Pre-hospital thrombolysis for ST-segment elevation myocardial infarction in regional Australia: long-term follow up.

BACKGROUND: Delivering reperfusion therapy to patients with ST-segment elevation myocardial infarction (STEMI) in regional areas without access to tertiary cardiology care remains challenging. The systems of care in Hunter New England Health, New South Wales, Australia (area covered = 130 000 km2 ) to provide reperfusion to patients with STEMI involve a 12-lead electrocardiogram in the ambulance, discussion between cardiologist and paramedic, followed by pre-hospital thrombolysis (PHT) delivered in ambulance to appropriate patients >60 min from the cardiac catheterisation laboratories. Patients who can access the cardiac catheterisation laboratories within 60 min are treated with primary percutaneous coronary intervention (PCI). AIMS: We have previously reported excellent 12-month outcomes for patients receiving PHT and the aim of the current analysis is to look at the long term outcomes. METHODS: We assessed long-term all-cause mortality and major adverse cardiovascular events of STEMI patients undergoing PHT in our health district from August 2008 to August 2013 and compared with the primary PCI group. RESULTS: One hundred and fifty (mean age: 62 ± 13 years, males: 76%, n = 114) patients were administered PHT and 334 patients (mean age: 65 ± 13 years, males: 75%, n = 251) underwent primary PCI during the study period. During a median follow up of 6.2 years (interquartile range: 4.8-7.4 years) all-cause mortality was 16% and 19% in the PHT and primary PCI groups respectively (P = 0.4). CONCLUSION: Our real-world experience shows that PHT followed by early transfer to a primary PCI-capable centre is an effective reperfusion strategy, with comparable results to primary PCI, and mortality benefits are sustained to more than 6 years.

Pre-hospital thrombolysis in ST-segment elevation myocardial infarction: a regional Australian experience.

OBJECTIVE: The system of care in the Hunter New England Local Health District for patients with ST-segment elevation myocardial infarction (STEMI) foresees pre-hospital thrombolysis (PHT) administered by paramedics to patients more than 60 minutes from the cardiac catheterisation laboratory (CCL), and primary percutaneous coronary intervention (PCI) at the CCL for others. We assessed the safety and effectiveness of the pre-hospital diagnosis strategy, which allocates patients to PHT or primary PCI according to travel time to the CCL. DESIGN, SETTING AND PARTICIPANTS: Prospective, non-randomised, consecutive, single-centre case series of STEMI patients diagnosed on the basis of a pre-hospital electrocardiogram (ECG), from August 2008 to August 2013. All patients were treated at the tertiary referral hospital (John Hunter Hospital, Newcastle). MAIN OUTCOME MEASURES: The primary efficacy endpoint was all-cause mortality at 12 months; the primary safety endpoint was bleeding. RESULTS: STEMI was diagnosed in 484 patients on the basis of pre-hospital ECG; 150 were administered PHT and 334 underwent primary PCI. The median time from first medical contact (FMC) to PHT was 35 minutes (IQR, 28-43 min) and to balloon inflation 130 minutes (IQR, 100-150 min). In the PHT group, 37 patients (27%) needed rescue PCI (median time, 4 h; IQR, 3-5 h). The 12-month all-cause mortality rate was 7.0% (PHT, 6.7%; PCI, 7.2%). The incidence of major bleeding (TIMI criteria) in the PHT group was 1.3%; no patients in the primary PCI group experienced major bleeding. CONCLUSION: PHT can be delivered safely by paramedical staff in regional and rural Australia with good clinical outcomes.

Management of Acute Coronary Syndromes in Patients in Rural Australia: The MORACS Randomized Clinical Trial.

