Elsevier

Annals of Emergency Medicine

Volume 58, Issue 3, September 2011, Pages 257-266
Annals of Emergency Medicine

Cardiology/original research
Transfer Travel Times for Primary Percutaneous Coronary Intervention From Low-Volume and Non–Percutaneous Coronary Intervention–Capable Hospitals to High-Volume Centers in Florida

https://doi.org/10.1016/j.annemergmed.2011.02.022Get rights and content

Study objective

Current guidelines recommend that ST-elevation myocardial infarction (STEMI) patients receive percutaneous coronary intervention less than or equal to 90 minutes from first medical contact, preferably at high-volume percutaneous coronary intervention centers (≥400 percutaneous coronary interventions annually). Because many patients present to low-volume or non–percutaneous coronary intervention–capable STEMI referral hospitals, timely percutaneous coronary intervention treatment requires effective transfer systems, which include interfacility transport times of less than 30 minutes. We investigate the geographic feasibility of achieving timely interfacility transport from STEMI referral hospitals to percutaneous coronary intervention hospitals in Florida.

Methods

Using 2006 Florida hospital discharge data, we calculated driving times between STEMI referral hospitals and the nearest medium-/high-volume percutaneous coronary intervention centers. We plotted transfer travel time cumulative proportion survival curves for hospitals and patients to assess the feasibility of transfer within 30 minutes to higher-volume facilities. Differences by geographic location (rural versus urban) and patient race/ethnicity were examined.

Results

In 2006, 77% of STEMI referral hospitals had transfer travel times within 30 minutes; 90th percentile for interhospital driving time was 56 minutes. For patients at STEMI referral hospitals, 85.6% were at facilities within a 30-minute drive of a high-/medium-volume percutaneous coronary intervention center; 90th percentile was 31 minutes. We found marked rural/urban disparities, with longer average driving times for patients in rural and small metropolitan counties. Significant racial/ethnic disparities in transfer travel times were not observed, although 90th percentile driving times were highest for blacks.

Conclusion

Driving times do not pose a major geographic barrier to transfer of STEMI patients in Florida. A majority of STEMI patients could be transferred from STEMI referral hospitals to high-volume percutaneous coronary intervention centers within 30 minutes.

Introduction

Primary percutaneous coronary intervention is the preferred treatment for acute ST-elevation myocardial infarction (STEMI) when performed within 90 minutes of first medical contact with the patient.1, 2, 3 American College of Cardiology (ACC)/American Heart Association (AHA) practice guidelines for percutaneous coronary intervention specify that treatment should be given by experienced operators at high-volume centers, ideally designated as those hospitals that perform greater than or equal to 400 percutaneous coronary interventions annually.2 However, only about 20% of acute care hospitals in the United States have cardiac catheterization laboratories, and only a subset of those hospitals are high-volume centers that offer primary percutaneous coronary intervention on a continuous, emergency basis.4 Consequently, regionalization protocols have been implemented in several areas, with the key element of routine bypass of non–percutaneous coronary intervention and low-volume centers by emergency medical services (EMS) and direct transport of patients with known or suspected STEMI to high-volume percutaneous coronary intervention centers.5, 6, 7, 8

However, even successful regionalization protocols cannot entirely eliminate the need for patients to be transported to a non–percutaneous coronary intervention or low-volume center, nor can they control for patient self-transport to the hospital. Many individuals with symptoms and signs of an acute coronary event do not call 911 (even when paramedic services are readily available) and instead choose to drive themselves or be driven to a hospital of choice.9 Antman et al1 addressed these situations in the AHA's 2007 focused guideline update. For patients transported by EMS or those who self-transport to a non–percutaneous coronary intervention center, interhospital transfer to a percutaneous coronary intervention center could be considered if percutaneous coronary intervention can be performed within 90 minutes of first medical contact. Similarly, an AHA initiative on STEMI systems of care stated that in an ideal system, patients who self-transport to a non–percutaneous coronary intervention–capable hospital would receive a diagnosis in the emergency department (ED) within 30 minutes of check-in, be urgently transported to a percutaneous coronary intervention hospital with a travel time of less than 30 minutes, and then receive percutaneous coronary intervention within 30 minutes of arrival at the high-volume center.10 The most recent AHA/ACC guidelines reiterate that interfacility transport of STEMI patients should occur in less than 30 minutes.11 Transfer travel time consists primarily of driving time but is also affected by ambulance availability and patient preparation for transport.

