Abstract 178: Acute Myocardial Infarction: Clinical Features and Performance Measures in Indigenous and Non-indigenous Australians
Authors: Tavella Rosanna , Zeitz Christopher , Arstall Margaret , Chew Derek , Worthley Matthew , Beltrame John 
Published: July 2021

Background:
Ischemic heart disease is a major contributing factor to the significant mortality and disease burden gap for Indigenous Australians. The current study is a contemporary analysis of Indigenous and non-Indigenous acute myocardial infarction (AMI) patients in regards to clinical features, in-hospital outcomes and performance measures.

Methods:
All consecutive patients undergoing coronary angiography for AMI in South Australian public hospitals from January 2012 [[Unable to Display Character: &#8211;]] December 2013 were captured. AMI patients (as per Third Universal AMI Definition) were analyzed according to ethnicity (Indigenous/Non-Indigenous). Data was maintained by the Coronary Angiogram Database of South Australia (CADOSA), a comprehensive registry compatible with the NCDR

®

CathPCI

®

Registry.

Results:
From 10,469 coronary angiograms performed, the prevalence of Indigenous patients was 4%. The frequency of AMI was higher in Indigenous (n=212) vs. Non-Indigenous (n=3636) patients (50% vs. 36%, p <0.01), despite Indigenous patients being younger by 15 years (50±12 vs. 65±13, p<0.01) and also more likely to be female (41% vs. 29%, p<0.01). Age adjusted analyses revealed a higher prevalence of comorbidities in Indigenous patients including: smoker (66% vs. 34%, p<0.01), hypertension (70% vs. 64%, p<0.01), dyslipidaemia (71% vs. 59%, p<0.01), diabetes (58% vs. 29%, p<0.01), and prior AMI (26% vs. 20%, p<0.01). There were fewer ST elevation myocardial infarcts (STEMI) (33% vs. 39%, p<0.01) but higher rates of hospital transfers (43% 25%, p<0.01) amongst Indigenous patients. Percutaneous coronary intervention (PCI) was less frequently utilized in Indigenous patients (46% vs. 51%, p<0.01), including few Indigenous STEMI patients undergoing primary PCI (18% vs. 53%, <0.01). In-hospital outcomes were similar between Indigenous and non-Indigenous patients, including bleeding complications (0.9% vs. 1.5%, p>0.05) and mortality (2.5% vs. 2.9%, p>0.05), although the relative risk of death adjusted for comorbidities was higher among Indigenous patients (2.7, (0.8-8.0) vs. 0.4, (0.1-1.3,) p>0.05). Discharge therapies were mostly similar in Indigenous vs. non-Indigenous patients including aspirin (91% vs. 84%, p>0.05), beta-blockers (75% vs. 62%, p<0.01), statin (90% vs. 83%, p<0.01), ACE-inhibitor/angiotensin receptor blocker (81% vs. 78%, p>0.05), or referral to cardiac rehab (44% vs. 48%, p>0.05).

Conclusion:
Indigenous Australians present for angiography with AMI 15 years earlier than non-Indigenous Australians. Despite this, they have a greater incidence of comorbidities, are more often transferred but PCI is less often utilised. Although in-hospital complications do not differ, there is room for improvement given a higher risk of death. Furthermore, evaluation of medication compliance and access to medications post discharge may provide further insight into disease burden.