Use of Helicopters to Reduce Health Care System Delay in Patients With ST-Elevation Myocardial Infarction Admitted to an Invasive Center

Sivagowry Rasalingam Mørk,Morten Thingemann Bøtker,Jakob Hjort,Lisette Okkels Jensen,Frants Pedersen,Gitte Jørgensen,Erika Frischknect Christensen,Marina Krintel Christensen,Jens Aarø,Freddy Lippert,Lars Knudsen,Troels Martin Hansen,Jacob Steinmetz,Christian Juhl Terkelsen

doi:10.1016/j.amjcard.2022.01.042

Abstract

Timely reperfusion in ST-elevation myocardial infarction (STEMI) is essential. This study aimed to evaluate the reduction in system delay (time from emergency medical service [EMS] call to primary percutaneous coronary intervention [PPCI]) in patients with STEMI when using helicopter EMS (HEMS) rather than ground-based EMS (GEMS). This was a retrospective, nationwide cohort study of consecutive patients with STEMI treated with PPCI at 5 PPCI centers in Denmark. Polynomial spline curves were constructed to describe the association between system delay and distance to the PPCI center stratified by transportation mode. A total of 26,433 patients with STEMI were treated with PPCI between January 1, 1999, and December 31, 2016. In 16,436 patients field triaged directly to the PPCI center, the proportion treated within 120 minutes of the EMS call was 75% for those living 0 to 25 km from the PPCI center compared with 65% for all patients transported by GEMS (median transport distance 50 km [interquartile range 23 to 90]) and 64% for all patients transported by HEMS (median transport distance 119 km [interquartile range 99 to 142]). The estimated reduction in system delay owed to using HEMS rather than GEMS was 14, 16, 20, and 29 minutes for patients living 75, 100, 125, and 170 km from a PPCI center. In conclusion, this study confirmed that using HEMS ensures that most patients with STEMI, living up to 170 km from a PPCI center, can be treated within 120 minutes of their EMS call provided they are field triaged directly to the PPCI center.

Highlights

In patients with ST-elevation myocardial infarction (STEMI), primary percutaneous coronary intervention (PPCI) is recommended in preference to fibrinolysis, provided it can be performed within 120 minutes after diagnosis.1 In Denmark, PPCI has been the recommended national reperfusion strategy since 2003.2,3
The present study aimed to evaluate the association between distance to PPCI center and system delay in patients with STEMI transported by helicopter emergency medical service (HEMS) compared with groundbased emergency medical service (GEMS) and to describe the potential reduction in system delay achieved by field triage and direct transport to a PPCI center with HEMS compared with GEMS for patients living in rural areas
When only focusing on field triaged patients, and using second-order polynomial regression analysis, we found an association between transportation distance (x) to the PPCI center and system delay (Y) of: Y = 100.66 + 0.2001x + 0.00071x2 in patients transported by GEMS contemporary and Y = 89.18 + 0.189973x + 0.000398x2 in patients transported by HEMS (Figure 4)

Summary

Introduction

In patients with ST-elevation myocardial infarction (STEMI), primary percutaneous coronary intervention (PPCI) is recommended in preference to fibrinolysis, provided it can be performed within 120 minutes after diagnosis. In Denmark, PPCI has been the recommended national reperfusion strategy since 2003.2,3. In Denmark, PPCI has been the recommended national reperfusion strategy since 2003.2,3. Rather than establishing multiple PPCI centers, a centralized strategy has prevailed with field triage directly to high-volume PPCI centers bypassing local hospitals.. Centralization has increased travel distances and time to specialized treatment for citizens in sparsely populated areas of Denmark.. To counterbalance this, preceded by pilot studies in May 2010, a national helicopter emergency medical service (HEMS) was implemented from October 2014. The present study aimed to evaluate the association between distance to PPCI center and system delay in patients with STEMI transported by HEMS compared with groundbased emergency medical service (GEMS) and to describe the potential reduction in system delay achieved by field triage and direct transport to a PPCI center with HEMS compared with GEMS for patients living in rural areas

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