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Telemedicine to improve outcomes for patients with acute myocardial infarction
  1. Nichole Bosson1,2
  1. 1 Los Angeles County EMS Agency, Santa Fe Springs, California, USA
  2. 2 Los Angeles County Harbor-UCLA Medical Center, Torrance, California, USA
  1. Correspondence to Dr Nichole Bosson, Los Angeles County EMS Agency, Santa Fe Springs, CA 90670, USA; nbosson{at}dhs.lacounty.gov

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The use of telemedicine, allowing for the transfer of clinical information and remote delivery of healthcare services using telecommunications technology, is rapidly expanding. Telemedicine capabilities are increasingly available between providers at healthcare centres, and between hospital and emergency medical services (EMS), extending the physician’s reach into the prehospital realm without leaving the hospital. The use of telemedicine to transfer data from the field to the hospital and/or to facilitate communication between the physician and EMS providers is typically focused on reducing the time to treatment, with the ultimate goal of improving patient outcomes. Time-sensitive conditions, such as acute myocardial infarction (AMI) and stroke, have been a primary focus given the perceived potential for benefit.

In their Heart paper, Marcolino et al report the results of a systematic review and meta-analysis evaluating the impact of telemedicine interventions on door-to-balloon (D2B) time, in-hospital mortality, and 30-day and long-term mortality in patients with AMI1. The authors found a relative risk of 0.63 (95% CI 0.55 to 0.72), resulting in a number needed to treat of 29 for the primary outcome of in-hospital mortality. This result was based on moderate-quality evidence from 17 observational studies, in 10 of which patients were treated with percutaneous coronary intervention (PCI) and the other 7 with thrombolysis. They report a similar reduction in D2B times (process outcome) and long-term mortality (patient-centred outcome). However, the quality of evidence was very poor, with large heterogeneity observed in the effect on D2B time and very few studies evaluating long-term outcomes.

In the meta-analysis by Marcolino et al, ECG transmission was the main intervention, with or without teleconsultation, in all of the 35 studies included. Further, 31 of the 35 studies focused on transmission of the prehospital ECG to the hospital. Therefore, the results may be viewed as an evaluation of the effect of ECG transmission on outcomes from AMI, rather than a broader analysis of telemedicine strategies. ECG transmission has significant challenges. Despite the feasibility demonstrated in small pilot studies, system-wide success rates for ECG transmission have been reported as low as 20%–28%.2 3 In addition to the difficulty of maintaining consistent data transmission, barriers include lack of infrastructure, training and expense.4 Without clear evidence of benefit, many EMS systems have been hesitant to develop this process. An alternative to ECG transmission is paramedic interpretation of the ECG and direct activation of the catheterisation laboratory. Studies evaluating the sensitivity and specificity of prehospital provider interpretation of ECGs vary with a sensitivity of 71%–97% and a specificity of 91%–100%.5 Prenotification of the catheterisation laboratory alone, without relying on ECG transmission, has been shown to significantly reduce time to treatment for patients with AMI.6 It can be difficult to distinguish the effects of prenotification from the effects of ECG transmission and teleconsultation. A prior meta-analysis demonstrated a reduction in short-term mortality with prehospital ECG acquisition and advanced hospital notification for patients with AMI, including studies both with and without ECG transmission.7 However, in the meta-analysis by Marcolino et al, some studies included advanced notification as part of standard care in the control group, suggesting that telemedicine strategies may potentially have an additional additive effect.

Both advanced notification and ECG transmission are intended to reduce time to treatment for patients with AMI, based on the concept that shorter ischaemic time results in greater myocardial salvage, and ultimately better clinical outcomes. There has been a significant focus on reduction in D2B times in recent years, with considerable success, but this has not consistently resulted in the expected decrease in mortality.8 Some have questioned whether further reduction in D2B times will reduce mortality, given D2B time is just one interval in the total ischaemic time.8 Appropriately, in cardiac systems of care, there has been a shift in focus to first-medical-contact-to-balloon time, which also accounts for the prehospital phase of care. Still, the majority of ischaemic time results from delays in symptom onset to presentation, a difficult interval to target. It is possible that the outcome of mortality is not granular enough to detect the benefits of the incremental reduction in time to treatment that results from the addition of telemedicine to well-established systems of care. Patient-centred outcomes that include a measurement or assessment of quality of life may better demonstrate these small gains.

There are additional system considerations that also make telemedicine appealing for cardiac systems of care. These are more challenging to measure in regard to individual patient outcomes. Triage of patients in the prehospital setting has become increasingly complicated, with paramedics expected to further and further dissect the likely diagnosis to transport each patient to the specialty centre best suited to their needs. Telemedicine assists in this triage process, ensuring patients are transported to the correct location. In the case of a patient with AMI, paramedics must determine which patients will benefit from direct transport to a PCI-capable centre for ST-elevation myocardial infarction (STEMI) ,or in some systems which patients require thrombolysis. Transport to the specialty centre, bypassing local hospitals, takes that response unit out of their service area. This forces coverage from other nearby units and results in potential response time delays for other emergencies that occur during that time. In addition, false positive activations of the catheterisation team are common.9 10 Telemedicine can reduce the excessive use of system resources by preventing these unnecessary transports, increasing the specificity of STEMI activations and keeping paramedics within their service areas. Finally, telemedicine may prevent missed STEMI, the consequences of which are long delays in care for those patients who require secondary transfer to the PCI-capable hospital.11

Among the studies included by Marcolino et al, 14 also included a component of teleconsultation. The addition of teleconsultation to data transmission from the field offers promising advantages by allowing the physician to engage in the prehospital phase of care, potentially evaluating the patient remotely and bringing traditionally in-hospital management into the field. This is particularly transformative in Anglo-American EMS systems, which typically do not deploy physicians to the field. A key example of the successful expansion of teleconsultation is in patients with acute ischaemic stroke. Many hospital systems have implemented telemedicine to bring neurology specialists to the bedside at hospitals without onsite consultants. Further, telemedicine has been implemented in EMS systems with the deployment of mobile stroke units bringing neuroimaging and thrombolysis into the field, resulting in a significant reduction in time to treatment.12 These systems, which allow direct video communication between the physician and the patient, may benefit patients with AMI as well (figure 1). In patients with acute cardiovascular emergencies, the advantage of seeing not just the ECG but also the patient cannot be understated.

Figure 1

University of California, Los Angeles mobile stroke unit. Photo courtesy of Dr May Nour.

Marcolino et al included 35 studies conducted in 14 different countries on 5 continents. Clearly, telemedicine for AMI is expanding across the globe, but it is still in its infancy. The majority of the studies were limited to transmission of the ECG, with some including teleconsultation which occurred via telephone communication between the physician and the prehospital providers or the patient. In one study involving field transmission, images of the patient were also transmitted.13 The single study involving video communication connected a private hospital network.14

Telemedicine holds promise for the management in the acute phase of AMI and for postdischarge care. Telemedicine can allow for remote follow-up and close monitoring of patients, ensuring medication compliance, and detecting early signs of decompensation before it results in additional complications and hospital readmission. Transmission of data from the patient’s home and the ability of the physician to evaluate the patient remotely can expand the possibilities for home-based care and improve patient quality of life. This is especially valuable in rural communities, where physician specialists are lacking and patients have long travel times to seek care. There are incredible opportunities for the use of telemedicine to improve patient outcomes that have yet to be realised. Future studies should expand on these promising innovations in care and attempt to further quantify the benefit to patients beyond process outcomes and short-term mortality.

References

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Footnotes

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Commissioned; internally peer reviewed.

  • Patient consent for publication Not required.

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