European clinical trials report that routine transfer of STEMI patients to percutaneous coronary intervention centers is safe and feasible and can be accomplished rapidly within recommended time-to-reperfusion guidelines.12, 13, 14, 15, 16 Nallamothu et al17 found that nearly 80% of the US population lives within a 60-minute drive of a percutaneous coronary intervention–capable hospital. Although 58% of the US population lives closer to a non–percutaneous coronary intervention hospital, in 74% of cases these individuals could be transferred to a percutaneous coronary intervention–capable facility in 30 minutes or less.17 Another study determined through geographic information systems analysis that 70% of the population of Alberta could be transferred by ground within 90 minutes to one of the province's 3 percutaneous coronary intervention–capable hospitals, despite substantial travel distances and geographic barriers.18 However, skepticism exists about whether the success of transfer systems in Europe can be duplicated in North America, and there is some question about whether regional systems for percutaneous coronary intervention should be adopted at all.19

Benefits to transferring patients for percutaneous coronary intervention over fibrinolysis have been demonstrated when percutaneous coronary intervention is performed within 90 minutes of first medical contact.20, 21 In a meta-analysis of randomized controlled trials, De Luca et al21 determined that patients transferred for percutaneous coronary intervention had significantly lower mortality, reinfarction, and stroke at 30-day follow-up. However, the benefits of percutaneous coronary intervention dissipate when the procedure is not performed within 90 minutes of first medical contact.22

Some non–percutaneous coronary intervention–capable hospitals use a facilitated percutaneous coronary intervention strategy, administering fibrinolysis and then transferring patients to a percutaneous coronary intervention–capable hospital for percutaneous coronary intervention. Although some studies suggest this strategy may offer benefits in situations in which door-to-balloon times are greater than 90 minutes and less than 150 minutes,23 others have not found any advantage to using facilitated percutaneous coronary intervention over primary percutaneous coronary intervention.24

Chakrabati et al,25 in an analysis of the National Cardiovascular Data Registry, determined the median door-to-balloon time for STEMI patients transferred for percutaneous coronary intervention was 152 minutes, with only 8.6% of percutaneous coronary interventions performed within 90 minutes.25 Achieving door-to-balloon times of less than 90 minutes hinges on transfer driving times of less than 30 minutes. This study shows that such a benchmark is achievable for the majority of patients within Florida, which has important implications for the design of regional STEMI care networks.

In this study, we examine the travel time feasibility of routine transfers from low-volume and non–percutaneous coronary intervention hospitals to high-volume facilities, using empirical data from Florida for 2006. To our knowledge, our study is the first to use actual STEMI patient hospital admission patterns to evaluate the feasibility of routine, emergency transfer to STEMI receiving hospitals in the United States.

Section snippets

Study Design

The study uses a retrospective cohort design with a source population of Florida STEMI patients treated in 2006 at hospitals that do not meet the current AHA/ACC guidelines for percutaneous coronary intervention volume. This is not a study of patient outcomes, but rather a hospital-level study to determine the feasibility of transfers, using actual patient data. We assess potential driving times that would have been required to transfer these patients to hospitals that meet or exceed the

Results

We excluded certain hospital types from our analyses: children's hospitals, psychiatric and behavioral health facilities, and long-term care facilities. Data were not available for Veterans Administration facilities, which may infrequently accept STEMI patients through their EDs. After exclusions, there were 191 short-term acute care hospitals with EDs in Florida in 2006. These hospitals served a state of 58,560 square miles, with a population of more than 17 million residents, plus a small

Limitations

This study describes the feasibility of interhospital transfers of STEMI patients according to usual average driving times. It does not account for the effect of logistic, administrative, and systems factors (eg, ambulance response times) on out-of-hospital and interhospital times or random events (eg, inclement weather, traffic jams, accidents) that could affect actual transfer times in specific cases. The driving times we calculated are based on regular passenger vehicles under normal traffic

Discussion

In 2006, the majority of Florida STEMI patients who presented to STEMI referral hospitals could have been transferred to a high- or medium-volume facility within the AHA recommended period of 30 minutes. Moreover, 77% of STEMI referral hospitals and 85.6% of all the STEMI patients served by STEMI referral hospitals were within a 30-minute drive of a high- or medium-volume percutaneous coronary intervention hospital. These numbers are consistent with the national estimates calculated by

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    Supervising editor: Judd E. Hollander, MD

    Author contributions: EBP conceived of the study idea. EBP, GA, JPT, and MMC performed statistical analyses. EBP and CJF drafted the article. EBP, CJF, and JAS and revised the article. GA, JPT, and MMC assisted with data compilation. GA assisted with preparation of figures. EBP takes responsibility for the paper as a whole.

    Funding and support: By Annals policy, all authors are required to disclose any and all commercial, financial, and other relationships in any way related to the subject of this article as per ICMJE conflict of interest guidelines (see www.icmje.org). This study was funded by Grant-in-Aid 0855374E from the American Heart Association, Greater Southeast Affiliate.

    Earn CME Credit: Continuing Medical Education is available for this article at: www.ACEP-EMedHome.com.

    Publication date: Available online April 19, 2011.

    Please see page 258 for the Editor's Capsule Summary of this article.

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