Objective To review, inventory and compare available diagnostic tools and investigate which tool has the best performance for prehospital risk assessment in patients suspected of non-ST-segment elevation acute coronary syndrome (NSTE-ACS). Methods Systematic review and meta-analysis. Medline and Embase were searched up till 1 April 2021. Prospective studies with patients, suspected of NSTE-ACS, presenting in the primary care setting or by emergency medical services (EMS) were included. The most important exclusion criteria were studies including only patients with ST-elevation myocardial infarction and studies before 1995, the pretroponin era. The primary end point was the final hospital discharge diagnosis of NSTE-ACS or major adverse cardiac events (MACE) within 6 weeks. Risk of bias was evaluated by the Quality Assessment of Diagnostic Accuracy Studies Criteria. Main outcome and measures Sensitivity, specificity and likelihood ratio of findings for risk stratification in patients suspected of NSTE-ACS. Results In total, 15 prospective studies were included; these studies reflected in total 26 083 patients. No specific variables related to symptoms, physical examination or risk factors were useful in risk stratification for NSTE-ACS diagnosis. The most useful electrocardiographic finding was ST-segment depression (LR+3.85 (95% CI 2.58 to 5.76)). Point-of-care troponin was found to be a strong predictor for NSTE-ACS in primary care (LR+14.16 (95% CI 4.28 to 46.90) and EMS setting (LR+6.16 (95% CI 5.02 to 7.57)). Combined risk scores were the best for risk assessment in an NSTE-ACS. From the combined risk scores that can be used immediately in a prehospital setting, the PreHEART score, a validated combined risk score for prehospital use, derived from the HEART score (History, ECG, Age, Risk factors, Troponin), was most useful for risk stratification in patients with NSTE-ACS (LR+8.19 (95% CI 5.47 to 12.26)) and for identifying patients without ACS (LR−0.05 (95% CI 0.02 to 0.15)). Discussion Important study limitations were verification bias and heterogeneity between studies. In the prehospital setting, several diagnostic tools have been reported which could improve risk stratification, triage and early treatment in patients suspected for NSTE-ACS. On-site assessment of troponin and combined risk scores derived from the HEART score are strong predictors. These results support further studies to investigate the impact of these new tools on logistics and clinical outcome. Funding This study is funded by ZonMw, the Dutch Organisation for Health Research and Development. Trial registration number This meta-analysis was published for registration in PROSPERO prior to starting (CRD York, CRD42021254122).

Objective Prehospital risk stratification and triage are currently not performed in patients suspected of non-ST-segment elevation acute coronary syndrome (NSTE-ACS). This may lead to prolonged time to revascularisation, increased duration of hospital admission and higher healthcare costs. The preHEART score (prehospital history, ECG, age, risk factors and point-of-care troponin score) can be used by emergency medical services (EMS) personnel for prehospital risk stratification and triage decisions in patients with NSTE-ACS. The aim of the current study was to evaluate the effect of prehospital risk stratification and direct transfer to a percutaneous coronary intervention (PCI) centre, based on the preHEART score, on time to final invasive diagnostics or culprit revascularisation. Methods Prospective, multicentre, two-cohort study in patients with suspected NSTE-ACS. The first cohort is observational (standard care), while the second (interventional) cohort includes patients who are stratified for direct transfer to either a PCI or a non-PCI centre based on their preHEART score. Risk stratification and triage are performed by EMS personnel. The primary endpoint of the study is time from first medical contact until final invasive diagnostics or revascularisation. Secondary endpoints are time from first medical contact until intracoronary angiography (ICA), duration of hospital admission, number of invasive diagnostics, number of inter-hospital transfers and major adverse cardiac events at 7 and 30 days. Results A total of 1069 patients were included. In the interventional cohort (n=577), time between final invasive diagnostics or revascularisation (42 (17–101) hours vs 20 (5–44) hours, p<0.001) and length of hospital admission (3 (2–5) days vs 2 (1–4) days, p=0.007) were shorter than in the observational cohort (n=492). In patients with NSTE-ACS in need for ICA or revascularisation, healthcare costs were reduced in the interventional cohort (€5599 (2978–9625) vs €4899 (2278–5947), p=0.02). Conclusion Prehospital risk stratification and direct transfer to a PCI centre, based on the preHEART score, reduces time from first medical contact to final invasive diagnostics and revascularisation, reduces duration of hospital admission and decreases healthcare costs in patients with NSTE-ACS in need for ICA or revascularisation. Trial registration NCT05243485.

