Risk stratification for ST segment elevation myocardial infarction in the era of primary percutaneous coronary intervention

Acute coronary syndromes presenting with ST elevation are usually treated with emergency reperfusion/revascularisation therapy. In contrast current evidence and national guidelines recommend risk stratification for non ST segment elevation myocardial infarction(NSTEMI) with the decision on revascularisation dependent on perceived clinical risk. Risk stratification for STEMI has no recommendation. Statistical risk scoring techniques in NSTEMI have been demonstrated to improve outcomes however their uptake has been poor perhaps due to questions over their discrimination and concern for application to individuals who may not have been adequately represented in clinical trials. STEMI is perceived to carry sufficient risk to warrant emergency coronary intervention [by primary percutaneous coronary intervention(PPCI)] even if this results in a delay to reperfusion with immediate thrombolysis. Immediate thrombolysis may be as effective in patients presenting early, or at low risk, but physicians are poor at assessing clinical and procedural risks and currently are not required to consider this. Inadequate data on risk stratification in STEMI inhibits the option of immediate fibrinolysis, which may be cost-effective. Currently the mode of reperfusion for STEMI defaults to emergency angiography and percutaneous coronary intervention ignoring alternative strategies. This review article examines the current risk scores and evidence base for risk stratification for STEMI patients. The requirements for an ideal STEMI risk score are discussed.

Acute coronary syndromes： an old age problem

The increasing population in older age will lead to greater numbers of them presenting with acute coronary syndromes （ACS）. This has implications on global healthcare resources and necessitates better management and selection for evidenced-based therapies. The elderly are a high risk group with more significant treatment benefits than younger ACS. Nevertheless, age related inequalities in ACS care are recognised and persist. This discrepancy in care, to some extent, is explained by the higher frequency of atypical and delayed presentations in the elderly, and less diagnostic electrocardiograms at presentation, potentiating a delay in ACS diagnosis. Under estimation of mortality risk in the elderly due to limited consideration for physiological tiailty, co-morbidity, cognitive/psychological impairment and physical disability, less input by cardiology specialists and lack of randomised, controlled trials data to guide management in the elderly may further confound the inequality of care. While these inequalities exist, there remains a substantial opportunity to improve age related ACS outcomes. The selection of elderly patients for specific therapies and medication regimens are unanswered. There is a growing need for randomised, controlled trial data to be more representative of the population and enroll those of advanced age with co-morbidity. A lack of reporting of adverse events, such as renal impairment post coronary angiography, in the elderly further limit risk benefit decisions. Substantial improvements in care of elderly ACS patients are required and should be advocated. Ultimately, these improvements are likely to lead to better outcomes post ACS. However, the improvement in outcome is not infinite and will be limited by non-modifiable factors of age-related risk.