Long Term Survival Rate and Prognostic Factors of Acute Myocardial Infarction of Elderly Patients

ABSTRACT

BACKGROUND: Acute myocardial infarction (AMI) is a common disease in older patients, and common cause of death in this age group. In the United State, more than 670,000 persons are hospitalized annually for an acute myocardial infarction, 60% of these persons are more than 65 years of age and one third are above 75 years of age. above 65 years of age and 60% above 75 years of age. Also in Korea, AMI has been increased and being a major cause of death. Especially in elderly patients, more intensive care is required, because they have more risk factors and show high mortality. For will decrease unnecessary treatment on low risk group and will do more intensive management on high risk group. This study was performed, therefore, to provide the clinical features, prognosis and prognostic factors of AMI in Korean elderly patients. METHODS: To identify the long term survival rate and prognostic factors of acute myocardial infarction of elderly persons (above 65 year old) in Korea, total 358 patients who presented between Jan. 1980 and Dec. 1997 at Seoul National University Hospital were followed for an average of 92 months. 151 patients were died during follow up period, 63 patients lost, and 144 patients were alive till the end point of the study. RESULTS: Overall survival rates (+/-standard error) were 82.1+/-2.0, 79.6+/-2.2, 76.7+/-2.3, 72.2+/-2.5, 67.4+/-2.7, 62+/-3.0, 56.9+/-3.2% at 1, 6, 12, 24, 36, 48, 60 months. In univariate analysis, old age, female, presence of history of diabetes, higher degree of Killip class, lower ejection fraction on echocardiography or gated blood pool scan, lower total cholesterol level on the time of AMI proved as poor prognostic factors of AMI with statistical significance (p<0.05). BMI, history of hypertension, myocardial infarction and angina, peak CK level, infarct site on ECG, existence of Q-wave on ECG, larger extent of coronary artery disease, residual ischemia on treadmill test or MIBI scan, patency of infarct related artery, and HDL and LDL-cholesterol level on the time of AMI, total, HDL- and LDL-cholesterol at least 3 months after AMI did not show statistical significance. In multivariate analysis, Killip class III, IV and ejection fraction on echocar-diography are proved as independent prognostic factors of AMI with statistical significance (p<0.05). CONCLUSION: The mortality of elderly AMI is composed of two component. At acute phase, within 1 month, the mortality reaches to about 18 %, and at chronic phase, after 1 month from AMI, mortality increases each 5% a year for 5 years. The other conclusion is elderly patients who have poor left ventricular systolic functions shows higher mortality.