Cardiology networks: improving the management of acute coronary syndromes

Not only is there a troubling disparity in cardiac health between urban and rural communities,1 there is now considerable evidence that patients who suffer a suspected heart attack (acute coronary syndrome [ACS]) in smaller hospitals in rural areas may not receive state-of-the-art coronary reperfusion treatment2 or optimal care in the medical management of their ACS.3 There is overwhelming evidence that the best treatment for patients with ST-elevation myocardial infarction (STEMI) is coronary reperfusion as soon as possible4 and that the outcome for non-STEMI is better if coronary angiography is performed during the initial hospital admission.5 Unfortunately, timely cardiac catheterisation in a centre capable of percutaneous coronary intervention (PCI) is an ideal not always available. Long distances from rural centres to advanced cardiac care facilities is an Australian reality, and it is unrealistic to hope for sophisticated cardiac facilities in every country town, although there has been successful establishment of regional cardiac facilities in some states. Certain major rural hubs, such as Wagga Wagga, have had cardiac catheterisation facilities since 1997, and many of these centres have been PCI capable for some time.

One logical approach to facilitating appropriate transfer of patients with an ACS to PCI-capable centres is to establish cardiac care networks that enable small rural sites to receive immediate advice on managing patients with an ACS and to arrange seamless transfer to a PCI-capable centre.

In this issue of the Journal, Tideman and colleagues report on the beneficial effect of a cardiac network to support patients who suffer an acute coronary event in rural South Australia.6 The elements of the network are relatively simple, but the work to implement a successful network such as this is enormous.

The key message of the study is that there has been an improvement in the trends for rural severity-adjusted 30-day ACS mortality since the introduction of the Integrated Cardiovascular Clinical Network (ICCNet). After adjustment for temporal improvement in MI outcome, availability of immediate cardiac support was associated with a highly statistically significant 22% relative odds reduction in 30-day mortality over a 9-year period.

The improving mortality coincided with increased use of transfer for coronary angiography. However, the limitations of a retrospective study need to be recognised and other possible influences on improved outcome cannot be ruled out. Clearly, more prospective evaluation of these initiatives is needed before concluding that the ideal model of management for rural patients with an ACS has been reached.

It is of note that the rate of coronary angiography for patients with an ACS in rural South Australia was only 28% and was still under 50% for all-comers in South Australia during the study period. While the rates of STEMI are not included in the report, it would be expected that the proportion of patients with STEMI having angiography would have increased significantly, since it has been generally understood for over a decade7,8 that outcomes among more conservatively treated groups of patients with STEMI will be less favourable.

Although this study explored the impact of the ICCNet on the rates of transfer for invasive procedures, what is missing are any data on thrombolysis for STEMI in these patients. It would be critical that any centralised network, particularly for patients who are more than an hour by road or other forms of transport, is advising on all reperfusion strategies, not just appropriateness for transfer to a metropolitan centre with the purpose of primary or salvage PCI. The recent STREAM study9 showed very good outcomes for STEMI patients treated with thrombolysis if primary PCI was not available within 90 minutes. The best outcomes will occur when urgent post-lysis transfer can permit salvage PCI for non-responders.

In summary, this study highlights the importance of risk stratification and timely transfer of selected patients for angiography and revascularisation as needed, and the network serves as a model for other states, particularly those without decentralised invasive cardiac facilities and regionally resident specialists.

It should be our objective nationally that patients with STEMI have access to the most timely means of reperfusion, be it thrombolysis or primary PCI, and that patients with non-STEMI with moderate to high risk be recommended for transfer and angiography and to be given antiplatelet agent and anticoagulant therapy during the same admission as their presentation. Cardiology networks facilitating early expert care and appropriate transfer to tertiary care are an important advance in the management of patients with acute coronary syndromes.