Survival in Patients with Paramedic-Identified ST-Segment Elevation Myocardial Infarction

Informing Utstein-style reporting guidelines for prehospital thrombolysis: A scoping review

BACKGROUND

Rural Australians with acute myocardial infarction (AMI) face higher mortality rates due to limited access to specialised cardiac services. Paramedic-administered prehospital thrombolysis (PHT) has emerged as an alternative to primary percutaneous intervention (pPCI) for patients facing barriers or delays to cardiac care. There is variability in PHT practices among Australian ambulance services, lacking standardised definitions and outcome measures. The aim of this scoping review was to identify quality indicators and influencing factors associated with outcomes for patients receiving PHT.

METHODS

A systematic search of literature in SCOPUS and Academic Search Complete, CINAHL and Health Source: Nursing/Academic Edition databases via EBSCO (Health) was conducted following the Joanna Briggs Institute methodology. Peer-reviewed studies from the past decade were screened using search criteria relevant to prehospital thrombolysis and quality indicators. Data extraction was performed and themed using five domains from the Utstein-style template commonly known for standardised prehospital cardiac arrest reporting.

RESULTS

After removing duplicates, the search yielded 3596 articles with 28 empirical studies meeting inclusion criteria for the review. These were primarily retrospective cohort studies performed in Australia, Canada and the United States. The scoping review identified 24 clinical quality indicators and factors related to Emergency Medical Service (EMS) systems, AMI recognition and ambulance dispatch, patient variables, PHT processes and patient outcomes. These findings correlate to the Donabedian structure-process-outcome quality of care model and have utility to inform future PHT reporting guidelines for jurisdictional ambulance services.

CONCLUSIONS

Given the variability in prehospital practice across Australian ambulance services, standardised reporting on quality indicators for PHT is needed. The Utstein-style template used to report data on pre-hospital cardiac arrest, trauma and airway management could be used for quality improvement in PHT. This review presents 24 quality indicators representing system, recognition and response, patient, process, and outcomes related to PHT. These results could be used to inform a future Delphi study and Utstein-like reporting guideline for prehospital thrombolysis.

Prehospital Activation of the Cardiac Catheterization Laboratory in ST-Segment-Elevation Myocardial Infarction for Primary Percutaneous Coronary Intervention

Background Prehospital activation of the cardiac catheter laboratory is associated with significant improvements in ST-segment-elevation myocardial infarction (STEMI) performance measures. However, there are equivocal data, particularly within Australia, regarding its influence on mortality. We assessed the association of prehospital activation on performance measures and mortality in patients with STEMI treated with primary percutaneous coronary intervention from the Queensland Cardiac Outcomes Registry (QCOR). Methods and Results Consecutive ambulance-transported patients with STEMI treated with primary percutaneous coronary intervention were analyzed from January 1, 2017 to December 31, 2020 from the QCOR. The total and direct effects of prehospital activation on the primary outcomes (30-day and 1-year cardiovascular mortality) were estimated using logistic regression analyses. Secondary outcomes were STEMI performance measures. Among 2498 patients (mean age: 62.2±12.4 years; 79.2% male), 73% underwent prehospital activation. Median door-to-balloon time (34 minutes [26-46] versus 86 minutes [68-113]; P<0.001), first-electrocardiograph-to-balloon time (83.5 minutes [72-98] versus 109 minutes [81-139]; P<0.001), and proportion of patients meeting STEMI targets (door-to-balloon <60 minutes 90% versus 16%; P<0.001), electrocardiograph-to-balloon time <90 minutes (62% versus 33%; P<0.001) were significantly improved with prehospital activation. Prehospital activation was associated with significantly lower 30-day (1.6% versus 6.6%; P<0.001) and 1-year cardiovascular mortality (2.9% versus 9.5%; P<0.001). After adjustment, no prehospital activation was strongly associated with increased 30-day (odds ratio [OR], 3.6 [95% CI, 2.2-6.0], P<0.001) and 1-year cardiovascular mortality (OR, 3.0 [95% CI, 2.0-4.6]; P<0.001). Conclusions Prehospital activation of cardiac catheterization laboratory for primary percutaneous coronary intervention was associated with significantly shorter time to reperfusion, achievement of STEMI performance measures, and lower 30-day and 1-year cardiovascular mortality.

Survival after Resuscitated Out-of-Hospital Cardiac Arrest in Patients with Paramedic-Identified ST-Segment Elevation Myocardial Infarction Treated with Primary Percutaneous Coronary Intervention

Background: ST-segment elevation myocardial infarction (STEMI) is a common cause of out-of-hospital cardiac arrest (OHCA). For these patients, urgent angiography and revascularization is an important treatment goal. There is a lack of data on the prognosis of STEMI patients after OHCA, who are diagnosed and treated by paramedics prior to hospital transport for primary percutaneous coronary intervention (PCI).Methods: Included were adult STEMI patients identified and treated by paramedics in Queensland (Australia) from January 2016 to December 2019, transported to a hospital for primary PCI, and receiving primary PCI. Patients were grouped into those with resuscitated OHCA and those without OHCA. Clinically-important time intervals, angiographic and clinical profiles, and survival were described.Results: Patients with OHCA had longer time intervals from prehospital STEMI identification to reperfusion than those without OHCA (median 97 versus 87 mins, p = 0.001). The former had higher rates of cardiac arrhythmia history (50.5 versus 12.4%, p < 0.001), classified low left ventricular ejection fraction on admission (64.9 versus 50.1%, p = 0.006), and cardiogenic shock (5.2 versus 1.2%, p = 0.011) than the latter. A significantly higher proportion of patients with OHCA had multiple diseased vessels (16.9 versus 8.3%, p = 0.005). In-hospital, 30-day, and one-year mortality was low, being 4.1%, 4.1% and 5.2%, respectively, for STEMI patients with OHCA. The corresponding figures for those without OHCA were 1.6%, 1.8% and 3.3%, respectively.Conclusions: Survival in paramedic-identified STEMI patients treated with primary PCI following OHCA resuscitation was high. Rapid angiography and reperfusion are critical in these patients.