Importance: Treatment of ST-segment elevation myocardial infarction (STEMI) in rural settings involves thrombolysis followed by transfer to a percutaneous coronary intervention-capable hospital. The first step is accurate diagnosis via electrocardiography (ECG), but one-third of all STEMI incidents go unrecognized and hence untreated. Objective: To reduce missed diagnoses of STEMI. Design, Setting, and Participants: This cluster randomized clinical trial included 29 hospital emergency departments (EDs) in rural Australia with no emergency medicine specialists, which were randomized to usual care vs automatically triggered diagnostic support from the tertiary referral hospital (management of rural acute coronary syndromes [MORACS] intervention). Patients presenting with symptoms compatible with acute coronary syndromes (ACS) were eligible for inclusion. The study was conducted from December 2018 to April 2020. Data were analyzed in August 2021. Intervention: Triage of a patient with symptoms compatible with ACS triggered an automated notification to the tertiary hospital coronary care unit. The ECG and point-of-care troponin results were reviewed remotely and a phone call was made to the treating physician in the rural hospital to assist with diagnosis and initiation of treatment. Main Outcomes and Measures: The proportion of patients with missed STEMI diagnoses. Results: A total of 6249 patients were included in the study (mean [SD] age, 63.6 [12.2] years; 48% female). Of 7474 ED presentations with suspected ACS, STEMI accounted for 77 (2.0%) in usual care hospitals and 46 (1.3%) in MORACS hospitals. Missed diagnosis of STEMI occurred in 27 of 77 presentations (35%) in usual care hospitals and 0 of 46 (0%) in MORACS hospitals (P < .001). Of eligible patients, 48 of 75 (64%) in the usual care group and 36 of 36 (100%) in the MORACS group received primary reperfusion (P < .001). In the usual care group, 12-month mortality was 10.3% (n = 8) vs 6.5% (n = 3) in the MORACS group (relative risk, 0.64; 95% CI, 0.18-2.23). Patients with missed STEMI diagnoses had a mortality of 25.9% (n = 7) compared with 2.0% (n = 1) for those with accurately diagnosed STEMI (relative risk, 13.2; 95% CI, 1.71-102.00; P = .001). Overall, there were 6 patients who did not have STEMI as a final diagnosis; 5 had takotsubo cardiomyopathy and 1 had pericarditis. There was no difference between groups in the rate of alternative final diagnosis. Conclusion and Relevance: The findings indicate that MORACS diagnostic support service reduced the proportion of missed STEMI and improved the rates of primary reperfusion therapy. Accurate diagnosis of STEMI was associated with lower mortality. Trial Registration: anzctr.org.au Identifier: ACTRN12619000533190.

Not All STEMI Patients Receive Timely Reperfusion: Considerations for Rural Emergency Departments.

Early reperfusion for ST-elevation myocardial infarction (STEMI) is well known to improve patient outcomes. A review of patient records in one rural health service in New South Wales, Australia, suggested that not all STEMI patients were receiving timely reperfusion. Consequently, the aim of this study was to further investigate factors influencing clinical decision making by primary care providers in relation to rural STEMI patients. This cross-sectional observational study was in two phases, a retrospective audit of patient records and a survey of rural general practitioners (GPs). In the first phase, patients with STEMI who were referred from small rural hospitals to a regional hospital emergency department (ED) were identified through the local health district database. In phase two, information from the database informed questions for a survey distributed to the GP visiting medical officers (VMOs) at small rural hospitals in the region. The survey was designed to ascertain factors that may contribute to delays in the care of STEMI patients. Of the STEMI patients identified (n = 139), 15% (21) who were eligible for medical reperfusion were not administered thrombolysis within 4 hours of triage. Auditing of this group's records found that ECGs were inaccurately interpreted for 76% of the missed STEMI patients. In the survey, about 55% of the GP respondents said they "very much agree" with the statement that they felt competent in STEMI management. Only 64% of the GP VMOs agreed they felt competent in diagnosis and management of a failed thrombolysis and not all respondents were aware of the relevant clinical guideline. Patients with missed STEMI are at higher risk of morbidity and mortality and increased length of stay, adding burden to the patient, carer and health service. Without addressing gaps in service provision and better adherence to clinical guidelines, unacceptable delays in STEMI management in rural health services are likely to continue.

Nursing-led ultrasound to aid in trans-radial access in cardiac catheterisation: a feasibility study.

BACKGROUND: Trans-radial access is increasingly common for cardiac catheterisation. Benefits include reduced bleeding complications, length of hospital stay and costs. AIMS: To determine the feasibility of implementing a nurse-led ultrasound programme to measure radial artery diameter before and after cardiac catheterisation; to determine radial artery occlusion (RAO) rates, risk factors for RAO and predictors of radial artery (RA) diameter. METHOD: A prospective observational cohort study design for 100 consecutive patients undergoing cardiac catheterisation, using RA access. Pre- and post-procedural RA diameter were measured using ultrasound, by specialist nurses trained to do so. Logistic regression analyses were performed to determine risk factors for RAO and predictors of RA diameter with results reported as odds ratios (OR) and 95% confidence intervals (CI). RESULTS: There were no adverse events, supporting the feasibility of nurse led ultrasound programmes. A 4% (n = 4) rate of occlusion was observed. Haemostasis device application time of greater than 190 min was a predictor of RAO (OR 3.12, 95% CI 0.31-31). Male gender and height were predictors for a RA diameter of >2.2 mm. CONCLUSIONS: Nurses can lead the assessment of RA occlusion using ultrasound to enhance planning and care, including monitoring compression times to reduce RAO.

