Flecainide to Prevent Atrial Arrhythmia after Patent Foramen Ovale Closure, the AFLOAT Study: A Randomized Clinical Trial.

BACKGROUND: The real incidence of atrial arrhythmia (AA) after patent foramen ovale (PFO) closure and whether this complication can be prevented remain unknown. This study assessed if flecainide is effective to prevent AA during the first 3 months after PFO closure, and if 6 months treatment by flecainide is more effective than 3 months to prevent AA after PFO closure. METHODS: AFLOAT is a prospective, multicentre, randomized, open-label, superiority trial with a blind evaluation of all the endpoints (PROBE design). Patients were randomized in a 1:1:1 ratio after PFO closure to receive flecainide (150 mg once a day in a sustained-release (SR) dose) for 3 months, flecainide (150 mg od SR dose) for 6 months, or no additional treatment (standard-of-care) for 6 months. The primary endpoint was the percentage of patients with at least one episode AA (≥30s) recorded within 3 months after PFO closure on long-term monitoring with an insertable cardiac monitor (ICM). The secondary endpoint was the percentage of patients with at least one episode of AA (≥30s) recorded with ICM during the 3-6 months period after PFO closure. RESULTS: 186 patients were included (mean age 54 years, male 68.8%) and AA (≥30s) occurred in 53 (28.5%) patients during the 6-month follow-up; 86.8% of these AA events occurred in the first month after PFO closure. The primary outcome occurred in 33/123 (26.8%) and 16/63 (25.4%) patients receiving flecainide for at least 3 months or standard of care, respectively [Risk Difference (RD) 1.4%; 95% confidence interval (CI) -12.9% to 13.8%, NS]. The secondary endpoint occurred in 3/60 (5.0%), 4/63 (6.3%), and 5/63 (7.9%) patients receiving flecainide 6 months, 3 months or standard of care, respectively [RD -2.9%; 95% CI -12.7% to 6.9%, and RD -1.6%; 95% CI -11.8% to 8.6%, respectively]. CONCLUSIONS: In the first 6 months following successful PFO closure, AA (≥30s) occurred in 28.5% of cases, mostly in the first month after the procedure. Flecainide did not prevent AA after PFO closure.

Ten-year trends in characteristics, management and outcomes of patients admitted with cardiogenic shock in the ACTION-SHOCK cohort.

BACKGROUND: The ACTION-SHOCK registry offers a decade-long perspective on patients admitted with cardiogenic shock (CS). AIMS: To assess trends in the management and outcomes of patients with CS over 10 years. METHODS: Trends in the characteristics, management and outcomes of patients with CS admitted into the cardiac intensive care unit of Pitié-Salpêtrière hospital from 2011 to 2020 were analysed. Short-term outcomes included in-hospital mortality, heart transplantation or ventricular assist device. Long-term outcomes were all-cause death or readmission for acute heart failure at 1 year. RESULTS: Over a 10-year period, data from 700 patients with CS (median [interquartile range] age 61 [50-72] years; 73% of men) were analysed. The proportion of CS related to acute myocardial infarction decreased (from 45% in 2011-2012 to 27% in 2019-2020) while the proportions related to chronic coronary syndrome (18% to 23%) and non-ischaemic cardiomyopathies (37 to 51%) increased (P<0.01). The use of rescue extracorporeal membrane oxygenation remained stable (19 to 14%) and intra-aortic balloon pump use decreased (22% to 7%) (P<0.01). In-hospital mortality remained stable (27 to 29%) as did the proportions of patients discharged after transplantation (17 to 14%) or with a durable ventricular assist device (2 to 4%). Among patients discharged alive, death or readmission for acute heart failure at 1 year remained high (37 to 47%). CONCLUSION: CS remained associated with a poor prognosis over the last decade. There are significant unmet needs in the management strategies of patients with CS.

Antithrombotic therapy for transcatheter structural heart intervention.

Percutaneous transcatheter structural heart interventions have considerably expanded within the last two decades, improving clinical outcomes and quality of life versus guideline-directed medical therapy for patients frequently ineligible for surgical treatment. Transcatheter structural heart interventions comprise valve implantation or repair and also occlusions of the patent foramen ovale, atrial septal defects and left atrial appendage. These procedures expose structural devices to arterial or venous blood flow with various rheological conditions leading to potential thrombotic complications and embolisation. Furthermore, these procedures may concern comorbid patients at high risk of both ischaemic and bleeding complications. This state-of-the-art review provides a description of the device-related thrombotic risk associated with these transcatheter structural heart interventions and of the current evidence-based guidelines regarding antithrombotic treatments. Gaps in evidence for each of the studied transcatheter interventions and the main ongoing trials are also summarised.

