Survivorship following myocardial infarction in a contemporary Australian cohort: defining cardiac versus non-cardiac mortality.

Abstract

Background and aims: Progress in the management of myocardial infarction (MI) has led to reductions in cardiac mortality. The aim of this study was to describe the temporal trends in the relative proportions of cardiac death (CD) and non-cardiac death (NCD) in an Australian cohort with MI following in-hospital stay, then at 6 and 12 months as well as long-term follow-up.

Methods: Retrospective study at a single large tertiary referral hospital in Queensland. Outcome data were obtained from the state births/deaths/marriages registry. A total of 3464 consecutive patients with MI were included.

Results: The mean age of patients was 63.3 ± 13.8 years, 70.6% were males, and 28.2% were ST-elevation MIs. At a median follow-up of 4.5 years, there were 551 deaths (15.9%), with 200 (5.8%) classified as CD, 332 (9.6%) classified as NCD and 20 (0.5%) classified as indeterminate. In-hospital death occurred in 75 patients (2.2%). The relative proportions of cumulative CD to NCD in those with classifiable deaths (CD:NCD ratio) following in-hospital stay, then at 6, 12 and 18 months as well as long-term follow-up were: 79%:21%, 62%:38%, 53%:47% and 38%:62% respectively. Of those patients who survived their index hospitalisation, subsequent cardiac deaths accounted for only 29.7% of total deaths.

Conclusions: NCD outstrips CD at long-term follow-up in contemporary patients with MI, with the majority of deaths beyond hospital discharge attributable to NCD. The long-term risk of residual cardiac mortality was less than 30% in hospital survivors. Similar to considering the impact of cardiac events in cancer survivorship, the burden of non-cardiac events in MI survivorship needs to be considered.