Missed Acute Myocardial Infarction (MAMI) in a rural and regional setting.

BACKGROUND: Delay in treatment and/or failure to provide reperfusion in ST-segment elevation myocardial infarction (STEMI) impacts on morbidity and mortality. This occurs more often outside metropolitan areas yet the reasons for this are unclear. This study aimed to describe factors associated with missed diagnosis of acute myocardial infarction (MAMI) in a rural and regional setting. METHODS: Using a retrospective cohort design, patients who presented with STEMI and failed to receive reperfusion therapy within four hours were identified as MAMI. Univariate analyses were undertaken to identify differences in clinical characteristics between the treated STEMI group and the MAMI group. Mortality, 30-day readmission rates and length of hospital stay are reported. RESULTS: Of 100 patients identified as MAMI (70 male, 30 female), 24 died in hospital. Demographics and time from symptom onset were similar in the treated STEMI and MAMI groups. Of the MAMI patients who died, rural hospitals recorded the highest inpatient mortality (69.6% p = 0.008). MAMI patients compared to treated STEMI patients had higher 30 day readmission (31.6% vs 3.3%, p = 0.001) and longer length of stay (5.5 vs 4.3 days p = 0.029). Inaccurate identification of STEMI on electrocardiogram (72%) and diagnostic uncertainty (65%) were associated with MAMI. The Glasgow algorithm to identify STEMI was utilised on 57% of occasions, with 93% accuracy. CONCLUSION: Mortality following MAMI is high particularly in smaller rural hospitals. MAMI results in increased length of stay and readmission rate. Electrocardiogram interpretation and diagnostic accuracy require improvement to determine if this improves patient outcomes.

Clozapine and incidence of myocarditis and sudden death - Long term Australian experience.

BACKGROUND: Clozapine is the cornerstone of therapy for refractory schizophrenia; however, the potential for cardiotoxicity is an important limitation in its use. In the current analysis we sought to evaluate the long term cardiac outcomes of clozapine therapy. METHODS: All-cause mortality, incidence of sudden death and time to myocarditis were assessed in a cohort of patients maintained on clozapine between January 2009 and December 2015. All patients had regular electrocardiograms, complete blood count, clozapine levels and echocardiography as part of a formal protocol. RESULTS: A total of 503 patients with treatment-resistant schizophrenia were maintained on clozapine during the study period of which 93 patients (18%) discontinued therapy with 29 (6%) deaths. The incidence of sudden death and myocarditis were 2% (n=10) and 3% (n=14) respectively. Amongst patients with sudden death, 7 out of 10 (70%) were documented to have used illicit drugs prior to death, with a tendency to weight gain also noted. The mean time to myocarditis post clozapine commencement was 15±7days. The reduction in left ventricular ejection fraction in those with myocarditis was 11±2%. CONCLUSION: Myocarditis and sudden cardiac death are uncommon but clinically important complications in a cohort of patients followed while maintained on clozapine undergoing regular cardiac assessment. Further studies are required to document the role of preventive measures for left ventricular dysfunction and sudden cardiac death in this population.

Pros, cons, and organization of prehospital thrombolysis.

BACKGROUND: Early initiation of reperfusion therapy in ST-segment elevation myocardial infarction improves outcome. Prehospital thrombolysis (PHT) is 1 strategy to deliver earlier reperfusion. OBJECTIVE: The goal of this study was to discuss the pros and cons of PHT and to describe the implementation of a program of PHT in the Hunter Region of Australia. METHODS: Recent literature on PHT was reviewed to present a critical assessment of the evidence to support PHT. Different models of PHT are presented including the experience of the introduction of the Hunter program. RESULTS: Meta-analyses of clinical trials and registries have shown that PHT significantly decreases the time to thrombolysis, with reduction in the incidence of cardiogenic shock and a trend to a mortality benefit. The STREAM study reinforces current policy, which favors primary percutaneous coronary intervention (PCI) over thrombolysis, providing that PCI can be performed within an appropriate time interval; emphasizes that timely thrombolysis linked to an early invasive strategy provides an equivalent outcome when timely primary PCI is not possible; and supports other published experience that early-rescue PCI can be performed safely after administration of PHT. Although PHT can be implemented by trained paramedics working with on-board physicians, the Hunter Region has successfully used paramedics and ECG telemetry in consultation with hospital-based physicians. When the time to open the artery is ≤90 minutes, primary PCI is preferred. When the time to open the artery is >90 minutes, PHT with immediate transport postthrombolysis to a PCI-capable hospital is feasible and effective. CONCLUSIONS: PHT delivered by trained paramedics with telemetery backup to assist ECG interpretation is feasible and delivers the prospect of early reperfusion.