Determinants of adverse outcomes following patent foramen ovale closure in elderly patients.

BACKGROUND: Limited data are available on transcatheter patent foramen ovale (PFO) closure outcomes in the elderly. AIMS: Through this study, we aimed to determine the incidence and predictors of adverse events (recurrent cerebrovascular events [CVE] and atrial fibrillation [AF]) post-PFO closure in older patients with cryptogenic events. METHODS: This multicentre international study included patients over 60 years undergoing PFO closure for cryptogenic thromboembolic events. A dedicated database compiled baseline, procedural, and follow-up data. Competing risk and adjusted outcome predictor analyses were conducted. RESULTS: A total of 689 patients were included (median age 65 years, 41.2% female, mean Risk of Paradoxical Embolism [RoPE] score 4.5). The procedural success rate was 99.4%. After a median follow-up of 2 (interquartile range 1-5) years, 66 patients (9.6%) had died. CVE and stroke rates were 1.21 and 0.55 per 100 patient-years, respectively. Diabetes (hazard ratio [HR] 3.89, 95% confidence interval [CI]: 1.67-9.07; p=0.002) and atrial septal aneurysm (ASA; HR 5.25, 95% CI: 1.56-17.62; p=0.007) increased the CVE risk. New-onset AF occurred at a rate of 3.30 per 100 patient-years, with 51.3% within one month post-procedure. Older age (HR 1.05 per year, 95% CI: 1.00-1.09; p=0.023) and the absence of hypertension (HR 2.04, 95% CI: 1.19-3.57; p=0.010) were associated with an increased risk of AF. CONCLUSIONS: Older patients undergoing PFO closure had a relatively low rate of CVE and new-onset AF after a median follow-up of 2 years. The presence of diabetes, ASA, and a more advanced age determined an increased risk of adverse clinical events. These factors may be considered in the clinical decision-making process regarding PFO closure in this challenging population.

Changes in absolute coronary flow and microvascular resistance during exercise in patients with ANOCA.

BACKGROUND: Whether saline-induced hyperaemia captures exercise-induced coronary flow regulation remains unknown. AIMS: Through this study, we aimed to describe absolute coronary flow (Q) and microvascular resistance (Rµ) adaptation during exercise in participants with angina with non-obstructive coronary artery disease (ANOCA) and to explore the correlations between saline- and exercise-derived coronary flow reserve (CFR) and microvascular resistance reserve (MRR). METHODS: Rµ, Q, CFR and MRR were assessed in the left anterior descending artery using continuous thermodilution with saline infusion at 10 mL/min (rest), 20 mL/min (hyperaemia) and finally at a 10 mL/min infusion rate during stress testing with a dedicated supine cycling ergometer. An incremental workload of 30 watts every two minutes was applied. A saline-derived CFR (CFRsaline) cutoff <2.5 was used to identify coronary microvascular dysfunction (CMD). RESULTS: CFRsaline-defined CMD was observed in 53.3% of the participants (16/30). While cycling, these patients less of an ability to increase Q (7 [interquartile range [IQR] 30.5-103.0] vs 21 [IQR 5.8-45.0] mL/min/30 watts; p=0.01) due to a smaller decrease of Rµ (109 {IQR 32-286} vs 202 [IQR 102-379] Wood units [WU]/30 watts; p<0.01) as compared with the group with normal CFRsaline. In the overall population, CFRsaline and exercise-derived CFR (CFRexercise) were 2.70±0.90 and 2.85±1.54, respectively, with an agreement classification of 83.3%. A good correlation between saline and exercise techniques for both CFR (r=0.73; p<0.0001) and MRR (r=0.76; p<0.0001) was observed. Among participants with normal CFRsaline, 28.7% (4/14) had an impaired CFRexercise <2.5 at the peak of exercise due to a moderate and late decrease of Rµ. CONCLUSIONS: Saline-induced hyperaemia provided a valid surrogate for exercise physiology independently of the absolute level of CFR and MRR, although exercise provided more granularity to evaluate adaptation among participants with exercise-related CMD.

Beta-Blocker Interruption or Continuation after Myocardial Infarction.

