ABSTRACT: Background. Recent data from large national registries show that Methods
Design and protocol. The UVM Transfer STEMI program is a pilot program established in February 2007 to offer primary PCI as the default reperfusion strategy for patients presenting with STEMI to a referral hospital 27 miles north of UVM. The STEMI referral hospital is a 70-bed hospital with 30,000 annual emergency room visits. Fletcher Allen Health Care is a 615-bed university hospital affiliated with UVM that performs a high volume of PCI by 8 interventional cardiologists. The STEMI protocol was designed to facilitate initial triage and care at the referring hospital and immediate transfer of all suspected STEMI patients for primary PCI to UVM. The protocol required full approval of the local emergency medical services and emergency department (ED) staff.
All patients from February 2007 to September 2008 presenting within 12 hours of onset of chest pain and with electrocardiographic (ECG) ST elevation ≥ 1 mm in ≥ 2 contiguous leads or a presumed new left bundle branch block at the STEMI referring hospital were considered eligible for the program, including patients in cardiogenic shock. We modeled our protocol to incorporate strategies that have been shown to reduce D2B times.13–16 These strategies included having emergency medicine physicians activate the catheterization laboratory via a single call to a central page operator to activate the laboratory, expecting staff to arrive in the catheterization laboratory within 20 minutes after being paged, and having staff in the ED and the catheterization laboratory use real-time data feedback from the referral hospital, UVM ED staff and EMS. Pre-hospital ECGs were not available for this referral center.
All patients received a single dose of aspirin 325 mg, clopidogrel 600 mg and a 5,000 U heparin bolus prior to transfer. Immediate ground transportation was available 24 hours a day/7 days a week and all patients were transferred via ground transportation. On arrival to UVM, all patients were taken directly to the cardiac catheterization laboratory (Figure 1). In 2007, feedback was provided to the referring emergency room director on a monthly basis. Beginning in 2008, same-day feedback on DTB times and outcomes was communicated to both the referring ED physician and nursing staff in order to enhance potential identification of delays.
Time-interval measures. The Transfer STEMI process of care was divided into three time intervals, with a goal of ≤ 30 minutes for each time interval: 1) presentation-to-departure time at the STEMI referring hospital; 2) total transport time; and 3) catheterization laboratory presentation-to-balloon inflation time at UVM (UVM PCI time). Total D2B time was defined as per the CMS guidelines and was measured from registration at the STEMI referring hospital to balloon inflation.17 Time intervals were measured by a dedicated catheterization laboratory quality assurance nurse with correlations with registrations times, catheterization laboratory arrival and balloon inflation times via a computerized chronological log.The accuracy of these times was confirmed by subsequent independent chart review. All time values are reported as median (25th, 75th percentiles).
Clinical outcomes. In-hospital outcomes were confirmed by review of the hospital record, laboratory records and catheterization laboratory database during the entire index hospitalization. Angiographic success and outcomes were determined by review of the index angiogram. Recurrent infarction was defined as new ST elevations or any re-elevation of CK-MB; urgent revascularization was defined as emergent target vessel PCI or CABG; death was defined as mortality due to any cause; major bleeding was defined according to the definition used in the HORIZONS trial:18 any intracranial bleed, retroperitoneal bleed, access-site bleeding requiring intervention, hemoglobin drop > 3g/dl with an overt source and > 4g/dl without an overt source, blood product transfusion, or hematoma > 5 cm.
Statistical analysis. Continuous variables are presented as mean ± standard deviation and compared using the Student’s t-test. Time values are shown as median minutes (25th, 75th percentiles). A p-value of Results
Baseline characteristics. From February 2007 to September 2008, 37 transfer STEMI patients with an age range of 34–92 years were enrolled. More than 70% of patients presented during off hours. The infarct-related artery was the right coronary artery in the majority of the cases and 8% of patients presented in cardiogenic shock (Table 1). Pharmacotherapy was consistent at the transfer institution, with 100% of patients receiving aspirin, clopidogrel and a heparin bolus. At UVM, 51% of patients received heparin plus glycoprotein IIb/IIIa inhibitors (GPI) as PCI pharmacotherapy. Based on results from the HORIZONS trial18, bivalirudin use during PCI increased from 11% to 88% (p Discussion
The ability to transfer patients for primary PCI and achieve the mandated D2B time of ≤ 90 minutes has been an ongoing challenge for patients in the United States. Complicated treatment strategies, difficulties related to transfer of these high-risk patients and the resultant suboptimal D2B times have challenged the feasibility of such an approach.19,20 The UVM Transfer STEMI program was established to streamline STEMI care, provide primary PCI as the revascularization strategy of choice and achieve D2B times of ≤ 90 minutes in > 75% of transfer STEMI patients. We report successful implementation of a streamlined process to achieve D2B times of ≤ 90 minutes in > 70% of STEMI patients transferred from a single referral center for primary PCI.
