Objective: This study aims to study the prognostic impact of left ventricular function on mortality and examine the effect of age on the prognostic value of left ventricular function.
Methods: We examined the myocardial ischaemia national audit project registry (2006-2010) data with a mean follow-up of 2.1 years. Left ventricular function was categorised into good (ejection fraction ⩾50%), moderate (ejection fraction 30-49%) and poor (ejection fraction <30%) categories. Cox proportional hazards models were constructed to examine the prognostic significance of left ventricular function in different age groups (<65, 65-74, 75-84 and ⩾85 years) on all-cause mortality adjusting for baseline variables.
Results: Out of 424,848 patients, left ventricular function data were available for 123,609. Multiple imputations were used to impute missing values of left ventricular function and the final sample for analyses was drawn from 414,305. After controlling for confounders, 339,887 participants were included in the regression models. For any age group, mortality was higher with a worsening degree of left ventricular impairment. Increased age reduced the adverse prognosis associated with reduced left ventricular function (hazard ratios of death comparing poor left ventricular function to good left ventricular function were 2.11, 95% confidence interval 1.88-2.37 for age <65 years and 1.28, 95% confidence interval 1.20-1.36 for age ⩾85 years). Older patients had a high mortality risk even in those with good left ventricular function. Hazard ratios of mortality for ⩾85 compared to <65 years (hazard ratio = 1.00) within good, moderate and poor ejection fraction groups were 5.89, 4.86 and 3.43, respectively.
Conclusions: In patients with acute coronary syndrome, clinicians should interpret the prognostic value of left ventricular function taking into account the patient's age.
Keywords: Acute coronary syndrome; age; left ventricular function; mortality.