during the 1960s to 25% during the 1970s and 18% during the 1980s externally controlled studies. Most internally controlled studies also showed significant improvement in in-hospital and 1-month survival. In contrast, 5-year mortality after hospital discharge did not significantly decrease (33% from 1960 to 1969 and 33% from 1970 to 1979). It is concluded that in the prethrombolytic era, short-term prognosis after acute myocardial infarction has improved since 1960.(ABSTRACT TRUNCATED AT 250 WORDS)