Ann Arbor, MI - The vast majority of the adult population in the US lives near enough to a PCI hospital that it may be feasible to set up a system in which prehospital triage protocols are used to send STEMI patients directly to these centers, a new study suggests [1].

The study, published in the March 7, 2006 issue of Circulation, was conducted by a team led by Dr Brahmajee Nallamothu (Ann Arbor VA Medical Center, MI) and Dr Harlan Krumholz (Yale University School of Medicine, New Haven, CT).

They explain that primary PCI is more effective than thrombolysis as reperfusion therapy for patients with STEMI, but it must be performed rapidly. Therefore, the idea of prehospital ambulance triage of patients with STEMI to PCI hospitals has been suggested. This would be similar to the system already in place for trauma, where patients with serious injuries are sent to specialized trauma centers. Nallamothu et al note that the success of such a system for STEMI patients depends on how patients are geographically distributed around PCI and non-PCI hospitals and whether timely access can be achieved. They therefore conducted a study to establish driving times and distances to the closest PCI hospital for the US adult population.

They obtained PCI status of hospitals from the American Hospital Association annual survey and established the location of the population from the 2000 US census.

They found that 79% of the adult population lived within 60 minutes of a PCI hospital. This included time for emergency-medical-system activation, ambulance arrival, early treatment and stabilization, and driving times. Among those with hospitals without PCI as their closest facility, 74% lived in areas where the additional time required to arrive at a PCI hospital was less than 30 minutes. The median time to the closest PCI hospital was 11.4 minutes, and the median distance to a PCI hospital was eight miles, but obviously the estimates varied across regions and among urban, suburban, and rural areas.

In an interview with heartwire, Nallamothu said these results suggest that there are no geographical restrictions to a prehospital triage strategy for the majority of STEMI patients. But he added that geographical location was only one part of the whole equation. "This is the first step, but there are many other factors that need to be taken into account," he commented. He explained that prehospital triage for STEMI patients would be more difficult than for trauma patients, as it is less obvious which patients are having an MI. "For trauma patients, it is usually obvious which patients are seriously injured and need to be sent to the trauma center. For patients with chest pain, an ECG needs to be done before a decision can be made, so getting ECG machines in ambulances and training the paramedics is the major issue here," he said.

Nallamothu explained that the difficulties arose because the emergency medical system in the US varies widely and therefore making changes is not easy. "The ambulance service is not a nationalized system. It is very localized and can be run by the fire brigade, the hospital, or even volunteers. Getting ECGs inside all ambulances would be hard to achieve given all the different ambulance services in place."

Another issue to contend with is economics and the competitiveness of the American hospital system. Nallamothu pointed out that the non-PCI hospitals would not want to lose their STEMI patients, as this would mean losing payments. "STEMI patients are fairly lucrative in that there is good reimbursement for their treatment. Few hospitals would want to give these patients up, and so it could be difficult to get hospitals to cooperate with each other," he said.

"And then we have to establish if it is actually worth it in the end—does the 1% to 2% benefit in absolute mortality associated with primary PCI justify completely changing the system to achieve this?" Nallamothu asked. "We have shown that geographically it would be possible to implement a prehospital triage system for STEMI patients, who could then be directed straight to PCI centers, But now we have to figure out if this is worth doing," he added.

In an accompanying editorial, Dr Alice Jacobs (Boston Medical Center, MA) points out several other barriers to the implementation of regional STEMI centers [2]. These include the fact that patients must promptly contact the medical system when experiencing chest pain and that public-education campaigns to encourage this have not yet demonstrated an improvement in rapid access to care. And she notes that many patients are still treated with thrombolysis at PCI hospitals and that systems need to be improved at the PCI centers to ensure fewer delays once at the hospital.

Jacobs says that as the evidence strongly favors primary PCI as the preferred reperfusion strategy for the majority of STEMI patients, "we must continue to explore the safety, efficacy, and feasibility of regional systems of care." She adds: "It will be necessary to bring together the stakeholders (patients, physicians, healthcare providers, community hospitals, tertiary centers, emergency medical systems, and payers) in the care of STEMI patients to understand the gaps between the current and ideal systems of care, and the American Heart Association is leading an initiative to do so."

She concludes: "It will be necessary to balance financial disincentives for hospitals without PCI capability with incentives to treat and transfer STEMI patients and with the savings to the global healthcare system, not only in dollars but in the number of lives saved. Only then will we be able to translate the benefits of primary PCI into clinical practice."