A meta-analysis of 3,750 STEMI patients showed a 42% relative risk reduction for the cumulative incidence of death, reinfarction or stroke in favor of transfer of patients for primary PCI compared to on-site fibrinolysis.21,22 In the U.S., Henry et al reported data on more than a 1,000 transfer STEMI patients enrolled in the program at the Minneapolis Heart Institute with excellent transfer times and outcomes. Of the 600 patients who presented to referral hospital within 60 miles of the PCI center, the median D2B time was 95 minutes (82, 116), with 40% of patients achieving D2B times of ≤ 90 minutes.10 Our program builds on the Minnesota experience and has transfer D2B times that are almost half the national average, with approximately three-quarters of patients reaching goal D2B times. Our median transfer STEMI D2B time of 82 minutes (77, 91) was also substantially lower than the median D2B times observed in several transfer STEMI clinical trials (DANAMI 2: 112 minutes; PRAGUE: 95 minutes; AIR PAMI: 155 minutes).4,5,22 We recognize that our pilot experience is a single-center referral program and thus is not of the magnitude or complexity of prior reports with respect to patient numbers and inclusion of multiple sites as referral hospitals. We present our pilot data to highlight the feasibility of a streamlined STEMI transfer protocol and the ability to achieve goal D2B times in the majority of patients.
Our program highlights several important aspects of successfully establishing a coordinated regional care network for primary PCI for STEMI. We were able to achieve door-to-departure times of ≤ 30 minutes at the STEMI referring hospital for the majority of the patients. Reports from other STEMI programs have shown that “packaging” of patients at the STEMI referring hospital is frequently the rate-limiting step.12 Data from the Stat Heart program in Illinois and the Air Primary Angioplasty in Myocardial Infarction study demonstrate that the time delay incurred at the referring hospital accounted for 40% and > 50% of the total D2B times, respectively.12,22 Rapid availability of electrocardiograms (ECGs) to the ED physician, a single call activation system for STEMI, simplified pharmacology and availability of immediate emergency medical services ground transportation facilitated timely transfer, resulting in a median door-to-departure time of 26 minutes.
A critical component of the referring door-to-departure time is the upstream pharmacology required for STEMI. Our system used a simple algorithm of aspirin, clopidogrel and bolus unfractionated heparin to facilitate a quick departure from the community hospital ED. The elimination of upstream GPI was based upon the results of the FINESSE trial, suggesting no clear benefit for upstream abciximab.23 When the HORIZONS trial was presented in late 2007 demonstrating a mortality benefit for bivalirudin compared with a routine strategy that uses GPI, we incorporated the use of bivalirudin for STEMI PCI.18 We avoided potential delays associated with upstream initiation of bivalirudin at the STEMI referral center by recommending initial treatment with unfractionated heparin. In the HORIZONS trial, 66% of patients randomized to bivalirudin received an unfractionated heparin bolus prior to the bivalirudin bolus. Thus, we concluded that switching was consistent with clinical trial results and kept the STEMI referral center pharmacology simple (aspirin, clopidogrel and heparin bolus).
Evaluation of times and distances to PCI centers in the U.S. by Nallamothu et al described that the majority of patients could be transferred to a PCI center within 60 minutes,8 suggesting the potential for timely transfer with the implementation of a streamlined, coordinated STEMI protocol. However, out longest delay was encountered during the transfer of patients. Only 17% of our patients were transferred within 30 minutes after leaving the STEMI referring hospital despite a total travel distance of Conclusion
Rapid transfer of STEMI patients using a streamlined process of care can achieve consistent D2B times of ≤ 90 minutes. Successful implementation of a simplified STEMI protocol has the potential to expand the primary PCI for STEMI approach to the majority of U.S hospitals.
_______________________________
From the Department of Cardiology, University of Vermont, Burlington, Vermont.
The authors report no financial relationships or conflicts of interest regarding the content of this manuscript.
Manuscript submitted February 13, 2009, provisional acceptance given April 20, 2009, and final version accepted April 21, 2009.
Address for correspondence: Bina Ahmed, MD, Department of Cardiology, University of Vermont, 111 Colchester Avenue, Burlington, VT 05401. E-mail: bina.ahmed@vtmednet.org
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