Objectives Recently, drug-coated balloons (DCB) have emerged as a promising alternative for side branch treatment in coronary bifurcation lesions, in combination with drug-eluting stent (DES) implantation in the main vessel, the hybrid DCB approach. We aimed to evaluate clinical outcomes in patients treated with the hybrid DCB approach and to compare this strategy with other bifurcation techniques. Design A systematic review and meta-analysis. Data sources MEDLINE and EMBASE were searched up until January 2025. Eligibility criteria We included randomised controlled trials and observational studies investigating clinical outcomes in patients treated with the hybrid DCB approach for coronary bifurcation lesions. Data extraction and synthesis Two independent reviewers extracted data and assessed the risk of bias. The outcome of interest was the combined endpoint of cardiac death, myocardial infarction (MI) or target lesion revascularisation (TLR) at the longest available follow-up. Crude event rates, stratified by treatment strategy, were provided for the overall incidence of the primary endpoint. Furthermore, we conducted meta-analyses on the combined endpoint, comparing different bifurcation percutaneous coronary intervention (PCI) strategies. The certainty of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation tool. Results 13 studies, consisting of 2393 patients, were included in our systematic review. Investigated techniques were the hybrid DCB approach in all studies, and a two-stent strategy or the combination of DES in main vessel and balloon angioplasty (BA) in the side branch as potential comparators. Median follow-up duration was 12 months (IQR 7.5–12). The combined endpoint of cardiac death, MI or TLR was found in 5.6% in the hybrid DCB group, 15.4% in the two-stent group and in 10.0% in the BA group. The pooled analyses, including three and two studies, respectively, showed that the hybrid DCB approach was associated with a lower risk of the composite endpoint of cardiac death, MI or TLR when compared with a two-stent strategy (7.9% vs 15.4%; risk ratio (RR): 0.53; 95% CI 0.33 to 0.85) and compared with BA in the side branch (5.6% vs 10.0%; RR: 0.57; 95% CI 0.37 to 0.88). The certainty of the evidence was graded as very low. Conclusion The results of this systematic review and meta-analysis suggest that the hybrid DCB approach is a feasible and promising treatment approach for bifurcation lesions, when compared with other bifurcation PCI strategies. However, the results should be interpreted cautiously as the certainty of evidence was graded as very low, underlining the importance of larger trials to confirm these findings. Trial registration number CRD420250651469.

The timely revascularization of an occluded coronary artery is the cornerstone of treatment in patients with ST-elevation myocardial infarction (STEMI). As essential as this treatment is, it can also cause additional damage to cardiomyocytes that were still viable before reperfusion, increasing infarct size. This has been termed “myocardial reperfusion injury”. To date, there is still no effective treatment for myocardial reperfusion injury in patients with STEMI. While numerous attempts have been made to overcome this hurdle with various experimental therapies, the common denominator of these therapies is that, although they often work in the preclinical setting, they fail to demonstrate the same results in human trials. Hypothermia is an example of such a therapy. Although promising results were derived from experimental studies, multiple randomized controlled trials failed to do the same. This review includes a discussion of hypothermia as a potential treatment for myocardial reperfusion injury, including lessons learned from previous (negative) trials, advanced techniques and materials in current hypothermic treatment, and the possible future of hypothermia for cardioprotection in patients with STEMI.

Objectives: Most patients presenting with chest pain in the emergency medical services (EMS) setting are suspected of non-ST-elevation acute coronary syndrome (NSTE-ACS). Distinguishing true NSTE-ACS from non-cardiac chest pain based solely on the ECG is challenging. The aim of this study is to develop and validate a convolutional neural network (CNN)-based model for risk stratification of suspected NSTE-ACS patients and to compare its performance with currently available prehospital diagnostic tools. Methods: For this study, an internal training cohort and an external validation cohort were used, both consisting of suspected NSTE-ACS patients. A CNN (ECG interpretation by CNN (ECG-AI)) was trained and validated to detect NSTE-ACS. The diagnostic value of ECG-AI in detecting NSTE-ACS was compared with on-site ECG analyses by an EMS paramedic (ECG-EMS), point-of-care troponin assessment and a validated prehospital clinical risk score (prehospital History, ECG, Age, Risk factors and POC-troponin (preHEART)). Results: A total of 5645 patients suspected of NSTE-ACS were included. In the external validation cohort (n=754), 27% were diagnosed with NSTE-ACS. ECG-AI had a better diagnostic performance than ECG-EMS (area under the curve (AUROC) 0.70 (0.66 to 0.74) vs AUROC 0.65 (0.61 to 0.70), p=0.045) for diagnosing NSTE-ACS. The overall diagnostic accuracy of preHEART was AUROC 0.78 (0.74 to 0.82) and superior compared with ECG-AI (p=0.001). Incorporating ECG-AI into preHEART led to a significant improvement in diagnostic performance (AUROC 0.83 (0.79 to 0.86), p<0.001). Discussion: Correctly identifying patients who are at low risk for having NSTE-ACS is crucial for optimal triage in the prehospital setting. Recent studies have shown that these low-risk patients could potentially be left at home or transferred to a general practitioner, leading to less emergency department overcrowding and lower healthcare costs. Other studies demonstrated better overall diagnostic performance compared with our artificial intelligence (AI) model. However, these studies were aimed at a study population with a high prevalence of occlusive myocardial infarction, which could explain the differing levels of diagnostic performance. Conclusion: Integrating AI in prehospital ECG interpretation improves the identification of patients at low risk for having NSTE-ACS. Nonetheless, clinical risk scores currently yield the best diagnostic performance and their accuracy could be further enhanced through AI. Our results pave the way for new studies focused on exploring the role of AI in prehospital risk-stratification efforts.