Have a HEART! Strategies to identify low-risk cardiac patients in the prehospital environment
The History, Electrocardiogram (ECG), Age, Risk factors and Troponin (HEART) score is widely used in emergency departments to categorise risk in patients with chest pain that is suspicious for a myocardial infarction, and to help identify those at low risk who are appropriate for early discharge. Studies in the prehospital environment have evaluated the low-risk HEART score using a point-of-care troponin assay but have not demonstrated the sensitivity and negative predictive value (NPV) to safely identify patients who could be managed without hospital transfer.
This study undertook secondary analysis of data collected in an earlier prospective cohort study to try to identify lower-risk patients who could be managed outside hospital. Data were originally collected in the Ambulance Cardiac Chest Pain Evaluation in Scotland Study (ACCESS), where paramedics prospectively enrolled patients with suspected acute coronary syndrome without diagnostic ST-segment elevation on the ECG. A HEAR (without Troponin) score was recorded contemporaneously, and a prehospital blood sample was obtained for subsequent cardiac troponin testing. Troponin was tested at the emergency department using the Siemens ADVIA Centaur Ultra contemporary cardiac troponin I assay, and surplus blood was sent for analysis with Abbott ARCHITECT high-sensitivity troponin I assay. The prehospital HEART score was calculated separately for both the contemporary and high-sensitivity cardiac troponin assays. The primary outcome measure was Major Adverse Cardiac Events (MACE) at 30 days (as defined in the study). A HEART score of ≤3 and ≥7 represented low- and high-risk, respectively (see article for calculation of HEART score).
A total of 960 patients were eligible for analysis (mean age 64 years (SD: 15), 42% women). A HEART score of ≤3 with either assay identified one in three patients as low risk, but the sensitivity and NPV to rule out MACE, or a composite outcome of myocardial infarction or cardiac death, at 30 days was too low to be safely used in practice.
Early GTN in acute ischaemic stroke—probably not!
In patients presenting with acute ischaemic stroke, high blood pressure (BP) is common and associated with a worse clinical outcome. Recent trials in acute ischaemic stroke assessing BP-lowering medications have produced conflicting results and methods for managing elevated BP in this patient group remain unclear. Nitric oxide (NO) donors, including glyceryl trinitrate (GTN), have properties beyond lowering BP, such as improved cerebral perfusion, neuroprotection, and anti-inflammation, that may be useful in acute stroke. In preclinical studies of permanent cerebral ischaemia models, NO donors reduced infarct size and increased cerebral blood flow, but only when given early after stroke onset.
This study sought to assess the safety and efficacy of GTN in the prespecified subgroup of patients who had an ischaemicw stroke within the Rapid Intervention with Glyceryl trinitrate in Hypertensive stroke Trial-2 (RIGHT-2). RIGHT-2 was an ambulance-based multicentre sham-controlled blinded-endpoint study with patients randomised within 4 hours of onset. The primary outcome was function (death and dependency) assessed using the modified Rankin Scale (mRS, scores of 0=normal to 6=died) measured at day 90. A number of secondary measures were also evaluated.
In total, 597 patients had a final diagnosis of ischaemic stroke and were included in the study (demographics available in the full article). Analysis found that BP fell over the 4 days of treatment in both randomised groups, with GTN being more effective than sham treatment at hospital admission and at day 2. However, BP did not differ between groups after day 2. GTN did not influence death and dependency (GTN 3 [2, 5] vs sham 3 [2, 5], adjusted common OR for increased dependency 1.15, 95% CI 0.85 to 1.54, p=0.36). In this study, administration of GTN in the ambulance did not improve clinical outcomes.