ACUTE coronary syndromes (ACS) are extremely frequent and often severe in industrialised countries. A report from the AHA Statistics Committee published this year predicts that in 2009 alone almost 800,000 Americans will have suffered an ACS, and almost 200,000 others will have an asymptomatic heart attack. Thus, almost one death in five in the USA is related to acute infarction, which amounts to one death approximately every five minutes.
The situation in Europe is comparable, and therefore any improvement - even minor - in the management of ACS would be effective; even one tenth of a percent reduction in mortality would correspond to a very large number of lives saved.
There is a wide variety of fields of research and areas where management could be improved, and the numerous sessions on this subject at the ESC Congress 2009 are proof of that.
There is still room for improvement in ST elevation myocardial infarction (STEMI), where the pre-hospital phase is a particularly important stage of management, especially in the choice of reperfusion strategy. Should the treatment be given to the patient (by thrombolytic therapy), or should the patient be brought to the treatment (by delivery to the nearest cath lab)? This is an age-old question that remains hotly debated; local situations differ greatly and call for a multidisciplinary approach, based on the prior existence of a network for care and transfer to interventional centres. Which reperfusion strategy should be used when the transfer distances are very long, or in patients who present very late?
The management must be tailored to the clinical situation and to the risk level. Thus, the type of antithrombotic therapy or the use of invasive procedures is influenced by patient characteristics - and might be different in women, in octogenarians, in obese patients, in diabetics, in patients with anaemia or those with renal insufficiency.
The optimal use of anti-thrombotic agents – old or new – adapted to the thrombotic and hemorrhagic risks of each patient is also a thorny issue for which there exists no standard. The balance between efficacy and security is often hard to reach with antiplatelet or anticoagulant agents. Bleeding events, even minor, are recognised as serious adverse events and risk factors for mortality. There is a risk of hemodynamic deterioration in cases of massive bleeding, compounded by a risk of thrombosis linked to the interruption of anti-thrombotic agents, surgical intervention to control bleeding or blood transfusion.
There have been a myriad of randomised studies in the domain of acute infarction, producing a huge body of knowledge that is often difficult to apply in daily practice. The aim of clinical practice guidelines is to synthesise the best available evidence, and lay down clear recommendations for a given situation on the basis of scientific proof. The ESC issued guidelines for the management of non-ST elevation ACS in 2007, and for STEMI in 2008, among many others, and ESC guidelines are regularly updated.
Many ongoing registries also collect data in patients hospitalised for ACS. Although registries were long thought to produce only biased or debatable information, it is now acknowledged that they are the only way to provide information about clinical characteristics, the treatment that patients actually receive, and clinical evolution. It is only through registries that we can follow mortality data related to MI and learn whether new strategies and treatments validated in randomised trials are actually applicable and applied, and whether they are truly effective in reducing mortality.
The pre-hospital challenge
Only minor, or at best moderate, breakthroughs in the medical treatment of acute myocardial infarction are expected over the next decade. Organisational changes in the pre-hospital area offer the best potential to reduce death rate below 5%.
Over the past 25 years AMI mortality has decreased more than 50%. While only minor, or at best moderate, breakthroughs in its medical treatment are expected over the next decade, we have to look at organisational changes in the pre-hospital area for death rate to fall below 5%.
European hospitals admit around 1.5 million patients with ACS each year, and almost half of these patients present with ST segment elevation (STEMI). The 30 days STEMI mortality has also dropped dramatically - from 30% just 30 years ago to 10%. In clinical trials, where the sickest patients are often excluded, the death rate is as low as 5%.
This development began with the opening of dedicated coronary care units, followed by 20 years of improved drug treatments including aspirin, beta-blockers, ACE inhibitors and statins. Understanding the principles of reperfusion of the jeopardised myocardium led to the development of fibrinolytic therapy followed in the past decade by primary angioplasty.
Although new and better drugs are being developed and drug combination re
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Progress in the management of STEMI
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fined, there is less belief in major breakthroughs in this area for the coming decade. But there are still potential benefits to be gained from new anti-thrombotic drugs. Even more important is individualised treatment with these drugs, alone and in combination, to provide the optimal risk/benefit ratio for increased survival without excessive bleeds. Not have we explored the timing of these drugs to their full potential, especially in the pre-hospital phase. Recently, other mechanical methods have been proposed to limit infarct size, including both pre- and post-conditioning, but these as well as drugs which mimic conditioning need to be tested in much larger populations.
The greatest potential for obtaining a 5% or less mortality rate for the entire STEMI population is likely to arise from organisational changes. Ambitious governance is needed to coordinate efforts, starting with public awareness and alert. For those patients whose first symptom is cardiac arrest, basic resuscitation by bystanders should become the standard.
Despite an abundance of automated external defibrillators (AED) in many regions, their localisation and use is less well organised. Pre-hospital 12-lead ECGs should be obtained in all and the decision to provide reperfusion therapy made on location or through decision support via telemedicine. We have to adopt new lean principles in our organisations to assure a 75% reperfusion rate in STEMI. More STEMI patients with equivocal ECG changes should be recognised and cardiogenic shock be treated more aggressively. Financial and political disincentives to transfer STEMI patients to specialist facilities will have to be removed if we are to achieve these goals.
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