BACKGROUND: The appropriate duration of treatment with beta-blocker drugs after a myocardial infarction is unknown. Data are needed on the safety and efficacy of the interruption of long-term beta-blocker treatment to reduce side effects and improve quality of life in patients with a history of uncomplicated myocardial infarction. METHODS: In a multicenter, open label, randomized, noninferiority trial conducted at 49 sites in France, we randomly assigned patients with a history of myocardial infarction, in a 1:1 ratio, to interruption or continuation of beta-blocker treatment. All the patients had a left ventricular ejection fraction of at least 40% while receiving long-term beta-blocker treatment and had no history of a cardiovascular event in the previous 6 months. The primary end point was a composite of death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for cardiovascular reasons at the longest follow-up (minimum, 1 year), according to an analysis of noninferiority (defined as a between-group difference of <3 percentage points for the upper boundary of the two-sided 95% confidence interval). The main secondary end point was the change in quality of life as measured by the European Quality of Life-5 Dimensions questionnaire. RESULTS: A total of 3698 patients underwent randomization: 1846 to the interruption group and 1852 to the continuation group. The median time between the last myocardial infarction and randomization was 2.9 years (interquartile range, 1.2 to 6.4), and the median follow-up was 3.0 years (interquartile range, 2.0 to 4.0). A primary-outcome event occurred in 432 of 1812 patients (23.8%) in the interruption group and in 384 of 1821 patients (21.1%) in the continuation group (risk difference, 2.8 percentage points; 95% confidence interval [CI], <0.1 to 5.5), for a hazard ratio of 1.16 (95% CI, 1.01 to 1.33; P = 0.44 for noninferiority). Beta-blocker interruption did not seem to improve the patients' quality of life. CONCLUSIONS: In patients with a history of myocardial infarction, interruption of long-term beta-blocker treatment was not found to be noninferior to a strategy of beta-blocker continuation. (Funded by the French Ministry of Health and ACTION Study Group; ABYSS ClinicalTrials.gov number, NCT03498066; EudraCT number, 2017-003903-23.).

Early and late hospital readmissions after percutaneous left atrial appendage closure.

INTRODUCTION AND OBJECTIVES: Percutaneous left atrial appendage closure (LAAC) has emerged as a nonpharmacological alternative for the prevention of thromboembolic events in patients with nonvalvular atrial fibrillation. However, there are few data on readmissions after LACC. The aim of this study was to determine the rate of early (≤ 30 days) and late (31-365 days) readmission after LAAC, and to assess the predictors and clinical impact of rehospitalization. METHODS: This multicenter study included 1419 consecutive patients who underwent LAAC. The median follow-up was 33 [17-55] months, and follow-up was complete in all but 54 (3.8%) patients. The primary endpoint was readmissions for any cause. Logistic regression and Cox regression analysis were performed to determine the predictors of readmission and its clinical impact. RESULTS: A total of 257 (18.1%) patients were readmitted within the first year after LAAC (3.2% early, 14.9% late). The most common causes of readmission were bleeding (24.5%) and heart failure (20.6%). A previous gastrointestinal bleeding event was associated with a higher risk of early readmission (OR, 2.65; 95%CI, 1.23-5.71). The factors associated with a higher risk of late readmission were a lower body mass index (HR, 0.96-95%CI, 0.93-0.99), diabetes (HR, 1.38-95%CI, 1.02-1.86), chronic kidney disease (HR, 1.60; 95%CI, 1.21-2.13), and previous heart failure (HR, 1.69; 95%CI, 1.26-2.27). Both early (HR, 2.12-95%CI, 1.22-3.70) and late (HR, 1.75; 95%CI, 1.41-2.17) readmissions were associated with a higher risk of 2-year mortality. CONCLUSIONS: Readmissions within the first year after LAAC were common, mainly related to bleeding and heart failure events, and associated with patients' comorbidity burden. Readmission after LAAC confered a higher risk of mortality during the first 2 years after the procedure.

Demystifying the Contemporary Role of 12-Month Dual Antiplatelet Therapy After Acute Coronary Syndrome.

