Acute coronary syndromes in insulin treated diabetics, elderly and female patients: remaining gaps in EMS activation, therapy and clinical outcomes

Triage of chest pain patients calling the emergency medical system (EMS) has to rely entirely on the interpretation of the symptoms by medical dispatchers. The presence of associated symptoms may help in assessing the need for urgent medical transportation. In a large prospective observational multicenter study performed in Sweden, chest pain associated with cold sweat, jaw pain or nausea was significantly more frequent in patients with a ST elevation myocardial infarction (STEMI) than in patients with non-ST elevation myocardial infarction (NSTEMI).1 Presence of these associated symptoms should therefore stimulate EMS dispatchers to give chest pain patients priority for urgent ambulance transportation to a primary percutaneous coronary intervention (PCI) capable hospital as they have a much higher likelihood to suffer a STEMI. Complete ST-segment resolution is a well-established marker of successful reperfusion after primary PCI in STEMI patients. In a post-hoc analysis of the pre-hospital ATLANTIC (Administration of Ticagrelor in the catheterization laboratory or in the Ambulance for New ST elevation myocardial Infarction to open the Coronary artery) trial complete ST-segment resolution was associated with an improved clinical outcome with a much lower 30-day composite major adverse cardiovascular and cerebrovascular events, definite stent thrombosis and mortality rates.2 Diabetes mellitus and long time-intervals between symptoms and the first pre-hospital electrocardiogram recording were independent predictors of poor reperfusion. Diabetes mellitus also has a marked negative impact on the long-term outcome of STEMI patients. Data from the FAST-MI 2005 registry (NCT00673036) show that insulin treatment on discharge was associated with a markedly increased all-cause 5-year mortality.3 These results suggest that insulin treatment may have important long-term intrinsic harmful effects after myocardial infarction in high-risk diabetic patients. The impact of insulin-treated diabetes on cardiovascular outcomes following STEMI complicated by heart failure and/ or left ventricular systolic dysfunction was also studied by the High-Risk Myocardial Infarction Database Initiative on a very large prospective patient cohort derived from the databases of 4 large randomised trials.4 Insulin-treated diabetes had higher event rates than patients with diabetes under oral treatments and patients without diabetes. More frequent comorbidities and complex atherosclerotic disease in insulin-treated diabetes patients preclude any causal relation between insulin treatment and cardiovascular outcomes. Elderly STEMI patients are less frequently treated by evidence-based reperfusion therapies and this conservative treatment strategy is associated with an increased mortality. This was again demonstrated by an analysis of the administrative data on almost 300,000 STEMI patients extracted from the Minimum Basic Data Set of the Spanish public health system covering all hospital discharges between 2004 and 2013.5 However, during the study period the use of PCI in elderly STEMI patients increased progressively what was associated with a progressive reduction of crude mortality. A prospective multicentre study performed in Spain showed that octogenarian women presenting with non-ST-segment elevation acute coronary syndromes are compared to men at increased risk of hospital readmission during the first 6 months.6 Frailty in women was more common than in men and was associated with a marked increase in mortality. Female sex and South Asian race have been associated with poor clinical outcome after primary PCI for STEMI. However, in a prospective study performed at a large UK tertiary center, mortality and incidence of major adverse cardiovascular events 1 year after primary PCI were not greater in women and south Asian patients, after adjustment for cardiovascular risk factors including age, which was the strongest predictor of both complications.7 Also in China women experience a worse clinical outcome than men up to one year after acute myocardial infarction with an increased all cause and cardiac mortality, a poorer health-related quality of life, a worse functional status and more daily/weekly angina.8 After adjustment for age the differences between men and women decreased but remained unchanged for general clinical health status. Meanwhile, In Switzerland there are no gender differences anymore in the timely delivery of primary PCI.9 Nevertheless, there remain gender differences in total ischemic time due to higher patient delays in women, suggesting that female STEMI patients less urgently seek medical help. In an accompanying editorial it is proposed to implement more sex-specific knowledge and recommendations in our acute coronary syndromes guidelines in order to stop higher mortality and complication rates in our female population.10