Minneapolis STEMI

In rural settings, direct transfer of patients with ST-elevation myocardial infarction (STEMI) for percutaneous coronary intervention (PCI) is often subject to prolonged delays. This prospective study, conducted in Minneapolis, assessed the safety and efficacy of a pharmaco-invasive reperfusion strategy with half-dose fibrinolytic and direct transfer for immediate PCI compared with primary PCI.

 

Between April 2003 and December 2009, 2,634 consecutive STEMI patients were enrolled into the “Level 1 MI” database of the Minneapolis Heart Institute at Abbot-North-western (MHI-ANW) Hospital, in Minneapolis (which uses a standardised protocol to transfer STEMI patients from regional hospitals up to 210 miles from the PCI centre by means of a pharmaco-invasive strategy or for primary PCI). Patients were grouped into those presenting directly to the PCI centre (n=600), a Zone 1 hospital within 60 miles of the PCI centre (n=1,195), or a Zone 2 hospital located more than 60 miles from the PCI centre (n=839). The groups were further subdivided in the Zone 1 and 2 hospitals into those patients receiving a pharmaco-invasive strategy and those transferred directly for primary PCI.

All patients received aspirin, clopidogrel, unfractionated heparin and a beta-blocker on presentation in the emergency room. Patients presenting to Zone 2 hospitals (or Zone 1, if timely transfer for primary PCI was not possible) received half-dose thrombolytic (usually tenecteplase) before being transferred for immediate PCI.

Minneapolis STEMI registry

Minneapolis  STEMI  registry  Flowchart showing components and workflow of Minneapolis STEMI registry

Patients presenting directly to the PCI hospital (Group A) had a median door-to-balloon time of 62 (44, 83) min. Patients transferred from Zone 1 hospitals for PCI had a median door-to-balloon time of 94 (80, 116) min, and those transferred from Zone 2 hospitals for PCI had a medial door-to-balloon time of 122 (100,147) min. The median door-to-needle time for patients receiving pharmaco-invasive treatment was 29 (20, 42) min.

Minneapolis STEMI registry: Time to treatment

Minneapolis  STEMI  registry  Time  to  treatment  Table showing time duration to treatment and the preferred treatment strategy depending on the location of the patient

D2B, door-to-balloon time (first presentation at the hospital to PPCI)

D2N, door-to-needle time (first presentation at the hospital to administration of thrombolytic)

Despite the significantly longer door-to-balloon times for patients from Zone 2, there were no significant differences in 30-day mortality, stroke, recurrent ischaemia/myocardial infarction, or TIMI major bleeding in the comparison between Group A patients who directly underwent PPCI and Group D patients, transferred from hospitals in Zone 2 (60 miles away from the PCI centre), who received a pharmaco-invasive strategy. There was also no significant difference in any of the above factors when the patients treated with PPCI (Groups A and B) were compared with those treated with the pharmaco-invasive strategy (Groups C and D).

Minneapolis STEMI registry: Outcomes

Minneapolis STEMI registry Outcomes  Bar graph comparing incidence of  mortality (30 day), stroke, bleeding and reinfarction or ischaemia in PPCI and Ph-INV treatment groups

Patients in Group E, who were transferred for PPCI had a median door-to-balloon time of 133 min, and a higher in-hospital and 30-day mortality compared to patients in Group D (Zone 2 patients receiving pharmaco-invasive treatment).

A pharmaco-invasive strategy using half-dose thrombolytic may be an effective and safe reperfusion strategy for STEMI patients in rural or isolated settings with delayed transfer times to a PCI centre, when performed within an organised regional network.

References: 

 

  1. Larson DM, et al. Safety and efficacy of a pharmaco-invasive reperfusion strategy in rural ST-elevation myocardial infarction patients with expected delays due to long-distance transfers. Eur Heart J 2012;33:1232-1240.

 

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