Triage, diagnosis and management of acute chest pain syndromes, atypical and high-risk subtypes of acute coronary artery syndromes

Patients presenting with chest pain suspected of an acute coronary syndrome represent a major challenge as inadvertent hospital discharge may have important consequences. The HEART score is a simple and effective tool to detect low risk patients who are eligible for early discharge. In a large retrospective study in this issue the HEART score performed equally good among Caucasian and different Asian ethnic groups.1 However, in contrast with earlier studies2 –5 the negative predictive value was lower (95% instead of 99 to 100%) with a higher incidence of major adverse cardiac events indicating that further studies are needed to determine the safety of discharging low risk patients solely based on the HEART score. Performing a O & 1 hour serial sampling of a high sensitivity cardiac troponin along the calculation of the HEART score may possibly result in more accurate detection of a low risk group of chest pain patients that safely can be discharged from the emergency department.6 Acute aortic syndromes are an important differential diagnosis in patients presenting with acute chest pain. The results of a recent large multicenter registry performed in 26 tertiary Spanish hospitals with cardiac surgery show that improved diagnostics and surgical treatment have not led to improved clinical outcomes.7 It is hypothesized that the creation of regional aortic surgery centers with highly specialized teams may help to lower the mortality rate. There is a greater awareness for spontaneous coronary artery dissection (SCAD), a less rare than previously thought condition and a diagnosis that should not be missed in predominantly young female patients presenting with acute ischemic symptoms as the therapeutic management and clinical course is different from that of the acute coronary syndromes caused by the complications of coronary atherosclerosis at a later age.8,9 Coronary computed tomography angiography (CCTA) which is increasingly utilized to rule out coronary atherosclerotic coronary artery disease in low risk patients presenting with acute chest pain to the emergency department, could also be useful in the diagnosis and assessment of SCAD. In three patients seen at the Mayo clinic SCAD was initially not detected on CCTA and was only identified retrospectively after an invasive coronary angiography was performed.8 This small series demonstrates that CCTA does not allow to rule out SCAD and that invasive coronary angiography should be preferred as initial diagnostic test in chest pain patients with features suspected for SCAD. Interventional treatment of SCAD is technically challenging and frequently results in suboptimal outcomes even if intracoronary ultrasound or optical coherence tomography are used for guidance. Large intramural hematomas may on the other hand resolve completely under conservative medical treatment. Therefore, it remains unclear what the best initial therapeutic strategy is in patients with SCAD. In a systematic literature review and meta-analysis comparing a conservative management with an early interventional revascularization strategy no significant differences in mortality, incidence of myocardial infarction or SCAD recurrence were observed.10 However, an early interventional approach was associated with an increased risk for repeat target vessel revascularization. This study confirms the prevailing recommendation to treat SCAD preferably conservatively unless ongoing ischemia necessitates interventional treatment. Kounis syndrome is another rare type of acute coronary syndrome that is triggered by allergic, hypersensitivity or anaphylactoid reactions to a drug or other substances. The pathophysiology of this syndrome is based on the release cytokines by activated mast cells that leads to coronary vasospasm, atheromatous plaque erosion or rupture or stent thrombosis. A Kounis syndrome with coronary spasm secondary to cefuroxime injection complicated by cardiogenic shock is reported together with a recent review of the literature.11 There is an increasing interest in the cardiac complications of cancer with the development of a new subspecialty in cardiology and the proposal to organize multidisciplinary cardio-oncology teams and services.12,13 Conversely, the prevalence of cancer seems much higher in patients with ischemic heart diseases: in a recent sub-analysis of the BLEEMACS registry the prevalence of cancer in patients with acute coronary syndrome undergoing a percutaneous coronary intervention was much higher (6.3%) than in the general population (0.38%).14 The patients with cancer showed a much higher risk of both bleeding and ischemic events during a 1-year follow-up. Although evidence-based therapy appeared equally effective as in non-cancer patients, there was an important gap in the application of guideline recommended therapy in cancer patients with an acute coronary syndrome. Similar findings were observed in a large registry of ST elevation myocardial infarction (STEMI) patients in Switzerland: STEMI patients with a history of cancer were less likely to receive guideline recommended treatment and had worse in-hospital outcomes than non-cancer patients.15 The cornerstone of the treatment of acute coronary syndromes is early coronary revascularization under the protection of potent antithrombotic drugs both during the intervention and the convalescence up to one year after the acute phase.16 Acute coronary syndromes patients with preexisting chronic anemia may suffer from occult blood loss that may be aggravated by the potent dual antiplatelet therapy after coronary intervention. In a small study from Israel moderate or severe chronic anemia in patients with acute coronary syndrome undergoing coronary angiography or percutaneous coronary intervention was associated with an increased risk of bleeding in the first 6 months.17 This was however not associated with an increase in mortality or re-infarction. In patients with moderate or severe chronic anemia all measures should therefore be taken to minimize and prevent bleeding complications by using the radial approach and adjustment of the antithrombotic treatment. Acute coronary syndromes patients with prior cerebrovascular and peripheral artery disease constitute another high-risk group. These patients frequently have more extensive and severe coronary artery disease and fear of bleeding complications may lead to less application of guideline recommended antithrombotic therapies. Data from a very large Portuguese national registry show that patients with a prior history of stroke or transient ischemic attack and/or peripheral artery disease received less frequently guideline recommended medical therapy and coronary interventions and have an up to four times higher risk for the composite endpoint of in-hospital death, re-infarction and stroke.18 Delirium is a frequent in-hospital complication in elderly patients and is associated with poor clinical outcome. Also in elderly patients admitted to the intensive cardiac care unit (ICCU) delirium develops frequently and is associated with a marked increase of in-hospital, 30-day and 6-month mortality, irrespective the time of delirium onset.19 Many patients admitted to the ICCU develop multi-organ failure that frequently necessitates invasive mechanical ventilation during a longer period. In this situation sedation is frequently needed for patient-ventilator synchrony, reduction of work of breathing, and patient comfort. Sedation is also mandatory in patients undergoing targeted temperature management after cardiac arrest. In an educational review the indications and use of sedatives in the ICCU is discussed in detail.20