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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.

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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: group A (PPCI) vs group D (Ph-INV)

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.

Reference: 

  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.