For almost two decades, 12-month dual antiplatelet therapy (DAPT) in acute coronary syndrome (ACS) has been the only class I recommendation on DAPT in American and European guidelines, which has resulted in 12-month durations of DAPT therapy being the most frequently implemented in ACS patients undergoing percutaneous coronary intervention (PCI) across the globe. Twelve-month DAPT was initially grounded in the results of the CURE (Clopidogrel in Unstable Angina to Prevent Recurrent Events) trial, which, by design, studied DAPT versus no DAPT rather than the optimal DAPT duration. The average DAPT duration in this study was 9 months, not 12 months. Subsequent ACS studies, which were not designed to assess DAPT duration, rather its composition (aspirin with prasugrel or ticagrelor compared with clopidogrel) were further interpreted as supportive evidence for 12-month DAPT duration. In these studies, the median DAPT duration was 9 or 15 months for ticagrelor and prasugrel, respectively. Several subsequent studies questioned the 12-month regimen and suggested that DAPT duration should either be fewer than 12 months in patients at high bleeding risk or more than 12 months in patients at high ischemic risk who can safely tolerate the treatment. Bleeding, rather than ischemic risk assessment, has emerged as a treatment modifier for maximizing the net clinical benefit of DAPT, due to excessive bleeding and no clear benefit of prolonged treatment regimens in high bleeding risk patients. Multiple DAPT de-escalation treatment strategies, including switching from prasugrel or ticagrelor to clopidogrel, reducing the dose of prasugrel or ticagrelor, and shortening DAPT duration while maintaining monotherapy with ticagrelor, have been consistently shown to reduce bleeding without increasing fatal or nonfatal cardiovascular or cerebral ischemic risks compared with 12-month DAPT. However, 12-month DAPT remains the only class-I DAPT recommendation for patients with ACS despite the lack of prospectively established evidence, leading to unnecessary and potentially harmful overtreatment in many patients. It is time for clinical practice and guideline recommendations to be updated to reflect the totality of the evidence regarding the optimal DAPT duration in ACS.

Early Nonprocedural Bleeding After Left Atrial Appendage Occlusion.

BACKGROUND: Patients treated with left atrial appendage occlusion (LAAO) are at high bleeding risk. Intensive antithrombotic treatment is recommended after the procedure to prevent device-related thrombosis. OBJECTIVES: This study sought to evaluate the incidence, consequences, and predictors of early nonprocedural bleeding after LAAO. METHODS: This was a multicenter study including 1,649 patients undergoing LAAO in 9 centers. Early nonprocedural bleeding was defined as bleeding unrelated to the procedure occurring within 3 months after device implantation. The severity of bleeding was defined by the Valve Academic Research Consortium-2 classification. A sensitivity analysis was performed at 45 days. RESULTS: A total of 121 (7.3%) patients experienced early nonprocedural bleeding events, and 69 (57.0%) were classified as major bleeding (4.2% of patients). Independent predictors of early nonprocedural bleeding were dual antiplatelet therapy (DAPT) at discharge (adjusted HR [aHR]: 1.61; 95% CI: 1.12-2.33; P = 0.01), prior gastrointestinal bleeding (aHR: 2.15; 95% CI: 1.38-3.35; P < 0.001), and multiple locations of prior bleeding (aHR: 2.33; 95% CI: 1.34-4.05; P < 0.001). DAPT at discharge was predictive of both all and major nonprocedural bleeding at 3 months and 45 days. After a median follow-up of 2.3 years (Q1-Q3: 1.1-4.1 years), early nonprocedural bleeding was independently associated with an increased risk of all-cause death (aHR: 1.53; 95% CI: 1.15-2.06; P < 0.001). This heightened mortality risk was similar at 45 days. CONCLUSIONS: Early nonprocedural bleeding after LAAO occurred in ∼7% of patients within 3 months, with more than one-half being classified as major bleeding. Regardless of severity, early nonprocedural bleeding was associated with increased mortality. DAPT at discharge determined an increased risk of early nonprocedural bleeding after LAAO. These results emphasize the importance of bleeding risk for determining antithrombotic strategies after LAAO.

Impact of gender in patients with device-related thrombosis after left atrial appendage closure - A sub-analysis from the multicenter EUROC-DRT-registry.

