Clinical significance of renal haemodynamics in acute myocardial infarction

Does arterial hypotension due to cardiogenic shock in older patients lead to functional oliguria or to acute renal failure?

OBJECTIVES

Reports indicate some differences in the outcome of prolonged arterial hypotension due to cardiogenic shock: acute renal failure in older and more often functional oliguria in younger patients. The aim of the study is to analyze prolonged hypotension due to acute myocardial infarction in older and younger patients and to answer the question: does prolonged hypotension, due to acute myocardial infarction, lead to acute renal failure or to functional oliguria in older patients.

METHODS

During a 10-year observation, a study of 11 older (> 65 years) and 7 younger patients (< 65 years), suffering from acute myocardial infarction and cardiogenic shock, is presented: clinical data and laboratory: diuresis, sodium in urine, creatinine urine/plasma ratio, urine osmolality, osmolality urine/plasma ratio, renal failure index and fractional excretion of filtered sodium.

RESULTS

In 7 older and 5 younger patients, natriuresis indicated acute renal failure. The ratio of creatinine in urine and plasma in 3 older and 5 younger indicated functional oliguria; in 3 older and 1 younger, acute renal failure; and in 5 older and 1 younger, borderline values. In 7 older and 2 younger, the values of urine osmolality were in the range of functional oliguria and, in 4 older and 5 younger, borderline values between those two parameters, as the osmolality quotient in urine and plasma. The values of the renal failure index in all older and younger patients was lower than 3.0 (in 6 older and 3 younger, lower than 1.0) indicated functional oliguria, as the fractional excretion of filtered sodium Of 9 older patients who died, 5 were examined by autopsy, and 3 out of 4 younger who died. All had myocardial fibrosis and scars, apart from recent myocardial infarction and coronary atherosclerosis. In 2 older, acute tubular necrosis was found while in 2 no renal changes were found. In 2 younger, no renal changes were found and in 1 showed disseminated intravascular coagulation.

CONCLUSION

Acute renal failure due to cardiogenic shock in older patients is functional, or is rare renal.

Coronary prognostic index for the Chinese

A coronary prognostic index (CPI) for the prediction of mortality of patients with acute myocardial infarction (AMI) has been constructed with data from 644 Chinese patients in Hong Kong. According to this CPI, patients with AMI could be divided into subgroups with increasing hospital mortality from 1.6% to 100%, depending on their ages, blood pressure, heart size, serum urea level, positions and types of infarcts, the presence of pulmonary congestion and cardiac dysrhythmia in the initial three days. This simple and convenient CPI could be useful for the objective assessment and stratification of AMI in the Chinese, as well as in many other developing countries in the Asian-Pacific region.