A triptych on acute cardiovascular care

This issue provides a triptych on acute cardiovascular care.

A first part brings several studies on the management of patients presenting with chest pain to the emergency department (ED). Sorting out the small minority of patients with an acute coronary syndrome without missing a single one from a large number of patients presenting with most often atypical chest pain to the ED remains a significant challenge. The advent of more specific and sensitive biomarkers has improved significantly the accuracy of the diagnostic algorithms used for risk stratifying patients with chest pain.

Copeptin, the c-terminal end of arginine vasopressin, is secreted very early in acute myocardial infarction (AMI) patients, whereas cardiac troponin (cTn) rises later after the onset of chest pain. Measurement of copeptin in conjunction with cTn adds incremental accuracy in the early rule-out of MI compared to accelerated diagnostic pathways using cTn as a sole biomarker. A sub-analysis of the Copeptin Helps in the Early Detection of Patients with Acute Myocardial Infarction (CHOPIN) trial, reports a difference in AMI rule-out by copeptin between Blacks and Caucasians, with increased negative predictive value and sensitivity in the black patients at a cut-off of 14 pmol/l. ¹

However, since the advent of high sensitivity cTn (hs-cTn) assays, the need for combined biomarker testing is markedly reduced if not wholly obviated. Introduction in routine clinical practice at a large London hospital of a 0-hour ‘rule-out’ and ‘rule-in’ algorithm based on a single hs-cTn measurement on admission enabled rapid triage of 48% of patients as low-risk and to rule-in 5% as high-risk. ²

A large meta-analysis on the accuracy of diagnostic tests for patients presenting with chest pain to the ED confirms the advantage of rapid rule-out algorithms using hs-cTn assays. Among the non-invasive ischemia tests used in low-risk patients without increased hs-cTn, coronary computed tomography angiography scored the highest diagnostic accuracy while exercise electrocardiogram (ECG) testing the lowest. ³

Another large prospective study at a large English hospital compared the efficacy and safety of a rule-out algorithm based on a single hs-cTn measurement and a non-ischemic ECG with established clinical risk scores. ⁴ AMI and MACE during early follow-up could be ruled out with great certainty by a HEART score ≤3 and an admission test result of hs-cTn at limits of detection.

Admission with chest pain in the week is safer than during the weekend. A literature review shows that there is a small weekend effect on mortality in patients admitted with an acute coronary syndrome. ⁵

An educational review discussing in detail the pathophysiology and treatment of the ischemia-reperfusion syndrome ⁶ is the masterpiece in the middle part of this issue. A better understanding of the mechanisms leading to this syndrome is of great importance as its development significantly curtails the benefits of reperfusion therapy for ST-elevation myocardial infarction.

The third part of this issue is focusing on the use of imaging in acute cardiovascular care.

Cardiac magnetic resonance (CMR) imaging provides detailed morphological information on the extent and transmurality of myocardial infarctions and is also useful in the assessment of pericardial effusions (PE) complicating an AMI. A clinical study compared the clinical, angiographic and CMR characteristics of patients with AMI complicated by an incomplete myocardial rupture (IMR) or a moderate-severe pericardial effusion. ⁷ IMR is generally silent and occurs in younger patients with smaller infarct size than those with pericardial effusion. Both groups of patients present late and are often untreated with reperfusion therapy. This study suggests, therefore, to perform CMR imaging assessment in AMI patients with delayed admission, particularly in the absence of reperfusion, to rule out an IMR.

Coronary computed tomography angiography (CCTA) could be helpful in the assessment of acute spontaneous coronary artery dissection (SCAD), a frequent cause of acute coronary syndrome in young women. A small retrospective study in SCAD patients learns that abrupt luminal stenosis and intramural hematoma are the most common CCTA features of SCAD. ⁸ As the clinical experience with CCTA in SCAD is very limited, invasive coronary angiography remains the first-line diagnostic method to assess a patient with an acute coronary syndrome and possible SCAD.

Transesophageal echocardiography (TEE) has superior sensitivity in the detection of vegetations and the diagnosis of infective endocarditis but is more invasive than transthoracic echocardiography. A study in patients with Staphylococcus aureus bacteremia assessed the Palraj scoring system used for the detection of patients at high risk for infective endocarditis and as a guide for selective use of TEE. ⁹ Inclusion of intravenous drug abuse as a variable improved the score’s sensitivity and specificity. The results of this study recommend the use of the modified Palraj scoring system in the diagnostic evaluation of patients with Staphylococcus aureus bacteremia.