BACKGROUND: Device-related thrombosis (DRT) is a common finding after left atrial appendage closure (LAAC) and is associated with worse outcomes. As women are underrepresented in clinical studies, further understanding of sex differences in DRT patients is warranted. METHODS AND RESULTS: This sub-analysis from the EUROC-DRT-registry compromises 176 patients with diagnosis of DRT after LAAC. Women, who accounted for 34.7% (61/176) of patients, were older (78.0 ± 6.7 vs. 74.9 ± 9.1 years, p = .06) with lower rates of comorbidities. While DRT was detected significantly later in women (173 ± 267 vs. 127 ± 192 days, p = .01), anticoagulation therapy was escalated similarly, mainly with initiation of novel oral anticoagulant (NOAC), vitamin K antagonist (VKA) or heparin. DRT resolution was achieved in 67.5% (27/40) of women and in 75.0% (54/72) of men (p = .40). In the remaining cases, an intensification/switch of anticoagulation was conducted in 50.% (9/18) of men and in 41.7% (5/12) of women. Final resolution was achieved in 72.5% (29/40) cases in women, and in 81.9% (59/72) cases in men (p = .24). Women were followed-up for a similar time as men (779 ± 520 vs. 908 ± 687 days, p = .51). Kaplan-Meier analysis revealed no difference in mortality rates in women (Hazard Ratio [HR]: 1.73, 95%-Confidence interval [95%-CI]: .68-4.37, p = .25) and no differences in stroke (HR: .83, 95%-CI: .30-2.32, p = .72) within 2 years after LAAC. CONCLUSION: Evaluation of risk factors and outcome revealed no differences between men and women, with DRT in women being diagnosed significantly later. Women should be monitored closely to assess for DRT formation/resolution. Treatment strategies appear to be equally effective.

Ticagrelor vs Clopidogrel in Clopidogrel-Naive Patients With Chronic Coronary Syndrome.

BACKGROUND: Whether ticagrelor may reduce periprocedural myocardial necrosis after elective percutaneous coronary intervention (PCI) in patients with and without chronic clopidogrel therapy is unclear. OBJECTIVES: This study sought to compare ticagrelor vs clopidogrel in patients with and without chronic clopidogrel therapy before undergoing elective PCI. METHODS: In this prespecified analysis of the ALPHEUS (Assessment of Loading With the P2Y12 Inhibitor Ticagrelor or Clopidogrel to Halt Ischemic Events in Patients Undergoing Elective Coronary Stenting) trial, patients were defined as clopidogrel(+) and clopidogrel(-) according to the presence and absence of clopidogrel treatment for ≥7 days before PCI, respectively. The primary endpoint was the composite of PCI-related myocardial infarction and major injury as defined by the third and fourth universal definition 48 hours after PCI. RESULTS: A total of 1,882 patients were included, 805 (42.7%) of whom were clopidogrel(+). These patients were older, had more comorbidities, and had more frequent features of complex PCI. The primary endpoint was less frequently present in clopidogrel(-) compared to clopidogrel(+) patients (32.8% vs 40.0%; OR: 0.73; 95% CI: 0.60-0.88), but no significant differences were reported for the risk of death, myocardial infarction, stroke, or transient ischemic attack at 48 hours or 30 days. Ticagrelor did not reduce periprocedural myocardial necrosis or the risk of adverse outcomes, and there was no significant interaction regarding the presence of chronic clopidogrel treatment. CONCLUSIONS: Clopidogrel-naive patients presented less periprocedural complications compared to clopidogrel(+) patients, a difference related to a lower risk profile and less complex PCI. The absence of clopidogrel at baseline did not affect the absence of a difference between ticagrelor and clopidogrel in terms of PCI-related complications supporting the use of clopidogrel as the standard of care in elective PCI in patients with or without chronic clopidogrel treatment.

Design and rationale of the CLEAR SYNERGY (OASIS 9) trial: A 2x2 factorial randomized controlled trial of colchicine versus placebo and spironolactone vs placebo in patients with myocardial infarction.

BACKGROUND: Patients experiencing myocardial infarction (MI) remain at high risk of future major adverse cardiovascular events (MACE). While low-dose colchicine and spironolactone have been shown to decrease post-MI MACE, more data are required to confirm their safety and efficacy in an unselected post-MI population. Therefore, we initiated the CLEAR SYNERGY (OASIS 9) trial to address these uncertainties. METHODS: The CLEAR SYNERGY trial is a 2 × 2 factorial randomized controlled trial of low-dose colchicine 0.5 mg daily versus placebo and spironolactone 25 mg daily versus placebo in 7,062 post-MI participants who were within 72 hours of the index percutaneous coronary intervention (PCI). We blinded participants, healthcare providers, research personnel, and outcome adjudicators to treatment allocation. The primary outcome for colchicine is the first occurrence of the composite of cardiovascular death, recurrent MI, stroke, or unplanned ischemia-driven revascularization. The coprimary outcomes for spironolactone are (1) the composite of the total numbers of cardiovascular death or new or worsening heart failure and (2) the first occurrence of the composite of cardiovascular death, new or worsening heart failure, recurrent MI or stroke. We finished recruitment with 7,062 participants from 104 centers in 14 countries on November 8, 2022, and plan to present the results in the fall of 2024. CONCLUSIONS: CLEAR SYNERGY is a large international randomized controlled trial that will inform the effects of low-dose colchicine and spironolactone in largely unselected post-MI patients who undergo PCI. (ClinicalTrials.gov Identifier: NCT03048825).

Three-Year Outcomes With Fractional Flow Reserve-Guided or Angiography-Guided Multivessel Percutaneous Coronary Intervention for Myocardial Infarction.

BACKGROUND: In patients with multivessel disease with successful primary percutaneous coronary intervention for ST-segment-elevation myocardial infarction, the FLOWER-MI trial (Flow Evaluation to Guide Revascularization in Multivessel ST-Elevation Myocardial Infarction) showed that a fractional flow reserve (FFR)-guided strategy was not superior to an angiography-guided strategy for treatment of noninfarct-related artery lesions regarding the 1-year risk of death from any cause, myocardial infarction, or unplanned hospitalization leading to urgent revascularization. The extension phase of the trial was planned using the same primary outcome to determine whether a difference in outcomes would be observed with a longer follow-up. METHODS: In this multicenter trial, we randomly assigned patients with ST-segment-elevation myocardial infarction and multivessel disease with successful percutaneous coronary intervention of the infarct-related artery to receive complete revascularization guided by either FFR (n=586) or angiography (n=577). RESULTS: After 3 years, a primary outcome event occurred in 52 of 498 patients (9.40%) in the FFR-guided group and in 44 of 502 patients (8.17%) in the angiography-guided group (hazard ratio, 1.19 [95% CI, 0.79-1.77]; P=0.4). Death occurred in 22 patients (4.00%) in the FFR-guided group and in 23 (4.32%) in the angiography-guided group (hazard ratio, 0.96 [95% CI, 0.53-1.71]); nonfatal myocardial infarction in 23 (4.13%) and 14 (2.56%), respectively (hazard ratio, 1.63 [95% CI, 0.84-3.16]); and unplanned hospitalization leading to urgent revascularization in 21 (3.83%) and 18 (3.36%; hazard ratio, 1.15 [95% CI, 0.61-2.16]), respectively. CONCLUSIONS: Although event rates in the trial were lower than expected, in patients with ST-segment-elevation myocardial infarction undergoing complete revascularization, an FFR-guided strategy did not have a significant benefit over an angiography-guided strategy with respect to the risk of death, myocardial infarction, or urgent revascularization up to 3 years. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02943954.

Prehospital crushed versus integral prasugrel loading dose in STEMI patients with a large myocardial area.

BACKGROUND: The effect of administering a crushed prasugrel loading dose is uncertain in patients presenting with a large myocardial infarction and ST-segment elevation myocardial infarction (STEMI). AIMS: The aim of this study was to investigate if patients with a large myocardial infarction may benefit from prehospital administration of a crushed prasugrel loading dose. METHODS: Patients from the CompareCrush trial with an available ambulance electrocardiography (ECG) were included in the study. An independent core laboratory confirmed a prehospital large myocardial area. We compared pre- and postprocedural angiographic markers, including Thrombolysis in Myocardial Infarction (TIMI) 3 flow in the infarct-related artery, high thrombus burden, and myocardial blush grade 3, in STEMI patients with and without a prehospital large myocardial area. RESULTS: Ambulance ECG was available for 532 patients, of whom 331 patients were identified with a prehospital large myocardial area at risk. Crushed prasugrel significantly improved postprocedural TIMI 3 flow rates in STEMI patients with a prehospital large myocardial area at risk (92% vs 79%, odds ratio [OR] 3.00, 95% confidence interval [CI]: 1.50-6.00) but not in STEMI patients without a prehospital large myocardial area at risk (91% vs 95%, OR 0.47, 95% CI: 0.14-1.57; pinteraction=0.009). CONCLUSIONS: Administration of crushed prasugrel may improve postprocedural TIMI 3 flow in STEMI patients with signs of a large myocardial area at risk on the ambulance ECG. The practice of crushing tablets of prasugrel loading dose might, therefore, represent a safe, fast and cost-effective strategy to improve myocardial reperfusion in this high-risk STEMI subgroup undergoing primary percutaneous coronary intervention.